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

Flagellar proteins controlling motility and chemotaxis in Escherichia coli were selectively labeled in vivo with [35S]methionine. This distribution of these proteins in subcellular fractions was examined by sodium dodecyl sulfatepolyacrylamide gel electrophoresis and autoradiography. The motA, motB, cheM, and cheD gene products were found to be confined exclusively to the inner cytoplasmic membrane fraction, whereas the cheY, cheW, and cheA (66,000 daltons) polypeptides appeared only in the soluble cytoplasmic fraction. The cheB, cheX, cheZ, and cheA (76,000 daltons) proteins, however, were distributed in both the cytoplasm and the inner membrane fractions. The hag gene product (flagellin) was the only flagellar protein examined that copurified with the outer lipopolysaccharide membrane. Differences in the intracellular locations of the che and mot gene prodcuts presumably reflect the functional attributes of these components.
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PMID:Localization of proteins controlling motility and chemotaxis in Escherichia coli. 33 49

The inhibitory action of decanoic acid on both Escherichia coli K-12/154 (normal lipopolysaccharide) and E. coli RC59 (defective lipopolysaccharide) was studied. A correlation was found between the doubling time of E. coli 154 growing in different media and the lethal effect of 0.4% decanoic acid on this bacterium. Decanoic acid (0.4%) exerted a lytic action on glucose-starved and NaN3-inhibited cells of E. coli 154 and RC59. Exponentially growing cultures of both strains were not affected by the addition of 0.4% methyldecanoate, but cells of E. coli RC59 reaching the stationary phase were attacked by that compound. A bactericidal action of 0.4% methyldecanoate on exponential E. coli 154 and RC59 was observed when sodium azide was also present in the media. Concentrations lower than 0.01% methyldecanoate had a lytic effect on spheroplasts from E. coli 154 and RC59. These results indicate that the inhibitory action of a non-metabolizable fatty acid on E. coli depends on the cellular metabolic activity and the outer membrane integrity.
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PMID:Inhibitory action of a non-metabolizable fatty acid on the growth of Escherichia coli: role of metabolism and outer membrane integrity. 33 6

The molecular weight of the protein moiety of a phospholipoprotein complex isolated from Pseudomonas facilis has been examined with a variety of sodium dodecylsulfate-polyacrylamide gel electrophoretic systems. A molecular weight of 35 000 was determined for the protein in all analyses. A 35 000-dalton protein was present in the EDTA extract of P. facilis and in the cytoplasmic and outer membrane fractions, but not in the lipopolysaccharide and peptidoglycan. Prior inoculation of mice with the phospholipoprotein complex led to a 7.5- to 15-fold increase in the LD50 when mice were subsequently inoculated with Salmonella typhimurium; this pathogen has a cell-surface protein which cross-reacts immunologically with antibody to the P. facilis phospholipoprotein complex.
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PMID:Properties of the cell envelope and a cell-envelope protein of Pseudomonas facilis. 33 20

Outer membrane proteins extracted from isolated cell walls of Proteus mirabilis were able to combine the cell wall phospholipids in a model membrane system. The presence of outer membrane proteins in vesicular model membranes mediated the release of previously entrapped [14C]sucrose while [3H]inulin was retained. Incorporation of lipopolysaccharide from the same cell walls was not required for the formation of such selectively permeable membranes. Three major outer membrane proteins of apparent molecular weights 39000, 36000 and 17000 were isolated using acetic acid and sodium deoxycholate solution as solvents and avoiding the strongly denaturing sodium dodecyl sulfate. The isolated proteins were assayed for their ability to form hydrophilic pores in reconstituted membranes. The trypsin-sensitive 39000-Mr protein and the peptidoglycan-associated 36000-Mr protein were equally effective in this function whereas the 17000-Mr protein mediated little penetration of low molecular weight solute. The 39000-Mr and 36000-Mr proteins also protected reconstituted membrane vesicles from disruption by detergent while 17000-Mr protein was ineffective in this regard.
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PMID:Reconstitution of model membranes from phospholipid and outer membrane proteins of Proteus mirabilis. Role of proteins in the formation of hydrophilic pores and protection of membranes against detergents. 33 2

