The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
Artificially produced membranes, such as semipermeable membranes used in artificial kidney dialysis (RENAL DIALYSIS), monomolecular and bimolecular membranes used as models to simulate biological CELL MEMBRANES. These membranes are also used in the process of GUIDED TISSUE REGENERATION.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
A darkly stained mat-like EXTRACELLULAR MATRIX (ECM) that separates cell layers, such as EPITHELIUM from ENDOTHELIUM or a layer of CONNECTIVE TISSUE. The ECM layer that supports an overlying EPITHELIUM or ENDOTHELIUM is called basal lamina. Basement membrane (BM) can be formed by the fusion of either two adjacent basal laminae or a basal lamina with an adjacent reticular lamina of connective tissue. BM, composed mainly of TYPE IV COLLAGEN; glycoprotein LAMININ; and PROTEOGLYCAN, provides barriers as well as channels between interacting cell layers.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Glycoproteins found on the membrane or surface of cells.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Established cell cultures that have the potential to propagate indefinitely.
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
The two lipoprotein layers in the MITOCHONDRION. The outer membrane encloses the entire mitochondrion and contains channels with TRANSPORT PROTEINS to move molecules and ions in and out of the organelle. The inner membrane folds into cristae and contains many ENZYMES important to cell METABOLISM and energy production (MITOCHONDRIAL ATP SYNTHASE).
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
Transport proteins that carry specific substances in the blood or across cell membranes.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a choline moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and choline and 2 moles of fatty acids.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Proteins found in any species of bacterium.
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
The sum of the weight of all the atoms in a molecule.
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
Elements of limited time intervals, contributing to particular results or situations.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The rate dynamics in chemical or physical systems.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The thin layers of tissue that surround the developing embryo. There are four extra-embryonic membranes commonly found in VERTEBRATES, such as REPTILES; BIRDS; and MAMMALS. They are the YOLK SAC, the ALLANTOIS, the AMNION, and the CHORION. These membranes provide protection and means to transport nutrients and wastes.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially FACILITATED DIFFUSION, is a major mechanism of BIOLOGICAL TRANSPORT.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.
Minute projections of cell membranes which greatly increase the surface area of the cell.
The ability of a substrate to allow the passage of ELECTRONS.
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
Proteins prepared by recombinant DNA technology.
Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to a serine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and serine and 2 moles of fatty acids.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to an ethanolamine moiety. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid and ethanolamine and 2 moles of fatty acids.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
The voltage difference, normally maintained at approximately -180mV, across the INNER MITOCHONDRIAL MEMBRANE, by a net movement of positive charge across the membrane. It is a major component of the PROTON MOTIVE FORCE in MITOCHONDRIA used to drive the synthesis of ATP.
A major integral transmembrane protein of the ERYTHROCYTE MEMBRANE. It is the anion exchanger responsible for electroneutral transporting in CHLORIDE IONS in exchange of BICARBONATE IONS allowing CO2 uptake and transport from tissues to lungs by the red blood cells. Genetic mutations that result in a loss of the protein function have been associated with type 4 HEREDITARY SPHEROCYTOSIS.
A high molecular weight (220-250 kDa) water-soluble protein which can be extracted from erythrocyte ghosts in low ionic strength buffers. The protein contains no lipids or carbohydrates, is the predominant species of peripheral erythrocyte membrane proteins, and exists as a fibrous coating on the inner, cytoplasmic surface of the membrane.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
Functionally and structurally differentiated, purple-pigmented regions of the cytoplasmic membrane of some strains of Halobacterium halobium. The membrane develops under anaerobic conditions and is made almost entirely of the purple pigment BACTERIORHODOPSINS. (From Singleton & Sainsbury Dictionary of Microbiology and Molecular Biology, 2d ed)
Single membrane vesicles, generally made of PHOSPHOLIPIDS.
Measurement of the intensity and quality of fluorescence.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
A replica technique in which cells are frozen to a very low temperature and cracked with a knife blade to expose the interior surfaces of the cells or cell membranes. The cracked cell surfaces are then freeze-dried to expose their constituents. The surfaces are now ready for shadowing to be viewed using an electron microscope. This method differs from freeze-fracturing in that no cryoprotectant is used and, thus, allows for the sublimation of water during the freeze-drying process to etch the surfaces.
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
Proteins obtained from ESCHERICHIA COLI.
Cyclic GLUCANS consisting of seven (7) glucopyranose units linked by 1,4-glycosidic bonds.
Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.
A fold of the mucous membrane of the CONJUNCTIVA in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the CORNEA.
The inner layer of CHOROID, also called the lamina basalis choroideae, located adjacent to the RETINAL PIGMENT EPITHELIUM; (RPE) of the EYE. It is a membrane composed of the basement membranes of the choriocapillaris ENDOTHELIUM and that of the RPE. The membrane stops at the OPTIC NERVE, as does the RPE.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
An enzyme that catalyzes the active transport system of sodium and potassium ions across the cell wall. Sodium and potassium ions are closely coupled with membrane ATPase which undergoes phosphorylation and dephosphorylation, thereby providing energy for transport of these ions against concentration gradients.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The relationship between the dose of an administered drug and the response of the organism to the drug.
Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Antibodies produced by a single clone of cells.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
A class of sphingolipids found largely in the brain and other nervous tissue. They contain phosphocholine or phosphoethanolamine as their polar head group so therefore are the only sphingolipids classified as PHOSPHOLIPIDS.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
A product of COMPLEMENT ACTIVATION cascade, regardless of the pathways, that forms transmembrane channels causing disruption of the target CELL MEMBRANE and cell lysis. It is formed by the sequential assembly of terminal complement components (COMPLEMENT C5B; COMPLEMENT C6; COMPLEMENT C7; COMPLEMENT C8; and COMPLEMENT C9) into the target membrane. The resultant C5b-8-poly-C9 is the "membrane attack complex" or MAC.
The thermodynamic interaction between a substance and WATER.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Orientation of intracellular structures especially with respect to the apical and basolateral domains of the plasma membrane. Polarized cells must direct proteins from the Golgi apparatus to the appropriate domain since tight junctions prevent proteins from diffusing between the two domains.
RED BLOOD CELL sensitivity to change in OSMOTIC PRESSURE. When exposed to a hypotonic concentration of sodium in a solution, red cells take in more water, swell until the capacity of the cell membrane is exceeded, and burst.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Porins are protein molecules that were originally found in the outer membrane of GRAM-NEGATIVE BACTERIA and that form multi-meric channels for the passive DIFFUSION of WATER; IONS; or other small molecules. Porins are present in bacterial CELL WALLS, as well as in plant, fungal, mammalian and other vertebrate CELL MEMBRANES and MITOCHONDRIAL MEMBRANES.
Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
A nitrogen-free class of lipids present in animal and particularly plant tissues and composed of one mole of glycerol and 1 or 2 moles of phosphatidic acid. Members of this group differ from one another in the nature of the fatty acids released on hydrolysis.
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.
The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.
Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.
Adherence of cells to surfaces or to other cells.
Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.
Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.
Derivatives of phosphatidic acids in which the phosphoric acid is bound in ester linkage to the hexahydroxy alcohol, myo-inositol. Complete hydrolysis yields 1 mole of glycerol, phosphoric acid, myo-inositol, and 2 moles of fatty acids.
Proteins which are involved in the phenomenon of light emission in living systems. Included are the "enzymatic" and "non-enzymatic" types of system with or without the presence of oxygen or co-factors.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Condensed areas of cellular material that may be bounded by a membrane.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
The characteristic three-dimensional shape of a molecule.
Characteristics or attributes of the outer boundaries of objects, including molecules.
Measurement of the polarization of fluorescent light from solutions or microscopic specimens. It is used to provide information concerning molecular size, shape, and conformation, molecular anisotropy, electronic energy transfer, molecular interaction, including dye and coenzyme binding, and the antigen-antibody reaction.
Major constituent of the cytoskeleton found in the cytoplasm of eukaryotic cells. They form a flexible framework for the cell, provide attachment points for organelles and formed bodies, and make communication between parts of the cell possible.
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
Spontaneous tearing of the membranes surrounding the FETUS any time before the onset of OBSTETRIC LABOR. Preterm PROM is membrane rupture before 37 weeks of GESTATION.
A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.
An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.
A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC
A cell line derived from cultured tumor cells.
A layer of the cornea. It is the basal lamina of the CORNEAL ENDOTHELIUM (from which it is secreted) separating it from the CORNEAL STROMA. It is a homogeneous structure composed of fine collagenous filaments, and slowly increases in thickness with age.
Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
A tyrosine phosphoprotein that plays an essential role in CAVEOLAE formation. It binds CHOLESTEROL and is involved in LIPIDS transport, membrane traffic, and SIGNAL TRANSDUCTION.
Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.
Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.
Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)
Application of a life support system that circulates the blood through an oxygenating system, which may consist of a pump, a membrane oxygenator, and a heat exchanger. Examples of its use are to assist victims of smoke inhalation injury, respiratory failure, and cardiac failure.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.
A complex of polyene antibiotics obtained from Streptomyces filipinensis. Filipin III alters membrane function by interfering with membrane sterols, inhibits mitochondrial respiration, and is proposed as an antifungal agent. Filipins I, II, and IV are less important.
Direct contact of a cell with a neighboring cell. Most such junctions are too small to be resolved by light microscopy, but they can be visualized by conventional or freeze-fracture electron microscopy, both of which show that the interacting CELL MEMBRANE and often the underlying CYTOPLASM and the intervening EXTRACELLULAR SPACE are highly specialized in these regions. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p792)
Particles consisting of aggregates of molecules held loosely together by secondary bonds. The surface of micelles are usually comprised of amphiphatic compounds that are oriented in a way that minimizes the energy of interaction between the micelle and its environment. Liquids that contain large numbers of suspended micelles are referred to as EMULSIONS.
A fluorescent compound that emits light only in specific configurations in certain lipid media. It is used as a tool in the study of membrane lipids.
A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.
The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability.
The membrane system of the CELL NUCLEUS that surrounds the nucleoplasm. It consists of two concentric membranes separated by the perinuclear space. The structures of the envelope where it opens to the cytoplasm are called the nuclear pores (NUCLEAR PORE).

The structlre of pili (fimbriae) of Moraxella bovis. (1/52017)

Cells from rough and smooth colonies of Moraxella bovis were examined by electron microscopy utilizing both shadowing and thin sectioning techniques. Pili were found on the surfaces of cells from rough but not smooth colonies. Pili had a peritrichoud distribution and appeared as delicate (6.5-8.5 nm in diameter), elongated unbranched filaments. When bacteria were sectioned pili did not contain central pores and appeared to originate from opacities on the surface of the cell wall.  (+info)

Glycopeptides from the surgace of human neuroblastoma cells. (2/52017)

Glycopeptides suggesting a complex oligosaccharide composition are present on the surface of cells from human neuroblastoma tumors and several cell lines derived from the tumors. The glycopeptides, labeled with radioactive L-fucose, were removed from the cell surface with trypsin, digested with Pronase, and examined by chromatography on Sephadex G-50. Human skin fibroblasts, brain cells, and a fibroblast line derived from neuroblastoma tumor tissue show less complex glycopeptides. Although some differences exist between the cell lines and the primary tumor cells, the similarities between these human tumors and animal tumors examined previously are striking.  (+info)

The effects of digestive enzymes on characteristics of placental insulin receptor. Comparison of particulate and soluble receptor preparations. (3/52017)

The role of the surrounding membrane structure on the binding characteristics of the insulin receptor was studied by using several digestive enzymes. The effects observed with particulate membrane preparations are compared with those from soluble receptor preparations. beta-Galactosidase and neuraminidase had no effect on insulin binding to either particulate or soluble receptors from human placentae. Exposure to 2 units of phospholipase C/ml increased insulin binding to particulate membranes, but was without effect on the soluble receptor preparation. The increase in binding to particulate membranes was shown to be due to an increase in apparent receptor number. After 5 min exposure to 500 microgram of trypsin/ml there was an increase in insulin binding to the particulate membrane fraction, owing to an increase in receptor affinity. After 15 min exposure to this amount of trypsin, binding decreased, owing to a progressive decrease in receptor availability. In contrast, this concentration of trypsin had no effect on the solubilized receptor preparation. Because of the differential effects of phospholipase C and trypsin on the particulate compared with the solubilized receptor preparations, it is concluded that the effects of these enzymes were due to an effect on the surrounding membrane structure. Changes in receptor configuration due to alterations within the adjoining membrane provide a potential mechanism for mediating short-term alterations in receptor function.  (+info)

Structural and functional changes in acute liver injury. (4/52017)

Carbon tetrachloride produces liver cell injury in a variety of animal species. The first structurally recognizable changes occur in the endoplasmic reticulum, with alteration in ribosome-membrane interactions. Later there is an increase in intracellular fat, and the formation of tangled nets of the ergastoplasm. At no time are there changes in mitochondria or single membrane limited bodies in cells with intact plasmalemma, although a relative increase in cell sap may appear. In dead cells (those with plasmalemma discontinuties) crystalline deposits of calcium phosphatase may be noted. Functional changes are related to the endoplasmic reticulum and the plasma membrane. An early decrease in protein synthesis takes place; an accumulation of neutral lipid is related to this change. Later alterations in the ergastoplasmic functions (e.g., mixed function oxidation) occurs. Carbon tetrachloride is not the active agent; rather, a product of its metabolism, probably the CC1, free radical, is. The mechanisms of injury include macromolecular adduction and peroxide propagation. A third possibility includes a cascade effect with the production of secondary and tertiary products, also toxic in nature, with the ability to produce more widespread damage to intracellular structures.  (+info)

Dopamine stimulates salivary duct cells in the cockroach Periplaneta americana. (5/52017)

This study examines whether the salivary duct cells of the cockroach Periplaneta americana can be stimulated by the neurotransmitters dopamine and serotonin. We have carried out digital Ca2+-imaging experiments using the Ca2+-sensitive dye fura-2 and conventional intracellular recordings from isolated salivary glands. Dopamine evokes a slow, almost tonic, and reversible dose-dependent elevation in [Ca2+]i in the duct cells. Upon stimulation with 10(-)6 mol l-1 dopamine, [Ca2+]i rises from 48+/-4 nmol l-1 to 311+/-43 nmol l-1 (mean +/- s.e.m., N=18) within 200-300 s. The dopamine-induced elevation in [Ca2+]i is absent in Ca2+-free saline and is blocked by 10(-)4 mol l-1 La3+, indicating that dopamine induces an influx of Ca2+ across the basolateral membrane of the duct cells. Stimulation with 10(-)6 mol l-1 dopamine causes the basolateral membrane to depolarize from -67+/-1 to -41+/-2 mV (N=10). This depolarization is also blocked by La3+ and is abolished when Na+ in the bath solution is reduced to 10 mmol l-1. Serotonin affects neither [Ca2+]i nor the basolateral membrane potential of the duct cells. These data indicate that the neurotransmitter dopamine, which has previously been shown to stimulate fluid secretion from the glands, also stimulates the salivary duct cells, suggesting that dopamine controls their most probable function, the modification of primary saliva.  (+info)

Plasma membrane recruitment of RalGDS is critical for Ras-dependent Ral activation. (6/52017)

In COS cells, Ral GDP dissociation stimulator (RalGDS)-induced Ral activation was stimulated by RasG12V or a Rap1/Ras chimera in which the N-terminal region of Rap1 was ligated to the C-terminal region of Ras but not by Rap1G12V or a Ras/Rap1 chimera in which the N-terminal region of Ras was ligated to the C-terminal region of Rap1, although RalGDS interacted with these small GTP-binding proteins. When RasG12V, Ral and the Rap1/Ras chimera were individually expressed in NIH3T3 cells, they localized to the plasma membrane. Rap1Q63E and the Ras/Rap1 chimera were detected in the perinuclear region. When RalGDS was expressed alone, it was abundant in the cytoplasm. When coexpressed with RasG12V or the Rap1/Ras chimera, RalGDS was detected at the plasma membrane, whereas when coexpressed with Rap1Q63E or the Ras/Rap1 chimera, RalGDS was observed in the perinuclear region. RalGDS which was targeted to the plasma membrane by the addition of Ras farnesylation site (RalGDS-CAAX) activated Ral in the absence of RasG12V. Although RalGDS did not stimulate the dissociation of GDP from Ral in the absence of the GTP-bound form of Ras in a reconstitution assay using the liposomes, RalGDS-CAAX could stimulate it without Ras. RasG12V activated Raf-1 when they were coexpressed in Sf9 cells, whereas RasG12V did not affect the RalGDS activity. These results indicate that Ras recruits RalGDS to the plasma membrane and that the translocated RalGDS induces the activation of Ral, but that Rap1 does not activate Ral due to distinct subcellular localization.  (+info)

Membrane deinsertion of SecA underlying proton motive force-dependent stimulation of protein translocation. (7/52017)

The proton motive force (PMF) renders protein translocation across the Escherichia coli membrane highly efficient, although the underlying mechanism has not been clarified. The membrane insertion and deinsertion of SecA coupled to ATP binding and hydrolysis, respectively, are thought to drive the translocation. We report here that PMF significantly decreases the level of membrane-inserted SecA. The prlA4 mutation of SecY, which causes efficient protein translocation in the absence of PMF, was found to reduce the membrane-inserted SecA irrespective of the presence or absence of PMF. The PMF-dependent decrease in the membrane-inserted SecA caused an increase in the amount of SecA released into the extra-membrane milieu, indicating that PMF deinserts SecA from the membrane. The PMF-dependent deinsertion reduced the amount of SecA required for maximal translocation activity. Neither ATP hydrolysis nor exchange with external SecA was required for the PMF-dependent deinsertion of SecA. These results indicate that the SecA deinsertion is a limiting step of protein translocation and is accelerated by PMF, efficient protein translocation thereby being caused in the presence of PMF.  (+info)

The exocyst is an effector for Sec4p, targeting secretory vesicles to sites of exocytosis. (8/52017)

Polarized secretion requires proper targeting of secretory vesicles to specific sites on the plasma membrane. Here we report that the exocyst complex plays a key role in vesicle targeting. Sec15p, an exocyst component, can associate with secretory vesicles and interact specifically with the rab GTPase, Sec4p, in its GTP-bound form. A chain of protein-protein interactions leads from Sec4p and Sec15p on the vesicle, through various subunits of the exocyst, to Sec3p, which marks the sites of exocytosis on the plasma membrane. Sec4p may control the assembly of the exocyst. The exocyst may therefore function as a rab effector system for targeted secretion.  (+info)

