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.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
The rate dynamics in chemical or physical systems.
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.
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.
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.
Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.
Established cell cultures that have the potential to propagate indefinitely.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
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.
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.
Lipid A is the biologically active component of lipopolysaccharides. It shows strong endotoxic activity and exhibits immunogenic properties.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Detergent-insoluble CELL MEMBRANE components. They are enriched in SPHINGOLIPIDS and CHOLESTEROL and clustered with glycosyl-phosphatidylinositol (GPI)-anchored proteins.
The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
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 characteristic three-dimensional shape of a molecule.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.
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.
Synthetic phospholipid used in liposomes and lipid bilayers to study biological membranes. It is also a major constituent of PULMONARY SURFACTANTS.
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.
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.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A synthetic phospholipid used in liposomes and lipid bilayers for the study of biological membranes.
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.
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.
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 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 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 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.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Proteins found in any species of bacterium.
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.
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.
Glycoproteins found on the membrane or surface of cells.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
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.
A class of sphingolipids found largely in the brain and other nervous tissue. They contain phosphocholine or phosphoethanolamine as their polar head group so therefore are the only sphingolipids classified as PHOSPHOLIPIDS.
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
Single membrane vesicles, generally made of PHOSPHOLIPIDS.
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.
A change of a substance from one form or state to another.
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).
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.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The thermodynamic interaction between a substance and WATER.
Elements of limited time intervals, contributing to particular results or situations.
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.
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 physical characteristics and processes of biological systems.
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.
Eighteen-carbon essential fatty acids that contain two double bonds.
Transport proteins that carry specific substances in the blood or across cell membranes.
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)
A bacterium which causes mastitis in cattle and occasionally in man.
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 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.
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.
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
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.
An organism originally isolated from sewage, manure, humus, and soil, but recently found as a parasite in mammals and birds.
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).
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.
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.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
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 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)
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
Characteristics or attributes of the outer boundaries of objects, including molecules.
The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.
FATTY ACIDS found in the plasma that are complexed with SERUM ALBUMIN for transport. These fatty acids are not in glycerol ester form.
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 sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
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.
Techniques used to separate mixtures of substances based on differences in the relative affinities of the substances for mobile and stationary phases. A mobile phase (fluid or gas) passes through a column containing a stationary phase of porous solid or liquid coated on a solid support. Usage is both analytical for small amounts and preparative for bulk amounts.
The study of significant causes and processes in the development of mental illness.
The sum of the weight of all the atoms in a 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.
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.
Cyclic GLUCANS consisting of seven (7) glucopyranose units linked by 1,4-glycosidic bonds.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
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 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.
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)
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 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.
Proteins prepared by recombinant DNA technology.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
The accumulation of an electric charge on a object
Preparation for electron microscopy of minute replicas of exposed surfaces of the cell which have been ruptured in the frozen state. The specimen is frozen, then cleaved under high vacuum at the same temperature. The exposed surface is shadowed with carbon and platinum and coated with carbon to obtain a carbon replica.
The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Proteins obtained from ESCHERICHIA COLI.
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
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.
Computer-based representation of physical systems and phenomena such as chemical processes.
Surface ligands, usually glycoproteins, that mediate cell-to-cell adhesion. Their functions include the assembly and interconnection of various vertebrate systems, as well as maintenance of tissue integration, wound healing, morphogenic movements, cellular migrations, and metastasis.
A group of tetraterpenes, with four terpene units joined head-to-tail. Biologically active members of this class are used clinically in the treatment of severe cystic ACNE; PSORIASIS; and other disorders of keratinization.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
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.
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)
Cellular uptake of extracellular materials within membrane-limited vacuoles or microvesicles. ENDOSOMES play a central role in endocytosis.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
A 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.
FATTY ACIDS in which the carbon chain contains one or more double or triple carbon-carbon bonds.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
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)
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 degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
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)
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
A genus of gram-negative, oxidase-positive, nonfermentative rods which are motile by means of a single flagellum. Afipia felis and BARTONELLA HENSELAE are causative agents of CAT-SCRATCH DISEASE. (From Bergey's Manual of Determinative Bacteriology, 9th ed)
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.
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.
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.
The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
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 computer simulation developed to study the motion of molecules over a period of time.
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 formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
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.
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)
Structures which are part of the CELL MEMBRANE or have cell membrane as a major part of their structure.
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).
Minute projections of cell membranes which greatly increase the surface area of the cell.
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.
Derivatives of PHOSPHATIDIC ACIDS that lack one of its fatty acyl chains due to its hydrolytic removal.
The measurement of the quantity of heat involved in various processes, such as chemical reactions, changes of state, and formations of solutions, or in the determination of the heat capacities of substances. The fundamental unit of measurement is the joule or the calorie (4.184 joules). (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
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)
The relationship between the dose of an administered drug and the response of the organism to the drug.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
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.
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.
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 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.
A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
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.
An amino alcohol with a long unsaturated hydrocarbon chain. Sphingosine and its derivative sphinganine are the major bases of the sphingolipids in mammals. (Dorland, 28th ed)
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.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
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.
Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.
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.
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.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.
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.
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)
Antibodies produced by a single clone of cells.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
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.
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.
The ability of a substrate to allow the passage of ELECTRONS.
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 group of peptide antibiotics from BACILLUS brevis. Gramicidin C or S is a cyclic, ten-amino acid polypeptide and gramicidins A, B, D are linear. Gramicidin is one of the two principal components of TYROTHRICIN.
Substances that reduce the growth or reproduction of BACTERIA.
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 network of filaments, tubules, and interconnecting filamentous bridges which give shape, structure, and organization to the cytoplasm.
The process of cleaving a chemical compound by the addition of a molecule of water.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
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.
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.
Adherence of cells to surfaces or to other cells.
Lipid-containing polysaccharides which are endotoxins and important group-specific antigens. They are often derived from the cell wall of gram-negative bacteria and induce immunoglobulin secretion. The lipopolysaccharide molecule consists of three parts: LIPID A, core polysaccharide, and O-specific chains (O ANTIGENS). When derived from Escherichia coli, lipopolysaccharides serve as polyclonal B-cell mitogens commonly used in laboratory immunology. (From Dorland, 28th ed)
Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.
Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.
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).)
Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.
A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.
Cellular release of material within membrane-limited vesicles by fusion of the vesicles with the CELL MEMBRANE.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
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)
Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.
A specific monosialoganglioside that accumulates abnormally within the nervous system due to a deficiency of GM1-b-galactosidase, resulting in GM1 gangliosidosis.
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.
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)
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
A naphthalene derivative with carcinogenic action.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes.[4][5] Lipids ... such as the cellular plasma membrane and the intracellular membranes of organelles; in animal cells, the plasma membrane ... Scientists sometimes broadly define lipids as hydrophobic or amphiphilic small molecules; the amphiphilic nature of some lipids ... They comprise a large number of secondary metabolites and natural products from animal, plant, bacterial, fungal and marine ...
... from the cell membrane or mutations that disrupt transport results in the accumulation of lipid A in the inner cell membrane ... Various types of membranes from different sources (e.g. insect cells, transfected or selected mammalian cell lines) are used in ... Since the lipid cannot be stable for a long time in the chamber environment, lipid A and other hydrophobic molecules may "flip ... Poolman B, Spitzer JJ, Wood JM (Nov 2004). "Bacterial osmosensing: roles of membrane structure and electrostatics in lipid- ...
The functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have ... Cell Biology Nomenclature IUPAC nomenclature of lipids IUPAC glossary entry for the lipid class of molecules Databases LIPID ... as the cellular plasma membrane and the intracellular membranes of organelles; in animal cells, the plasma membrane physically ... They comprise many secondary metabolites and natural products from animal, plant, bacterial, fungal and marine sources, and ...
Phosphatidylinositol, a membrane lipid required for cell-cell interaction, in the bacteria is also synthesised by the protozoan ... a major membrane lipid (atypical of bacterial membranes), and the highly reduced peptidoglycan layer, which shows reduced or ... As each symbiont is each of a single bacterium and a protozoan, and each daughter cell contains the same number, the two cells ... In return the protozoan offers its enzymes for the complete metabolic pathways for the biosysnthesis of amino acids, lipids and ...
Lpp connects the outer membrane to the peptidoglycan. Lpp is anchored to the outer membrane by its amino-terminal lipid group. ... Silhavy TJ, Kahne D, Walker S (2010). "The bacterial cell envelope". Cold Spring Harbor Perspectives in Biology. 2 (5): a000414 ... a cysteine with lipids attached). BLP tightly links the two layers and provides structural integrity to the outer membrane. The ... specifically to diaminopimelic acid molecules) and is embedded in the outer membrane by its hydrophobic head ( ...
... with an average lipid molecule diffusing ~2 µm, approximately the length of a large bacterial cell, in about 1 second. It has ... 1935 - Hugh Davson and James Danielli proposed that lipid membranes are layers composed by proteins and lipids with pore-like ... They used Sendai virus to force human and mouse cells to fuse and form a heterokaryon. Using antibody staining, they were able ... cell-cell signaling, apoptosis, cell division, membrane budding, and cell fusion. The fluid mosaic model is the most acceptable ...
Lipid anchored proteins. Covalently bound to single or multiple lipid molecules; hydrophobically insert into the cell membrane ... Bacterial cells provide numerous examples of the diverse ways in which prokaryotic cell membranes are adapted with structures ... Cell membranes contain a variety of biological molecules, notably lipids and proteins. Composition is not set, but constantly ... plasmatic membrane (Pfeffer, 1900),[13] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[14][15] Some ...
... immature egg cells) are not consistent with a lipid bilayer as they lack a bilayer and do not consist of lipids.[48] Rather, ... Lipid anchored proteins. Covalently bound to single or multiple lipid molecules; hydrophobically insert into the cell membrane ... Bacterial cells provide numerous examples of the diverse ways in which prokaryotic cell membranes are adapted with structures ... plasmatic membrane (Pfeffer, 1900),[15] plasma membrane, cytoplasmic membrane, cell envelope and cell membrane.[16][17] Some ...
