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.
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
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.
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.
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.
Lipid A is the biologically active component of lipopolysaccharides. It shows strong endotoxic activity and exhibits immunogenic properties.
Sulfonic acid derivatives that are substituted with an aliphatic hydrocarbon group.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.
Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.
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.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
Detergent-insoluble CELL MEMBRANE components. They are enriched in SPHINGOLIPIDS and CHOLESTEROL and clustered with glycosyl-phosphatidylinositol (GPI)-anchored proteins.
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)
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.
An organism originally isolated from sewage, manure, humus, and soil, but recently found as a parasite in mammals and birds.
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Peroxides produced in the presence of a free radical by the oxidation of unsaturated fatty acids in the cell in the presence of molecular oxygen. The formation of lipid peroxides results in the destruction of the original lipid leading to the loss of integrity of the membranes. They therefore cause a variety of toxic effects in vivo and their formation is considered a pathological process in biological systems. Their formation can be inhibited by antioxidants, such as vitamin E, structural separation or low oxygen tension.
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.
A group of GLYCOLIPIDS in which the sugar group is GALACTOSE. They are distinguished from GLYCOSPHINGOLIPIDS in lacking nitrogen. They constitute the majority of MEMBRANE LIPIDS in PLANTS.
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.
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.
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.
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.
APOPTOSIS triggered by loss of contact with the EXTRACELLULAR MATRIX.
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.
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.
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.
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.
Established cell cultures that have the potential to propagate indefinitely.
Glycoproteins found on the membrane or surface of cells.
Cyclic GLUCANS consisting of seven (7) glucopyranose units linked by 1,4-glycosidic bonds.
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.
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).
FATTY ACIDS in which the carbon chain contains one or more double or triple carbon-carbon bonds.
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.
Compounds in which one or more of the three hydroxyl groups of glycerol are in ethereal linkage with a saturated or unsaturated aliphatic alcohol; one or two of the hydroxyl groups of glycerol may be esterified. These compounds have been found in various animal tissue.
Any compound containing one or more monosaccharide residues bound by a glycosidic linkage to a hydrophobic moiety such as an acylglycerol (see GLYCERIDES), a sphingoid, a ceramide (CERAMIDES) (N-acylsphingoid) or a prenyl phosphate. (From IUPAC's webpage)
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.
A breach in the continuity of the ANTERIOR CHAMBER of the eyeball.
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 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)
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.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters.
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.
Transport proteins that carry specific substances in the blood or across cell membranes.
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.
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.
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.
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.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
The rate dynamics in chemical or physical systems.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A 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)
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.
Proteins found in any species of bacterium.
Elements of limited time intervals, contributing to particular results or situations.
Chromatography on thin layers of adsorbents rather than in columns. The adsorbent can be alumina, silica gel, silicates, charcoals, or cellulose. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
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.
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.
Single membrane vesicles, generally made of PHOSPHOLIPIDS.
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)
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
Acidic phospholipids composed of two molecules of phosphatidic acid covalently linked to a molecule of glycerol. They occur primarily in mitochondrial inner membranes and in bacterial plasma membranes. They are the main antigenic components of the Wassermann-type antigen that is used in nontreponemal SYPHILIS SERODIAGNOSIS.
A class of membrane lipids that have a polar head and two nonpolar tails. They are composed of one molecule of the long-chain amino alcohol sphingosine (4-sphingenine) or one of its derivatives, one molecule of a long-chain acid, a polar head alcohol and sometimes phosphoric acid in diester linkage at the polar head group. (Lehninger et al, Principles of Biochemistry, 2nd ed)
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.
Measurement of the intensity and quality of fluorescence.
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)
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.
A family of enzymes that catalyze the stereoselective, regioselective, or chemoselective syn-dehydrogenation reactions. They function by a mechanism that is linked directly to reduction of molecular OXYGEN.
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
A complex of polyene antibiotics obtained from Streptomyces filipinensis. Filipin III alters membrane function by interfering with membrane sterols, inhibits mitochondrial respiration, and is proposed as an antifungal agent. Filipins I, II, and IV are less important.
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 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).
A change of a substance from one form or state to another.
The characteristic three-dimensional shape of a molecule.
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)
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
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 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.
Process of classifying cells of the immune system based on structural and functional differences. The process is commonly used to analyze and sort T-lymphocytes into subsets based on CD antigens by the technique of flow cytometry.
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)
A phenothiazine antipsychotic with effects similar to CHLORPROMAZINE.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
Minute projections of cell membranes which greatly increase the surface area of the cell.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
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.
RED BLOOD CELL sensitivity to change in OSMOTIC PRESSURE. When exposed to a hypotonic concentration of sodium in a solution, red cells take in more water, swell until the capacity of the cell membrane is exceeded, and burst.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.
A naphthalene derivative with carcinogenic action.
Steroids with a hydroxyl group at C-3 and most of the skeleton of cholestane. Additional carbon atoms may be present in the side chain. (IUPAC Steroid Nomenclature, 1987)
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
The sum of the weight of all the atoms in a molecule.
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.
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.
A clear, odorless, tasteless liquid that is essential for most animal and plant life and is an excellent solvent for many substances. The chemical formula is hydrogen oxide (H2O). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The relationship between the 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.
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 thermodynamic interaction between a substance and WATER.
A colorless liquid with a sharp burning taste and slight odor. It is used as a local anesthetic and to reduce pain associated with LIDOCAINE injection. Also, it is used in the manufacture of other benzyl compounds, as a pharmaceutic aid, and in perfumery and flavoring.
Salts and esters of the 12-carbon saturated monocarboxylic acid--lauric acid.
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.
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)
Proteins prepared by recombinant DNA technology.
A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.
Differential thermal analysis in which the sample compartment of the apparatus is a differential calorimeter, allowing an exact measure of the heat of transition independent of the specific heat, thermal conductivity, and other variables of the sample.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
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 sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Molecules which contain an atom or a group of atoms exhibiting an unpaired electron spin that can be detected by electron spin resonance spectroscopy and can be bonded to another molecule. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed)
A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.
A homologous group of cyclic GLUCANS consisting of alpha-1,4 bound glucose units obtained by the action of cyclodextrin glucanotransferase on starch or similar substrates. The enzyme is produced by certain species of Bacillus. Cyclodextrins form inclusion complexes with a wide variety of substances.
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)
Symptoms of disorders of the lower urinary tract including frequency, NOCTURIA; urgency, incomplete voiding, and URINARY INCONTINENCE. They are often associated with OVERACTIVE BLADDER; URINARY INCOMPETENCE; and INTERSTITIAL CYSTITIS. Lower urinary tract symptoms in males were traditionally called PROSTATISM.
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.
An ergot derivative that has been used as a cerebral vasodilator and in peripheral vascular disease. It has been suggested to ameliorate cognitive deficits in cerebrovascular disease.
A specific monosialoganglioside that accumulates abnormally within the nervous system due to a deficiency of GM1-b-galactosidase, resulting in GM1 gangliosidosis.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
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.
Proteins obtained from ESCHERICHIA COLI.
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
The relationship between the dose of an administered drug and the response of the organism to the drug.
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.
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.
Organic compounds containing a carbonyl group in the form -CHO.
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.
Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.
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.
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.
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 steroid of interest both because its biosynthesis in FUNGI is a target of ANTIFUNGAL AGENTS, notably AZOLES, and because when it is present in SKIN of animals, ULTRAVIOLET RAYS break a bond to result in ERGOCALCIFEROL.
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.
The dialdehyde of malonic acid.
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 resistance that a gaseous or liquid system offers to flow when it is subjected to shear stress. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
A group of 16-carbon fatty acids that contain no double bonds.
Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.
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.
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.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
A benzofuran derivative used as a protein reagent since the terminal N-NBD-protein conjugate possesses interesting fluorescence and spectral properties. It has also been used as a covalent inhibitor of both beef heart mitochondrial ATPase and bacterial ATPase.
The ability of a substrate to allow the passage of ELECTRONS.
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.
Characteristics or attributes of the outer boundaries of objects, including molecules.
Fatty acid derivatives of glycerophosphates. They are composed of glycerol bound in ester linkage with 1 mole of phosphoric acid at the terminal 3-hydroxyl group and with 2 moles of fatty acids at the other two hydroxyl groups.
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)
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.
Endocytic/exocytic CELL MEMBRANE STRUCTURES rich in glycosphingolipids, cholesterol, and lipid-anchored membrane proteins that function in ENDOCYTOSIS (potocytosis), transcytosis, and SIGNAL TRANSDUCTION. Caveolae assume various shapes from open pits to closed vesicles. Caveolar coats are composed of CAVEOLINS.
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.
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
Unsaturated azacyclopropane compounds that are three-membered heterocycles of a nitrogen and two carbon atoms.
A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.
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.
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.
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.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
Members of the class of neutral glycosphingolipids. They are the basic units of SPHINGOLIPIDS. They are sphingoids attached via their amino groups to a long chain fatty acyl group. They abnormally accumulate in FABRY DISEASE.
Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.
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.
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.
The process of cleaving a chemical compound by the addition of a molecule of water.
An unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. (Stedman, 26th ed)
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.
The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.
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 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.
A trihydroxy sugar alcohol that is an intermediate in carbohydrate and lipid metabolism. It is used as a solvent, emollient, pharmaceutical agent, and sweetening agent.
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.
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).)
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.
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)
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.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Derivatives of PHOSPHATIDYLCHOLINES obtained by their partial hydrolysis which removes one of the fatty acid moieties.
The network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
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.
Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).
Adaptation to a new environment or to a change in the old.
An absence of warmth or heat or a temperature notably below an accustomed norm.

Formation of lipid-linked sugar compounds in Halobacterium salinarium. Presumed intermediates in glycoprotein synthesis. (1/4162)

The ability of bacitracin to inhibit the growth of Halobacterium salinarium suggested that glycosylation of the major envelope component, a high molecular weight glycoprotein, might occur via a pathway involving lipid intermediates. This report demonstrates that the cells have enzymatic activities for formation of lipid-linked sugar compounds having the expected properties of such intermediates. Whole cell homogenate catalyzed the transfer of sugar from UDP-glucose, GDP-mannose, and UDP-N-acetyglucosamine to endogenous lipid acceptors. Two lipid products were formed from UDP-glucose, two from GDP-mannose, and one from UDP-N-acetylglucosamine. Characterization of the partially purified lipids by ion exchange chromatography, thin layer chromatography, and mild acid and base hydrolysis showed the major product in each case to have the properties expected for polyisoprenyl phosphoglucose, polyisoprenyl phosphomannose, and polyisoprenyl pyrophospho-N-acetylglucosamine. Estimates of chain length by thin layer chromatography indicate that the lipid has 11 to 12 isoprene identity as a C55-60-polyisoprenyl pyrophospho-N-acetylglucosamine. The N-acetylglucosamine transferase, present in cell envelope preparations, was partially characterized. The enzyme was found to be extremely halophilic, specifically requiring a high concentration of KCl. Optimum activity was obtained at 4 m KCl and partial substitution of K+ by Na+ resulted in a decrease in activity.  (+info)

Efficient binding of regulated secretory protein aggregates to membrane phospholipids at acidic pH. (2/4162)

Some regulated secretory proteins are thought to be targeted to secretory granules through an acidic-dependent aggregation in the trans-Golgi network. In this report we use pancreatic zymogens, a paradigm of regulated proteins, to test this hypothesis, because they qualitatively aggregate upon acidification in vitro. Pig zymogens were found to start to aggregate significantly at pH approximately 6.0, a pH slightly lower than that at which rat zymogens aggregate, but still compatible with the pH of the cell-sorting compartments. When pig zymogen granule membranes were mixed with the zymogens in the aggregation assay, membranes that normally floated on 1 M sucrose were observed to be pelleted by the aggregating zymogens. Rat membranes were pelleted by pig zymogens and vice versa. Igs, typical constitutively secreted proteins, which needed chemical cross-linking to serve as an aggregated protein control, pelleted membranes almost independently of pH. Corresponding cross-linked zymogen-binding ability and pH dependence was unaffected by the chemical modification. Membranes treated with sodium carbonate, pH 11, or with protease K, were still pelleted by zymogens, suggesting that the aggregated zymogens bound to membrane lipids. This hypothesis was confirmed by the efficient pelleting of unilamellar vesicles composed of granule membrane lipids. Vesicles composed of single classes of phospholipids were also pelleted, but with various efficacies. We conclude that pancreatic zymogen aggregates, formed under the acidic conditions of the secretory pathway sorting compartments, have the capacity to bind firmly to membranes through their phospholipid constituents.  (+info)

Molecular dynamics on a model for nascent high-density lipoprotein: role of salt bridges. (3/4162)

The results of an all-atom molecular dynamics simulation on a discoidal complex made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and a synthetic alpha-helical 18-mer peptide with an apolipoprotein-like charge distribution are presented. The system consists of 12 acetyl-18A-amide (Ac-18A-NH2) (. J. Biol. Chem. 260:10248-10255) molecules and 20 molecules of POPC in a bilayer, 10 in each leaflet, solvated in a sphere of water for a total of 28,522 atoms. The peptide molecules are oriented with their long axes normal to the bilayer (the "picket fence" orientation). This system is analogous to complexes formed in nascent high-density lipoprotein and to Ac-18A-NH2/phospholipid complexes observed experimentally. The simulation extended over 700 ps, with the last 493 ps used for analysis. The symmetry of this system allows for averaging over different helices to improve sampling, while maintaining explicit all-atom representation of all peptides. The complex is stable on the simulated time scale. Several possible salt bridges between and within helices were studied. A few salt bridge formations and disruptions were observed. Salt bridges provide specificity in interhelical interactions.  (+info)

Surface-induced polymerization of actin. (4/4162)

Living cells contain a very large amount of membrane surface area, which potentially influences the direction, the kinetics, and the localization of biochemical reactions. This paper quantitatively evaluates the possibility that a lipid monolayer can adsorb actin from a nonpolymerizing solution, induce its polymerization, and form a 2D network of individual actin filaments, in conditions that forbid bulk polymerization. G- and F-actin solutions were studied beneath saturated Langmuir monolayers containing phosphatidylcholine (PC, neutral) and stearylamine (SA, a positively charged surfactant) at PC:SA = 3:1 molar ratio. Ellipsometry, tensiometry, shear elastic measurements, electron microscopy, and dark-field light microscopy were used to characterize the adsorption kinetics and the interfacial polymerization of actin. In all cases studied, actin follows a monoexponential reaction-limited adsorption with similar time constants (approximately 10(3) s). At a longer time scale the shear elasticity of the monomeric actin adsorbate increases only in the presence of lipids, to a 2D shear elastic modulus of mu approximately 30 mN/m, indicating the formation of a structure coupled to the monolayer. Electron microscopy shows the formation of a 2D network of actin filaments at the PC:SA surface, and several arguments strongly suggest that this network is indeed causing the observed elasticity. Adsorption of F-actin to PC:SA leads more quickly to a slightly more rigid interface with a modulus of mu approximately 50 mN/m.  (+info)

Polarization-modulated FTIR spectroscopy of lipid/gramicidin monolayers at the air/water interface. (5/4162)

Monolayers of gramicidin A, pure and in mixtures with dimyristoylphosphatidylcholine (DMPC), were studied in situ at the air/H2O and air/D2O interfaces by polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS). Simulations of the entire set of amide I absorption modes were also performed, using complete parameter sets for different conformations based on published normal mode calculations. The structure of gramicidin A in the DMPC monolayer could clearly be assigned to a beta6.3 helix. Quantitative analysis of the amide I bands revealed that film pressures of up to 25-30 mN/m the helix tilt angle from the vertical in the pure gramicidin A layer exceeded 60 degrees. A marked dependence of the peptide orientation on the applied surface pressure was observed for the mixed lipid-peptide monolayers. At low pressure the helix lay flat on the surface, whereas at high pressures the helix was oriented almost parallel to the surface normal.  (+info)

Differences between the trypanosomal and human GlcNAc-PI de-N-acetylases of glycosylphosphatidylinositol membrane anchor biosynthesis. (6/4162)

De-N-acetylation of N-acetylglucosaminyl-phosphatidylino-sitol (GlcNAc-PI) is the second step of glycosylphosphatidylino-sitol (GPI) membrane anchor biosynthesis in eukaryotes. This step is a prerequisite for the subsequent processing of glucosaminyl-phosphatidylinositol (GlcN-PI) that leads to mature GPI membrane anchor precursors, which are transferred to certain proteins in the endoplasmic reticulum. In this article, we used a direct de-N-acetylase assay, based on the release of [14C]acetate from synthetic GlcN[14C]Ac-PI and analogues thereof, and an indirect assay, based on the mannosylation of GlcNAc-PI analogues, to study the substrate specificities of the GlcNAc-PI de-N-acetylase activities of African trypanosomes and human (HeLa) cells. The HeLa enzyme was found to be more fastidious than the trypanosomal enzyme such that, unlike the trypanosomal enzyme, it was unable to act on a GlcNAc-PI analogue containing 2-O-octyl-d- myo -inositol or on the GlcNAc-PI diastereoisomer containing l- myo -inositol (GlcNAc-P(l)I). These results suggest thatselective inhibition of the trypanosomal de-N-acetylase may be possible and that this enzyme should be considered as a possible therapeutic target. The lack of strict stereospecificity of the trypanosomal de-N-acetylase for the d- myo -inositol component was also seen for the trypanosomal GPI alpha-manno-syltransferases when GlcNAc-P(l)I was added to the trypanosome cell-free system, but not when GlcN-P(l)I was used. In an attempt to rationalize these data, we modeled the structure and dynamics of d-GlcNAcalpha1-6d- myo -inositol-1-HPO4-( sn )-3-glycerol and its diastereoisomer d-GlcNAcalpha1-6l- myo -inositol-1-HPO4-( sn )-3-glycerol. These studies indicate that the latter compound visits two energy minima, one of which resembles the low-energy conformer of former compound. Thus, it is conceivable that the trypanosomal de-N-acetylase acts on GlcNAc-P(l)I when it occupies a GlcNAc-PI-likeconformation and that GlcN-P(l)I emerging from the de-N-acetylase may be channeled to the alpha-mannosyltransferases in this conformation.  (+info)

Interaction between terminal complement proteins C5b-7 and anionic phospholipids. (7/4162)