TY - JOUR. T1 - Characterization of apical and basolateral plasma membrane domains derived from cultured rat cholangiocytes. AU - Tietz, Pamela. AU - Levine, Susan. AU - Holman, Ralph. AU - Fretham, Chris. AU - La Russo, Nicholas F. PY - 1997/12/15. Y1 - 1997/12/15. N2 - Cholangiocytes, the epithelial cells that line intrahepatic bile ducts, are composed of plasma membranes with discrete apical (lumenal) and basolateral domains that contain different channels, transporters, and receptors. In recent work, we developed a long-term, primary culture system of normal rat cholangiocytes (NRC). Our aims here were to prepare and characterize apical and basolateral plasma membrane vesicles from NRC. Using serial isopycnic centrifugation on sucrose gradients, we generated separate apical and basolateral plasma membrane vesicles. We characterized these vesicles by transmission electron microscopy, specific marker enzyme assays, and immunoblotting; we also determined the percentage of sealed vesicles and ...
Al, hamdani M.; Atkinson, M E.; and Mayhew, T M., Changes in the plasma membrane surface of lymphocytes stimulated in vivo with dncb. (1979). Subject Strain Bibliography 1979. 2522 ...
TY - JOUR. T1 - Loss of cytoskeletal support is not sufficient for anoxic plasma membrane disruption in renal cells. AU - Chen, Jing. AU - Dai, Jianwu. AU - Grant, Roberta L.. AU - Doctor, R. Brian. AU - Sheetz, Michael. AU - Mandel, Lazaro J.. PY - 1997/5/21. Y1 - 1997/5/21. N2 - The goal of this study was to determine whether anoxic membrane disruption is initiated by loss of cytoskeletal support in rabbit renal proximal tubules (PT). We specifically tested 1) whether cytoskeletal perturbation affects membrane integrity under normoxia, 2) whether cytoskeletal perturbation potentiates anoxic membrane damage, and 3) whether the membrane protection by glycine depends on cytoskeletal integrity. Cytoskeletal perturbation was achieved with 10 μM cytochalasin D (CD) because it selectively disturbs F-actin organization and has similar effects as anoxia on the cytoskeleton of PT. During normoxia, CD caused decreased basal F-actin content, microvillar breakdown, and membrane-cytoskeleton dissociation, ...
BackgroundIngestion of the lectins present in certain improperly cooked vegetables can result in acute GI tract distress, but the mechanism of toxicity is unknown. In vivo, gut epithelial cells are constantly exposed to mechanical and other stresses and consequently individual cells frequently experience plasma membrane disruptions. Repair of these cell surface disruptions allows the wounded cell to survive: failure results in necrotic cell death. Plasma membrane repair is mediated, in part, by an exocytotic event that adds a patch of internal membrane to the defect site. Lectins are known to inhibit exocytosis. We therefore tested the novel hypothesis that lectin toxicity is due to an inhibitory effect on plasma membrane repair.Methods and FindingsRepair of plasma membrane disruptions and exocytosis of mucus was assessed after treatment of cultured cell models and excised segments of the GI tract with lectins. Plasma membrane disruptions were produced by focal irradiation of individual cells, using a
1. A liver canalicular plasma-membrane fraction enriched 115-155-fold in five marker enzymes relative to the tissue homogenate was obtained by sonication of liver plasma membranes followed by fractionation in iso-osmotic Nycodenz gradients. 2. Two lateral-plasma membrane fractions were also collected by this procedure; the lighter-density fraction was still associated with canalicular membranes, as assessed by enzymic and polypeptide analysis. 3. The polypeptide composition of the domain-defined plasma-membrane fractions was evaluated. It was demonstrated by immunoblotting that the 41 kDa alpha-subunit of the inhibitory G-protein, associated in high relative amounts with canalicular plasma-membrane fractions, was partially lost in the last stage of purification; however, this subunit was retained by lateral plasma membranes. 4. Antibodies to the proteins of bile-canalicular vesicles were shown to localize to the hepatocyte surface in thin liver sections examined by immunofluorescent and ...
Cell-free studies have demonstrated how collective action of actin-associated proteins can organize actin filaments into dynamic patterns, such as vortices, asters and stars. Using complementary microscopic techniques, we here show evidence of such self-organization of the actin cortex in living HeLa cells. During cell adhesion, an active multistage process naturally leads to pattern transitions from actin vortices over stars into asters. This process is primarily driven by Arp2/3 complex nucleation, but not by myosin motors, which is in contrast to what has been theoretically predicted and observed in vitro. Concomitant measurements of mechanics and plasma membrane fluidity demonstrate that changes in actin patterning alter membrane architecture but occur functionally independent of macroscopic cortex elasticity. Consequently, tuning the activity of the Arp2/3 complex to alter filament assembly may thus be a mechanism allowing cells to adjust their membrane architecture without affecting their
Plasma membrane-derived vesicles (PMVs) are released into circulation in response to normal and stress/pathogenic conditions. They are of tremendous significance for the prediction, diagnosis, and observation of the therapeutic success of many diseases. Knowledge of their molecular characteristics and therefore functional properties would contribute to a better understanding of the pathological mechanisms leading to various diseases in which their levels are raised. The review aims at outlining and discussing the molecular characteristics of PMVs in order to bring to the fore some aspects/characteristics of PMVs that will assist the scientific community to properly understand the role of PMVs in various physiological and pathological processes. The review covers PMVs characterisation and discusses how distinct they are from exosomes and endosomes. Also, methods of PMVs analysis, importance of proper PMV level estimation/characterisation, PMVs and their constituents as well as their therapeutic
Considerable controversy arose over the concept that cholesterol/sphingolipid-rich rafts in the T cell plasma membrane serve as a platform for TCR signalling reactions. This controversy was founded on the initial definition of rafts as detergent resistant membranes which later turned out to misrepresent many features of cell membrane organisation under physiological conditions. Raft-organisation was subsequently studied using a number of detergent-free experimental approaches. The results led to a refined perception of membrane rafts which resolves the controversies. Here we review new biophysical and biochemical data which provide an updated picture of the highly dynamic nanometer-sized cholesterol/sphingolipid-rich raft domains stabilised by protein-networks to form TCR signalling platforms in the T cell plasma membrane.
Plasma membrane-derived vesicles (PMVs) are released into circulation in response to normal and stress/pathogenic conditions. They are of tremendous significance for the prediction, diagnosis, and observation of the therapeutic success of many diseases. Knowledge of their molecular characteristics and therefore
Cell membranes are structured so that molecules can pass in and out of the cell across them. While both plant and animal cells have membranes, plant...
Cell membranes are structures of contradictions. These oily films are hundreds of times thinner than a strand of spider silk, yet strong enough to protect the delicate contents of life: the cells watery cytoplasm, genetic material, organelles, and all the molecules it needs to survive. How does the membrane work, and where does that strength come from? Nazzy Pakpour investigates ...
The distribution of [3H]leukotriene D4 [( 3H]LTD4) receptors in subcellular membrane fractions obtained from sheep tracheal smooth muscle was studied. Using differential centrifugation and discontinuous sucrose density gradient centrifugation, the subcellular membranes were separated into six fractions. The [3H]LTD4 receptor distribution profile in these fractions correlated with markers for the plasma membrane (5-nucleotidase and alkaline phosphodiesterase) and did not correlate with markers for the mitochondria (cytochrome c oxidase and succinate-dependent cytochrome c reductase). The dissociation constant (Kd) and maximum number of binding sites (Bmax) for [3H]LTD4 binding to the receptors in the crude mixture of membranes (PII) were 0.38 +/- 0.2 nM and 77 +/- 14 fmol/mg of protein, respectively. The Kd and Bmax of [3H]LTD4 binding to the receptors in the plasma membrane-enriched fraction (FII) were 0.40 +/- 0.2 nM and 268 +/- 46 fmol/mg of protein, respectively. The specificity profile of ...
Plasma membrane-enriched fractions were isolated from human gliomas and brain white matter. These membrane fractions were characterized by electron microscopy and by the distribution of the membrane...
Norma Andrews (UMCP) 1: Mechanisms of Plasma Membrane Repair Dr. Norma Andrews overviews the mechanisms of cellular plasma membrane repair. Part 1: Mechanisms of Plasma Membrane Repair: Norma Andrews overviews the
Antibodies for proteins involved in cytoskeletal anchoring at plasma membrane pathways, according to their Panther/Gene Ontology Classification
DC-Research Knowledge Portal: Transcriptional analysis of the integral plasma membrane proteome of D1 cells stimulated with LPS harvested at different time-points
In this study, we identified a novel domain, the EFC domain, which is related to the BAR domain. Half of the EFC domain was previously characterized as an FCH domain, but an additional sequence is required for interaction with the membrane. Our results provide the first evidence that the EFC domain of FBP17 directly binds to the membrane and deforms protein-free liposomes into tubules. Moreover, the EFC domains of other PCH family proteins, such as CIP4, FER, PSTPIP1, and PSTPIP2, also strongly bind to and tubulate liposomes (Figs. 3 and 4). Conservation of both amino acid sequence and function indicate that the EFC domain is a membrane tubulation module that is dependent on lipid binding.. The SH3 domain of FBP17 and that of other EFC domain-containing proteins bind to dynamin-2 and N-WASP. Dimerized FBP17 recruited N-WASP and dynamin-2 simultaneously (Figs. 7 and 8). N-WASP and dynamin preferentially bind to PI(4,5)P2 (Ho et al., 2004; Praefcke and McMahon, 2004). The EFC domain of FBP17 binds ...
The signals that direct membrane proteins to the apical or basolateral plasma membrane domains of polarized epithelial cells are not known. Several of the class of proteins anchored in the membrane by glycosyl-phosphatidylinositol (GPI) are expressed on the apical surface of such cells. However, it is not known whether the mechanism of membrane anchorage or the polypeptide sequence provides the sorting information. The conversion of the normally basolateral vesicular stomatitis virus glycoprotein (VSV G) to a GPI-anchored protein led to its apical expression. Conversely, replacement of the GPI anchor of placental alkaline phosphatase with the transmembrane and cytoplasmic domains of VSV G shifted its expression from the apical to the basolateral surface. Thus, the mechanism of membrane anchorage can determine the sorting of proteins to the apical or basolateral surface, and the GPI anchor itself may provide an apical transport signal. ...
Voltage-gated K+ (Kv) channels play a key role in establishing the resting membrane potential, shaping action potential repolarization and regulating spike frequency in many cell types. These channels often target specific plasma membrane regions where they probably assemble into signaling complexes. However, in most cases little is known about the mechanisms responsible for this localization, even though the modulation of voltage-gated ion channel surface expression and localization probably represents a central mechanism in the regulation of cellular excitability. Given the central role that the Kv2.1 delayed rectifier plays in neurons (Du et al., 2000; Misonou et al., 2005b), the heart (Nerbonne, 2000), pancreatic β cells (Tamarina et al., 2005) and vascular smooth muscle (Coppock et al., 2001), a greater understanding of the mechanisms regulating its surface localization is essential.. As originally noted by Trimmer and colleagues (Scannevin et al., 1996), Kv2.1 is expressed primarily in ...
The production of external membrane vesicles by Gram-negative bacteria has been well documented; however, the mechanism behind the biogenesis of these vesicles remains unclear. have led to several different models describing how Gram-negative bacteria produce OMVs. Data showing that OMV lipids differ from the lipids of the OM, such as the aforementioned statement on OMVs, have led to a model in which membrane curvature is definitely induced from the build up of LPS molecules with atypical constructions or costs. LPS is the major constituent of the outer leaflet of the OM of most Gram-negative bacteria. The LPS molecules themselves are not homogeneous; the space and content material of the polysaccharide chain varies among the different molecules. It is proposed that subsets of these molecules may gather in patches along the OM, inducing higher BIIB021 examples of membrane curvature at particular locations, either due to charge repulsion [22] or their molecular shape [23]. A second, but not ...
The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can
The function of any given biological membrane is determined largely by the specific set of integral membrane proteins embedded in it, and the peripheral membrane proteins attached to the membrane surface. The activity of these proteins, in turn, can be modulated by the phospholipid composition of the membrane. The reconstitution of membrane proteins into a model membrane allows investigation of individual features and activities of a given cell membrane component. However, the activity of membrane proteins is often difficult to sustain following reconstitution, since the composition of the model phospholipid bilayer differs from that of the native cell membrane. This review will discuss the reconstitution of membrane protein activities in four different types of model membrane - monolayers, supported lipid bilayers, liposomes and nanodiscs, comparing their advantages in membrane protein reconstitution. Variation in the surrounding model environments for these four different types of membrane layer can
The pathological importance of tumor necrosis factor (TNF)-alpha in rheumatoid arthritis (RA) is now widely accepted. Ex vivo data from synovial cell cultures suggest that direct cell contact between activated T-cells and macrophages may be an important driver of macrophage TNF-alpha production in the RA joint. However, the ligand/receptor pairs driving this cell contact signal remain obscure. One reason for this is that plasma membrane (PM) proteins are resistant to systematic analysis using traditional proteomic approaches. In this chapter we present a method for the enrichment and resolution of PM proteins from murine T-cell hybridomas as a prelude to identification by tandem mass spectrometry. We used cell surface biotinylation, differential centrifugation and subsequent streptavidin affinity capture, followed by solution phase iso-electric focussing and tandem mass spectrometry to identify 75 PM proteins and make semiquantitative comparisons of resting and activated cells. The method is applicable
The connection between T cell activation, plasma membrane order and actin filament dynamics was the main focus of this study. Laurdan and di-4-ANEPPDHQ, membrane order sensing probes, were shown to report only on lipid packing rather than being influenced by the presence of membrane-inserted peptides justifying their use in membrane order studies. These dyes were used to follow plasma membrane order in live cells at 37°C. Disrupting actin filaments had a disordering effect while stabilizing actin filaments had an ordering effect on the plasma membrane, indicating there is a basal level of ordered domains in resting cells. Lowering PI(4,5)P2 levels decreased the proportion of ordered domains strongly suggesting that the connection of actin filaments to the plasma membrane is responsible for the maintaining the level of ordered membrane domains. Membrane blebs, which are detached from the underlying actin filaments, contained a low fraction of ordered domains. Aggregation of membrane components ...
enerated within this study cGKI-deficient mice. None of our antisera detected certain phospho-cGKI signals in the freshly isolated tissues (information not
TY - JOUR. T1 - Direct effect of insulin on the synthesis of specific plasma proteins. T2 - Biphasic response of hepatocytes cultured in serum- and hormone-free medium. AU - Liang, T. J.. AU - Grieninger, G.. PY - 1981. Y1 - 1981. N2 - Monolayers of chicken embryo hepatocytes, cultured in chemically defined medium, retain the ability to synthesize a wide spectrum of plasma proteins for several days in the absence of added hormones. Addition of insulin to the medium elicited a biphasic stimulation of plasma protein synthesis: a rapid response of the synthesis of a limited number of plasma proteins (e.g., albumin and α1-globulin M), then, after prolonged exposure to the hormone, the involvement of additional plasma proteins (e.g., fibrinogen and lipoproteins). Synthesis of transferrin and a few other plasma proteins was not affected by the presence of insulin. The degree of stimulation for the most responsive plasma proteins ranged between 2- to 4-fold during the early phase and 10- and even ...
The exocyst is a protein complex that has been found to be essential for exocytosis underlying neurite outgrowth (Hsu et al., 2004). Several models have been proposed to explain how the exocyst complex promotes exocytosis, including modulating cytoskeletal activity and tethering vesicles to the plasma membrane. Targeting of the exocyst complex to spatially defined domains, such as growth cones, is expected to be essential for a focused function of the exocyst complex. In this regard, exocyst subunits have been found to associate with various scaffold proteins such as PSD95 and SAP102 that target plasma membrane proteins to specific plasma membrane subdomains (Riefler et al., 2003; Sans et al., 2003) or with plasma membrane receptors, such as the glycine receptor GLYT1 (Cubelos et al., 2005).. In this manuscript, we identify NCAM as a novel binding partner of the exocyst complex. Several studies have shown that NCAM plays an important role in neural development by regulating neurite outgrowth. In ...
One mode of regulation occurs directly at the level of Rho, where activation of Rho causes PM blebbing. This can be mediated by extracellular signals (see the next section) or by intracellular signaling cascades, such as the up-regulation of RhoA in the absence of the tumor suppressor p53 (Gadea et al., 2007). PM blebbing as a result of Rho activation can also occur indirectly via the Rac GTPase, whose activity is tightly balanced with that of Rho (Sander et al., 1999). In one such example, expression of FilGAP suppresses the activity of Rac, leading to cross talk regulation of RhoA and subsequent membrane blebbing (Ohta et al., 2006). Similar events likely explain extensive PM blebbing after overexpression of an effector loop mutant of active Rac1 (Schwartz et al., 1998) or Dictyostelium discoideum RacB (Lee et al., 2003) as well as the complete lack of Rac1 expression (Vidali et al., 2006). As indicated by the potent suppression of PM blebbing by specific inhibitors of ROCK (Table I), ...
At one time cell membranes were believed to just be envelopes surrounding cells. However, it has been nearly forty years since the structure of the cell membrane was deciphered leading to the development of the Lipid Bi-Layer Fluid Mosaic Model. In this model cell membranes are no longer seen as merely envelopes, they become dynamic structures that play critical roles in the health and detoxification of cells, and the cells unique ability to work in concert - thus keeping us in good health.. Lipids - or fats - are the main component of cell membranes. Lipids in cell membranes are actually phospholipids - or a combination of fats and phosphorus - and not just fats. They dont just sit idly by doing nothing; they contribute to every aspect of cellular energy, detoxification, and optimal function.. Healthy cell-membranes lead to healthy cells, a healthy body, plenty of energy, healthy aging, and so forth. Among other things, cell membranes incorporate hormone receptors that, if sound, will promote ...
In the present study, we identified a critical trafficking determinant in the KCNQ1 channel. Significantly, the structure is the target of several LQT1 associated mutations. The N-terminal location of the trafficking domain was unexpected because previous studies highlighted the C-terminal domain as the key determinant of subunits assembly and processing in the secretory pathway.7,8,25 Indeed, we showed that the deletion of the initial 114 residues, but not the 106 initial residues, abolished plasma membrane expression of the channel. This suggested that residues 106 to 114 may constitute an ER export signal or that the amino acid sequence beyond L114 encodes a retention motif. Studies designed to test these ideas (Figure 7) revealed that these discrete structures do not function as independent, autologous trafficking signals. Indeed, they suggest that the structural integrity of the entire region preceding the first transmembrane domain is essential for proper trafficking of the ...
Membrane reservoirs serve as membrane buffers that help redistribute membrane area when cells need to stretch or change shape and size. They are found at the cell surface as membrane superstructures varying in size from large membrane folds, to tiny membrane invaginations and caveolae (reviewed in [1]).. Cells are often subject to frequent morphological changes throughout life. For example, cellular processes like phagocytosis and migration require protrusion-driven movement and cell shape changes. At the tissue and organ level, critical biological processes such as respiration and the cardiac cycle rely on the continuous, coordinated expansion and contraction of cells.. In order to accommodate these varied changes in cell morphology, the cell membrane that contains the cell must alter morphology as well. However, cell membranes are highly inelastic. Studies have shown that the maximum elastic stretching of a membrane is only 4%, even when the cell is subjected to lytic tensions which are 100 to ...
