Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
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.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
The motion of phospholipid molecules within the lipid bilayer, dependent on the classes of phospholipids present, their fatty acid composition and degree of unsaturation of the acyl chains, the cholesterol concentration, and temperature.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
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.
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.
Glycoproteins found on the membrane or surface of cells.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological 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).
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.
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.
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.
Established cell cultures that have the potential to propagate indefinitely.
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.
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.
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.
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.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
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.
Transport proteins that carry specific substances in the blood or across cell 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.
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)
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.
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.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
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)
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.
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.
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)
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Proteins found in any species of bacterium.
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.
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.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The sum of the weight of all the atoms in a molecule.
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.
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
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.
Minute projections of cell membranes which greatly increase the surface area of the cell.
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.
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)
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)
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.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
The 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)
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
The 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.
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)
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.
Elements of limited time intervals, contributing to particular results or situations.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
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).
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
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.
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.
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.
The ability of a substrate to allow the passage of ELECTRONS.
A fold of the mucous membrane of the CONJUNCTIVA in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the CORNEA.
The inner layer of CHOROID, also called the lamina basalis choroideae, located adjacent to the RETINAL PIGMENT EPITHELIUM; (RPE) of the EYE. It is a membrane composed of the basement membranes of the choriocapillaris ENDOTHELIUM and that of the RPE. The membrane stops at the OPTIC NERVE, as does the RPE.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
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.
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.
Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
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.
Proteins prepared by recombinant DNA technology.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
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.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
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.
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.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
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.
Proteins obtained from ESCHERICHIA COLI.
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.
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.
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.
The rate dynamics in chemical or physical systems.
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.
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)
Single membrane vesicles, generally made of PHOSPHOLIPIDS.
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.
Measurement of the intensity and quality of fluorescence.
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.
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.
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.
An oval semitransparent membrane separating the external EAR CANAL from the tympanic cavity (EAR, MIDDLE). It contains three layers: the skin of the external ear canal; the core of radially and circularly arranged collagen fibers; and the MUCOSA of the middle ear.
A 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.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
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).)
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
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)
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.
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.
Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.
A 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)
Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.
The thermodynamic interaction between a substance and WATER.
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)
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
A 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.
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
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.
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.
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.
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.
Ubiquitously expressed integral membrane glycoproteins found in the LYSOSOME.
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.
Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.
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.
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
The plasma membrane of the egg.
Calcium-transporting ATPases found on the PLASMA MEMBRANE that catalyze the active transport of CALCIUM from the CYTOPLASM into the extracellular space. They play a role in maintaining a CALCIUM gradient across plasma membrane.
The innermost membranous sac that surrounds and protects the developing embryo which is bathed in the AMNIOTIC FLUID. Amnion cells are secretory EPITHELIAL CELLS and contribute to the amniotic fluid.
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.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Proteins involved in the transport of specific substances across the membranes of the MITOCHONDRIA.
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)
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)
Cyclic GLUCANS consisting of seven (7) glucopyranose units linked by 1,4-glycosidic bonds.
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.-.
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.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
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.
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.
Cells that line the inner and outer surfaces of the body by forming cellular layers (EPITHELIUM) or masses. Epithelial cells lining the SKIN; the MOUTH; the NOSE; and the ANAL CANAL derive from ectoderm; those lining the RESPIRATORY SYSTEM and the DIGESTIVE SYSTEM derive from endoderm; others (CARDIOVASCULAR SYSTEM and LYMPHATIC SYSTEM) derive from mesoderm. Epithelial cells can be classified mainly by cell shape and function into squamous, glandular and transitional epithelial cells.
A 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.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
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.
The membrane system of the CELL NUCLEUS that surrounds the nucleoplasm. It consists of two concentric membranes separated by the perinuclear space. The structures of the envelope where it opens to the cytoplasm are called the nuclear pores (NUCLEAR PORE).
The relationship between the dose of an administered drug and the response of the organism to the drug.
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.
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.
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.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
A basement membrane in the cochlea that supports the hair cells of the ORGAN OF CORTI, consisting keratin-like fibrils. It stretches from the SPIRAL LAMINA to the basilar crest. The movement of fluid in the cochlea, induced by sound, causes displacement of the basilar membrane and subsequent stimulation of the attached hair cells which transform the mechanical signal into neural activity.
One or more layers of EPITHELIAL CELLS, supported by the basal lamina, which covers the inner or outer surfaces of the body.
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.
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.
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.
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.
Condensed areas of cellular material that may be bounded by a membrane.
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.
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.
Antibodies produced by a single clone of cells.
The characteristic three-dimensional shape of a molecule.
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.
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.
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.
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.
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.
Surface glycoproteins on platelets which have a key role in hemostasis and thrombosis such as platelet adhesion and aggregation. Many of these are receptors.
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.
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
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.
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.
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.
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.
Compounds containing carbohydrate or glycosyl groups linked to phosphatidylinositols. They anchor GPI-LINKED PROTEINS or polysaccharides to cell membranes.
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.
Membrane-limited structures derived from the plasma membrane or various intracellular membranes which function in storage, transport or metabolism.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
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
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
A fluorescent compound that emits light only in specific configurations in certain lipid media. It is used as a tool in the study of membrane lipids.
A fungal metabolite which is a macrocyclic lactone exhibiting a wide range of antibiotic activity.
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)
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.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
Tendency of fluids (e.g., water) to move from the less concentrated to the more concentrated side of a semipermeable membrane.
Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
Polymers of ETHYLENE OXIDE and water, and their ethers. They vary in consistency from liquid to solid depending on the molecular weight indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are NONOXYNOLS, OCTOXYNOLS, and POLOXAMERS.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
A phosphoinositide present in all eukaryotic cells, particularly in the plasma membrane. It is the major substrate for receptor-stimulated phosphoinositidase C, with the consequent formation of inositol 1,4,5-triphosphate and diacylglycerol, and probably also for receptor-stimulated inositol phospholipid 3-kinase. (Kendrew, The Encyclopedia of Molecular Biology, 1994)
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.
The process of cleaving a chemical compound by the addition of a molecule of water.
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.
A class of porins that allow the passage of WATER and other small molecules across CELL MEMBRANES.
Membranous cisternae of the CHLOROPLAST containing photosynthetic pigments, reaction centers, and the electron-transport chain. Each thylakoid consists of a flattened sac of membrane enclosing a narrow intra-thylakoid space (Lackie and Dow, Dictionary of Cell Biology, 2nd ed). Individual thylakoids are interconnected and tend to stack to form aggregates called grana. They are found in cyanobacteria and all plants.

Extra-vesicular binding of noradrenaline and guanethidine in the adrenergic neurones of the rat heart: a proposed site of action of adrenergic neurone blocking agents. (1/2566)

1 The binding and efflux characteristics of [14C]-guanethidine and [3H]-noradrenaline were studied in heart slices from rats which were pretreated with reserpine and nialamide. 2 Binding of both compounds occurred at extra-vesicular sites within the adrenergic neurone. After a brief period of rapid washout, the efflux of [14C]-guanethidine and [3H]-noradrenaline proceeded at a steady rate. The efflux of both compounds appeared to occur from a single intraneuronal compartment. 3 (+)-Amphetamine accelerated the efflux of [14C]-noradrenaline; this effect was inhibited by desipramine. 4 Unlabelled guanethidine and amantadine also increased the efflux of labelled compounds. Cocaine in high concentrations increased slightly the efflux of [14C]-guanethidine but not that of [3H]-noradrenaline. 5 Heart slices labelled with [3H]-noradrenaline became refractory to successive exposures to releasing agents although an appreciable amount of labelled compound was still present in in these slices. 6 It is suggested that [14C]-guanethidine and [3H]-noradrenaline are bound at a common extravesicular site within the adrenergic neurone. Binding of guanethidine to the extra-vesicular site may be relevant to its pharmacological action, i.e., the blockade of adrenergic transmission.  (+info)

The Saccharomyces cerevisiae CWH8 gene is required for full levels of dolichol-linked oligosaccharides in the endoplasmic reticulum and for efficient N-glycosylation. (2/2566)

The Saccharomyces cerevisiae mutant cwh8 was previously found to have an anomalous cell wall. Here we show that the cwh8 mutant has an N -glycosylation defect. We found that cwh8 cells were resistant to vanadate and sensitive to hygromycin B, and produced glycoforms of invertase and carboxypeptidase Y with a reduced number of N -chains. We have cloned the CWH8 gene. We found that it was nonessential and encoded a putative transmembrane protein of 239 amino acids. Comparison of the in vitro oligosaccharyl transferase activities of membrane preparations from wild type or cwh8 Delta cells revealed no differences in enzyme kinetic properties indicating that the oligosaccharyl transferase complex of mutant cells was not affected. cwh8 Delta cells also produced normal dolichols and dolichol-linked oligosaccharide intermediates including the full-length form Glc3Man9GlcNAc2. The level of dolichol-linked oligosaccharides in cwh8 Delta cells was, however, reduced to about 20% of the wild type. We propose that inefficient N -glycosylation of secretory proteins in cwh8 Delta cells is caused by an insufficient supply of dolichol-linked oligosaccharide substrate.  (+info)

Isolation and characterization of major intrinsic microsomal membrane proteins. (3/2566)

Treatment of the membrane matrix derived from hepatic microsomes with buffered 1 M urea resulted in the selective extraction of a group of proteins together with a portion of the membrane lipid. Thorough chemical characterization of this fraction has been performed, and the proteins have been fractionated by two different procedures. The first of these, preparative polyacrylamide gel electrophoresis, has produced five highly homogeneous membrane proteins which have been characterized with regard to molecular weight, electrophoretic behavior in five different polyacrylamide systems, NH2 terminus, relative carbohydrate content, isoelectric point, and amino acid composition. The five proteins of this group fell in the molecular weight range of 54,000 to 96,000 and had isoelectric points ranging from pH 4.9 to pH 6.7. Further fractionation of the urea-soluble proteins by gel filtration in a sodium dodecyl sulfate-containing medium resulted in the isolation of four homogeneous molecular weight classes of proteins which have been characterized with respect to various physicochemical parameters. The major membrane glycoprotein (apparent molecular weight, 171,000) was isolated by this procedure and found to contain approximately equal amounts of NH2-terminal glycine and serine. suggesting the presence of at least two polypeptide chains in this molecular weight region. From the urea-insoluble fraction of the membrane comprising approximately 80% of the total protein, five intrinsic polypeptides designated S-5 through S-9 were isolated. S-5 (54,000) and S-6 (49,000) represent the most prominent components in the microsomal membrane, accounting for close to 30% of the total protein. Also isolated and characterized is the smallest membrane protein (S-9), a hydrophobic polypeptide of molecular weight 16,000. All of the urea-insoluble proteins are glycoproteins, and S-7 (35,000) gives the second most intense stain for carbohydrate of all proteins in the microsomal membrane.  (+info)

Kinetic analysis of drug-receptor interactions of long-acting beta2 sympathomimetics in isolated receptor membranes: evidence against prolonged effects of salmeterol and formoterol on receptor-coupled adenylyl cyclase. (4/2566)

The long-acting beta2 sympathomimetics salmeterol and formoterol have been presumed to exert their prolonged action either by binding to an accessory binding site ("exo-site") near the beta2 adrenoceptor or by their high affinity for beta2 adrenoceptors and correspondingly slow dissociation. Whereas most studies with salmeterol had been done in intact tissues, which have slow diffusion and compartmentation of drugs in lipophilic phases, that restrict drug access to the receptor biophase, we used purified receptor membranes from rat lung and disaggregated calf tracheal myocytes as model systems. Binding experiments were designed to measure the slow dissociation of agonists by means of delayed association of (-)-[125I]iodopindolol. Rat lung membranes were pretreated with high concentrations of agonists (salmeterol, formoterol, isoprenaline) before dissociation was induced by 50-fold dilution. Half-times of association of (-)-[125I]iodopindolol remained unchanged compared with untreated controls, indicating that dissociation of agonists occurred in less than 2 min. Adenylyl cyclase experiments were designed to determine the on and off kinetics of agonists to beta2 adrenoceptors by measuring the rate of receptor-induced cyclic AMP (cAMP) formation. Experiments were performed in tracheal membranes characterized by high Vmax values of cAMP formation. Adenylyl cyclase activation occurred simultaneously with the addition of the agonist, continued linearly with time for 60 min, and ceased immediately after the antagonist was added. Similarly, when receptor membranes were preincubated in a small volume with high salmeterol concentrations, there was a linear increase in cAMP formation, which was immediately interrupted by a 100-fold dilution of the reaction mixture. This militates against the exo-site hypothesis. On the other hand, dissociation by dilution was much less when membranes were preincubated with a large volume of salmeterol at the same concentration, indicating that physicochemical effects, and not exo-site binding, underlie its prolonged mode of action.  (+info)

