Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Membranes: Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.Membrane Lipids: 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.Intracellular Membranes: 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.Membrane Potentials: 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).Erythrocyte Membrane: The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.Membranes, Artificial: 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.Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Membrane Fluidity: 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.Basement Membrane: 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.Lipid Bilayers: Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.Microscopy, Electron: 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.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Membrane Transport Proteins: 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.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Protein Transport: 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.Protein Binding: 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.Liposomes: 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.Calcium: 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.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Models, Biological: 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.Mitochondrial Membranes: 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, Cultured: 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.Synaptic Membranes: 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.Molecular Sequence Data: 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.Hydrogen-Ion Concentration: 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)Protein Structure, Tertiary: 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, Fluorescence: 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.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Cell Fractionation: Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.Potassium: 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.Cell Membrane Structures: Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.Detergents: 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.Phosphatidylcholines: 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, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Amino Acid Sequence: 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.Escherichia coli: 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.Mutation: 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.Bacterial Proteins: Proteins found in any species of bacterium.Freeze Fracturing: 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.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.Microscopy, Confocal: 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.Molecular Weight: The sum of the weight of all the atoms in a molecule.Temperature: 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.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Endoplasmic Reticulum: 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 Fusion Proteins: 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.Cytoplasm: 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)Golgi Apparatus: 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)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Rabbits: 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.Kinetics: The rate dynamics in chemical or physical systems.Endocytosis: Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Extraembryonic Membranes: 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.Fluorescent Dyes: 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.Ion Channels: 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.Subcellular Fractions: 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)Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Diffusion: 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.Signal Transduction: 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, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Fluorescent Antibody Technique: 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.Microvilli: Minute projections of cell membranes which greatly increase the surface area of the cell.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Cholesterol: The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.Solubility: 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)Cattle: 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.Protein Conformation: 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).Adenosine Triphosphate: 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.Peptides: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Mitochondria: 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)Blotting, Western: 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.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Octoxynol: 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, Immunoelectron: 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.Transfection: 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.Cytosol: Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.Permeability: Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.Phosphatidylserines: 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.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Phosphatidylethanolamines: 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.Protein Structure, Secondary: 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.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Receptors, Cell Surface: 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.CHO Cells: 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.Exocytosis: Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Cytoskeleton: The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.Cloning, Molecular: 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.Membrane Potential, Mitochondrial: 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.Anion Exchange Protein 1, Erythrocyte: 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.Spectrin: 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.Green Fluorescent Proteins: 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.Electrophysiology: 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.Purple Membrane: 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)Unilamellar Liposomes: Single membrane vesicles, generally made of PHOSPHOLIPIDS.Spectrometry, Fluorescence: Measurement of the intensity and quality of fluorescence.Microscopy, Electron, Scanning: 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.HeLa Cells: 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.Endosomes: Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.Vacuoles: Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.Immunoblotting: 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.Actins: 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.Freeze Etching: 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.COS Cells: 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).)Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.beta-Cyclodextrins: Cyclic GLUCANS consisting of seven (7) glucopyranose units linked by 1,4-glycosidic bonds.Epithelial Cells: 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.Lipids: 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)Dogs: 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)Epithelium: One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.Nictitating Membrane: 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.Bruch Membrane: 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.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Sodium-Potassium-Exchanging ATPase: 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.Water: 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)Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.GTP-Binding Proteins: 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.-.Enzyme Activation: 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.Binding, Competitive: 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.Patch-Clamp Techniques: 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, Monoclonal: Antibodies produced by a single clone of cells.Structure-Activity Relationship: 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.Sphingomyelins: 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.Guinea Pigs: 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.Cercopithecus aethiops: 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.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Osmosis: Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Complement Membrane Attack Complex: 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.Hydrophobic and Hydrophilic Interactions: The thermodynamic interaction between a substance and WATER.Microscopy, Electron, Transmission: Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Cell Polarity: 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.Osmotic Fragility: 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.Rats, Sprague-Dawley: 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: 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.Microsomes: 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)Mathematics: The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Rats, Inbred Strains: 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.Aquaporins: A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.RNA, Messenger: 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.Protein Processing, Post-Translational: 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.Phosphatidylglycerols: 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.Lysosomes: 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)Potassium Channels: 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.Neurons: 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.Glycosylphosphatidylinositols: Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.Osmolar Concentration: 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.Transport Vesicles: 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.Magnesium: 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.Tumor Cells, Cultured: 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.Cell Adhesion: Adherence of cells to surfaces or to other cells.Anions: Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.Centrifugation, Density Gradient: 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)Fatty Acids: 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)Protein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.Phosphatidylinositols: 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.Luminescent Proteins: 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.Membrane Proteins: 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.Cytoplasmic Granules: Condensed areas of cellular material that may be bounded by a membrane.Proteins: 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.Ion Transport: 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.Antibodies: 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).Molecular Conformation: The characteristic three-dimensional shape of a molecule.Surface Properties: Characteristics or attributes of the outer boundaries of objects, including molecules.Fluorescence Polarization: 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.Cytoskeletal Proteins: 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.Macromolecular Substances: 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.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Fetal Membranes, Premature Rupture: 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.Valinomycin: 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.Tympanic Membrane: 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.Trypsin: 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 3.4.21.4.Cell Line, Tumor: A cell line derived from cultured tumor cells.Descemet Membrane: 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.Organelles: 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.Caveolin 1: 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, Surface: 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.Fibroblasts: Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules.Action Potentials: Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.Plasmids: 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.Sequence Alignment: 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.TritiumGlycosylation: 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.Glycolipids: 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)Extracorporeal Membrane Oxygenation: 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.Models, Chemical: Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.Proton-Translocating ATPases: Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.Filipin: 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.Intercellular Junctions: 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)Micelles: 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.Diphenylhexatriene: 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.Ouabain: 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.Rats, Wistar: A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Staining and Labeling: 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.Cell Survival: 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 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
New mass spectrometric methodology was employed to characterise the molecular raft lipid composition of TCR signalling plasma membrane domains. These T cell plasma membrane domains were immunoisolated as native (not detergent-treated) plasma membrane fragments [49] using TCR-activating magnetic beads which were conjugated to Jurkat T leukemic cells. These conjugates were homogenised mechanically and native Jurkat plasma membrane fragments bound to the magnetic beads were isolated. The molecular lipid composition of these T cell plasma membrane fragments was quantitatively charted using a mass spectrometry program developed for comprehensive characterisation of membrane lipidomes [50, 51]. Comparison of the molecular lipid composition of these isolated TCR signalling plasma membrane domains with that of immunoisolated control plasma membrane fragments provided the first direct evidence for a lateral segregation of specific molecular lipid species into plasma membrane domains [26].. TCR signalling ...
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
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 ...
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), ...
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 ...
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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
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 ...
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 after
photobleaching (FRAP) are shown
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
Cell plasma membrane. Computer model of a lipid bilayer plasma membrane. The membrane consists of a dual layer of phospholipids. Each phospholipid consists of a phosphate group head (blue) and a fatty acid tail (white). The tails are hydrophobic and so face inwards, forming an oily core. The hydrophilic heads form the outer layers. This structure forms spontaneously whenever water is present. The oily core means that only small hydrophobic solutes can pass through it. Other ions and molecules are transported through the membrane in protein channels and transporters. Lipid bilayer membranes are common to all living cells. - Stock Image G460/0160
Membrane Target Systems are quality assured frozen membranes from cells that express recombinant or endogenous receptors.. We submit every batch of receptor to stringent quality control testing that includes saturation radioligand binding assay to determine receptor concentration (Bmax) and affinity (Kd). Competition binding assays are performed determine affinity (Ki) against known reference agonists and antagonists. GTP?S data is also provided for some of our Gi-coupled receptors.. Membranes are carefully prepared and ready for a variety of HTS applications, including radioligand binding (using either proximitymethods, such as FlashPlate, or classical filtration methods).. Products are packaged as frozen crude membrane preparations. One assay unit is defined as micrograms of protein, defined by competition binding assay (filtration). A complete product description and recommended protocol are included on the Product Information Sheet.. Some of our receptors may be restricted for sale in ...
