Biomaterial Database

Physical properties of short- and long-O-antigen-containing fractions of lipopolysaccharide from Escherichia coli 0111:B4. 1986

A A Peterson, and A Haug, and E J McGroarty

Aggregates of short- and long-chain O-antigen-containing fractions of lipopolysaccharide were analyzed by electron spin resonance probing to reveal differences in their physical properties. The fluidities of the lipid regions of the two fractions were quite similar, although the long-chain lipopolysaccharide aggregates appeared to be more hydrated as reflected by the polarity determined with a lipid probe. In contrast, the head-group region of the long-chain fraction was dramatically more mobile than that of the short-chain sample. The binding of polycations (e.g., polymyxin B, spermine) to lipopolysaccharide aggregates was measured by the partitioning of a cationic spin probe. Less probe was displaced from the long-chain fraction and unseparated lipopolysaccharide than from the short-chain fraction by the addition of cations, suggesting that the long O-antigen masks anionic sites on lipopolysaccharide. These results indicate that the aggregate shape and reactivity of lipopolysaccharide are affected by O-antigen length. Thus, the biological activity of lipopolysaccharide may be modulated directly by the presence of O-antigen and indirectly by the effects of O-antigen on the lipopolysaccharide aggregate structure.

UI	MeSH Term	Description	Entries
D008070	Lipopolysaccharides	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)	Lipopolysaccharide,Lipoglycans
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D004578	Electron Spin Resonance Spectroscopy	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.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D000942	Antigens, Bacterial	Substances elaborated by bacteria that have antigenic activity.	Bacterial Antigen,Bacterial Antigens,Antigen, Bacterial
D019081	O Antigens	The lipopolysaccharide-protein somatic antigens, usually from gram-negative bacteria, important in the serological classification of enteric bacilli. The O-specific chains determine the specificity of the O antigens of a given serotype. O antigens are the immunodominant part of the lipopolysaccharide molecule in the intact bacterial cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	O-Antigen,O-Specific Polysaccharides,O Antigen,O Antigen, Bacterial,O-Antigens,O-Specific Polysaccharide,Antigen, Bacterial O,Antigen, O,Antigens, O,Bacterial O Antigen,O Specific Polysaccharide,O Specific Polysaccharides,Polysaccharide, O-Specific,Polysaccharides, O-Specific