... widely distributed in the mammalian cell membranes as a membrane stabilizing agents but absent in bacterial cell membranes; and ... the transmembrane potential of bacterial cells is more negative than that of normal mammalian cells, so bacterial membrane will ... Human defensins have been thought to act through a similar mechanism, targeting cell membrane lipids as part of their function ... Alternately, they may penetrate into the cell to bind intracellular molecules which are crucial to cell living. Intracellular ...
The bacterial cell is surrounded by a cell membrane, which is made primarily of phospholipids. This membrane encloses the ... but also a second outer layer of lipids. In many bacteria, an S-layer of rigidly arrayed protein molecules covers the outside ... Unlike cells of animals and other eukaryotes, bacterial cells do not contain a nucleus and rarely harbour membrane-bound ... bacteria have a relatively thin cell wall consisting of a few layers of peptidoglycan surrounded by a second lipid membrane ...
It is a component of the cell plasma membrane that modulates cell signal transduction events, and appears to concentrate in ... The name ganglioside was first applied by the German scientist Ernst Klenk in 1942 to lipids newly isolated from ganglion cells ... lipid rafts[citation needed]. Recently, gangliosides have been found to be highly important molecules in immunology. Natural ... These carbohydrate head groups also act as specific receptors for certain pituitary glycoprotein hormones and certain bacterial ...
Lipid bilayer - A membrane composed of two layers of lipid molecules (usually phospholipids). The lipid bilayer is a critical ... Bacterial conjugation - Transfer of genetic material between bacterial cells by direct cell-to-cell contact or by a bridge-like ... lipids, and cellular debris. lysosomes act as the waste disposal system of the cell by digesting unwanted materials in the ... especially animal cells. Cell disruption, and cell unroofing - methods for releasing molecules from cells Cell fractionation - ...
Fatty acid are essential components of lipid bilayers that form cell membranes as well as fat energy stores in animals. Natural ... The basic structure of cells and of organisms are also composed of primary metabolites. These include cell membranes (e.g. ... One molecule of acetyl-CoA (the "starter unit") and several molecules malonyl-CoA (the "extender units") are condensed by fatty ... Primary metabolites include carbohydrates, lipids, amino acids, and nucleic acids which are the basic building blocks of life. ...
Membrane proteins often serve as receptors or provide channels for polar or charged molecules to pass through the cell membrane ... "Green fluorescent protein as a reporter for macromolecular localization in bacterial cells". Methods (San Diego, Calif.). 20 (1 ... membrane lipids and proteins; cellular organelles, and nucleic acids. Precipitation by a method known as salting out can ... "Lipid-protein interactions in double-layered two-dimensional AQP0 crystals". Nature. 438 (7068): 633-38. Bibcode:2005Natur.438 ...
Cell membrane. Ether-linked lipids, pseudopeptidoglycan. Ester-linked lipids, peptidoglycan. Ester-linked lipids, various ... Plasmids may be transferred between cells by physical contact, in a process that may be similar to bacterial conjugation.[130][ ... cell membranes are made of molecules known as phospholipids. These molecules possess both a polar part that dissolves in water ... The major structure in cell membranes is a double layer of these phospholipids, which is called a lipid bilayer. ...
Cell membrane. Ether-linked lipids, pseudopeptidoglycan. Ester-linked lipids, peptidoglycan. Ester-linked lipids, various ... Plasmids may be transferred between cells by physical contact, in a process that may be similar to bacterial conjugation.[132][ ... cell membranes are made of molecules known as phospholipids. These molecules possess both a polar part that dissolves in water ... The major structure in cell membranes is a double layer of these phospholipids, which is called a lipid bilayer. ...
1- Donor cell produces pilus. 2- Pilus attaches to recipient cell, bringing the two cells together. 3- The mobile plasmid is ... Kuehn, M. J.; Kesty, N. C. (2005). "Bacterial outer membrane vesicles and the host-pathogen interaction". Genes & Development. ... Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be ... Portions of the outer membrane pinch off, forming spherical structures made of a lipid bilayer enclosing periplasmic materials ...
This treatment dissolves cell membranes, and allows larger dye molecules into the cell's interior. ... it will accumulate in lipid globules inside cells, staining them red. Nile red can be used with living cells. It fluoresces ... or organelles within individual cells.. In biochemistry it involves adding a class-specific (DNA, proteins, lipids, ... This is particularly useful for identifying endospore-forming bacterial pathogens such as Clostridium difficile. ...
... examples of molecules and ions that must efficiently cross the plasma membrane but to which the lipid bilayer of the membrane ... Oxygen binds with red blood cells in the blood stream. The oxygen affinity with hemoglobin on red blood cell surfaces enhances ... Non-polar molecules, such as retinol or lipids, are poorly soluble in water. They are transported through aqueous compartments ... Bauer & Metzler (2013)[4] therefore carried out an experiment using a bacterial genome in which they investigated the average ...
... s or haemolysins are lipids and proteins that cause lysis of red blood cells by disrupting the cell membrane. Although ... and small organic molecules. Rapid discharge of vital molecules such as ATP, dissipation of the membrane potential and ion ... Hemolysins may also mediate bacterial escape from host cells. Regulation of gene expression[edit]. The regulation of gene ... These subunits are attached to the target cells, the way we have already explained, and extend the lipid bilayer, forming the ...
phagocytic vesicle membrane. • Golgi apparatus. • membrane. • intrinsic component of plasma membrane. • cell membrane. • Toll- ... and T cells, including Tregs (CD4+CD25+ regulatory T cells). In some cases, it occurs in a heterodimer (combination molecule), ... response to bacterial lipoprotein. • negative regulation of cell proliferation. • response to toxic substance. • response to ... TLR2 resides on the plasma membrane where it responds to lipid-containing PAMPs such as lipoteichoic acid and di- and tri- ...
Cell adhesion molecules allow cells to identify each other and interact. For example, proteins involved in immune response. ... interaction by a covalently bound membrane lipid (lipidation) 4. electrostatic or ionic interactions with membrane lipids (e.g. ... Selkrig J, Leyton DL, Webb CT, Lithgow T (2014). "Assembly of β-barrel proteins into bacterial outer membranes". Biochimica et ... Main article: Peripheral membrane protein. Peripheral membrane proteins are temporarily attached either to the lipid bilayer or ...
Alum adheres to the cell's plasma membrane and rearranges certain lipids there. Spurred into action, the DC picks up the ... that are expressed on the membranes of leukocytes including dendritic cells, macrophages, natural killer cells, cells of the ... components of bacterial cell walls, and endocytosed nucleic acids such as double-stranded RNA (dsRNA), single-stranded DNA ( ... Monophosphoryl lipid A (MPL), a detoxified version of Salmonella minnesota lipopolysaccharide, interacts with TLR4 to enhance ...
... lipids, and other components into the cell membrane. Vesicles containing these membrane components fully fuse with and become ... are used by all cells because most chemical substances important to them are large polar molecules that cannot pass through the ... The periplasm is pinched off as bacterial outer membrane vesicles (OMVs) for translocating microbial biochemical signals into ... the term priming has been used to include all of the molecular rearrangements and ATP-dependent protein and lipid modifications ...
Lipids And Membranes è un di Geiger Otto (Curatore) edito da Springer a marzo 2019 - EAN 9783319504315: puoi acquistarlo sul ... Regulation of Membrane Lipid Homeostasis in Bacteria upon Temperature Change.- Role of Lipid Domains in Bacterial Cell ... All cells are delimited by a lipid membrane, which provides a crucial boundary in any known form of life. Readers will discover ... Formation of Lipochitin Oligosaccharide Signaling Molecules.- Functional Roles of Individual Membrane Lipids in Bacteria, ...
Thereby insight could be gained into the fundamentals of bacterial cell division and the innateimmune system. ... We found that the triplet state could also be used to probe low frequency interactions in membranes down to a single molecule ... 1. Fluorescence Studies of Membranes -- Proteins and Lipids, their Dynamics and Interactions. Öppna denna publikation i ny flik ... was found to increase the possibility to quantitatively analyse protein-protein interactions in the membrane of living cells. ...
Find out information about cell membrane. The membrane that surrounds the cytoplasm of a cell; it is also called the plasma ... membrane or, in a more general sense, a unit membrane. This is a very... Explanation of cell membrane ... The different lipid molecules are not equally distributed on both sides of the bilayer. The amino lipids, glycolipids, and ... The plasma membrane contains numerous receptor molecules that are involved in communication with other cells and the outside ...
But this enzyme is promiscuous in the extreme. It can produce lipids that, in bacterial cells, for example, require many ... If the enzyme can incorporate this buffer molecule as a lipid head group, what else could it do? As it turned out, the enzyme ... The lipids that form the cell membrane of archaea are structurally different from those in the other two domains of life, ... Archaeal enzyme that produces membrane lipids is spectacularly promiscuous. IMAGE: This illustration shows the production of ...
... are organic small molecules, that are usually hydrophobic or amphiphillic. This group includes fat, fatty acids, waxes, ... Lipids are the main structural component of biological membranes of all cells. As such bacterial lipid structures and ... Lipids. Lipids are organic small molecules, that are usually hydrophobic or amphiphillic. This group includes fat, fatty acids ... It induces cell death of F-11 murine neuroblastoma and apoptosis in U-87 human astrocytoma cells... ...
A method for modulation of plasma membrane associated Human Leukocyte Elastase (HLE) to inflammatory states by interaction of ... cellular organelles or their corresponding membranes; charged molecules associated with lipids or modified lipids; charged ... is involved in plasma membrane events during stimulation of immune cells, (Bristow and Flood, T Cell Antigen Immune Complexes ... Moreover, plasma membrane-associated HLE interactive peptides can be used as antagonists for HLE associated with lipid moieties ...