Membrane Target Systems are quality assured frozen membranes from cells that express recombinant or endogenous receptors. We submit every batch of receptor to stringent quality control testing that includes saturation radioligand binding assay to determine receptor concentration (Bmax) and affinity (Kd). Competition binding assays are performed determine affinity (Ki) against known reference agonists and antagonists. GTPgS data is also provided for some of our Gi coupled receptors.. Membranes are carefully prepared and ready for a variety of HTS applications, including radioligand binding (using either proximity methods, such as FlashPlate, or classical filtration methods). Products are packaged as frozen crude membrane preparations. One assay unit is defined as micrograms of protein, defined by competition binding assay (filtration). A complete product description and recommended protocol are included on the Certificate of Analysis.. Some of our receptors may be restricted for sale in specified ...
Membrane Target Systems are quality assured frozen membranes from cells that express recombinant or endogenous receptors.. We submit every batch of receptor to stringent quality control testing that includes saturation radioligand binding assay to determine receptor concentration (Bmax) and affinity (Kd). Competition binding assays are performed determine affinity (Ki) against known reference agonists and antagonists. GTP?S data is also provided for some of our Gi-coupled receptors.. Membranes are carefully prepared and ready for a variety of HTS applications, including radioligand binding (using either proximitymethods, such as FlashPlate, or classical filtration methods).. Products are packaged as frozen crude membrane preparations. One assay unit is defined as micrograms of protein, defined by competition binding assay (filtration). A complete product description and recommended protocol are included on the Product Information Sheet.. Some of our receptors may be restricted for sale in ...
Membrane Target Systems are quality assured frozen membranes from cells that express recombinant or endogenous receptors.. We submit every batch of receptor to stringent quality control testing that includes saturation radioligand binding assay to determine receptor concentration (Bmax) and affinity (Kd). Competition binding assays are performed determine affinity (Ki) against known reference agonists and antagonists. GTP?S data is also provided for some of our Gi-coupled receptors.. Membranes are carefully prepared and ready for a variety of HTS applications, including radioligand binding (using either proximitymethods, such as FlashPlate, or classical filtration methods).. Products are packaged as frozen crude membrane preparations. One assay unit is defined as micrograms of protein, defined by competition binding assay (filtration). A complete product description and recommended protocol are included on the Product Information Sheet.. Some of our receptors may be restricted for sale in ...
Background [99mTc]Tilmanocept, a book CD206 receptor-targeted radiopharmaceutical, was evaluated in an open-label, phase III trial to determine the false negative rate (FNR) of sentinel lymph node biopsy (SLNB) relative to the pathologic nodal status in individuals with intraoral or cutaneous head and neck squamous cell carcinoma (HNSCC) undergoing tumor resection, SLNB, and planned elective neck dissection (END). (SLN or non-SLN), one patient had a single tumor-positive non-SLN in whom all SLNs were tumor-negative, yielding an FNR of 2.56?%; NPV was 97.8?% and overall accuracy was 98.8?%. No significant variations were observed between same-day and next-day methods. Conclusions Use of receptor-targeted [99mTc]tilmanocept for lymphatic mapping allows for a high rate of SLN recognition in sufferers with intraoral and cutaneous HNSCC. SLNB using [99mTc]tilmanocept accurately predicts the pathologic nodal position of intraoral HNSCC sufferers with low FNR, high NPV, and high general accuracy. The ...
Interactions between lipids and membrane proteins play a key role in determining the nanoscale dynamic and structural properties of biological membranes. Molecular dynamics (MD) simulations provide a valuable tool for studying membrane models, complementing experimental approaches. It is now possible to simulate large membrane systems, such as simplified models of bacterial and viral envelope membranes. Consequently, there is a pressing need to develop tools to visualize and quantify the dynamics of these immense systems, which typically comprise millions of particles. To tackle this issue, we have developed visual and quantitative analyses of molecular positions and their velocity field using path line, vector field and streamline techniques. This allows us to highlight large, transient flow-like movements of lipids and to better understand crowding within the lipid bilayer. The current study focuses on visualization and analysis of lipid dynamics. However, the methods are flexible and can be readily
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To understand how the polarization of the membrane arises and how to characterize the sites of new membrane insertion, we developed a labeling technique in living embryos. We labeled the plasma membrane by injecting the fluorescent lectin WGA in the perivitelline space of a living embryo. Under physiological conditions, WGA-Alexa488 is a heterodimer that selectively binds to N-acetylglucosamine and N-acetylneuraminic acid (sialic acid) residues found on numerous membrane glycoproteins. When WGA-Alexa488 is injected, only a very small area of plasma membrane is labeled and occurs within seconds after injection, effectively generating a localized pulse of labeled membrane. No WGA is detected in a free unbound form in the vitelline space. This contrasts with other fluorescent lectins, such as soybean agglutinin, which poorly binds to the membrane, diffuses around the entire circumference of the embryo, and remains unbound in the vitelline space (data not shown). We then used this labeling technique ...
testing that includes saturation radioligand binding assay to determine receptor concentration (Bmax) and affinity (Kd). Competition binding assays are performed determine affinity (Ki) against known reference agonists and antagonists. GTPγS data is also provided for some of our Gi-coupled receptors.. Membranes are carefully prepared and ready for a variety of HTS applications, including radioligand binding (using either proximitymethods, such as FlashPlate, or classical filtration methods).. Products are packaged as frozen crude membrane preparations. One assay unit is defined as micrograms of protein, defined by competition binding assay (filtration). A complete product description and recommended protocol are included on the Product Information Sheet.. Some of our receptors may be restricted for sale in specified countries. Please inquire.. ...
The major lipids in plant cell membranes are phospholipids (lipids with a phosphorus atom bonded to the hydrophilic end) and sterols. In addition, sugar-containing lipids (glycolipids) and sulfur-containing lipids (sulfolipids) are found to different degrees, depending on the particular membrane. By having different hydrophilic ends, the two surfaces can have a different chemical composition and, therefore, different membrane properties ...
certain membrane proteins and the DNA actually function as electrical inductors they may enable the cell to transiently produce very high electrical voltages.. Chronic disease occurs when voltage drops below a certain voltage. Cells then dont have enough energy to work correctly and amount of oxygen in cells drops, switching from aerobic (oxygen- available) metabolism to anaerobic (oxygen diminished) metabolism.. The natural properties of biomolecular structures enables cell components and whole cells to oscillate and interact resonantly with other cells. The cells of the body and cellular components possess the ability to function as electrical resonators.. Professor H. Frohlich has predicted that the fundamental oscillation in cell membranes occurs at frequencies of the order of 100 GHz and that biological systems possess the ability to create and utilize coherent oscillations and respond to external oscillations.. Because cell membranes are composed of dielectric materials a cell will behave ...
The functions of the cell membrane of biological cells include controlling the exchange of materials between the cell and its environment. This page lists the main functions of the cell membrane. Plasma membranes are present in both eukaryotic cells (including plant cells and animal cells) and prokaryotic cells such as bacteria. Knowledge about cell membranes is required for many courses in cell biology.