We have recently shown that C5b-6 binds to the erythrocyte membrane via an ionic interaction with sialic acid before the addition of C7 and subsequent membrane insertion. In this study we assessed the role of anionic lipids in the binding of the terminal complement proteins to the membrane and the efficiency of subsequent hemolysis. Human erythrocytes were modified by insertion of dipalmitoyl phosphatidylcholine (DPPC), dipalmitoyl phosphatidylserine (DPPS), dipalmitoyl phosphatidylethanolamine (DPPE), or dipalmitoyl phosphatidic acid (DPPA). Lipid incorporation and the hemolytic assays were done in the presence of 100 micromol/L sodium orthovanadate to prevent enzymatic redistribution of lipid. We found that the neutral lipids, DPPC and DPPE, did not affect C5b-7 uptake or hemolysis by C5b-9. In contrast, the two acidic phospholipids, DPPS and DPPA, caused a dose-dependent increase in both lysis and C5b-7 uptake. We conclude that the presence of anionic lipids on the exterior face of the membrane increases C5b-7 uptake and subsequent hemolysis. It is known that sickle cell erythrocytes have increased exposure of phosphatidylserine on their external face and are abnormally sensitive to lysis by C5b-9. The data presented here provide a plausible mechanism for this increased sensitivity.  (+info)

Nitric-oxide-induced apoptosis in human leukemic lines requires mitochondrial lipid degradation and cytochrome C release. (8/4162)

We have previously shown that nitric oxide (NO) stimulates apoptosis in different human neoplastic lymphoid cell lines through activation of caspases not only via CD95/CD95L interaction, but also independently of such death receptors. Here we investigated mitochondria-dependent mechanisms of NO-induced apoptosis in Jurkat leukemic cells. NO donor glycerol trinitrate (at the concentration, which induces apoptotic cell death) caused (1) a significant decrease in the concentration of cardiolipin, a major mitochondrial lipid; (2) a downregulation in respiratory chain complex activities; (3) a release of the mitochondrial protein cytochrome c into the cytosol; and (4) an activation of caspase-9 and caspase-3. These changes were accompanied by an increase in the number of cells with low mitochondrial transmembrane potential and with a high level of reactive oxygen species production. Higher resistance of the CD95-resistant Jurkat subclone (APO-R) cells to NO-mediated apoptosis correlated with the absence of cytochrome c release and with less alterations in other mitochondrial parameters. An inhibitor of lipid peroxidation, trolox, significantly suppressed NO-mediated apoptosis in APO-S Jurkat cells, whereas bongkrekic acid (BA), which blocks mitochondrial permeability transition, provided only a moderate antiapoptotic effect. Transfection of Jurkat cells with bcl-2 led to a complete block of apoptosis due to the prevention of changes in mitochondrial functions. We suggest that the mitochondrial damage (in particular, cardiolipin degradation and cytochrome c release) induced by NO in human leukemia cells plays a crucial role in the subsequent activation of caspase and apoptosis.  (+info)

