Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chemical and serological investigations were carried out on lipopolysaccharides of 4 Salmonella S-forms and of 1 SR-mutant, extracted from bacteria at different ages of culture (early exponential to stationary growth phase). The results show that the fatty acid composition of Lipid A (lauric-, myristic-, palmitic-, and beta-hydroxy-myristic acids) does not undergo any significant change during the growth of the cultures. However, there are differences in the molar ratios of the fatty acids from strain to strain. In all phases of growth Lipid A is substituted by basaloligosaccharide, to the same extent, as can be seen from the constant ratios of beta-hydroxy-myristic acid: heptose. Serological experiments (haemagglutination inhibition tests, absorption of antibodies by LPS-coated erythrocytes) showed that in no case the basaloligosaccharide is completely substituted by O-specific chains and that basaloligosaccharide exhibits free R-antigen structures which are mainly of chemotypes Ra, Rb and Rc, for the SR-mutant only of types Ra and Rb. There is no demonstrable dependence upon the phases of growth. In the O-specific polysaccharide chains the sugars of the main chain and the side bound dideoxy sugars (abequose and tyvelose) show a constant 1:1 molar ratio in all phases. In the case of S. typhimurium, antigen factors 1, 4 and 12(2), the biosynthesis of which is controlled by modifying oaf genes and/or by a lysogenic phage, are of a somewhat weaker expression in the exponential phase than in the latter phases of growth. In the SR-mutant, lipopolysaccarides with (low) serological O1 and O12(2) activity are only extractable by the phenol/water method, but not by the PCP method. In three out of four S-forms, changes occur in the length of the O-specific polysaccharide chains, whereas the number of repeating units of the fourth strain remains almost unchanged. The lipopolysaccharides of the SR-mutant contain in all phases of growth about one repeating unit. In all strains the covering of the cell surface by lipopolysaccharide molecules changes during the course of growth, as can be seen by comparing the relative cell surface and the content of Lipid A fatty acids of the bacteria. Lipid A synthesis in the 4 S-forms is reduced in the exponential phase and/or in the phase of delayed growth acceleration. The extent of biosynthesis of the carbohydrate moiety of lipopolysaccharides is independent of that of Lipoid A. In the SR-mutant, Lipoid A and Polysaccharide are formed in increased amounts in the exponential growth phase.
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PMID:[Chemical and serological characterization of Salmonella lipopolysaccharides from different phases of growth (author's transl)]. 76 1

Lipopolysaccharides were isolated from six oral anaerobes(Va.Bg.Bf.Fn.Aa.Co.)by the hot phenol-water procedure and purified by PCP method.The six species can be all extracted their LPS with different yields (from 0.70 to 2.83% of cell dried weight).Comparable of LPS with the enterobacteriaceae(Sm.),they were the constructed with hexosamine,fatty acids and phosphorus etc.On the other hand,they showed much distinct differences from the enterobacterial LPS structure as follow:(1) 2-keto-3-deoxy-D-mannooctonate(KDO) was not detected by routine procedure.(2)The amount of heptose is reltively lower.(3) Methylated and branched fatty acids were detected.These chemical characteristics may relate to biological activities and pathogenic potential of LPS and bacteria themselves.
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PMID:[Chemical analysis of lipopolysac-charides derived from oral anacerobes] 1515 22