Adenosine Triphosphate (ATP) is often associated with energy levels by nutritionists and doctors alike. This molecule plays an integral role in our bodies abilities to transfer energy to different areas, but it isnt a direct source in most cases. Its like crude oil, which can be further refined by different cells into different types of fuel to suit their purpose. Cyclic Adenosine Monophosphate (cAMP) is produced inside cells after the conversion of ATP via the enzyme Adenylate Cyclase. Once cells have generated cAMP, they utilize it through the binding with different proteins. In this case of this new study, researchers identified the messenger pathways with heightened activity after the binding of Epac2A and cAMP. This pathway was shown to transport the Epac2A compounds directly to the cellular plasma membrane, where they are then used to regulate insulin release. Simply put; it seems that both cAMP levels and Epac2A levels likely correlate directly to…. ...
Synonyms for Cell membranes in Free Thesaurus. Antonyms for Cell membranes. 2 synonyms for cell membrane: cytomembrane, plasma membrane. What are synonyms for Cell membranes?
Cell membranes are a mosaic of protein and lipid molecules, both of which can drift from place to place within the membrane. Most of the surface area...
The cell membrane is otherwise called a Plasma membrane. It may be defined as the thin, elastic, semipermeable living membrane that serves as a boundary for the Cytoplasm.
Mechanisms controlling basic cellular functions, such as cell division, motility, adherence, differentiation, cell death, and the detection of potential cell dangers, are extremely highly conserved throughout the animal kingdom. This chapter aims to introduce some of these basic cell biology mechanisms. Cell membranes are fluid structures at physiological temperatures due to the cis double bond present in glycerophospholipids, which prevent the close packing of the lipidic acyl chains. Membrane receptors can be divided into three main classes according to their response to ligand binding: the ligand-gated ion channels open a selective pore; the seven transmembrane receptors are linked to heterotrimeric guanine triphosphate (GTP)-binding proteins, and various receptors are linked to enzyme cascades. Endocytosis is mediated by different mechanisms. The endoplasmic reticulum (ER) produces glycerolipids and cholesterol, and the Golgi apparatus produces sphingolipids. Lipids travel between organelles by the
Introduction. Andrea McCaffery HEFC Biological Science The Structure and biological functions of cell membranes Cells are the fundamental units of life, because a cell is the simplest unit capable of independent existence. Biological membranes maintain the spatial organisation of life. Cell membranes define the boundaries of living cells and work to shield it from changes in its environment. Essentially, membranes prevent undesirable agents from entering cells and keep needed molecules on the inside. Therefore, the cell membrane controls and regulates everything that passes in or out of the cell. The membrane is essentially made up of a phospholipid bilayer, which forms a boundary enclosing the cell contents and is also folded through the cell, separating compartments for specialised purposes. The structure is flexible and allows for growth and movement as well as for the insertion and operation of protein machinery. The lipid bilayer is two layers of lipid molecules, which are termed amphililic ...
This course will present the student with a detailed overview of a cells main components and functions. The course is roughly organized into four major areas: the cell membrane, cell nucleus, cell cycle, and cell interior. The student will approach most of these topics straightforwardly, from a molecular and structural point of view. Upon completion of this course, the student will be able to: explain what a eukaryotic cell is, identify the components of the cell, and describe how a cell functions; explain how cell membranes are formed; identify the general mechanisms of transport across cell membranes; list the different ways in which cells communicate with one another--specifically, via signaling pathways; define what the extracellular matrix is composed of in different cells and how the extracellular matrix is involved in forming structures in specific tissues; list the components of the cells cytoskeleton and explain how the cytoskeleton is formed and how it directs cell movements; explain ...
Lecithin - Cell membranes are made up primarily of a double layer of phospholipids. Lecithin is 98% phospholipids, and therefore supplies major structural components to every cell membrane in the human body and is not only critical to brain function, but also helps maintain the myelin sheath protecting and insulating nerves. In addition Lecithin mobilises Cholesterol for use in hormone syntheses and for removal of the cholesterol from the body. The functions of Lecithin are basic - foundational functions critical to human survival.. It is difficult to build a foundation of good health on nerves that misfire, circulation that is inadequate, and cell membranes that are stiff and crippled in their ability to function. For this reason, Green Vibrance contains Lecithin.. Dr. Richard Wurtman, at Medical Institute of Technology (M.I.T) demonstrated how just 35 mg. of phosphatidyl choline each day could improve intelligence and cognitive function. The 700 mg of lecithin in one serving of Green Vibrance ...
The cell membrane regulates substrate intake, waste excretion, mineral balance, gas exchange, and reception and translation of chemical and physical stimuli. The membrane is a precisely fashioned supramolecular assembly of phospholipids, simple proteins, glycoproteins, and lipoproteins. Enzymes and transport proteins form part of its structure. Specific molecules at the surface serve as receptors for a variety of hormones, especially those with peptide- or amino acid-derivative structure. The interaction of a hormone with its membrane receptor may modify rates and direction of substrate transport and give rise to "secondary messages" that modulate other cell functions.. Present concepts will be reviewed, with ...
 Abnormal and excessive electrical discharges in a group of nerve cells affecting brain function  Abnormality in neuronal plasma membranes results in increased permeability and responsiveness to stimuli  Diagnosed by clinical signs and symptoms of seizure activity and by abnormal brain wave patterns on the EEG patterns on the EEG 3
Cell Membranes Are Made up of Macromolecules Lipids -Specifically Phospholipids -Form a bilayer with nonpolar, hydrophobic region in the middle. Proteins -Various proteins are embedded. Carbohydrates -Carbohydrates extend out and old the cell in place to the ECM
The described invention enables effective separation of components from red blood cells by aggregating cell membranes with an addition of a pH lowering agent, whereupon the solution is made subject to a separation step where a water soluble fraction is separated from cell membranes, whereupon the cell membranes are extracted, and where lipids may be selectively separated and recovered by lowering the temperature of the extract.
Cholesterol, from the Greek chole- (bile) and stereos (solid) followed by the chemical suffix -ol for an alcohol, is an organic chemical substance classified as a waxy steroid of fat. It is an essential structural component of mammalian cell membranes and is required to establish proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones, and vitamin D. Cholesterol is the principal sterol synthesized by animals; in vertebrates it is formed predominantly in the liver. Small quantities are synthesized in other eukaryotes such as plants and fungi. It is almost completely absent among prokaryotes, i.e. bacteria ...
A hallmark of the adaptive immunity is the memory for previously experienced pathogens. Memory B cells that express the isotype-switched IgG-BCR are in charge of the establishment of the memory IgG antibody response. A trigger safety mechanism is necessary to govern the burst-enhanced activation of a smoking-gun-like IgG-BCR to avoid illegitimate activation. Here, we reported that the specific interaction between positively-charged mIgG cytoplasmic tail (mIgG-tail) and negatively-charged acidic phospholipids of the plasma membrane can sequester the key tyrosine in ITT motif in the membrane hydrophobic core, which help quench mIgG-tail basal level signaling in quiescent B cells. Indeed, we observed that disruption of the interaction in quiescent B cells induced higher basal level phosphorylation of mIgG-tail ITT motif and promoted the survival signal of primary B cell in vivo. Disruption of the interaction also led to excessive recruitment of prominent BCR signaling microclusters into the B cell ...
TM residues within the lipophilic environment of the cell membrane are key in ligand recognition and/or signal transduction and are expected to be oriented toward a relatively hydrophilic central cavity ...