The lipid anchor attaches lipoproteins to the cytoplasmic membrane and prevents their release from the bacterial cell envelope ... a molecular mechanism that explains how cytoplasmic and membrane-embedded bacterial proteins can be released by bacterial cells ... TLR2 senses bacterial lipoproteins, the characteristic lipid anchor of which is absent from human molecules. S. aureus uses a ... The presence of membrane lipids is a hallmark for MVs. Although microscopically, more MVs are visible in wild-type than in PSM ...
... fast and cost-effect method for investigation of the membrane binding properties of this important class of molecules. ... AA139 was found to bind exclusively to anionic membranes with moderate affinity (Kd ~ low uM), and was found to have a lipid ... Here, we investigate the lipid binding properties of two membrane-active peptides, VSTx1, a well characterized ion-channel ... Here, we investigate the lipid binding properties of two membrane active peptides, VSTx1, a well characterised ion-channel ...
Teixeira, V.; Feio, M.J.; Bastos, M. Role of lipids in the interaction of antimicrobial peptides with membranes. Prog. Lipid ... albicans cells [55], whereas most AMPs kill the bacteria through direct interaction with the bacterial membrane. It has been ... Cell. 2004, 15, 4490-4499. [Google Scholar] [CrossRef]. *Bhattacharya, A.; Datta, A. Effect of cyclic AMP on RNA and protein ... The peptides adsorb and align in parallel to the surface of bacterial membranes, then the membranes are collapsed into micelle- ...
Antibiotics can prevent bacterial growth by inhibiting the synthesis of target biomolecules in bacteria, including the cell ... and interactions with cytosolic molecules (lipids, proteins, DNA, etc.). ... Nano-antibacterial agents kill bacteria through membrane destruction, oxidative stress response, ... Nano-antibacterial agents represent a new strategy for bacterial treatment. Compared with antibiotics, nano-antibacterial ...
Archaebacteria have lipids in their cell membranes. They are self-possessed of branched hydrocarbon chains, linked to glycerol ... The cells consist of a thick cytoplasm that includes all the compounds and molecules needed for metabolism and nutrition. Their ... These archaeas have a unique tetraether lipid monolayer membrane that is not acid labile. This unique membrane structure is ... During this process, the bacterial DNA replicates. The cell wall pinches off in the center, due to which the organism is ...
... creating gaping holes that allow molecules crucial for cell function to leak out. ... selectively kills cancer cells without harming normal cells. MP1 interacts with lipids that are abnormally distributed on the ... "Cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anticancer drugs," ... MP1 acts against microbial pathogens by disrupting the bacterial cell membrane. Serendipitously, the antimicrobial peptide ...
The bacterial cell membrane is usually viewed as a matrix in which membrane protein and lipid molecules are homogeneously ... and cells are therefore faced with the problem of ensuring the supply of appropriate lipids at the division site (40). The ... subtilis cells (22) and the suggested lateral heterogeneity of lipid molecules in bacterial membranes prompted us to examine ... since it has been suggested that lipid molecules are heterogeneously distributed in several bacterial membranes (11). We thus ...
Protein and Lipid Motifs Regulating Lipid Traffic in Membrane Biogenesis. Geoffrey Chang, The Scripps Research Institute, USA ... role of lipid domains in bacterial and viral pathogenesis; signal transduction from lipid domains; mechanisms of protein/lipid ... Mechanisms of Protein/Lipid Sorting by Lipid Domains/Role of Lipids in Protein Sorting/Intracellular Traffic of Lipid Domains ... Dynamics of Lipid Rafts at the Cell Surface. Akihiro Kusumi, Kyoto University, Japan Calcium Signaling Induced by Transient ...
Cells and subcellular compartments are separated from the external milieu by lipid membranes with protein molecules inserted ... Microbial biodiversity at the structural level: Composition of the average bacterial cell and basic bacterial cell structure. ... c. Sidedness and asymmetry of lipids: dynamics and phases.. d. Pointers to membrane lipid metabolism: phospholipases and ... Functional Geography of Cells: Introduction to Cell Organisation, Variety and Cell Membranes. Molecular Traffic in Cells. ...
"Early cell-autonomous accumulation of neutral lipids during infection promotes mycobacterial growth." Plos One 15, no. 5 (2020 ... "Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells." Plos One 9, no. 9 (2014): ... "Mycobacteria manipulate macrophage recruitment through coordinated use of membrane lipids." Nature 505, no. 7482 (January 9, ... In addition, zebrafish larvae are remarkably permeable to small molecules, providing a platform for whole-animal ...
Figure 7 Remaining panel: schematic of a whole bacterial cell model. Protegrin pores (in red within the orange cell membrane) ... A hypothesis would be that the lipid membranes of varied bacteria have got different compositions of lipid molecules that ... weve constructed a more substantial range model that produces the time-dependent ion focus in bacterial cells [10]. This model ... for different surface densities denotes that surface densities are defined based on the total area covered by lipids (as ...
The property of lipid is that to prevent the entry of water into the cell wall of the bacteria and act as hydrophobic bacterial ... The bacterial cell membrane lysed by functionalized nanomaterial, which act as a powerful tool. In early research, it has been ... In the deep orientation of cell wall contain fluid mosaic module contain two lipids layers consistent of liposaccharide in ... The field of nanotechnology research and innovation related material and devices at the level of atom and molecules. ...
... bacterial plasma membrane d. membrane of mitochondria is about 1 to 4 µ this., You may also like: cell and Molecular Biology ... A DNA molecule replicates to form two identical copies of itself. b. Endoplasmic Reticulum 19. Nebenkern of insect sperm cells ... Tay-sach syndrome is an autosomal genetic disorder due to the defect in membrane lipids turnover in the cell. 1. (c) ... Outer membrane contain more proteins/lipid ratio (by weight) than inner membrane d. Many porin proteins which are structurally ...
... such as lipids, cell membranes etc. Vitamin E, along with other anti-oxidants donates an electron to the free radical, thus ... In older horses fed vitamin E at 15 IU/kg of body weight, the bacterial killing ability of specific immune cells was increased ... These are essentially molecules which are missing an electron, making them highly reactive. This is an unstable condition and ... may increase the need for anti-oxidants in the body to prevent lipid perodixation. Thankfully, many sources of PUFAs may be ...
... damage/protection is based on a phospholipid liposome system that signals the membrane rupture caused by photo-induced lipid ... PEs are usually selected based on their antioxidant capacity for reducing the damage in lipids and proteins, which are key ... molecules in the maintenance of skin homeostasis and hair integrity. Interestingly, biomolecules that do not have any ... Percentage levels of membrane damage/protection are calculated by comparing the CF fluorescence level of DMMB-liposomes in the ...
Several membrane-perturbing agents extract lipids from membranes and, in some cases, this lipid efflux is lipid specific. In ... Determining the Influence of Small Molecules on Hypoxic Prostate Cancer Cell (DU-145) Viability Using Automated Cell Counting ... Cell Biology. Quantitative Measurements of HIV-1 and Dextran Capture by Human Monocyte-derived Dendritic Cells (MDDCs) Authors: ... The methods presented here can be adapted to measure a variety of substrates transported into any bacterial or fungal cell via ...
Stem Cell Differentiation *Stem Cell Proliferation *Stem Cell Signaling *Stem Cells *Steroid Hormone Receptors ... domains within 15 mammalian proteins termed StarD1-StarD15 are lipid-binding domains implicated in the intracellular lipid ... to modulation of sphingolipid metabolism and these bioactive lipids may function as mediators for increased risk of metabolic ... A protease K security assay indicated the fact that mitochondrial StarD7 was from the external mitochondrial membrane. The ...
Other molecules have a weaker SOD-like capacity, including glutathione peroxidase, and even hemoglobin in red blood cells. ... or from a poor liver metabolism that is supposed to control and regulate the lipid metabolism. Oxidized lipids are a key part ... and aid regeneration of Vitamin E tocopherols in cell membranes. This form of enhanced CoQ10 is also found to be more ... such as bacterial infections, candida species, etc. that penetrate deep into our tissues and cells. Superoxides, though, may ...
... as well as through damage to the cell membrane through lipid oxidation. This can result in both cell damage and cell death, as ... Inflammatory signals can then recruit mast cells, T cells, and leukocytes from the blood. These subsequently induce release of ... Urea is a polar, hygroscopic molecule which arises in the skin due to the breakdown of the above-mentioned protein filaggrin.6 ... Such emollients are generally formulated with an oily phase to restore lipids in epidermal layers and improve skin barrier ...
... or the cell membrane. Altogether, the damage to cells caused by free radicals is known as oxidative stress. The free radical ... A polysaccharide is a carbohydrate whose molecules consist of a number of sugar molecules bonded together. Polysaccharides are ... The lipid barrier of the cornea is strengthened, making shea butter ideal for the care of dry, atopic and damaged skin. It is ... Ceramides are lipids (fats) that are found naturally in high concentrations in the uppermost layers of skin. They make up over ...
It has a lipid-containing cell membrane made from glycerol ester lipids. They are characterized by a lack of a nuclear membrane ... Small molecules can diffuse through the cell wall, but larger molecules and ions require carrier proteins and channel proteins ... Similar to the other genetic material, the plasmids can be transferred to daughter cells during replication. They are the DNA ... Many moves about using flagella, but some are nonmotile or rely on bacterial gliding. ...
Measuring the Release of Fluorescein from MscL-Loaded Liposomes with Stressed Lipid Bilayers. CAMBRIDGE: CELL PRESS. ... Morphological aspects of in cubo membrane protein crystallisation. Biophysical Chemistry: Membranes and Proteins. (pp. 221-236 ... Banks, J. E., Rothnagel, A.R. and Hankamer, B. (2003). Automatic particle picking of biological molecules imaged by electron ... The structure of bacterial RNA polymerase in complex with the essential transcription elongation factor NusA. EMBO Reports, 10 ...