Clear protocols for the study of membrane lipid properties, cellular transport or signal transduction are presented in this manual. Following a short introduction to membrane lipids, techniques for the isolation and extraction of membrane fractions, the analysis of the lipid composition, lipid turnover, and the involvement in signal transduction as well as the preparation of liposomes are : Paperback.. Clear protocols for the study of membrane lipid properties, cellular transport or signal transduction are Manual on Membrane Lipids. Authors: Prasad, Rajendra Free Preview.. Buy this book eB08 About this book. Clear protocols for the study of membrane lipid properties, cellular transport or signal transduction are presented in this manual. Following a short introduction to membrane lipids, techniques for the isolation and extraction of membrane fractions, the analysis of the lipid composition, lipid turnover, and the involvement in signal transduction as well as the preparation of liposomes are ...
Lipid rafts are cholesterol- and glycosphingolipids- enriched microdomains on plasma membrane surface of mammal cells, involved in a variety of cellular processes. Depleting cholesterol from the plasma membrane by drugs influences the trafficking of lipid raft markers. Optical imaging techniques are powerful tools to study lipid rafts in live cells due to its noninvasive feature. In this study, breast cancer cells MCF-7 were treated with different concentrations of MβCD to deplete cholesterol and an environmentally sensitive fluorescence probe, Laurdan was loaded to image lipid order by two-photon microscopy. The generalized polarization (GP) values were calculated to distinguish the lipid order and disorder phase. GP images and GP distributions of native and cholesterol-depleted MCF-7 cells were obtained. Our results suggest that even at low concentration (0.5 mM) of MβCD, the morphology of the MCF-7 cells changes. Small high GP areas (lipid order phase) decrease more rapidly than low GP ...
Source: Campbell Biology Variations in the cell membrane lipid compositions of many species appear to be evolutionary adaptations that maintain the appropriate membrane fluidity under specific environmental conditions. For instance, fishes that live in extreme cold have membranes with a high proportion of unsaturated hydrocarbon tails, enabling their membranes to remain fluid. At the…
Purchase Lipid Polymorphism and Membrane Properties, Volume 44 - 1st Edition. Print Book & E-Book. ISBN 9780121533441, 9780080585154
A membrane lipid is a compound which belongs to a group of (structurally similar to fats and oils) which form the double-layered surface of all cells (lipid bilayer). The three major classes of membrane lipids are phospholipids, glycolipids, and cholesterol. Lipids are amphiphilic: they have one end that is soluble in water (polar) and an ending that is soluble in fat (nonpolar). By forming a double layer with the polar ends pointing outwards and the nonpolar ends pointing inwards membrane lipids can form a lipid bilayer which keeps the watery interior of the cell separate from the watery exterior. The arrangements of lipids and various proteins, acting as receptors and channel pores in the membrane, control the entry and exit of other molecules and ions as part of the cells metabolism. In order to perform physiological functions, membrane proteins are facilitated to rotate and diffuse laterally in two dimensional expanse of lipid bilayer by the presence of a shell of lipids closely ...
In eukaryotic cells, the membranes of different intracellular organelles have different lipid composition, and various biomembranes show an asymmetric distribution of lipid types across the membrane bilayer. Membrane lipid organization reflects a dynamic equilibrium of lipids moving across the bilayer in both directions. In this review, we summarize data supporting ... read more the role of specific membrane proteins in catalyzing transbilayer lipid movement, thereby controlling and regulating the distribution of lipids over the leaflets of biomembranes. show less ...
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Various structural components of biological membranes are asymmetrically localized in the two surfaces of the membrane bilayer. This asymmetry is absolute for membrane (glyco) proteins, but only a partial asymmetry has been observed for membrane phospholipids. In the red cell membrane, choline-phospholipids are localized mainly in the outer monolayer whereas aminophospholipids are distributed almost exclusively in the inner monolayer. Several evidences are now available to suggest that this distribution of membrane phospholipids in red cells is directly or indirectly maintained by the membrane-associated cytoskeleton (membrane skeleton). This belief is well supported by the previous as well as recent studies carried out in the authors laboratory. Previously, it has been shown that lipid-lipid interactions play no major role in maintaining the transmembrane phospholipid asymmetry in erythrocytes, and that the asymmetry is lost upon covalent crosslinking of the major membrane skeletal protein, ...
en] Biological membranes are complex structures composed largely of proteins and lipids. These components have very different structural and physical properties and consequently they do not form a single homogeneous mixture. Rather components of the mixture are more enriched in some regions than in others. This can be demonstrated with simple lipid mixtures that spontaneously segregate components so as to form different lipid phases that are immiscible with one another. The segregation of molecular components of biological membranes also involves proteins. One driving force that would promote the segregation of membrane components is the preferential interaction between a protein and certain lipid components. Among the varied lipid components of mammalian membranes, the structure and physical properties of cholesterol is quite different from that of other major membrane lipids. It would therefore be expected that in many cases proteins would have very different energies of interaction with ...
Membranes are barriers which regulate the transformation of information between cells. Biological membranes are inert barriers which plays an important rol..
Study Membrane Lipids flashcards from Harrison Mcumber's Tufts class online, or in Brainscape's iPhone or Android app. ✓ Learn faster with spaced repetition.
This task aims to unveil the morpho-functional basis of the highly organized structure and function of invadopodia in tumour cells. The role of membrane lipids, particularly cholesterol and caveolin 1, will be studied through the manipulation of membrane lipid composition. 1.2 Role of Fgd1 and podoplanin in linking ECM-cell interactions and formation of invadopodia ...
This task aims to unveil the morpho-functional basis of the highly organized structure and function of invadopodia in tumour cells. The role of membrane lipids, particularly cholesterol and caveolin 1, will be studied through the manipulation of membrane lipid composition. 1.2 Role of Fgd1 and podoplanin in linking ECM-cell interactions and formation of invadopodia ...
in Chemistry and Physics of Lipids (2002), 120(1-2), 57-74. Increasing evidence implicates interactions between Abeta-peptides and membrane lipids in Alzheimers disease. To gain insight into the potential role of the free amino group of the N-terminus of Abeta29 ... [more ▼]. Increasing evidence implicates interactions between Abeta-peptides and membrane lipids in Alzheimers disease. To gain insight into the potential role of the free amino group of the N-terminus of Abeta29-42 fragment in these processes, we have investigated the ability of Abeta29-42 unprotected and Abeta29-42 N-protected to interact with negatively-charged liposomes and have calculated the interaction with membrane lipids by conformational analysis. Using vesicles mimicking the composition of neuronal membranes, we show that both peptides have a similar capacity to induce membrane fusion and permeabilization. The fusogenic effect is related to the appearance of non-bilayer structures where isotropic motions occur as shown ...
Richard Grosss research is focused on the chemical biology of member in health and disease. Biologic membranes are comprised of a structurally diverse array of thousands of distinct chemical entities in a bilayer configuration that are in constant motion providing a rich repertoire of chemical forces that can be used to modulate the conformation and function of transmembrane proteins such as ion channels and ion pumps. Through adaptation of a bilayer structure membranes serve as a hydrophobic scaffold for the organization of complex supramolecular chemical assemblies that are used in biologic systems as signaling platforms ...
Membrane-binding interfaces of peripheral proteins are restricted to a small part of their exposed surface, so the ability to engage in strong selective interactions with membrane lipids at various depths in the interface ...
Cholesterol- and glycosphingolipid-enriched membrane lipid microdomains, frequently called lipid rafts, are thought to play an important role in the spatial and temporal organization of immunological synapses. Higher ordering of lipid acyl chains was suggested for these entities and imaging of membrane order in living cells during activation can therefore help to understand the mechanisms responsible for the supramolecular organization of molecules involved in the activation of T cells. Here, we employ the phase-sensitive membrane dye di-4-ANEPPDHQ together with a variety of spectrally-resolved microscopy techniques, including 2-channel ratiometric TIRF microscopy and fluorescence lifetime imaging, to characterize membrane order at the T cell immunological synapse at high spatial and temporal resolution in live cells at physiological temperature. We find that higher membrane order resides at the immunological synapse periphery where proximal signalling through the immunoreceptors and accessory proteins
Loffhagen, N.; Haertig, C.; Benndorf, D.; Babel, W., 2002: Effects of growth temperature and lipophilic carbon sources on the fatty acid composition and membrane lipid fluidity of Acinetobacter calcoaceticus 69V
The phenotypic adaptation of membrane lipids in seven strains of the food-poisoning bacterium Bacillus cereus, isolated from Bangladeshi rice, is reported in relation to their ability to grow under conditions of low water activity (a w), reduced temperature and the presence of soluble rice starch. The strains have different membrane phospholipid head-group and fatty acyl compositions, and they display individual differences in their responses to both low a w and reduced temperature. The extent of the increase in anionic membrane lipids in response to low a w varies from strain to strain, is solute specific and in one strain does not occur. Growth is stimulated by the presence of soluble rice starch and results in a large rise in the proportion of diphosphatidylglycerol (DPG) at the expense of phosphatidylglycerol (PG), without any change in the proportion of total anionic phospholipids. Growth at 15 °C compared with 37 °C increases the proportions of DPG and phosphatidylethanolamine at the expense of
The membrane lipid composition of living cells generally adjusts to the prevailing environmental and physiological conditions. In this study, membrane activity and lipid composition of the Gram-negative bacterium Vibrio sp. DSM14379, grown aerobically in a peptone-yeast extract medium supplemented with 0.5, 1.76, 3, 5 or 10% (w/v) NaCl, was determined. The ability of the membrane to reduce a spin label was studied by EPR spectroscopy under different salt concentrations in cell suspensions labeled with TEMPON. For lipid composition studies, cells were harvested in a late exponential phase and lipids were extracted with chloroform-methanol-water, 1:2:0.8 (v/v). The lipid polar head group and acyl chain compositions were determined by thin-layer and gas-liquid chromatographies. 31P-NMR spectroscopy was used to study the phase behaviour of the cell lipid extracts with 20 wt.% water contents in a temperature range from −10 to 50 °C. The results indicate that the ability of the membrane to reduce ...
Read Effect of Wheatgrass on Membrane Fatty Acid Composition During Hepatotoxicity Induced by Alcohol and Heated PUFA, The Journal of Membrane Biology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
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Starke-Peterkovic, T., Turner, N., Else, P. & Clarke, R. (2005). Electrical field strength of membrane lipids from vertebrate species: membrane lipid composition and Na+-K+-ATPase molecular activity. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 288 R663-R670.. ...
Proteins embedded in the plasma membrane mediate interactions with the cell environment and play decisive roles in many signaling events. For cell-cell recognition molecules, it is highly likely that their structures and behavior have been optimized in ways that overcome the limitations of membrane tethering. In particular, the ligand binding regions of these proteins likely need to be maximally exposed. Here we show by means of atomistic simulations of membrane-bound CD2, a small cell adhesion receptor expressed by human T-cells and natural killer cells, that the presentation of its ectodomain is highly dependent on membrane lipids and receptor glycosylation acting in apparent unison. Detailed analysis shows that the underlying mechanism is based on electrostatic interactions complemented by steric interactions between glycans in the protein and the membrane surface. The findings are significant for understanding the factors that render membrane receptors accessible for binding and signaling.
Understanding of cell membrane organization has evolved significantly from the classic fluid mosaic model. It is now recognized that biological membranes are highly organized structures, with differences in lipid compositions between inner and outer leaflets and in lateral structures within the bilayer plane, known as lipid rafts. These organizing principles are important for protein localization and function as well as cellular signaling. However, the mechanisms and biophysical basis of lipid raft formation, structure, dynamics and function are not clearly understood. One key question, which we focus on in this review, is how lateral organization and leaflet compositional asymmetry are coupled. Detailed information elucidating this question has been sparse because of the small size and transient nature of rafts and the experimental challenges in constructing asymmetric bilayers. Resolving this mystery will require advances in both experimentation and modeling. We discuss here the preparation of ...
This paper explores the interaction mechanism between the conjugated polyelectrolyte {[9,9-bis(6-N,N,N-trimethylammonium)hexyl]fluorene-phenylene}bromide (HTMA-PFP) and model lipid membranes. The study was carried out using different biophysical techniques, mainly fluorescence spectroscopy and microscopy. Results show that despite the preferential interaction of HTMA-PFP with anionic lipids, HTMA-PFP shows affinity for zwitterionic lipids; although the interaction mechanism is different as well as HTMA-PFPs final membrane location. Whilst the polyelectrolyte is embedded within the lipid bilayer in the anionic membrane, it remains close to the surface, forming aggregates that are sensitive to the physical state of the lipid bilayer in the zwitterionic system. The different interaction mechanism is reflected in the polyelectrolyte fluorescence spectrum, since the maximum shifts to longer wavelengths in the zwitterionic system. The intrinsic fluorescence of HTMA-PFP was used to visualize the interaction
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One of the popular approaches to study cell membranes is to study lipid mixtures phase behaviors. Although the structure of compositionally simple binary and ternary lipid systems have been extensively studied in the last three decades, the effects of proteins on compositional complexity of biological membranes have not been studied in details. Since in some biological membranes, the majority of membrane area is covered by proteins (up to 60-70%), it is reasonable to suppose that membrane proteins would have large effects on bilayer phase behavior. To the best of our knowledge, previously, no 4-component phase diagram, with protein as one of the components, has been reported. This work is the first study of this kind which investigate the effect of polypeptide gramicidin-A on Lo+Ld phase boundaries. In recent years, many studies have focused on the study of lipid rafts, a type of domain structure thought to form spontaneously by lateral phase separation in membranes. Lipid rafts provide domains ...
One of the popular approaches to study cell membranes is to study lipid mixtures phase behaviors. Although the structure of compositionally simple binary and ternary lipid systems have been extensively studied in the last three decades, the effects of proteins on compositional complexity of biological membranes have not been studied in details. Since in some biological membranes, the majority of membrane area is covered by proteins (up to 60-70%), it is reasonable to suppose that membrane proteins would have large effects on bilayer phase behavior. To the best of our knowledge, previously, no 4-component phase diagram, with protein as one of the components, has been reported. This work is the first study of this kind which investigate the effect of polypeptide gramicidin-A on Lo+Ld phase boundaries. In recent years, many studies have focused on the study of lipid rafts, a type of domain structure thought to form spontaneously by lateral phase separation in membranes. Lipid rafts provide domains ...
The work presents in this thesis has been focused on structural characterization of a series of selected well-defined molecular architectures for the application as biomimetic membranes. The molecular architectures were prepared by self-assembly from dilute solution onto gold substrates, so called self-assembled monolayers (SAMs).. Biological membranes are essential components for all living systems; their molecular organizations and interactions with intra- and extracellular networks are key factors of cell functions. Many important biological processes are regulated at membrane interfaces via interactions between membrane proteins. Therefore, identification of the cell structures and understanding of the processes associated with membranes are crucial. However, the intrinsic complexity of the cell membrane systems makes direct investigation extra difficult. Based on this reason, artificial model membranes have become a useful strategy. Especially, solid supported tethered lipid membranes on ...
Cells maintain membrane fluidity by regulating lipid saturation, but the molecular mechanisms of this homeoviscous adaptation remain poorly understood. We have reconstituted the core machinery for regulating lipid saturation in bakers yeast to study its molecular mechanism. By combining molecular dynamics simulations with experiments, we uncover a remarkable sensitivity of the transcriptional regulator Mga2 to the abundance, position, and configuration of double bonds in lipid acyl chains, and provide insights into the molecular rules of membrane adaptation. Our data challenge the prevailing hypothesis that membrane fluidity serves as the measured variable for regulating lipid saturation. Rather, we show that Mga2 senses the molecular lipid-packing density in a defined region of the membrane. Our findings suggest that membrane property sensors have evolved remarkable sensitivities to highly specific aspects of membrane structure and dynamics, thus paving the way toward the development of genetically
Lipids are non-polar (hydrophobic) compounds, soluble in organic solvents. Most membrane lipids are amphipathic, having a non-polar end and a polar end. Fatty acids consist of a hydrocarbon chain with a carboxylic acid at one end. A 16-C fatty acid: CH 3 (CH 2 ) 14 - COO - Non-polar polar A 16-C fatty acid with one cis double bond between C atoms 9-10 may be represented as 16:1 cis  9.
Biomimetic giant membrane vesicles, with size and lipid compositions comparable to cells, have been recognized as an attractive experimental alternative to living systems. Due to the similarity of their membrane structure to that of body cells, cell-derived giant plasma membrane vesicles have been used as a membrane model for studying lipid/protein behavior of plasma membranes. However, further application of biomimetic giant membrane vesicles has been hampered by the side-effects of chemical vesiculants and the utilization of osmotic buffer. We herein develop a facile strategy to derive giant membrane vesicles (GMVs) from mammalian cells in biofriendly medium with high yields. These GMVs preserve membrane properties and adaptability for surface modification and encapsulation of exogenous molecules, which would facilitate their potential biological applications. Moreover, by loading GMVs with therapeutic drugs, GMVs could be employed for drug transport to tumor cells, which represents another step
Biological membranes are laminar bilayers of lipoids with thermolabile biophysical properties. Changing temperatures not only result in altered polarity and permeability of the membranes, but also in ...
Biological Membrane Png - Cell membrane Biological membrane Phospholipid Membrane protein ... #2173663 - Free Portable Network Graphics (PNG) Archive -
Richard E. Dick Pagano, a pioneer scientist in lipid cell biology, recently died at the age of 66. At the time, he was the head of a vibrant and productive laboratory in the department of biochemistry and molecular biology at the Mayo Clinic College of Medicine in Rochester, Minn. An overarching theme of Dicks research for the past 45 years was the innovative application of lipid biophysics and imaging technology to understanding the molecular organization of cell membrane lipids.. Dick trained with Thomas E. Thompson at the University of Virginia, where he received his doctoral degree in biophysics, studying ion permeability in model membranes. He continued to work with model membrane systems during his postdoctoral work with Norman L. Gershfeld at the National Institutes of Health and then with Israel R. Miller at the Weizmann Institute. During a brief fellowship in Dennis Chapmans lab at the University of Sheffield, Dick performed some of the first direct measurements confirming that gel ...
Author: Dahmen-Levison, U. et al.; Genre: Journal Article; Published in Print: 2000; Title: Investigations of lipid-protein interactions on monolayers of chain-substituted phosphatidylcholines.
A. Lipid Order Parameter in the Presence of Amphiphilic Molecules The outer lipid membrane surface of eukaryotic cells is generally uncharged. Amphiphilic, water-soluble molecules such as local anesthetics, viral or antibiotic pep-tides, or peptide toxins therefore partition into the bilayer […]
Important element All Living 18% Human body Protein Structure Amino acid sequence Functions Regulation Hormones Transport Hemoglobin Structure Hair and Nails Movement Muscle Fiber Defense Antibodies Lysine, Valine, Alanine Cereal Grains, Most foods, Meats ATP Nucleotide - 3 phosphate groups Carbon atoms can bond in Straight Chains, Branched Chains, or rings. Peptide bonds-join amino acids Phospholipid Bilayer Fats, Oils, Waxes, Steroids (cholesterol and hormones), and Water Proof Coating. Cell Membrane Lipids Chains, Branched, or Rings Deoxyribonucleic ...
Martínez-Páramo S, Diogo P, Dinis MT, Herráez MP, Sarasquete C, Cabrita E. Sea bass sperm freezability is influenced by motility variables and membrane lipid composition but not by membrane integrity and lipid peroxidation. Anim Reprod Sci. 2012;131(3-4):211-8. doi:10.1016/j.anireprosci.2012.03.008 ...
Poxviruses replicate in the cytoplasm, where they acquire multiple lipoprotein membranes. Although a proposal that the initial membrane arises de novo has not been substantiated, there is no accepted explanation for its formation from cellular membranes. A subsequent membrane-wrapping step involving modified trans-Golgi or endosomal cisternae results in a particle with three membranes. These wrapped virions traverse the cytoplasm on microtubules; the outermost membrane is lost during exocytosis, the middle one is lost just prior to cell entry, and the remaining membrane fuses with the cell to allow the virus core to enter the cytoplasm and initiate a new infection.
Biological membranes contain a great variety of lipids with different hydrocarbon chains, polar groups, backbone structure (glycerol or sphin-gosine), type of chemical linkage (ester or ether) of the...
Listing of the answers to the question: Proteins that are destined to become associated with the inner surface of the plasma membrane are:
...The lipid molecules of membranes also known as phospholipids are com...Biomembranes are constantly reorganized or renewed for example whenev... A helping hand through the membrane ...The problem is that the hydrophilic and lipophilic parts of the molecu...,Pathway,for,membrane,building,blocks,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
Membrane fluidity or membrane viscosity for short range lateral diffusion has best been measured using lipid analog probes that, when interacting, exhibit changes in their spectral…
M. A. Tahir, Van Lehn, R. C., Choi, S. H., and Alexander-Katz, A., Solvent-exposed lipid tail protrusions depend on lipid membrane composition and curvature, Biochimica Et Biophysica Acta-Biomembranes, vol. 1858, no. 6, pp. 1207 - 1215, 2016. ...
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.
Houston, J.E.; Kraft, M.; Scherf, U.; Evans, R.C., 2017: Sequential detection of multiple phase transitions in model biological membranes using a red-emitting conjugated polyelectrolyte
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Phospholipids - specialised lipids. They form a bilayer. Act as a barrier for water-soluble molecules between the cytoplasm and the outside. Their hydrocarbon tails are hydrophobic and point inwards. Held together by weak bonds. The phospholipid heads are hydrophilic and face outwards towards both the cytoplasm and the outside of the cell, both of which are water-based ...
Cell membranes are a mosaic of protein and lipid molecules, both of which can drift from place to place within the membrane. Most of the surface area...
Get this from a library! Biomembranes : Volume 2. [Lionel A Manson] -- Membranes and the Coordination of Cellular Activities.- Relations of Membrane Functions and Ultrastructure.- Biochemistry of Bacterial Membranes: The Complex Lipids.- Biochemical and Genetic Studies ...
Proteins Membrane Binding and Pore Formation und Buchbewertungen gibt es auf Bücher können hier direkt online erworben werden.
Name Period Concept 7.1 Cellular membranes are fluid mosaics of lipids and proteins 1. The large molecules of all living things fall into just four main classes. Name them. 2. Explain what is meant when
The purpose of this product is to restore membrane fluidity throughout the body and optimize mitochondrial function. It contains a unique mitochondrial fuel
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Cronan JE, Rock CO (1996). "Biosynthesis of membrane lipids". In Neidhardt, F.C. (ed.). Escherichia coli and Salmonella: ...
... membrane lipids and proteins; cellular organelles, and nucleic acids. Precipitation by a method known as salting out can ... Membrane proteins often serve as receptors or provide channels for polar or charged molecules to pass through the cell membrane ... The membrane alone has a hydrophobic core through which polar or charged molecules cannot diffuse. Membrane proteins contain ... Others are membrane proteins that act as receptors whose main function is to bind a signaling molecule and induce a biochemical ...
Lipid kinases phosphorylate lipids in the cell, both on the plasma membrane as well as on the membranes of the organelles. The ... 2003). "Lipid Kinases Play Crucial and Multiple Roles in Membrane Trafficking and Signalling" (PDF). Histology and ... Sphingolipids are ubiquitous membrane lipids. Upon activation, sphingosine kinase migrates from the cytosol to the plasma ... In its dephosphorylated form, glucose can move back and forth across the membrane very easily. Mutations in the hexokinase gene ...
Lipids membraneEdit. As a graduate student at Stanford University, Kornberg's studied the rotation of phospholipids and defined ... Initially, Kornberg took advantage of expertise with lipid membranes gained from his graduate studies to devise a technique for ... for the first time the dynamics of lipids in the membrane[18]. Kornberg called the movement of lipid from one leaflet to the ... Kornberg, Roger David (1972). The Diffusion of Phospholipids in Membranes (PhD thesis). Stanford University. OCLC 38611465.. ...
ISBN 0-7167-2009-4. Stryer, Lubert (1995). "Biosynthesis of membrane lipids and steroids.". In: Biochemistry (Fourth ed.). New ... The energy released during this process is used to create a hydrogen ion (or proton) gradient across the inner membrane of the ... Cholesterol can be used as is, as a structural component of cellular membranes, or it can be used to synthesize the steroid ... However the inner mitochondrial membrane is impermeable to NADH and NAD+. Use is therefore made of two "shuttles" to transport ...
As the lipid bilayer of membranes is impermeable to most hydrophilic molecules (dissolved by water), cells have membrane ... During electroporation, the lipid molecules in the membrane shift position, opening up a pore (hole) that acts as a conductive ... The authors remark that montmorillonite is known to serve as a chemical catalyst, encouraging lipids to form membranes and ... Primitive reproduction can be envisioned when the clay bubbles burst, releasing the lipid membrane-bound product into the ...
Stryer, Lubert (1995). "Biosynthesis of membrane lipids and steroids.". In: Biochemistry (Fourth ed.). New York: W.H. Freeman ... Fatty acids are an integral part of the phospholipids that make up the bulk of the plasma membranes, or cell membranes, of ... All cells in the body need to manufacture and maintain their membranes and the membranes of their organelles. Whether they rely ... the plasma membrane and other membranes that enclose all the organelles within the cells, such as the nucleus, the mitochondria ...
Lipid Membrane lipids Sulfoquinovose Sulfoglycolysis Benson; Daniel, H; Wiser, R; et al. (1959). "A sulfolipid in plants". Proc ... CF1 bound to membranes was found to be much more resistant to heat and cold than solubilised protein. Mitochondrial coupling ... In 1959 A. A. Benson and coworkers discovered a new sulfur-containing lipid in plants and identified it as sulfoquinovosyl ... SQDGs have been found to be closely associated with certain membrane proteins. In some cases the (electrostatic) interactions ...
Atif, S.M.; Salam, N.; Ahmad, N.; Hasan, I.M.; Jamal, H.S.; Sudhanshu, A.; Azevedo, V.; Owais, M. (2008). "Sperm membrane lipid ... In this regard, he has compared lipid compositions of plasma membranes of both prokaryotic as well as eukaryotic cells. These ... Ahmad, N.; Masood, A. K.; Owais, M. (15 November 2001). "Fusogenic potential of prokaryotic membrane lipids". European Journal ... he demonstrated the fusogenic attributes of sperm plasma membrane lipids, and established the prophylactic potential of ...
... many lipid-binding proteins are cytosolic and localize to the membrane by binding only the headgroups of lipids. Perhaps the ... "Profiling membrane lipids in plant stress responses. Role of phospholipase D alpha in freezing-induced lipid changes in ... Although some lipid-binding proteins are able to insert themselves into membranes and could hypothetically recognize the type ... At sites of membrane budding or fusion, the membrane becomes or is highly curved. A major event in the budding of vesicles, ...
The hopanoid diplopterol orders membranes by interacting with lipid A, a common membrane lipid in bacteria, in ways similar to ... In Bradyrhizobium, hopanoids chemically bonded to lipid A increase membrane stability and rigidity, enhancing stress tolerance ... October 2014). "Covalently linked hopanoid-lipid A improves outer-membrane resistance of a Bradyrhizobium symbiont of legumes ... Sohlenkamp C, Geiger O (January 2016). "Bacterial membrane lipids: diversity in structures and pathways". FEMS Microbiology ...
The bacteria's outer membrane has endotoxin-like lipids. Their axial filaments consists of endoflagella and periplasmic ... Meningitis inflames and breaks down any protective membrane and cells surrounding the brain, spinal cord, and other parts of ... Only certain water-soluble substances can move across the blood-brain barrier, while lipid-soluble substances can easily move ... This inflammation of the membranes causes meningitis. Syphilis is a sexually transmitted disease that is brought upon by the ...
Hartmann, Marie-Andrée (2003). "5 Sterol metabolism and functions in higher plants". Lipid Metabolism and Membrane Biogenesis. ... The regulation of the biosynthesis of both sterols and some specific lipids occurs during membrane biogenesis. Through 13C- ...
To deliver the molecules to a site of action, the lipid bilayer can fuse with other bilayers such as the cell membrane, thus ... A liposome has an aqueous solution core surrounded by a hydrophobic membrane, in the form of a lipid bilayer; hydrophilic ... YashRoy R.C. (1990). "Lamellar dispersion and phase separation of chloroplast membrane lipids by negative staining electron ... Cevc, G; Richardsen, H (1993). "Lipid vesicles and membrane fusion". Advanced Drug Delivery Reviews. 38 (3): 207-232. doi: ...
Zhang, Yong-Mei; Rock, Charles O. (2008-03-01). "Membrane lipid homeostasis in bacteria". Nature Reviews Microbiology. 6 (3): ... Palmitic acid is also used to synthesize sphingosines, which play a role in cell membranes. The different types of beta- ... These uses include energy storage and creation of cell membranes. Fatty acids can also be used to synthesize prostaglandins, ... In order to adapt to their environment, bacteria alter the phospholipid composition of their membranes. Inhibiting this pathway ...
12 Lipids and Membranes.. *^ Fromm and Hargrove (2012), pp. 22-27.. *^ Voet (2005), pp. 382-385. ... which are the final degradation products of fats and lipids. Lipids, especially phospholipids, are also used in various ... Lipids are an integral part of our daily diet. Most oils and milk products that we use for cooking and eating like butter, ... Lipids comprises a diverse range of molecules and to some extent is a catchall for relatively water-insoluble or nonpolar ...
... while lipid-soluble antioxidants protect cell membranes from lipid peroxidation.[53] These compounds may be synthesized in the ... and that it protects membranes from oxidation by reacting with lipid radicals produced in the lipid peroxidation chain reaction ... Wang X, Quinn PJ (July 1999). "Vitamin E and its function in membranes". Progress in Lipid Research. 38 (4): 309-36. doi: ... Lipid 5[84] 200 (human)[85] Uric acid[edit]. Uric acid is by far the highest concentration antioxidant in human blood. Uric ...
Cooper RA, Durocher JR, Leslie MH (July 1977). "Decreased fluidity of red cell membrane lipids in abetalipoproteinemia". The ... More recent research has focused on different ways to supply the patient with Vitamin E. In 2018, the Journal of Lipid Research ... and a fasting lipid panel, though these tests are not confirmatory. As the disease is rare, though a genetics test is necessary ... vacuoles containing lipids are seen in enterocytes. This disorder may also result in fat accumulation in the liver (hepatic ...
le Maire M, Champeil P, Moller JV (November 2000). "Interaction of membrane proteins and lipids with solubilizing detergents". ... It would require surfactin to self-associate inside the membrane, since it cannot span across the cellular membrane. ... "Detergent-like action of the antibiotic peptide surfactin on lipid membranes". Biophysical Journal. 81 (3): 1547-54. Bibcode: ... as it is able to create a permeable environment for the lipid bilayer and causes disruption that solubilizes the membrane. For ...
The membrane that surrounds anammoxosomes in anammox bacteria contains unique lipids called "ladderane" lipids, which contain a ... The anammoxosome membrane is invaginated (folded in upon itself) to increase its surface area. The existence of membrane-bound ... Sinninghe, Damste (2002). "Linearly concatenated cyclobutane lipids form a dense bacterial membrane". Nature. 419 (6908): 708- ... Scalindua have two inner membranes instead of one inner and one outer membrane surrounding the cell wall. Cells within Ca. ...
"Linearly concatenated cyclobutane lipids form a dense bacterial membrane". Nature. 419 (6908): 708-712. Bibcode:2002Natur.419.. ... The compound is found in bacteria performing the anammox process where it forms part of a tight and very dense membrane ...
... of membrane lipids. The high abundance of ladderane lipids in the anammoxosome results in an exceptionally dense membrane with ... Anammoxosomes are enriched in the ladderane lipids shown at right. Analysis of the anammoxosome membranes from the bacterial ... "Linearly concatenated cyclobutane lipids form a dense bacterial membrane". Nature. 419 (6908): 708-712. Bibcode:2002Natur.419.. ... ladderane lipid tails and their incorporation into a full phosphatidylcholine lipid. Both routes leverage a small [2]-ladderene ...
Lambers JW, Terpstra W (October 1985). "Inactivation of chlorophyllase by negatively charged plant membrane lipids". Biochim. ... It is a membrane protein that is commonly known as chlase (EC, CLH) and systematically known as chlorophyll ... These two lipids cooperatively inhibit the activity of chlorophyllase, but this inhibition can be reversed by the presence of ... Finally, there is evidence that chlorophyllase has been found in the inner envelope membrane of chloroplast where it does not ...
van Meer G, Voelker DR, Feigenson GW (February 2008). "Membrane lipids: where they are and how they behave". Nature Reviews. ... PI(4,5)P2 is present on plasma membranes, PI(3)P on early endosomes, PI(3,5)P2 on late endosomes and PI(4)P on the trans Golgi ... These lipids on the surface of the endosomes help in the specific recruitment of proteins from the cytosol, thus providing them ... Molecules or ligands internalized from the plasma membrane can follow this pathway all the way to lysosomes for degradation or ...
van Tienhoven M, Atkins J, Li Y, Glynn P (2002). "Human neuropathy target esterase catalyzes hydrolysis of membrane lipids". J ... it sequentially hydrolyses both fatty acids from the major membrane lipid phosphatidylcholine, generating water-soluble ... In eukaryotic cells, NTE is anchored to the cytoplasmic face of the endoplasmic reticulum membrane. In mammals, it is ... J Lipid Res. 47 (9): 1940-9. doi:10.1194/jlr.M600185-JLR200. PMID 16799181. Kienesberger PC, Oberer M, Lass A, Zechner R (Apr ...
... s arise from either alterations in membrane lipids or structural proteins. Alterations in membrane lipids are seen ... "Decreased fluidity of red cell membrane lipids in abetalipoproteinemia". J. Clin. Invest. 60 (1): 115-21. doi:10.1172/JCI108747 ... Alteration in membrane structural proteins are seen in neuroacanthocytosis and McLeod syndrome. In liver dysfunction, ... In abetalipoproteinemia, there is deficiency of lipids and vitamin E causing abnormal morphology of RBCs. The diagnosis of ...
Keller studies the organization of lipids in membranes. Cell membranes are composed of lipids and proteins. Her early work " ... Her current main research focus is understanding how simple lipid mixtures within bilayer membranes give rise to membrane's ... Her graduate study was on the "interaction between Ion-channels and Lipid Membranes", supervised by Dr. Sol M. Gruner. She was ... CS1 maint: discouraged parameter (link) ASBMB LIPID RESEARCH DIVISION (2010). "Exploring Membranes: The Work of Sarah L. Keller ...
Bankaitis, Vytas A.; Garcia-Mata, Rafael; Mousley, Carl J. (2012-05-22). "Golgi Membrane Dynamics and Lipid Metabolism". ... A cisterna (plural cisternae) is a flattened membrane vesicle of the endoplasmic reticulum and Golgi apparatus. A Golgi stack ...
... from membrane currents, proteins, and chemical coupling to network oscillations, columnar and topographic architecture, and ... Voltage sensitive ion channels are glycoprotein molecules which extend through the lipid bilayer, allowing ions to traverse ... "A quantitative description of membrane current and its application to conduction and excitation in nerve". J. Physiol. 117 (4 ...
Other proteins and lipids can be added to the cell membrane. By these changes, the cell can adjust what it brings in or puts ... Proteins in the membraneEdit. Main article: Membrane protein. Proteins within the membrane are key to its working. These ... The cell membrane is a thin flexible layer around the cells of all living things. It is sometimes called the plasma membrane or ... Cell membrane. biological membrane that separates the interior of a cell from its outside environment ...
2009). «Association of genetic variants with chronic kidney disease in individuals with different lipid profiles». Int. J. Mol ... maternal single nucleotide polymorphisms in candidate genes that predispose to spontaneous preterm labor with intact membranes ...
EBOV is thought to infect humans through contact with mucous membranes or skin breaks.[54] After infection, endothelial cells ( ... some lipid solvents such as some alcohol-based products, detergents, sodium hypochlorite (bleach) or calcium hypochlorite ( ... Virions bud off from the cell, gaining their envelopes from the cellular membrane from which they bud. The mature progeny ... Bleeding from mucous membranes or from sites of needle punctures has been reported in 40-50% of cases.[31] This may cause ...
A lipid-linked core-oligosaccharide is assembled at the membrane of the endoplasmic reticulum and transferred to selected ... Oligosaccharyltransferase or OST (EC is a membrane protein complex that transfers a 14-sugar oligosaccharide from ... Yeast OST is composed of eight different membrane-spanning proteins in three subcomplexes (one of them is OST4).[7][8] These ... OST is a component of the translocon in the endoplasmic reticulum (ER) membrane. ...
Lipids, 2004, 131. vsk, nro 2, s. 215-22. *↑ Conjugated polyene fatty acids as membrane probes: preliminary characterization. ... Role of beer lipid-binding proteins in preventing lipid destabilization of foam. J. Agric. Food Chem., 2002, 50. vsk, nro 26, s ... Gunstone F.D. (1996). Fatty Acid and Lipid Chemistry. Berlin: Springer Verlag, 10. ISBN 0-8342-1342-7.. ... Endo S, Zhiping G, Takagi T. (1991). Lipid components of seven species of Basidiomycotina and three species of Ascomycotina. ...
C. acnes also provokes skin inflammation by altering the fatty composition of oily sebum.[45] Oxidation of the lipid squalene ... membrane. *Aphthous stomatitis. *oral candidiasis. *lichen planus. *leukoplakia. *pemphigus vulgaris. *mucous membrane ...
Lang F, Alevizopoulos K, Stournaras C (2013). "Targeting membrane androgen receptors in tumors". Expert Opin. Ther. Targets. 17 ... Recent results indicate androgens inhibit the ability of some fat cells to store lipids by blocking a signal transduction ... Androgens have also been found to signal through membrane androgen receptors, which are distinct from the classical nuclear ...
membrane. • nucleoplasm. • mitochondrial outer membrane. • mitochondrion. • cell nucleus. • cytosol. Biological process. • ... lipid binding. • RNA polymerase II transcription factor activity, ligand-activated sequence-specific DNA binding. • identical ...
It is a type of lipid which is a fat or fat-like molecule. Cholesterol is a special type of lipid that is called a steroid. ... Cholesterols main function is as a structural component of cell membranes. It is also the starting material for bile acids that ... Steroids are lipids that have a special chemical structure. This structure is made of four rings of carbon atoms. ... disease of artery walls in which white blood cells invade the vessel wall and become engorged with cholesterol and other lipids ...
Deamer and Branton demonstrated that the freeze-etch method split the lipid bilayer of membranes to reveal integral proteins ... His work led to a novel method of DNA sequencing and a more complete understanding of the role of membranes in the origin of ... Conversations with Bangham inspired his research on the role of membranes in the origin of life, and in 1985 Deamer ... His advisor was David Cornwell, a lipid biochemist, so Deamer focused on calcium interactions with fatty acid and phospholipid ...
... the molecular mechanism was uncovered as damage to the macrophage membrane's lipid raft integrity by decreasing membrane ... Therefore, macrophage membranes become susceptibile to bacterial infections.[11] Reproductive system[edit]. In experiments with ...
Possibly important to basement membrane architecture and tissue development, as a needed catalyst to make collagen IV.[37] ... Involved in glucose and lipid metabolism, although its mechanisms of action in the body and the amounts needed for optimal ...
Proteins that cross the membrane are surrounded by annular lipids, which are defined as lipids that are in direct contact with ... An integral membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All ... Single-pass membrane proteins cross the membrane only once, while multi-pass membrane proteins weave in and out, crossing ... Integral monotopic proteins are associated with the membrane from one side but do not span the lipid bilayer completely. ...
Its genome does not have a lipid membrane. Picornaviruses are found in mammals and birds. There are currently 80 species in ... These acids form a pore in the cell membrane through which RNA is injected [2]. Once inside the cell, the RNA un-coats and the ... After this time the cell plasma membrane becomes permeable, at 4-6 hours the virus particles assemble, and can sometimes be ...
Membrane gas separation. *Pressure swing adsorption. *Oxygen analyser *Electro-galvanic oxygen sensor ...
Cell membrane. Ether-linked lipids, pseudopeptidoglycan. Ester-linked lipids, peptidoglycan. Ester-linked lipids, various ... They have membranes composed of glycerol-ether lipids, whereas bacteria and eukaryotes have membranes composed mainly of ... No membrane-bound organelles (questioned[56]) or nucleus. No membrane-bound organelles or nucleus. Membrane-bound organelles ... MembranesEdit. Membrane structures. Top, an archaeal phospholipid: 1, isoprene chains; 2, ether linkages; 3, L-glycerol moiety ...
After size fractionation of FCS and analysis of the lipids that bound to serum albumin, the lysophosphatidic acid (LPA) was ... The comparison with the normal cells showed that Rac1 stimulates actin filament production at the membrane, pinocytosis, and ... The inhibition of endogenous Rac function by mutants N17rac and V12rac1 prevented growth factor-induced membrane ruffling. In ... but had no effect on membrane ruffling. These findings were published in Cell and cited over 4000 times.[7] In parallel with ...
... assisting in the formation of lipid rafts in the plasma membrane. It also reduces the permeability of the plasma membrane to ... Haines TH (2001). "Do sterols reduce proton and sodium leaks through lipid bilayers?". Prog. Lipid Res. 40 (4): 299-324. doi: ... Cholesterol is required to build and maintain cell membranes; it regulates membrane fluidity over a wide range of temperatures ... මූලික ලිපියන්: hypercholesterolemia සහ lipid hypothesis. According to the lipid hypothesis, abnormally high cholesterol levels ...
membrane. • mitochondrial outer membrane. • endoplasmic reticulum. • mitochondrial inner membrane. • mitochondrial envelope. • ... lipid metabolism. • fatty acid metabolic process. • metabolism. • cardiolipin acyl-chain remodeling. • fatty acid beta- ... and the interaction may play an important role in the estrogen-mediated lipid metabolism in animals and humans.[14] ...
... bein lipid-soluble, muive throu the plasma membranes o target cells (baith cytoplasmic an nuclear) tae act within thair nuclei ... Ither hormones, includin steroid an thyroid hormones, are lipid-soluble; tae allou for their widespread distribution, thir ...
... while the hydrophobic regions are within the phospholipid bilayer of the cell membrane. The cell membrane consists of lipids ... proteins and lipids which are either free flowing or membrane bound, along with different internal compartments known as ... and membrane channels. Inside of the cell are extensive internal sub-cellular membrane-bounded compartments called organelles. ... Viruses lack common characteristics of a living cell, such as membranes, cell organelles, and the ability to reproduce by ...
"Journal of Lipid Research. 29 (5): 587-601. PMID 2900871.. *^ Emorine LJ, Marullo S, Briend-Sutren MM, et al. (September 1989 ... beta-agonist-dependent lipolytic responses and characterization of beta-adrenergic binding sites on human fat cell membranes ...
lipid binding. Cellular component. • cytoplasm. • cyclin-dependent protein kinase 5 holoenzyme complex. • plasma membrane. • ... membrane. Biological process. • positive regulation of protein kinase activity. • regulation of cyclin-dependent protein serine ...
Langerhans cells - LAS - lentivirus - lesion - leukocytes - leukocytosis - leukopenia - leukoplakia - LFT - LIP - lipid - ... mucous membrane - Multicenter AIDS Cohort Study - multi-drug rescue therapy - multiple drug-resistant tuberculosis (MDR-TB) - ...