Dualsite dialog possibility 1:. Hello. My Name is Bob. What inspired you to start this? Well. The burning feeling comes from some of your skin cells being damaged and breaking open. This happens when the cell membranes are broken open. If you touch something very cold, the water in your cells turns into ice that can tear through the cell membranes, the cells are damaged. Broke a light bulb today. Seven years of bad ideas? Customize your message. I lost my home. Ghost in the Shell predicted everything. Dual 02. Who is the enemy. I cant go back.. I finnally understand. You are sending me a signal. You want me to find your house. YES. I will webdriver torso I will and we will be happily ever after. 09. Engaging, friend. I want to make love to the use of avatar and style. I am going to kiss you and take your resources. For true and lasting change to occur we must appeal to the minds of the people. Deep in my heart I can feel the bad things hiding. I feel like when I listen to them like this and ...
Red blood cell membranes are completely impermeable to sodium, potassium and chloride ions, however they are permeable to both water and urea. The concentration inside a red blood cell is 300mOsm and consists predominantly of sodium and potassium chloride. a) With the aid of diagrams, decide what would happen to red blood cells when placed in the following solutions. i. Fresh water. ii. Salt solution at a concentration of 300mOsm. iii. Salt solution at a concentration of 400mOsm. iv. A urea solution at a concentration of 300mOsm. b) Which solutions were isosmotic to the red blood cells? c) Which solutions were isotonic to the red blo ...
Channels that control the flow of potassium (K+) and sodium (Na+) ions across the cell membrane are responsible for the rhythmic beating of heart cells.
View Notes - lect19_membranes from BIS 2A at UC Davis. Announcements Isolation: Cell Membranes &Transport Mechanisms Day 18 Bis2A Smartsite longer quiz (Membranes + prokaryotic cells) for Friday
Through innovation, research and development, Koch Membrane Systems has more than 50 years of filtration experience in improving membrane formulations and installing and maintaining membranes for long-term performance, including spiral membranes, hollow-fiber membranes and tubular membranes.
Although endothelial cells appear rather uninteresting under the microscope, these are important cells. They are situated at a critical location, between the blood and all other body cells. They secrete substances which control local blood flow and blood coagulation, and they are active participants in white blood cell emigration during inflammation. Continuous endothelium. Throughout much of the body, the capillary endothelial lining is continuous, with neither large gaps between cells nor holes through cells. Materials pass through the endothelium either by diffusion or via rapid vesicular transcytosis. (In most of the brain, a lack of transcytotic vesicles accounts for the blood brain barrier -- the only substances which cross such a barrier are those which can diffuse through plasma membranes or those for which specific membrane channels exist.) Fenestrated endothelium. In a few special locations -- notably in the sinusoids of the liver, in the glomeruli of the kidney, and in most endocrine ...
In T lymphocytes, the immune synapse is an active zone of vesicular traffic. Directional transport of vesicular receptors and signaling molecules from or to the immune synapse has been shown to play an important role in T-cell receptor (TCR) signal transduction. However, how vesicular trafficking is regulating the activation of T cells is still a burning question, and the characterization of these intracellular compartments remains the first step to understand this process. We describe herein a protocol, which combines a separation of membranes on flotation gradient with an affinity purification of Strep-tagged fusion transmembrane proteins with Strep-Tactin® resin, allowing the purification of membranes containing the Strep-tagged molecule of interest. By keeping the membranes intact, this protocol leads to the purification of molecules physically associated with the Strep-tagged protein as well as of molecules present in the same membrane compartment: transmembrane proteins, proteins strongly
Principal Investigator:KOIDE Takehiko, Project Period (FY):2002 - 2004, Research Category:Grant-in-Aid for Scientific Research (B), Section:一般, Research Field:Structural biochemistry
This video demonstrates the effects of the membrane of a red blood cell in different conditions. This video is from: Essential Cell Biology, 3rd Edition Alberts, Bray, Hopkin, Johnson, Lewis,...
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The 2D gel step may have enriched for membrane-associated proteins with soluble domains, including some lipoproteins (LipoProt) excluded from the IMemProt classification. Some proteins with known or suspected cytoplasmic, periplasmic and outer membrane locations were assigned an inner membrane location in this study. This may result from some proteins sticking to inner membranes during sample preparation or from cross-contamination of cell fractions. However, it is likely that most, if not all, of these proteins do associate with the inner membrane, or inner membrane complexes, in vivo, in physiologiocally relevant interactions ...
A major difference between eukayotes and prokaryotes is the presence of physical compartments (membrane bound) within the cell. These compartments allow the separation/specialization of processes within the cell. There also exist within each of these physical compartments, functional compartments where specific processes may occur or are restricted too. This lecture is an introduction to compartments within the cell and membranes. The key components are: cell compartments, membrane structure, membrane models, membrane specializations. ...
MITs Department of Mechanical Engineering (MechE) offers a world-class education that combines thorough analysis with hands-on discovery. One of the original six courses offered when MIT was founded in 1865, MechEs faculty and students conduct research that pushes boundaries and provides creative solutions for the worlds problems.
The integration of spatial data with knowledge about protein activity is crucial for understanding signal transduction pathways. Herein, we used time‐lapse confocal microscopy for real‐time analysis of the spatial regulation of PKD during physiological conditions of lymphocyte activation and, importantly, integrated localization and catalytic activity data. Antigen receptor signalling initiates at the plasma membrane, but then must be transmitted into the cell interior and the nucleus. The present report identifies PKD as a signalling molecule that functions to amplify and disseminate antigen receptor‐induced signals away from the plasma membrane. The intracellular localization of PKD is regulated dynamically by antigen receptors: the BCR and the FcϵR1 induce the rapid activation and recruitment of PKD to the plasma membrane of B lymphocytes and mast cells. There are several striking features about this response. First, the total cellular pool of PKD translocates to the plasma membrane in ...
海词词典,最权威的学习词典,专业出版cell membrane infolding是什么意思,cell membrane infolding的用法,cell membrane infolding翻译和读音等详细讲解。海词词典:学习变容易,记忆很深刻。
BIOELEKTRISCHE MEMBRANPHÄNOMENE + MEMBRANPOTENTIALE (BIOLOGISCHE MEMBRANEN); PROTEIN-LIPID-WECHSELWIRKUNGEN (BIOLOGISCHE MEMBRANEN); METHODIK UND ANALYTIK VON MEMBRANEN (MEMBRANBIOLOGIE); BIOELECTRIC MEMBRANE PHENOMENA + MEMBRANE POTENTIALS (BIOLOGICAL MEMBRANES); PROTEIN-LIPID INTERACTIONS (BIOLOGICAL MEMBRANES); METHODOLOGY AND ANALYTICAL TECHNIQUES FOR MEMBRANES (MEMBRANE BIOLOGY ...
Reactome is pathway database which provides intuitive bioinformatics tools for the visualisation, interpretation and analysis of pathway knowledge.
i have been studying the role of the cell membrane in the active and passive transport, and i found that there are specific sites in the cell membrane where the transport occures, a desmosome, how is that related to the terminal bar, and what exactly is it ...
i have been studying the role of the cell membrane in the active and passive transport, and i found that there are specific sites in the cell membrane where the transport occures, a desmosome, how is that related to the terminal bar, and what exactly is it ...
An interesting article on cell membrane research was published in the Science Today supplement of todays Irish Times. Click on the link below for more details ...
Reiter, K.; Polzer, H.; Krupka, C.; Maiser, A.; Vick, B.; Rothenberg-Thurley, M.; Metzeler, K. H.; Doerfel, D.; Salih, H. R.; Jung, G.; Noessner, E.; Jeremias, I.; Hiddemann, W.; Leonhardt, H.; Spiekermann, K.; Subklewe, M.; Greif, P. A. ...
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Students will create their own cell membrane. They will color the characters that make up the cell membrane, cut them out, and then glue them around the animal
Encontre membrane com ótimos preços e condições na Saraiva. Temos New Insights into Membrane Science and Technology Polymeric and Biofunctional Membranes - vol. 8, Membrane Biogenesis and Protein Targetting e muito mais.