Cell membrane function in animal cell and plant cell. Cell membrane surrounds the cytoplasm and other organelles in it. Also, it controls the entry and exit of nutrients and other microscopic entities into the cell. In both animal and plant cell. The cell (from latin cella, meaning small room) is the basic structural, functional, and biological unit of all known organisms.a cell is the smallest unit of life. The ability to develop and grow The entire cell is surrounded by a membrane which is called the cell membrane. The cell membrane is also called plasma membrane or plasmalemma. It is a feature of all cells, both prokaryotic and eukaryotic. The cell membrane embraced owo layers of polysaccharide chains that are crosslinked with the assistance of dumpy peptide chains. The cell membrane, also known as the plasma membrane, is a double layer of lipids and proteins that surrounds a separates the cytoplasm (the contents of the cell) from the external environment. Functions of cell wall in ...
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Introduction. Transport across plasma membranes In this essay I will discuss and explain the transport across plasma membranes, to do this, I shall refer to osmosis, diffusion, facilitated diffusion, active transport and finally, exocytosis and endocytosis. Like all other cellular membranes, the plasma membrane consists of both lipids and proteins. The fundamental structure of the membrane is the phospholipid bilayer, which forms a stable barrier between two aqueous compartments. In the case of the plasma membrane, these compartments are the inside and the outside of the cell. Proteins embedded within the phospholipid bilayer carry out the specific functions of the plasma membrane, including selective transport of molecules. The diagram opposite shows the fluid The plasma membrane is a selectively permeable barrier between the cell and the extracellular environment. Its permeability properties ensure that essential molecules such as glucose, amino acids, and lipids are able to readily enter the ...
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Endocytosis is a fundamental process in signaling and membrane trafficking. The formation of vesicles at the plasma membrane is mediated by the G protein dynamin that catalyzes the final fission step, the actin cytoskeleton, and proteins that sense or induce membrane curvature. One such protein, the F-BAR domain-containing protein pacsin, contributes to this process and has been shown to induce a spectrum of membrane morphologies, including tubules and tube constrictions in vitro. Full-length pacsin isoform 1 (pacsin-1) has reduced activity compared to its isolated F-BAR domain, implicating an inhibitory role for its C-terminal Src homology 3 (SH3) domain. Here we show that the autoinhibitory, intramolecular interactions in pacsin-1 can be released upon binding to the entire proline-rich domain (PRD) of dynamin-1, resulting in potent membrane deformation activity that is distinct from the isolated F-BAR domain. Most strikingly, we observe the generation of small, homogenous vesicles with the activated
TY - JOUR. T1 - The economics of neurite outgrowth - The addition of new membrane to growing axons. AU - Futerman, Anthony H.. AU - Banker, Gary A.. PY - 1996/4. Y1 - 1996/4. N2 - Recent studies have shown that axonal growth is disrupted by treatments that block the synthesis of membrane components or their delivery by microtubule-based transport. This implies that a continuous supply of newly synthesized membrane components is necessary to sustain growth. In contrast, no clear consensus has yet been achieved about the site of insertion of new membrane components in the membrane of the growing axon, despite the application of new and refined biophysical and molecular techniques to the study of this issue. Until the site of insertion of new membrane components is resolved, little progress can be made in defining the feedback mechanisms by which the supply of new membrane components is co-ordinated with the demands of growth, particularly in cases where the dynamics of neurite growth change from ...
The membrane curvature can regulate the localization of proteins with specific recognition motifs. Amphipathic alpha helices are critical membrane curvature sensors with a large range of proteins included with larger affinity for positively curved membranes through the recognition of curve defects in lipid packing. The membrane curvature dependent measurements, mostly made in vitro, are averaged across liposomes of variant diameter. These measurements reduce the accuracy and make calculation of affinity more difficult ...
Fingerprint Dive into the research topics of High-Affinity Transport of L-Glutamine by a Plasma Membrane Preparation from Rat Brain. Together they form a unique fingerprint. ...
Amazing pictures of 5 Pictures Of Animal Cell Membrane is totally great for your biological science knowledge. The image Resolution 640 x 480 px and the image size only 66 kb. Click the thumbnail to see the larger version.. Tagged with: animal cell membrane, animal cell membrane color, animal cell membrane definition, animal cell membrane diagram, animal cell membrane function, .. ...
Monotopic proteins represent a specialized group of membrane proteins in that they are engaged in biochemical events taking place at the membrane interface. In particular, the monotopic lipid-synthesizing enzymes are able to synthesize amphiphilic lipid products by catalyzing two biochemically distinct molecules (substrates) at the membrane interface. Thus, from an evolutionary point of view, anchoring into the membrane interface enables monotopic enzymes to confer sensitivity to a changing environment by regulating their activities in the lipid biosynthetic pathways in order to maintain a certain membrane homeostasis. We are focused on a plant lipid-synthesizing enzyme DGD2 involved in phosphate shortage stress, and analyzed the potentially important lipid anchoring segments of it, by a set of biochemical and biophysical approaches. A mechanism was proposed to explain how DGD2 adjusts its activity to maintain a proper membrane. In addition, a multivariate-based bioinformatics approach was used ...
Plasma membrane(PM) protein accounts for a small fraction of total cellular protein in plants but performs a very critical role in plant physiology. Isolation and purification of PM protein from plant tissues have been traditionally done by sucrose density ultracentrifugation and aqueous two-phase partitioning. These methods, while relatively effective, require ultracentrifugation and large amount of starting material. The procedures are usually tedious and time consuming.To overcome the shortcomings, we have developed this PM isolation kit. Plant tissues are first sensitized by buffer A, homogenized, and pass through a specialized filter cartridge that allows homogenates to pass through with a zigzag path. The cell membranes are ruptured into a range of predefined size during the process. Native plasma membranes are separated from a mixture of un-ruptured cells, nuclei, cytosol and organelles by subsequent differential centrifugation and density centrifugation without using ...
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Physiology and structure of cell membrane depend on the proportion of lipids, proteins and carbohydrates. They change according to the cell type and membrane location. For example, plasma membrane of erythrocytes contain 50 % of lipids, 40 % of proteins and 10 % of carbohydrates. A similar composition is found in most of the plasma membranes of other cell types, with some exceptions. Myelin, cell membrane of glial cells that wraps axons, is composed of 80 % of lipids and 20 % of proteins, and almost no carbohydrates. Intracellular membranes usually show a higher proportion of proteins than plasma membrane. A remarkable example is the inner mitochondrial membrane, where proteins are up to 80 %. Furthermore, lipids, proteins, and carbohydrates are diverse, and membranes do not only differ in the proportion of these three molecular groups, but also in the different types of lipids, proteins, and carbohydrates that are present. Moreover, as mentioned above, membranes are continuously recycled, and ...
Question 4: [8 pts]Data for membrane mobility of three different proteins (X, Y, and Z) using fluorescent recovery afterphotobleaching (FRAP) are shown
Listing of the answers to the question: Proteins that are destined to become associated with the inner surface of the plasma membrane are:
To make use nuclear content doesnt release, you can take out serveral ul cells and stain with trypan blue. Cell with intact plasma membrane will appear as white and nucleas will appear as blue (coz prypan blue can stain nucleas but cannot pass through plasma membrane ...
DC-SIGN cell surface distribution during monocyte-derived DC development. DC-SIGN binding activity was monitored during development of monocyte-derived DCs. As
"The fluid mosaic model of the structure of cell membranes" in 1972,[5] which is now regarded as a classic paper in cell biology ... mainly cell membrane and organelle membranes (especially those of mitochondria), and this is important for maintaining stable ... It was the first model in cell biology to be based on thermodynamics properties. Earlier descriptions of the cell membrane had ... Garth L. Nicolson (born October 1, 1943)[1] is an American biochemist who made a landmark scientific model for cell membrane, ...
... plasmatic membrane (Pfeffer, 1900),[13] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[14][15] Some ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ... The basic function of the cell membrane is to protect the cell from its surroundings. The cell membrane controls the movement ... It was also inferred that cell membranes weren't vital components to all cells. Many refuted the existence of a cell membrane ...
Cell signaling: calcium signaling and calcium metabolism. Cell membrane. Ion pumps. *SERCA ... raise the magnitude of cell-averaged ICA-induced calcium transients and spontaneous calcium sparks in isolated heart cells.[4] ...
Membrane cell electrolysis employs permeable membrane as an ion exchanger. Saturated sodium (or potassium) chloride solution is ... "The membrane cell process". Euro Chlor. Archived from the original on 2011-11-11. Retrieved 2007-08-15.. ... "The diaphragm cell process". Euro Chlor. Archived from the original on 2011-11-11. Retrieved 2007-08-15.. ... In diaphragm cell electrolysis, an asbestos (or polymer-fiber) diaphragm separates a cathode and an anode, preventing the ...
Cells in each layer bound together cell-adhesion molecules, but no basement membranes except Homoscleromorpha.[16]. inter-cell ... Nerve cells. Sensory cells appear between or sometimes on top of the muscle cells,[9] and communicate via synapses (gaps across ... cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory ... Number of cells in middle "jelly" layer Many. Few. (Not applicable) Cells in outer layers can move inwards and change functions ...
Cell membrane protein disorders (other than Cell surface receptor, enzymes, and cytoskeleton) ... Among the methods thought to hold promise for treatment include gene transfer therapy,[13] which works by inserting in cells of ...
Elul, R.J. (1967). Fixed charge in the cell membrane.. *^ Yang, Jun; Lu, Fuzhi; Kostiuk, Larry W.; Kwok, Daniel Y. (1 January ... "Fixed charge in the cell membrane" (1967). Water electrokinetics[edit]. In October 2003, Dr. Daniel Kwok, Dr. Larry Kostiuk and ... where it was found to cause physical damage to neurons by inciting movement in their membranes.[7][8] It is discussed in R.J. ...
Cell membrane protein disorders (other than Cell surface receptor, enzymes, and cytoskeleton) ... Schwann cells create the myelin sheath, by wrapping its plasma membrane around the axon.[13] ... Neurons, Schwann cells, and fibroblasts work together to create a functional nerve. Schwann cells and neurons exchange ... X-linked CMT and Schwann cells[edit]. CMT can also be produced by X-linked mutations, and is named X-linked CMT (CMTX). In CMTX ...
Radicals alter blood cell membrane properties. This leads to blood cell aggregation and increased blood viscosity which results ... A buildup of glycated hemoglobin within the red cell, therefore, reflects the average level of glucose to which the cell has ... sickle-cell disease, or any other condition causing premature red blood cell death. Blood donation will result in rapid ... A1c is a weighted average of blood glucose levels during the life of the red blood cells (117 days for men and 106 days in ...
When the P. falciparum parasite infects a host cell, it alters the characteristics of the red blood cell membrane, making it " ... Sickle-cell[edit]. Main article: Sickle-cell anemia. See also: Sickle-cell trait and Evolutionary_baggage § Sickle-Cell and ... G6PD is present in all human cells but is particularly important to red blood cells. Since mature red blood cells lack nuclei ... hematopoietic (stem cell) - the blood stem cells that give rise to all other blood cells ...
Cell membrane protein disorders (other than Cell surface receptor, enzymes, and cytoskeleton) ...
plasma membrane. • cell cortex. • integral component of membrane. • azurophil granule membrane. • Z disc. • neuronal cell body ... synaptic membrane. • integral component of presynaptic membrane. • endosome. • early endosome membrane. • cell projection. ... Golgi membrane. • integral component of plasma membrane. • smooth endoplasmic reticulum. • lysosomal membrane. • cell junction ... cell surface. • membrane-bounded organelle. • endoplasmic reticulum. • membrane raft. • Golgi apparatus. • growth cone. • ...
"Epsin: inducing membrane curvature". The International Journal of Biochemistry & Cell Biology. 39 (10): 1765-70. doi:10.1016/j ... Epsins are a family of highly conserved membrane proteins that are important in creating membrane curvature. Epsins contribute ... "Seminars in Cell & Developmental Biology. 23 (4): 429-36. doi:10.1016/j.semcdb.2012.01.011. PMC 3507467 . PMID 22306180.. ... "The Plant Cell Online. 18 (9): 2258-2274. doi:10.1105/tpc.105.039123. PMC 1560928 .. ...
... s or haemolysins are lipids and proteins that cause lysis of red blood cells by disrupting the cell membrane. Although ... Protein: cell membrane proteins (other than Cell surface receptor, enzymes, and cytoskeleton) ... causes the degradation of phagosome membranes, but they are not a potential danger for the cell's plasmatic membrane. ... In nature, Staphylococcus aureus secretes alpha-hemolysin monomers that bind to the outer membrane of susceptible cells. Upon ...
For example, mGFP often refers to a GFP with an N-terminal palmitoylation that causes the GFP to bind to cell membranes. ... GFP-labelled cancer cells have been used to model metastasis, the process by which cancer cells spread to distant organs.[56] ... tracking of AMPA receptors on cell membranes,[48] viral entry and the infection of individual influenza viruses and lentiviral ... "Partitioning of lipid-modified monomeric GFPs into membrane microdomains of live cells". Science. 296 (5569): 913-16. Bibcode: ...
The B cell receptor (membrane bound antibody; BCR) is specific to the tTG portion of the complex. The B cell endocytoses the ... These T cells become activated and polarised into type I helper T (Th1) cells. Th1 cells reactive towards gliadin have been ... Once the B cell becomes activated, it differentiates into plasma cells that secrete autoantibodies against tTG, which may be ... Thus, the B cell presents the foreign peptide (modified gliadin) but produces antibodies specific for the self-antigen (tTG). ...
In: Cell physiology sourcebook: essentials of membrane biophysics. Amsterdam; Boston: Elsevier/AP, 2012. ... the basic physiological functions of cells can be divided into the processes of cell division, cell signaling, cell growth, and ... Cells[edit]. Main article: Cell physiology. Although there are differences between animal, plant, and microbial cells, ... a unified science of life based on the cell actions,[22] later renamed in the 20th century as cell biology.[30] ...
... and thus induces membrane hyperpolarization. As a result, sperm movement is activated.[3] The change in cell volume which ... Sperm motility in mammals also facilitates the passage of the sperm through the cumulus oophorus (a layer of cells) and the ...
Protein: cell membrane proteins (other than Cell surface receptor, enzymes, and cytoskeleton) ... integral component of membrane. • myelin. • plasma membrane. • membrane. Biological process. • axon ensheathment. • integrin- ... glial cell differentiation. • cell maturation. • long-chain fatty acid biosynthetic process. • substantia nigra development. • ... 2008). "Novel MITF targets identified using a two-step DNA microarray strategy". Pigment Cell Melanoma Res. 21 (6): 665-76. doi ...
Protein: cell membrane proteins (other than Cell surface receptor, enzymes, and cytoskeleton) ... by glial cells called Schwann cells. In the CNS, axons carry electrical signals from one nerve cell body to another. In the PNS ... In the CNS, cells called oligodendrocyte precursor cells (OPCs; the precursors of oligodendrocytes) differentiate into mature ... a limb-like extension from the cell body) around the axon.[2][3] Myelin reduces the capacitance of the axonal membrane. On a ...
These channels are expressed on the cell membrane. CLC channels contribute to the excitability of these membranes as well as ... Voltage-gated chloride channels are important for setting cell resting membrane potential and maintaining proper cell volume. ... 2 cells". Plant Cell Environ. 29 (6): 1122-37. doi:10.1111/j.1365-3040.2005.01487.x. PMID 17080938. CS1 maint: Uses authors ... cell migration, cell proliferation and differentiation. Based on sequence homology the chloride channels can be subdivided into ...
Most of these toxins degrade the cell membrane. There are potentially interesting applications of killer isolates in medicine, ... cell-to-cell movement' proteins. It is therefore assumed that mycoviruses only move intercellularly during cell division (e.g. ... Killer isolates secrete proteins that are toxic to sensitive cells of the same or closely related species while the producing ...
Too strong or too weak a solution may damage the membranes. Membrane cells typically produce caustic in the range of 30% to 33 ... the Hargreaves-Bird cell (1901), the Gibbs cell (1908), and the Townsend cell (1904). The cells vary in construction and ... The building that houses the many electrolytic cells is usually called a cell room or cell house, although some plants are ... The electrolysis cell is divided into two "sections" by a cation permeable membrane acting as a cation exchanger. Saturated ...
Internal cell structure. No membrane-bound organelles or nucleus. No membrane-bound organelles or nucleus. Membrane-bound ... Further information: Cell wall § Archaeal cell walls. Most archaea (but not Thermoplasma and Ferroplasma) possess a cell wall.[ ... Like bacteria, archaea lack interior membranes and organelles.[52] Like bacteria, the cell membranes of archaea are usually ... Diagrammatic view of Methanobrevibacter smithii, showing the cell membrane (ochre, with inset) and cell wall (purple). ...
The basement membrane controls the traffic of the cells and molecules between the dermis and epidermis but also serves, through ... Keratinocytes are the major cells, constituting 95% of the epidermis,[9] while Merkel cells, melanocytes and Langerhans cells ... Sonic hedgehog-expressing epidermal cells induce the condensation of cells in the mesoderm. The clusters of mesodermal cells ... Basement membrane[edit]. Main article: Basement membrane. The epidermis and dermis are separated by a thin sheet of fibers ...
July 2005). "Crystal structure of mitochondrial respiratory membrane protein complex II". Cell. 121 (7): 1043-57. doi:10.1016/j ... "Crystal structure of mitochondrial respiratory membrane protein complex II". Cell. 121 (7): 1043-57. doi:10.1016/j.cell. ... found in many bacterial cells and in the inner mitochondrial membrane of eukaryotes. It is the only enzyme that participates in ... Around SdhC and SdhD is a phospholipid membrane with the intermembrane space at the top of the image.[4] ...
Live cells or tissues with intact cell membranes are not coloured. Since cells are very selective in the compounds that pass ... in a viable cell trypan blue is not absorbed; however, it traverses the membrane in a dead cell. Hence, dead cells appear as a ... Since live cells are excluded from staining, this staining method is also described as a dye exclusion method. This dye may be ... Strober, W (May 2001). Trypan blue exclusion test of cell viability. Current Protocols in Immunology. Appendix 3. pp. Appendix ...
"Crystal structure of mitochondrial respiratory membrane protein complex II". Cell. 121 (7): 1043-57. doi:10.1016/j.cell.2005.05 ... mitochondrial inner membrane. • mitochondrion. • mitochondrial membrane. • respiratory chain complex II. Biological process. • ... "Cell-permeating alpha-ketoglutarate derivatives alleviate pseudohypoxia in succinate dehydrogenase-deficient cells". Mol. Cell ... membrane. • plasma membrane. • nucleoplasm. • mitochondrial respiratory chain complex II, succinate dehydrogenase complex ( ...
... "cell membrane". The term sarcolemma refers specifically to the cell membrane of muscle cells and not to the membrane of ... By contrast, the terms "cell membrane" refers generically to the cell membrane of any kind of cells that could be targeted by ... Molecular and Cell BiologyWikipedia:WikiProject Molecular and Cell BiologyTemplate:WikiProject Molecular and Cell BiologyMCB ... a one cell animal commonly found in the human intestine) and mammalian cells originally obtained from the abdomen of small ...
Boldyrev, A. A. (2000). "Na+,K+-ATPase: 40 years of investigations". Membrane & Cell Biology. 13 (6): 715-9. PMID 10963431. ... He therefore had the idea of looking at an enzyme which was embedded in the membrane and finding out if its properties were ... Post had recently discovered that three sodium ions were pumped out of the cell for every two potassium ions pumped in, and in ... Skou, J. C. (1989). "The identification of the sodium-pump as the membrane-bound Na+/K+-ATPase: a commentary on 'The Influence ...