Biochemical and electrophysiological studies on the mechanism of action of PNU-151774E, a novel antiepileptic compound. (5/2566)

PNU-151774E [(S)-(+)-2-(4-(3-fluorobenzyloxy)benzylamino)propanamide methanesulfonate], a new anticonvulsant that displays a wide therapeutic window, has a potency comparable or superior to that of most classic anticonvulsants. PNU-151774E is chemically unrelated to current antiepileptics. In animal seizure models it possesses a broad spectrum of action. In the present study, the action mechanism of PNU-151774E has been investigated using electrophysiological and biochemical assays. Binding studies performed with rat brain membranes show that PNU-151774E has high affinity for binding site 2 of the sodium channel receptor, which is greater than that of phenytoin or lamotrigine (IC50, 8 microM versus 47 and 185 microM, respectively). PNU-151774E reduces sustained repetitive firing in a use-dependent manner without modifying the first action potential in hippocampal cultured neurons. In the same preparation PNU-151774E inhibits tetrodotoxin-sensitive fast sodium currents and high voltage-activated calcium currents under voltage-clamp conditions. These electrophysiological activities of PNU-151774E correlate with its ability to inhibit veratrine and KCl-induced glutamate release in rat hippocampal slices (IC50, 56.4 and 185.5 microM, respectively) and calcium inward currents in mouse cortical neurons. On the other hand, PNU-151774E does not affect whole-cell gamma-aminobutryic acid- and glutamate-induced currents in cultured mouse cortical neurons. These results suggest that PNU-151774E exerts its anticonvulsant activity, at least in part, through inhibition of sodium and calcium channels, stabilizing neuronal membrane excitability and inhibiting transmitter release. The possible relevance of these pharmacological properties to its antiepileptic potential is discussed.  (+info)

Localization and environment of tryptophans in soluble and membrane-bound states of a pore-forming toxin from Staphylococcus aureus. (6/2566)

The location and environment of tryptophans in the soluble and membrane-bound forms of Staphylococcus aureus alpha-toxin were monitored using intrinsic tryptophan fluorescence. Fluorescence quenching of the toxin monomer in solution indicated varying degrees of tryptophan burial within the protein interior. N-Bromosuccinimide readily abolished 80% of the fluorescence in solution. The residual fluorescence of the modified toxin showed a blue-shifted emission maximum, a longer fluorescence lifetime as compared to the unmodified and membrane-bound alpha-toxin, and a 5- to 6-nm red edge excitation shift, all indicating a restricted tryptophan environment and deeply buried tryptophans. In the membrane-bound form, the fluorescence of alpha-toxin was quenched by iodide, indicating a conformational change leading to exposure of some tryptophans. A shorter average lifetime of tryptophans in the membrane-bound alpha-toxin as compared to the native toxin supported the conclusions based on iodide quenching of the membrane-bound toxin. Fluorescence quenching of membrane-bound alpha-toxin using brominated and spin-labeled fatty acids showed no quenching of fluorescence using brominated lipids. However, significant quenching was observed using 5- and 12-doxyl stearic acids. An average depth calculation using the parallax method indicated that the doxyl-quenchable tryptophans are located at an average depth of 10 A from the center of the bilayer close to the membrane interface. This was found to be in striking agreement with the recently described structure of the membrane-bound form of alpha-toxin.  (+info)

Cellular mechanisms contributing to response variability of cortical neurons in vivo. (7/2566)

Cortical neurons recorded in vivo exhibit highly variable responses to the repeated presentation of the same stimulus. To further understand the cellular mechanisms underlying this phenomenon, we performed intracellular recordings from neurons in cat striate cortex in vivo and examined the relationships between spontaneous activity and visually evoked responses. Activity was assessed on a trial-by-trial basis by measuring the membrane potential (Vm) fluctuations and spike activity during brief epochs immediately before and after the onset of an evoked response. We found that the response magnitude, expressed as a change in Vm relative to baseline, was linearly correlated with the preceding spontaneous Vm. This correlation was enhanced when the cells were hyperpolarized to reduce the activation of voltage-gated conductances. The output of the cells, expressed as spike counts and latencies, was only moderately correlated with fluctuations in the preceding spontaneous Vm. Spike-triggered averaging of Vm revealed that visually evoked action potentials arise from transient depolarizations having a rise time of approximately 10 msec. Consistent with this, evoked spike count was found to be linearly correlated with the magnitude of Vm fluctuations in the gamma (20-70 Hz) frequency band. We also found that the threshold of visually evoked action potentials varied over a range of approximately 10 mV. Examination of simultaneously recorded intracellular and extracellular activity revealed a correlation between Vm depolarization and spike discharges in adjacent cells. Together these results demonstrate that response variability is attributable largely to coherent fluctuations in cortical activity preceding the onset of a stimulus, but also to variations in action potential threshold and the magnitude of high-frequency fluctuations evoked by the stimulus.  (+info)

Direct evidence of Na+/Ca2+ exchange in squid rhabdomeric membranes. (8/2566)

Na+/Ca2+ exchange has been investigated in squid (Loligo pealei) rhabdomeric membranes. Ca2+-containing vesicles have been prepared from purified rhabdomeric membranes by extrusion through polycarbonate filters of 1-micrometer pore size. After removal of external Ca2+, up to 90% of the entrapped Ca2+ could be specifically released by the addition of Na+; this finding indicates that most of the vesicles contained Na+/Ca2+ exchanger. The Na+-induced Ca2+ efflux had a half-maximum value (K1/2) of approximately 44 mM and a Hill coefficient of approximately 1.7. The maximal Na+-induced Ca2+ efflux was approximately 0.6 nmol Ca2+. s-1. mg protein-1. Similar Na+-induced Ca2+ effluxes were measured if K+ was replaced with Li+ or Cs+. Vesicles loaded with Ca2+ by Na+/Ca2+ exchange also released this Ca2+ by Na+/Ca2+ exchange, suggesting that Na+/Ca2+ exchange operated in both forward and reverse modes. Limited proteolysis by trypsin resulted in a rate of Ca2+ efflux enhanced by approximately fivefold when efflux was activated with 95 mM NaCl. For vesicles subjected to limited proteolysis by trypsin, Na+/Ca2+ exchange was characterized by a K1/2 of approximately 25 mM and a Hill coefficient of 1.6. For these vesicles, the maximal Na+-induced Ca2+ efflux was about twice as great as in control vesicles. We conclude that Na+/Ca2+ exchange proteins localized in rhabdomeric membranes mediate Ca2+ extrusion in squid photoreceptors.  (+info)