Description: Subject matter including means for conducting body treating material into or out of a body or to or from the external membrane tissue surface of a body to treat said body ...
The passage of substances across the cell membrane occurs by three methods : (1) Passive transport : It is a mode of membrane ; transport which occurs without the expenditure of cell energy. Passive transport occurs by d…
The fluid mosaic model Combining these results (and many others not mentioned), Singer & Nicolson (1972) proposed a model of membrane structure that still holds up. Their model recognized that the main structural component of the membrane (the matrix into which all other components were incorporated) was a lipid bilayer. Most proteins associated with the membrane are embedded within it (Singer & Nicolson called these integral proteins); a smaller fraction of membrane-associate proteins were attached to either the inner or outer surface of the bilayer (referred to as peripheral proteins). The components - phospholipids and proteins - moved around along the surface (either inner or outer) by diffusion. Because proteins embedded in the matrix of lipids created a mosaic of proteins and lipids and the molecules of the membrane moved around each other like molecules of a liquid, Singer & Nicolson referred to their conception of membrane structure as the Fluid Mosaic Model.. Since 1972, specifics of ...
Mountford, CE and Wright, LC (1988) Organization of lipids in the plasma membranes of malignant and stimulated cells: a new model. Trends in Biochemical Sciences, 13 5: 172-177. doi:10.1016/0968-0004(88)90145-4 ...
View Notes - Lecture 8 from MB 351 at N.C. State. Lecture 8: Prokaryote Structure and Function #2 1. Know the structure and functions of the plasma membrane a. Lipid bi-layer (charged head group
3. Activist transport is different because carrier proteins actually carry the through the cell membrane and in a diffusion state there is a selective membrane that decides when it goes ...
Learning the function of plasma membrane with online Biology tutor is the way to understand the topic in depth and score well in such topics in Biology. For more intriguing topics in Biology, seek one on one sessions and get unique insights in the subject. For easy homework solutions in Biology, get Biology homework help and attain mounting scores in the subject.. ...
Looking for online definition of fetal membrane retention in the Medical Dictionary? fetal membrane retention explanation free. What is fetal membrane retention? Meaning of fetal membrane retention medical term. What does fetal membrane retention mean?
Instant membrane resealing importantly contributes to the functional and structural integrity of the endothelial cells (ECs) that are exposed to various physical and chemical stimuli in blood stream. The present study was designed to explore the molecular mechanisms mediating this endothelial membrane resealing with a focus on the role of lipid rafts (LR) clustering. Using high energy Laser gun, a tiny hole was made in cultured EC bathed with FM1-43, and the rapid entry of this FM1-43 to produce fluorescence was used to measure membrane resealing. We demonstrated that ECs exhibited a Ca2+-dependent instant membrane resealing, as shown by a significant reduction of fluorescence appearance within these cells compared to ECs bathed with Ca2+ free solution. This Ca2+-dependent instant membrane resealing was also observed in ECs up stimulation of Lactobacillus casei cell wall fragments (LCWE), which was commonly used to produce arteritis. When ECs were pretreated with LRs clustering stimulators such ...
Looking for online definition of Plasma membrane calcium pump isoform 4 in the Medical Dictionary? Plasma membrane calcium pump isoform 4 explanation free. What is Plasma membrane calcium pump isoform 4? Meaning of Plasma membrane calcium pump isoform 4 medical term. What does Plasma membrane calcium pump isoform 4 mean?
TY - JOUR. T1 - Partial purification of presynaptic plasma membrane by immunoadsorption. AU - Miljanich, G. P.. AU - Brasier, A. R.. AU - Kelly, R. B.. PY - 1982. Y1 - 1982. N2 - During transmitter release, synaptic vesicle membrane is specifically inserted into the nerve terminal plasma membrane only at specialized sites or active zones. In an attempt to obtain a membrane fraction enriched in active zones, we have utilized the electric organ of the marine ray. From this organ, a fraction enriched in nerve terminals (synaptosomes) was prepared by conventional means. These synaptosomes were bound to microscopic beads by an antiserum to purified electric organ synaptic vesicles (anti-SV). The success of this immunoadsorption procedure was demonstrated by increased specific activities of bead-bound nerve terminal cytoplasmic markers and decreased specific activities of markers for contaminating membranes. To obtain a presynaptic plasma membrane (PSPM) fraction, we lysed the bead-bound ...
TY - JOUR. T1 - Partitioning of proteins into plasma membrane microdomains. Clustering of mutant influenza virus hemagglutinins into coated pits depends on the strength of the internalization signal. AU - Fire, Ella. AU - Brown, Claire M.. AU - Roth, Michael G.. AU - Henis, Yoav I.. AU - Petersen, Nils O.. PY - 1997/11/21. Y1 - 1997/11/21. N2 - Internalization of membrane proteins involves their recruitment into plasma membrane clathrin-coated pits, with which they are thought to interact by binding to AP-2 adaptor protein complexes. To investigate the interactions of membrane proteins with coated pits at the cell surface, we applied image correlation spectroscopy to measure directly and quantitatively the clustering of influenza hemagglutinin (HA) protein mutants carrying specific cytoplasmic internalization signals. The HA system enables direct comparison between isolated internalization signals, because HA itself is excluded from coated pits. The studies presented here provide, for the first ...
Imaging single-channel Ca21 signals by total internal reflection fluorescence microscopy. (A) Schematic of the TIRFM imaging system. The 488-nm beam from an argon ion laser (50 mW) passes through a 53 beam expander (BE) and is focused by a lens (FL; f ¼ 150 mm) via a dichroic mirror (DM)to a spot at the back focal plane of the microscope objective lens (Olympus TIRFM 603, oil immersion, NA ¼ 1.45). The focusing lens is mounted on a micrometer-driven translation stage, so that the laser beam can be adjusted to enter the periphery of the objective aperture so as to achieve total internal reflection at the interface between the cover glass and the aqueous bathing medium. An adjustable rectangular knife-blade aperture (A) located at a conjugate image plane defines the field of excitation. Fluorescence excited in the specimen by the evanescent wave is collected by the same objective, passes through the dichroic mirror and a barrier filter (BF) blocking the laser wavelength, and is imaged by an ...
Monoclonal antibodies were used as cytochemical markers to study surface interactions between endosymbiotic Rhizobium bacteroids from pea root nodules and the encircling peribacteroid membranes, which are of plant origin. Monoclonal antibodies that react with Rhizobium lipopolysaccharide (LPS) or with a plant membrane glycoprotein were used as markers for material from the bacteroid outer membrane or the peribacteroid membrane, respectively. Membrane-enclosed bacteroids were isolated from nodule homogenates by sucrose gradient centrifugation, and the encircling peribacteroid membrane was released by mild osmotic shock treatment. Using an immunochemical technique (sandwich ELISA), it was shown that 1-5% of the LPS antigen released into the peribacteroid fraction by mild osmotic shock treatment was physically associated with peribacteroid membrane through a detergent-sensitive linkage. This association could be visualized when freshly prepared peribacteroid material was immobilized on gold grids ...