Another bile acid receptor is the cell membrane receptor known as G protein-coupled bile acid receptor 1 or TGR5. Many of their ... Cell signallingEdit. Bile acids have metabolic actions in the body resembling those of hormones, acting through two specific ... Bile acid synthesis occurs in liver cells, which synthesize primary bile acids (cholic acid and chenodeoxycholic acid in humans ... Exposure of colonic cells to high DCA concentrations increase formation of reactive oxygen species, causing oxidative stress, ...
Other organelles in a plasma cell include ribosomes, lysosomes, mitochondria, and the plasma membrane. ... Plasma cells, also called plasma B cells, plasmocytes, plasmacytes, or effector B cells, are white blood cells that secrete ... In humans, CD27 is a good marker for plasma cells, naive B cells are CD27-, memory B-cells are CD27+ and plasma cells are ... Germinal center B cells may differentiate into memory B cells or plasma cells. Most of these B cells will become plasmablasts ( ...
... and membrane association in COS cells". Proc. Natl. Acad. Sci. U.S.A. 87 (2): 728-32. doi:10.1073/pnas.87.2.728. PMC 53339 . ... Cell. Biochem. 204 (1-2): 135-55. doi:10.1023/A:1007012622030. PMID 10718634. Geyer M, Fackler OT, Peterlin BM (2001). " ... Zhou W, Parent LJ, Wills JW, Resh MD (1994). "Identification of a membrane-binding domain within the amino-terminal region of ... Zhou W, Resh MD (1997). "Differential membrane binding of the human immunodeficiency virus type 1 matrix protein". J. Virol. 70 ...
M phase of mitotic cell cycle. · mitotic prophase. · mitotic anaphase. · mitotic cell cycle. · apoptotic process. · cellular ... 核纖層是真核生物细胞核中附于内核膜(英语:inner nuclear membrane)内侧的网络片层结构。其核纤层蛋白家族在进化中高度保守。在有絲分裂过程中,核纤层蛋白磷酸化,核纖層解聚(这一过程是可逆的)。Lamin蛋白質被認為與細胞核的穩定性、染色 ... Lamin A is targeted to the nuclear membrane by
VEGF-B treatment of hepatoma carcinoma cells can cause α-catenin to move from its normal location on the membrane into the ... F9 embryonal carcinoma cells are similar to the P19 cells shown in Figure 1 and normally have cell-to-cell adhesion mediated by ... A tumor cell line with defective δ-catenin, low levels of E-cadherin and poor cell-to-cell adhesion could be restored to normal ... providing the cell with a means of stable cell adhesion. However, decreases in this adhesion ability of the cell has been ...
This method is commonly used to separate organelles and membranes found in cells. Organelles generally differ from each other ... Cells are homogenised in a blender and filtered to remove debris. *The homogenised sample is placed in an ultracentrifuge and ... General method of fractionation: Cell sample is stored in a suspension which is: *Buffered - neutral pH, preventing damage to ... The ribosomes, membranes and Golgi complexes can be separated by another technique called density gradient centrifugation. ...
In all cells, the cell membrane separates the cytoplasm inside the cell from its surroundings. Animal cells are contained in ... The cell membrane is a thin flexible layer around the cells of all living things. It is sometimes called the plasma membrane or ... Cell membrane. biological membrane that separates the interior of a cell from its outside environment ... Other proteins and lipids can be added to the cell membrane. By these changes, the cell can adjust what it brings in or puts ...
cell proliferation. •organ morphogenesis. •extracellular matrix organization. •regulation of actin filament polymerization. • ... maternal single nucleotide polymorphisms in candidate genes that predispose to spontaneous preterm labor with intact membranes ... Bax DV, Rodgers UR, Bilek MM, Weiss AS (2009). «Cell adhesion to tropoelastin is mediated via the C-terminal GRKRK motif and ... Bertram C, Hass R (2009). «Cellular senescence of human mammary epithelial cells (HMEC) is associated with an altered MMP-7/HB- ...
The element is known to damage cell membranes of water animals, causing several negative influences on reproduction and on the ... The high radioactivity of lawrencium would make it highly toxic to living cells, causing radiation poisoning. The same is true ... The radioactivity of the actinides generally makes them highly toxic to living cells, causing radiation poisoning. ...
EBOV is thought to infect humans through contact with mucous membranes or skin breaks.[54] After infection, endothelial cells ( ... dendritic cells and other cells including liver cells, fibroblasts, and adrenal gland cells.[93] Viral replication triggers ... doi:10.1016/j.cell.2014.10.006. PMC 4243531. PMID 25417101.. *^ a b c d e f g h Kühl A, Pöhlmann S (September 2012). "How Ebola ... liver cells, and several types of immune cells such as macrophages, monocytes, and dendritic cells are the main targets of ...
"Cell. 136 (2): 272-83. doi:10.1016/j.cell.2008.11.047. PMC 2859625. PMID 19167329.. ... Oligosaccharyltransferase or OST (EC is a membrane protein complex that transfers a 14-sugar oligosaccharide from ... "J. Cell Biol. 161 (4): 715-25. doi:10.1083/jcb.200301043. PMC 2199356. PMID 12756234.. ... Yeast OST is composed of eight different membrane-spanning proteins in three subcomplexes (one of them is OST4).[7][8] These ...
It also contains pacemaker cells and nonpacemaker cells that initiate spontaneous breathing. Research is being conducted on the ... Unlike the fast and transient sodium current, the persistent sodium current (INaP) is activated at very low membrane potentials ... It is one of the four cell groups of the Ventral Respiratory Group (VRG). It is hypothesized that the pre-Bötzinger complex is ... Rhythmogenesis, the generation of rhythm, is modulated by membrane properties and synaptic interactions occurring in ...
Conjugated polyene fatty acids as membrane probes: preliminary characterization. Proc. Natl. Acad. Sci. U.S.A., 1975, 72. vsk, ... Cornelius AS, Yerram NR, Kratz DA, Spector AA: Cytotoxic effect of cis-parinaric acid in cultured malignant cells. Cancer Res. ...
membrane. • synapse. • integral component of plasma membrane. • chloride channel complex. • cell junction. • plasma membrane. • ... integral component of membrane. • GABA-A receptor complex. • postsynaptic membrane. • ... integral component of postsynaptic specialization membrane. • dendrite membrane. • neuron projection. • postsynapse. Biological ... This membrane protein-related article is a stub. You can help Wikipedia by expanding it.. *v ...
Because the cell acquiring a chloroplast already had mitochondria (and peroxisomes, and a cell membrane for secretion), the new ... though many secondary plastids are bounded by an outermost membrane derived from the host's cell membrane, and therefore ... The translocon on the outer chloroplast membrane (TOC)Edit. The TOC complex, or translocon on the outer chloroplast membrane, ... The translocon on the inner chloroplast membrane (TIC)Edit. The TIC translocon, or translocon on the inner chloroplast membrane ...
... and Th1 cells.[45] IL-1α stimulates increased skin cell activity and reproduction, which, in turn, fuels comedo development.[45 ... and accumulation of skin cells in the hair follicle.[1] In healthy skin, the skin cells that have died come up to the surface ... the increased production of oily sebum causes the dead skin cells to stick together.[10] The accumulation of dead skin cell ... The retinoids appear to influence the cell life cycle in the follicle lining. This helps prevent the accumulation of skin cells ...
The CD20 proteins are sticking out of the cell membrane, and rituximab, the Y-shaped antibody, is binding to the CD20 proteins. ... cells in destroying these B cells. When an NK cell latched onto the cap, it had an 80% success rate at killing the cell. In ... The antibody binds to the cell surface protein CD20. CD20 is widely expressed on B cells, from early pre-B cells to later in ... It induces apoptosis of CD20+ cells.. The combined effect results in the elimination of B cells (including the cancerous ones) ...
Basu et al (2014) Intestinal cell proliferation and senescence is regulated by receptor guanylyl cyclase C and p21 J. Biol. ... The Solvent-Exposed C-Terminus of the Cytolysin A Pore-Forming Toxin Directs Pore Formation and Channel Function in Membranes. ... the Alliance for Cell Signalling[20] (1997-present), the TB Structural Genomics Consortium, the American Society for ... Indian Society of Cell Biology[19] (1995-present) and the Society of Research in Reproduction, India (1994-present). ...
The endoplasmic reticulum is in cells that have a nucleus: in eukaryote cells but not in prokaryote cells. It takes these forms ... The lacey membranes of the endoplasmic reticulum were first seen in 1945 by scientists using an electron microscope.[2] ... Similar to the ER is the sarcoplasmic reticulum (SR) found only in muscle cells. The SR stores and pumps calcium ions. The SR ... Porter K.R; Claude A. & Fullam E.F. (1945). "A study of tissue culture cells by electron microscopy". J Exp Med. 81 (3): 233- ...
Outer hair cells serve as acoustic amplifiers for stimulation of the inner hair cells. Outer hair cells respond primarily to ... Synthetic membrane earphone[edit]. Modern technology seeks to minimize or prevent listener fatigue entirely. Blockage of the ... "J. Cell Biol. 164 (6): 887-97. doi:10.1083/jcb.200310055. PMC 2172292. PMID 15024034.. ... The stereocilia (hair cells) of the inner ear can become subjected to bending from loud noises. Because they are not ...
The German Type 214 submarine employs advanced polymer electrolyte membrane fuel cells that assist in delivering it comparable ... ...
In some barnacles, the cement glands are fixed to a long, muscular stalk, but in most they are part of a flat membrane or ... Such barnacles feed by extending thread-like rhizomes of living cells into their hosts' bodies from their points of attachment. ... Similarly, they have no gills, absorbing oxygen from the water through their limbs and the inner membrane of their carapaces. ... degrading to the condition of nothing more than sperm-producing cells.[15] ...
integral component of membrane. • membrane. • GO:0005578 extracellular matrix. • plasma membrane. • extracellular region. • ... Cell. 143 (3): 404-15. doi:10.1016/j.cell.2010.09.041. PMID 20970175. S2CID 18583237.. PDB: 3NK3​ PDB: 3NK4​ ... Cell. 143 (3): 404-15. doi:10.1016/j.cell.2010.09.041. PMID 20970175. S2CID 18583237.. PDB: 3NK3, 3NK4​ ... Cell. Biol. 22 (9): 3111-20. doi:10.1128/MCB.22.9.3111-3120.2002. PMC 133755. PMID 11940668.. ...
Polymorphonuclear cells also infiltrate the epithelium, and chronic inflammatory cells infiltrate the lamina propria. Atrophic ... That is, oral candidiasis is a mycosis (yeast/fungal infection) of Candida species on the mucous membranes of the mouth. ... Apart from true hyphae, Candida can also form pseudohyphae - elongated filamentous cells, lined end to end. As a general rule, ... It may precede the formation of a pseudomembrane, be left when the membrane is removed, or arise without prior pseudomembranes ...
Its receptor - the neurokinin type 1 - is distributed over cytoplasmic and nuclear membranes of many cell types (neurons, glia ... Substance P has been known to stimulate cell growth in normal and cancer cell line cultures,[37] and it was shown that ... "Substance P induces rapid and transient membrane blebbing in U373MG cells in a p21-activated kinase-dependent manner". PLOS ONE ... on cells (including cancer cells) bestowing upon them mobility.[40] and metastasis.[41] It has been suggested that cancer ...
ଲୋହିତ ରକ୍ତ କଣିକା ନିଜର ଜୀବନ‌କାଳ(୧୨୦ ଦିନ) ସମାପ୍ତ କରିସାରିଲେ ବା କୌଣସି କାରଣରୁ ନଷ୍ଟ ହେଲେ ତାହାର କୋଷ ପରଦା(cell membrane) ଭଙ୍ଗୁର ହୋଇ ... ଅଧିକ ଅନ‌କଞ୍ଜୁଗେଟେଡ ବିଲିରୁବିନ ହେବାର କାରଣ: ହେମୋଲାଇଟିକ ଆନିମିଆ (excess red blood cell breakdown), ବିରାଟ ଅଧଃକ୍ଷତ (large bruise), ...
The skin consists of a thin outer epidermis with mucous cells and sensory cells, and a connective tissue dermis consisting ... which is mostly suspended from the roof of the mantle cavity by numerous membranes. The tract consists of a crop, where the ... Other colour-changing cells are reflective iridophores and white leucophores.[93] This colour-changing ability is also used to ... The lens is suspended behind the pupil and photoreceptive retinal cells cover the back of the eye. The pupil can be adjusted in ...
Role of the swarmer cell stageEdit. The Caulobacter stalked cell stage provides a fitness advantage by anchoring the cell to ... Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, and the ... Swarmer cells differentiate into stalked cells after a short period of motility. Chromosome replication and cell division only ... What is the offsetting fitness advantage of this motile cell stage? The swarmer cell is thought to provide cell dispersal, so ...
Stacks of membrane-enclosed disks are unattached to cell membrane directly Disks are attached to outer membrane ... To be more specific, photoreceptor proteins in the cell absorb photons, triggering a change in the cell's membrane potential. ... Further complexity arises from the various interconnections among bipolar cells, horizontal cells, and amacrine cells in the ... The positive charges of the ions that enter the cell down its electrochemical gradient change the cell's membrane potential, ...
Several cells may live together, forming filaments (or colonies). Andres 09:28, 11 Aug 2004 (UTC). *If someone knows more (or ... have a common outer membrane. Basa 16:31, 19 January 2007 (UTC) ... In a colony, a term quite loosely defined, the cells are stuck ... the nitrogen-fixing protein complex may be packaged into specialized cells called heterocysts." Aren't bacteria single-celled? ... Does specialized "cells" mean something like organelles? This all seems to contradict my limited knowledge of biology. ...
... plasmatic membrane (Pfeffer, 1900),[13] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[14][15] Some ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ... The basic function of the cell membrane is to protect the cell from its surroundings. The cell membrane controls the movement ... It was also inferred that cell membranes werent vital components to all cells. Many refuted the existence of a cell membrane ...
... plasmatic membrane (Pfeffer, 1900),[15] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[16][17] Some ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ... It was also inferred that cell membranes were not vital components to all cells. Many refuted the existence of a cell membrane ... side of the cell membrane, acting as enzymes shaping the cell.[3] The cell membrane controls the movement of substances in and ...
Cell - Membrane lipids: Membrane lipids are principally of two types, phospholipids and sterols (generally cholesterol). Both ... Some glycoproteins are involved in cell-to-cell recognition (see below The cell matrix and cell-to-cell communication). ... Membrane fluidity. One of the triumphs of cell biology during the decade from 1965 to 1975 was the recognition of the cell ... The cell matrix and cell-to-cell communication*The extracellular matrix*Matrix polysaccharides ...
... everything you need for studying or teaching Cell membrane. ... Immediately download the Cell membrane summary, chapter-by- ... Membrane Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the ... Cell membrane Summary. Everything you need to understand or teach Cell membrane. ... Membrane Structure Surrounding each cell within the nervous system is a highly complex lipid bilayer called a membrane formed ...
Cell Membranes Paul Andersen explains how cells are selectively permeable with the help of their cell membrane. The main ... 015 - Cell Membranes. Paul Andersen explains how cells are selectively permeable with the help of their cell membrane. The main ... Insights into cell membranes via dish detergent - Ethan Perlstein - Duration: 3:50. TED-Ed 124,904 views ... The cell wall in plants, bacteria, and fungi is also discussed.. Intro Music Atribution. Title: I4dsong_loop_main.wav. Artist: ...
... This site includes an animated presentation of the cell membrane that walks users through the structure ... You just viewed Animated Cell Membrane. Please take a moment to rate this material. ... It is an animation that is put together very well and provides a nice visualization of molecular components found in the cell ...
Cell - Transport across the membrane: The chemical structure of the cell membrane makes it remarkably flexible, the ideal ... Yet the membrane is also a formidable barrier, allowing some dissolved substances, or solutes, to pass while blocking others. ... Lipid-soluble molecules and some small molecules can permeate the membrane, but the lipid bilayer effectively repels the many ... large, water-soluble molecules and electrically charged ions that the cell must import or export in order to live. Transport of ...
... membrane selectively permeable phospholipids bilayer proteins transmembrane (integral) proteins peripheral proteins transport ... Cellmembrane concept map words * 1. cell (plasma) membrane selectively permeable phospholipids bilayer proteins transmembrane ( ...
Source for information on Cell Membranes: Gale Encyclopedia of Nursing and Allied Health dictionary. ... also known as a plasma membrane) is a thin semifluid structure that separates the contents of a cell or organelle from its ... Cell Membranes. Definition. A cell membrane (also known as a plasma membrane) is a thin semifluid structure that separates the ... muscle cells) and adipocytes (fat cells). The glucose transporter GluT4 is normally present in the cell membrane in small ...
2. Cell membranes consist of a double layer of what?. 3. Name the types of molecules in the cell membrane and the three ... What do animal membranes have that plant membranes do not?. Identify and build your own cell membrane using the website. ... Construction of the Cell Membrane Worksheet. Directions: Use the website Construction of the Cell Membrane (http://www.wisc- ... Construction of the Cell Membrane. Date last modified:. December 6, 2004. Created by:. Jill Sackett. License:. ...
... the membrane is the inner layer of protection surrounded by a rigid cell wall. Eukaryotic animal cells have only the membrane ... These membranes also regulate the passage of molecules in and out of the cells. ... All living cells have a plasma membrane that encloses their contents. In prokaryotes, ... Plasma Membrane. All living cells, prokaryotic and eukaryotic, have a plasma membrane that encloses their contents and serves ...
This membrane work is a critical part of a larger overall effort at UD to make platinum-free fuel cells a commercial reality ... Better fuel cell membranes. Article by Diane Kukich Photo by Kathy F. Atkinson September 15, 2016 ... "Our goal is to develop a process to easily synthesize the polymer at scale, creating large area membranes for testing that are ... He and colleagues recently reported a breakthrough that promises to bring down the cost of hydrogen fuel cells by replacing ...
Phosphoinositides in cell regulation and membrane dynamics.. Di Paolo G1, De Camilli P. ... Their functions, besides classical signal transduction at the cell surface, include regulation of membrane traffic, the ... Department of Pathology and Cell Biology, The Taub Institute for Research on Alzheimers Disease and the Aging Brain, Columbia ... Inositol phospholipids have long been known to have an important regulatory role in cell physiology. The repertoire of cellular ...
The cell membrane is one of the most important components of a cell because it separates the interior from the environment and ... controls the movement of substances in and out of the cell. In a move that brings mankind another step closer to be... ... "The cell membrane is one of the most important components of a cell because it separates the interior from the environment and ... UCSD Researchers Create Artificial Cell Membrane 54 Posted by Unknown Lamer on Tuesday January 31, 2012 @04:11AM. from the sr- ...
... and they continue to strengthen our understanding of this essential aspect of cell structure and function. ... Membrane and organelle assembly has emerged as a dominant theme in cell biology of the twenty-first century. Current approaches ... Merging cultures in the study of membrane traffic. *Randy Schekman1. Nature Cell Biology volume 6, pages483-486(2004)Cite this ... Membrane and organelle assembly has emerged as a dominant theme in cell biology of the twenty-first century. Current approaches ...
doi: 10.1016/j.cell.2018.09.054. Epub 2018 Nov 1. Research Support, N.I.H., Extramural; Research Support, Non-U.S. Govt; ... doi: 10.1016/j.cell.2018.09.054. Epub 2018 Nov 1.. Cell Membranes Resist Flow.. Shi Z1, Graber ZT2, Baumgart T2, Stone HA3, ... B) Simple viscoelastic model of the cell membrane. Springs represent the elastic response of the membrane to stretch, and ... It is widely assumed that membrane flow transmits local changes in membrane tension across the cell in milliseconds, mediating ...
Membranes have played increasingly important roles in fuel cells. For fuel cells, membranes are involved in fuel processing and ... 180oC and new membranes for alkaline fuel cells, are critical to the widespread use of fuel cells. Original and review papers ... the performance of fuel cell on the cathode side. Proton-exchange and hydroxyl ion-exchange membranes and membrane electrode ... proton-exchange membranes, (3) hydroxyl ion-exchange membranes, and (4) membrane electrode assemblies. We will include papers ...
They obstruct the development of bacterial cells by preventing bacteria from forming the cell ... Read ,. Author: Aaron Smith ... the tree-like antennae that are found on cell membrane in the body). However, the term glyconutrient is a term... Read ,. ...
The cell membrane (or plasma membrane) is the thin outer layer of the cell that differentiates the cell from its environment. ... Cell membranes of nerve cells, muscle cells, and some eggs are excitable electrically. In nerve cells, for example, the plasma ... Other functions of cell membranes. *Organization. Some receptors on the external surface of the cell membrane participate in ... Transport across the cell membrane. As the cell membrane is semi-permeable, only some molecules can pass unhindered into or out ...
Microbial Cell Biology. Membrane Topology and Identification of Critical Amino Acid Residues in the Wzx O-Antigen Translocase ... Impact of Membrane Phospholipid Alterations in Escherichia coli on Cellular Function and Bacterial Stress Adaptation Veronica W ... pqiABC and yebST, Putative mce Operons of Escherichia coli, Encode Transport Pathways and Contribute to Membrane Integrity ... The KtrA and KtrE Subunits Are Required for Na+-Dependent K+ Uptake by KtrB across the Plasma Membrane in Synechocystis sp. ...