A sweep membrane separator includes a membrane that is selectively permeable to a selected gas, the membrane including a retentate side and a permeate side. A mixed gas stream including the selected gas enters the sweep membrane separator and contacts the retentate side of the membrane. At least part of the selected gas separates from the mixed gas stream and passes through the membrane to the permeate side of the membrane. The mixed gas stream, minus the separated gas, exits the sweep membrane separator. A sweep gas at high pressure enters the sweep membrane separator and sweeps the selected gas from the permeate side of the membrane. A mixture of the sweep gas and the selected gas exits the sweep membrane separator at high pressure. The sweep membrane separator thereby separates the selected gas from the gas mixture and pressurizes the selected gas.
Waterproof membrane is a kind of adhesive that is widely used in home and industrial applications due to its high usage. This waterproof membrane has the property that, if a person is fractured or cracked or pierced, it will fix the defects and bind them and do not disturb the function of that object. This waterproof roof membrane manufactured and supplied in various sizes .The waterproof membrane has a very high flexibility, and its prominent features are extremely durable and durable, and can withstand extremely heavy weights . In each house , there should be a number of waterproof membranes to use it when necessary. With a waterproof membrane no longer worry about leaking water pipes and cracking home cabinets, just put a few centimeters of waterproof membrane to it .
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All cells in nature are surrounded by Biological Membranes, which all have the same basic structure. Some organelles found in Eukaryotic Cells also have membranes.
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What does stripping membranes mean - What does stripping your membranes mean? See below. Separating the amniotic sac from the inner wall of the uterus in order to hasen the start of labor.
Dr Qianhong She from the Faculty of Engineering and Information Technologies was recently named a recipient of the 2017 North American Membrane Society (NAMS) Young Membrane Scientist Award.
CSM NF membranes are capable of selectively rejecting divalent ions, making it ideal for a wide range of applications. Typical uses include...
Application of CFD in Membrane Technique Der Fakultät für Ingenieurwissenschaften, Abteilung Maschinenbau der Universität Duisburg-Essen zur Erlangung des akademischen Grades DOKTOR-INGENIEUR genehmigte
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TY - JOUR. T1 - The economics of neurite outgrowth - The addition of new membrane to growing axons. AU - Futerman, Anthony H.. AU - Banker, Gary A.. PY - 1996/4. Y1 - 1996/4. N2 - Recent studies have shown that axonal growth is disrupted by treatments that block the synthesis of membrane components or their delivery by microtubule-based transport. This implies that a continuous supply of newly synthesized membrane components is necessary to sustain growth. In contrast, no clear consensus has yet been achieved about the site of insertion of new membrane components in the membrane of the growing axon, despite the application of new and refined biophysical and molecular techniques to the study of this issue. Until the site of insertion of new membrane components is resolved, little progress can be made in defining the feedback mechanisms by which the supply of new membrane components is co-ordinated with the demands of growth, particularly in cases where the dynamics of neurite growth change from ...
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 ...
Membrane reservoirs serve as membrane buffers that help redistribute membrane area when cells need to stretch or change shape and size. They are found at the cell surface as membrane superstructures varying in size from large membrane folds, to tiny membrane invaginations and caveolae (reviewed in [1]).. Cells are often subject to frequent morphological changes throughout life. For example, cellular processes like phagocytosis and migration require protrusion-driven movement and cell shape changes. At the tissue and organ level, critical biological processes such as respiration and the cardiac cycle rely on the continuous, coordinated expansion and contraction of cells.. In order to accommodate these varied changes in cell morphology, the cell membrane that contains the cell must alter morphology as well. However, cell membranes are highly inelastic. Studies have shown that the maximum elastic stretching of a membrane is only 4%, even when the cell is subjected to lytic tensions which are 100 to ...
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Cell membrane coating technology is an approach to the biomimetic replication of cell membrane properties, and is an active area of ongoing research readily applicable to nanoscale biomedicine. Nanoparticles (NPs) coated with cell membranes offer an opportunity to unite natural cell membrane properties with those of the artificial inner core material. The coated NPs not only increase their biocompatibility but also achieve effective and extended circulation in vivo, allowing for the execution of targeted functions. Although cell membrane-coated NPs offer clear advantages, much work remains before they can be applied in clinical practice. In this review, we first provide a comprehensive overview of the theory of cell membrane coating technology, followed by a summary of the existing preparation and characterization techniques. Next, we focus on the functions and applications of various cell membrane types. In addition, we collate model drugs used in cell membrane coating technology, and review the patent
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?
Dispensing apparatus comprises a housing defining a chamber receiving liquid to be dispensed and comprising a perforate membrane which defines a front wall of the chamber. A vibrating means is connected to the housing and is operable to vibrate the perforate membrane to dispense droplets of liquid through holes in the perforate membrane. The membrane defines an array of holes each of which is flared such that the cross-section narrows in a direction from the rear surface of the membrane in contact with the liquid towards the front surface of the membrane. The apparatus is suitable for dispensing pharmaceutical products as an atomized mist and provides a hand-held inhaler for oral inhalation.
The deformed configurations of an inflated flat nonlinear membrane are obtained by the minimum potential energy principle. The deformed configurations of the membrane are assumed to be represented by a series of geometric admissible functions with unknown coefficients. The unknown coefficients that minimize the total potential energy of the deformed membrane are determined by Fletcher and Powells [1] method. The strain-energy-density function for the numerical calculations is assumed to have the Mooney form. The results for a particular case when the Mooney membrane reduces to the neo-Hookean membrane, agree with the previous results obtained by numerical integration of the corresponding equilibrium equations.. ...
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. ...
WHAT IS EGGSHELL MEMBRANE? Eggs contain a clear film membrane which lines the inside of the shell. Typically, the membrane is discarded along with the shell after extracting the yolk and albumen, but new research confirms that the membrane contains beneficial components for joint support. WHAT DOES EGGSHELL MEMBRANE CO
Orthotropic Membrane for Tall Building Analysis. A method for analyzing tall framed buildings based on the concept of equivalent elastic membrane is presented. The elastic properties of the membrane are evaluated taking into account the effects of finite size joints and axial deformations in the columns. Floors are assumed to be rigid in plane. The equivalent membrane is then analyzed using two-dimensional plane stress, specially orthotropic finite elements. The displacements thus obtained represent directly those of the actual structure, and the member forces are determined by integrating the corresponding stress components in the membrane. Two multistory multibay frames were analyzed, and the results show that a high degree of accuracy can be obtained with significantly smaller number of unknowns than by the exact and other simplified methods. The present technique can be readily applied to the static and dynamic analysis of tubed structures, clad multistory frames, and shear wall and frames
Membranes and Molecular Movement. Animal cell. Plant Cell. Lipid Molecule. Water -loving. Fat-loving. Types of Membranes. Impermeable= Imp ossible to pass. Permeable= Per mission to pass. Semi-permeable= Some can pass. Membrane Proteins. Membrane. Large Molecules. Membrane...
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An electrostatically driven optical membrane comprises a support structure and a membrane structure separated from the support structure by an electrostatic cavity. Stiction plugs are formed in the membrane structure. The plugs extend from a surface of the membrane. In one implementation, the plugs are hollow to allow a subsequent release process in which the sacrificial layer is removed.
Crash Course Biology: In Da Club - Membranes and Transport, by Hank Essential Biology 2.4: Membranes For lots more animations on cell structure and function and cell transport, visit North Harris College. You can also work through the Membranes lessons from HippoCampus Biology. ..........o0O0o.......... Membrane Structure: The Fluid Mosaic Model Fluid Mosaic Model Tutorial from…
Biology Assignment Help, Explain the donnan membrane equilibrium, Explain the Donnan Membrane Equilibrium? If one of the solutions in a two-phase membrane equilibrium contains certain charged solute species that are unable to pass through the membrane, whereas other ions can pass through, the situation is more
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Membranes are barriers which regulate the transformation of information between cells. Biological membranes are inert barriers which plays an important rol..
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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.
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랩원 여러분 먼저 daily paper review를 늦게 올리게 되어 죄송합니다. 랩미팅과 교수님 출장 시 제출할 자료를 작성하느라 daily paper review인지를 잊고 있었습니다. 추후에는 이러한 지연이 다시 발생하지 않도록 노력 하겠습니다. 1. Title & Journal Journal: Journal of Membrane Science, in press, IF: 3.203 Title: A new high-pressure optical membrane module for direct observation of seawa...
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Semantic Scholar extracted view of Ion transport across biological membranes and its control. Workshop organized by the Sonderforschungsbereich 160--Eigenschaften biologischer Membranen--September 25-27 1983, Maria Laach, FRG. by B. Deuticke et al.
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...
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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 ...
Sikalastic RoofPro and RoofCoat membranes are single-component resins, which eliminates the labor costs, inconvenience and potential error involved in mixing multiple components. Single-component technology eliminates incomplete curing and variations in membrane performance that can occur if proper mixing ratios of multiple components are not maintained.. ...
By the end of this section, you will be able to: |ul| |li|Understand the fluid mosaic model of membranes|/li| |li|Describe the functions of phospholipids, proteins, and carbohydrates in membranes|/li| |/ul| (giáo trình - tài liệu - học liệu từ VOER)
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 ...
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
[117 Pages Report] Check for Discount on United States Polymer Separation Membrane Market Report 2017 report by QYResearch Group. In this report, the United States Polymer Separation Membrane market...
I had a membrane sweep done this morning and Ive been leaking small amounts of clear fluid since. Is that my water? Also would love to hear others experiences with membrane sweeps! Getting scheduled to get induced next week if this doesnt work.
Undergrad activated a NS membrane with 100% MeOH... Any hope? - posted in SDS-PAGE and Western Blotting: Hey all, So the undergrad tried to activate a nitrocellulose membrane with 100% MeOH. Is there any hope of getting an actual result with this now? Thanks in advance for your help!
Biological cells are surrounded by a membrane, and here some of the most important processes for sustaining life take place. There can also be something very beautiful happening in membranes, researchers from the University ...
When a standard plant survey isnt getting to the root of the problem, Nalco can offer a membrane autopsy. We use a destructive autopsy procedure to analyze the foulant in the membrane itself. | Ecolab
When a standard plant survey isnt getting to the root of the problem, Nalco can offer a membrane autopsy. We use a destructive autopsy procedure to analyze the foulant in the membrane itself. | Nalco Champion
The Precision Dispensing System for Membranes helped a whey processing plant in the Pacific Northwest improve worker safety, save time, increase productivity, and improve the integrity of their membranes all while saving on cost.
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Synthetic membrane earphone[edit]. Modern technology seeks to minimize or prevent listener fatigue entirely. Blockage of the ... A film of medical-grade polymer (ePTFE) is stretched over a hole, essentially acting as a membrane to help absorb pressure ... Researchers at Asius Technologies have designed a synthetic membrane to take the brunt of the pounding in earphones away from ... the ear drum by disrupting the pressure waves.[18] This new membrane technology can be retrofitted and applied to existing ...
Tympanic membrane displacement[edit]. Tympanic membrane displacement (TMD) technique, proposed nearly twenty years ago by ... away from the tympanic membrane, which tenses the membrane. The stapedius, which emerges from the posterior wall of the ... The sound is transmitted to the stapes, and further through the ossicles, to the tympanic membrane from which it can be ... Later on, ICP can be measured by exerting an external pressure to the tympanic membrane and applying simultaneously the same ...
This membrane is composed of a phospholipid inner membrane, a phospholipid outer membrane, and an intermembrane space. Enclosed ... In its simplest form, this involves the membrane surrounding the cell itself.[20] However, the membrane may be tightly folded ... Embedded in the thylakoid membrane are integral and peripheral membrane protein complexes of the photosynthetic system. ... 3 ions are made from CO2 outside the cell by another carbonic anhydrase and are actively pumped into the cell by a membrane ...
Membranes can be prepared through isolation of the membrane itself, where membranes are cut into squares and immobilized. A ... Membrane exchange chromatography[edit]. A type of ion exchange chromatography, membrane exchange[34][35] is a relatively new ... Brandt, S (1988). "Membrane-based affinity technology for commercial-scale purifications". Bio/Technology. 6 (7): 779-782. doi: ... Membrane Chromatographic[36][37] devices are cheap to mass-produce and disposable unlike other chromatography devices that ...