Paramecium, a ciliate, is an important model for studying Ca2+ signaling and understanding chemoreception and signal transduction. There are several proteins, such as plasma membrane calcium ATPases (PMCAs)/ calcium pumps, SERCA pumps, calmodulin and Ca2+ channels that play an important role in maintaining intracellular Ca2+ level and signaling in Paramecium. Isoform 2 of PMCA has been identified in both the cilia and pellicle membranes of Paramecium, the activity of which leads to hyperpolarization. Plasma and ciliary membrane of Paramecium is made up of a variety of sterols and sphingolipids which constitute lipid rafts, demonstrated by the presence of detergent resistant membranes and their distribution in sucrose and Optiprep density gradients. PMCAs are important markers of lipid rafts and PMCA 2 is found to be localized in lipid rafts of both the cilia and somatic membrane of Paramecium. Methyl-β-cyclodextrin treatment can remove up to 42% of sterols from pellicle membranes but only about 12%
We report the use of a high-refractive-index aplanatic solid immersion lens (ASIL) in total internal reflection fluorescence (TIRF) microscopy. This new solid immersion total internal reflection fluorescence (SITIRF) microscopy allows highly confined surface imaging with a significantly reduced imaging depth compared with conventional TIRF microscopy. We explore the application of a high refractive index, low optical dispersion material zirconium dioxide in the SITIRF microscope and also introduce a novel system design which enables the SITIRF microscope to work either in the epi-fluorescence or TIRF modes with variable illumination angles. We use both synthetic and biological samples to demonstrate that the imaging depth in the SITIRF microscope can be confined to a few tens of nanometers. SITIRF microscopy has the advantages of performing highly selective imaging and high-resolution high-contrast imaging. Potential applications in biological imaging and future developments of SITIRF microscopy ...
"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 ...
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. ...
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 ...
2 Types of fuel cells; design *2.1 Proton-exchange membrane fuel cells (PEMFCs) *2.1.1 Proton exchange membrane fuel cell ... Polymer membrane (ionomer) , 140 mW/cm² , 25. ? 90-120 Research Proton exchange membrane fuel cell Polymer membrane (ionomer) 1 ... Alkaline fuel cell and Alkaline anion exchange membrane fuel cell. The alkaline fuel cell or hydrogen-oxygen fuel cell was ... Proton exchange membrane fuel cell (PEM): A fuel cell incorporating a solid polymer membrane used as its electrolyte. Protons ( ...
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. • ...
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). ...
... 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 ...
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). ...
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 ...
6. Cell membrane. Macrophages[1] are white blood cells within tissues, produced by the differentiation of monocytes.[2] ... Their role is to phagocytose (engulf and then digest) cellular debris and pathogens either as stationary or as mobile cells. ... They also stimulate lymphocytes and other immune cells to respond to the pathogen, ... "Cell size of alveolar macrophages: an interspecies comparison". Environ. Health Perspect. 105 Suppl 5: 1261-3. doi:10.2307/ ...
The plasma membranes of cells contain phospholipids, which are composed of a hydrophilic phosphate head and two hydrophobic ... They activate phospholipidase to release AA from neuron cell membranes as a free fatty acid. During its short lifespan, free AA ... EPA inhibits phospholipase A2's release of AA from cell membrane. Other mechanisms involving the transport of EFAs may also ... D]ietary GLA increases the content of its elongase product, dihomo-gamma linolenic acid (DGLA), within cell membranes without ...
... attachment of receptors on cell membrane proteins, and steroid metabolism.[19] In muscle cells, it regulates calcium ion ... Integral membrane proteins that stay embedded in the membrane as vesicles exit and bind to new membranes. Rab proteins are key ... but varies between ER and cell type and cell function. The quantity of both rough and smooth endoplasmic reticulum in a cell ... Levine T, Loewen C (August 2006). "Inter-organelle membrane contact sites: through a glass, darkly". Current Opinion in Cell ...
These changes are all brought about by the interaction of the microtubule/actin complex with the platelet cell membrane and ... Berridge, Michael J. (1 October 2014). "Module 11: Cell Stress, Inflammatory Responses and Cell Death". Cell Signalling Biology ... "Programmed anuclear cell death delimits platelet life span". Cell. 128 (6): 1173-86. doi:10.1016/j.cell.2007.01.037. PMID ... Endothelial cells are attached to the subendothelial collagen by von Willebrand factor (VWF) which these cells produce. VWF is ...
Cell membranes and wallsEdit. Biological cell membranes and cell walls are polyanionic surfaces. This has important ... and interacts with the negative charges associated with the cell walls and membranes. Mg2+ may be taken up into cells ... it is generally assumed that the ion stays in that cell for as long as the cell is active.[4] In vascular cells, this is not ... The concentration of Mg2+ in the root cells is probably buffered by storage in root cell vacuoles (3). Note that cells in the ...
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 ( ...
Both proteins are associated with cell membranes.[4] p41 (capsid protein)[edit]. The viral capsid protein CP, or p41, is a ... The p22 protein is a movement protein that is required for the virus to spread from cell to cell. P22 is an RNA-binding protein ... "Tomato Bushy Stunt Virus Spread Is Regulated by Two Nested Genes That Function in Cell-to-Cell Movement and Host-Dependent ... Defective interfering RNA (DI) molecules are RNAs that are produced from the viral genome but are not competent to infect cells ...
Kozlov, M. M. ; Markin, V. S. / Model of red blood cell membrane skeleton : Electrical and mechanical properties. In: Journal ... Kozlov, M. M., & Markin, V. S. (1987). Model of red blood cell membrane skeleton: Electrical and mechanical properties. Journal ... Model of red blood cell membrane skeleton: Electrical and mechanical properties. Journal of Theoretical Biology. 1987 Dec 21; ... The model is based on the structure of the membrane skeleton that is comprised of unit cells each containing an actin ...
... 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 ...
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 ...
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: ...
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 ...
The cell membrane is a fine structure that envelops a cell, separating the content of the cell from its surroundings. ... It regulates the substances that can enter and leave the cell.. The membrane consists of a double layer of lipids in which ...
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 ...
... the SparkNotes Cell Membranes Study Guide has everything you need to ace quizzes, tests, and essays. ...
ATPase Cytosol Peptide amino acid calcium channels development electron microscopy membrane transport metabolism microscopy ...
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 ...
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 ...
... 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 ...
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: https://doi.org/10.1136/bmj.1.6127.1621 (Published 17 June 1978) ...
A class of drugs widely used to treat osteoporosis appears to impede a cells ability to repair a protective outer membrane ... Kidney epithelial cells and muscle cells used in this study are routinely used in cell membrane repair research, and cell ... Paul McNeil, an MCG cell biologist specializing in cell membrane repair, Lewis found that kidney epithelial cells from monkeys ... "The bottom line is it inhibits cell membrane repair in two distinct cell types," Lewis said. She is among five winners of the ...