Others modulate the activity of ion channels that control fluid transport across lung membranes or target surfactant, a ... Cells exposed to these agents demonstrate significant ATP depletion, DNA damage, and lipid peroxidation, followed by death ... Prolonged inflammation and destruction of pneumocytes leads to fibroblastic proliferation, hyaline membrane formation, tracheal ... the endothelium and the basement membrane of the alveolus. In the acute phase of ALI, there is increased permeability of this ...
... aPL bind to the lipids in the test and make it come out positive), although the more specific test for syphilis, FTA-Abs, that ... react against proteins that bind to anionic phospholipids on plasma membranes. Like many autoimmune diseases, it is more common ...
Oligosaccharides (shortish chains), often linked to amino acids or lipids. They play a special role in cell membranes. ...
CSAs have a high binding affinity for such membranes (including Lipid A[1]) and are able to rapidly disrupt the target ... These compounds have a net positive charge that is electrostatically attracted to the negative-charged cell membranes of ... membranes leading to rapid cell death. While CSAs have a mechanism of action that is also seen in antimicrobial peptides, which ...
Envelope: composed of lipids (obtained from the host plasma membrane during the budding process) as well as glycoprotein ... while the ability of the retrovirus to enter the cell via membrane fusion is imparted by the membrane-anchored trans-membrane ... A retrovirus has a membrane containing glycoproteins, which are able to bind to a receptor protein on a host cell. There are ... These pieces are then gathered together and are pinched off of the cell membrane as a new retrovirus (9). ...
Membrane lipids are principally of two types, phospholipids and sterols (generally cholesterol). Both types share the defining ... characteristic of lipids-they dissolve readily in organic solvents-but in addition they both have a region that is attracted to ... Membrane lipids. Membrane lipids are principally of two types, phospholipids and sterols (generally cholesterol). Both types ... This type of lipid bilayer, formed by the self-assembly of lipid molecules, is the basic structure of the cell membrane. It is ...
... it was postulated that lipids in biomembranes are organized in the form of bilayers; the same picture is still... ... Mitochondrial Membrane Lipid Bilayer Spin Label Lipid Vesicle Intact Mitochondrion These keywords were added by machine and not ... Lenaz, G. (1977) in Membrane Proteins and Their Interaction with Lipids (Capaldi, R. A., ed.), p. 47, Marcel Dekker, New York. ... Lenaz G. (1978) Organization and Role of Lipids in Membranes. In: Fleischer S., Hatefi Y., MacLennan D.H., Tzagoloff A. (eds) ...
Psychrophilic bacteria--molecular adaptations of membrane lipids.. Russell NJ1.. Author information. 1. Department of ...
Biological membranes contain a great variety of lipids with different hydrocarbon chains, polar groups, backbone structure ( ... Eibl, H., and Woolley, P., 1979, Electrostatic interactions at charged lipid membranes: Hydrogen bonds in lipid membrane ... Seelig, J., and Seelig, A., 1980, Lipid conformation in model membranes and biological membranes, Q. Rev. Biophys. 13:19.PubMed ... Cullis, P. R., and de Kruijff, B., 1979, Lipid polymorphism and the functional roles of lipids in biological membranes, Biochim ...
Cells produce an array of lipids using tightly controlled enzymes to ensure proper physical properties of membranes. This ... Home Meetings and events 2020 Annual Meeting Biochemistry of lipids and membranes ... Unique aspects of lipid metabolism in the human gut microbiome. Christopher Radka, St. Jude Childrens Research Hospital ... Learn, for example, about gut bacteria as they scavenge fatty acids to build new membranes and chloroplasts as they sense and ...
Lipoproteins and Membranes, Volume 36 - 4th Edition. Print Book & E-Book. ISBN 9780444511386, 9780080930169 ... 1. Functional roles of lipids in membranes (W. Dowhan, M. Bogdanov). 2. Lipid modifications of proteins (N.A. Baumann, A.K. ... Biochemistry of Lipids, Lipoproteins and Membranes, Volume 36 4th Edition. Write a review ... Lipid assembly into cell membranes (D.R. Voelker). 18. Lipoprotein structure (A. Jonas). 19. Assembly and secretion of ...
Lipoproteins and Membranes, Volume 31 - 3rd Edition. Print Book & E-Book. ISBN 9780444823595, 9780080860923 ... Lipid metabolism in plants (K.M. Schmid, J.B. Ohrlogge). 15. Lipid assembley into cell membranes (D.R. Voelker). 16. Assembley ... Chapter 1. Physical properties and functional roles of lipids in membranes (P.R. Cullis, D.B. Fenske, M.J. Hope). 2. Lipid ... Biochemistry of Lipids, Lipoproteins and Membranes, Volume 31 3rd Edition. 0.0 star rating Write a review ...
Membrane lipid homeostasis in bacteria.. Zhang YM1, Rock CO.. Author information. 1. Department of Infectious Diseases, St. ... Bacteria precisely adjust their membrane lipid composition by modifying the types of fatty acids that are produced by the ... Here, the principal genetic and biochemical processes that are responsible for membrane lipid homeostasis in bacteria are ... The ability of bacteria to control the biophysical properties of their membrane phospholipids allows them to thrive in a wide ...
A cytosolic deacylase, APT2, is S-acylated by zDHHC3 and zDHHC7 and is predicted to deform the lipid bilayer to extract acyl ... Deform the membrane, cAPTure the lipid. *Jennifer Greaves. ORCID: ... 1: Kinetic membrane trapping and release of peripheral membrane proteins by dynamic S-acylation.. ... Greaves, J. Deform the membrane, cAPTure the lipid. Nat Chem Biol 17, 371-372 (2021). ...
It used to be thought that the lipid component played a mainly passive role, simply acting as a self-assembled bilayer matrix ... However, it has now become clear that there is a intimate two-way interplay between the lipid and the protein components in ... determining membrane structure, organization and dynamics, and that lipids play many active roles in biological function. ... with particular emphasis on the roles of lipids in these phenomena. As well as discussing new experimental and theoretical ...
Tracking Plasma Membrane Lipids in Living Cells.. Lipid labeling of a phosphoglycero-lipid (phosphoethanolamine, PE) and of a ... S5). The fluorescent lipid analogs were inserted into the plasma membrane of living PtK2 cells by incubation with lipid-BSA- ... for the use of small dye labeled lipids. Nanoscale trapping of fluorescent lipid analogs in the plasma membrane of living cells ... Fast molecular tracking maps nanoscale dynamics of plasma membrane lipids. Steffen J. Sahl, Marcel Leutenegger, Michael Hilbert ...
... which may have applications for studying membrane proteins and may be useful for engineering plants to produce biochemicals, ... Researchers have developed a detailed computational model of the soybean plasma membrane that provides new structural insight ... Similar lipids cluster in soybean cell membrane model Researchers at the University of Maryland use an all-atom lipid force ... Specifically, they used the all-atom CHARRM36 lipid force field to predict how lipids self-assemble into a bilayer membrane, ...
Rather, we show that Mga2 senses the molecular lipid-packing density in a defined region of the membrane. Our findings suggest ... Cells maintain membrane fluidity by regulating lipid saturation, but the molecular mechanisms of this homeoviscous adaptation ... Our data challenge the prevailing hypothesis that membrane fluidity serves as the measured variable for regulating lipid ... and configuration of double bonds in lipid acyl chains, and provide insights into the molecular rules of membrane adaptation. ...
Lipids cannot be broken down into smaller sections and in this we fit probably the most abundant lipid, triglycerol and if you ... I broke lipids down into two main categories. We have hydrolyzable lipids, hydrolyzable, and then not hydrolyzable. Essentially ... theyre another hydrolyzable lipids. So sphingolipid, and you need to talk about sphingolipids because theyre another lipid ... Phospholipids are hydrolyzable lipids, that contain a phosphorus atom. So this phosphorus atom usually comes in a form of a ...
Membrane lipids, membrane proteins, anionic lipids, membrane remodeling, intracellular vesicles, model membrane systems, ... The interplay between lipids and membrane proteins is known to affect membrane protein topology and thus have significant ... Certain membrane proteins involved in lipid synthesis can induce formation of new intracellular membranes in Escherichia coli, ... In this PhD thesis, the influence of lipids on the membrane protein function was studied using three different membrane protein ...
This model is a schematic cross sectional view of a cellular membrane. The first two rows of the lipid bilayer are made of ... The lipid heads farther back in the scene are nurbs to cut down on scene size. The proteins, cross sectioned and whole are also ... polygonal lipids with the generic hydrophilic head and hydrophobic tails. ...
Calditol-linked membrane lipids are required for acid tolerance in Sulfolobus acidocaldarius. Zhirui Zeng, Xiao-Lei Liu, Jeremy ... It is thought that the distinct ether lipid membranes of archaea allow them to thrive in environmental extremes. However, it ... We show that deletion of this protein in Sulfolobus acidocaldarius prevents production of calditol-linked membrane lipids and, ... Archaea have many unique physiological features of which the lipid composition of their cellular membranes is the most striking ...
Although some of these effects involve specific chemical interactions between lipids and protein residues, many can be ... Studies of membrane proteins have revealed a direct link between the lipid environment and the structure and function of some ... Emerging roles for lipids in shaping membrane-protein function Nature. 2009 May 21;459(7245):379-85. doi: 10.1038/nature08147. ... Studies of membrane proteins have revealed a direct link between the lipid environment and the structure and function of some ...
Membrane lipids also form a matrix in which membrane proteins reside. Historically lipids were thought to merely serve a ... lipid bilayer). The three major classes of membrane lipids are phospholipids, glycolipids, and cholesterol. Lipids are ... Non-bilayer forming lipid like monogalactosyl diglyceride (MGDG) predominates the bulk lipids in thylakoid membranes, which ... lipids_by_sucrose?ev=prf_pub YashRoy R.C. (1987) 13-C NMR studies of lipid fatty acyl chains of chloroplast membranes. Indian ...
Distinct chemical families of lipids endow divergent biophysical properties to the membranes in which they reside. Thus, lipid ... "Lipid and Membrane Metabolism" theme will cover phosphoinositides, sphingolipids, phospholipases D and neutral lipids. The ... Lipid and Membrane Metabolism. Session: Current Topics in Phosphoinositide Biology and Signaling. • Ptdlns-4-kinase Regulation ... The 2011 American Society for Biochemistry and Molecular Biology annual meeting "Lipid and Membrane Metabolism" theme focuses ...
Membrane lipids are small molecules and they have both hydrophilic and hydrophobic moieties. The membrane lipids form closed ... Membranes are fluid and lipid and protein molecules can freely diffuse into the plane of the membrane but do not rotate across ... The membranes are two dimensional planes of oriented proteins and lipids. Membranes are not static sheets of molecules locked ... The mass ratio of lipids to proteins can range anywhere from 1:4 to 4:1. Although most membranes are made mostly of lipids and ...
... there is no accepted explanation for its formation from cellular membranes. A subsequent membrane-wrapping step involving ... These wrapped virions traverse the cytoplasm on microtubules; the outermost membrane is lost during exocytosis, the middle one ... Although a proposal that the initial membrane arises de novo has not been substantiated, ... is lost just prior to cell entry, and the remaining membrane fuses with the cell to allow the virus core to enter the cytoplasm ...
Motivated by published experiments on curvature-modulated phase separation in lipid membranes, we formulate a mathematical ... and lipid phases beyond those used in the experiments. In addition, we demonstrate the possibility for curvature-modulated ... lipids, and cholesterols, leads to the formation of aggregates or domains that are rich in specific constituents. This process ... 54] used a double membrane system to decouple the main membrane from the underlying substrate: a "supporting" membrane of ...
Lipid is an important constituent of cell membrane. Membrane lipid composition of spermatozoa has been correlated to different ... Its plasma membrane is also different from most other cell membranes in lipid composition. It contains high amount of ... The definite lipid pattern of ejaculated spermatozoa is reached only after epididymal maturation. Plasma membrane lipids of the ... "Lipid heterogeneity and membrane fluidity in a highly polarized cell, the mammalian spermatozoon," The Journal of Membrane ...
Dietary Supplement: NTFactor Lipids® Membrane Lipid Replacement with NTFactor Lipids wafers. Other Name: Patented Energy wafers ... Clinical uses of Membrane Lipid Replacement supplements in restoring membrane function and reducing fatigue in chronic diseases ... Membrane Lipid Replacement: clinical studies using a natural medicine approach to restoring membrane function and improving ... Membrane Lipid Replacement in Fibromyalgia. The safety and scientific validity of this study is the responsibility of the study ...
Sites of lipid degradation are intralysosomal membranes that are formed in endosomes, where the lipid composition is adjusted ... The constitutive degradation of membrane components takes place in the acidic compartments of a cell, the endosomes and ... Sites of lipid degradation are intralysosomal membranes that are formed in endosomes, where the lipid composition is adjusted ... Lysosomal degradation of membrane lipids FEBS Lett. 2010 May 3;584(9):1700-12. doi: 10.1016/j.febslet.2009.10.021. Epub 2009 ...
... similar experiments may be applied to more complex lipid-membrane systems, including lipid/peptide, lipid/protein or lipid/DNA ... As the basic building blocks of biological membranes, the structure and physical properties of lipid bilayers are of great ... according to which the entropic forces generated by the fluctuating membranes may lead to an unbinding of the membranes from ... Apart from the predominant role in the organisation of the biological cells, lipid bilayers can be expected to become a key ...
Strikingly, the sensor can resolve the interaction of lipid membranes with a toxic pore-forming peptide such as melittin, both ... In particular, the study shows that the sensor can spectroscopically resolve the interaction of biomimetic lipid membranes with ... Resolving molecule information in dynamic lipid membrane with metasurfaces. Ecole Polytechnique Fédérale de Lausanne ... "Resolving molecule-specific information in dynamic lipid membrane processes with multi-resonant infrared metasurfaces", Nature ...
... are surrounded by lipid-bilayer membranes that compartmentalize biochemical reactions and pathways. Membrane-embedded proteins ... Traditionally, membrane proteins were pictured as floating around quite independently of the surrounding lipids, yet when this ... State-of-the-art mass spectrometry reveals how many specific lipids are bound to membrane proteins. ... State-of-the-art mass spectrometry reveals how many specific lipids are bound to membrane proteins. ...
Locally induced lipid phase transitions reveal how protein-free lipid membranes exhibit transient and localized permeation. ... Physical and chemical modifications of lipid structures to inhibit permeation of free radicals in a supported lipid. membrane ... Interactions of PEO-PPO-PEO block copolymers with lipid membranes: a computational and experimental study linking membrane ... From the themed collection: Interaction of nano-objects with lipid membranes The article was first published on 07 Aug 2013. ...
  • define how a ubiquitously expressed APT, acyl protein thioesterase 2 (APT2), interacts with lipid bilayers and releases bound fatty acids from S-acylated substrates, demystifying the molecular mechanisms of how this class of enzymes mediate cellular S-acylation dynamics 4 . (
  • Archaeal ether-linked isoprenoidal membranes can occur as bilayers or monolayers, possess diverse polar head groups, and a multiplicity of ring structures in the isoprenoidal cores. (
  • However, in combination with other lipids and carotenoids/chlorophylls of thylakoid membranes, they too conform together as lipid bilayers. (
  • The bacteria cell wall, like most lipid bilayers, is porous and semipermeable. (
  • As the basic building blocks of biological membranes, the structure and physical properties of lipid bilayers are of great interest. (
  • Apart from the predominant role in the organisation of the biological cells, lipid bilayers can be expected to become a key component of novel biomolecular materials. (
  • In particular, solid-supported lipid bilayers may provide a way to biofunctionalise solid state and semiconductor surfaces, providing a compatible interface between the inorganic and biomolecular world [1]. (
  • To investigate the thermal stability and fundamental fluctuation properties of solid supported lipid bilayers, we have carried out a series of specular and nonspecular X-ray reflectivity measurements using 20 keV synchrotron beams to probe phospholipid samples fully immersed in water, see Figure 26 . (
  • 2 ) report mass spectrometry of intact integral membrane protein complexes solubilized from bilayers. (
  • Cholesterol and oxidized lipid species co-localize in phospholipid bilayers owing to their complementary shape factors. (
  • Tethered lipid bilayers represent one of the most promising classes of model membranes and are based on the immobilization of a planar lipid bilayer on a solid support that enables characterization by a wide range of surface-sensitive analytical techniques. (
  • Moreover, as the result of molecular engineering inspired by biology, tethered bilayers are increasingly able to mimic fundamental properties of natural cell membranes, including fluidity, electrical sealing and hosting transmembrane proteins. (
  • Taken together, the capabilities of tethered lipid bilayers have opened the door to biotechnology applications in healthcare, environmental monitoring and energy storage. (
  • By drawing connections between these strategies and promising research results, future opportunities for tethered lipid bilayers within the biotechnology field are discussed. (
  • Fig. 88: (a) Typical diffuse scattering distribution of multilamellar lipid bilayers (DMPC, fluid phase). (
  • Liposomes, lipid bilayers and model membranes. (
  • This Research Topic focuses on the biointerfacial science of supported lipid bilayers, with a nano-perspective. (
  • These functionalized lipids, along with two other lipids having hydroxyl (PSOH) and iminodiacetic acid (PSIDA) headgroups, were incorporated into bilayers of distearylphosphatidylcholine (DSPC) producing materials that exhibited an excellent range of sensitivity for the metal ions at low pH. (
  • In addition to optical sensing, the bilayers also can undergo restructuring of the membrane architecture. (
  • However, for the PSBiPy/DSPC membranes extraordinary square-shaped assemblies of planar bilayers formed in the presence of 100 µM Cu2+. (
  • By using the two complementary cyclodextrins (methyl-beta and hydroxypropyl-alpha), I assay the accessibility of both cholesterol and phospholipids for removal from lipid bilayers. (
  • We describe a system that provides a rapid and simple way of forming suspended lipid bilayers within a microfluidic platform from an aqueous droplet. (
  • The formation of the BLM depends solely on the device geometry and leads to spontaneous formation of lipid bilayers simply by dispensing droplets of buffer. (
  • Here we use neutron spin echo spectroscopy (NSE) to provide unique insights into these elusive dynamics and measure membrane mechanical properties by probing both bending and thickness fluctuations in model lipid bilayers. (
  • For example, the thickness fluctuation amplitude is enhanced in the fluid phase of mixed lipid bilayers, reaching approximately 20{\%} of the bilayer thickness. (
  • Combining these experimental results with deformation free energy calculations suggests the mixed bilayers are more compressible than single component bilayers and provides new insights into the role of lipid diversity in controlling the rich dynamics of biomembranes. (
  • As compared to the free-standing lipid bilayers, there are fewer simulation studies addressing the systems of supported lipid membranes. (
  • In this review, we give an account of the state of the art of methods and applications of the simulations of supported lipid bilayers, interfacial membranes at the air/water interface and on solid surfaces. (
  • We summarize new data supporting the diffusion hypothesis in simple lipid bilayers and in plasma membranes of cells. (
  • In this work, we study the interaction of a well-known photosensitizer, MePha, with models of biological membrane (Langmuir monolayers and Langmuir-Schaeffer planar bilayers) based on one of the most important natural lipid, POPC, for the subsequent investigation of photodestruction processes in a context of photodynamic therapy treatment. (
  • These quasi-1D lipid bilayers are ideal for testing and understanding fundamental concepts about the roles of dimensionality and size on physical properties of membranes from energy transfer to lipid packing. (
  • The intermolecular packing of a beta-hairpin antimicrobial peptide, PG-1, in lipid bilayers is determined using solid-state NMR distance measurements. (
  • Membrane lipids are principally of two types, phospholipids and sterols (generally cholesterol ). (
  • In a water medium, the phospholipids of the two sheets align so that their water-repellent, lipid-soluble tails are turned and loosely bonded to the tails of the molecules on the other sheet. (
  • The ability of bacteria to control the biophysical properties of their membrane phospholipids allows them to thrive in a wide range of physical environments. (
  • Bacteria precisely adjust their membrane lipid composition by modifying the types of fatty acids that are produced by the biosynthetic pathway and altering the structures of pre-existing phospholipids. (
  • The recycling of phospholipids that are used as intermediates in the biosynthesis of other major membrane components is also crucial to bilayer stability in dividing cells. (
  • Both the bacteria and higher-level organisms have a double layer cell membrane composed of phospholipids, where the hydrophobic tails of each layer point toward the middle of the membrane and hydrophilic heads face the outside and inside of the cell. (
  • Phospholipids are hydrolyzable lipids, that contain a phosphorus atom. (
  • The three major classes of membrane lipids are phospholipids, glycolipids, and cholesterol. (
  • The heads of phospholipids are phosphorylated and they consist of either: Glycerol (and hence the name phosphoglycerides given to this group of lipids), or Sphingosine (e.g. sphingomyelin and ceramide). (
  • Phospholipids are the most representative lipid fraction of the sperm cell membranes, of which phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin are the major components [ 6 ]. (
  • Lipid peroxidation was assessed in fresh, untreated erythrocytes by quantitating thiobarbituric acid reactivity and an adduct of phospholipids and malonyldialdehyde (MDA), an end product of lipid peroxidation, with thin-layer chromatography of lipid extract of diabetic erythrocytes. (
  • IMAGE: This illustration shows the production of various cardiolipins and phospholipids by incorporation of environmental compounds as lipid head group. (
  • Cells of all life forms are surrounded by a membrane that is made of phospholipids. (
  • The phospholipids that are most abundant in cell membranes contain a hydrophilic head to which two hydrophobic tails are connected. (
  • Our group at the University of Groningen focuses on cell membrane growth, based on the enzymatic production of new phospholipids from basic building blocks. (
  • This is useful because head groups in membrane phospholipids affect the overall properties of the membrane and the function of enzymes that are incorporated in it. (
  • Depending on the environment, the enzyme can switch the production towards different phospholipids and in doing so, alter the functionality of the membrane. (
  • The lipid molecules of membranes also known as phospholipids are com. (