Membrane filtration. Membrane filters are widely used for filtering both drinking water and sewage. For drinking water, ... Ultrafiltration membranes use polymer membranes with chemically formed microscopic pores that can be used to filter out ... Unless membranes are well-maintained, algae and other life forms can colonize the membranes. ... membrane filters can remove virtually all particles larger than 0.2 μm-including giardia and cryptosporidium. Membrane filters ...
Irritation of mucous membranes[edit]. Hydrogen peroxide is an irritant and cytotoxic. Hydrogen peroxide with concentrations of ... irritation and discolouration of the mucous membranes may occur if a high concentration of oxidising agent comes in to contact ... 10% or higher can cause tissue damage, be corrosive to mucous membranes and cause burning sensation to the skin.[52] Chemical ...
Extracorporeal membrane oxygenation[edit]. Extracorporeal membrane oxygenation (ECMO) is mechanically applied prolonged ... Typical histological presentation involves diffuse alveolar damage and hyaline membrane formation in alveolar walls. Although ... Brogan, TV; Thiagarajan, RR; Rycus, PT; Bartlett, RH; Bratton, SL (December 2009). "Extracorporeal membrane oxygenation in ... Conventional ventilatory support versus Extracorporeal membrane oxygenation for Severe Acute Respiratory failure) trial[25] ...
However, the ability of cross caca membrane is not unidirectional; arginine-based CPPs are able to enter-exit the cell membrane ... which disrupt the membrane enough to allow the fusion protein to cross the membrane. After internalization, the fusion protein ... Mechanisms of membrane translocation[edit]. Cell-penetrating peptides are of different sizes, amino acid sequences, and charges ... Endocytosis is the process of cellular ingestion by which the plasma membrane folds inward to bring substances into the cell. ...
Formation of a glial membrane[edit]. Around the edge of necrosis, astrocytes proliferate. These cells extend processes, and ...
Membrane transport[edit]. Contrary to common belief, thyroid[35] hormones cannot traverse cell membranes in a passive manner ... T1a and T0a are positively charged and do not cross the membrane; they are believed to function via the trace amine-associated ... Despite being lipophilic, T3 and T4 cross the cell membrane via carrier-mediated transport, which is ATP-dependent.[34] ... The Na+/I− symporter transports two sodium ions across the basement membrane of the follicular cells along with an iodide ion. ...
Membrane[edit]. There are a number of proteins that are within the dense granule membrane. To maintain the low pH within the ... Ral has been found within the granule's membrane.[3] There are several adhesive receptors that have luminal binding domains and ... Since dense granules have surface membrane proteins, the activation of CD63 and LAMP-2 can be observed with flow cytometry. ...
Membrane-bound ribosomes[edit]. When a ribosome begins to synthesize proteins that are needed in some organelles, the ribosome ... Bound ribosomes usually produce proteins that are used within the plasma membrane or are expelled from the cell via exocytosis. ... Whether the ribosome exists in a free or membrane-bound state depends on the presence of an ER-targeting signal sequence on the ... Free and membrane-bound ribosomes differ only in their spatial distribution; they are identical in structure. ...
Membranes[edit]. Each capsule consists of two layers or membranes: *an outer (fibrous membrane, fibrous stratum) composed of ... Fibrous membrane[edit]. The fibrous membrane of the joint capsule is attached to the whole circumference of the articular end ... an inner (synovial membrane, synovial stratum) which is a secreting layer. On the inside of the capsule, articular cartilage ... an outer fibrous layer or membrane, and an inner synovial layer or membrane. ...
... the formation of outer membrane vesicles.[8][9] Portions of the outer membrane pinch off, forming spherical structures made of ... Release of outer membrane vesicles. In addition to the use of the multiprotein complexes listed above, Gram-negative bacteria ... The vacuole is formed by the fusion of the cell membrane around the particle. A phagosome is a cellular compartment in which ... It is a simple system, which consists of only three protein subunits: the ABC protein, membrane fusion protein (MFP), and outer ...
Cold applied liquid membranes[edit]. A choice for new roofs and roof refurbishment. This type of a roof membrane is generally ... Protected membrane roof[edit]. A protected membrane roof is a roof where thermal insulation or another material is located ... PVC (vinyl) membrane roofing[edit]. Polyvinyl Chloride (PVC) membrane roofing is also known as vinyl roofing. Vinyl is derived ... Protected membrane roofs are sometimes referred to in the roofing industry as "IRMA" roofs, for "Inverted Roof Membrane ...
Membrane Construction[edit]. In Autumn 2015, Baturina became a strategic investor of Hightex GmbH, a global membrane ... The membranes are typically used in roofs and façades for sporting stadiums and arenas, airport terminals, train stations, ... Hightex will be responsible for the membrane construction of the roof and façade of the Al Bayt Stadium in Qatar. A total of ... In the US, Hightex has been commissioned to install the membrane elements for the "Canopy of Peace" a 50 meter high landmark in ...
A special membrane called dimo (笛膜, lit. "di membrane"), made from an almost tissue-like shaving of reed (made from the inner ... However, the modified dizi's extra tone holes prevent the effective use of the membrane, so this instrument lacks the inherent ... D = Membrane. X = Closed Hole. O = Open Hole. U = Half Open Hole ...
Basement membrane[edit]. Main article: Basement membrane. The epidermis and dermis are separated by a thin sheet of fibers ... The basement membrane controls the traffic of the cells and molecules between the dermis and epidermis but also serves, through ... Iozzo, RV (2005). "Basement membrane proteoglycans: From cellar to ceiling". Nature Reviews Molecular Cell Biology. 6 (8): 646- ... The dermis is tightly connected to the epidermis through a basement membrane and is structurally divided into two areas: a ...
Ligaments and membranes[edit]. The main ligament of the joint is the interosseous talocalcaneal ligament, a thick, strong band ... A synovial membrane lines the capsule of the joint, and the joint is wrapped in a capsule of short fibers that are continuous ...
Membranes[edit]. Polysulfone allows easy manufacturing of membranes, with reproducible properties and controllable size of ... Such membranes can be used in applications like hemodialysis, waste water recovery, food and beverage processing, and gas ... Filter cartridges made from polysulfone membranes offer extremely high flow rates at very low differential pressures when ... "Stability of polyethersulfone membranes to oxidative agents: A review". Polymer Degradation and Stability. doi:10.1016/j. ...
... plasmatic membrane (Pfeffer, 1900),[13] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[14][15] Some ... The cell membrane (also known as the plasma membrane or cytoplasmic membrane, and historically referred to as the plasmalemma) ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ... Within the nuclear membrane, the inner and outer membranes vary in protein composition, and only the outer membrane is ...
Outer chloroplast membrane. Main article: Chloroplast membrane. The outer chloroplast membrane is a semi-porous membrane that ... Inner chloroplast membrane. Main article: Chloroplast membrane. The inner chloroplast membrane borders the stroma and regulates ... All chloroplasts have at least three membrane systems-the outer chloroplast membrane, the inner chloroplast membrane, and the ... Chlorarachniophyte chloroplasts are bounded by four membranes, except near the cell membrane, where the chloroplast membranes ...
Membrane damage[edit]. Damage to the membranes of organelles by monomeric or oligomeric proteins could also contribute to these ... Alpha-synuclein can damage membranes by inducing membrane curvature,[12] and cause extensive tubulation and vesiculation when ... Extensive induction of membrane curvature is deleterious to the cell and would eventually lead to cell death.Apart from tubular ... Research has shown that mutant proteins bind to the CMA-pathway receptors on lysosomal membrane and in doing so block their own ...
Membrane-associated ligases[edit]. Some ligases associate with biological membranes as peripheral membrane proteins or anchored ...
... mainly cell membrane and organelle membranes (especially those of mitochondria), and this is important for maintaining stable ... Garth L. Nicolson (born October 1, 1943)[1] is an American biochemist who made a landmark scientific model for cell membrane, ... With S.J. Singer, Nicolson published a paper titled "The fluid mosaic model of the structure of cell membranes" in 1972,[5] ... Fluid Mosaic Model of cell membrane[edit]. While working as Research Associate at the Salk Institute for Biological Studies, ...
The translocon on the outer chloroplast membrane (TOC)[edit]. The TOC complex, or translocon on the outer chloroplast membrane ... The translocon on the inner chloroplast membrane (TIC)[edit]. The TIC translocon, or translocon on the inner chloroplast ... though many secondary plastids are bounded by an outermost membrane derived from the host's cell membrane, and therefore ... Toc34 is an integral protein in the outer chloroplast membrane that's anchored into it by its hydrophobic[52] C-terminal tail.[ ...
Membrane-introduction mass spectrometry: measuring gases in solution[edit]. Membrane-introduction mass spectrometry combines ... the isotope ratio MS with a reaction chamber/cell separated by a gas-permeable membrane. This method allows the study of gases ... "Studying the oxidation of water to molecular oxygen in photosynthetic and artificial systems by time-resolved membrane-inlet ...
Membranes cell membrane Cell membrane and membrane-bound organelles Subcellular components. All cells, whether prokaryotic or ... The cell membrane, or plasma membrane, is a biological membrane that surrounds the cytoplasm of a cell. In animals, the plasma ... Structures outside the cell membrane. Many cells also have structures which exist wholly or partially outside the cell membrane ... or sometimes a fluid mosaic membrane. Embedded within this membrane is a macromolecular structure called the porosome the ...
... as the cellular plasma membrane and the intracellular membranes of organelles; in animal cells, the plasma membrane physically ... Membranes[edit]. Eukaryotic cells feature the compartmentalized membrane-bound organelles that carry out different biological ... Molecular Computer Simulations - Modeling of Lipid Membranes. *Lipids, Membranes and Vesicle Trafficking - The Virtual Library ... mainly cholesterol in animal cell membranes) are also found in biological membranes.[57] In plants and algae, the ...
cell-adhesion molecules, but no basement membranes except Homoscleromorpha.[16]. inter-cell connections; basement membranes ... cells bound by inter-cell connections and carpet-like basement membranes; muscles; nervous systems; and some have sensory ... and are attached to a fibrous basement membrane, which they secrete. They also secrete the jelly-like mesoglea that separates ...
The membrane also contains membrane proteins, including integral proteins that go across the membrane serving as membrane ... plasmatic membrane (Pfeffer, 1900),[15] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[16][17] Some ... The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the ... Intracellular membranes. The content of the cell, inside the cell membrane, is composed of numerous membrane-bound organelles, ...
Not to be confused with the secondary tympanic membrane of the round window. Eardrum. ... In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, ... The manubrium (Latin: handle) of the malleus is firmly attached to the medial surface of the membrane as far as its center, ... The lateral surface of the membrane is thus concave. The most depressed aspect of this concavity is termed the umbo (Latin: ...
The chloroplast thylakoid membrane is a highly organized, protein-rich, and dynamic membrane system that is the site of the ... Those membrane proteins whose translation terminates before exposure of one of these signals are translated off the membrane ... Lysates are treated with micrococcal nuclease to release ribosomes that are tethered to membranes solely by mRNA. Membrane and ... The establishment of a stable interaction between the nascent peptide and the membrane might be mediated by membrane extrinsic ...
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 ... Intrinsic proteins- Proteins that are tightly embedded in a plasma membrane, and might extend from one side of the membrane to ...
The focus of this research will be on the fabrication of ceramic hybrid membranes. The separation layer of these membranes will ... The master assignment consists of preparing membranes of selected precursors via sol-gel chemistry. The membranes will be ... Relations between process parameters, sol characteristics, membrane structure, and membrane performance will be studied. ... Msc assignment 2d Inorganic Nanosheet membranesMembranes for waste-water treatmentMsc assignment pil grafted membranesIn- ...
Eukaryotic Membranes and Cytoskeleton: Origins and Evolution discusses the evolutionary origin and diversification of ... Eukaryotic Membranes and Cytoskeleton: Origins and Evolution discusses the evolutionary origin and diversification of ...
Porous Ceramic Membranes. Chemically modifying ceramic membranes on the (sub)nanometer scale for separation applications under ... Polymer-functionalized ceramic membranes for solvent nanofiltration. -Zeolitic- or solgel-derived ceramic membranes for gas ... Main interest is focused to the fundamentals of technological applications, such as dense ceramic membranes and the solid oxide ...
... technology and application of membrane operations and related fields, from basic phenomena to the most advanced applications ... membrane distillation, membrane crystallization, membrane stripping, membrane scrubbing). Entries are provided by an ... Enrico Drioli has been working in Membrane Science and Membrane Engineering for many years. He is a Full Professor at the ... Coverage includes membrane reactors and catalytic design (catalytic membrane reactors). Practically all unit operations of ...
Source for information on Premature Rupture of Membranes: Gale Encyclopedia of Medicine, 3rd ed. dictionary. ... Premature Rupture of Membranes Definition Premature rupture of membranes (PROM) is an event that occurs during pregnancy when ... Premature Rupture of Membranes. Definition. Premature rupture of membranes (PROM) is an event that occurs during pregnancy when ... Sometimes the membranes burst before the start of labor, and this is called premature rupture of membranes (PROM). There are ...
PubMed comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.