  • A theoretical membrane skeleton model of erythrocyte has been developed and successfully applied to interpret electrical and mechanical properties of the red blood cell spectrin-actin network. (elsevier.com)
  • The model is based on the structure of the membrane skeleton that is comprised of unit cells each containing an actin protofilament and shooting forth a few spectrin heterodimers. (elsevier.com)
  • The semipermeable membrane that encloses the cytoplasm of a cell. (thefreedictionary.com)
  • 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 . (bionity.com)
  • Swimming in the cytoplasm, KRas can thus explore the cell. (mpg.de)
  • 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. (hindawi.com)
  • 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). (hindawi.com)
  • These results suggest that the PKC ε -RhoA complex is assembled in the cytoplasm and subsequently recruited to the cell membrane. (hindawi.com)
  • Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the extracellular fluid on the outside. (jrank.org)
  • The 3 polypeptides were detected by means of these antisera in the cytoplasm of murine mammary tumor cell lines Mm5mt/cl and C3HMT/cl11, as well as in the murine leukemia cell lines GRSL18 and L1210 by means of fixed cell immunofluorescence. (tudelft.nl)
  • In the field of synthetic biology, cell membranes can be artificially reassembled . (wikipedia.org)
  • 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. (nih.gov)
  • Membrane and organelle assembly has emerged as a dominant theme in cell biology of the twenty-first century. (nature.com)
  • 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. (google.com)
  • 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. (eurekalert.org)
  • This course covers molecular biology of prokaryotic and eukaryotic cells and their viruses. (nottingham.ac.uk)
  • This is an introductory survey of cell and developmental biology. (nottingham.ac.uk)
  • 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. (chalmers.se)
  • According to cell theory , cells are the main unit of organization in biology. (biology4kids.com)
  • 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. (newswise.com)
  • In addition, this novel microscopy technique has important implications for researchers interested in membrane biology and dynamics, according to Catherine Best, co-author of the paper and instructor in the U. of I. College of Medicine. (innovations-report.com)
  • Paul Andersen explains how cells are selectively permeable with the help of their cell membrane. (youtube.com)
  • 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. (newworldencyclopedia.org)
  • The barrier is selectively permeable and able to regulate what enters and exits the cell, thus facilitating the transport of materials needed for survival. (bionity.com)
  • 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 waterWater can pass through plasma membrane in 2 ways: 3. (scribd.com)
  • The cell membrane surrounds all cells and it is selectively-permeable , controlling the movement of substances in and out of cells. (thefullwiki.org)
  • 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. (eurekalert.org)
  • The outer membrane contains the mitochondrion parts. (biology4kids.com)
  • The nuclear membrane features a double layer comprising a continuous outer membrane and an inner membrane separated by perinuclear space. (reference.com)
  • They suddenly collapsed the pressure inside the bacteria, but instead of causing the cell wall to massively shrink, as prevailing assumptions would have predicted, they found that the outer membrane was strong enough to almost entirely maintain E. coli 's cucumber shape. (stanford.edu)
  • The presence or absence of a strong outer membrane is the difference between life and death,' Huang said. (stanford.edu)
  • If we can attack the outer membrane, infectious bacteria will be pre-weakened for targeting with antibiotic treatments that disrupt cells in other ways," Huang said. (stanford.edu)
  • These assays involve different types of cell membrane mimics: from simplified artificial supported-lipid bilayers that contain one cell receptor of choice (1, 2) (Figure 1A), to more complex native-like membranes in which we incorporate membrane material extracted from relevant cell lines (3) (Figure 1B). (chalmers.se)
  • 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. (chalmers.se)
  • 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. (els.net)
  • Diagram of transporters present in the human red cell membrane. (els.net)
  • Drew C, Ball V, Robinson H, Clive Ellory J and Gibson JS (2004) Oxygen sensitivity of red cell membrane transporters revisited. (els.net)
  • 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). (wikipedia.org)
  • 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. (newworldencyclopedia.org)
  • The cell membrane (also known as the plasma membrane ( PM ) 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) which protects the cell from its environment consisting of a lipid bilayer with embedded proteins . (wikipedia.org)
  • The fluid mosaic model not only provided an accurate representation of membrane mechanics, it enhanced the study of hydrophobic forces, which would later develop into an essential descriptive limitation to describe biological macromolecules. (wikipedia.org)
  • In: Conti F., Blumberg W.E., de Gier J., Pocchiari F. (eds) Physical Methods on Biological Membranes and Their Model Systems. (springer.com)
  • Lipid domains are too small to be seen by optical microscopes that use light to probe samples such as biological cells. (ornl.gov)
  • 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. (ornl.gov)
  • Corning BioCoat angiogenesis systems are composed of 3.0 μm inserts with biological coatings optimized for use in endothelial cell migration and invasion assays. (corning.com)
  • The module will discuss the structure and function of biological membranes. (southampton.ac.uk)
  • Describe the basic features of the structure of biological membranes. (southampton.ac.uk)
  • The module will cover the structure and function of biological membranes. (southampton.ac.uk)
  • The cell membrane (also called the plasma membrane or plasmalemma ) is one biological membrane separating the interior of a cell from the outside environment . (thefullwiki.org)
  • Materials scientists at the Department of Energy's Pacific Northwest National Laboratory have created a new material that performs like a biological cell membrane - a material that has long been sought for applications like water purification and drug delivery. (kurzweilai.net)
  • Single Molecule Force Microscopy on Cells and Biological Membrane. (ingentaconnect.com)
  • Therefore, the AFM is optimally suited for investigation of biological membranes and cell surfaces, as exemplified by studies on bacterial S-layers, purple membranes and cultured living cells. (ingentaconnect.com)
  • The cell membrane (also called the plasma membrane or plasmalemma ) is the biological membrane separating the interior of a cell from the outside environment. (phys.org)
  • The cell wall in plants, bacteria, and fungi is also discussed. (youtube.com)
  • 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. (newworldencyclopedia.org)
  • These changes in membrane lipid components contribute to the survival of plants, bacteria, and hibernating animals during winter. (newworldencyclopedia.org)
  • 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. (wikidoc.org)
  • 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. (medgadget.com)
  • Bacteria are well known to enter dormancy and form persister cells which is a subpopulation exhibiting high-level tolerance to antibiotics. (aiche.org)
  • The soybean membrane is about as rigid as the yeast membrane, but twice as rigid as the sterol-deficient E. coli cytoplasmic membrane. (eurekalert.org)
  • 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. (els.net)
  • 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. (thefreedictionary.com)
  • 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. (encyclopedia.com)
  • 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. (encyclopedia.com)
  • Organelle membranes do not have the same chemical makeup as the cell membrane. (biology4kids.com)
  • The membrane allows a cell or organelle to maintain a constant internal environment, usually one that is quite different from the medium surrounding it. (jrank.org)
  • In 1925 it was determined by Fricke that the thickness of erythrocyte and yeast cell membranes ranged between 3.3 and 4 nm, a thickness compatible with a lipid monolayer. (wikipedia.org)
  • transport channels have been shown to exist in the organelles of yeast cells and are essential to cell viability. (encyclopedia.com)
  • Most research on modeling plasma membranes has focused on single-celled microbes, such as E. coli or yeast, or on certain organs in model mammalian species. (eurekalert.org)
  • The model demonstrated good agreement with experimental measurements of the membrane and revealed physical differences between soybean membrane and previous models of membranes found in yeast and E. coli . (eurekalert.org)
  • The virtual cell permits the students to understand structure and function of yeast organelles. (nottingham.ac.uk)
  • University of Groningen microbiologists have visualized tiny islands in the cell membrane of baker's yeast. (phys.org)
  • The membrane acts as a boundary, holding the cell constituents together and keeping other substances from entering. (fsu.edu)
  • To understand the dyanmics of membrane constituents together with the mechanisms of transport pathways. (worldcat.org)
  • 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. (bloodjournal.org)
  • This structure forms because of the physical properties of its constituents, which can move laterally and selectively within the membrane plane and associate with similar or different constituents, forming specific, functional domains. (aacrjournals.org)