... plasmatic membrane (Pfeffer, 1900),[13] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[14][15] Some ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ... It was also inferred that cell membranes werent vital components to all cells. Many refuted the existence of a cell membrane ... requiring the cell to expend energy in transporting it. The membrane also maintains the cell potential. The cell membrane thus ...
... plasmatic membrane (Pfeffer, 1900),[14] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[15][16] Some ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ... It was also inferred that cell membranes werent vital components to all cells. Many refuted the existence of a cell membrane ... side of the cell membrane acting as several kinds of enzymes shaping the cell , respectively.[3] The cell membrane controls the ...
Myosin IIA interacts with the spectrin-actin membrane skeleton to control red blood cell membrane curvature and deformability ... Enhanced Membrane Fluctuations in the Presence of ATP.. To probe dynamic membrane fluctuations, we analyzed the membrane ... Metabolic remodeling of the human red blood cell membrane. YongKeun Park, Catherine A. Best, Thorsten Auth, Nir S. Gov, Samuel ... Metabolic remodeling of the human red blood cell membrane. YongKeun Park, Catherine A. Best, Thorsten Auth, Nir S. Gov, Samuel ...
Cells membrane synonyms, Cells membrane pronunciation, Cells membrane translation, English dictionary definition of Cells ... n. The semipermeable membrane that encloses the cytoplasm of a cell. Also called cytomembrane , plasmalemma , plasma membrane ... Related to Cells membrane: plasma membrane, fluid mosaic model. cell membrane. n.. The semipermeable membrane that encloses ... cell membrane - a thin membrane (a double layer of lipids) enclosing the cytoplasm of a cell; proteins in the membrane control ...
Methods and compositions are provided for the persistent modification of cell membranes with exogenous proteins so as to alter ... the function of the cell to achieve effects similar to those of gene therapy, without the introduction of exogenous DNA. DNA ... "Cell surface" has its normal meaning in the art, comprising the phospholipid bilayer of a cell membranes and the molecules ... This invention relates to the persistent modification of cell membranes so as to alter the function of the cells. The ...
Or log in to play for credit.. This activity is tracked by Mr. Charles Ippolito. If you are in Mr. Charles Ippolitos class, please log in for credit:. ...
Several studies have indicated that the cell surface could play an important role in the control of cell cycle, growth, ... Sapora O., Parasassi T., Padovani L.M., Conti F. (1985) Membrane Fluorescence Anisotropy Behavior during Cell Cycle. In: Conti ... Several studies have indicated that the cell surface could play an important role in the control of cell cycle, growth, ... C. L. Mummery, J. Booustra, P. Van der Saag, and S. W. De Laat, J.Cell Physiol., 107: 1 (1981).PubMedCrossRefGoogle Scholar ...
Electron microscopy of cell membranes. Br Med J 1978; 1 doi: (Published 17 June 1978) ...
Membranes surround and protect all of our cells, and their organelles, including the mitochondria - the powerhouse of the cell ... These membranes contain protein complexes that allow molecules to move in and out of cells. Whilst some of those molecules can ... New way to look at cell membranes could change the way we study disease. Published: 22 November 2018 ... I wasnt sure this would ever work; I thought the membrane environment would be just too complicated and we wouldnt be able to ...
Expose intact cell to protease.. *Expose intact cell with detergent (to release proteins from the cell membrane) and protease. ... If you expose an intact cell to a protease enzyme, you can shave off the protein found on the outside of the cell. If the cell ... Membrane Structure Dynamics[edit]. Membrane proteins are asymmetrically placed and fixed in the membrane so that one side is ... This experiment shows where the proteins are embedded or attached to the membrane. Real cells have more than 5 membrane ...
  • This type of lipid bilayer, formed by the self-assembly of lipid molecules, is the basic structure of the cell membrane . (
  • Membrane Structure Surrounding each cell within the nervous system is a highly complex lipid bilayer called a membrane formed by microscopic phospholipid molecules. (
  • Membrane Fluidity The membranes of bacteria function to give the bacterium its shape, allow the passage of molecules from the outside in and from the inside out, and to prevent the internal contents f. (
  • Lipid-soluble molecules and some small molecules can permeate the membrane, but the lipid bilayer effectively repels the many large, water-soluble molecules and electrically charged ions that the cell must import or export in order to live. (
  • The rates at which biologically important molecules cross the cell membrane through permeation vary over an enormous range. (
  • Large sugar molecules in the solution cannot pass through the membrane into the water (top). (
  • In contrast, small water molecules easily diffuse through the membrane (bottom). (
  • Outside the cell, water-soluble ions and molecules create a harsh and toxic environment. (
  • It acts as a gate, controlling the flow of molecules in and out of the cell. (
  • Plasma and organelle membranes are composed primarily of lipids (fatty acids, sterols, or other water-insoluble molecules) and proteins (chains of amino acids). (
  • Thus the membrane forms a stable yet flexible configuration with a certain amount of fluidity: individual phospholipids can move rapidly across the surface of the membrane, and part to allow molecules soluble in organic media (e.g., other lipids, dissolved gases, etc.) to enter the cell. (
  • Although some lipid-soluble molecules can permeate the cell membrane, many of the nutrients that a cell needs to function are too large to readily enter the cell. (
  • Transporters allow the cell to be selective in which molecules it allows into its cytoplasm. (
  • Examples of transporters are channels, which facilitate free movement of molecules across the membranes, and pumps, which require a certain amount of energy in order to transport molecules. (
  • The cell is constantly bombarded by ions and molecules of different type and size. (
  • While lipid-soluble molecules can pass readily through the membrane, water-soluble and larger particles require another mode of entry. (
  • Only lipid-soluble molecules and some small particles (e.g., biologically important gases such as oxygen and nitrogen) can readily permeate the cell membrane. (
  • Passive transport or facilitated diffusion occurs when water-soluble molecules and ions move through the membrane with the help of transporters (also called permeases). (
  • The student will study the structure of the cell membrane by constructing it using the correct molecules. (
  • 3. Name the types of molecules in the cell membrane and the three examples of globular-shaped proteins. (
  • 7. How do water molecules pass through the membrane? (
  • The plasma membrane is permeable to specific molecules, however, and allows nutrients and other essential elements to enter the cell and waste materials to leave the cell. (
  • Small molecules, such as oxygen, carbon dioxide, and water, are able to pass freely across the membrane, but the passage of larger molecules, such as amino acids and sugars, is carefully regulated. (
  • Others function as receptors, which bind information-providing molecules, such as hormones, and transmit corresponding signals based on the obtained information to the interior of the cell. (
  • Since the 1970s, the plasma membrane has been frequently described as a fluid mosaic , which is reflective of the discovery that oftentimes the lipid molecules in the bilayer can move about in the plane of the membrane. (
  • However, depending upon a number of factors, including the exact composition of the bilayer and temperature, plasma membranes can undergo phase transitions which render their molecules less dynamic and produce a more gel-like or nearly solid state. (
  • Cells are able to regulate the fluidity of their plasma membranes to meet their particular needs by synthesizing more of certain types of molecules, such as those with specific kinds of bonds that keep them fluid at lower temperatures. (
  • The cell membrane is composed mainly of phospholipid and protein molecules arranged in organized but flexible sheets. (
  • The phospholipid components form a bilayer that contributes structural stability and creates the semi-permeable environment, while the proteins are responsible for most of the dynamic processes carried out by cell membranes, such as the transport of molecules into and out of the cell. (
  • The three major types of lipids found in the cell membrane are phospholipids, glycolipids, and cholesterol molecules. (
  • They are crucial in recognizing specific molecules or other cells. (
  • During the secretion process, a sac, or vesicle, containing a cargo of molecules inside a cell moves to the cell's membrane and fuses with it. (
  • These membranes contain protein complexes that allow molecules to move in and out of cells. (
  • This new research, published in Science , has shown that protein complexes can be introduced into the mass spectrometer - an instrument to analyse molecules - straight from the natural membrane. (
  • Understanding protein complexes, and in particular how they are able to move other molecules across biological membranes is key to developing new therapeutics for a wide range of diseases. (
  • they also revealed how they communicate with each other, are guided into their correct position within the membrane, and how they transport other molecules. (
  • Given we still know so little about the movement of molecules in and out of cellular compartments that are bounded by membranes, these exciting developments in mass spectrometry will lead to a wealth of new information, that has not been previously accessible. (
  • There is a pressing need to better understand the complex lipid bilayer that makes up this membrane, which limits the molecules that can leave or enter the cell. (
  • Research into the plasma membrane structure and behavior can provide invaluable information about whether, and to what extent, small molecules such as sugars, hormones and drugs, can permeate. (
  • Depending on their concentration, sterol molecules can enhance membrane fluidity or increase its rigidity. (
  • The researchers used molecular dynamics computer simulations to simulate the structure and dynamics of the complex lipid membrane, which used Newton's equations of motion to understand how molecules move in response to forces generated by atomic interactions. (
  • [1] It contains a wide variety of biological molecules, primarily proteins and lipids, which are involved in a vast array of cellular processes, and also serves as the attachment point for both the intracellular cytoskeleton and, if present, the cell wall . (
  • According to the fluid mosaic model of S. J. Singer and Garth Nicolson, the biological membranes can be considered as a two-dimensional liquid where all lipid and protein molecules diffuse more or less freely [2] . (
  • The bilayer closest to the cytoplasm, or the outer mitochondrial membrane ( OMM , not Om Nom Nom ), has integral proteins called porins that allow small molecules to pass freely into the mitochondria. (
  • These molecules do not get very far, though, because they soon encounter the second bilayer , or inner mitochondrial membrane (IMM) . (
  • As you may, and should, recall from the section on mitochondria, these organelles are chiefly responsible for converting the chemical energy in macromolecules, like glucose , into molecules of ATP , adenosine triphosphate, that can be used by the cell for energy. (
  • Movement of molecules through membranes is a primary means of sending signals to and from cells. (
  • my answer was a) the cell membrane as sideways and lateral movements of protein and lipid molecules throughout the membrane, which makes it more like a fluid than a solid or rigid. (
  • The membrane contains various molecules which is why it is described as a mosaic. (
  • a) You should say what the various molecules are (phospholipids, cholesterol etc..) and their characteristics on how it makes the membrane flexible. (
  • A cell's membrane is a thin bilayer of lipid molecules among which reside other biomolecules such as proteins. (
  • The first was to develop an experiment in which neutrons scattered off of lipid molecules in the membrane without interacting with other components of the cell, such as proteins, RNA, DNA and carbohydrates. (
  • They then ensured that the lipid molecules within the membrane were made up entirely of two fatty acids containing specific proportions of deuterium and hydrogen. (
  • According to the results obtained by the researchers in Dortmund, many KRas molecules would still be lost on the available surface of the rest of the membrane systems in the cell, which is 200 times bigger than that of the cell membrane. (
  • After seven minutes, half of all KRas molecules are internalized from the cell membrane to be subjected to the cycle and sent back to the cell membrane. (
  • Interestingly, T cell activation is known to be accompanied by profound changes in the spatial organization of TCRs and downstream signaling molecules. (
  • The proteins are found around the holes and help move molecules in and out of the cell. (
  • The cell membrane is usually permeable to a number of substances, mostly small, nonpolar molecules. (
  • This protein, called clathrin, is known for its key role in the process of internalization of molecules from the extracellular space into the cell, called endocytosis. (
  • Often, larger molecules need to cross the membrane at certain points where there are transmembrane proteins , or protein channels . (
  • These are proteins in the membrane that have receptors for certain molecules and can make a hole in the membrane so they can enter. (
  • This can be used for very large molecules, or other cells through phagocytosis (cell eating). (
  • It can also be used for smaller molecules or ions through pinocytosis (cell drinking). (
  • Small molecules and electrical signals in one cell can pass through the gap junctions to adjacent cells. (
  • The membrane then forms a pit around these bound molecules, which is squeezed into a pouch, or vesicle, that detaches from the rest of the cell membrane and carries its essential cargo into the cell. (
  • Initially, most scientists believed that many dynamin molecules assembled long spirals on cell membranes, and that in the presence of GTP these spirals tightened, lopping off a vesicle. (
  • Researchers knew that dynamin is found in cells as a group of four molecules, or a tetramer. (
  • The word 'mosaic' describes the pattern produced by the scattered protein molecules when the surface of the membrane is viewed from above. (
  • The membrane is a double layer (bilayer) of phospholipid molecules. (
  • Most of the intrinsic protein molecules float like mobile icebergs in the phospholipid layers, although some are fixed like islands to structures inside or outside the cell and do not move about. (
  • Some are held in other ways - for example, by binding to molecules inside or outside the cell, or to the phospholipids. (
  • Molecules of cholesterol are also found in the membrane. (
  • Like phospholipids, cholesterol molecules have hydrophilic heads and hydrophobic tails, so they fit neatly between the phospholipid molecules with their heads at the membrane surface. (
  • The interaction of the phospholipid tails with the cholesterol molecules also helps to stabilise cells at higher temperatures when the membrane could otherwise become too fluid. (
  • The majority of the membrane is composed of two layers of phospholipid molecules lined up side by side with their fatty acid "tails" facing inward. (
  • Because of this dual chemical nature of the phospholipid bilayer, the entire membrane surface is permeable to gases (such as oxygen and carbon dioxide ), to small, uncharged polar molecules (such as water and ammonia ), and to nonpolar molecules (such as lipids). (
  • However, the membrane is impermeable to charged molecules (such as ions and proteins ) and to larger, uncharged polar molecules. (
  • Embedded within and spanning the phospholipid bilayer are various transport proteins that serve as "gates," selectively allowing charged molecules and ions and larger molecules to pass through the membrane. (
  • The plasma membrane that forms the boundary of a cell has several other molecules in addition to the basic membrane structure. (
  • Other carbohydrate molecules attached to the exterior of the plasma membrane act as "markers," identifying the cell as a particular type. (
  • Computer simulations have suggested that vinyl cyanide would behave in a similar fashion in Titan's environment, to the phospholipid molecules that make up cell membranes found in life on Earth. (
  • We still don't really know how life got started on Earth, and so studying how membranes or how possibly prebiotic molecules could form on Titan is another angle of attack of the bigger question of how any life could get started,' Ms Palmer said. (
  • [ 2 ] It contains a wide variety of biological molecules , primarily proteins and lipids , which are involved in a variety of cellular processes such as cell adhesion, ion channel conductance and cell signaling. (
  • The arrangement of hydrophilic heads and hydrophobic tails of the lipid bilayer prevent polar solutes (e.g. amino acids, nucleic acids, carbohydrates, proteins, and ions) from diffusing across the membrane, but generally allows for the passive diffusion of hydrophobic molecules. (
  • Nanowerk News ) Tiny structures made of lipid molecules and proteins have been believed to wander within the membrane of a cell, much like rafts on the water. (
  • They can act as docking stations for substances from outside, or as channels transporting molecules into the cell. (
  • On the one hand, we use super-resolution microscopy, which allows us to study single molecules, on the other hand, we can influence the cell membrane using micro- and nanostructured surfaces", says Eva Sevcsik. (
  • Tiny amounts of fluorescent markers are attached to proteins or lipids, and then molecules can be filmed as they travel within the membrane. (
  • Scientists at the University of Washington show for the first time that the complex distribution of molecules within a membrane of a living yeast cell arises through demixing. (
  • At the cathode side oxygen molecules react with the protons permeating through the polymer electrolyte membrane and the electrons arriving through the external circuit to form water molecules. (
  • [3] In addition, cell membranes are involved in a variety of cellular processes such as cell adhesion , ion conductivity and cell signalling and serve as the attachment surface for several extracellular structures, including the cell wall , the carbohydrate layer called the glycocalyx , and the intracellular network of protein fibers called the cytoskeleton . (
  • The protein components of cell membranes may function as channels or transporters across the membrane or as receptors of biochemical information. (
  • For example, myelin, a membrane that encloses some nerve cells, uses properties of lipids to act as an insulator, and so contains only one protein per 70 lipids. (
  • In general, most cell membranes are about 50 percent protein by weight. (
  • Biology) a very thin membrane, composed of lipids and protein, that surrounds the cytoplasm of a cell and controls the passage of substances into and out of the cell. (
  • This protein piece, called the fusion peptide, plays a pivotal role in merging HIV's envelope with a T cell's membrane , the first step in AIDS infection. (
  • Plants produce protein, called lectin , that binds sugars when released during cell lysis. (
  • 1. Peripheral protein on cytoplasmic side of membrane, 2. (
  • Peripheral protein on extracellular side of membrane, 3. (
  • Integral protein spanning both sides of membrane, 4. (
  • Integral protein on cytoplasmic side of membrane, 5. (
  • Peripheral protein attached to integral protein-not embedded in membrane. (
  • If you expose an intact cell to a protease enzyme, you can shave off the protein found on the outside of the cell. (
  • An antibody can be used to select a desired protein so the previous experiment can be used in real cells. (
  • Glycophorin is a protein found within red blood cells (RBC) and it spans the membrane one time. (
  • It harbours binding sites for cytoplasmic protein ligands that can be targeted to membranes through the annexin-core-mediated phospholipid interaction. (
  • Protein receptors are found ubiquitously and function to receive signals from both the environment and other cells. (
  • The arrangement of hydrophilic and hydrophobic heads of the lipid bilayer prevents hydrophilic solutes from passively diffusing across the band of hydrophobic tail groups, allowing the cell to control the movement of these substances via transmembrane protein complexes such as pores and gates. (
  • As the electrons move from one membrane protein to the next, energy is released and protons (hydrogen ions, or H + ) in the matrix are pumped across the IMM and into the intermembrane space. (
  • This mimics the membrane-protein-catalyzed assembly of phospholipids in live cells, which also uses long-chain thioesters as precursors. (
  • In addition, Corning FluoroBlok multiwell insert systems provide reliable, lot-to-lot consistent protein coatings for tumor cell inva-sion and endothelial cell migration and invasion assays. (
  • Apparently, the protein is not specifically sent to the cell membrane after it is formed, but is also located on other membrane systems within the cell for its entire life span. (
  • However, this also anchors the protein to other intracellular membranes. (
  • When it gets close to the nucleus of the cell, the activity of the protein Arl2 removes this glove. (
  • Instead, the protein redistributes to all membranes and is repeatedly sorted from the wrong membranes to the correct one. (