Cell membranes are made up of lipid bilayers. Lipids have heads and tails, and in the bilayer the tails of the top layer and ... These enzymes pass out of a bacterial cell. Lastly, some proteins have to make their way into the membrane of the cell, and, as ... "It is such a complex molecule, and it has such a central role in the cell and in life," responds Frank when asked why this ... Schultens main goal in his professional life has been to understand living cells. But a cell is a complex entity that involves ...
Twenty nanosecond molecular dynamics (MD) simulation of a fully hydrated tetramer of AqpM embedded in a lipid bilayer permitted ... Recently, the identification and characterization of a number of archaeal and bacterial aquaporins suggested the existence of a ... These channels, allow the passive but selective movement of water and other small neutral solutes across cell membranes. ... Water molecules above and below the membrane are represented as a transparent solid surface. The single file of water molecules ...
The mRNA molecule itself is too big to get through a cells membrane easily. ... Lipid nanoparticles, or LNPs, are tiny balls of layered lipids, or fats, ... RNA that hangs around outside of our cells can also be a remnant of a cell ... but not enough that you could just throw it at cells and hope for the best. ...
Outside the cells, the LNPs form a stable spherical structure that locks in their contents. When they are inside a cell, the ... Also present are polyethylene glycol, and yes, even some cholesterol - which has a normal role in lipid membranes to make them ... have developed unique nanoparticles comprised of lipids - fat molecules - that can package and deliver gene editing machinery ... Bacterial cells lacking the long form tracrRNA were cultured in the laboratory for three days and compared with similarly ...
Know the function of and be able to label any cell diagram with the following organelles cell wall plasma membrane ribosome ... How do bacterial cells differ from other types of cells How are chickenpox amp shingles alike Why do people get the flu more ... You ll learn about water s role as the basis of life and the functions of macromolecules like lipids and proteins. We provide ... Label the parts of the ATP molecule using the word bank. 4000 Fax 815. Biology. Maybe you have knowledge that people have see ...
Prokaryotic cells lack a nuclear membrane so DNA is unbound within the cell; eukaryotic cells have nuclear membranes. ... Cell contents are contained within a cell surface membrane that contains proteins and a lipid bilayer. ... The functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules. This energy ... For branching of Bacteria phyla, see Bacterial phyla.. The most commonly accepted location of the root of the tree of life is ...
... but the cellulose in their cell wall makes it hard to access the critical molecules inside and convert them to biogas. In the ... fructose fruit FT-SKA fuel fuel additives fuel cells fuel economy fuel efficiency fuel injection fuel mixtures fuel molecules ... Are Bacterial Probiotics a Game-Changer for the Biofuels Industry?. (Biofuels International) In a study recently published in ... Changing Carbohydrates into Lipids for Microalgae Biofuels. (Kobe University/Phy.Org) A cross-institutional collaboration has ...
Proliferating cells require not only ATP but also nucleotides, fatty acids, membrane lipids, and proteins, and a reprogrammed ... The increased nutrient uptake can then support the anabolic requirements of cell growth: mainly lipid, protein, and nucleotide ... 2007) have reported that treating cancer cells with dichloroacetate (DCA), a small molecule inhibitor of pyruvate dehydrogenase ... allows communication between dispersed gram-positive bacteria and thus coordinated behavior of widely dispersed bacterial ...
... functionalized red blood cell membranes for molecule encapsulation Cerebellar neurodynamics predict decision timing and outcome ... using coupled UPLC-MS Lipid bodies containing oxidatively truncated lipids block antigen cross-presentation by dendritic cells ... diabetic hyperglycemia Predicting bacterial infection outcomes using single cell RNA-sequencing analysis of human immune cells ... beta cell G1/S molecule cell cycle atlas Cytoplasmic-nuclear trafficking of G1/S cell cycle molecules and adult human beta cell ...
To our knowledge, this is the first evidence of a bacterial cell with differentially regulated domains containing unique ... Title: Coarse-Grained Simulations of Nicotinic Acetylcholine Receptors in Complex Mixed Membranes: Embedded Lipids and Domain ... Organization of nAChRs, including parti- tioning behavior in membranes containing distinct lipid domains, is poorly ... Abstract: Metabolism is the set of enzymatic reactions that cells use to generate energy and biomass. Interestingly, recent ...
Tiebe M, Lutz M, Senyilmaz Tiebe D, Teleman AA (2019) Crebl2 regulates cell metabolism in muscle and liver cells. Sci Rep 9: ... Extraction and liposome reconstitution of membrane proteins with their native lipids without the use of detergents. Sci Rep 8: ... Quantifying small molecule phenotypic effects using mitochondrial morpho-functional fingerprinting and machine learning. Sci ... Targeting cPLA2 derived lipid hydroperoxides as a potential intervention for sarcopenia. Sci Rep 10:13968.. 2020. ...
Patil, J., Kumar, N., Swamy, R. S., DSouza, M. R., Guru, A. & Nayak, S. B., 2014, In: Anatomy and Cell Biology. 47, 2, p. 135- ... 7-Ketocholesterol induces P-glycoprotein through PI3K/mTOR signaling in hepatoma cells. Wang, S. F., Chou, Y. C., Mazumder, N. ... 6b,11b-Dihydroxy-6b,11b-dihydro-7H-indeno[1,2-b]naphtho[2,1-d]furan-7-one (DHFO), a small molecule targeting NF-κB, ... A 10 Year clinical, laboratory and arthroscopic data analysis of bacterial septic arthritis of adult native knee: A hospital- ...
When the mitochondria do not work optimally, toxic lipid metabolites can accumulate in the liver that destroy liver cells, lead ... Increased blood lipids and chronic inflammation of the blood vessels lead to cardiovascular problems. The liver and kidneys are ... The mitochondria, which are tiny energy packages in each cell, are reduced in number, which causes a loss of energy. There is ... The amyloid-beta precursor protein is important for normal membrane function in the brain. It also has a very important ...
Patil, J., Kumar, N., Swamy, R. S., DSouza, M. R., Guru, A. & Nayak, S. B., 2014, In: Anatomy and Cell Biology. 47, 2, p. 135- ... 7-Ketocholesterol induces P-glycoprotein through PI3K/mTOR signaling in hepatoma cells. Wang, S. F., Chou, Y. C., Mazumder, N. ... 6b,11b-Dihydroxy-6b,11b-dihydro-7H-indeno[1,2-b]naphtho[2,1-d]furan-7-one (DHFO), a small molecule targeting NF-κB, ... A 10 Year clinical, laboratory and arthroscopic data analysis of bacterial septic arthritis of adult native knee: A hospital- ...
Patil, J., Kumar, N., Swamy, R. S., DSouza, M. R., Guru, A. & Nayak, S. B., 2014, In: Anatomy and Cell Biology. 47, 2, p. 135- ... A 10 Year clinical, laboratory and arthroscopic data analysis of bacterial septic arthritis of adult native knee: A hospital- ... 3-level Box-Behnkenoptimization of hexavalent chromium reduction by chromate resistant Trichoderma asperellum cells from ... Lipids 100% * Cooking 87% * Biodiesel 78% * Characterization (materials science) 65% * Lipid 51% ...
In turn, the plant provides its fungi with sugars for food and lipids which form the structure of its cell membranes. According ... The method used by Pfizer and Moderna uses a "lipid nanoparticle." Their vaccines mix the RNA with lipid molecules. The "lipid ... Syringafactin, is formed on the outside of the bacterial cell and is not itself toxic to the slime mold. But when Paenibacillus ... signaling between immune cells and cancer cells, and the prevention of programmed cell death (a process in which cells destroy ...
Kimkes, T.E.P. (2012) Targeting of Outer Membrane Proteins from the Inner to the Outer Membrane: the Role of the Periplasmic ... Jansma, A. (2012) Producing large quantities of red blood cells from stem cells for transfusion purposes. Bachelors Thesis, ... Blijleven, J.S. (2012) Design and Optimisation of a Lens System for the Transport and Separation of Slow Molecules. Bachelors ... Eising, S. (2012) Clickable lipids. Masters Thesis / Essay, Chemistry. Ekkers, D (2012) Evolution experiments in B. subtilis: ...