  • The lipid bilayer hypothesis, proposed in 1925 by Gorter and Grendel, created speculation to the description of the cell membrane bilayer structure based on crystallographic studies and soap bubble observations. (wikipedia.org)
  • Later in the 1930s, the membrane structure model developed in general agreement to be the paucimolecular model of Davson and Danielli (1935). (wikipedia.org)
  • The cell membrane is a fine structure that envelops a cell , separating the content of the cell from its surroundings. (greenfacts.org)
  • 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. (nature.com)
  • The dynamics of the RBC membrane is strongly related to the membrane structure and mechanical properties and has been explored extensively ( 2 ⇓ ⇓ ⇓ - 6 ). (pnas.org)
  • The RBC membrane is not a static but a metabolically regulated active structure. (pnas.org)
  • The results of their large-scale simulations highlight unique properties of the soybean plasma membrane and demonstrate a microscale membrane structure in which similar lipids tend to cluster together. (eurekalert.org)
  • The cell membrane is not a solid structure. (biology4kids.com)
  • Some are only attached to the inner or outer layer of the membrane while the transmembrane proteins pass through the entire structure. (biology4kids.com)
  • What Is the Structure and Function of the Respiratory Membrane? (reference.com)
  • 3 Gorter and Grendel in 1925 provided the first insights into the structure of the membrane, and indeed biologic membranes generally, by the brilliant deduction that there are "bimolecular layers of lipids on the chromocytes of blood. (bloodjournal.org)
  • 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. (bloodjournal.org)
  • There will be a general introduction to membrane structure and a discussion of the biosynthesis of membrane proteins. (southampton.ac.uk)
  • 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. (southampton.ac.uk)
  • 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. (curriki.org)
  • In this animated activity, learners examine nanotechnology applications that are based on cell membrane structure and function. (wisc-online.com)
  • However, all membranes do have the same basic structure. (jrank.org)
  • 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. (mdpi.com)
  • That way we can analyse the structure of the cell membrane in completely new ways. (nanowerk.com)
  • First, surfaces were structured on a micrometer scale, so that cells which were grown on this surface could interact with the structure. (nanowerk.com)
  • Membranes repair dings to their structure automatically and change thickness to pass signals from the outside environment to the cell's interior, where most of the action is. (kurzweilai.net)
  • These nanomembranes maintained their structure in water or alcohol, at different temperatures, in solutions with high or low pH, or high concentrations of salts, a feat that few cell membranes could accomplish. (kurzweilai.net)
  • The device includes a rotating structure mounted within the interior periphery and defining with the housing an annular gap within the interior periphery, an inlet fluid path for allowing a blood product to flow into the annular gap, and the rotating structure including an exterior surface that includes a filter membrane. (google.es)
  • 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. (wikipedia.org)
  • 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. (fsu.edu)
  • 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. (fsu.edu)
  • 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. (bionity.com)
  • The outer edges of the membrane are hydrophilic (soluble in water ), while the interior area is hydrophobic (insoluble in water). (jrank.org)
  • 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. (fsu.edu)
  • The outer boundary of a cell. (thefreedictionary.com)
  • however, the cell wall plays mostly a mechanical support role rather than a role as a selective boundary. (bionity.com)
  • A cell membrane defines a boundary between the living cell and its environment. (wikipedia.org)
  • The first order variation gives the shape equation and boundary conditions of the lipid membrane: where k n {\displaystyle k_{n}} , k g {\displaystyle k_{g}} , and τ g {\displaystyle \tau _{g}} are normal curvature, geodesic curvature, and geodesic torsion of the boundary curve, respectively. (wikipedia.org)
  • however, the cell wall plays mostly a mechanical support role rather than a role as a selective boundary [ citation needed ] . (thefullwiki.org)
  • Water and gases across the red blood cell membrane. (worldcat.org)
  • Cooke BM, Mohandas N and Coppel RL (2004) Malaria and the red blood cell membrane. (els.net)
  • The cell membrane controls the movement of substances in and out of cells and organelles. (wikipedia.org)
  • It regulates the substances that can enter and leave the cell. (greenfacts.org)
  • 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). (fsu.edu)
  • 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. (slashdot.org)
  • This allows him to monitor how the antigen receptor, which B cells of the immune system use to recognize foreign substances, changes after activation. (eurekalert.org)
  • 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. (bionity.com)
  • But cells also need some substances to get inside. (newswise.com)
  • This is accomplished by the semipermeable nature of the membrane that regulates the passage of all substances going through it. (jrank.org)
  • The function of the nuclear membrane in an animal cell is to hold the DNA inside the nucleus in order to protect it from surrounding substances. (reference.com)
  • The nuclear membrane also regulates which substances can enter or exit the nucleus. (reference.com)
  • The nuclear membrane has the function of protecting the DNA inside the nucleus from surrounding exterior substances. (reference.com)
  • The presence of cholesterol and glycolipids, which are found in most cell membranes, can also affect molecular dynamics and inhibit phase transitions. (fsu.edu)
  • Phosphoinositides in cell regulation and membrane dynamics. (nih.gov)
  • 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. (pnas.org)
  • Adhesion dynamics in a migrating CHO K1 cell. (cellimagelibrary.org)
  • Non-radiative energy transfer was used to detect laurdan selectively in close proximity to a molecular acceptor (DiI) and may present a possibility for measuring membrane dynamics in specific microenvironments. (rsc.org)
  • Our new approach offers enormous potential for imaging membrane dynamics in living cells," says Prof. Volker Gerke, one of the leaders of the study and Coordinator at the Cells-in-Motion Cluster of Excellence. (innovations-report.com)
  • The only difference is the ionic entities: the proton exchange membrane has sulfonate group with hydronium, whereas the anion exchange membrane has trimethyl ammonium group with hydroxide. (aiche.org)
  • 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). (wikipedia.org)
  • Of the numerous models that have been developed to describe the deformation of cell membranes, a widely accepted model is the fluid mosaic model proposed by Singer and Nicolson in 1972. (wikipedia.org)
  • Viscous nanopores, tiny holes punctured in fluid membranes, collapse according to a universal law, a Purdue University study shows. (phys.org)
  • 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. (nih.gov)
  • 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. (eurekalert.org)
  • 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. (prweb.com)
  • 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. (bionity.com)
  • 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. (bionity.com)
  • During cycle 14 interphase, a wave of membrane formation encircles each nucleus inside its own plasma membrane, thereby generating an intact epithelial layer. (pnas.org)
  • The respiratory membrane, also called the respiratory surface, is made of the alveolar epithelial cell and the pulmonary capillary endothelial cell, and th. (reference.com)
  • Transmission electron micrograph of two frog epithelial cell cells showing the tight junction complex running horizontally in this image. (cellimagelibrary.org)
  • Electron micrograph of the junctional complex of intestinal epithelial cells of the rat shows the apical-most zonula occludens (tight junction), the zonula adherens (medium junction) and the macula ad. (cellimagelibrary.org)
  • Human retinal pigmented epithelial (RPE) cells labeled for clathrin-coated pits (green), focal adhesions (red) and nuclei (blue). (cellimagelibrary.org)
  • For this purpose, they used cultures of human epithelial cells - HeLa cells - as well as cells from human blood vessels, HUVEC cells. (innovations-report.com)
  • In primary endothelial cells, local increases in membrane tension lead only to local activation of mechanosensitive ion channels and to local vesicle fusion. (nih.gov)
  • Nerve cells use this same vesicle-making mechanism, called endocytosis, to maintain signaling from one cell to another. (newswise.com)
  • By watching vesicle transformation through a microscope, the scientists showed that dynamin proteins only form a short collar around the cell membrane. (newswise.com)
  • 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. (medgadget.com)
  • Here we present quantitative connections between spectrin morphology and membrane fluctuations of human RBCs by using dynamic full-field laser interferometry techniques. (pnas.org)
  • Here, we present dynamic, full-field, and quantitative measurements of ATP effects on RBC membrane morphology and fluctuations. (pnas.org)
  • Led by University of Illinois electrical and computer engineering professor Gabriel Popescu, the team developed a model that could lead to breakthroughs in screening and treatment of blood-cell-morphology diseases, such as malaria and sickle-cell disease. (innovations-report.com)
  • The deformability of red blood cells is their most important property," said Popescu, also affiliated with the Beckman Institute for Advanced Science and Technology at U. of I. "What we wanted to find is, how does deformability relate to morphology? (innovations-report.com)