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

The extractable and bound lipids of a moderately halophilic gram-negative rod, strain No. 101 (wild type) grown in a medium containing 2 M NaC1, were examined. The extractable lipids were separated into at least 8 components by using thin-layer chromatography. The major phospholipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unidentified phosphoglycolipid in the whole cells, cell envelopes and outer membrane preparations, commonly. Judging from mild alkaline hydrolysis and exzymatic treatment with phospholipase A2, C and D, the unidentified phosphoglycolipid possessing Pi, glycerol, fatty acids and glucose in a molar ratio of 1 : 2 : 2 : 1, appeared likely to be a glucosyl derivative of phosphatidylglycerol. No glucuronic acid containing lipid was detected. The exractable lipid composition varied greatly with the concentrations of NaC1 in the medium and the stages of bacterial growth. The most characteristic phosphoglycolipid in this organism increased up to 25% of the total phospholipids with the addition of 1% glucose in the medium. The major fatty acids of the extractable lipids were C16:0, C16:1, C18:0, C18:1 and cyclopropanoic C17 and C19 acids and these compositions were very similar for each phospholipid. The cyclopropanoic fatty acids predominated as growth proceeded. The fatty acids of the bound lipids comprised a high concentration of 3-hydroxydodecanoic acid. The esterified fatty acids of the lipopolysaccharide molecule seemed to contain a wide variety of hydroxy and non-hydroxy shorter chain fatty acids, while the amide-linked fatty acids consisted almost entirely of 3-hydroxydodecanoic acid.
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PMID:Lipids and fatty acids of a moderately halophilic bacterium, No. 101. 125 64

A chemical analysis was performed of lipid A, isolated by acid hydrolysis of the lipopolysaccharide from the S and R forms of Shigella dysenteriae serovar 1. Differences in the moiety of both lipids and sugars were compared. The lipid portion consisted of a homologous series of fatty acids ranging from C12:0 to C18:0 (predominant homologues, C12:0, C14:0 and C16:0) and the homologous series of 3-hydroxy acids ranging from C12:0 to C16:0 (predominant homologue, 3-OH-C14:0). The major sugar portion consisted of D-glucosamine. The toxicity of lipid A in mice (LD50) ranged between 300-400 micrograms/mouse, and values from the Limulus amebocyte lysate assay were recorded as titres of 10(-5) to 10(-6) mg/ml.
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PMID:Composition of lipid A in the S and R forms of Shigella dysenteriae serovar 1. 130 86

Several models for the transport of proteins across membranes predict a role for lipids. If these models are correct, then alterations in lipid metabolism may affect protein export and vice versa. We are investigating this possibility by studying Escherichia coli K-12 mutants with defects in protein export or phospholipid metabolism. A temperature-sensitive secA mutant, which is defective in protein export at 42 degrees C, exhibited severe pleiotropic effects on membrane biogenesis. Incubation of this strain at 42 degrees C resulted in the appearance of intracytoplasmic membranes, in alterations in lipopolysaccharide structure and in decreased cardiolipin and C18:1 fatty acid content. On the other hand, a pgsA mutant which is defective in the synthesis of acidic phospholipids, exhibited a protein export defect when studied in vivo or in vitro. These results are in agreement with a postulated role of membrane lipids in protein export.
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PMID:Involvement of membrane lipids in protein export in Escherichia coli. 269 62

A new hydroxylated, very long-chain fatty acid has been isolated and characterized from the lipopolysaccharide (LPS) of Rhizobium trifolii ANU 843. The lipid A of the organism was degraded by mild alkali and borohydride and the products methylated, peracetylated, and fractionated on a C18 reverse-phase column. The major lipid fraction was reduced with lithium triethylborohydride, methylated, peracetylated, and subjected to thin layer chromatography. The methylated peracetylated acid and the reduced diacetylated diol (1,27-dihydroxyoctacosane diacetate) were isolated and characterized by mass spectrometry and 1H NMR spectroscopy using homonuclear decoupling. The identity and linkage of the new fatty acid in the lipopolysaccharide was confirmed by 1H NMR spectroscopy of purified lipid A fractions and similar NMR studies of lipid A after acylation by phenylisocyanate. In the native LPS, the 27-hydroxy C-28 fatty acid is acylated at the 27-hydroxy position by other 3-hydroxy fatty acids. About 50% of the total fatty acid content of the LPS of R. trifolii ANU 843 is 27-hydroxyoctacosanoic acid. This oxyacyloxy structure involving 27-hydroxyoctacosanoic appears to be the major structural feature of the lipid A of this organism.
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PMID:27-Hydroxyoctacosanoic acid is a major structural fatty acyl component of the lipopolysaccharide of Rhizobium trifolii ANU 843. 272 34