  • The Biosynthesis and Evolution of Archaeal Membranes and Ether Phospholipids. (
  • 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. (
  • In healthy cell membranes, phospholipids called phosphatidylserine (PS) and phosphatidylethanolamine (PE) are located in the inner membrane leaflet facing the inside of the cell. (
  • These results suggest that phospholipids are produced mostly in the septal membranes and that CL and PE are kept from diffusing out to lateral ones. (
  • The existence of heterogeneities in the lateral distribution of phospholipids and glycolipids was first revealed by a photo-cross-linking experiment in the membrane of the gram-positive bacterium Micrococcus luteus ( 60 ). (
  • In Escherichia coli membranes, application of the lipophilic fluorescent styryl dye FM4-64 has suggested laterally uneven distribution of phospholipids ( 16 ). (
  • Lipids also encompass molecules such as fatty acids and their derivatives (including tri- , di- , monoglycerides , and phospholipids ), as well as other sterol -containing metabolites such as cholesterol . (
  • In 1947, T. P. Hilditch divided lipids into "simple lipids", with greases and waxes (true waxes, sterols, alcohols), and "complex lipids", with phospholipids and glycolipids. (
  • These molecules, which number in the thousands, include important natural products such as fatty acids, phospholipids, and sterols ( 1 ) and work at jobs as varied as forming the protective membranes that shelter cells from the outside world to acting as targets for receptors or second messengers in signal transduction cascades. (
  • Phospholipids are the fundamental building blocks of cellular membranes and are the major part of surfactant , the film that occupies the air/liquid interfaces in the lung. (
  • Phospholipids have many functions in biological systems: as fuels, as membrane structural elements, as signaling agents, and as surfactants. (
  • Phospholipids are the major lipid constituent in cell membranes, thus maintaining structural integrity between the cell and its environment and providing boundaries between compartments within the cell. (
  • Displays bactericidal activity against Gram-positive bacteria by directly hydrolyzing phospholipids of the bacterial membrane (By similarity). (
  • Phospholipases are a group of enzymes that hydrolyze phospholipids into fatty acids and other lipophilic molecules. (
  • Glycerophospholipids , also referred to as phospholipids , are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. (
  • All unit membranes consist of a bilayer of lipid molecules, the polar surfaces of which are directed outward and covered by at least one monolayer of nonlipid molecules on each side, most of which are protein, packed on the lipid bilayer surfaces and held there by various intermolecular forces. (
  • The segments of the polypeptide chains of these transverse proteins within the core of the lipid bilayer may form channels that provide low-resistance pathways for ions and small molecules to get across the membrane in a controlled fashion. (
  • The molecular composition of each lipid monolayer making up the lipid bilayer is different. (
  • Our approach is validated by first determining the thermodynamic parameters and binding interface of VSTx1 toward the lipid bilayer, which shows good agreement with previous studies using lipid micelles and liposomes. (
  • CL, in the presence of certain divalent cations, and PE have a propensity to form nonbilayer structures, which may introduce discontinuities in the bilayer membrane structure for dynamic membrane functions such as membrane fusion during cell division, formation of adhesion sites between the outer and the inner membranes, integration of proteins into the membrane, and stabilization of membrane proteins ( 10 ). (
  • Ion transport across the relatively impermeable lipid bilayer of the cell membrane is accomplished via membrane proteins known as ion channels, pumps and transporters. (
  • This is surprising insofar as they must somehow cross the hydrophobic lipid bilayer. (
  • Sphingolipids, occurring primarily in nervous tissue, are thought to form cholesterol-rich domains within lipid bilayer membranes that may be important to the functions of some membrane proteins. (
  • Membrane Vesicles, Nanopods and Nanotubes of Archaea. (
  • Outer Membrane Vesicles of Bacteria. (
  • Staphylococcus aureus has been described to liberate membrane vesicles. (
  • The composition, mode of release, and relevance for microbe-host interaction of such membrane vesicles have remained ambiguous. (
  • Here we demonstrate that PSM peptides promote the release of membrane vesicles from the cytoplasmic membrane of S. aureus via an increase in membrane fluidity, and we provide evidence that the bacterial turgor is the driving force for vesicle budding under hypotonic osmotic conditions. (
  • Intriguingly, the majority of lipoproteins are released by S. aureus as components of membrane vesicles, and this process depends on surfactant-like molecules such as PSMs. (
  • the amphiphilic nature of some lipids allows them to form structures such as vesicles , multilamellar/ unilamellar liposomes , or membranes in an aqueous environment. (
  • We investigated the vaccine-potential of native outer membrane vesicles with over-expressed factor H-binding protein (NOMV-fHbp), which targeted antigens in African meningococcal strains, and was combined with a MenA polysaccharide conjugate vaccine. (
  • Using surface plasmon resonance and leakage assays with model vesicles, we confirmed that Ctn(15-34) binds to and disrupts lipid membranes and also observed that Ctn(15-34) has a preference for vesicles that mimic bacterial or tumor cell membranes. (
  • The proteins then enter more vesicles, to be transported around the cell. (
  • 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. (
  • Bacteria (prokaryotes) do not contain such elaborate systems of internal membranes, but some have an external unit membrane separated from the plasma membrane by a special material called periplasm. (
  • How bacteria release lipoproteins and how these molecules reach TLR2 remain unknown. (
  • It describes a potential pathway for the transfer of hydrophobic bacterial lipoproteins, the major TLR2 agonists, from the cytoplasmic membrane of Gram-positive bacteria to the TLR2 receptor at the surface of host cells. (
  • Moreover, our study reveals a molecular mechanism that explains how cytoplasmic and membrane-embedded bacterial proteins can be released by bacterial cells without using any of the typical protein secretion routes, thereby contributing to our understanding of the processes used by bacteria to communicate with host organisms and the environment. (
  • Antibiotics can prevent bacterial growth by inhibiting the synthesis of target biomolecules in bacteria, including the cell wall, DNA and proteins. (
  • Both bacteria and archaea are enclosed in cell membranes. (
  • But unlike most bacteria, they have a single cell membrane that lacks a peptidoglycan wall and their genetic transcription and translation - the two central processes in molecular biology - do not show the typical bacterial features, but are extremely similar to those of eukaryotes. (
  • Both bacteria and eukaryotes have membranes composed mainly of glycerol-ester lipids, whereas archaea have membranes composed of glycerol-ether lipids. (
  • The determination of cell viability and the quality control of probiotics and consumer products that contain active bacteria is also possible using electromigration. (
  • 1 Thus, identification, characterization and monitoring of pathogenic bacteria and other microorganisms or living cells are very important in clinical diagnosis, analysis in the food industry and quality control of several processes. (
  • These bacteria escape early detection by innate immunity, an ability associated to the absence of marked pathogen-associated molecular patterns in the cell envelope lipopolysaccharide, lipoproteins and flagellin. (
  • We show here that, in contrast to the outer membrane ornithine lipids (OL) of other Gram negative bacteria, Brucella abortus OL lack a marked pathogen-associated molecular pattern activity. (
  • Bacteria , despite their apparent simplicity contain a well developed cell structure which is responsible for many of their unique biological properties. (
  • Because of the simplicity of bacteria relative to larger organisms and the ease with which they can be manipulated experimentally, the cell structure of bacteria has been well studied, revealing many biochemical principles that have been subsequently applied to other organisms. (
  • Perhaps the most elemental structural property of bacteria is cell morphology (shape). (
  • Bacteria generally form distinctive cell morphologies when examined by light microscopy and distinct colony morphologies when grown on Petri plates . (
  • Bacteria within the Deinococcus-Thermus group may also exhibit Gram positive staining behaviour but contain some cell wall structures typical of Gram negative organisms. (
  • Some bacteria convert nitrogen gas into complex compounds that can be used by other organisms and …Bacteria help ruminant animals, such as cattle, digest organic materials.Bacteria lack a membrane-bound nucleus and other internal structures and are therefore ranked among the unicellular life-forms called prokaryotes. (
  • Traditionally, all prokaryotic cells were called bacteria and were classified in the prokaryotic kingdom Monera. (
  • Bacteria and Archaea) are fundamentally different from the eukaryotic cells that constitute other forms of life. (
  • Raetz has made fundamental contributions to understanding how these building blocks of biological membranes are assembled, particularly in bacteria. (
  • In this study we investigated the importance of lipid raft formation in the innate immune recognition of bacteria using biochemical and fluorescence imaging techniques. (
  • The main bacterial mode of living in an infected wound is biofilm, which can be defined as a confluent community of adherent bacteria characterized by high cell densities and encased in an extracellular polymeric matrix that acts as physical barrier for biological and pharmaceutical antimicrobials [ 4 , 5 ]. (
  • The specific molecules of interest are evolution-tested classes of membrane peptides, proteins, and lipids that act together on drug resistant bacteria, persister cells, biofilms, and tumors, and elicit immunomodulatory effects on host cells. (
  • Sugar moieties are found in both the proteins and lipids of the outer half of the unit membrane, but not on the inside next to the cytoplasm. (
  • One notable example is the dynamics of proteins and lipids in cellular membranes and their organization into nanodomains, so-called "lipid rafts" ( 8 - 12 ). (
  • Lipid Intermediates in Bacterial Peptidoglycan Biosynthesis. (
  • Modeling Lipid Metabolism in Yeast. (
  • The functions of lipids include storing energy, signaling , and acting as structural components of cell membranes . (
  • Lipids are the main structural component of biological membranes of all cells. (
  • The lipid composition of the cellular membrane plays an important role in a number of biological processes including the binding of membrane-active peptides. (
  • Cell biological, biochemical and clinical topics are included in this book, which serve to emphasize the acknowledged and important benefits to be gained from the study of cholesterol and cholesterol-binding proteins within the biomedical sciences and the involvement of cholesterol in several clinical disorders. (
  • The fatty acid structure is one of the most fundamental categories of biological lipids, and is commonly used as a building-block of more structurally complex lipids. (
  • Potassium channels - Integral membrane proteins that allow selective, diffusional passage of potassium ions across biological membranes. (
  • In animals and plants, fatty acids (FAs) are key molecules that participate in various biological processes. (