This second Volume in the series on Membrane Transport in Biology contains a group of essays on transport across single ... biological membranes separating the inside and outside of cells or organelles. W ... Organelle Termination Zellmembran biochemistry biology cell cell membrane chemistry dialysis membrane membrane potential ... Part of the Membrane Transport in Biology book series (MEMBRANE, volume 2) ...
Bottom: membrane tension in the tether inferred from measurements of tether radius (black) and simulated membrane tension in ... B) Simple viscoelastic model of the cell membrane. Springs represent the elastic response of the membrane to stretch, and ... F) Comparison of simulation and experiment for time-dependent membrane tension in a stretched membrane tether and surrounding ... It is widely assumed that membrane flow transmits local changes in membrane tension across the cell in milliseconds, mediating ...
... proton-exchange membranes, (3) hydroxyl ion-exchange membranes, and (4) membrane electrode assemblies. We will include papers ... Membranes have played increasingly important roles in fuel cells. For fuel cells, membranes are involved in fuel processing and ... In fuel processing, CO2- and H2-selective membranes can be used both in membrane reactor configuration to enhance water gas ... Proton-exchange and hydroxyl ion-exchange membranes and membrane electrode assemblies, including cost-effective Nafion ...
The present invention relates to a membrane comprising at least one molecular monolayer composed of low-molecular aromatics and ... cross-linked in the lateral direction, wherein the membrane has a thickn ... Generally, semipermeable membranes are used as membrane filters or as adsorption membranes. A membrane filter is a membrane in ... wherein the membrane has at least 108 openings per mm2 of the surface of the membrane as a perforation. 2. The membrane ...
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The activated membrane can be made of a polysulfone/polyacrolein mixture or a polysulfone microporous membrane treated with a ... The aldehyde functionality on all surfaces provides for effective covalent bonding to the membrane by amine containing ... An activated microporous membrane is provided, having aldehyde functional groups on its inner and outer surfaces. ... membrane. Other embodiments include unsupported membranes. A supported membrane is a membrane cast on a substrate, preferably a ...
"Discovery Links Proteins Necessary To Repair Membranes." Medical News Today. MediLexicon, Intl., 11 Jun. 2009. Web.. 20 Jan. ... His research team announced in December 2008 that it had discovered MG53 as a key initiator of membrane repair in damaged ... Then, through its interaction with Cav3, MG53 recruits intracellular vesicles to the injury site in the membrane, acting as a ... The vesicles interact with dysferlin to fuse with the membrane, thereby creating a repair patch and allowing for normal ...
Ion exchange membrane. It is an ion exchange membrane developed by utilizing the high coating technology cultivated over many ... This membrane separation process results in an enhanced caloric product stream (also known as residue) that is low on CO2, H2S ... Apura™ gas separation membranes include two products: Apura-1.5XF and Apura-2.0C. Such products are designed to maximize the CO ... Apura™ Gas Separation Membrane Element for Fuel Gas Conditioning. With Fujifilms new gas separation element Apura-FG our ...
... Sandra Wardell. Type of Activity:. This is a hands-on activity that simulates cell membrane ... The membrane should self-seal. This can also be used as a metaphor for membrane pores.. *The concept of lateral movement ( ... This activity can either introduce or culminate a unit on cell transport and cell membrane structure.. Required of students:. ... Have the students form an opening in the membrane by floating a circle of thread on the film, popping the inside of it and then ...
Other articles where Semipermeable membrane is discussed: cardiovascular disease: Diseases of the capillaries: The capillaries ... The membrane allows only K+ to diffuse, thereby establishing an electrical potential difference across the membrane. (B) The ... particular size is called a semipermeable membrane. The semipermeable membrane imposes a condition of restricted diffusion in ... on penetration of molecules through semipermeable membranes. Membrane filtration involves simple migration resulting from a ...
The neuronal membrane: …neurons this potential, called the membrane potential, is between −60 and −75 millivolts (mV; or ... thousandths of a volt; the minus sign indicates that the inner surface is negative). When the inside of the plasma membrane has ... Other articles where Membrane potential is discussed: nervous system: ... In nervous system: The neuronal membrane. …neurons this potential, called the membrane potential, is between −60 and −75 ...
Share and Use membrane clipart and images from Openclipart ... Direct Methanol Alkaline Fuel Cell- Anion Exchange Membrane. by ... Direct Methanol Alkaline Fuel Cell Color- Anion Exchange Membrane. by sunblaed. 2011-08-16 ...
... everything you need for studying or teaching Cell membrane. ... Immediately download the Cell membrane summary, chapter-by- ... Membrane Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the ... Membrane Fluidity The membranes of bacteria function to give the bacterium its shape, allow the passage of molecules from the ... Membrane Structure Surrounding each cell within the nervous system is a highly complex lipid bilayer called a membrane formed ...
Membranes. FiberTite temporary roof membrane is resistant to UV rays.. FiberTite® Blue Roof™ Membrane is available in rolls, ... Membranes. New Membranes for Roof System Installation at Temperatures Between 25 to 60 Degrees F. Elastoflex SA V Polar Base is ... Membranes. New SiLyte Features Room temperature Ionic Conductivity up to 1.4 mS/cm. Platform of electrolytic membranes are safe ... Membranes. New Waterproofing Membrane from Elastochem is Applied at High Pressure. Offers durable and flexible formula that is ...
Mais de 60 anos de experiência Aproveite da vasta experiência da Sartorius em controle de qualidade microbiológico para aprimorar o desempenho e melhorar a segurança de seus processos. Obtenha resultados reprodutíveis e confiáveis para testes de lançamento no processo e finais para atender os requisitos de hoje e prever as demandas de amanhã.. ...
Sartorius Membrane filters, a membrane for nearly every need. Our membranes and recommended use(s): ... Cellulose Nitrate (CN) membranes, the One the started it all!. Sartorius Cellulose Nitrate Membrane filters, one for nearly ... Regenerated Cellulose membranes are very low adsorption membranes that are also hydrophilic, solvent-resistant (pH 3-12) and ... Polyethersulfone (PES) membrane filters are hydrophilic, high flow rate and low non-specific protein adsorptive membranes. ...
The assembly of supramolecular structures; membrane structure and function; the cell surface; cytoplasmic membranes; the ... Lipids and Biological Membranes, Carbohydrates. Description not set. Author(s): No creator set. ... Assembly of Proteins in Membranes II from the course General Biochemistry and Molecular Biology. General Biochemistry and ... Assembly of Proteins in Membranes I from the course General Biochemistry and Molecular Biology. General Biochemistry and ...
He and his team have now shed light on how these proteins assemble on the surface of a cell and reshape its membrane. ... frequently form on membranes of cells and are taken up into their interior. The process involves EHD proteins -- a focus of ... not bound to the membrane. Until now, scientists did not know how EHD proteins become activated, attach to the membrane and ... IMAGE: The EHDs present in the cell are in an inhibited state (top left). Once the proteins bind to the membrane, they change ...
This allows a membrane made with graphene to pass water right through it (PDF), while another atom or molecule (even helium)... ... This allows a membrane made with graphene to pass water right through it (PDF), while another atom or molecule (even helium) ... Graphene Membranes Superpermeable to Water 292 Posted by Soulskill on Friday January 27, 2012 @10:12AM. from the it-slices-it- ... These graphene membranes should have truly amazing properties. Armies of physicists will work years to explain such remarkable ...
This novel biosensor employs compounds include a linker lipid for use in attaching a membrane including a plurality of ... The linker lipid comprises within the same molecule a hydrophobic region capable of spanning the membrane, an attachment group ... ionophores to an electrode and providing a space between the membrane and the electrode, the electrode being either in part or ... The present invention relates to a novel biosensor comprising an electrode membrane combination. ...
  • The membrane also contains membrane proteins , including integral proteins that go across the membrane serving as membrane transporters , and peripheral proteins that loosely attach to the outer (peripheral) side of the cell membrane, acting as enzymes shaping the cell. (
  • The instrument could resolve thicknesses that depended on pH measurements and the presence of membrane proteins that ranged from 8.6 to 23.2 nm, with the lower measurements supporting the lipid bilayer hypothesis. (
  • Proteins in the chloroplast thylakoid membrane system are derived from both the nuclear and plastid genomes. (
  • Mechanisms that localize nucleus-encoded proteins to the thylakoid membrane have been studied intensively, but little is known about the analogous issues for plastid-encoded proteins. (
  • This genome-wide, high-resolution analysis of the partitioning of chloroplast ribosomes between membrane and soluble fractions revealed that approximately half of the chloroplast-encoded thylakoid proteins integrate cotranslationally and half integrate posttranslationally. (
  • Chloroplast genomes encode ∼37 proteins that integrate into the thylakoid membrane. (
  • The mechanisms that target these proteins to the membrane are largely unexplored. (
  • The results show that translation invariably initiates off the thylakoid membrane and that ribosomes synthesizing a subset of membrane proteins subsequently become attached to the membrane in a nuclease-resistant fashion. (
  • Membrane proteins whose translation terminates before emergence of a transmembrane segment are translated in the stroma and targeted to the membrane posttranslationally. (
  • In addition, the fractionation behavior of ribosomes in polycistronic transcription units encoding both membrane and soluble proteins adds to the evidence that the removal of upstream ORFs by RNA processing is not typically required for the translation of internal genes in polycistronic chloroplast mRNAs. (
  • The majority of proteins in the thylakoid membrane are subunits of photosynthetic enzyme complexes: photosystem II (PSII), the cytochrome b 6 f complex, photosystem I (PSI), the ATP synthase, and the NADH dehydrogenase-like complex (NDH) ( 2 ). (
  • Whereas the cpTAT pathway operates independently to mediate the translocation of folded proteins across the membrane, the cpSRP, cpSec, and ALB3 machineries cooperate in the targeting and integration of certain substrates. (
  • The bacterial orthologs of cpSRP and ALB3, known as SRP and YidC, respectively, integrate proteins into the cytoplasmic membrane in a cotranslational manner ( 6 , 7 ). (
  • However, the targeting of nucleus-encoded proteins to the thylakoid membrane is posttranslational, as they are synthesized in the cytosol and then imported into the chloroplast stroma before their membrane localization. (
  • In contrast to the sophisticated understanding of mechanisms that localize nucleus-encoded proteins to the thylakoid membrane, little information is available about the analogous issues for plastid-encoded proteins. (
  • Plasma and organelle membranes are composed primarily of lipids (fatty acids, sterols, or other water-insoluble molecules) and proteins (chains of amino acids). (
  • For example, cell membranes of structures predominantly involved in energy production (e.g., the mitochondria) have a higher percentage of proteins, while membranes acting as insulators (e.g., the Schwann cell , which insulates some nerve fibers) have a higher proportion of lipids. (
  • these intrinsic or integral proteins are difficult to remove without destroying the membrane itself. (
  • There are two general types of membrane proteins: transporters and receptors. (
  • A) Illustration of the cell plasma membrane with some transmembrane proteins bound to the underlying cortex. (
  • Springs represent the elastic response of the membrane to stretch, and dampers represent the viscous drag from immobile transmembrane proteins. (
  • C) Dependence of diffusion coefficients for membrane tension (red) and molecular tracers (blue) on the area fraction Φ i of immobile proteins. (
  • Linking these proteins creates a mechanism that allows damaged membranes to be repaired, which may transform treatment for patients who suffer from severe complications of diseases such as muscular dystrophy , as well as cardiovascular disorders and conditions related to advancing age. (
  • Insert coins or other objects (like pencils, Legos) between pins to simulate transmembrane proteins in the membrane model. (
  • Plasma Membrane The plasma membrane is a very thin, continuous sheet of phospholipids and proteins that surrounds all living cells and separates them from their external environment. (
  • Intracellular membrane fusion has been mimicked in vitro using a mix of 17 purified proteins and lipid bilayers. (
  • About half of all biological processes involve membrane proteins, which must be delivered, and eventually removed, with great accuracy to regulate the constancy of structural identity. (
  • 2 describe an enormous technical accomplishment - the self-assembly of 17 individual purified proteins into a fusion 'machine' whose activity and regulation recapitulate those of membrane fusion in an intact cell. (
  • These include the SNARE family of membrane proteins and the Rab proteins, a subfamily of the Ras superfamily of GTPase enzymes. (
  • The membrane-bound SNARE proteins link the two membranes destined for fusion. (
  • They do this by interacting with partner SNARE proteins on the opposing membrane to form a stable, four-coiled bundle consisting of helices from several individual SNARE proteins 4 ( Fig. 1 ). (
  • Figure 1: Proteins work together to mediate endosomal membrane fusion. (
  • SNARE complexes are structurally similar to viral envelope proteins known to catalyse membrane fusion 6 , so a paradigm emerged casting these rod-shaped helical bundles into the central role of 'minimal fusion machine', with all other proteins assigned to supporting roles such as regulation of the SNARE complex 7 . (
  • However, direct tests comparing the contributions of SNAREs alone with SNAREs plus all the other proteins essential for fusion have not been performed because of the complexities of assembling microgram quantities of membrane proteins in defined lipid environments together with other fragile purified proteins - requirements that stretch the limits of current biochemical technologies. (
  • Membranes within cells are composed mainly of lipids and proteins. (
  • Once the proteins bind to the membrane, they change to an active state and build chains that. (