  • The lipid molecules of membranes, also known as phospholipids, are composed of two elements: A hydrophilic head and two long-chain fatty acids. (
  • They experimented with synthetic peptides, which transport phospholipids through the membrane. (
  • The peptides span both layers of the membrane and are able to bind to individual phospholipids. (
  • The new phospholipids use this opportunity to slip through the barrier of the first lipid layer and flip to the second layer of the membrane. (
  • As briefly stated in a previous section on the fluid mosaic model of biological membranes, proteins and phospholipids diffuse both laterally and, to a lesser extent transversely, through the entire span of a membrane. (
  • The speeds for membrane proteins vary a great deal from nearly immobile to nearly as fast as a phospholipids. (
  • Cell membranes are composed of a bilayer of phospholipids that have hydrophilic ('water-loving') heads (spherical) and hydrophobic ('water-hating') tails. (
  • In previous studies on the causes of imbibitional leakage in dry polien we have presented data which suggest that the leakage is due to a gel to liquid crystalline phase transition in membrane phospholipids during the rehydration event. (
  • A supplemented phase diagram for the hydration dependent transition temperature of membrane phospholipids in pollen is presented. (
  • Lipids including inositol phospholipids, cholesterol, sphingolipids and ceramides play important roles in signalling cellular responses to stress and specific stimuli such as growth factors, cytokines and neurotransmitters. (
  • Amphiphilic lipids, lamellar phospholipids with cholesterol, and bovine spinal cord (BSC) specimens were examined along with nonlipid systems. (
  • The Biosynthesis and Evolution of Archaeal Membranes and Ether Phospholipids. (
  • Cell membranes feature complex intermolecular interactions between phospholipids and sterols. (
  • After aggregation, we find spontaneous uptake of phospholipids from anionic model membranes into the amyloid fibrils. (
  • Phospholipid quantification, polarization transfer solid-state NMR and cryo-TEM together reveal co-aggregation of phospholipids and α-synuclein in a saturable manner with a strong dependence on lipid composition. (
  • At low lipid to protein ratios, there is a close association of phospholipids to the fibril structure, which is apparent from reduced phospholipid mobility and morphological changes in fibril bundling. (
  • Oxidized phospholipids occur naturally in conditions of oxidative stress and have been suggested to play an important role in a number of pathological conditions due to their effects on a lipid membrane acyl chain orientation, ordering, and permeability. (
  • It is generally thought that the saturated acyl chains of raft sphingolipids and phospholipids exhibit tight packing in a manner analogous to the liquid-ordered domains observed in model membranes, and that this may account for their resistance to solubilization by cold nonionic detergents (e.g. (
  • Biological membranes contain a great variety of lipids with different hydrocarbon chains, polar groups, backbone structure (glycerol or sphin-gosine), type of chemical linkage (ester or ether) of the hydrocarbon chains to glycerol, as well as other less common variations. (
  • this is one of a select group of books in the lipid field that I would expect to find in every biological library. (
  • However, it has now become clear that there is a intimate two-way interplay between the lipid and the protein components in determining membrane structure, organization and dynamics, and that lipids play many active roles in biological function. (
  • Voiceover] Alright so in a previous video I introduced a class of biological molecules called lipids. (
  • I want to continue talking about these hydrolyzable lipids but the other ones that I think are important instead of kind of having a predominant energy storage function, they have a structural function in our cells and kind of in the biological role, so a structural function. (
  • Because lipid signaling pathways interface with highly interdigitated networks of biological processes, diverse territories of intracellular lipid metabolism and trafficking need to be tightly coordinated. (
  • The 2011 American Society for Biochemistry and Molecular Biology annual meeting "Lipid and Membrane Metabolism" theme focuses on new progress regarding how the metabolism, trafficking, organization and biological functions of major lipid classes are coordinated. (
  • The biological lipid bilayer membrane, or in short "biomembrane," is a fundamental building block of the cell. (
  • Detecting biomolecules, such as lipids, proteins, and nucleic acids and their interactions in heterogeneous biological samples is crucial for understanding a multitude of biological mechanisms in health and disease. (
  • The importance of cell membranes in biological systems has prompted the development of model membrane platforms that recapitulate fundamental aspects of membrane biology, especially the lipid bilayer environment. (
  • Lipid membranes are important model systems for biological membranes. (
  • Amphiphilic Janus particles self-assemble into complex metastructures, but little is known about how their assembly might be modified by weak interactions with a nearby biological membrane surface. (
  • ETH Zurich researchers have been able to show why biological cells can take on such an astonishing variety of shapes: it has to do with how the number and strength of local forces acting on the cell membrane from within. (
  • Spiny projections, long flagella or fibres, misshapen bulges: biological cells can form almost any complex membrane structure. (
  • Membrane pores can significantly alter not only the permeation dynamics of biological membranes but also their elasticity. (
  • All biological membranes contain lipids that prefer to adopt a non-bilayer phase. (
  • Lipids are not only essential building blocks of biological membranes, but they also emerge as bona fide regulators of cellular and developmental processes. (
  • These experiments are helping us better understand both the structure of phospholipid membranes and the potential biological effects of exposure to nanoparticles found in our normal, everyday environment," Granick said. (
  • These patterns of change in membrane lipid composition are in a direction consistent with thermal compensation of membrane function and suggest that rapid adjustments in the lipid composition of biological membranes may stabilize membrane structure against substantial diurnal fluctuations in temperature. (
  • The fusion of lipid membranes is central to biological functions like inter-cellular transport and signaling and is coordinated by proteins of the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) superfamily. (
  • The diffusion of lipids and proteins within membranes are crucial to a variety of biological processes. (
  • Lipid membranes are of great importance for many biological systems and biotechnological applications. (
  • Nevertheless, these have significantly enhanced our understanding of the behavior of lipid layers employed in applications spanning from biosensors to drug delivery and for biological processes such as the breathing cycle of lung surfactants. (
  • which can damage biological molecules, including lipids, proteins and DNA ( Halliwell and Gutteridge, 1999 ). (
  • Temperature acclimation/adaptation typically results in restructuring of biological membranes and various metabolic changes in ectotherms, and these physiological responses should impact the susceptibility of biological membranes to LPO ( Crockett, 2008 ). (
  • Progressively refined imaging techniques continue to support the existence of lateral protein/lipid heterogeneities in biological membranes ( 2 , 3 ), but the precise nature, size, and malleability of these microdomains remain a matter of debate. (
  • Although it is difficult to place a lower limit on their size in the resting state, and evidence indeed exists for "lipid shells" surrounding individual proteins in biological membranes ( 2 ), rafts can also be driven to coalesce into more stable, micrometer-range domains through lipid-lipid, protein-lipid, and protein-protein interactions. (
  • The diffusion behavior of biological components in cellular membranes is vital to the function of cells. (
  • A monotopic membrane protein, monoglucosyldiacylglyecerol synthase (MGS) from Acholeplasma laidlawii is known to induce intracellular vesicles when expressed in Escherichia coli . (
  • Strikingly, the sensor can resolve the interaction of lipid membranes with a toxic pore-forming peptide such as melittin, both in supported membranes and surface-tethered vesicles loaded with neurotransmitter molecules. (
  • We created an experimental system in which Janus particles are allowed to self-assemble in the same medium where zwitterionic lipids form giant unilamellar vesicles (GUVs). (
  • Researchers have long been using large vesicles surrounded by a double lipid membrane to investigate such processes. (
  • Both approaches show that the particles first collide with the membrane of the vesicles at random points - and in doing so trigger effects similar to those of Listeria in a real cell. (
  • In fact, the more particles the vesicles contained, the less the membrane reacted to the point forces exerted by the particles. (
  • In this paper, we present a detailed experimental analysis of the active shape fluctuations that appear in highly permeable lipid vesicles with large macromolecular pores inserted in the lipid membrane, which are a consequence of transport permeability events occurred in an osmotic gradient. (
  • Finally, a bio-nano-technology outlook of the proposed synthetic concept is given on the context of prospective uses as active membrane DNA-pores exploitable in gen-delivery applications based on lipid vesicles. (
  • To study the role of lipid composition in degranulation, large unilamellar vesicles (LUVs) of increasing complexity in lipid compositions were constructed and tested for Ca 2+ -mediated lipid and contents mixing. (
  • Membrane Vesicles, Nanopods and Nanotubes of Archaea. (
  • Outer Membrane Vesicles of Bacteria. (
  • In this work, we use the popular Helfrich-Cahn-Hilliard phase field model for two-component lipid bilayer vesicles to systematically study phase transitions in lipid vesicles. (
  • At higher lipid to protein ratios, additional vesicles adsorb along the fibrils. (
  • The present study examined calcium phosphate precipitation in aqueous suspensions of artificial liposomes which closely resembled matrix vesicles (MV) in membrane lipid composition. (
  • One notable example is the dynamics of proteins and lipids in cellular membranes and their organization into nanodomains, so-called "lipid rafts" ( 8 - 12 ). (
  • This proposal investigates the hypothesis that coincidence detection of proteins and lipids constitutes a major mechanism for specific recruitment of proteins to intracellular membranes in order to control cellular membrane dynamics. (
  • Our strong expertise enables us to study phenomena based on lipid-protein interactions at different levels - from the organ and cell systems down to minimally synthetic systems in which we can control both proteins and lipids, for example to observe the allosteric effects of certain lipids on basic receptors such as the EGF receptor (Coskun et al. (
  • To get insight into the significance of the mobility (dynamics) of proteins and lipids, I refer to the chapter "Role of Lipids in the Dynamics of Thylakoid membrane" (title of the book is Lipids in Photosynthesis ) written by C. W. Mullineaux and H. Kirchhoff2. (
  • The authors describe how important the mobility of proteins and lipids is in photosynthesis, and some examples are plastoquinol diffusion during electron transport, LHCII mobility during state transitions and membrane biogenesis, and in turnover & repair of thylakoid membrane proteins. (
  • Edidin discusses the questions surrounding lipid rafts, membrane microdomains that have been biochemically defined but are difficult to visualize in vivo. (
  • He also discusses whether experiments showing correlation of changes in plasma membrane cholesterol with differentiation and the formation of adherens junctions in endothelial cells are consistent with a model in which lipid rafts influence the regulation of these processes. (
  • This book presents an overview of membrane organization and lipid rafts in the cell and artificial membranes. (
  • The topics analyzed in this book cover a broad spectrum of functions played by lipid rafts in membrane organization within the cell and artificial membranes, and presents new information in this area of research. (
  • Lipid Rafts. (
  • One of the most controversial concepts in biophysics is the hypothesis of the so-called lipid rafts: areas of high concentrations of cholesterol and glycosphingolipids in membranes. (
  • These lipid rafts, also known as lipid microdomains, are areas of the cell membrane in which lipids and cholesterol accumulate and play an important role in cell function. (
  • Currently, the presence of lipid rafts in live cells is only a hypothesis because although various laboratory studies have attempted to simulate them by mixing two types of lipid and cholesterol, none has managed to detect them or determine whether they really exist, how they are formed and how they function in live cells. (
  • It is suspected that lipid rafts are also responsible for the onset of diseases such as Creutzfeldt-Jakob or AIDS, the pathogens of which pass through them to enter the cells. (
  • And after a series of simulations they confirmed that these domains-the lipid rafts-are highly dynamic, they form and then disappear only to form again and they exist for approximately 10 nanoseconds. (
  • This study may serve to develop new crucial approaches for researching lipid rafts, so the development of some diseases and cell processes will also be better understood. (
  • Caveolae are invaginations of the plasma membrane that may arise from so called rafts in the presence of the structural protein caveolin. (
  • As a comparison we also isolated a detergent-insoluble fraction of the plasma membrane, utilizing the detergent insolubility of caveolae and rafts. (
  • Lipid rafts and caveolae play a pivotal role in organization of signaling by TLR4 and several other immune receptors. (
  • In this review, using TLR signaling in the macrophage as a central focus, we discuss emerging evidence that environmental and genetic perturbations of membrane lipid regulate protein signaling, illustrate how homeostatic flow of cholesterol and other lipids through rafts regulates the innate immune response, and highlight recent attempts to harness these insights toward therapeutic development. (
  • However, as detergent can itself induce the formation of domains in membranes ( 6 ), rafts should not be equated with "detergent-resistant membranes" (DRMs), nor can identification of a protein in DRMs be taken as sufficient evidence for assigning raft localization in vivo. (
  • Although good evidence supports the coexistence within cell membranes of heterogeneous populations of lipid rafts, isolation of DRMs of discrete composition with the use of different detergents should not be considered as evidence for discrete raft domains in vivo. (
  • Lipid rafts are liquid-ordered domains that are more tightly packed than the surrounding non-raft phase of the bilayer. (
  • Lipid rafts are proposed to be highly dynamic, submicroscopic assemblies that float freely within the liquid disordered membrane bilayer and some proteins preferentially partition into the ordered raft domains. (
  • We asked the question whether lipid rafts do exist in prostasomes and, if so, which proteins might be associated with them. (
  • Prostasomes of density range 1.13-1.19g/mL were subjected to density gradient ultracentrifugation in sucrose fabricated by phosphate buffered saline (PBS) containing 1% Triton X-100 with capacity for banding at 1.10g/mL, i.e. the classical density of lipid rafts. (
  • Prepared prostasomal lipid rafts (by gradient ultracentrifugation) were analyzed by mass spectrometry and electron microscopy. (
  • This is the first comprehensive LC-MS/MS profiling of proteins in lipid rafts derived from exosomes. (
  • In Paper I, we show that the prostasomal bilayered membrane consists of lipid rafts, clusters that holds cholesterol, sphingolipids and gives receptors a rigid platform upon which to work. (
  • We compare the proteomic content of prostasome lipid rafts with the entire prostasome membrane in the search for a specific biomarker. (
  • This suggests that lipids must have some functions more specialized than maintenance of a bilayer to enclose the cell contents and of proper fluidity to allow dynamic protein function. (
  • Depending on their concentration, sterol molecules can enhance membrane fluidity or increase its rigidity. (
  • Cells maintain membrane fluidity by regulating lipid saturation, but the molecular mechanisms of this homeoviscous adaptation remain poorly understood. (
  • Our data challenge the prevailing hypothesis that membrane fluidity serves as the measured variable for regulating lipid saturation. (
  • Membrane fluidity determines how easily lipids and proteins can diffuse laterally in the plane of the membrane. (
  • How do cells, e.g., balance the need for maintaining membrane fluidity with the need to maintain organelle-specific lateral pressure profiles 20 ? (
  • In particular, PUFA are known to contribute to membrane fluidity and flexibility [ 3 - 5 ]. (
  • Membrane lipid composition has been related to their specific functions, because it promotes the creation of microdomains with different fluidity, fusogenicity, and permeability characteristics [ 2 ], required for reaching and fusing with the oocyte. (
  • The tails are fatty acid chains, and their length and properties determine the fluidity of the cell membrane. (
  • When animals hibernate in the winter at a reduced temperature, the type and amount of phosopholipids adjust to maintain the fluidity of the membrane. (
  • The lipids of cellular membranes not only serve roles in controlling the structure and fluidity of the membrane, but are increasingly recognized for their roles as signalling molecules and modifiers of membrane protein function. (
  • Lipid-protein Interactions Determining Membrane Fluidity in Prokaryotes and Eukaryotes. (
  • From a mathematical point-of-view, a particularly troubling aspect of lipid membrane behavior is its fluidity. (
  • The aim of this study was to assess the effect of laser radiation emitted by the MLS M1 system (Multiwave Locked System) at two wavelengths (808 nm continuous and 905 nm pulsed) on the stability and fluidity of liposomes with a lipid composition similar to that of human erythrocyte membrane or made of phosphatidylocholine. (
  • Since MLS M1 laser radiation, depending on the parameters used, affects fluidity and stability of liposomes with the lipid content similar to erythrocyte membrane, it may also cause structural and functional changes in cell membranes. (
  • i.e., containing both a lipid-soluble and a water-soluble region) is basic to the role of lipids as building blocks of cellular membranes. (
  • Class I sensors interrogate surface properties of cellular membranes, such as the surface charge and molecular packing density as reported for amphipathic lipid-packing sensor (ALPS) motif-containing proteins and other amphipathic helix-containing proteins 31 . (
  • This model is a schematic cross sectional view of a cellular membrane. (
  • Archaea have many unique physiological features of which the lipid composition of their cellular membranes is the most striking. (
  • Phosphoinositides are essential signaling lipids that modulate a diverse set of cellular processes. (
  • Sphingolipids facilitate the formation of membrane microdomains and act as signaling molecules that regulate a myriad of cellular processes. (
  • Although a proposal that the initial membrane arises de novo has not been substantiated, there is no accepted explanation for its formation from cellular membranes. (
  • In a typical procedure, a specific portion of a cellular membrane is first tagged with a fluorescent chromophore. (
  • The overarching topic of my research group is membrane biochemistry of cellular signalling. (
  • The ability of cell-penetrating peptides to cross plasma membranes has been explored for various applications, including the delivery of bioactive molecules to inhibit disease-causing cellular processes. (
  • Co-aggregation of lipids and amyloid proteins in amyloid aggregates, and the related extraction of lipids from cellular membranes, can influence structure and function in both the membrane and the formed amyloid deposit. (
  • Membrane polar lipids did not contain significantly more saturated fatty acids than cellular polar lipids. (
  • Differences in the proportion of some fatty acids in membrane and cellular glycerides were noted. (
  • Consequently, many cellular processes such as endocytosis, migration and morphogenesis rely on proteins that bind directly to membranes and sculpt them into desired shapes. (
  • In a new study published in Cell Reports ( 'Membrane-Sculpting BAR Domains Generate Stable Lipid Microdomains' ), Hongxia Zhao working in the Lappalainen laboratory discovered that all BAR domain proteins induce strong clustering of phosphoinositides, which are important lipids involved in regulating protein functions and cellular signalling. (
  • These extremely stable protein-lipid scaffolds may contribute to diverse cellular processes by generating lipid phase boundaries at the tips of the BAR domain scaffolds. (
  • Cholesterol and sphingolipids represent important lipid components of eukaryotic membranes and play a crucial role in a variety of cellular functions. (
  • The alterations found in the lipid composition of liver nodules are significant and have functional implications in many cellular processes of proposed importance for the carcinogenic process, i.e. , protein glycosylation cholesterogenesis, regulation of the mevalonate pathway, cellular oxidation-reduction state, and resistance to oxidative stress. (
  • article{64f64a1e-359f-47da-855a-583a5890576b, abstract = {Amyloid deposits from several human diseases have been found to contain membrane lipids. (
  • Some ROS can initiate lipid peroxidation (LPO), a self-propagating process in which a peroxyl radical is formed when a ROS has sufficient reactivity to abstract a hydrogen atom from an intact lipid ( Halliwell and Gutteridge, 1999 ). (
  • Role of Lipids in the Eukaryotic Secretory Pathway. (
  • Since their proposal, the question of the existence and functional role of such cholesterol-mediated lipid assemblies has caused much controversy ( 13 - 16 ). (
  • Recently, stimulated-emission-depletion (STED) nanoscopy ( 21 , 22 ), delivering subdiffraction resolution in live cells, provided direct evidence that certain lipids are transiently trapped in cholesterol-assisted molecular complexes ( 23 , 24 ). (
  • The lipid content of whole sperm decreases during epididymal maturation in boar, bull, ram, and rat [ 19 - 26 ], and the cholesterol content decreases in ram, rat, and hamster sperm [ 27 - 29 ]. (
  • Cholesterol is sorted out of the inner membranes, their content in bis(monoacylglycero)phosphate increases, and, most likely, sphingomyelin is degraded to ceramide. (
  • The combined shape factor for a cholesterol-oxidized lipid product is ∼1. (
  • The functions of cholesterol and membrane microdomains in transmembrane signaling remain controversial. (
  • The addition of cholesterol significantly lowered the Ca 2+ threshold for contents mixing and increased the maximum rates of both lipid and contents mixing in a dose-dependent manner. (
  • Membrane remodeling, which occurs in neutrophil plasma membranes upon stimulation, was simulated by incorporating low levels of phosphatidic acid (PA) or a diacylglycerol (DAG) into complex LUVs containing 50% cholesterol. (
  • These results suggest that the rate of degranulation may be increased by a rise in the cholesterol level of either the inner face of the plasma membrane or the outer face of the granule membrane. (
  • In this dissertation, I discuss how the accessibility (a measure of chemical activity) of cholesterol in a lipid bilayer varies as a function of bilayer composition. (
  • Cholesterol is crucial to the formation of the cell membranes of mammals and is part of many life processes. (
  • In this research, the scientists have carried out an experiment with a lipid membrane very similar to human cells in terms of the size scale, and the dimension and composition of the cholesterol. (
  • The team also made another important discovery about the role of cholesterol in membranes: cholesterol may be responsible for destabilizing the membranes and helping nanometric-sized objects to enter the cells . (