  • In plants, FAs and/or their derived metabolites are also recognized as signaling molecules central to various biological processes. (
  • The project features a concerted experimental effort between the College of William and Mary and the National Institute of Standards and Technology to develop and employ biophysical, biochemical, and biological methods to investigate the interplay of host defense mechanisms at biological membranes. (
  • Lipids are a diverse group of compounds that have many key biological functions, such as acting as structural components of cell membranes, serving as energy storage sources and participating in signaling pathways. (
  • [3] [4] The fatty acyl structure represents the major lipid building block of complex lipids and therefore is one of the most fundamental categories of biological lipids. (
  • Examples of glycerophospholipids found in biological membranes are phosphatidylcholine (also known as PC or GPCho, and lecithin ), phosphatidylethanolamine (PE or GPEtn) and phosphatidylserine (PS or GPSer). (
  • Upon absorbing a photon, the chromophore leaves the idle state and becomes excited, which allows its reaction with molecules in the biological environment leading to formation of photoproducts that will damage the tissue 6 . (
  • In Escherichia coli cells, however, no PE-rich domains were found. (
  • For example, Escherichia coli , an "average" sized bacterium with average cell length of ca. 1 µm has a cell volume of approximately 1 - 2 μm 3 . (
  • Therefore, a typical fully grown 1-liter culture of Escherichia coli (at an optical density of 1.0, corresponding to ca. 10 9 cells/ml) yields ca. 1 g wet cell mass. (
  • The N-terminal domain of the OmpA protein from Escherichia coli , consisting of 170 amino acid residues, is embedded in the outer membrane, in the form of an antiparallel β-barrel whose eight transmembrane β-strands are connected by three short periplasmic turns and four relatively large surface-exposed hydrophilic loops. (
  • The two-domain outer membrane protein OmpA of Escherichia coli is a well-established model for the study of membrane assembly in vivo ( 8 , 17 , 18 ) as well as in vitro ( 16 , 40 ). (
  • Wickner was right, so Raetz joined the team and began purifying and analyzing the enzymes involved in the production of membrane lipids in Escherichia coli . (
  • Both peptides were bactericidal, killing ∼90% of Escherichia coli and Pseudomonas aeruginosa cells within 90-120 and 5-30 min, respectively. (
  • Formation of Lipochitin Oligosaccharide Signaling Molecules. (
  • Lipids are organic small molecules, that are usually hydrophobic or amphiphillic. (
  • In general, when AMPs are folded in membrane mimetic environments, one side of AMPs is positively charged (mainly due to lysine and arginine residues) and the other side contains a considerable proportion of hydrophobic residues [ 1 , 2 , 5 , 6 ]. (
  • this arrangement confers the molecule with a polar , hydrophilic end, and a nonpolar, hydrophobic end that is insoluble in water. (
  • Formation of Bacterial Glycerol-based Membrane Lipids: Pathways, Enzymes, Reactions. (
  • [7] Although humans and other mammals use various biosynthetic pathways both to break down and to synthesize lipids, some essential lipids can't be made this way and must be obtained from the diet. (
  • The activity of the Cag-T4SS results in numerous changes in host cell biology including upregulation of cytokine expression, activation of proinflammatory pathways, cytoskeletal remodeling, and induction of oncogenic cell-signaling networks 5-8 . (
  • Winau and colleagues investigate three principal pillars of antigen presentation including helper molecules of processing (saposins, e.g.), entire presentation pathways (cross-priming, NKT cell activation), and the biology of antigen presenting cells (dendritic cells, stellate cells). (
  • Role of Lipids in the Eukaryotic Secretory Pathway. (
  • Eukaryotic cells are characterized by the triple-layered nature of the unit membrane. (
  • They are involved in the recognition of many ligands, e.g., small-molecule nutrients such as iron-siderophore complexes or sugars ( 13 , 15 ), toxic agents such as bacteriophages or colicins ( 3 , 14 , 30 ), and probably eukaryotic target cells for bacterial pathogens ( 2 , 24 , 33 ). (
  • All living organisms on Earth are made up of one of two basic types of cells: eukaryotic cells, in which the genetic material is enclosed within a nuclear membrane, or prokaryotic cells, in which the genetic material is not separated from the rest of the cell. (
  • However, their classification as Monera, equivalent in taxonomy to the other kingdoms-Plantae, Animalia, Fungi, and Protista-understated the remarkable genetic and metabolic diversity exhibited by prokaryotic cells relative to eukaryotic cells. (
  • Members of these two prokaryotic domains are as different from one another as they are from eukaryotic cells. (
  • Prokaryotic cells are defined by a much simpler design than is found in eukaryotic cells. (
  • The most apparent simplification is the lack of intracellular organelles, which are features characteristic of eukaryotic cells. (
  • In addition, prokaryotic cells are usually much smaller than eukaryotic cells. (
  • Prokaryotic and eukaryotic cells differ in many other ways, including lipid composition, structure of key metabolic enzymes, responses to antibiotics and toxins, and the mechanism of expression of genetic information. (
  • In addition to serving as a primary component of cellular membranes and binding sites for intra- and intercellular proteins, some glycerophospholipids in eukaryotic cells, such as phosphatidylinositols and phosphatidic acids are either precursors of, or are themselves, membrane-derived second messengers. (
  • Eukaryotic Cells. (
  • Where as, eukaryotic cells are larger and more complex e.g. animal and plants. (
  • In eukaryotic cells, the protein threads are arranged as microfillaments and microtubules. (
  • The innate immune system uses Toll-like receptor (TLR) 2 to detect conserved bacterial lipoproteins of invading pathogens. (
  • The innate immune system uses pattern recognition receptors (PRRs) such as the Toll-like receptors (TLRs) to detect conserved microbe-associated molecular pattern molecules (MAMPs) as a hallmark for the presence of invading pathogens ( 1 ). (
  • He is especially interested in the role of lipids in Immunology, acting as antigens or regulators of immune responses. (
  • Lipid domains are a class of membrane domains that compartmentalize signaling modules, regulate the transport of ions, molecules and macromolecular complexes to specific cellular sites, and spatially organize signal transduction in polarized cells. (
  • Fatty acid structure affects cellular activities through changes in membrane lipid composition and the generation of a diversity of bioactive derivatives. (
  • These membrane microdomains or lipid rafts are enriched in glycosphingolipids and cholesterol and have been implicated in cellular processes such as membrane sorting and signal transduction. (
  • We found that receptor molecules that are implicated in lipopolysaccharide (LPS)-cellular activation, such as CD14, heat shock protein (hsp) 70, 90, Chemokine receptor 4 (CXCR4), growth differentiation factor 5 (GDF5) and Toll-like receptor 4 (TLR4), are present in microdomains following LPS stimulation. (
  • Lipid raft integrity is essential for LPS-cellular activation, since raft-disrupting drugs, such as nystatin or MCD, inhibit LPS-induced TNF-α secretion. (
  • The plasma membrane of mammalian cells was once believed to be homogeneous, but it is now clear that it is discontinuous, containing numerous microdomains that are essential for cellular function. (
  • May contribute to lipid remodeling of cellular membranes and generation of lipid mediators involved in pathogen clearance. (
  • Lipid Metabolism in Microalgae. (
  • Players in the Nonpolar Lipid Game - Proteins Involved in Nonpolar Lipid Metabolism in Yeast. (
  • Archaea are similar to other prokaryotes in most aspects of cell structure and metabolism. (
  • At low surface area-to-volume ratios the diffusion of nutrients and waste products across the bacterial cell membrane limits the rate at which microbial metabolism can occur, making the cell less evolutionarily fit. (
  • Saposins are small proteins located in the lysosome and are involved in lipid metabolism. (
  • It can produce lipids that, in bacterial cells, for example, require many different enzymes. (
  • Green fluorescent protein fusions to the enzymes that catalyze the committed steps in PE synthesis, phosphatidylserine synthase, and in CL synthesis, CL synthase and phosphatidylglycerophosphate synthase, were localized mainly in the septal membranes in B. subtilis cells. (
  • To date, he has uncovered and characterized over 30 different enzymes responsible for synthesizing or modifying lipid molecules, including the entire nine-enzyme pathway for the biosynthesis of lipid A, an essential part of bacterial outer membranes and a significant contributor to the virulence of some microbes. (
  • In the wake of Doering's course, Raetz combined his interests in biology and chemistry to study enzymology, learning all of the intricate details about how enzymes bind to and act on their target molecules. (
  • Here, we investigate the lipid binding properties of two membrane-active peptides, VSTx1, a well characterized ion-channel inhibitor, identified from spider venom, that preferentially binds to anionic lipid mixtures, and AA139 an antimicrobial β-hairpin peptide with uncharacterised lipid binding properties, currently in pre-clinical development. (
  • The lipid binding properties of these peptides are elucidated using nanodiscs formed by both linear and circularized (sortase-mediated) forms of a membrane scaffold protein (MSP1D1ΔH5). (
  • Using these circularized nanodiscs, we are able to extract detailed thermodynamic data using isothermal titration calorimetry (ITC) as well as atomic resolution mapping of the lipid binding interfaces of our isotope labeled peptides using solution-state, heteronuclear, nuclear magnetic resonance (NMR) spectroscopy. (
  • This represents a novel and general approach for elucidating the thermodynamics and molecular interface of membrane-active peptides toward flat lipid bilayers of variable composition. (
  • A major limitation in the characterization of membrane-active peptides is the lack of detailed thermodynamic, kinetic and structural information regarding their lipid interactions. (
  • Mechanisms of bacterial membrane permeabilization by crotalicidin (Ctn) and its fragment Ctn(15-34), antimicrobial peptides from rattlesnake venom. (
  • Studies of ζ potential at the bacterial cell membrane suggested that both peptides accumulate at and neutralize negative charges on the bacterial surface. (
  • Flow cytometry experiments confirmed that both peptides permeabilize the bacterial cell membrane but suggested slightly different mechanisms of action. (
  • Atomic force microscopy visualized the effect of these peptides on bacterial cells, and confocal microscopy confirmed their localization on the bacterial surface. (
  • We find that nanodiscs formed by circularized MSPs-in contrast to those formed by linear MSPs-are sufficiently stable under sample conditions typically used for biophysical measurements (including lipid composition, a range of buffers, temperatures and concentrations). (
  • Cancer therapies that attack the lipid composition of the cell membrane would be an entirely new class of anticancer drugs," says co-senior study author Paul Beales, of the University of Leeds in the UK. (
  • In this thesis, fluorescence spectroscopy was utilized to probe protein and lipid dynamics and interactions in their native, or close to native, environments. (
  • The bacterial cell membrane is usually viewed as a matrix in which membrane protein and lipid molecules are homogeneously distributed according to the widely known fluid mosaic model based on the diffusional mobility of membrane lipids ( 53 ). (