Two new, unusual lipid A components have been isolated and characterized from the free lipid A of Rhizobium trifolii ANU843. 2-Amino-2-deoxy-2-N-(27-hydroxyoctacosanoyl)-3-O-(3-hydroxy- tetradecanoyl)-gluco-hexuronic acid and its de-O-acylation product were purified from the chloroform/methanol extract of a mild acid hydrolysate of the lipopolysaccharide by chromatography on C18 reverse-phase columns and layers. The compositions of the two compounds were determined by releasing the acyl components by exhaustive acid-catalyzed methanolysis and identifying them as their methyl esters by gas chromatography and gas chromatography/mass spectrometry. The sugar component was identified by converting it to the alditol acetate derivative of glucosamine in a two-step reduction and identifying it as such by gas chromatography/mass spectrometry. The linkages of the fatty acyl components to the sugar residue and the configuration of the sugar component was confirmed by 1H and 13C NMR spectroscopy. The complete structures of the two compounds were further confirmed by fast atom bombardment mass spectrometry. It is still unsure whether the de-O-acylated derivative was formed from the di-acyl compound by de-O-acylation during acid hydrolysis. These structures represent the first report of 2-amino-2-deoxy-gluco-hexuronic acid in the free lipid A of a Gram-negative bacterium and confirms our earlier contention (Hollingsworth, R.I., and Carlson, R. W. (1989) J. Biol. Chem. 264, 9000-9303) of the involvement of 27-hydroxyoctacosanoic acid in the structure of the lipopolysaccharide of Rhizobium trifolii ANU843.
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PMID:Isolation and characterization of the unusual lipopolysaccharide component, 2-amino-2-deoxy-2-N-(27-hydroxyoctacosanoyl)-3-O-(3-hydroxy- tetradecanoyl)-gluco-hexuronic acid, and its de-O-acylation product from the free lipid A of Rhizobium trifolii ANU843. 276 55

The nature of the protective antigen in one of the sixteen monovalent extracts (viz., extract-6) contributing to the pseudomonas polyvalent extract vaccine (PEV) was studied in a mouse challenge assay. Selective removal, by filtration through Sep-Pak C18 cartridges, of two major protein antigens with molecular weights of 16,200 and 21,000 had no effect on the protection afforded by extract-6. When analyzed on the basis of 2-keto-3-deoxyoctonate, lipopolysaccharide (LPS) purified by hot phenol extraction (LPS-A) from Pseudomonas aeruginosa (International Antigenic Typing System serotype 6) could account in full for the protective capacity of extract-6. Comparative analysis of LPS heterogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by silver staining indicated that both extract-6 and LPS-A possessed similar spectra of smooth LPS molecules, containing between 10 and approximately equal to 50 O-antigen repeating units. Differences in the profiles of heterogeneity displayed by LPS in LPS-A and extract-6 were restricted to molecular species with short O-antigen chains. Subfractionation of LPS molecules on the basis of number of O-antigen repeating units was achieved by gel filtration in the presence of deoxycholate. Protection experiments performed on the subfractionated species of LPS-A revealed a relationship between O-antigen chain length and protective capacity; molecules with over 18 O-antigen repeating units being 50 to 100 times more protective than those with zero-two repeating units. The results indicate that most of the protection afforded by LPS-A and extract-6 can be accounted for by LPS molecules possessing extended (10 or more) O-antigen repeating units.
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PMID:Smooth lipopolysaccharide is the major protective antigen for mice in the surface extract from IATS serotype 6 contributing to the polyvalent Pseudomonas aeruginosa vaccine PEV. 308 62