  • We found that when there are high concentrations of cholesterol, nanotubes can spontaneously leave the membrane in a question of milliseconds. (
  • But if the membrane has no cholesterol, they remain trapped inside. (
  • Yachong Guo et al, Unexpected Cholesterol-Induced Destabilization of Lipid Membranes near Transmembrane Carbon Nanotubes, Physical Review Letters (2020). (
  • 2. The molar ratio of cholesterol to phospholipid was greatest in the membranes and closely resembled that reported for myelin. (
  • 3. Unesterified cholesterol was the major neutral lipid. (
  • The cholesterol:polar lipid (phospholipid+glycolipid) ratio was about 1:3 for the microvillus membrane. (
  • Since GPCRs are integral membrane proteins, interaction of membrane lipids such as cholesterol and sphingolipids with GPCRs constitutes an emerging area of research in contemporary biology. (
  • We report that the FAAH dimer is stabilized by the lipid bilayer and shows a higher membrane-binding affinity and enzymatic activity within membranes containing both cholesterol and the natural FAAH substrate AEA (anandamide). (
  • Membrane lipid composition affects eCB uptake and signalling, and cholesterol has been demonstrated to be a key determinant of this regulation [ 6 ]. (
  • In many cell types, increasing or decreasing membrane cholesterol content enhances or inhibits AEA uptake respectively [ 6 , 7 ]. (
  • Recently, it has been proposed that cholesterol modulates AEA transport across the membrane, leading to increased AEA hydrolysis by FAAH [ 11 ]. (
  • Caveolae were strongly enriched in cholesterol and sphingomyelin, the concentration was 3.5 and 2.8-fold, respectively, higher in the caveolar membrane than in the surrounding plasma membrane. (
  • Simple interventions upon membrane lipid, such as changes in cholesterol loading or crosslinking of raft lipids, are sufficient to induce micrometer-scale reordering of membranes and their protein cargo with consequent signal transduction. (
  • Since the inception of the lipid raft hypothesis in 1997 ( 1 ), a profusion of studies have reported roles for these cholesterol-enriched membrane microdomains in organization of cell signaling. (
  • The case will be made that dynamic remodeling of raft lipid is not only necessary in many signaling cascades, but that primary perturbations of raft lipid (e.g., cholesterol loading or unloading, raft coalescence) can also be sufficient initiating events to trigger protein signaling. (
  • 200 nm), cholesterol- and sphingolipid-enriched membrane microdomains, likely present in all eukaryotic cells, that compartmentalize select signaling and functional events. (
  • Most research on modeling plasma membranes has focused on single-celled microbes, such as E. coli or yeast, or on certain organs in model mammalian species. (
  • Plant plasma membranes haven't been studied before at the all-atom computation level," said Jeffery Klauda, associate professor of chemical and biomolecular engineering at the University of Maryland and lead investigator of the work. (
  • These plasma membranes contain proteins that are involved in controlling what goes in and out of the cell, so to look at those proteins that reside in the membrane, we need to understand what the membrane is. (
  • Complex" LUVs of PC∶PE∶SM∶PI∶PS (24∶27∶20∶16∶13, designed to emulate neutrophil plasma membranes) also showed very low rates of both lipid mixing and contents mixing. (
  • In contrast, the molecular species composition of muscle microsomes (a mixture of endoplasmic reticulum and plasma membranes) changed markedly from the cool of the morning to the heat of the afternoon in both species. (
  • 1. Rat intestinal microvillus plasma membranes were prepared from previously isolated brush borders and the lipid composition was analysed. (
  • 5. In contrast with other plasma membranes in the rat, the polar lipids of the microvillus membrane were rich in glycolipid. (
  • (3-6) The importance of hydrophobic interactions between lipids and proteins was stressed by Green and Fleischer (7) and subsequently confirmed in reconstitution studies of the inner mitochondrial membrane by Lenaz et al . (
  • Studies of the physical properties and phase behavior of lipids have shown that lipids can also play dynamic roles and can respond to changes in their environment by undergoing phase transitions, alterations in lipid- lipid and lipid-protein interactions, and by release or uptake of cations or protons. (
  • The researchers used molecular dynamics computer simulations to simulate the structure and dynamics of the complex lipid membrane, which used Newton's equations of motion to understand how molecules move in response to forces generated by atomic interactions. (
  • Although some of these effects involve specific chemical interactions between lipids and protein residues, many can be understood in terms of protein-induced perturbations to the membrane shape. (
  • The results may be put in perspective to the relevant microscopic interactions and also be compared to current theories of membrane fluctuations and defects [3]. (
  • The present review assembles investigations on lipid-polymer-nanoparticle interaction providing a more thorough understanding of these complex interactions and their effects on membrane properties, aiming at a deeper understanding of these hybrid-vesicular systems. (
  • Their shape, composition and phase synergistically regulate biophysical membrane properties, membrane protein function and lipid-protein interactions. (
  • The combined experimental and simulation results show that Janus particles concentrate on the lipid membranes due to weak particle-lipid attraction, whereas the biased orientation of particles is driven predominantly by inter-particle interactions. (
  • The mechanical response of such lipid membranes is fascinating, as at the same time it provides a stable shell regulating the interactions of a cell with the environment, but on the other hand, it is quite deformable. (
  • Supported lipid membranes are an important biomimetic platform to study the structure of membranes and their interactions with biomacromolecules (e.g. enzymes, peptides, proteins, nucleic acids). (
  • Using fluorescence and calorimetry methods, the researchers studied interactions between charged nanoparticles and membranes formed from single-component lipids. (
  • We investigate the interdependence of lipid-protein interactions through an interdisciplinary approach combining cell biology and synthetic biology as well as protein biochemistry, structural biology and biophysics. (
  • The structure also reveals interactions that are unique to the membrane-embedded complex, including helix 8 burial in the inner leaflet, ordered lysine and arginine side chains in the membrane interfacial regions, and lipid anchoring of the G protein in the membrane. (
  • Among them, dystrophin strengthens the sarcolemma through protein-lipid interactions, and its absence due to gene mutations leads to the severe Duchenne muscular dystrophy. (
  • SANS data for the protein/lipid complexes were obtained with contrast-matched bicelles under various phospholipid compositions to probe the role of electrostatic interactions. (
  • However, an asymmetric lipid distribution between the leaflets can be induced by fine tuning specific intermolecular interactions between the lipids. (
  • While interactions between lipids and amyloid-protein are generally discussed within the perspective of different protein species adsorbing to and perturbing the lipid membrane, the current work reveals amyloid formation in the presence of lipids as a co-aggregation process. (
  • One important consequence is that protein interactions will be mediated by the energy cost of deforming the membrane from its protein free state. (
  • This approach treats the energetics of membrane-protein interactions as a function of the material properties of the membrane such as bending rigidity and compressibility. (
  • Together, these considerations suggest the membrane lipid environment and in particular phosphoinositides and protein palmitoylation are likely to work in concert with ankyrin- and spectrin-based protein interactions in establishing and/or regulating membrane domains. (
  • Recent advances in structural research of membrane proteins provide new information about specific protein-lipid interactions. (
  • Tightly bound lipids in membrane protein structures are described and general principles of the binding interactions are deduced. (
  • Lipid binding is stabilized by multiple non-covalent interactions from protein residues to lipid head groups and hydrophobic tails. (
  • The stabilizing interactions differ between the electropositive and electronegative membrane sides. (
  • 6. The fatty acid composition of membrane lipids was altered markedly by a single feeding of safflower oil. (
  • This virtual session covers the biochemistry of lipid production in a variety of contexts. (
  • The content of the 4th edition reflects the enormous advances that have occurred since that time in the field of lipid biochemistry. (
  • This publication is unique in that it represents a bridge between the superficial coverage of the lipid field found in basic biochemistry text books and the highly specialized material contained in scientific review articles and monographs. (
  • 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. (
  • I would recommend this book both for students who have already taken an introductory course in biochemistry and for scientists researching lipids, lipoproteins and biomembranes. (
  • 1 LiMES - Life and Medical Sciences Institute, Membrane Biology and Lipid Biochemistry Unit, c/o Kekulé-Institut für Organische Chemie und Biochemie, University of Bonn, Bonn, Germany. (
  • Additionally, a working model of MgdA for the biosynthesis and flow of sugar lipids between Synechocystis membranes was proposed. (
  • Here, we identify a protein required for the biosynthesis of a unique archaeal lipid head group, calditol, whose production was considered to be restricted to a subset of archaeal thermoacidophiles. (
  • Lipid Intermediates in Bacterial Peptidoglycan Biosynthesis. (
  • This type of lipid bilayer, formed by the self-assembly of lipid molecules, is the basic structure of the cell membrane . (
  • Phospholipid molecules, like molecules of many lipids, are composed of a hydrophilic "head" and one or more hydrophobic "tails. (
  • In a water medium, the molecules form a lipid bilayer, or two-layered sheet, in which the heads are turned toward the watery medium and the tails are sheltered inside, away from the water. (
  • There is a pressing need to better understand the complex lipid bilayer that makes up this membrane, which limits the molecules that can leave or enter the cell. (
  • Research into the plasma membrane structure and behavior can provide invaluable information about whether, and to what extent, small molecules such as sugars, hormones and drugs, can permeate. (
  • Many different classes of lipids also are known to serve as metabolic precursors to various second messengers or as signaling molecules in their own right. (
  • The arrangements of lipids and various proteins, acting as receptors and channel pores in the membrane, control the entry and exit of other molecules and ions as part of the cell's metabolism. (
  • The diverse functionality of the biomembrane is achieved by a seemingly simple structure, two layers that are primarily made from lipid molecules and also some integral proteins, cholesterols, and other functional molecules [ 6 , 7 ]. (
  • that is, its constituent molecules are able to move relatively easy within the membrane, which resists bending and stretching but not shear [ 9 ]. (
  • Membrane-embedded proteins control the flux of molecules, energy, and information such that the segregated compartments function as a unified living cell. (
  • Pathway for membrane building blocks ( The lipid molecules of membranes als. (
  • The molecules form a bilayer in the membrane, with all of the heads pointing outwards and the fatty acid chains hanging in a zip-like interlay position. (
  • The molecules can anchor themselves in one of the two membrane layers with their lipophilic tail," explains Prof. Dieter Langosch of the TUM Chair of Biopolymer Chemistry. (
  • Prof. Langosch explains: "When the peptides bind the molecules, the surrounding membrane is briefly destabilized. (
  • Phase changes occurred in patches of membranes where phospholipid molecules swiveled after binding to charged nanoparticles. (
  • Furthermore, the membrane microdomains induced by BAR domains are expected to function as diffusion barriers, which may for example trap membrane-associated receptor and cargo molecules at the endocytic bud. (
  • G-protein coupled receptors (GPCRs) are the largest class of molecules involved in signal transduction across membranes, and represent major targets in the development of novel drug candidates in all clinical areas. (
  • Lipid composition is expected to play an important role in modulating membrane enzyme activity, in particular if the substrates are themselves lipid molecules. (
  • 4. Lipid metabolism in plants (K.M. Schmid, J.B. Ohlrogge). (
  • 10. Adipose tissue and lipid metabolism (D.A. Bernlohr, A.E. Jenkins, A.A. Bennaars). (
  • 2. Lipid metabolism in prokaryotes (C.O. Rock, S. Jackowski, J.E. Cronan, Jr.). 3. (
  • 10. Adipose tissue and lipid metabolism (D.A. Bernlohr, M.A. Simpson). (
  • At the ASBMB 2011 annual meeting, the "Lipid and Membrane Metabolism" theme will cover phosphoinositides, sphingolipids, phospholipases D and neutral lipids. (
  • Phosphoinositide metabolism is subject to exquisite spatial and temporal regulation both at the level of synthesis (by lipid kinases) and degradation (by phospholipases and phosphatases). (
  • And, Vytas A. Bankaitis (University of North Carolina School of Medicine) will round out the session by discussing the mechanisms by which PtdIns-transfer proteins act as coincidence detectors for the coupling of disparate pathways from lipid metabolism to production of functionally privileged phosphoinositide signaling pools. (
  • Crawford (2010) in his chapter Long-chain polyunsaturated fatty acids in human brain evolution reported, with regard to the language of lipids, that the importance of the increased complexity of these lipids was brought about by aerobic metabolism, whereby the simple language of prokaryotes, with only a few words, was developed into a vocabulary of over 1,000 words of eukaryote cells. (
  • Toxic effects of cadmium (7440439) (Cd), mercury (7439976) (Hg), zinc (7440666) (Zn), and selenium (7782492) (Se) on lipid peroxidative metabolism were investigated in rabbit alveolar macrophage cultures. (
  • Lipid Metabolism in Microalgae. (
  • Modeling Lipid Metabolism in Yeast. (
  • Players in the Nonpolar Lipid Game - Proteins Involved in Nonpolar Lipid Metabolism in Yeast. (
  • The roles of specific lipid binding and the probable mechanism leading to intracellular vesicle formation were also investigated. (
  • Thus, lipid distribution between various intracellular organelles must be properly regulated to insure appropriate membrane function. (
  • Specific recruitment of different proteins to distinct intracellular membranes is fundamental in the biology of eukaryotic cells, but the molecular basis for specificity is incompletely understood. (
  • While the question of the links between lipids and intracellular trafficking is of very broad relevance to any eukaryotic cells, this Research Topic focuses on their roles in plants. (
  • And what are the contributions of intracellular trafficking and lipid exchange at MCSs between organelles in the establishment of these patterns? (
  • FAAH (fatty acid amide hydrolase) is a membrane-bound enzyme that is responsible for the intracellular hydrolysis of the bioactive lipid AEA (anandamide or N -arachidonoylethanolamine) and other congeners known as eCBs (endocannabinoids) [ 1 ]. (
  • Hydrophobic matching, in which transmembrane proteins cause the surrounding lipid bilayer to adjust its thickness to match the hydrophobic surface of the protein, is a commonly accepted idea in biophysics, but one that until now has not been experimentally tested. (
  • Department of Molecular Membrane Biology, Max-Planck-Institute of Biophysics, Max-von-Laue-Str. (
  • Almost all intrinsic proteins contain special amino acid sequences, generally about 20- to 24-amino acids long, that extend through the internal regions of the cell membrane. (
  • 17. Lipid assembly into cell membranes (D.R. Voelker). (
  • So this is all still non-polar and the purple part principally because of this kind of being negative charge and just this the polar nature of this phosphodiester but that allows it to play a pretty cool role in cell membranes. (
  • The results indicated a doubling of lipid synthesis in the cell, which was triggered by the selective binding of MGS to anionic lipids. (
  • We show that deletion of this protein in Sulfolobus acidocaldarius prevents production of calditol-linked membrane lipids and, in turn, inhibits cell growth at extremely low pH. (
  • By forming a double layer with the polar ends pointing outwards and the nonpolar ends pointing inwards membrane lipids can form a 'lipid bilayer' which keeps the watery interior of the cell separate from the watery exterior. (
  • The bilayer formed by membrane lipids serves as a containment unit of a living cell. (
  • Functional roles of lipids are in fact many: They serve as regulatory agents in cell growth and adhesion. (
  • Both these cells synthesized iodolipids, as novel words of the chemical lipid language developed among cell membranes during the evolution of life. (
  • Once the NAG-NAM complex complex crosses the bacteria cell membrane into the periplasmic space, the terminal D-ala is cleaved off and the penultimate D-ala is cross linked to a DAP (forming a direct crosslink), or to a L-Lys (via a peptide interbridge) of another NAG-NAM complex. (
  • and bacitracin, a drug that prevents bactoprenol from being recycled (bactoprenol is a carrier lipid, a homolog of dolichol, that moves the NAM-NAG complex across the cell membrane). (
  • the outermost membrane is lost during exocytosis, the middle one is lost just prior to cell entry, and the remaining membrane fuses with the cell to allow the virus core to enter the cytoplasm and initiate a new infection. (
  • Lipid is an important constituent of cell membrane. (
  • A significant body of research worked on the relationship between membrane lipid and fatty acid composition and ability of cell to tolerate adverse change in temperature. (
  • Lipid analyses have been done with whole cell membrane isolated by different methods. (
  • Its plasma membrane is also different from most other cell membranes in lipid composition. (
  • The constitutive degradation of membrane components takes place in the acidic compartments of a cell, the endosomes and lysosomes. (
  • For instance, molecular signaling and transport in cells are governed by the association and insertion of proteins with the cell lipid membrane. (
  • Is the Subject Area "Cell membranes" applicable to this article? (
  • That is why the exact way how certain nanoparticle interact with human tissues and barriers, including cell membranes is still not well understood. (
  • They observed that these nanoparticles stay trapped in the cell membrane, as commonly accepted by the scientific community. (
  • But a surprise appears when they studied the case of superhydrophobic nanoparticles, as these nanoparticles could not only insert into the cell membrane but they could also escape this membrane spontaneously. (
  • Dr. Fleury and his team, designed a microfluidic experiment to form phospholipid bilayer systems, which can be considered as artificial cell membranes. (
  • Using the new imaging platform established at SUStech, researchers observed the multi-organelle interactive activities of cell division, lipid dynamics during plasma membrane separation, tunneling nanotubules formation, and mitochondrial cristae dissociation. (
  • Since cardiolipins are present in cell membranes of organisms from all domains of life, they are desired components of the synthetic cell. (
  • The lipids that form the cell membrane of archaea are structurally different from those in the other two domains of life,' Exterkate explains. (
  • What Is a Major Type of Lipid Found in Cell Membranes? (
  • This three-dimensional spherical bilayer becomes the cell membrane. (
  • Thin parts of the cell membranes of neurons turn out to be particularly vulnerable to a protein that collects in the brain of people with Alzheimer's disease, according to a University of Michigan researcher. (
  • Specifically, they were seeing that when they modified the composition of lipids in a cell membrane, the activity of an enzyme named FAAH increased. (
  • Metal Induced Lipid Peroxidation in Cell Membranes: Final Report on Project VKC-R22-147. (
  • A fascinating topic in cell biology, is how these subcellular patterns of lipids arise in the cell despite the constant exchange of membranes between the different cell compartments. (
  • In addition, understanding the organization and function of membrane contact sites (MCSs) is an actual challenge to unravel the complexity of lipid exchange during cell compartments interaction. (
  • How are lipid patterns in the cell achieved, both at the "macro" scale (i.e. between different membrane compartments or pole of the cell) and "nano" scale (segregation of lipids in domains within a single membrane)? (
  • How membrane physicochemical properties participate in membrane trafficking and cell signaling? (
  • Lipids are the building blocks of cell membranes. (
  • Nanodiscs are currently used to incorporate membrane protein during cell-free expression. (
  • Cell-contact-dependent Outer Membrane Exchange in Myxobacteria. (
  • Contributions of Membrane Lipids to Bacterial Cell Homeostasis Upon Osmotic Challenge. (
  • Role of Lipid Domains in Bacterial Cell Processes. (
  • Ion channels are a sort of transmembrane protein-that's to say, they span the whole cell membrane -which, in conjunction with proteins, allow specific ions to pass from one side of the membrane to the other. (
  • BAR proteins can create stable lipid microdomains at cell membranes. (
  • formation of the prospore membrane inside the cell. (
  • Cell-free expression systems in combination with nanodiscs (discoidal lipid bilayer particles) offer a valuable approach to probe membrane proteins in situ. (
  • Currently we focus on membrane protein folding in situ using cell-free expression systems and nanodiscs to monitor synthesis and folding events of bacteriorhodopsin during the protein translation by the ribosome. (
  • Ankyrin-G and βII-spectrin colocalize at sites of cell-cell contact in columnar epithelial cells and promote lateral membrane assembly. (
  • This study identifies two critical inputs from lipids that together provide a rationale for how ankyrin-G and βII-spectrin selectively localize to Madin-Darby canine kidney (MDCK) cell lateral membranes. (
  • After isolation of caveolae and using electron microscopy on cell membranes, the insulin receptor was demonstrated to be localised in caveolae of human adipocytes. (
  • The results support previous STED nanoscopy measurements and suggest that, at least for nontreated cells, the transient interaction of a single lipid is confined to macromolecular dimensions. (
  • The envelope stress sensor, CpxA and its interaction with E. coli membranes were studied. (
  • Multi-resonant mid-IR nanoantennas are leveraged to enhance the vibrational absorption signals associated with biomimetic lipid membrane formation, polypeptide/membrane interaction, and vesicular cargo release on the sensor surface. (
  • The new sensor achieves this by accessing the distinct chemical fingerprint information of proteins, lipids, peptides, or other biochemical and allows simultaneous and independent monitoring of their interaction dynamics. (
  • In particular, the study shows that the sensor can spectroscopically resolve the interaction of biomimetic lipid membranes with different peptides as well as the dynamics of vesicular cargo release. (
  • Based on these concerns, the team of theoretical physics at Universitat Rovira i Virgili in Tarragona, led by Dr. Vladimir Baulin, the coordinator of European Network ITN SNAL , designed a research project to investigate the interaction between nanoparticles and lipid membranes. (
  • With this experimental setup, they explored the interaction of individual nanoparticles with such an artificial membrane. (
  • The interaction leads to the formation of lipid-protein co-aggregates with distinct structure, dynamics and morphology compared to assemblies formed by either lipid or protein alone. (