  • An evidence of their important role is the fact that they are the targets of more than half of today's drugs, and significant effort has therefore been devoted to the development of bioanalytical instruments capable of measuring membrane-protein controlled reactions. (
  • However, the enormous complexity of cell membranes, being built up by numerous different lipids and proteins, combined with the fact that membrane proteins must reside in this environment to function, makes functional characterization of this class of protein extremely demanding. (
  • In particular, isolation procedures needed for in-depth studies of an individual type of membrane protein is complicated by the high tendency of membrane proteins to lose function upon detergent-based solubilization procedures. (
  • This demanding challenge has spurred intense activities directed towards membrane-protein separation and enrichment protocols applicable directly on natural cell-membranes, with the aim to bypass the destructive solubilization step. (
  • Supported lipid bilayers, which are continuous two dimensional cell-membrane mimics (originally developed for biosensor applications) have due to preserved lateral mobility emerged as a promising system for this type of membrane-protein separation. (
  • The aim is in this case to tune the interaction between protein and support and thereby also influence the spatial mobility of the lipid membrane and its components. (
  • Other polar or charged particles are transported across the membrane by special embedded protein structures, and so would not be directly affected by a change in membrane permeability. (
  • Protein kinase C ε (PKC ε ) signals through RhoA to modulate cell invasion and motility. (
  • Researchers at the Bellvitge Biomedical Research Institute (IDIBELL) have just described for the first time the crucial involvement of a cell membrane protein in the development and progression of liver cancer, according to an article published in the Journal of Hepatology . (
  • The research team, led by Dr. Isabel Fabregat, who is a professor at the Faculty of Medicine and Health Sciences of the University of Barcelona and a researcher at the CIBER of Hepatic and Digestive Diseases, has shown that liver cells with invasive features have high levels of clathrin, a protein whose involvement in liver cancer was unknown until now. (
  • As a consequence, mitochondrial outer membrane integrity is highly controlled, primarily through interactions between pro- and anti-apoptotic members of the B cell lymphoma 2 (BCL-2) protein family. (
  • Describe the biosynthesis of membrane proteins and protein insertion by the translocon, and understand physico-chemical partitioning. (
  • The insertion of membrane proteins into bio-membranes is introduced by matching physic-chemical properties and investigated for spontaneous membrane protein insertion. (
  • Protein complexes involved in membrane protein insertion and in transport across the membrane will be introduced. (
  • Newswise - A team of scientists at The Scripps Research Institute and the National Institutes of Health (NIH) has discovered the structure of a protein that pinches off tiny pouches from cells' outer membranes. (
  • The structure of the protein, called dynamin, is helping to answer many longstanding questions about how vesicles form, advancing knowledge of a process critical to cell survival. (
  • Hi, can somebody recommend me an antibody against any plasma membrane protein? (
  • No matter which protein as long it is a cell surface marker! (
  • Two types of protein are recognised, according to their position in the membrane. (
  • Mapping membrane protein interactions in cell signaling systems. (
  • We proposed to apply a chemical cross-linking, mass spectrometry and modeling method called MS3D to the structure determination of the rhodopsin-transducin membrane protein complex (RTC). (
  • Herein we describe experimental progress made to adapt the MS3D approach for characterizing membrane protein systems, and computational progress in experimental design, data analysis and protein structure modeling. (
  • 2003) Evidence that the red cell skeleton protein 4.2 interacts with the Rh membrane complex member CD4. (
  • 1999) Mild spherocytosis and altered red cell ion transport in protein 4.2‐null mice. (
  • Cystic fibrosis-a fatal, hereditary disease characterized by a heavy mucus buildup in the lungs-is caused by a defective plasma membrane protein. (
  • In persons with cystic fibrosis this transport protein, known as the sodium-potassium pump, abnormally transports sodium ions across the membrane without carrying the chloride ions that usually accompany them. (
  • Research is currently underway to correct through genetic engineering the faulty gene that codes for the plasma membrane protein. (
  • JP2 protein is critical to the normal organization of an important component of heart muscle membrane network called Transverse-tubules or T-tubules. (
  • This affords the cell the ability to control the movement of these substances via transmembrane protein complexes such as pores and gates. (
  • The addition of a hydrophobic group to a protein forms a lipid anchor that attaches the protein to the lipid membrane. (
  • It wasn't until later studies with osmosis and permeability that cell membranes gained more recognition. (
  • This variation, caused by the lipid bilayer, gives the membrane its characteristic permeability . (
  • Permeability is measured as the rate at which a particular substance in solution crosses the membrane. (
  • For all cell membranes that have been studied in the laboratory, permeability increases in parallel with the permeant's ability to dissolve in organic solvents. (
  • Their functions, besides classical signal transduction at the cell surface, include regulation of membrane traffic, the cytoskeleton, nuclear events and the permeability and transport functions of membranes. (
  • The membrane permeability of animal cells and many other organisms is crucial to their survival. (
  • They function in regulation of paracellular permeability and in the maintenance of cell polarity, blocking the movement of transmembrane proteins between the apical and the basolateral cell surfaces (reviewed in 1). (
  • Stewart GW and Turner EJ (1999) The hereditary stomatocytoses and allied disorders: congenital disorders of erythrocyte membrane permeability to Na+ and K+. (
  • The phospholipid bilayer structure (fluid mosaic model) with specific membrane proteins accounts for the selective permeability of the membrane and passive and active transport mechanisms. (
  • We have established methods to evaluate key properties that are needed to commercialize polyelectrolyte membranes for fuel cell electric vehicles such as water diffusion, gas permeability, and mechanical strength. (
  • For calculating water diffusion and gas permeability through the membranes, the dissipative particle dynamics-Monte Carlo approach was applied, while mechanical strength of the hydrated membrane was simulated by coarse-grained molecular dynamics. (
  • There are two general types of membrane proteins: transporters and receptors. (
  • On resting cells (A) the B cell antigen receptors form groups and the nano ruler emits red signals (cell staining below). (
  • Reorganization of receptors on the cell membrane takes place within a range of 10 to 40 nanometers. (
  • With the help of the more precise Fab-PLA method, the scientists were able for the first time ever to investigate on a ten-nanometer scale how receptors are distributed on the membrane and how they are reorganized. (
  • When applied to the antigen receptors, the Fab-PLA method revealed red fluorescent dots on the cell membrane of inactive B cells: proof that the antigen receptors first appear on the membrane in groups, so-called receptor clusters. (
  • As soon as the B cells detected an antigen and were activated, however, the dots disappeared - the receptors had moved away from one another. (
  • The study also included an investigation of the nanoscale organization of further receptors on B cells, including the CD19 or CD20 molecule. (
  • We discovered that many receptors are organized on the membrane in specific areas at the nanoscale level," explains Kathrin Kläsener, PhD student and primary author of the study. (
  • These are probably mediated through specific cell-surface interactions with chemoattractant receptors on cells of the immune system and key enzymes of the fibrinolytic cascade, respectively. (
  • The interaction of these markers with their respective receptors forms the basis of cell-cell interaction in the immune system . (
  • The control comes from the fact that materials must pass through receptors on the epithelial cell membranes. (
  • To get past the membrane, nutrients or hormones in the bloodstream, for example, bind to specific receptors on cells membranes. (
  • Some membrane proteins serve as receptors for hormones , transferring the signal to the interior of the cell (via G proteins) without allowing the "messenger" molecule to enter, thus protecting the integrity of the cell. (
  • It contains attachments factors and receptors that the virus exploits in order to bind to the cell surface and enter the cell. (
  • The lipid bilayer hypothesis, proposed in 1925 by Gorter and Grendel, [9] created speculation to the description of the cell membrane bilayer structure based on crystallographic studies and soap bubble observations. (
  • The instrument could resolve thicknesses that depended on pH measurements and the presence of membrane proteins that ranged from 8.6 to 23.2 nm, with the lower measurements supporting the lipid bilayer hypothesis. (
  • [7] Although the fluid mosaic model has been modernized to detail contemporary discoveries, the basics have remained constant: the membrane is a lipid bilayer composed of hydrophilic exterior heads and a hydrophobic interior where proteins can interact with hydrophilic heads through polar interactions, but proteins that span the bilayer fully or partially have hydrophobic amino acids that interact with the non-polar lipid interior. (
  • [1] [2] The cell membrane consists of a lipid bilayer , including cholesterols (a lipid component) that sit between phospholipids to maintain their fluidity at various temperatures. (
  • This bilayer is the basis of the membranes of living cells. (
  • For most substances of biological interest, the concentrations inside and outside the cell are different, creating concentration gradients down which the solutes spontaneously diffuse, provided they can permeate the lipid bilayer. (
  • According to the accepted current theory, known as the fluid mosaic model , the plasma membrane is composed of a double layer ( bilayer ) of lipids, oily substances found in all cells (see Figure 1). (
  • Within the phospholipid bilayer of the plasma membrane, many diverse proteins are embedded, while other proteins simply adhere to the surfaces of the bilayer. (
  • This amphipathic quality enables the phospholipid components of the cell membrane to self-organize into a lipid bilayer. (
  • This amphipathic property causes multitudes of phospholipids suspended in water to organize naturally into a spherical, three-dimensional bilayer, which, becomes the cell membrane. (
  • The remarkable deformability of the human red blood cell (RBC) results from the coupled dynamic response of the phospholipid bilayer and the spectrin molecular network. (
  • Specifically, they used the all-atom CHARRM36 lipid force field to predict how lipids self-assemble into a bilayer membrane, using seven or eight of the main phospholipid types and two primary sterols found in soybean seedling membranes. (
  • They also plan to model transport proteins that span the lipid bilayer and other proteins critical to membrane function. (
  • The cell membrane (also called the plasma membrane , plasmalemma or "phospholipid bilayer") is a semipermeable lipid bilayer found in all cells . (
  • The cell membrane consists of a thin layer of amphipathic lipids which spontaneously arrange so that the hydrophobic "tail" regions are shielded from the surrounding polar fluid, causing the more hydrophilic "head" regions to associate with the cytosolic and extracellular faces of the resulting bilayer. (
  • Anchoring proteins restricts them to a particular cell surface - for example, the apical surface of epithelial cells that line the vertebrate gut - and limits how far they may diffuse within the bilayer. (
  • The lipid-bilayer membrane that encloses all cells and their internal organelles has due to its important role in biology and medicine been subject to intense investigations. (
  • Many functions of the cell membrane are controlled by proteins that transduce signals across the lipid bilayer, either via molecular-transport reactions or structural rearrangements. (
  • a) Schematic illustration of a continuous lipid bilayer derived from native cell membrane, (b) micrograph of the separation of two types of fluorescently labeled membrane-associated proteins, (c) microfluidic setup, (d) polymer-cushioned planar cell membrane, and (e) electrophoretic separation of transmembrane proteins. (
  • In running projects, the group is further developing these microfluidic-based (Fig. 1c) concepts with the aim to improve the spatial mobility also of membrane proteins that span across the entire lipid bilayer, which due to their close contact with the underlying support typically become immobile. (
  • A new aspect of cell membrane structure is presented, based on the dynamic clustering of sphingolipids and cholesterol to form rafts that move within the fluid bilayer. (
  • While we talk about membranes all the time, you should remember they all use a basic phospholipid bilayer structure, but you will find many variations throughout the cell. (
  • The cell membrane is made of a phospholipid bilayer . (
  • The structure is a bilayer because lipid tails are hydrophobic, meaning they do not like to be in water, which is what surrounds the membrane on both sides. (
  • The course will provide an introduction to the physic-chemical properties of lipid bilayers, before discussing processes involved in the insertion of integral membrane proteins into the lipid bilayer. (
  • suggest that the Rh complex represents a major interaction site between the membrane lipid bilayer and the red cell skeleton: ankyrin‐R is capable of interacting directly with the C ‐terminal cytoplasmic domain of Rh and RhAG polypeptides. (
  • 2003) Rh‐RhAG/ankyrin‐R, a new interaction site between the membrane bilayer and the red cell skeleton, is impaired by Rh(null)‐associated mutation. (
  • The phospholipid bilayer with its biochemical inclusions is known as the fluid mosaic model of membrane structure. (
  • For the Science study, Boxer and colleagues made a spherical lipid vesicle to model a cell membrane, placed it on a small silicon wafer to make the lipid bilayer flatten into two dimensions and organized the flat membrane with a pattern of chrome grids to provide "landmarks" on the surface. (
  • Some of these proteins, primarily those that are at least partially exposed on the external side of the membrane, have carbohydrates attached to their outer surfaces and are, therefore, referred to as glycoproteins . (
  • On the other side of the membrane, chlorine bubbles out at the anode meaning that the 'spent' brine can be resaturated with more solid salt before it is purified using an ion exchanger. (
  • They stay in the membrane because the hydrophobic regions, made from hydrophobic amino acids, are next to the hydrophobic fatty acid tails and are repelled by the watery environment either side of the membrane. (
  • Peripheral proteins are present on only one side of the membrane, and integral proteins span the entire membrane. (
  • Membrane Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the extracellular fluid on the outside. (
  • The host cell membrane is the selectively permeable membrane which separates the host cytoplasm from its surroundings. (
  • The semipermeable membrane that encloses the cytoplasm of a cell. (
  • The cell membrane surrounds the cytoplasm of a cell and, in animal cells, physically separates the intracellular components from the extracellular environment, thereby serving a function similar to that of skin . (
  • The cytoskeleton is found underlying the cell membrane in the cytoplasm and provides a scaffolding for membrane proteins to anchor to, as well as forming organelles that extend from the cell. (
  • In a process called glycolysis , which occurs in the cytoplasm just outside the mitochondrion, electrons are stripped from glucose and passed through the outer mitochondrial membrane into the intermembrane space . (
  • Swimming in the cytoplasm, KRas can thus explore the cell. (
  • Activation of PKC ε resulted in a dramatic coordinated translocation of PKC ε and RhoA from the cytoplasm to the cell membrane using time-lapse fluorescence microscopy. (
  • Stoichiometric FRET analysis revealed that the molecular interaction between PKC ε and RhoA is a biphasic event, an initial peak at the cytoplasm and a gradual prolonged increase at the cell membrane for the entire time-course (12.5 minutes). (
  • These results suggest that the PKC ε -RhoA complex is assembled in the cytoplasm and subsequently recruited to the cell membrane. (
  • Neal Devaraj, a chemistry and biochemistry professor at UC San Diego, leads a research team that develops and explores new reactions that can trigger the formation of membranes, particularly the spheres that characterize membranes that enclose vesicles and cells. (
  • In order for it to be transported by special transport vesicles from the vicinity of the cell nucleus to the cell membrane, the solubilising factor PDEδ and its antagonist Arl2 must be active. (
  • KRas is now insoluble in water again and can be trapped on membranes and transported back to the cell membrane by vesicles. (
  • Up to now, however, the creation of planar supported cell-membrane mimics from compositionally complex cell-membrane derived vesicles has remained relatively elusive. (
  • Using an improved method of fixation of the embryos for electron microscopy, we show by morphological observations that a large number of membrane-bounded, electron-transparent vesicles, of diameters ranging from 0.05 micron to 0.5 micron, are present in the periplasm and become redistributed during cellularization so as to provide the membrane mass required at each phase of the process. (
  • The vesicles then undergo concerted but not precisely synchronous fusion to form double membranes, starting at furrows in the plasma membrane of the embryo and extending about 7 microns into the periplasmic space. (
  • We presume that these vesicles fuse individually with the growing ends of the double membranes until encirclement of each nucleus is complete. (
  • In this process, the cell membrane folds creating vesicles with a cladded structure. (
  • Cells use these pouches, or vesicles, to carry nutrients and other essential substances, but many medicines also hitch a ride inside them. (
  • That study did not reveal how the dynamin collars pinch off membrane vesicles, though. (
  • This membrane allows only sodium ions and a small amount of water to pass through it as they move towards the negatively charged cathode. (
  • Our hypothesis was that stretching created small tears or holes in the myocyte membrane, which allowed calcium ions to get inside the cell. (
  • For example, a hormone binding to a receptor could open an ion channel in the receptor and allow calcium ions to flow into the cell. (
  • To function, the membrane must conduct hydrogen ions (protons) but not electrons as this would in effect "short circuit" the fuel cell. (
  • The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma ) is a biological membrane that separates the interior of all cells from the outside environment (the extracellular space). (
  • The soybean membrane is about as rigid as the yeast membrane, but twice as rigid as the sterol-deficient E. coli cytoplasmic membrane. (
  • In 1890, an update to the Cell Theory stated that cell membranes existed, but were merely secondary structures. (
  • For example, cell membranes of structures predominantly involved in energy production (e.g., the mitochondria) have a higher percentage of proteins, while membranes acting as insulators (e.g., the Schwann cell , which insulates some nerve fibers) have a higher proportion of lipids. (
  • The NMDA receptor (in green and magenta) is embedded in the neuronal cell membrane (black lollipop-like structures arranged in two rows). (
  • These structures, which can be visualized by electron microscopy or fluorescence microscopy , can be found on the inside of the membrane, the outside, or through-and-through . (
  • They include synapses , desmosomes , clathrin-coated pits , caveolaes , and different structures involved in cell adhesion. (
  • This membrane is folded and twisted throughout the mitochondrion into structures called cristae , much like all 25 feet of your small intestine is twisted and folded throughout your abdomen. (
  • The ORNL team created a strain of the bacterium containing enough deuterium to make the cell structures essentially invisible to neutrons. (
  • The utilization of lattice light-sheet microscopy has yielded important insights into structures called microvilli, which are small membrane protrusions on T cells that seem likely to have a large impact on T cell recognition and activation. (
  • Why Does Oxygen Pose a Threat to Cell Structures? (
  • The aim of this module is to provide an understanding of the structures and functions of important membrane proteins including those involved in transport, cell recognition, and energy production. (
  • For water diffusion, a map that reveals the relationship between many kinds of molecular structures and diffusion constants was obtained, in which the direction to enhance the diffusivity by improving membrane structure can be clearly seen. (
  • A compound that may form cell wall-like structures has been detected in the dense atmosphere of Saturn's moon Titan. (
  • Ms Palmer also hoped the laboratory experiments might give a real-world demonstration of vinyl cyanide forming membrane structures. (
  • But if raft-like structures travelling across the membrane do not exist, are there other mechanisms providing order among proteins and lipids? (
  • Several cell organelles (mitochondria, en. (
  • Membranes surround and protect all of our cells, and their organelles, including the mitochondria - the powerhouse of the cell. (
