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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fatty acid composition of the lipid A moiety of the lipopolysaccharide and phospholipid fractions of Proteus mirabilis changed significantly on varying the growth temperature. A decrease in the growth temperature from 43 degrees C to 15 degrees C resulted in a decrease in the palmitic acid content of the lipopolysaccharide from 19.4% of total fatty acids at 43 degrees C to 1.4% at 15 degrees C, and by the appearance of an unsaturated fatty acid residue, hexadecenoic acid. Changes in the 3-hydroxy-myristic acid content of the lipid A were minimal. The decrease in the growth temperature also resulted in a decrease in the saturated fatty acid content of the phospholipid fraction, which was accompanied by an increase in their fluidity, as measured by the freedom of motion of spin-labeled fatty acids incorporated into dispersions made of the phospholipids. Nevertheless, the fluidity obtained with membrane phospholipids extracted from the cells grown at various temperatures were essentially the same when fluidity was determined at the growth temperature, supporting the hypothesis that variations in the fatty acid composition of membrane phospholipids serve to produce membranes having a constant fluidity at different temperatures of growth.
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PMID:Thermal regulation of the fatty acid composition of lipopolysaccharides and phospholipids of Proteus mirabilis. 20 38

The determination of the lipid A content of bacterial lipopolysaccharide by using a dim mutant of the luminous bacterium Beneckea harveyi is described. The luminous bacteria emitted light upon the addition of an acid hydrolysate of lipopolysaccharide which contained myristic acid, thus making it possible to detect as little as 1 ng of lipopolysaccharide. By converting the 3-OH-myristic acid to myristic acid, it was possible to further increase the detection sensitivity and to establish a basis for a specific and highly sensitive bioassay for the detection of lipopolysaccharide.
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PMID:Determination of lipopolysaccharide by a bioluminescence technique. 37 33

A cellular phenol-water extract of Acetobacter xylinum NRC 17007 was fractionated on Sepharose 4 B. The fraction eluting with the void volume consisted to about 95% of glycogen-like material. The lipopolysaccharide fraction was of lower molecular weight and had the following composition (%, w/w): Mannose, 42; glucose, 7; galactose, 3.8; heptose, 2; 2-keto-3-deoxy-octonate, 1.2; glucosamine, 3.3; phosphate, 4.5; total fatty acids, 3.9. Among the fatty acids, 3-hydroxy-tetradecanoic acid was present, and 2-hydroxy-hexadecanoic acid predominated.
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PMID:Isolation of alpha-glucan and lipopolysaccharide fractions from Acetobacter xylinum. 60 42

Lipid A was isolated from lipopolysaccharide of Yersinia pseudotuberculosis S form (strain 341, subtype IB) using mild hydrolysis with acetic acid. The purified material (yield about 25%, molecular weight about 2900) contained D-glucosamine (11%), fatty acids (54%), protein concomitant (9.7%) and phosphorus (approximately 2%). Dodecanoic and 3-hydroxy-tetradecanoic acids in a molar ratio of 1 : 3.6 were detected as major fatty acid constituents. The hydroxyl groups of D-glucosamine were acylated with the residues of both fatty acids, while the amino groups were substituted with the residue of 3-hydroxy-tetradecanoic acid. Such a simple fatty acid composition is reminiscent of that found in lipid A in Y. pestis.
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PMID:Studies on lipid A from Yersinia pseudotuberculosis lipopolysaccharide. Isolation and general characterization. 69 14

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

Cells of the stable protoplast L-form of Proteus mirabilis contain 1.5 to 2 times more extractable lipid, mostly phospholipid, per dry weight than cells of the bacterial form. Under identical conditions of cultivation the qualitative and quantitiative composition of the phospholipid is very similar in both cell forms. The range of mole percentages of individual phospholipid species is 78-80 for phosphatidylethanolamine, 10-13 for phosphatidylglycerol, 3.9-5.5 for diphosphatidylglycerol and 1.0-2.1 for lysophospholipid. However, all phospholipid species in the L-form differ from those of the bacterial form by a lower content of long-chain fatty acids and a higher content of short-chain fatty acids. Growth of the L-form in the presence of growth-stimulating horse serum results in a change of phospholipid composition accompanied by the uptake of phospholipid and fatty acids from the serum into L-form phospholipid. L-form protoplasts synthesize the same two types of lipopolysaccharide, I and II, that were previously identified in the bacterial form of Proteus mirabilis. However, only small amounts of the more hydrophilic lipopolysaccharide II are present in the L-form. Lipopolysaccharides from both cell forms have virtually identical polysaccharide compositions but differ strikingly in the relative content of fatty acids in their lipid-A moieties. Molar ratios of tetradecanoic acid, hexadeconoic acid and 3-hydroxytetradecanoic acid are 5:1:6 in the bacterial form and 5:0:1:6 in the L-form grown in serum-free medium. The observated differences between the bacterial form and the protoplast L-form are interpreted as results of the adaptation of the L-form to life in the state lacking an envelope by formation of a physically more stable but still sufficiently fluid protoplast membrane. A rapid method based on fatty acid analysis for the simultaneous quantitative determination of phospholipid and lipopolysaccharide content of whole cells is reported.
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PMID:Phospholipid and lipopolysaccharide in Proteus mirabilis and its stable protoplast L-form. Difference in content and fatty acid composition. 78 31