Isolated membrane fractions of Escherichia coli K-12 yielded complex immunoprecipitate patterns when Triton X-100 and sodium dodecyl sulfate extracts were examined by crossed immunoelectrophoresis with antienvelope immunoglobulins. Twelve of the 46 antigens in the immunoprecipitate patterns of inner (plasma) membranes were identified by zymograms and/or by the use of specific antisera. The following enzyme activities were detected in immunoprecipitates: 6-phosphogluconate dehydrogenase (EC 1.1.1.43); adenosine triphosphatase (EC 3.6.1.3); glutamate dehydrogenase (EC 1.4.1.4), two separate components; malate dehydrogenase (EC 1.1.1.37); dihydroorotate dehydrogenase (EC 1.3.3.1); succinate dehydrogenase (EC 1.3.99.1); lactate dehydrogeanse (EC 1.1.1.27); reduced nicotinamide adenine dinucleotide dehydrogenase (EC 1.6.99.3); protease (EC 3.4.21.1); and glycerol 3-phosphate dehydrogenase (EC 1.1.99.5). The corresponding immunoprecipitate pattern for isolated outer membranes consisted of at least 25 discrete antigens and differed strikingly from that obtained with inner membranes. Two major immunogens were identified as lipopolysaccharide and Braun lipoprotein. A protease-active immunoprecipitate was also detected in this fraction, but attempts to identify the Rosenbusch matrix protein in the crossed immunoelectrophoretic profile were unsuccessful.
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PMID:Immunochemical analysis of inner and outer membranes of Escherichia coli by crossed immunoelectrophoresis. 33 83

Antibodies directed against the protein constituents of the outer envelope membrane of Escherichia coli O26 K60 were demonstrated in antisera elicited in rabbits against three different preparations of the bacterium. Outer membraned solubilized by sodium dodecyl sulphate were applied to the antisera in an interfacial precipitin test, followed by polyacrylamide gel electrophoretic analysis of the resulting immunecomplexes. Protein profiles showed a complete outer membrane protein pattern, indicating the antigenic character of these proteins. Antisera containing antibodies against outer membrane proteins and free of reactive antibodies against lipopolysaccharide showed relatively low agglutinating activities against the bacteria. The antibodies against the protein constituents of the outer membrane belong mainly to the 7S class immunoglobulins, as indicated by 2-mercaptoethanol treatment of the antisera.
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PMID:Antibodies against outer membrane proteins in rabbit antisera prepared against Escherichia coli O26 K60. 34 33

Heat-stable enterotoxin (ST) produced by porcine strains of enterotoxigenic (ENT+) Escherichia coli has been purified to apparent homogeneity by sequential ultrafiltration, acetone fractionation, preparative gel electrophoresis, diethylaminoethyl Bio-Gel A ion-exchange chromatography, and Bio-Gel P-10 gel filtration. The enterotoxin, purified more than 1,500-fold, exhibited a molecular weight of 4,400, as determined by both sodium dodecyl sulfate-gel electrophoresis and gel filtration. A molecular weight of 5,100, representing 47 residues, was calculated from amino acid analysis data. The amino acid content was distinctive, with an unusually high proportion of cystines and few hydrophobic amino acids. A single amino-terminal residue, glycine, was observed. Purified ST was stable to heating (100 degrees C, 30 min) and did not lose biological activity after treatment with Pronase, trypsin, proteinase K, deoxyribonuclease, ribonuclease, and phospholipase C. Periodic acid oxidation and several organic solvents (acetone, phenol, chloroform, and methanol) had no effect on the biological activity of ST. Further, purified ST was stable to acid treatment at pH 1.0 but lost biological activity at pH values greater than 9.0. Neither lipopolysaccharide nor lipid contamination was evident in purified preparations. A characteristic absorption spectrum was observed during the course of the purification, which shifted from a maximum at 260 nm in crude preparations to 270 nm for the purified toxin. Antiserum obtained from rabbits immunized with ST or ST coupled to bovine serum albumin neutralized the action of the enterotoxin in suckling mice; however, passive hemagglutination and hemolysis titer assays suggested that ST is a poor antigen.
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PMID:Purification and chemical characterization of the heat-stable enterotoxin produced by porcine strains of enterotoxigenic Escherichia coli. 34 81