  • He and his team have now shed light on how these proteins assemble on the surface of a cell and reshape its membrane. (
  • These proteins bind themselves to the inside of a cell membrane, where they form long chains and ring-like structures. (
  • Until now, scientists did not know how EHD proteins become activated, attach to the membrane and shape it into tubular structures. (
  • This meeting is for established scientists, post-graduate students and industrial researchers interested in the fundamental questions of cell biology including how peptides and proteins behave within biological membranes. (
  • In the world of membrane proteins, topology defines an important halfway house between the amino-acid sequence and the fully folded three-dimensional structure. (
  • Optimize high-throughput genome-editing methods to tag and label endogenous membrane proteins in the brain (mouse). (
  • Collaborate closely with imaging tool builders at Janelia to develop super-resolution and electron microscopy pipeline to map and annotate the sub-cellular localization of membrane proteins in the brain. (
  • The bilayer closest to the cytoplasm, or the outer mitochondrial membrane ( OMM , not Om Nom Nom ), has integral proteins called porins that allow small molecules to pass freely into the mitochondria. (
  • This family consists of several eukaryotic L6 membrane proteins. (
  • The L6 membrane proteins--a new four-transmembrane superfamily. (
  • UF membranes are used predominantly for the concentration of macromolecules, especially proteins. (
  • In comparison with microfiltration, ultrafiltration membranes are notably used to reject viruses, in addition to macromolecules and proteins. (
  • It is proposed that these rafts function as platforms for the attachment of proteins when membranes are moved around inside the cell and during signal transduction. (
  • Using cryo-electron tomography, we discovered that the cisterna membranes are held together by linker proteins," explains Benjamin Engel, first author of the study. (
  • After being produced at the endoplasmic reticulum, proteins enter the Golgi apparatus and travel through its stacks of cisterna membranes. (
  • The elaborate membrane architecture of the Golgi is crucial for regulating the modification and sorting of cargo proteins, as different Golgi enzymes are localized to specific cisterna stacks. (
  • By using cryo-electron tomography to look at the Golgi apparatus, Benjamin Engel and his colleagues discovered arrays of proteins between the cisterna membranes (see figure), which had gone unseen using other techniques. (
  • 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. (
  • Eukaryotic Membranes and Cytoskeleton: Origins and Evolution discusses the evolutionary origin and diversification of eukaryotic endomembranes and cytoskeleton from a cell biological and comparative genomic perspective. (
  • Lidietta Giorno is a membrane biotechnologist with a strong background in biological science, chemical technologies and new materials. (
  • This second Volume in the series on Membrane Transport in Biology contains a group of essays on transport across single biological membranes separating the inside and outside of cells or organelles. (
  • As a result of investigations in many laboratories over the past four decades, our picture of the water permea- bility of the red cell membranes is rather detailed when compared to the water permeability of other biological membranes. (
  • The organization and regulation of membrane-fusion reactions, then, are crucial for virtually every membrane-bound biological process. (
  • The primary objective of this experiment is to determine the stress that various factors, such as osmotic balance, detergents, and pH, have on biological membranes. (
  • You will test the effect of osmotic balance, detergents, and pH changes on biological membranes. (
  • Determine the effect of osmotic balance on biological membranes. (
  • Lipid bilayer membranes (also known as black lipid membranes--BLM's ) are well known in the biological and chemical fields. (
  • Combinations of atomistic and coarse-grain (eg Martini) modelling approaches offer detailed structural and thermodynamic representations of the properties of membranes that are likely to approach the complexity of biological lipid assemblies relatively soon. (
  • Intracellular membranes provide additional surface area for key biological processes. (
  • Fetal membranes have been used as biological bandages for skin grafts as well as for serious burns. (
  • In these volumes we hope to provide a readily available comprehensive source of critical information covering many of the exciting, recent developments on the structure, biosyn- thesis, and function of biological membranes in microorganisms, animal cells, and plants. (
  • Because this book is presented in a compact, understandable format, readers can start from biological cell membranes, then net aspects of host-guest chemistry for effective recognition of ions and molecules, followed by its application for artificial sensors-such as neuro-systems, functionalized new detergents, mechanochemical systems, and separation chemistry. (
  • Proceedings of an International Symposium on Biological and Synthetic Membranes, held at Lexington, Kentucky, October 12-14, 1988", organized by the Center of Membrane Sciences, University of Kentucky. (
  • Mobile membranes represent a variant of membrane systems inspired by the biological movements given by endocytosis and exocytosis. (
  • Membrane most commonly means a thin, selective barrier, but it is sometimes used for films that function as separators, like biological membranes. (
  • Premature rupture of membranes (PROM) is an event that occurs during pregnancy when the sac containing the developing baby (fetus) and the amniotic fluid bursts or develops a hole prior to the start of labor. (
  • Sometimes the membranes burst before the start of labor, and this is called premature rupture of membranes (PROM). (
  • When the water breaks early, it is called premature rupture of membranes (PROM). (
  • If the water breaks before the 37th week of pregnancy, it is called preterm premature rupture of membranes (PPROM). (
  • Preterm premature rupture of membranes at 22-25 weeks' gestation: perinatal and 2-year outcomes within a national population-based study (EPIPAGE-2) Most clinical guidelines state that with early preterm premature rupture of membranes , obstetric and pediatric teams must share a realistic and individualized appraisal of neonatal outcomes with parents and consider their wishes for all decisions. (
  • of membranes , to adequately counsel parents during pregnancy and to reflect on our policies of care at these extreme gestational ages.We sought to describe both perinatal and 2-year outcomes of preterm infants born after preterm premature rupture of membranes at 22-25 weeks' gestation.EPIPAGE-2 is a French national prospective population-based cohort of preterm infants born in 546 maternity units in 2011. (
  • Do preoperative chronic hypertension, preterm premature rupture of membranes , chorioamnionitis, and placental abruption provide warning to this rare occurrence? (
  • [9] In 1895, Ernest Overton proposed that cell membranes were made of lipids. (
  • A membrane is actually two layers of lipids that form a shell around the cell. (
  • Thus the membrane forms a stable yet flexible configuration with a certain amount of fluidity: individual phospholipids can move rapidly across the surface of the membrane, and part to allow molecules soluble in organic media (e.g., other lipids, dissolved gases, etc.) to enter the cell. (
  • Cells produce an array of lipids using tightly controlled enzymes to ensure proper physical properties of membranes. (
  • 1. Functional roles of lipids in membranes (W. Dowhan, M. Bogdanov). (
  • It is intended as an advanced and up-to-date textbook for teachers and students who are familiar with the basic concepts of lipid biochemistry and will also serve as a general reference book for scientists studying lipids, lipoproteins and membranes. (
  • [4] In addition, cell membranes are involved in a variety of cellular processes such as cell adhesion , ion conductivity and cell signalling and serve as the attachment surface for several extracellular structures, including the cell wall , the carbohydrate layer called the glycocalyx , and the intracellular network of protein fibers called the cytoskeleton . (
  • In 1890, an update to the Cell Theory stated that cell membranes existed, but were merely secondary structures. (
  • We have not attempted to include material on all types of plasma and intracellular membranes, but rather have emphasized structures which have been studied relatively thoroughly. (
  • Comparing the active and inactive protein structures, they discovered that EHD molecules flip open when they bind to the membrane, exposing specialized regions. (
  • Next-generation synthetic biology goals will require a clearer understanding of how to control reticulated membrane structures in order to fabricate the supramolecular structures necessary for advanced synthesis and behaviour. (
  • With recent advances in computational modelling, it is now feasible to model membranes that can deliver realistic representations of multi-lipid assemblies and the interactions of peptides with these structures with atomistic detail seems also within reach. (
  • Although the concept of membrane-protein topology dates back at least 30 years, recent advances in the field of translocon-mediated membrane-protein assembly, proteome-wide studies of membrane-protein topology and an exponentially growing number of high-resolution membrane-protein structures have given us a deeper understanding of how topology is determined and of how it evolves. (
  • This membrane is folded and twisted throughout the mitochondrion into structures called cristae , much like all 25 feet of your small intestine is twisted and folded throughout your abdomen. (
  • Due to an intrinsic property of electrospinning, nanofibers are often deposited to form 2D membranes or sheets with dense structures and small pore sizes that are less than the size of cells. (
  • Although 3D printing technology is not quite well enough developed to yet produce large scale membranes that will be cost competitive with existing products, this work does signal what the future possibilities are with 3D printing, to produce membranes beyond that which are currently available, including controlled complex pore structures, integrated surface patterns and membranes based on nature. (
  • These membranes serve as linings and covering for various body structures, and they also form glands. (
  • The connective tissue layer houses nerves and blood vessels that supply the upper layers, and it also binds the membrane to the bodily structures. (
  • handle ) of the malleus is firmly attached to the medial surface of the membrane as far as its center, drawing it toward the tympanic cavity . (
  • The lateral surface of the membrane is thus concave. (
  • during or after at least one of the above-mentioned steps (c) and (d), the step of: (e) perforating the membrane, which is performed such that openings having a diameter in the range from 0.1 nm to 1 μm are produced, wherein the membrane has at least 10 8 openings per mm 2 of the surface of the membrane as a perforation. (
  • Two essays concern the excitable membranes of nerve and muscle cells while the remaining four chapters treat transport across several types of intracellular membranes. (
  • The distinct behavior of ribosomes synthesizing the inner envelope protein CemA indicates that sorting signals for the thylakoid and envelope membranes are distinguished cotranslationally. (
  • The chloroplast thylakoid membrane is a highly organized, protein-rich, and dynamic membrane system that is the site of the light reactions of photosynthesis ( 1 ). (
  • polyaldehyde having physically bound aldehyde functional groups which are thus bound without significant chemical reaction to substantially all said available surface areas, said polyaldehyde further having unbound aldehyde groups that are free to react with an have an affinity for aldehyde reactive materials, said unbound polyaldehyde groups being in an amount such that the affinity of the membrane for protein is characterized by enhanced specifity and total binding capacity. (
  • His research team announced in December 2008 that it had discovered MG53 as a key initiator of membrane repair in damaged tissue, making it the first group to specifically pinpoint a protein responsible for promoting cell repair. (
  • The concept of lateral movement (lateral diffusion) of transmembrane protein complexes can be shown by having students insert a pencil or other object through the membrane and move it around. (
  • A common companion for blotting paper is nitrocellulose membranes, often used for protein and DNA analysis and purifications. (
  • 200 μg/cm2) Sartorius' nitrocellulose membranes are ideal for western blotting, DNA blotting as well as dot or slot blots, and they have been optimized for superior performance in all protein blotting systems, including electrotransfer, semi-dry or simple capillary blotting applications. (
  • Polyethersulfone (PES) membrane filters are hydrophilic, high flow rate and low non-specific protein adsorptive membranes. (
  • As the electrons move from one membrane protein to the next, energy is released and protons (hydrogen ions, or H + ) in the matrix are pumped across the IMM and into the intermembrane space. (
  • This term is used when it is not known if the protein is found in or associated with the inner or outer nuclear membrane. (
  • Mitochondrial membrane protein-associated neurodegeneration (MPAN) is a disorder of the nervous system. (
  • Dogu O, Krebs CE, Kaleagasi H, Demirtas Z, Oksuz N, Walker RH, Paisán-Ruiz C. Rapid disease progression in adult-onset mitochondrial membrane protein-associated neurodegeneration. (
  • Hartig M, Prokisch H, Meitinger T, Klopstock T. Mitochondrial membrane protein-associated neurodegeneration (MPAN). (
  • This protocol describes how to strip the antibodies from a PVDF membrane so that another protein can be assessed on the same blot. (
  • The image shows the 3D molecular structure of a membrane-linking protein array (color), extracted from a cryo-tomogram of the native Golgi (greyscale). (
  • The way the protein arrays hold two Golgi membranes together is similar to how a zipper works when you put on a jacket", explains PhD student Shoh Asano, co-author of the study. (
  • Molecular Separation by using membranes has proven to be one of the most energy efficient routes to separate gases and liquids on nano scale. (
  • The present invention relates to a membrane comprising at least one molecular monolayer composed of low-molecular aromatics and cross-linked in the lateral direction, wherein the membrane has a thickness in the range from 1 to 200 nm and a perforation in the form of openings having a diameter in the range from 0.1 nm to 1 μm, to a method for the production thereof, and to a use thereof. (
  • 2. The membrane according to claim 1, which is composed of a stack of at least two molecular monolayers arranged one on top of the other. (
  • 3. The membrane according to claim 1, wherein one of the two surfaces of at least one molecular monolayer is modified by functional groups. (