  • What Does Mitochondria Do in a Cell? (
  • The structure and function of specific membrane proteins involved in electron transport, proton translocation and phosphorylation in mitochondria and photosynthesis will be described and discussed in terms of our present understanding of how oxidation reactions or light energy are coupled to the synthesis of ATP. (
  • Several cell organelles (mitochondria, endoplasmic reticulum, and Golgi bodies) are also bounded by membranes. (
  • In addition, membranes in prokaryotes and in the mitochondria and chloroplasts of eukaryotes facilitate the synthesis of ATP through chemiosmosis. (
  • The length and properties of the fatty-acid components of phospholipids determine the fluidity of the cell membrane. (
  • At reduced temperatures, some organisms may vary the type and relative amounts of lipids to maintain the fluidity of their membranes. (
  • The regulation of membrane fluidity is assisted by another lipid, cholesterol , which is primarily found in eukaryotes . (
  • Explain why membranes are described as 'fluid' and how their 'fluidity' is measured. (
  • Fluidity is also affected by tail length: the longer the tail, the less fluid the membrane. (
  • At low temperatures, cholesterol increases the fluidity of the membrane, preventing it from becoming too rigid. (
  • The increased fluidity means cells can survive colder temperatures. (
  • The hydrophilic regions, made from hydrophilic amino acids, are repelled by the hydrophobic interior of the membrane and therefore face into the aqueous environment inside or outside the cell, or line hydrophilic pores which pass through the membrane. (
  • 9. Do glycoproteins span the entire membrane? (
  • Carbohydrate components are linked to lipids (to form glycolipids ) or to proteins ( glycoproteins ) on the outside of the cell membrane. (
  • Many proteins and lipids have short, branching carbohydrate chains attached to that side of the molecule which faces the outside of the membrane, thus forming glycoproteins and glycolipids, respectively. (
  • The positioning of proteins along the plasma membrane is related in part to the organization of the filaments that comprise the cytoskeleton, which help anchor them in place. (
  • The failure of tension to propagate in cells is explained by a fluid dynamical model that incorporates the flow resistance from cytoskeleton-bound transmembrane proteins. (
  • In addition, the cytoskeleton, which undergirds the cell membrane, provides anchoring points for integral membrane proteins. (
  • The cell membrane also plays a role in anchoring the cytoskeleton to provide shape to the cell, and in attaching to the extracellular matrix to help group cells together in the formation of tissues. (
  • The cytoskeleton is able to form appendage-like organelles, such as cilia, which are covered by the cell membrane and project from the surface of the cell. (
  • Zona occludens proteins ZO-1, -2, and -3 (also known as TJP1, 2, and 3) are peripheral membrane adaptor proteins that link junctional transmembrane proteins such as occludin and claudin to the actin cytoskeleton (reviewed in 2). (
  • The plasma membrane also serves as the attachment point for the intracellular cytoskeleton and, if present, the extracellular cell wall . (
  • The cytoskeleton lies directly below the cell membrane and provides stability. (
  • In the field of synthetic biology, cell membranes can be artificially reassembled . (
  • Department of Pathology and Cell Biology, The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York 10032, USA. (
  • Membrane and organelle assembly has emerged as a dominant theme in cell biology of the twenty-first century. (
  • It has long been the goal of experimental biology and medicine to induce cells to behave in predictable ways and to alter the behavior of cells in ways that are beneficial to a subject. (
  • After a ten-year effort, Prof. Dr. Michael Reth from the Institute of Biology III of the University of Freiburg and the Max Planck Institute of Immunobiology and Epigenetics has developed a method to investigate the cell surface's organization on a nanometer scale. (
  • This course covers molecular biology of prokaryotic and eukaryotic cells and their viruses. (
  • This is an introductory survey of cell and developmental biology. (
  • According to cell theory , cells are the main unit of organization in biology. (
  • Endocytosis is how cells communicate," says Sandra Schmid, chair of the Scripps Department of Cell Biology and senior author of the Nature article along with Fred Dyda at NIH. (
  • Describe the main requirement for a polymer electrolyte membrane (PEM)? (
  • A membrane electrode assembly for use with a direct organic fuel cell containing a formic acid fuel includes a solid polymer electrolyte having first and second surfaces, an anode on the first surface and a cathode on the second surface and electrically linked to the anode. (
  • Y. S. Kim and B. S. Pivovar, "Chapter four-polymer electrolyte membranes for direct methanol fuel cells," in Advances in Fuel Cells , K. D. K. T. S. Zhao and N. Trung Van, Eds. (
  • C. Cremers and D. Bayer, "Differential electrochemical mass spectrometry (DEMS) technique for direct alcohol fuel cell characterization," in Polymer Electrolyte Membrane and Direct Methanol Fuel Cell Technology , C. Hartnig and C. Roth, Eds. (
  • Y. S. Kim and P. Zelenay, "Direct methanol fuel cell durability," in Polymer Electrolyte Fuel Cell Durability , F. N. Büchi, M. Inaba, and T. J. Schmidt, Eds. (
  • PEMFC (Polymer Electrolyte Membrane Fuel Cell) is expected to be one of the major power source for the future passenger vehicle as it features high power density and short starting time in addition to its own environment-friendly characteristics. (
  • Development of Carbon Composite Bipolar Plate for Polymer Electrolyte Membrane Fuel Cell in Passenger Vehicle," SAE Technical Paper 2008-01-0313, 2008, . (
  • Proton-exchange membrane fuel cells (PEMFC), also known as polymer electrolyte membrane (PEM) fuel cells, are a type of fuel cell being developed mainly for transport applications, as well as for stationary fuel-cell applications and portable fuel-cell applications. (
  • Their distinguishing features include lower temperature/pressure ranges (50 to 100 °C) and a special proton-conducting polymer electrolyte membrane. (
  • PEMFCs are built out of membrane electrode assemblies (MEA) which include the electrodes, electrolyte, catalyst, and gas diffusion layers. (
  • An ink of catalyst, carbon, and electrode are sprayed or painted onto the solid electrolyte and carbon paper is hot pressed on either side to protect the inside of the cell and also act as electrodes. (
  • The pivotal part of the cell is the triple phase boundary (TPB) where the electrolyte, catalyst, and reactants mix and thus where the cell reactions actually occur. (
  • This oxidation half-cell reaction or hydrogen oxidation reaction (HOR) is represented by: At the anode: The newly formed protons permeate through the polymer electrolyte membrane to the cathode side. (
  • It is an animation that is put together very well and provides a nice visualization of molecular components found in the cell membrane. (
  • The presence of cholesterol and glycolipids, which are found in most cell membranes, can also affect molecular dynamics and inhibit phase transitions. (
  • C) Dependence of diffusion coefficients for membrane tension (red) and molecular tracers (blue) on the area fraction Φ i of immobile proteins. (
  • The characteristics of this metabolically driven dynamics are observed only in the convex regions of the RBC membrane, with a periodic spacing on the order of the spectrin molecular network length scale. (
  • Researchers at the University of Maryland, in College Park, have developed a detailed computational model of the soybean plasma membrane that provides new structural insight at the molecular level. (
  • Swairjo, M. A. & Seaton, B. A. Annexin structure and membrane interactions: a molecular perspective. (
  • Specific proteins embedded in the cell membrane can act as molecular signals that allow cells to communicate with each other. (
  • Scientists at the Max Planck Institute of Molecular Physiology in Dortmund have now discovered why KRas is almost exclusively found at the cell membrane when observed under the microscope. (
  • Instead, KRas constantly and unspecifically re-distributes to the various membrane systems of the cell and must then be concentrated on the inner leaflet of the cell membrane via a continuous cycle," explains Malte Schmick from the Max Planck Institute of Molecular Physiology. (
  • Continuous Lipid Bilayers Derived from Cell Membranes for Spatial Molecular Manipulation. (
  • Through the process of building the molecular structure of an animated cell membrane, site visitors will learn "the makeup and the basis for cell membrane function. (
  • Using our surface-based approaches we study the molecular and physical mechanisms modulating HSV binding and release from the cell surface (Figure 2). (
  • In order to achieve high mechanical strength, the molecular structure should be such that the hydrated membrane contains narrow water channels, but these might decrease the proton conductivity. (
  • We place molecular building blocks on the micro structured surface, which bind to specific proteins in the cell membrane. (
  • Behind this movement of solutes across the cell membrane is the principle of diffusion . (
  • Those membrane proteins serving as pumps accomplish this by coupling the energy required for transport to the energy produced by cell metabolism or by the diffusion of other solutes. (
  • The principle of permeation can be illustrated by differences in the diffusion of sugar and water through a membrane. (
  • Permeation occurs when a substance moves through the membrane from a region of high concentration to a region of low concentration, a process called diffusion. (
  • Perturbations to tension propagate diffusively, with a diffusion coefficient D σ ∼0.024 μm 2 /s in HeLa cells. (
  • What Do Facilitated Diffusion Carrier Proteins and Cell Membranes Both Pump? (
  • Facilitated diffusion uses carrier proteins to pump substances across the cell membrane that would not normally be able to cross the membrane on their own. (
  • Amino acids, glucose and other large membrane insoluble compounds move through the cell membrane through a process known as facilitated diffusion. (
  • In complement to the use of cell-membrane mimics, our group is developing and implementing experimental methods based on live cell microscopy to probe virus attachment to, diffusion on and uptake through the cell membrane on a single particle level. (
  • I was wondering if ATP can get into a cell either by diffusion or actively transport. (
  • and (2) subsequently contacting the cell surface with a composition comprising a second member of the binding pair selected from the group consisting of avidin or streptavidin linked to a death ligand selected from the group consisting of Fas ligand (FasL), and the extracellular portion of Fas ligand to form a decorated cell surface, wherein the decorated cell surface is capable of inducing apoptosis. (
  • Fungal pathogens almost invariably trigger cell wall-associated defense responses, such as extracellular hydrogen peroxide generation and callose deposition, when they attempt to penetrate either resistant or susceptible plant cells. (
  • The cell membrane controls the movement of substances in and out of cells and organelles. (
  • Yet the membrane is also a formidable barrier, allowing some dissolved substances, or solutes, to pass while blocking others. (
  • It regulates the substances that can enter and leave the cell. (
  • The membrane acts as a boundary, holding the cell constituents together and keeping other substances from entering. (
  • The cell membrane is one of the most important components of a cell because it separates the interior from the environment and controls the movement of substances in and out of the cell. (
  • As a semi-permeable barrier, the cell membrane maintains an essential balance between individual distinctness and communal interaction: it functions to retain key components of the cell and to keep out toxic or unwanted substances, while selectively controlling the flow of nutrients and biochemical signals into the cell. (
  • This allows him to monitor how the antigen receptor, which B cells of the immune system use to recognize foreign substances, changes after activation. (
  • The movement of substances across the membrane can be either passive , occurring without the input of cellular energy, or active , requiring the cell to expend energy in moving it. (
  • But cells also need some substances to get inside. (
  • This is accomplished by the semipermeable nature of the membrane that regulates the passage of all substances going through it. (
  • The cell membrane surrounds all cells and it is selectively-permeable , controlling the movement of substances in and out of cells. (
  • The paucimolecular model immediately became popular and it dominated cell membrane studies for the following 30 years, until it became rivaled by the fluid mosaic model of Singer and Nicolson (1972). (
  • Despite the numerous models of the cell membrane proposed prior to the fluid mosaic model , it remains the primary archetype for the cell membrane long after its inception in the 1970s. (
  • The fluid-mosaic model posits a liquid-like plasma membrane, which can flow in response to tension gradients. (
  • A humidity sensing device for determining the amount of humidity in at least one primary fluid stream that is passed to a fuel cell stack is provided. (
  • 14. The membrane electrode assembly of claim 10 wherein each of said layers of sheet material has grooves formed in the surface thereof facing away from said membrane, said grooves having an extrudable sealant material deposited therein, said grooves generally circumscribing said fluid passage openings. (
  • The bag is the cell membrane, very fluid, but it keeps all of the contents inside. (
  • 4 This model has continually evolved over the past 80 years, thanks to a succession of seminal contributions that included outlining of the fluid mosaic model of the structure of cell membranes by Singer and Nicolson, 5 isolation of spectrin by Marchesi and Steers, 6 and the definition of the topology of red cell membrane proteins by Steck and colleagues. (
  • The more unsaturated they are, the more fluid the membrane. (
  • The fluid mosaic model can be seen when the membrane proteins of two cells (e.g., a human cell and a mouse cell) are tagged with different-coloured fluorescent labels. (
  • The membrane, the outermost layer of the cell, is fluid. (
  • The membrane also contains membrane proteins , including integral proteins that go across the membrane serving as membrane transporters , and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes shaping the cell. (
  • these intrinsic or integral proteins are difficult to remove without destroying the membrane itself. (
  • Intrinsic proteins or integral membrane proteins may be said to reside within the membrane or to span it. (
  • The cell membrane contains many integral membrane proteins , which pepper the entire surface. (
  • Proteins that are found embedded within the Membrane are called intrinsic proteins (or integral proteins). (
  • Proteins in the cell membranes may be integral or peripheral . (
  • In each layer of a plasma membrane, the hydrophobic lipid tails are oriented inwards and the hydrophilic phosphate groups are aligned so they face outwards, either toward the aqueous cytosol of the cell or the outside environment. (
  • The arrangement of proteins also involves the hydrophobic and hydrophilic regions found on the surfaces of the proteins: hydrophobic regions associate with the hydrophobic interior of the plasma membrane and hydrophilic regions extend past the surface of the membrane into either the inside of the cell or the outer environment. (
  • Both the bacteria and higher-level organisms have a double layer cell membrane composed of phospholipids, where the hydrophobic tails of each layer point toward the middle of the membrane and hydrophilic heads face the outside and inside of the cell. (
  • The outer edges of the membrane are hydrophilic (soluble in water ), while the interior area is hydrophobic (insoluble in water). (
  • Paul Andersen explains how cells are selectively permeable with the help of their cell membrane. (
  • The barrier is selectively permeable and able to regulate what enters and exits the cell, thus facilitating the transport of materials needed for survival. (
  • The cell membrane is semi-permeable , which means that only certain things can move in and out of the cell. (
  • Net movement of water through a selectively permeable membrane from an area of high concentration of water (lower concentration of solutes) to one of lower concentration of water  Water can pass through plasma membrane in 2 ways: 3. (
  • 10. What do animal membranes have that plant membranes do not? (
  • The researchers focused on the soybean plasma membrane because it is one of the most intensely studied plant membranes, which provided substantial experimental data to be used in validating the computational model. (
  • While these simulations represent the state-of-the-art in computational modeling of complex lipid membranes, Klauda acknowledges that he would have liked to include a greater diversity of lipid types in the simulation, as plant membranes can be composed of hundreds of different lipids, but the model could only accommodate the 10 most dominant ones. (
  • Led by Yushan Yan, Distinguished Professor of Engineering, the research at UD will focus on creating a series of polymer-based hydroxide exchange membranes (HEMs). (
  • Our goal is to develop a process to easily synthesize the polymer at scale, creating large area membranes for testing that are thinner than human hair. (
  • One approach is to utilize polymer cushions (Fig. 1d) in order to separate the lipid membrane from the underlying support and thereby maintain the mobility of transmembrane proteins. (
  • A first and second layer of porous electrically conductive sheet material, such as carbon filter paper, has a solid polymer ion exchange membrane interposed therebetween. (
  • 2. The membrane electrode assembly of claim 1 wherein said membrane is a solid polymer ion exchange membrane. (
  • the membrane, which provides a layer between the cathode and the anode in the fuel cell, is a honeycombed plastic polymer that also includes platinum and other materials. (
  • Also called cytomembrane , plasmalemma , plasma membrane . (
  • The cell membrane (also called the plasma membrane or plasmalemma ) is one biological membrane separating the interior of a cell from the outside environment . (
  • i.e., containing both a lipid-soluble and a water-soluble region) is basic to the role of lipids as building blocks of cellular membranes. (
  • These include effects on actin assemblies at cellular membranes, the organization of endosomal subcompartments, Ca 2+ -regulated exocytosis and midbody formation during cytokinesis. (
  • Investigators from the Lawrence Livermore National Laboratory (LLNL), Stanford and UC Davis, using high-resolution secondary ion mass spectrometer called NanoSIMS, are taking a close look at cellular membranes. (
  • Cell membranes assist in the organization of individual cells to form tissues. (
  • Membrane-bound annexins can form lateral self-assemblies that affect the mobility and organization of membrane lipids. (
  • Such activities probably regulate membrane-related processes like membrane-domain organization and membrane transport in endocytosis and exocytosis. (
  • Figure 4: Annexins in membrane organization and trafficking. (
  • Organization of lipids in distinct domains within the cell membrane is thought to enable functions such as signaling between cells. (
  • Two electric connection points of each chlorine production cell, the anode and the cathode, are separated by an ion-exchange membrane. (
  • The electrons travel along an external load circuit to the cathode side of the MEA, thus creating the current output of the fuel cell. (
  • This reduction half-cell reaction or oxygen reduction reaction (ORR) is represented by: At the cathode: Overall reaction: The reversible reaction is expressed in the equation and shows the reincorporation of the hydrogen protons and electrons together with the oxygen molecule and the formation of one water molecule. (
  • Finally, the membrane must be resistant to the reducing environment at the cathode as well as the harsh oxidative environment at the anode. (
  • Water management is a very difficult subject in PEM systems, primarily because water in the membrane is attracted toward the cathode of the cell through polarization. (
  • They interact extensively with the fatty acid chains of membrane lipids and can be released only by agents that compete for these non-polar interactions. (
  • Omega-3 fatty acids, often called essential fats, are necessary for the formation of healthy cell membranes. (
  • some organisms which cannot regulate their own temperature, such as bacteria and yeasts, respond by increasing the proportion of unsaturated fatty acids in their membranes. (
  • This suggests that if the primary site of ozone action is unsaturated lipids in membranes then the amounts of affected unsaturated fatty acids are too small to be detected by gas chromatography. (
  • Associations of different proteins in a section of compositionally distinct fatty membrane have been called "lipid rafts. (
  • Known as the host cell inner membrane in prokaryotes with 2 membranes. (
  • Flippases and Scramblases concentrate phosphatidyl serine , which carries a negative charge, on the inner membrane. (
  • A mitochondrion has an outer and inner membrane. (
  • The inner membrane holds digestive enzymes that break down food. (
  • The electroinsertion process involves exposing red blood cells to a pulsed electrical field, thereby enabling the CD4 to be incorporated into the red blood cell's membrane to form RBC-CD4 which acts as a sponge absorbing free-floating HIV and forming aggregates with HIV-infected cells. (
  • They are also involved in biological communication: the binding of a specific substance to the exterior of the membrane can initiate, modify, or turn off a cell function. (