Various mutants (oxas) were isolated from Serratia marcescens SM-6 by selecting for hypersensitivity towards oxacillin. All mutants found are highly pleiotropic and able to yield spontaneous revertants which behave like the wild-type. Mutant W 1421 mostly studied shows the following phenotypic properties not found in the wild-type: (1) The growth is hypersensitive to various antibiotics, detergents and dyes which differ remarkably in their chemical structure and antibacterial action-mechanism, (2) the cells can be easily solubilized by 0;05% Sodium-dodecyl-sulfate, (3) the cells allow the adsorption of the rough-mutant specific Salmonella phage 6SR; (4) strong cellular binding of crystal violet, (5) agglutination of the cells in 0.3% auramin solution and (6) reduced formation of red pigment. Strain W 1421 is assumed to be a lipopolysaccharide-defective mutant. The outer membrane of mutant W 1421 analyzed by Sodium-dodecylsulfate-polyacrylamide gel electrophoresis possesses a single protein less than that of the wild-type. Mutant W 1421 is further characterized by its low exolipase activity; exoprotease and exonuclease activities are as in the wild-type. This specific exoenzyme deficiency can be overcome either by backmutation to oxacillin-resistance or by growing mutant W 1421 in a medium supplemented with certain non-metabolizable polysaccharides, e.g. glycogen or pectin B. Both polysaccharides increase the exolipase activity of the wild-type too.
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PMID:Pleiotropic consequences of mutations towards antibiotic-hypersensitivity in Serratia marcescens. 34 45

The natural occurrence of cations Fe, Zn, Mg, and Ca in the lipopolysaccharide (LPS) of both the S and R forms of Shigella dysenteriae 1 was studied. LPS preparations were obtained either by phenol-water extraction (according to the method of Westphal et al., Z. Naturforsch. 7b:148-155, 1952) or by extraction of cells with hypertonic sodium chloride-sodium citrate (according to the method of Raynaud and Digeon, C. R. Acad. Sci. (Paris) 229:564-566, 1949), with subsequent chromatographic purification on Sephadex G200 and Sepharose 4B columns. The cation in highest concentration in the Westphal extract was Mg(2+) (as much as 30 mug/mg), and the lowest one was Fe (ca. 0.10 mug/mg). In LPS of the Raynaud type, the cation in highest concentration was Ca(2+) (as much as 13 mug/mg), and the lowest one was Fe (ca. 0.10 mug/mg). The effects of increasing and decreasing the concentrations of cations (Fe, Zn, Mg, Ca) upon the biological activity of the endotoxins was evaluated by using toxicity in mice and the Limulus test. It appeared that increased concentrations of Fe (chiefly of Fe(3+)) decreased the toxicity of the R form of LPS, whereas Mg(2+) decreased the toxicity of the S form. After prolonged dialysis of LPS preparations against deionized water, there was no consistent relationship between toxicity as determined in white mice and with the Limulus test.
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PMID:Effects of certain cations (Fe, Zn, Mg, and Ca) on bacterial endotoxins. 35 92

An ordered hexagonal lattice structure with a lattice constant of about 7 nm was reconstituted on the entire surface of the lipoprotein-bearing peptidoglycan from outer membrane protein O-8 and lipopolysaccharide. The lattice structure resembled that observed in the cell envelope which had been treated with sodium dodecyl sulfate (Steven et al., J. Cell Biol. 72:292-301, 1977). The omission of either O-8 or lipopolysaccharide resulted in the failure of formation of the lattice structure. No ordered lattice was formed on the peptidoglycan lacking the bound form of the lipoprotein. In the absence of the lipoprotein-bearing peptidoglycan, O-8 and lipopolysaccharide assembled into vesicles with an ordered hexagonal lattice, the lattice constant of which was also about 7 nm. A preliminary experiment indicated that protein O-9 gave the same result as did O-8. These results strongly indicate that O-8 and/or O-9 and lipopolysaccharide provide the ordered framework of the outer membrane and that the bound form of the lipoprotein plays a role in the holding of the framework on the peptidoglycan layer.
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PMID:Reconstitution of an ordered structure from major outer membrane constituents and the lipoprotein-bearing peptidoglycan sacculus of Escherichia coli. 35 12


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