  • Lipid-protein Interactions Determining Membrane Fluidity in Prokaryotes and Eukaryotes. (
  • In prokaryotes , the primary function of the cell wall is to protect the cell from internal turgor pressure caused by the much higher concentrations of proteins and other molecules inside the cell compared to its external environment. (
  • This limits the movement of the chains).The membranes can exist as bilayers or monolayers. (
  • Since saposins are able to interact with lipid bilayers leading to membrane destruction, a recent project examines the possible antibiotic impact of saposins on bacterial cell walls. (
  • Ornithine Lipids and Other Amino Acid-containing Acyloxyacyl Lipids. (
  • Readers will discover significant chapters on microbial lipid-carrying biomolecules and lipid/membrane-associated structures and processes. (
  • Among these antibacterial mechanisms, this review summarizes the interactions between GO and the bacterial membrane, especially the significant role of MIEs, including redox reactions with biomolecules, mechanical destruction of membranes, and catalysis of extracellular metabolites. (
  • Barrel Pore-Forming Bacterial Toxins: Structural and Functional Aspects -- Cholesterol-Binding Toxins and Anti-cholesterol Antibodies as Structural Probes for Cholesterol Localization. (
  • As in other organisms, the bacterial cell wall provides structural integrity to the cell. (
  • However, it is an open question whether these surface-exposed loops also play an important structural role, e.g., by determining the membrane topology of the polypeptide chain. (
  • Although the term "lipid" is sometimes used as a synonym for fats , fats are a subgroup of lipids called triglycerides . (
  • Although the term lipid is sometimes used as a synonym for fats , fats are a subgroup of lipids called triglycerides and should not be confused with the term fatty acid . (
  • Cell-contact-dependent Outer Membrane Exchange in Myxobacteria. (
  • Role of the BAM Complex in Outer Membrane Assembly. (
  • The outer mitochondrial membrane is in this sense a membrane of the cell analogous to a smooth endoplasmic reticulum membrane, and the inner membrane of the mitochondrion is the plasma membrane of the included organism, which normally does not become continuous with the membrane of the cell. (
  • But in cancer cells, PS and PE are embedded in the outer membrane leaflet facing the cell surroundings. (
  • The Cag-T4SS is a macromolecular machine comprised of sub-assembly components spanning the inner and outer membrane and extending outward from the cell into the extracellular space. (
  • All 16 loop deletion mutants assembled into the outer membrane with high efficiency and adopted the wild-type membrane topology. (
  • These results represent a further step toward the development of artificial outer membrane proteins. (
  • The three-dimensional structure of its N-terminal membrane-embedded domain, which assembles into the outer membrane as efficiently as the full-length protein ( 36 ), has been solved at atomic resolution ( 31 ). (
  • This 170-residue protein domain resides in the outer membrane in the form of an eight-stranded antiparallel β-barrel (Fig. 1 ), a finding that is reminiscent of the porins which are also built up from antiparallel β-strands that are connected by relatively large and hydrophilic surface-exposed loops and short periplasmic turns ( 5 , 44 ). (
  • Systematic studies demonstrated that circularly permuted variants ( 20 ) and even split variants ( 21 ) of this protein domain could assemble into the outer membrane with high efficiency. (
  • Among the surface-exposed loops, some are very important for the function of outer membrane proteins. (
  • Whereas charge distributions of the extramembranous regions are crucial for the membrane topology of cytoplasmic membrane proteins ( 10 , 27 ), it is unknown whether the extramembranous regions of outer membrane proteins play a similar role. (
  • Many receptor molecules, particularly membrane proteins, are difficult to isolate because their stability is supported by their native membrane environments. (
  • It also has receptor molecules, which allow it to repond to chemical messengers. (
  • During endocytosis the membrane maintains its orientation, with its cytoplasmic surface remaining next to cytoplasm. (
  • The lipid anchor attaches lipoproteins to the cytoplasmic membrane and prevents their release from the bacterial cell envelope. (
  • The bacterial cell wall differs from that of all other organisms by the presence of peptidoglycan (poly- N -acetylglucosamine and N -acetylmuramic acid), which is located immediately outside of the cytoplasmic membrane . (
  • Lipid Rafts. (
  • Our results suggest that the entire bacterial recognition system is based around the ligation of CD14 by bacterial components and the recruitment of multiple signalling molecules, such as hsp70, hsp90, CXCR4, GDF5 and TLR4, at the site of CD14-LPS ligation, within the lipid rafts. (
  • Even though lipid rafts are known to exist, their physiological significance is not yet clear. (
  • Since CD14 is found in such microdomains on the cell surface, it is probable that the entire bacterial recognition system is based around the ligation of CD14 by bacterial components and the recruitment of multiple signalling molecules at the site of CD14-LPS ligation, within the lipid rafts. (
  • In order to test this hypothesis we investigated the existence of receptors identified as mediators of the innate immune recognition of LPS in lipid rafts. (
  • Using biochemical and fluorescence imaging techniques, we found that a complex of receptors is being formed upon LPS stimulation within the lipid rafts. (
  • The plasma membrane and the membranes making up all the intracellular membranous organelles display a common molecular architectural pattern of organization, the unit membrane pattern, even though the particular molecular species making up the membranes differ considerably. (
  • As such bacterial lipid structures and glycolipids can serve as pathogen-associated-molecular-patterns (PAMPs) and are recognized by our immune system. (
  • The purpose of this meeting is to bring together a diverse set of investigators with the goal of exploring the molecular basis of lipid domain function. (
  • Perhaps no scientist has contributed as much to the important field of lipid biochemistry in recent years as Chris Raetz, the George Barth Geller Professor for Research in Molecular Biology at Duke University Medical Center (Durham, NC). (
  • This paper adds new insights into the world of lipid biosynthesis at the molecular level and is just a small example of why another picky group, the National Academy of Sciences, elected Raetz in 2006. (
  • Molecular mechanism of vesicle division induced by coupling between lipid geometry and membrane curvatures. (
  • We investigated the effects of lipid geometry on vesicle division using coarse grained molecular dynamics simulations. (
  • En el trabajo se detalla a nivel molecular el mecanismo por el cual ambos péptidos ejercen su acción bactericida interaccionando con la membrana bacteriana. (
  • Owing to the lack of suitable noninvasive techniques to detect these nanodomains in living cells, their spatial extent has been estimated at somewhere in the range of 5-200 nm ( 17 ), that is between molecular dimensions and the resolution limit of conventional fluorescence microscopy. (
  • 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 position provides opportunities to interact with leading groups in the fields of solid-state NMR, neutron diffraction, molecular dynamics, chemical biology, biocatalysis, bacterial infections, G-protein coupled receptor activation of immune cells, and cancer imaging. (
  • The plasma membrane of cells is composed of lateral heterogeneities, patches and microdomains. (
  • The plasma membrane may become tucked into the cytoplasm and pinch off to make an isolated vesicle containing extracellular material by a process called endocytosis. (
  • Upon activation, stellate cells differentiate into myofibroblasts for production of extracellular matrix, leading to liver fibrosis. (
  • Secretory calcium-dependent phospholipase A2 that primarily targets extracellular lipids, exerting anti-inflammatory and immunosuppressive functions (PubMed:10455175, PubMed:10681567). (
  • In draining lymph nodes, selectively hydrolyzes diacyl and alkenyl forms of phosphatidylethanolamines, releasing omega-3 polyunsaturated fatty acids (PUFAs) such as eicosapentaenoate and docosahexaenoate that are precursors of the anti-inflammatory lipid mediators, resolvins (By similarity). (
  • Pro-resolution lipid mediators include four classes derived from cell membrane arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid (DHA) which comprise the lipoxins, protectins, resolvins and maresins (MaR) 14 . (
  • In general, pro-resolution lipid mediators are by definition known for reducing neutrophil recruitment toward the inflamed tissue and also stimulating non-phlogistic phagocytosis (efferocytosis) by macrophages without impairing bacterial killing 14 , 16 . (
  • The archaeal membranes consist of a glycerol-1-phosphate backbone with either linkages between glycerol and fatty acids. (
  • While all bacterial cell walls (with a few exceptions e.g. intracellular parasites such as Mycoplasma ) contain peptidoglycan, not all cell walls have the same overall structures. (
  • Examples of structures in this category are the digalactosyldiacylglycerols found in plant membranes and seminolipid from mammalian spermatazoa. (
  • It is small, hair-like structures found on the surface membrane of some animal cells. (
  • Other major lipid classes in the fatty acyl category are the fatty esters and fatty amides. (
  • We found that the triplet state could also be used to probe low frequency interactions in membranes down to a single molecule level and a theoretical model was developed that supported the observed interactions. (
  • Here, we present an optical single-molecule tracking approach that is capable of following the fast lipid movements with minimal invasion. (
  • The review also discusses in detail the physicochemical effect of GO on the bacterial membrane , such as phospholipid peroxidation, insertion, wrapping and the trapping effect, lipid extraction, and free radicals induced by GO. (
  • A study with pyrene-labeled phospholipid analogues has supported the heterogeneous distribution, suggesting a segregated distribution of phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) domains in bacterial membranes ( 59 ). (
  • The use of lipophilic fluorescent probes has visualized the uneven distribution of lipid domains in mycobacterial membranes ( 4 ). (
  • It has been previously reported that human leukocyte elastase (HLE) is involved in plasma membrane events during stimulation of immune cells, (Bristow and Flood, T Cell Antigen Immune Complexes Demonstrating Biologic & Proteolytic Activity , Int. Immunol. (
  • Recent studies have shown the importance of lipid raft formation in the acquired immune response. (
  • Although the importance of lipid raft formation for the acquired immune recognition is clear, the involvement of membrane microdomains in the innate immune response has not yet been investigated. (
  • NKT cells represent a lymphocyte subset implicated in immune regulation mainly through rapid burst of cytokines such as IFN-γ and IL-4 thereby imprinting downstream immune responses. (
  • During the resolution phase of acute inflammation drives docosahexaenoate-derived resolvin D1 synthesis, which suppresses dendritic cell activation and T-helper 1 immune response (By similarity). (
  • Via a mechanism independent of its catalytic activity, promotes differentiation of regulatory T cells (Tregs) and participates in the maintenance of immune tolerance (By similarity). (