The aqueous layer was isolated from Leptospira interrogans serovar canicola strain Moulton by the hot phenol-water method. After ultracentrifugation, the precipitate was designated as lipopolysaccharide-like substance (LLS) fraction and the chemical composition was compared with that of bacterial LPS. The LLS fraction consists of 35.2% carbohydrate, 3.8% amino sugar, 36.4% lipid, 15.2% protein, and 0.3% phosphorus. Neutral sugars were detected as rhamnose, arabinose, xylose, 4-O-methylmannose, mannose, galactose, and a small amount of erythrose, fucose and glucose by gas-liquid chromatography (GLC), but 2-keto-3-deoxyoctonic acid was not detected in the LLS by thiobarbituric acid test and high voltage paper electrophoresis. Fatty acids detected by GLC were decanoic acid (C10: 0), dodecanoic acid (C12: 0), dodecenoic acid (C12: 1), tridecenoic acid (C13: 1), tetradecanoic acid (C14: 0), hexadecanoic acid (C16: 0), hexadecenoic acid (C16: 1), and octadecenoic acid (C18: 1). With SDS-polyacrylamide gel electrophoresis, bacterial LPS showed many orderly bands, while the banding pattern of the leptospiral LLS was very simple. These findings demonstrate that the physicochemical properties and chemical composition of LLS fraction from Leptospira are different from those of LPS extracted from gram-negative bacteria such as Enterobacteriaceae, and suggesting that Leptospira has no typical LPS.
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PMID:Chemical properties of lipopolysaccharide-like substance (LLS) extracted from Leptospira interrogans serovar canicola strain Moulton. 368 16

The phospholipids and lipopolysaccharide of Aeromonas hydrophila were characterized. Phosphatidylethanolamine and phosphatidylglycerol were the major phospholipid components. The outer membrane contained more phosphatidylethanolamine and less phosphatidylglycerol than the inner membrane, and the phospholipids of the outer membrane contained a higher proportion of saturated fatty acids. Only four fatty acids (C14:0, C16:0, C16:1, and C18:1) were found in the phospholipids. The lipopolysaccharide of A. hydrophila did not contain the eight-carbon sugar 3-deoxyoctulosonic acid nor did it contain C16:0, both of which are typical constituents of the lipopolysaccharide of many other species.
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PMID:Phospholipids and lipopolysaccharide of Aeromonas hydrophila. 396 30

In Escherichia coli K-12 the envA gene was previously shown to mediate chain formation and a decreased tolerance to several antibacterial agents. Phenethyl alcohol at low concentrations has now been found to increase the tolerance to actinomycin D, ampicillin, rifampin, and gentian violet in strains containing envA. The increased tolerance to gentian violet was correlated to a decreased uptake of the dye. A phenotype suppression of chain formation and colony morphology in envA mutants was also obtained. Except for an increase in palmitic acid, chemical analysis revealed no differences between an envA and its wild-type strain in the lipopolysaccharide part of the envelope. However, a decrease in the amount of phosphatidylglycerol and a C18: 1 fatty acid was observed in the extractable lipids of a strain containing envA. Growth in the presence of phenethyl alcohol reversed the changes in fatty acid and the phospholipid composition. Phenethyl alcohol was found to cause an immediate but transient inhibition of ribonucleic acid synthesis. It is suggested that this inhibition affects the penetrability barrier of the outer cell envelope layers in strains containing envA.
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PMID:Phenethyl alcohol as a suppressor of the envA phenotype associated with the envA gene in Escherichia coli K-12. 494 68

Sucrose density gradient centrifugation of cell envelopes of chemotrophically grown cells of Rhodopseudomonas capsulata St. Louis (= ATCC 23782) resulted in the separation of a cytoplasmic membrane from a cell wall fraction (buoyant densities, 1.139 and 1.215 g/cm3, respectively). The cell wall fractions (untreated or Triton extracted) contained peptidoglycan- and lipopolysaccharide-specific components. Their neutral sugar content, mainly rhamnose and galactose, was high (250 and 100 micrograms/mg [dry weight] of material) due to a non-lipopolysaccharide polymer. The fatty acid content was low (less than or equal to 60 micrograms/mg [dry weight] of material), and half of it was contributed by lipopolysaccharide (3-OH-C10:0, C12:1, and 3-oxo-C14:0). The predominant other fatty acid was C18:1. An outer membrane fraction, obtained by lysozyme treatment of the Triton-extracted cell wall, showed essentially the same chemical composition except for almost complete removal of peptidoglycan. Saline extraction (0.9% NaCl, 37 degrees C, 2 h) removed a lipopolysaccharide-protein(-phospholipid?) complex from whole cells of R. capsulata St. Louis. The polypeptide patterns of the cell wall and outer membrane as revealed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis comprised 20 to 25 different polypeptides (most of them very faint) and were dominated by a single, heat-modifiable major protein (Mr 69,000 after solubilization below 60 degrees C; Mr 33,000 at temperatures above 70 degrees C).
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PMID:Characterization of the cell wall and outer membrane of Rhodopseudomonas capsulata. 673 79


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