The cell envelope of Neisseria gonorrhoeae, colony type 4, was studied. Outer membrane was isolated by lysozyme and ethylenediaminetetraacetic acid treatment of plasmolyzed cells according to Wolf-Watz et al. (1973). The degree of purity of the membrane preparations was checked by electron microscopy. The membrane fraction obtained had a density of 1.25 g/cm(3), was rich in phospholipase A and lysophospholipase, and contained only 10% of the total membrane activity of succinate dehydrogenase and d-lactate dehydrogenase. The outer membrane protein profile after sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed at least six major proteins. The predominating protein showed a molecular weight of 35,000. The lipopolysaccharide component was characterized by gas chromatography. The carbohydrates found were galactose, glucose, and glucosamine. d-Glycero-l-manno-heptose was present in very low amounts. Lipid A contained lauric acid, stearic acid, and beta-hydroxy-myristic acid. About 20% of the fatty acids in the outer membrane was derived from lipid A. The phospholipids were characterized as phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. There was no evidence for a lipoprotein anchored to the peptidoglycan. The peptidoglycan of N. gonorrhoeae was of the chemotype I. The cell envelope of N. gonorrhoeae was found to be highly permeable to gentian violet. Cell envelopes of one penicillin-resistant and two penicillin-sensitive strains were compared. Only moderate differences in fatty acid composition were found.
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PMID:Cell envelope of Neisseria gonorrhoeae: outer membrane and peptidoglycan composition of penicillin-sensitive and-resistant strains. 80 26

Cultures of eight non-pathogenic species of Neisseria grown in simple defined media released lipopolysaccharide (free lipopolysaccharide) by a process distinct from cellular autolysis. Analyses of the pure cellular and free lipopolysaccharides obtained from six species of Neisseria revealed that they were remarkably similar and were devoid of detectable O-antigen side chains. Three distinct types of core-oligosaccharides were demonstrated. Type I core-oligosaccharide was a branched structure of alpha-D-glucopyranosyl units (7 mol) terminated by a reducing end group of 3-deoxy-D-manno-octulosonic acid. Type II core-oligosaccharide contained D-glucose, 2-deoxy-2-amino-D-glucose, L-rhamnose, L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid, phosphate, and ethanolamine in a molar ratio of 3:2:1:1:1:1:1. Type III coreoligosaccharide was composed of D-glucose, L-glycero-D-manno-heptose, 3-deoxy-D-manno-octulosonic acid, and phosphate in a molar ratio of 3:3:1:1. Lipopolysaccharides of N. caviae and N. sicca contained type I core-oligosaccharides exclusively, while those of N. flava and N. perflava contained only type II core-oligosaccharide. Cellular lipopolysaccharide from N. cinerea contained core-oligosaccharides of types I and II in a ratio of 27:73, while the analogous preparation from N. flavescens contained core-oligosaccharide types II and III in a ratio of 21:4. Free lipopolysaccharides from these two organisms contained only one type of coreoligosaccharide. Lipid A components of all the lipopolysaccharide preparations were very similar being composed of about 25% by weight of dodecanoic acid, 3-hydroxy-dodecanoic acid, and 3-hydroxy-tetradecanoic acid.
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PMID:Cellular and free lipopolysaccharides of some species of Neisseria. 122 Aug 63

Naegleria fowleri, which produces a fatal meningoencephalitis in humans, is also able to produce a progressive and fatal disease in mice. The course of the disease in DUB/ICR mice is dependent upon the infecting dose of organisms, whether administered intraperitoneally (i.p.) or intravenously (i.v.). All of the mice receiving 10(7) trophozoites/mouse i.v. or 4.85 X 10(7) trophozoites/mouse i.p. were killed within 10 days. Escherichia coli O26:B6 lipopolysaccharide, administered at a dose of 1 mg/kg 24 h prior to N. fowleri, afforded some protection for several days after challenge, but by day 8 there was no difference in survival of untreated and endotoxin-treated mice. No significant protection was afforded by a complex of lipid A with concanavalin A (ConA) or bovine serum albumin (BSA) or by dimethylmyristamide-BSA, dimethylmyristamide, BSA, beta-hydroxymyristic acid-ConA, beta-hydroxymyristic acid, ConA, myristic acid-BSA, or myristic acid. Mice surviving primary i.v. or i.p. challenge doses of N. fowleri, 5 X 10(6) and 10(7) trophozoites/mouse, respectively, were highly resistant to rechallenge with an i.v. dose of organisms (5 X 10(6) Naegleria/mouse) that produced uniformly fatal disease in untreated control mice.
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PMID:Modification of resistance of mice to Naegleria fowleri infections. 127 Jan 45

The amounts of tissue factor (TF) expressed by brain microvascular endothelial cells (BMECs) from normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were compared after stimulating the cells with different doses of lipopolysaccharide (LPS), thrombin, phorbol myristic acid (PMA), Ca(2+)-ionophore (A23187), or tumor necrosis factor (TNF) and interleukin-1 (IL-1). Treatment of cultured BMECs from WKY and SHR with all of these factors dose-dependently increased their total amount of TF; no substantive differences in the levels of enhanced TF expression were observed between WKY and SHR BMECs. We conclude that stimulated endothelium from rats with hypertension, a major stroke risk factor, is not hyperresponsive with respect to TF expression when compared to normotensive controls.
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PMID:Comparison of stimulated tissue factor expression by brain microvascular endothelial cells from normotensive (WKY) and hypertensive (SHR) rats. 147 6


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