  • So unlike for the latter, the membrane is resistent to antibiotics that target and prevent the synthesis of peptidoglycan wall. (
  • The Cag-T4SS is responsible for translocating CagA and peptidoglycan into host epithelial cells 5,6 . (
  • Peptidoglycan is responsible for the rigidity of the bacterial cell wall and for the determination of cell shape. (
  • The Gram positive cell wall is characterized by the presence of a very thick peptidoglycan layer, which is responsible for the retention of the crystal violet dyes during the Gram staining procedure. (
  • Pore formation is facilitated by the binding of nisin to lipid II, a membrane-bound peptidoglycan precursor, which is thought to function as a docking molecule rather than as a receptor. (
  • This combination of polar and nonpolar segments is termed amphiphilic, and the word describes the tendency of these molecules to assemble at interfaces between polar and nonpolar phases. (
  • In this sense the contents of intracellular organelles, such as the endoplasmic reticulum, Golgi apparatus sacs, nuclear membrane, lysosomes, peroxisomes, and secretion granules, are material of the outside world, since at some time the space occupied by this material may become continuous directly or indirectly with the outside world. (
  • Lipids as Receptors. (
  • The activity of natural killer (NK) cells is regulated by a fine-tuned balance between activating and inhibitory receptors. (
  • Ion channels regulate passage of ions like calcium, chloride, sodium, and potassium through cell membranes, in and out of cell organelles, and play a role in cell signaling. (
  • TRP channels can be gated by G protein-couple receptor (GPCR) signaling, lipids, ions, osmolarity, voltage or even hot or cold temperatures. (
  • The genetic material is segregated into a central region bounded by the nuclear membrane that is penetrated by many pores containing special proteins. (
  • Formed in only seconds, these large pores are big enough to allow critical molecules such as RNA and proteins to easily escape cells," Neto says. (
  • The dramatic enhancement of the permeabilization induced by the peptide in the presence of PE and the dimensions of the pores in these membranes was surprising. (
  • It is now known that nisin functions, at least in part, by the formation of pores in the bacterial cell membrane, with the interaction being largely dependent on the type of lipids present and, most importantly, the charge carried by those lipids ( 2 , 11 , 26 ). (
  • Oleoyl serinol is an analog of ceramide and an agonist of the cannabinoid receptor GPR119 that has an EC50 value of 12 µM for stimulating secretion of GLP-1 in mouse endocrine GLUTag cells. (
  • Potassium channels are essential for control of membrane potential, regulation of cell volume, and secretion of salt, neurotransmitters, and hormones. (
  • One virulence factor that has been associated with increased risk of gastric disease is the Cag-pathogenicity island, a 40-kb region within the chromosome of H. pylori that encodes a type IV secretion system and the cognate effector molecule, CagA 4,5 . (
  • The ability of dendritic cells to respond to the signals required for IL-1β secretion can be tested using a synthetic purine, R848, which is sensed by TLR8 in human monocyte derived dendritic cells (moDCs) to prime cells, followed by activation of the NLRP3 inflammasome with the bacterial toxin and potassium ionophore, nigericin. (
  • For a century, chemists regarded "fats" as only simple lipids made of fatty acids and glycerol (glycerides), but new forms were described later. (
  • Fatty acids , or fatty acid residues when they are part of a lipid, are a diverse group of molecules synthesized by chain-elongation of an acetyl-CoA primer with malonyl-CoA or methylmalonyl-CoA groups in a process called fatty acid synthesis . (
  • Exogenous application of various fatty acids to wild-type and JA-deficient mutants confirmed AA as the signaling molecule. (
  • These molecules consist of a polar or charged head group and a pair of nonpolar fatty acid tails, connected via a glycerol linkage. (
  • Two fatty acid chains, each typically having an even number of carbon atoms between 14 and 20, attach (via a dual esterification ) to the first and second carbons of the glycerol molecule, denoted as the sn1 and sn2 positions, respectively. (
  • Fatty acyls (including fatty acids ) are a diverse group of molecules synthesized by chain-elongation of an acetyl-CoA primer with malonyl-CoA or methylmalonyl-CoA groups. (
  • The preference of AA139 for anionic lipids supports a role for membrane binding in the mode-of-action of this peptide, which is also consistent with its higher inhibitory activity against bacterial cells compared to mammalian cells. (
  • When studying the enzyme that is responsible for producing cardiolipins in archaea (single-cell organisms that constitute a separate domain of life), biochemists at the University of Groningen made a surprising discovery. (
  • The lipids that form the cell membrane of archaea are structurally different from those in the other two domains of life,' Exterkate explains. (
  • Archaea are bound by a plasma membrane that is layered by pseudopeptidoglycans instead of peptidoglycans. (
  • IMPORTANCE Our study highlights the roles of surfactant-like molecules in bacterial inflammation with important implications for the prevention and therapy of inflammatory disorders. (
  • HIV disease progression, bacterial infections and autoimmune diseases), which are responsive/sensitive to such inflammation. (
  • and B. Contacting said plasma membrane lipid-associated Human Leukocyte Elastase (HLE), with said peptide antagonist under binding conditions so as to effect interaction of said antagonist and said plasma membrane lipid-associated Human Leukocyte Elastase (HLE), and thereby suppression of plasma membrane response to inflammation. (
  • Although the pathology of both these diseases is complex and involves many cell types, such as CD8 positive cells and macrophages, both conditions are predominantly characterized by neutrophilic inflammation. (
  • By utilizing a methodology based on fluorescently labelled antibodies, we were able to calibrate our FCCS system and provide quantitative data on a particular receptor interaction occurring in natural killer cells. (
  • A method for modulation of plasma membrane associated Human Leukocyte Elastase (HLE) to inflammatory states by interaction of HLE with an antagonist to inhibit HLE and thereby interruption in plasma associated events (e.g. (
  • It is another object of this invention to provide a method for modulation of plasma membrane-associated response to infection by interaction of HLE with an antagonist to inhibit HLE and thereby interruption in plasma associated events (e.g. response to inflammatory states, including HIV disease progression, bacterial infections and autoimmune diseases) that can result in infection or progression of a disease state. (
  • Bacterial resistance to antibiotics can be achieved by diverse routes including inhibition of the drug-target interaction, modification of the drug-binding site in target proteins, and efflux of the drug from target cells [ 10 ]. (
  • Knowledge of cholesterol and its interaction with protein molecules is of fundamental importance in both animal and human biology. (
  • Dual-color fluorescence cross-correlation spectroscopy (FCCS) was used to directly demonstrate a so-called cis-interaction between a member of the inhibitory NK cell receptor family Ly49 (Ly49A), and its ligand, the major histocompatibility complex (MHC) class I, within the plasma membrane of the same cell. (
  • For the Ly49A- MHC class I interaction it indicates that within a critical concentration range the local concentration level of MHC class I can provide a distinct regulation mechanism of the NK cell activity. (
  • 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. (
  • After characterizing the effects of incubation time and SMALP concentration on the activity of three distinct phages, we present evidence that the interaction between two model phages and SMALPs is specific to bacterial species and the phage receptor molecule. (
  • Previously, we have shown that its C-terminal fragment, Ctn(15-34), retains the antimicrobial and antitumor activities but is less toxic to healthy cells and has improved serum stability. (
  • Nonpolar Lipids in Yeast: Synthesis, Storage and Degradation. (
  • Type III Polyketide Synthases Responsible for Phenolic Lipid Synthesis. (
  • In addition, the binding of nisin to lipid II is responsible for a secondary mode of action, i.e., inhibition of cell wall synthesis ( 45 ). (
  • Functional Roles of Non-membrane Lipids in Bacterial Signaling. (
  • Role of Lipid Domains in Bacterial Cell Processes. (
  • Since cardiolipins are present in cell membranes of organisms from all domains of life, they are desired components of the synthetic cell. (
  • Application of the cardiolipin (CL)-specific fluorescent dye 10- N -nonyl-acridine orange has recently revealed CL-rich domains in the septal regions and at the poles of the Bacillus subtilis membrane (F. Kawai, M. Shoda, R. Harashima, Y. Sadaie, H. Hara, and K. Matsumoto, J. Bacteriol. (
  • The localization of the fluorescence thus evidently reflected the localization of PE-rich domains in the septal membranes. (
  • Similar PE-rich domains were observed in the septal regions of the cells of many Bacillus species. (
  • Staining with the cardiolipin (CL)-specific fluorescent dye 10- N -nonyl-acridine orange (NAO) has provided unequivocal visualization of CL-rich domains in E. coli membranes, which were located mostly in the septal regions and at the poles ( 33 , 34 ). (
  • We have used NAO staining to visualize CL-rich domains in Bacillus subtilis Marburg membranes and have shown that the CL-rich domains are localized clearly in the septal regions and at the poles ( 22 ). (
  • Technical aspects are given considerable emphasis, particularly in relation cholesterol reporter molecules and to the isolation and study of membrane cholesterol- and sphingomyelin-rich "raft" domains. (
  • Cell shape is generally characteristic of a given bacterial species, but can vary depending on growth conditions. (
  • However, cell-surface lipids are known to negatively influence catalytic activity (Bangalore and Travis, Comparison Of Properties OF Membrane Bound Versus or modulate such response to various disease states by control of HLE involvement in such processes. (
  • They arise when a lower number of fluorescent molecules undergo Brownian motion through a confocal detection volume. (
  • The sensitivity and time resolution allows also electron transitions within the fluorescent molecules to be probed. (
  • FCS can be extended to fluorescence cross-correlation (FCCS), to handle also a second type of fluorescent molecule, fluorescing with a different colour, and whose signal is cross-correlated with the signal from the first type of fluorescent molecules. (
  • 1 ms). The fluorescence signal during individual passages of fluorescent molecules through a spot of excitation light allows the sequential localization and thus spatio-temporal tracking of the molecule if its fluorescence is collected on at least three separate point detectors arranged in close proximity. (
  • Over the years, specific labeling of the cell's constituent parts with fluorescent markers has enabled deeper understanding in many areas of cell biology and allowed, for example, the spatio-temporal tracking of single particles ( 6 , 7 ). (
  • Nanoscale trapping of fluorescent lipid analogs in the plasma membrane of living cells is revealed and is consistent with the previous STED-FCS data. (
  • Here, it is shown that, in addition to its major contribution in responding to ethanol, pH, and hydrogen peroxide stresses, LisRK is involved in the ability of the cell to tolerate important antimicrobials used in food and in medicine, e.g., the lantibiotic nisin and the cephalosporin family of antibiotics. (