  • In: Conti F., Blumberg W.E., de Gier J., Pocchiari F. (eds) Physical Methods on Biological Membranes and Their Model Systems. (
  • Lipid domains are too small to be seen by optical microscopes that use light to probe samples such as biological cells. (
  • While a biological cell itself perceives little difference between normal hydrogen and deuterium, the two isotopes appear very different when looked at using neutron scattering. (
  • Corning BioCoat angiogenesis systems are composed of 3.0 μm inserts with biological coatings optimized for use in endothelial cell migration and invasion assays. (
  • The module will discuss the structure and function of biological membranes. (
  • Describe the basic features of the structure of biological membranes. (
  • The module will cover the structure and function of biological membranes. (
  • I want to continue talking about these hydrolyzable lipids but the other ones that I think are important instead of kind of having a predominant energy storage function, they have a structural function in our cells and kind of in the biological role, so a structural function. (
  • However, some microscopists correctly identified at this time that while invisible, it could be inferred that cell membranes existed in animal cells due to intracellular movement of components internally but not externally and that membranes weren't the equivalent of a cell wall to plant cell. (
  • Thus, membrane tension is not a mediator of long-range intracellular signaling, but local variations in tension mediate distinct processes in sub-cellular domains. (
  • Eukaryotic cells contain various Ca 2+ -effector proteins that mediate cellular responses to changes in intracellular Ca 2+ levels. (
  • From this, the cell must selectively absorb nutrients that are essential to its growth and function. (
  • In prokaryotes and plants, the plasma membrane is an inner layer of protection since a rigid cell wall forms the outside boundary for their cells. (
  • Eukaryotic animal cells are generally thought to have descended from prokaryotes that lost their cell walls. (
  • A cell membrane (also known as a plasma membrane) is a thin semifluid structure that separates the contents of a cell or organelle from its surroundings. (
  • Each organelle is surrounded by a separate membrane whose function is similar to that of plasma membranes, but with a slightly different composition that enables the organelle to perform specific tasks. (
  • Once the small bubble was blown inside of the bigger bubble it was a model of the phospholipids in the organelle membranes. (
  • Organelle membranes do not have the same chemical makeup as the cell membrane. (
  • The membrane allows a cell or organelle to maintain a constant internal environment, usually one that is quite different from the medium surrounding it. (
  • For fuel cells, membranes are involved in fuel processing and as proton-exchange and hydroxyl ion-exchange materials in membrane electrode assemblies. (
  • Proton-exchange and hydroxyl ion-exchange membranes and membrane electrode assemblies, including cost-effective Nafion replacements particularly for 120 - 180oC and new membranes for alkaline fuel cells, are critical to the widespread use of fuel cells. (
  • Original and review papers on membranes for fuel cell applications are sought, including (1) fuel processing, (2) proton-exchange membranes, (3) hydroxyl ion-exchange membranes, and (4) membrane electrode assemblies. (
  • 1. A membrane electrode assembly for an electrochemical fuel cell comprising first and second layers of porous electrically conductive sheet material and a membrane interposed therebetween, said layers of sheet material covering and supporting substantially the entire surface of said membrane. (
  • 3. The membrane electrode assembly of claim 2 wherein said sheet material comprises carbon fiber paper. (
  • 4. The membrane electrode assembly of claim 3 wherein said membrane has a thickness between about 0.001 inches and about 0.005 inches. (
  • 6. The membrane electrode assembly of claim 5 wherein said catalyst comprises platinum. (
  • 7. The membrane electrode assembly of claim 5 wherein said catalyst is included on at least a portion of the surface of each of said layers of sheet material facing said membrane. (
  • 8. The membrane electrode assembly of claim 7 wherein said catalyst is included on the central portion of each of said layers of sheet material, said central portion substantially coinciding with the flow field carrying reactant gas to said sheet material layer. (
  • 9. The membrane electrode assembly of claim 5 wherein said layers of sheet material and said membrane are bonded together to form a consolidated membrane electrode assembly. (
  • 10. The membrane electrode assembly of claim 5, said layers of sheet material and said membrane having openings formed therein to accommodate the passage of fluids through said assembly. (
  • 11. The membrane electrode assembly of claim 10 wherein said fluids include fuel gas, oxidant gas and coolant. (
  • 12. The membrane electrode assembly of claim 11 wherein said coolant is water. (
  • To understand the dyanmics of membrane constituents together with the mechanisms of transport pathways. (
  • Structural and functional characterization of the many constituents of the red cell membrane, in conjunction with biophysical and physiologic studies, has led to detailed description of the way in which the remarkable mechanical properties and other important characteristics of the red cells arise, and of the manner in which they fail in disease states. (
  • A) Illustration of the cell plasma membrane with some transmembrane proteins bound to the underlying cortex. (
  • Springs represent the elastic response of the membrane to stretch, and dampers represent the viscous drag from immobile transmembrane proteins. (
  • Once local enrichment of transmembrane proteins is successfully accomplished, it is our aim to employ surface analytical tools, such as SPR, TIRF microscopy, electrical impedance spectroscopy and QCM-D, for functional studies of membrane proteins in a near-native cell-membrane environment. (
  • Some are only attached to the inner or outer layer of the membrane while the transmembrane proteins pass through the entire structure. (
  • Our current concept of the red cell membrane envisions it as a composite structure in which a membrane envelope composed of cholesterol and phospholipids is secured to an elastic network of skeletal proteins via transmembrane proteins. (
  • Intrinsic proteins may be found in the inner layer, the outer layer or, most commonly, spanning the whole membrane, in which case they are known as transmembrane proteins. (
  • In transmembrane proteins, the hydrophobic regions which cross the membrane are often made up of one or more α-helical chains. (
  • AUGUSTA, Ga. -A class of drugs widely used to treat osteoporosis appears to impede a cell's ability to repair a protective outer membrane that helps determine what enters and exits, researchers report. (
  • Working in the lab of Dr. Paul McNeil, an MCG cell biologist specializing in cell membrane repair, Lewis found that kidney epithelial cells from monkeys and muscle cells from mice both lost their ability to quickly repair their outer membrane after exposure to zoledronate, a commonly used bisphosphonate, Lewis said. (
  • The outer membrane contains the mitochondrion parts. (
  • Mitochondrial outer membrane permeabilization (MOMP) is often required for activation of the caspase proteases that cause apoptotic cell death. (
  • For example, the carbohydrate unit of some glycolipids changes when a cell becomes cancerous , which may allow white blood cells to target cancer cells for destruction. (
  • Which has empirically proven that glycolipids and proteins contain sugars only on the external side of the cell membrane. (
  • H-K) Repetition of the experiment in (D-F) in H) NIH 3T3 fibroblasts, I) MDCK epithelial cells, J) mouse brain endothelial cells, and K) rat hippocampal neurons. (
  • Kidney epithelial cells and muscle cells used in this study are routinely used in cell membrane repair research, and cell repair mechanisms tend to be consistent across cell types, even across different species, McNeil noted. (
  • The membrane integrates safely into patient's eyes, with excellent and fast results for all types of dry eyes, neurotrophic keratitis, persistent corneal epithelial defects, Steven Johnson syndrome, recurrent corneal erosion, keratoplasty, eyelid fornix reconstruction along with additional corneal and conjunctival pathology. (
  • The apical surfaces of the aforementioned epithelial cells are dense with finger-like projections, called microvilli , which increase cell surface area and thereby increase the absorption rate of nutrients. (
  • During cycle 14 interphase, a wave of membrane formation encircles each nucleus inside its own plasma membrane, thereby generating an intact epithelial layer. (
  • The respiratory membrane, also called the respiratory surface, is made of the alveolar epithelial cell and the pulmonary capillary endothelial cell, and th. (
  • Tight junctions block the flow of fluids between epithelial cells. (
  • All living cells, prokaryotic and eukaryotic, have a plasma membrane that encloses their contents and serves as a semi-porous barrier to the outside environment. (
  • These are found on the inner or outer surface of the membrane. (
  • in contrast, water and alcohols permeate most membranes in less than a second. (
  • The relative number of proteins and lipids depends on the specialized function of the cell. (
  • and delineating the nature of interactions among various membrane proteins and between proteins and lipids. (
  • After the gold and ConA are allowed to attach to the manose, the cell can then be prepared for electron microscopy and the gold can be seen (because gold scatters electrons). (
  • Firstly, the role of multi-domain cell surface proteins involved in cell recognition and secondly, the components of the electron-transport chain and its relation to energy transduction including an introduction to Mitchell's chemi-osmotic hypothesis. (
  • Color enhanced scanning transmission electron micrograph of cell membranes of adjoining cells separated by an intercellular cleft. (
  • The objective of this study was to determine the effects of ozone on membrane lipids and on the electron-density patterns of cell membranes in electron micrographs. (
  • In support of this, characteristic electron-microscopic images of membranes are observed in cells of fumigated leaves. (
  • misc{etde_5353682, title = {Effect of ozone on leaf cell membranes} author = {Swanson, E S, Thomson, W W, and Mudd, J B} abstractNote = {The objective of this study was to determine the effects of ozone on membrane lipids and on the electron-density patterns of cell membranes in electron micrographs. (
  • Extrinsic or peripheral proteins simply adhere to the membrane and are bound by polar interactions. (
  • Higher-level cells known as eukaryotes contain specialized components, called organelles, that play dedicated roles in its growth and development. (
  • transport channels have been shown to exist in the organelles of yeast cells and are essential to cell viability. (
  • Eukaryotic cells are generally ten times larger than prokaryotic cells and have membranes enclosing interior components, the organelles. (
  • The virtual cell permits the students to understand structure and function of yeast organelles. (
  • As you learn more about cell organelles, you will find that they all have a membrane. (
  • Some organelles have two membranes. (
  • She discovered the elasticity and composition of several large organelles, and the cell membrane itself. (
  • Plasma Membrane The plasma membrane is a very thin, continuous sheet of phospholipids and proteins that surrounds all living cells and separates them from their external environment. (
  • The membrane that surrounds a lysosome is different from the membrane around the endoplasmic reticulum . (
  • The phospholipid heads face the aqueous (water-containing) medium that surrounds the membranes. (
  • Water and gases across the red blood cell membrane. (
  • Cooke BM, Mohandas N and Coppel RL (2004) Malaria and the red blood cell membrane. (
  • There is a specific type of active transport called endocytosis , where the cell membrane forms around the molecule and creates a "pocket" for the molecule. (
  • Nerve cells use this same vesicle-making mechanism, called endocytosis, to maintain signaling from one cell to another. (
  • Despite the importance of endocytosis, scientists have been puzzled by how cells perform this process. (
  • The bipolar plate is a multi-functional component that mechanically separates unit cells, offering flow paths for hydrogen, oxygen, and coolant through complicated channels engraved on it. (
  • The chemical structure of the cell membrane makes it remarkably flexible, the ideal boundary for rapidly growing and dividing cells. (
  • In animals , the cell membrane establishes this separation alone, whereas in yeast , bacteria and plants , an additional cell wall forms the outermost boundary, providing primarily mechanical support. (
  • The outer boundary of a cell. (
  • however, the cell wall plays mostly a mechanical support role rather than a role as a selective boundary. (
  • In fungi , bacteria , and plants an additional cell wall forms the outermost boundary, however, the cell wall plays mostly a mechanical support role rather than a role as a selective boundary. (
  • however, the cell wall plays mostly a mechanical support role rather than a role as a selective boundary [ citation needed ] . (
  • Membranes serve diverse functions in eukaryotic and prokaryotic cells. (
  • The basic function of the cell membrane is to protect the cell from its surroundings. (
  • This site includes an animated presentation of the cell membrane that walks users through the structure and function of individual components. (
  • Plasma membrane proteins function in several different ways. (
  • The confluence of morphologic, genetic and biochemical approaches laid the foundations for study in this area, and they continue to strengthen our understanding of this essential aspect of cell structure and function. (
  • A major cellular manifestation of motor neuron disease is the inability of nerve cells to stimulate the opening of channels through the membranes of muscle cells, which would result in normal muscle function. (
  • The regulation of transport, though a crucial function of the cell membrane, is not its only role. (
  • Methods and compositions are provided for the persistent modification of cell membranes with exogenous proteins so as to alter the function of the cell to achieve effects similar to those of gene therapy, without the introduction of exogenous DNA. (
  • This invention relates to the persistent modification of cell membranes so as to alter the function of the cells. (
  • A useful alteration of cell function is the induction of apoptosis. (
  • For example, if undesired cells could be induced to alter their behavior to undergo apoptosis while normal cells retain normal function, subjects with a disease caused by proliferation of undesired cells would obtain relief from the disease. (
  • By forming networks on the membrane surface, annexins can function as organizers of membrane domains and membrane-recruitment platforms for proteins with which they interact. (
  • Liemann, S. & Lewit-Bentley, A. Annexins: a novel family of calcium- and membrane-binding proteins in search of a function. (
  • Test your knowledge about cell differentiation, cell function and tissue culture. (
  • In order for KRas to be able to function correctly, it must remain on the inner leaflet of the cell membrane for a sufficient period of time. (
  • It is proposed that these rafts function as platforms for the attachment of proteins when membranes are moved around inside the cell and during signal transduction. (
  • What Is the Structure and Function of the Respiratory Membrane? (
  • In vitro experiments of this recent work have allowed the IDIBELL researchers to demonstrate that clathrin cell levels determine, via EGFR, the function of TGF-β. (
  • MOMP typically leads to cell death irrespective of caspase activity by causing a progressive decline in mitochondrial function, although cells can survive this under certain circumstances, which may have pathophysiological consequences. (
  • Current studies in this very active and exciting field are continuing to produce new and unexpected revelations on the function of the red cell membrane and thus of the cell in health and disease, and shed new light on membrane function in other diverse cell types. (
  • Finally, the need for signaling is a function of gap junctions that form pores connecting adjacent cells. (
  • 1. FUNCTION : controls the exchange of materials such as nutrients and waste products between the cell and its environment. (
  • In this animated activity, learners examine nanotechnology applications that are based on cell membrane structure and function. (
  • The structure and function of the red cell membrane and associated ion transporters play an important role in the pathology of red cell genetic defects. (
  • This abnormal redistribution of JP2 leads to loss of normal heart cell function and ultimately heart failure. (
  • If junctophilin-2 is not in its proper destination, then the cell cannot function properly, which leads to the development and progression of heart failure. (
  • This observation is shown quantitatively by examining the retention of Leukemia Inhibitory Factor (LIF, a factor required for the maintenance of pluripotency of murine embryonic stem cells, or mESCs) as a function of multiple filtrations through a PES membrane Stericup ® Quick Release filter device. (
  • You get one of these pieces of grease stuck on you, and now you become associated with the membrane and you find yourself in one of these rafts, whatever they are, and now you meet your friends, and the result is specialized function. (
  • These plasma membranes contain proteins that are involved in controlling what goes in and out of the cell, so to look at those proteins that reside in the membrane, we need to understand what the membrane is. (
  • In an attempt to accept or reject the hypothesis, researchers measured membrane thickness. (
  • The researchers achieved the breakthrough by switching the operating environment from acidic to basic, which is enabled by the membranes like the one funded by this IONICS project. (
  • On the other hand, zoledronate-exposed cells quickly filled with a fluorescent dye the researchers placed in the petry dish. (
  • The researchers also demonstrated how the dissociation occurs: They deleted in B cells the gene encoding the signaling molecule Syk, a kinase that closely cooperates with the antigen receptor. (
  • In order to elucidate the further details of the activation of B cells, the researchers introduced Syk and the antigen receptor components into fruit fly cells. (
  • Researchers have been uncertain about whether membrane lipids sometimes organize into groups called domains, also known as "rafts," or if they are randomly distributed in the membrane. (
  • Researchers are in desperate need of single-cell analysis techniques and those that allow the isolation of high-value T-cells for research and development. (
  • To test for the presence of tears in myocyte membranes, U-M researchers used a special fluorescent dye, which cannot penetrate an intact cell membrane. (
  • A proton exchange membrane fuel cell transforms the chemical energy liberated during the electrochemical reaction of hydrogen and oxygen to electrical energy, as opposed to the direct combustion of hydrogen and oxygen gases to produce thermal energy. (
  • The space inside the IMM is called the matrix , while the space between the two mitochondrial membranes is cleverly named the intermembrane space . (
  • The ability of a mitochondrion to convert glucose and ADP , adenosine diphosphate, into ATP is intricately connected to the structure of the mitochondrial membranes. (
  • This awesome process is called cellular respiration , and it is all made possible by the mitochondrial membranes! (
  • [7] Microscopists focused on the cell wall for well over 150 years until advances in microscopy were made. (
  • By the second half of the 19th century, microscopy was still not advanced enough to make a distinction between cell membranes and cell walls. (
  • Using complex computer simulations, the scientists evaluated data from fluorescence microscopy experiments and tracked the movement of KRas on its journey though the cell. (
  • New developments in light microscopy have since allowed attention to turn to the very earliest stages of T cell activation, and to resting cells, at high resolution. (
  • This includes single-molecule localization microscopy, which has been applied to the question of whether TCRs are pre-clustered on resting T cells, and lattice light-sheet microscopy that has enabled imaging of whole cells interacting with antigen-presenting cells. (
  • Microscopy has yielded especially valuable insights into the dynamics of T cell behavior and signaling in vitro and in vivo . (
  • As a complement to traditional cell studies used in the field of virology, our group develops surface-based assays in combination with advanced microscopy techniques. (
  • Like the exterior plasma membrane, these membranes also regulate the flow of materials, allowing the cell to segregate its chemical functions into discrete internal compartments. (
  • Some annexins can also occur extracellularly and can have functions outside cells. (
  • A unique class of these proteins - annexins - can bind to certain membrane phospholipids in a Ca 2+ -dependent manner, providing a link between Ca 2+ signalling and membrane functions. (
  • But in advanced stages of liver cancer, where this signaling pathway is highly activated, tumor cells have acquired capabilities to escape its suppressor functions and respond to TGF- β by inducing cell migration and invasion, and thus contributing to tumor spreading. (
  • The detailed chemical composition of a membrane varies, depending on its location and the functions it performs. (
  • These rafts may serve many functions such as reacting to stress, conferring immunity through antibody response, adhering to other cells and countering bacteria and toxins. (
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