  • We believe that development in deciphering molecular details of the nature of GPCR-lipid interaction would lead to better insight into our overall understanding of GPCR function in health and disease. (
  • One method to gain a profound understanding of the dynamics in lipid membranes and their interaction with other system components is by modeling these systems by computer simulations. (
  • DHHC5/8 and βII-spectrin colocalize with ankyrin-G in micrometer-scale subdomains within the lateral membrane that are likely sites for palmitoylation of ankyrin-G. Loss of either DHHC5/8 or ankyrin-G-βII-spectrin interaction or βII-spectrin-phosphoinositide recognition through its pleckstrin homology domain all result in failure to build the lateral membrane. (
  • 1. Functional roles of lipids in membranes (W. Dowhan, M. Bogdanov). (
  • Physical properties and functional roles of lipids in membranes (P.R. Cullis, D.B. Fenske, M.J. Hope). (
  • 9. Ether-linked lipids and their bioactive species (F. Snyder, Ten-ching Lee, R.L. Wykle). (
  • SQDG, an anionic lipid was found to be the species of the membrane that increased the MgdA activity 7-fold whereas two other lipids (PG and PE) had only minor effects on MgdA. (
  • At this onset a comprehensive review is needed to cover changes of sperm membrane lipid composition of different species under different cryopreservation conditions. (
  • Phospholipid molecular species and headgroup compositions were determined for sarcoplasmic reticular and microsomal membranes in two species of Sonoran desert cyprinid fish ( Agosia chrysogaster Girard and Notropis lutrensis Girard) trapped in an isolated pool of a desert stream. (
  • The lipid A species were isolated and identified by matrix assisted laser ionization desorption-time of flight/tandem mass spectrometry. (
  • Thus, distribution and mobility of specific lipid species at the plasma membrane appears to precisely regulated by membrane-associated proteins. (
  • However, it remains to be determined whether certain species of lipids are required for spore formation in yeast. (
  • are at particularly high risk of LPO relative to less unsaturated lipid species and lipids with a choline headgroup. (
  • Many membrane proteins selectively bind defined lipid species. (
  • The soybean model also showed that lipids with similar amounts of unsaturation tended to cluster together, behavior scientists had not previously observed for these plant lipids. (
  • Large membrane pores able to transport macromolecular contents represent an interesting model to test theoretical predictions that assign active-like (non-equilibrium) behavior to the permeability contributions to the enhanced membrane fluctuations existing in permeable membranes [Maneville et al. (
  • This binding-induced behavior, where the same lipid can coexist in two different phases, offers a new mechanism for modulating stiffness in membranes. (
  • By collapsing the complexity of planar 2D membranes down to one dimension, fundamental investigations of bimolecular behavior become possible in one dimension. (
  • Light induced peroxidation of an unsaturated phospholipid membrane leads to membrane surface area increase, revealed by micropipette aspiration. (
  • Computer illustration showing the phospholipid membrane (diagonal) that surrounds cells (lower right). (
  • Now, Granick, Zhang, graduate research assistant Bo Wang and research scientist Sung Chul Bae show that a phospholipid membrane can coexist in two phases - solid and liquid - according to what binds to it. (
  • Here we used cryo-electron microscopy to elucidate the structure of an agonist-bound activated DRD2-G i complex reconstituted into a phospholipid membrane. (
  • Studies by Pekka Lappalainen laboratory at Institute of Biotechnology, University of Helsinki, Finland, now reveal that BAR domain proteins not only bend membranes, but also generate extremely stable lipid microdomains by inhibiting the lateral diffusion of certain lipids nearly completely. (
  • Beyond the simple cataloguing of signaling events compartmentalized by these membrane microdomains, recent studies have revealed the surprisingly central importance of dynamic remodeling of membrane lipid domains to immune signaling. (
  • Membrane-mediated precipitation of calcium phosphate in model liposomes with matrix vesicle-like lipid composition. (
  • Likewise, the suspending medium remained stable for up to 72 h when precipitation was induced within the aqueous interiors of the liposomes by encapsulating pH 7.4-buffered 50 mM PO4 solutions in the interior spaces and making the enclosing membranes permeable to external solution Ca2+ ions with the ionophore X-537A. (
  • However, extraliposomal precipitation readily occurred under these latter conditions when phosphatidylserine (PS) and sphingomyelin (Sph) were deleted from the MV-like lipid formulation used to prepare the liposomes. (
  • We examined in vivo membrane lipid peroxidation in erythrocytes of diabetic subjects and its possible relationship with hyperglycemia. (
  • There was a significantly increased membrane lipid peroxidation in diabetic erythrocytes compared with nondiabetic erythrocytes. (
  • This suggests that peroxidation of membrane lipids and accumulation of MDA occurs in erythrocytes of diabetic patients. (
  • Preincubation of macrophages with Zn(2+) protected the cells against the disruptive action of Cd(2+), but the protective action could not be explained by any observed increase or decrease in lipid peroxidation. (
  • Cold acclimation of ectotherms results typically in enhanced oxidative capacities and lipid remodeling, changes that should increase the risk of lipid peroxidation (LPO). (
  • Locally induced lipid phase transitions reveal how protein-free lipid membranes exhibit transient and localized permeation. (
  • Shivastava's work we should mention, would actually predict that liberation of heat near phase transitions can actually lead to condensation in lipids. (
  • Psychrophilic bacteria--molecular adaptations of membrane lipids. (
  • Researchers at the University of Maryland, in College Park, have developed a detailed computational model of the soybean plasma membrane that provides new structural insight at the molecular level. (
  • We have reconstituted the core machinery for regulating lipid saturation in baker's yeast to study its molecular mechanism. (
  • By combining molecular dynamics simulations with experiments, we uncover a remarkable sensitivity of the transcriptional regulator Mga2 to the abundance, position, and configuration of double bonds in lipid acyl chains, and provide insights into the molecular rules of membrane adaptation. (
  • Rather, we show that Mga2 senses the molecular lipid-packing density in a defined region of the membrane. (
  • Also, the three-dimensional molecular shape of some lipids and proteins results in a nonzero spontaneous curvature that affects the geometry of the biomembrane in their neighborhood. (
  • These important proof of concept experiments pave the way for applying these biosensors to investigate the molecular mechanisms underpinning important processes that have been linked to human diseases, such pore formation and membrane disruption induced by protein aggregation in neurodegenerative diseases such as Alzheimer's and Parkinson's disease. (
  • The changes in membrane structure profoundly affect the molecular environment and thus the local diffusion properties. (
  • Here, we report an integrated experimental and molecular dynamics simulation study to investigate the self-assembly of amphiphilic Janus particles on a lipid membrane. (
  • In turn, lipid patterning is an integral part of membrane trafficking events, since distinct lipids recruit a multitude of trafficking regulators (e.g. coat proteins, molecular motors, etc.) and directly influence membrane physicochemical properties (e.g. packing defect, electrostatics, curvature), which regulate compartment morphodynamics. (
  • Currently, the membrane lipid analyses provide additional information not easily provided by other molecular techniques. (
  • Molecular, dynamic, and structural origin of inhomogeneous magnetization transfer in lipid membranes. (
  • We utilize molecular dynamics simulations to demonstrate that gold nanoparticles functionalized with a mixed-monolayer of hydrophobic and hydrophilic alkanethiol ligands can act as synthetic analogues of these fusion proteins and mediate lipid membrane fusion by catalyzing the formation of a toroidal stalk between adjacent membranes and enabling the formation of a fusion pore upon influx of Ca$^{2+}$ into the exterior solvent. (
  • To fully understand the impact of these processes on the molecular level, it is necessary to develop tools that can access the molecular properties of free-floating model membranes label-free. (
  • Here we investigate the effect of the oxidized phospholipid 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC) on a model membrane of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) using a combination of 13 C- 1 H dipolar-recoupling nuclear magnetic resonance (NMR) experiments and united-atom molecular dynamics (MD) simulations. (
  • So the change in membrane lipid composition due to cold shock or cryopreservation may be looked upon as response of spermatozoa to a certain stressed condition. (
  • Lipids as Receptors. (
  • Md. Jafurulla and A. Chattopadhyay, "Membrane Lipids in the Function of Serotonin and Adrenergic Receptors", Current Medicinal Chemistry (2013) 20: 47. (
  • This Faraday Discussion considered recent developments in the study of biomembrane structure, ordering and dynamics, with particular emphasis on the roles of lipids in these phenomena. (
  • Our findings suggest that membrane property sensors have evolved remarkable sensitivities to highly specific aspects of membrane structure and dynamics, thus paving the way toward the development of genetically encoded reporters for such properties in the future. (
  • Now an advanced technique called SPOT (Spectrum and Polarization Optical Tomography) is giving researchers a 'street view' of the vital lipid membranes surrounding organelles and by so doing opens up the opporutnies to study the sophisticated world of lipid dynamics. (
  • Combined with lipophilic probes, the team successfully revealed more than ten types of organelles simultaneously, and their sophisticated lipid dynamics. (
  • 2020) High-dimensional super-resolution imaging reveals heterogeneity and dynamics of subcellular lipid membranes. (
  • Nanowerk News ) Eukaryotic cells are compartmentalized by membranes, whose shape and dynamics are precisely regulated to maintain their correct functions. (
  • Hongxia Zhao is now continuing studies on regulation of lipid dynamics as an Academy Research Fellow at University of Helsinki. (
  • We show that hydrophobic mismatch between lipids with different acyl chain lengths tunes the dynamics in a way not achievable in single component systems. (
  • The aim of this thesis is to study dynamics of chloroplast water, thylakoid membrane lipids and proteins in different environmental conditions. (
  • An overview of various methods to measure thylakoid membrane dynamics and advantages & limitations of these methods taken from that chapter is listed below. (
  • In contrast, sterols have a complex hydrocarbon ring structure as the lipid-soluble region and a hydroxyl grouping as the water-soluble region. (
  • the same picture is still considered valid, and uncertainties in membrane structure have been related in past years to the structural relations existing between proteins and the lipid bilayer. (
  • The results of their large-scale simulations highlight unique properties of the soybean plasma membrane and demonstrate a microscale membrane structure in which similar lipids tend to cluster together. (
  • The last model system was another integral membrane protein with a distinct structure but also a different function. (
  • Studies of membrane proteins have revealed a direct link between the lipid environment and the structure and function of some of these proteins. (
  • It is typical for the responding lipid membrane that small changes in the membrane environment can lead to major changes in membrane structure. (
  • Recent results suggest that, in the thylakoid membrane, membrane proteins force all the lipids to adopt a bilayer structure, and that the non-bilayer-forming lipids in the thylakoid membrane serve to drive the formation of membrane stacks. (
  • Dynamic Membrane Structure: Function Analysis by Means of Chemical Probes. (
  • Membrane Structure:Function Analysis Through Reconstitution In Vitro. (
  • Most of the dystrophin protein consists of a central domain made of 24 spectrin-like coiled-coil repeats (R). Using small angle neutron scattering (SANS) and the contrast variation technique, we specifically probed the structure of the three first consecutive repeats 1-3 (R1-3), a part of dystrophin known to physiologically interact with membrane lipids. (
  • Finally, our strategy opens up new possibilities for structure determination of peripheral and integral membrane proteins not compatible with different high-resolution structural methods. (
  • Acetylcholine receptor and acetylcholinesterase were incorpoated into these membranes, Producing a change in lipid phase structure. (
  • This is shown with dipalmitoylphosphoserine and dioleoylphosphocholine mixtures creating a membrane structure that allows intermolecular H-bonding between the phosphate and amine groups of the lipids. (
  • This indicates a tightly packed layer of ions around the membrane that needs to be considered when modelling the interfacial structure around membranes. (
  • The results would be useful for redesigning the bacterial membrane structure and for developing lipid A vaccine adjuvant. (
  • In the present study, using a combined experimental and computational approach, we show that membrane lipids modulate the structure, subcellular localization and activity of FAAH. (
  • This study demonstrates the utility of the REDOR NMR technique for the elucidation of the oligomeric structure of membrane proteins. (
  • The Lipid II's glycan chains are polymerized and the its stem peptides are cross linked. (
  • Once Lipid II is on the periplasmic side of the membrane, it undergoes the polymerization of the glycan chains and the cross-linking of the stem peptides. (
  • On the experimental side, the studies of diffuse scattering are currently extended to cover also charged lipids and lipid/peptides mixtures. (
  • Our peptides stretch through the membrane like a corkscrew. (
  • Learn, for example, about gut bacteria as they scavenge fatty acids to build new membranes and chloroplasts as they sense and adapt to cold. (
  • Membrane lipid homeostasis in bacteria. (
  • Here, the principal genetic and biochemical processes that are responsible for membrane lipid homeostasis in bacteria are reviewed. (
  • Our findings also suggest that archaea more broadly, like bacteria, employ radical S -adenosylmethionine proteins to modify membrane lipids in ways that confer protective effects when environmental conditions, such as pH, fluctuate significantly. (
  • Deforming the membrane in this way would ultimately enable the bacteria to infect healthy neighbouring cells. (
  • Concise chapters, written by experts in the field, cover a wide spectrum of topics on lipid and membrane formation in microbes (Archaea, Bacteria, eukaryotic microbes). (
  • Functional Roles of Individual Membrane Lipids in Bacteria, Archaea and Eukaryotic Microbes. (
  • Outer Membrane Extension Nanowires of Bacteria. (
  • Regulation of Membrane Lipid Homeostasis in Bacteria upon Temperature Change. (
  • Lipid A, the hydrophobic anchor of lipopolysaccharide (LPS), is an essential component in the outer membrane of Gram-negative bacteria. (
  • Cells produce an array of lipids using tightly controlled enzymes to ensure proper physical properties of membranes. (
  • Other talks cover homeostatic control of lipid-synthesis enzymes and metabolic engineering through systems biology. (
  • Together with endosomal and lysosomal lipid-binding proteins, the Niemann-Pick disease, type C2-protein, the GM2-activator, and the saposins sap-A, -B, -C, and -D, a suitable membrane lipid composition is required for degradation of complex lipids by hydrolytic enzymes. (
  • It can produce lipids that, in bacterial cells, for example, require many different enzymes. (
  • Formation of Bacterial Glycerol-based Membrane Lipids: Pathways, Enzymes, Reactions. (
  • The non-equilibrium character of the membrane fluctuations in a permeation field, even if the membrane pores are mere passive transporters, is clearly demonstrated. (
  • It has already been shown from studies of the fluctuations that can be detected in very small membrane currents, that alamethicin forms transient pores of some 0.6 nm in diameter and that, for small inorganic ions, these are poorly selective. (
  • This is a complex molecule that is thought to be translocated to the outer side of the cytoplamsimic membrane by integral membrane proteins of the shape, elongation, division, and sporulation family. (
  • The first two rows of the lipid bilayer are made of polygonal lipids with the generic hydrophilic head and hydrophobic tails. (
  • Julie D. Saba (Children's Hospital Oakland Research Institute) will discuss her recent work on the role of sphingosine-1-phosphate lyase in DNA repair as an example of the underinvestigated problem of lipid signaling in the nucleus. (
  • report a mechanism through which TMEM24, a lipid transport protein that concentrates at endoplasmic reticulum-plasma membrane contact sites, regulates the pulsatility of cytosolic Ca 2+ and phosphoinositide signaling. (
  • Functional Roles of Non-membrane Lipids in Bacterial Signaling. (
  • Membranes, composed of a variety of lipids and other biomolecules, mediate signaling processes between cells and their aqueous environment. (
  • 2 , 4 , 5 ), the objective is to synthesize and interpret emerging insights on how genetic and environmental modification of raft lipid plays a fundamental role in determining immune signaling and disease. (
  • Distinct chemical families of lipids endow divergent biophysical properties to the membranes in which they reside. (
  • In the future, similar experiments may be applied to more complex lipid-membrane systems, including lipid/peptide, lipid/protein or lipid/DNA assemblies. (
  • Finally, I present research to which I contributed on the thickness mismatch of coexisting liquid phases in model lipid membranes. (
  • These tails are repelled by water and dissolve readily in organic solvents, giving the molecule its lipid character. (
  • And those non-polar tails become attracted to another set of non-polar tails, and another polar head right here, and this forms a two layer membrane to our cells. (
  • In computer simulations, the researchers first created what they call a "perfect bilayer", in which all of the lipid tails stay in place within the membrane. (
  • Cardiolipins - so-called because they were first identified in heart cells - are slightly different since they are made up of a single head group that is attached to four lipid tails. (
  • The membrane metabolites of polyunsaturated fatty acids (PUFAs) have an essential role in intercellular biochemical communications. (
  • It is thought that the distinct ether lipid membranes of archaea allow them to thrive in environmental extremes. (
  • Distinct lipid-binding motifs have been identified for lipids with defined head groups in membrane protein structures. (
  • Experimental studies and coarse grained simulations demonstrate an amphiphilic polymer when penetrating deeper into the membrane due to increasing hydrophobicity can suppress permeability. (
  • From this data as well as complementary neutron scattering data, the membrane fluctuation spectrum g(r) can be determined, and thereby also elasticity parameters such as bilayer bending rigidity K and compressional modulus B as a function of T. (
  • However, current label-free techniques struggle to differentiate protein insertion, chemical release and membrane disruption processes, thus forcing experimentalists to rely on multiple techniques that usually require different experimental settings. (
  • Diffusional transport across lipid membranes can be highly complex and include several parallel transport processes. (
  • Readers will discover significant chapters on microbial lipid-carrying biomolecules and lipid/membrane-associated structures and processes. (
  • Saturated lipid acyl chains tend to form non-fluid, tightly packed gel phases at physiological temperatures, whereas unsaturated lipid acyl chains fluidize the bilayer. (
  • This two-way coupling between shape and composition means that deformations exhibited by biomembranes are strongly influenced by their heterogeneous composition, while the spatial ordering of composition is modulated by the geometry of the membrane [ 16 , 18 - 23 ]. (
  • Changes of macroscopic properties and morphology of POPC/MePha model membranes upon irradiation by visible light are recorded by means of contact angle measurements and atomic force microscopy, demonstrating clearly the possibility to use these methods for the study of photodestruction of artificial lipid membranes on solid substrates, but also for a comparative study of the efficiency of novel photosensitizers. (
  • This article is concerned primarily with the mechanism of the potential-dependent conductance induced in artificial lipid membranes by the cyclic polypeptide antibiotic alamethicin. (
  • Historically lipids were thought to merely serve a structural role. (
  • The results show that specific structural lipids remain bound in the gas phase and can be counted. (
  • It had been expected that structural changes in the membrane would be the culprit, but that was not the case. (
  • The collected structural information has identified the catalytic mechanism of FAAH, but a role for the surrounding membrane lipids in controlling the enzyme's activity remains as yet unknown. (
  • Caveolae are invaginations of the plasma membrane, characterised by the structural protein caveolin. (
  • Cells, and the organelles within them, are surrounded by lipid-bilayer membranes that compartmentalize biochemical reactions and pathways. (
  • Furthermore, preferential anionic lipid sequestering by MGS was shown to induce a different fatty acid modeling of E. coli membranes. (
  • However, 30% of the neutral lipid fraction was accounted for by glycerides and fatty acid. (
  • This patchiness in phospholipid membranes is fundamental to their use as biomolecules and biosensors. (
  • Alternative more rigorous theories (renormalisation group theories, self-consistent theories) and computer simulations on reasonably large stacks of membranes and lateral system size may help to gain more understanding. (
  • We identify aspartate-histidine-histidine-cysteine 5/8 (DHHC5/8) as ankyrin-G palmitoyltransferases required for ankyrin-G lateral membrane localization and for assembly of lateral membranes. (
  • We also find that βII-spectrin functions as a coincidence detector that requires recognition of both ankyrin-G and phosphoinositide lipids for its lateral membrane localization. (
  • The formation, association, and assembly of soluble precursors onto a lipid carrier occurs in the cystoplasm. (
  • Phase segregation of membranal components, such as proteins, lipids, and cholesterols, leads to the formation of aggregates or domains that are rich in specific constituents. (
  • When these particles collide randomly with the membrane, they generate local forces that lead to the formation of tethers, antennae and other structures. (
  • The most conducive conditions were when particles filled about 3 % of the vesicle, leading to the formation of the craziest membrane structures. (
  • A team of physicists led by the researcher of the URV's Department of Chemical Engineering Vladimir Baulin has designed an experiment that simulates the formation of a new type of lipid raft on a nanometric scale around objects encrusted in the membranes such as proteins and ion channels . (
  • In this study, we analyzed the requirement of the synthesis of phosphatidylethanolamine (PE), phosphatidylcholine (PC), and ergosterol for spore formation using strains in which the synthesis of these lipids can be controlled. (
  • As a first comprehensive and quantitative analysis of purified caveolae from primary cells, our results provide a firm basis for the examination of caveolae formation using artificial membranes. (
  • A cytosolic deacylase, APT2, is S-acylated by zDHHC3 and zDHHC7 and is predicted to deform the lipid bilayer to extract acyl chains, capturing them within a hydrophobic pocket. (
  • The lower the number of acyl chains in lipid A, the stronger the membrane permeability. (