  • Together with international colleagues, Daumke and his PhD student Arthur Alves de Melo have now published an article in the current issue of the scientific journal PNAS that describes the active form of this molecular EHD machine - that which occurs when it comes into contact with the membrane. (
  • Another region reorients toward the membrane and anchors the molecular machines on the cell surface. (
  • The molecular questions that require clarification and their solutions bridge the many divides between the fundamental physical chemistry of macromolecular polyelectrolytes and the supramolecular chemistry of membrane assemblies related to cell biology as well as drug development and synthetic biology. (
  • This session will address the simplest membrane and peptide interactions in order to build a clear picture of the limiting molecular properties of the respective interactions as well as defining some of the outstanding questions that need to be considered in more sophisticated systems. (
  • It is an animation that is put together very well and provides a nice visualization of molecular components found in the cell membrane. (
  • They have the solubility, purity and range of molecular weight needed to make hollow fiber, flat sheet and tubular membranes with the pore size and separation selectivity you need. (
  • 6. The membrane of claim 1 in which the poly(ethylene oxide) substituent has an average molecular weight of from about 200 to about 2000. (
  • The present invention provides modified molecular sieve membranes with improved CO 2 /CH 4 separation selectivity and methods for making such membranes. (
  • The molecular sieve membranes are modified by adsorption of a modifying agent, such as ammonia, within and/or on the membrane. (
  • 12. The method of claim 1 wherein the membrane is a small pore molecular sieve membrane. (
  • 15. The method of claim 1, wherein the molecular sieve membrane comprises Brønsted acid sites. (
  • Synder offers an extensive and growing range of spiral-wound Ultrafiltration (UF) membrane Molecular Weight Cut-Offs. (
  • Synder Filtration's extensive line of polymeric Ultrafiltration membranes have a molecular weight cutoff (MWCO) ranging from 1kD-500kD. (
  • The NFX, NFW, & NFG membranes encompass molecular weight cutoffs (MWCO) from 150-800Da and have typically displayed better rejection and greater flux than the leading competitor. (
  • Drews G and Golecki JR (1995) Structure, molecular organization, and biosynthesis of membranes by purple bacteria. (
  • This interesting work extensively describes newer applications of liquid membrane systems which contain molecular and/or ion recognizing carrier compounds and the related characteristic membrane materials. (
  • Membrane technology potentially offers lower energy, more sustainable molecular separations that can be applied to a wide range of gas and liquid separations. (
  • Although some lipid-soluble molecules can permeate the cell membrane, many of the nutrients that a cell needs to function are too large to readily enter the cell. (
  • Examples of transporters are channels, which facilitate free movement of molecules across the membranes, and pumps, which require a certain amount of energy in order to transport molecules. (
  • While lipid-soluble molecules can pass readily through the membrane, water-soluble and larger particles require another mode of entry. (
  • Only lipid-soluble molecules and some small particles (e.g., biologically important gases such as oxygen and nitrogen) can readily permeate the cell membrane. (
  • Passive transport or facilitated diffusion occurs when water-soluble molecules and ions move through the membrane with the help of transporters (also called permeases). (
  • Four chapters describe transport of different types of molecules and ions across the plasma membranes of mammalian red cells. (
  • The membrane allows passage of small solution components (usually the solvent) while preventing passage of larger molecules. (
  • on penetration of molecules through semipermeable membrane s. (
  • Membrane Structure Surrounding each cell within the nervous system is a highly complex lipid bilayer called a membrane formed by microscopic phospholipid molecules. (
  • Membrane Fluidity The membranes of bacteria function to give the bacterium its shape, allow the passage of molecules from the outside in and from the inside out, and to prevent the internal contents f. (
  • Modulation of the ion flux of the membrane in response to specific molecules is also known, especially in the biochemical fields. (
  • These molecules do not get very far, though, because they soon encounter the second bilayer , or inner mitochondrial membrane (IMM) . (
  • The channels formed when the organic support is destroyed provide the ability to withdraw small catalytic products or size-separated molecules from the metal oxide membrane. (
  • As illustrated below, through the application of pressure to concentrated solutions, water molecules can be driven through a membrane against natural osmotic pressure. (
  • This membrane separates these water molecules from all dissolved solids and other contaminants, thus producing ultrapure water. (
  • Membranes are a semi-permeable selective barrier that separate the molecules in a mixture within a gas or liquid into two streams, a key example of this being the separation of salt from water for desalination using reverse osmosis membranes. (
  • Apura™ gas separation membranes include two products: Apura-1.5XF and Apura-2.0C. Such products are designed to maximize the CO 2 removal capacity and hydrocarbon recovery and can be combined in stages to be able to maximize the overall separation efficiency. (
  • Today's gas separation membranes are made using sulfone polymers as well as fluoropolymers. (
  • Hyflon® AD amorphous perfluoropolymers are suitable for polymeric gas separation membranes used in the separation of gases or vapors, the recovery of gases and the enrichment of air in pharmaceutical or chemical processing applications. (
  • Director of the Centre for Advanced Separations Engineering at the University of Bath, Dr Darrell Patterson, commented: "This review is the first to explore the possibility and challenges of using 3D printing for producing separation membranes. (
  • 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. (
  • Membrane Cell membranes or plasma membranes surround cells, separating the cytoplasm and organelles on the inside from the extracellular fluid on the outside. (
  • Abstract Objective To review the evidence and provide recommendations on the use of antibiotics in preterm premature rupture of the membranes (PPROM). (
  • It was not until later studies with osmosis and permeability that cell membranes gained more recognition. (
  • In Chapter 1, R. I. Macey describes this picture and also considers the permeability of red cell membranes to non- electrolytes, including metabolic substrates such as sugars, amino acids, purines and nucleosides. (
  • Barrier membranes designed for GBR/GTR have to meet the following criteria: host tissue integration, biocompatibility, cell occlusiveness, permeability for nutrients and ease of use 1 . (
  • This fluid, along with the fetus and the placenta, is enclosed within a sac called the amniotic membrane. (
  • The amniotic membrane contains the amniotic fluid and protects the fetal environment from the outside world. (
  • In the most common sequence of events (about 90% of all deliveries), the amniotic membrane breaks (ruptures) around this time. (
  • In some cases of preterm PROM, it is believed that bacterial infection of the amniotic membrane causes it to weaken and then break. (
  • Amnionitis is an infection of the amniotic membrane. (
  • This membrane is called the amniotic sac. (
  • It involves your doctor sweeping their (gloved) finger between the thin membranes of the amniotic sac in your uterus. (
  • A new review looks at the potential of fetal membranes, which make up the amniotic sac surrounding the fetus during pregnancy, for regenerative medicine. (
  • The two chorioamniotic membranes are the amnion and the chorion, which make up the amniotic sac that surrounds and protects the fetus. (
  • This work is part of the University's Centre for Advanced Separations Engineering (CASE) and is the first time the properties of different 3D printing techniques available to membrane fabrication have been assessed. (
  • Led by Yushan Yan, Distinguished Professor of Engineering, the research at UD will focus on creating a series of polymer-based hydroxide exchange membranes (HEMs). (
  • Our goal is to develop a process to easily synthesize the polymer at scale, creating large area membranes for testing that are thinner than human hair. (
  • Platform of electrolytic membranes are safe, high-performance and mechanically-strong polymer electrolyte. (
  • Cyclical operation, various impurities in the gas flow, and changing application conditions can all stress the materials used in high-temperature polymer electrolyte membrane (PEM) fuel cells and electrochemical hydrogen separation systems. (
  • 2. The membrane of claim 1, wherein the polymer is a polysulfone. (
  • 7. filter unit, comprising the polymer membrane of claim 1. (
  • 14. A filter unit, comprising the polymer membrane of claim 8. (
  • This book's inter-disciplinary approach for theoreticians and experimentalists for future cross-fertilization of understanding and developments in the areas of membranes including polymer technology and green chemistry applications. (
  • [1] [2] The cell membrane consists of a lipid bilayer , including cholesterols (a lipid component) that sit between phospholipids to maintain their fluidity at various temperatures. (
  • The lipid bilayer hypothesis, proposed in 1925 by Gorter and Grendel, [11] created speculation to the description of the cell membrane bilayer structure based on crystallographic studies and soap bubble observations. (
  • The lipid bilayer membranes are however extremely fragile and sensitive to non-specific physical and chemical interference. (
  • A semipermeable membrane is a selective barrier, and many such barriers are found in plants and animals. (
  • The properties are so unusual that it is hard to imagine that they cannot find some use in the design of filtration, separation or barrier membranes and for selective removal of water,' said one of the researchers. (
  • The present invention relates to electrode membrane combinations for use in ion selective electrodes and biosensors. (
  • in BLM's and that the selective ion flux through the membrane could thus be monitored. (
  • Synthetic Strategies for Selective Liquid Membranes. (
  • This delivery and removal is mediated by the membrane-bound organelles of eukaryotic cells, which communicate with each other by budding off vesicles and other transport packages, which travel to, and fuse with, target membranes. (
  • Eukaryotic cells are delimited by a membrane that separates the inside from the outside, and they also contain many membrane-defined subcellular compartments. (
  • 2. An activated polymeric microporous membrane as recited in claim 1 wherein the pore surfaces have free aldehyde functionalities available for affinity reaction. (
  • Highly asymmetric polymeric membranes with large pores which yield bubble points in the range of 0.5 to 25 psid and superior flow characteristics. (
  • In the anatomy of humans and various other tetrapods , the eardrum , also called the tympanic membrane or myringa , is a thin, cone-shaped membrane that separates the external ear from the middle ear . (
  • 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. (
  • Depending on the type of epidermolysis bullosa, blistering may occur in the top layer of skin (epidermis), the bottom layer (dermis) or the layer that separates the two (basement membrane zone). (
  • [3] The cell membrane controls the movement of substances in and out of cells and organelles. (
  • While Robert Hooke 's discovery of cells in 1665 led to the proposal of the Cell Theory , Hooke misled the cell membrane theory that all cells contained a hard cell wall since only plant cells could be observed at the time. (
  • However, some microscopists correctly identified at this time that while invisible, it could be inferred that cell membranes existed in animal cells due to intracellular movement of components internally but not externally and that membranes were not the equivalent of a cell wall to plant cell. (
  • It was also inferred that cell membranes were not vital components to all cells. (
  • Paul Andersen explains how cells are selectively permeable with the help of their cell membrane. (
  • This membrane work is a critical part of a larger overall effort at UD to make platinum-free fuel cells a commercial reality for zero-emission cars. (
  • Here, we show that propagation of membrane tension occurs quickly in cell-attached blebs but is largely suppressed in intact cells. (
  • In primary endothelial cells, local increases in membrane tension lead only to local activation of mechanosensitive ion channels and to local vesicle fusion. (
  • Membrane Mechanics in Living Cells. (
  • Propagation of membrane tension in cells. (
  • Membranes have played increasingly important roles in fuel cells. (
  • For fuel cells, membranes are involved in fuel processing and as proton-exchange and hydroxyl ion-exchange materials in membrane electrode assemblies. (
  • Proton-exchange and hydroxyl ion-exchange membranes and membrane electrode assemblies, including cost-effective Nafion replacements particularly for 120 - 180oC and new membranes for alkaline fuel cells, are critical to the widespread use of fuel cells. (
  • Small "bubbles" frequently form on membranes of cells and are taken up into their interior. (
  • This greatly inhibits the applications of electrospun nanofibers, because cells fail to seed or penetrate throughout the nanofiber membranes, which is undesirable," he explained. (
  • The fetal membranes have been used successfully in medical applications for over a century, but we continue to discover new properties of these membranes," said Dr. Rebecca Lim, author of the STEM CELLS Translational Medicine review. (
  • Membrane computing (also called P systems) is a branch of natural computing introduced by Pǎun in 1998 which abstracts computing models from the architecture and the functioning of living cells [ 1 ]. (
  • The outer portion of epithelial membranes - epithelial tissue - may be composed of a single layer of cells known as simple epithelium . (
  • Pathophysiology of the fetal membranes, such as microfractures, senescence of cells in the fetal membrane and inflammation can lead to an increased chance of preterm premature rupture of the fetal membranes (pPROM). (
  • Membrane systems have been inspired from the structure and the functioning of the living cells. (
  • With high rejections of hardness, metals, and organic matter, and lower operating pressures than reverse osmosis membranes (0.3-4.0MPa), Synder's NF membranes and systems are the economical option in certain water treatment applications. (
  • Extracorporeal membrane oxygenation (ECMO) is when a specially trained medical team uses a machine to do the work that the heart and lungs normally do. (
