 Lipopolysaccharide (captions are in French) Lipopolysaccharide (LPS) is a large molecule consisting of a lipid and a polysaccharide (carbohydrate) joined by a covalent bond. Image File history File links No higher resolution available. ...
Image File history File links No higher resolution available. ...
In science, a molecule is a group of atoms in a definite arrangement held together by chemical bonds. ...
A polyunsaturated triglyceride. ...
Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ...
Lactose is a disaccharide found in milk. ...
Covalent bonding is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. ...
Functions
LPS is a major component of the outer membrane of Gram-negative bacteria, contributing greatly to the structural integrity of the bacteria, and protecting the membrane from certain kinds of chemical attack. LPS is an endotoxin, and induces a strong response from normal animal immune systems. Mitochondria structure : 1) Inner membrane 2) Outer membrane 3) Crista 4) Matrix The outer membrane refers to the outside membranes of Gram-negative bacteria, the chloroplast, or the mitochondria. ...
Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ...
Endotoxins are potentially toxic, natural compounds found inside pathogens such as bacteria. ...
A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ...
LPS acts as the prototypical endotoxin, because it binds the CD14/TLR4/MD2 receptor complex, which promotes the secretion of pro-inflammatory cytokines in many cell types, but specially in macrophages An "LPS challenge" in immunology is the exposing of the subject to an LPS which may act as a toxin. Endotoxins are potentially toxic, natural compounds found inside pathogens such as bacteria. ...
The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ...
Toll-like receptors (TLRs) are type I transmembrane proteins that serve as a key part of the innate immune system. ...
In biochemistry, a receptor is a protein on the cell membrane or within the cytoplasm or cell nucleus that binds to a specific molecule (a ligand), such as a neurotransmitter, hormone, or other substance, and initiates the cellular response to the ligand. ...
Inflammation is the first response of the immune system to infection or irritation and may be referred to as the innate cascade. ...
Cytokines are a group of proteins and peptides that are used in organisms as signaling compounds. ...
LPS also increases the negative charge of the cell membrane and helps stabilize the overall membrane structure. // The cell membrane (also called the plasma membrane or plasmalemma) is a semipermeable lipid bilayer common to all living cells. ...
Composition It comprises three parts: Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ...
The term Side chain can have different meanings depending on the context: In chemistry and biochemistry a side chain is a part of a molecule attached to a core structure. ...
Lipid A is a lipid component of a endotoxin held responsible for toxicity of Gram-negative bacteria. ...
Lipid A Lipid A contains unusual fatty acids (e.g. hydroxy-myristic acid) and is embedded into the outer membrane while the rest of the LPS projects from the surface. In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated. ...
Myristic acid, also called Tetradecanoic acid, is a common saturated fatty acid found in dairy products. ...
Core oligosaccharide Core oligosaccharide contains unusual sugars (e.g. KDO, keto-deoxyoctulonate and heptose). Magnification of grains of sugar, showing their monoclinic hemihedral crystalline structure. ...
A heptose is a monosaccharide with seven carbon atoms. ...
The core oligosaccharide is attached to lipid A, which is also in part responsible for the toxicity of gram-negative bacteria. Lipid A is a lipid component of a endotoxin held responsible for toxicity of Gram-negative bacteria. ...
O-antigen The polysaccharide side chain is referred to as the O-antigen of the bacteria. O side chain (O-antigen) is also a polysaccharide chain that extends from the core polysaccharide. The composition of the O side chain varies between different gram-negative bacterial strains. O side chains are easily recognized by the antibodies of the host, however, the nature of the chain can easily be modified by Gram-negative bacteria to avoid detection. The structure of the core and the O-antigen is often determined by methylation analysis or NMR-spectroscopy. An antigen is a molecule that stimulates an immune response. ...
An antigen is a molecule that stimulates an immune response. ...
Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ...
Each antibody binds to a specific antigen; an interaction similar to a lock and key. ...
Bacteria that are Gram-negative are not stained dark blue or violet by Gram staining, in contrast to Gram-positive bacteria. ...
Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ...
NMR may refer to: Nuclear magnetic resonance, a phenomenon involving the interaction of atomic nuclei and external magnetic fields Nielsen Media Research, a U.S. company which measures TV, radio and newspaper audiences This is a disambiguation page — a navigational aid which lists other pages that might otherwise share...
LPS modifications The making of LPS can be modified in order to present a specific sugar structure. Those can be recognised by either other LPS (which enables to inhibit LPS toxins) or glycosyltransferases which use those sugar structure to add more specific sugars.
Variability and effect upon specificity O-antigens (the outer carbohydrates) are the most variable portion of the LPS molecule, imparting the antigenic specificity. In contrast, lipid A is the most conserved part. However, —lipid A composition also may vary (eg in number and nature of acyl chains even within or between genera). Some of these variations may impart antagonistic properties to these LPS. For example Rhodobacter sphaeroides diphosphoryl lipid A (RsDPLA) is a potent antagonist of LPS in human cells, but is an agonist in hamster and equine cells.
It has been speculated that conical Lipid A (eg from E coli) are more agonistic, less conical lipid A like those of Porphyromonas gingivalis may activate a different signal (TLR2 instead of TLR4), and completely cylindrical lipid A like that of Rhodobacter sphaeroides is antagonistic to TLRs.[1][2] TLR-2 is the name for a biomolecule, which plays a role in the human immune system. ...
Functions LPS function has been under experimental research for several years due to its role in activating many transcription factors, which become active after stimulation with LPS. In molecular biology, a transcription factor is a protein that binds DNA at a specific promoter or enhancer region or site, where it regulates transcription. ...
LPS also produces many types of mediators involved in septic shock. Septic shock is a serious medical condition causing such effects as multiple organ failure and death in response to infection and sepsis. ...
Diversity Lipololysaccharide gene clusters are highly variable between different strains, subspecies, species of bacterial pathogens of plants and animals.[3][4]
References - ^ Netea M et al (2002). "Does the shape of lipid A determine the interaction of LPS with Toll-like receptors?". Trends Immunol 23 (3): 135-9. PMID 11864841.
- ^ Seydel U, Oikawa M, Fukase K, Kusumoto S, Brandenburg K (2000). "Intrinsic conformation of lipid A is responsible for agonistic and antagonistic activity". Eur J Biochem 267 (10): 3032-9. PMID 10806403.
- ^ Reeves P, Wang L (2002). "Genomic organization of LPS-specific loci". Curr Top Microbiol Immunol 264 (1): 109-35. PMID 12014174.
- ^ Patil P, Sonti R (2004). "Variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice". BMC Microbiol 4 (1): 40. PMID 15473911.
See also Endotoxins are potentially toxic, natural compounds found inside pathogens such as bacteria. ...
Glycosaminoglycans (GAGs) are long unbranched polysaccharides, made up of repeating disaccharides that may be sulphated (e. ...
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