  • Extracorporeal membrane oxygenation (ECMO) is a specialized type of life support for the heart and lungs. (
  • Extracorporeal membrane oxygenation (ECMO) is a specialized type of life support that can provide circulation and oxygenation when the heart and lungs are not working. (
  • Although the presence of thylakoids, intracellular cytoplasmic membranes and chlorosomes can indicate photosystem, they are not useful as a taxonomic trait. (
  • It can be used in advanced biology classes as an introduction to phospholipid bilayers and detailed work relating to cell membrane structure. (
  • Discuss the structure of cell membranes and phospholipid bilayers. (
  • In the compartments defined by membranes there are objects that can evolve to other objects and pass through the membranes. (
  • It consists of flat membrane-enclosed compartments (called cisternae) that are densely packed on top of each other, like a stack of pancakes. (
  • The cellulose nitrate membranes are available in different pore sizes from 0.2 μm to 8 μm. (
  • Available in pore sizes from 0.1 um to 0.45 um and multiple diameters, Sartorius is sure to have a polyethersulfone (PES) membrane filters for nearly your every need. (
  • Microfiltration (MF) membranes feature the largest pore sizes of Synder's membrane product line, ranging from 800kDa to 0.2µ. (
  • Just as skin lines and protects the outside of the body, mucous membranes line and protect the inside of your body. (
  • You can find mucous membranes inside of your nose , mouth, lungs, and many other parts of the body. (
  • Mucous membranes make mucus, which keeps them moist. (
  • Two primary types of epithelial membranes exist: serous membranes and mucous membranes. (
  • Mucous membranes, also called mucosae, are one major type of epithelial membrane. (
  • These tiny hairs guard the mucous membranes by grabbing onto particles of dust or other foreign matter. (
  • In a process called glycolysis , which occurs in the cytoplasm just outside the mitochondrion, electrons are stripped from glucose and passed through the outer mitochondrial membrane into the intermembrane space . (
  • The mitochondrial membrane is the site of ATP synthesis, and the ATP made is inside the mitochondrion. (
  • The stem cell populations arising from the fetal membranes are plentiful and diverse, while the membrane itself serves as a unique biocompatible scaffold for bioengineering applications. (
  • The fetal membranes are membranes associated with the developing fetus. (
  • The other fetal membranes are the allantois and the secondary umbilical vesicle. (
  • The fetal membranes surround the developing embryo and form the fetal-maternal interface. (
  • The fetal membranes are derived from the embryoblast layer (inner cell mass) of the implanting blastocyst. (
  • The trophoblast layer differentiates into amnion and the chorion, which then comprise the fetal membranes. (
  • From inside to outside, the fetal membranes consist of amnion and chorion. (
  • The chorionic membrane is a fibrous tissue layer containing the fetal blood vessels. (
  • The fetal membrane surrounds the fetus during the gestational period and ensures maintenance of pregnancy to delivery, protection of the fetus as well as being critical in maintaining the conditions necessary for fetal health. (
  • The fetal membranes separate maternal tissue from fetal tissue at a basic mechanical level. (
  • The fetal membrane is composed of a thick cellular chorion covering a thin amnion composed of dense collagen fibrils. (
  • At the end of gestation, a 'weak zone' develops in the fetal membrane overlying the cervix due to collage remodelling. (
  • This eventually leads to rupture of the fetal membrane and the onset of labour. (
  • citation needed] As pregnancy advances to term, the fetal membranes undergo weakening. (
  • Throughout gestation the fetal membranes undergo remodelling to allow for the increase in size of the uterus. (
  • A top layer of epithelial tissue is joined to underlying connective tissue by a basement membrane . (
  • This amnionic epithelium is connected to a basement membrane, which is then attached by filaments to a connective tissue layer. (
  • Permeation occurs when a substance moves through the membrane from a region of high concentration to a region of low concentration, a process called diffusion. (
  • The membranes will be tested for their gas permeation and separation capacities. (
  • For example, retention by microfiltration membranes is accomplished mainly through mechanical sieving. (
  • Technologies range from reverse osmosis (RO) to microfiltration (MF) for symmetric and asymmetric membranes. (
  • Synder's microfiltration membranes are commonly used as pretreatment or clarification step to ultrafiltration and nanofiltration processes, but can also be used to fractionate large macromolecules from smaller ones, such as casein/ whey fractionation in the dairy industry. (
  • Independently, the leptoscope was invented in order to measure very thin membranes by comparing the intensity of light reflected from a sample to the intensity of a membrane standard of known thickness. (
  • Charged vs. uncharged nylon membranes? (
  • The protocol I'm looking at specifies uncharged nylon membranes, but the Amersham literature says that their Hybond N+ is the best membrane for RNA blotting (positively charged nylon). (
  • The problems of approximate, and exact, controllability of the transient behavior of a system of interconnected, two-dimensional elastic membranes in three dimensional space are considered. (
  • Optimal reinforcing networks for elastic membranes. (
  • The project, "Highly Conductive, Stable and Robust Hydroxide Exchange Membranes Based on Poly (Aryl Piperidinium)," is one of 16 funded through the $37 million program, which is aimed at transforming energy storage and conversion. (
  • Original and review papers on membranes for fuel cell applications are sought, including (1) fuel processing, (2) proton-exchange membranes, (3) hydroxyl ion-exchange membranes, and (4) membrane electrode assemblies. (
  • Fujifilm utilizes multilayer composite membranes, which makes the modules extremely robust towards aromatics and water. (
  • This is where Celtec ® membrane electrode assemblies (MEAs) show their strength. (
  • Membrane filtration involves simple migration resulting from a concentration difference on the two sides of the membrane. (
  • He worked on membrane systems in citrus plants, sugar mills, and electrocoat paint plants that use tangential flow filtration. (
  • Nanoporous membranes engineered to mimic natural filtration systems can be used in smart implantable drug delivery systems, bioartificial organs, and other novel nano-enabled medical devices. (
  • Later in the 1930s, the membrane structure model developed in general agreement to be the paucimolecular model of Davson and Danielli (1935). (
  • Relations between process parameters, sol characteristics, membrane structure, and membrane performance will be studied. (
  • You just viewed Membranes and Cell Structure . (
  • This is a hands-on activity that simulates cell membrane structure and function. (
  • If working with middle school students, the details of the membrane structure need not be explored in as much depth. (
  • What is the structure of the cell membrane and what unique properties does it have? (
  • What ordinary substances can be used to model the structure and functioning of the cell membrane? (
  • This activity can either introduce or culminate a unit on cell transport and cell membrane structure. (
  • Previous class discussions on cell membrane structure (this can vary), 50 minutes for the activity, 20 minutes for follow-up discussion and questions. (
  • Students can explore for themselves how a cell membrane might work and how its structure is related to function. (
  • In an earlier study, he and his team analyzed the three-dimensional structure of EHDs in an inactive form - i.e. not bound to the membrane. (
  • This site includes an animated presentation of the cell membrane that walks users through the structure and function of individual components. (
  • The ability of a mitochondrion to convert glucose and ADP , adenosine diphosphate, into ATP is intricately connected to the structure of the mitochondrial membranes. (
  • The article, "Fast transformation of 2D nanofiber membranes into pre-molded 3D scaffolds with biomimetic and oriented porous structure for biomedical applications," is authored by Sixuan Chen, Johnson V. John, Alec McCarthy, Mark A. Carlson, Xiaowei Li and Jingwei Xie. (
  • 9. The method of claim 1, wherein the membrane has a MFI or MEL structure. (
  • A new aspect of cell membrane structure is presented, based on the dynamic clustering of sphingolipids and cholesterol to form rafts that move within the fluid bilayer. (
  • This article describes the occurrence, structure, arrangement and function of bacterial intracytoplasmic membranes (ICMS) including magnetosomes of magnetotactic bacteria, the thylakoids of cyanobacteria and chloroxybacteria, the ICMS of purple bacteria and chemoautotrophic bacteria, the chlorosomes of green bacteria and the anammoxosome of ammonia‐oxidising bacteria. (
  • No. 4,037,061 disclose rigidly affixing a loudspeaker membrane to a supporting structure. (
  • In this paper, we propose a method of fraction reduction and discuss how to carry it out in cell-like P systems with the membrane structure and the rules with priority designed. (
  • The introductions of the complexity, parallelism, decomposition of membrane, and hierarchical structure can be found in [ 8 , 9 ]. (
  • And, in [ 12 ], the membrane structure is simplified greatly and efficiency of the computations is also improved owing to arithmetic operations being performed in a single membrane without priority rules. (
  • In Section 4 , based on cell-like P system, the rules for implementing fraction reduction are described in detail with the membrane structure designed. (
  • Due to its natural comb-like and multi-layered collagen structure (with an increased content of collagen type III), the botiss Jason® membrane shows a slow degradation, making it the recommended choice in our portfolio particularly for large augmentative procedures. (
  • The unique processing, as well as the open porous/3-dimensional collagen structure of this membrane, are the basis for its application in dental bone and tissue regeneration. (
  • The structure of epithelial membranes is basic. (
  • The model is characterized by two essential features: A spatial structure consisting of a hierarchy of membranes (which do not intersect) with objects associated to them. (
  • The general rules describing the evolution of the structure: endocytosis (moving an elementary membrane inside a neighbouring membrane) and exocytosis (moving an elementary membrane outside the membrane where it is placed). (
  • Mobile membranes represents a formalism which describes the movement of membranes inside a spatial structure by applying rules from a given set of rules R {\displaystyle R} . The mobility is provided by consumption and rewriting of objects. (
  • This can also be used as a metaphor for membrane pores. (
  • The technique of synthesis involves exposure of the cast membrane to humid air to create large surface pores on the exposed side. (
  • MilliporeSigma™ Immobilon™-FL PVDF Transfer Membranes are plain surfaced with 0.45μm pores and have lower background fluorescence than other membranes. (
  • New membranes with designer pores and surface shapes that enhance micro-mixing and shear flow across the membrane surface could be used to reduce the energy and down-time associated with cleaning blockages and fouling of the membranes. (
  • This invention relates generally to chemically activated microporous membranes. (
  • More particularly, this invention relates to polyaldehyde activated microporous membranes and a process for making the same. (
  • The present invention relates to a novel biosensor comprising an electrode membrane combination. (
  • The present invention also relates to novel compounds used in the electrode membrane combinations. (
  • The invention relates to a unique battery having an active, porous membrane and method of making the same. (
  • More specifically the invention relates to a sealed battery system having a porous, metal oxide membrane with uniform, physicochemically functionalized ion channels capable of adjustable ionic interaction. (
  • The invention relates to a membrane support system which applies tension to the membrane of a sound producing or sound receiving device, such as a speaker or a microphone, respectively. (
  • Membranes of photosynthetic bacteria. (
  • In the biotech and pharmaceutical industries, MF membranes offer the safety of a physical barrier to remove bacteria and other microbes. (
  • Learn, for example, about gut bacteria as they scavenge fatty acids to build new membranes and chloroplasts as they sense and adapt to cold. (
  • Additionally, this fascinating reference discusses up-to-date topics in the analytical and separation science, plus biomimetic membrane technology. (
  • CANTON, MASS. - FEBRUARY 06, 2018 - Sika, the worldwide market leader in thermoplastic roofing and waterproofing membranes, has published new product-specific Environmental Product Declarations (EPD) for its Sarnafil® S 327 and G 410 single-ply PVC roofing membranes. (
  • The master assignment consists of preparing membranes of selected precursors via sol-gel chemistry. (
  • The other main epithelial membrane type consists of serous membranes. (
  • 11. The membrane of claim 10, wherein the bubble point is from about 5 psid to about 15 psid. (
  • 11. The membrane of claim 10 in which said composition absorbs about 15% to about 25% of its dry weight of water. (
  • 13. The membrane of claim 10 in which the diffusion ratio for said composition is about 2500 to about 3500. (
  • 6. A method for purifying or separating mixtures comprising separating mixtures of substances using the membrane of claim 1. (
  • The rings then invaginate the membrane, contract like a drawstring, and, finally, detach the vesicle from the surface of the cell. (
  • The influence of several sol characteristics on membrane microstructure and properties is still unknown. (
  • It reviews the most recent advances in design and characteristics of synthetic liquid membrane transport. (
  • Characteristics of Natural Liquid Membranes. (
  • Due to these unique properties, the Jason® membrane exhibits beneficial handling characteristics such as distinct tear resistance, despite its low thickness of only 0.1 to 0.25 mm, and easy drapery and adaptation to the bone surface. (
  • In addition, substrates including certain membranes have been chemically activated with aldehyde functional groups using methods such as oxidation. (
  • A type of microporous membrane which is capable of reacting chemically with soluble or suspended species is the so-called "affinity membrane. (
  • Osmosis is the movement of water across a semipermeable membrane from a region of low solute concentration to a region of higher solute concentration. (
  • Synder's Reverse Osmosis (RO) membranes and systems can produce large volumes of ultrapure water with incredible efficiency. (
  • This reverse osmosis membrane filter has a high filtering capacity of 1,200 ML and can purify up to 50 gallons of water per day. (