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

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

ZnCl2 over a very narrow concentration range was found to be mitogenic for hamster lymph node cells but not for thymocytes or splenocytes. Maximal leucine, [3H]uridine, and [3H]thymidine incorporation. Addition of 10 micron ZnCl2 was found to greatly enhance the stimulation observed with the B-lymphocyte mitogen lipopolysaccharide but not with dextran sulfate or the T-lymphocyte mitogen lipopolysaccharide but not with dextran sulfate or the T-lymphocyte mitogen concanavalin A. Although not mitogenic for splenocytes, 10 to 25 micron ZnCl2 slightly enhanced lipopolysaccharide stimulation but not concanavalin A or dextran sulfate stimulation. The effect of ZnCl2 on lipopolysaccharide stimulation was also confirmed with outbred Hartley guinea pig splenocytes and lymph node cells. Zinc chloride (50 micron) was mitogenic for both of these tissues; the response to lipopolysaccharide was enhanced by addition of 50 micron ZnCl2, but the concanavalin A response was unaffected. The possibility that the zinc effect is mediated by proteolytic mechanisms is discussed.
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PMID:Effect of zinc chloride on hamster lymphoid cells: mitogenicity and differential enhancement of lipopolysaccharide stimulation of lymphocytes. 34 10

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

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

The effect of treatment with the methanol extraction residue (MER) mycobacterial fraction on the immunological responsiveness of BALB/c mice to the T-independent antigens pneumococcal polysaccharide type III (SIIII) and trinitrophenyl-lipopolysaccharide conjugate (TNP-LPS) was ascertained. Pretreatment with MER prevented the establishment of immunological paralysis by threshold doses (10 or 15 microgram) of SIII and by a paralyzing dose of 100 microgram TNP-LPS. The induction of immunological paralysis by SIII was unaffected by treatment with the bacterial adjuvant Corynebacterium parvum and with the B cell mitogens PPD, LPS (Escherichia coli lipopolysaccharide), and dextran sulfate.
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PMID:Effect of the MER tubercle bacillus fraction on the responsiveness of mice to T-independent antigens. 37 26

Human fetal cells from 10 prematures and newborn infants (28--38 weeks of gestational age) and isolated or non-isolated fetal cells circulating in the blood of 9 primigravidae were studied in their ability to respond to phytohemagglutinin, pokeweed, dextran sulfate and lipopolysaccharide. An age-dependent responsiveness of fetal cells obtained from the prematures to all mitogens tested was detected as well as a clear graduation of mitogenic capacity with phytohemagglutinin to produce the highest stimulation. Though a moderate mitogenic response to lipopolysaccharide and dextran sulfate was noted in the blood cultures of the infants, LPS and in part DS transformation of fetal cells obtained from maternal blood appeared to be reduced or absent. A selective stimulation of fetal cells occurring in the circulation of primiparae sufficient for prenatal diagnosis could not be achieved with the mitogens tested. The findings suggest that fetal cells crossing to the mother are different from normal fetal lymphocytes. The present study was performed to elucidate in as quantitative a manner as possible the responses of human fetal cells to different T- and B-cell mitogens. Cells were obtained from various sources for comparing the mitogenic responses of isolated and non-isolated fetal cells. Our results demonstrate that mitogenic responses depend on the gestational age of the fetal cells, the source of the cells and on experimental conditions.
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PMID:Human fetal cells. I. Mitogenic responses. 37 Nov 70

The antiphagocytic antigen (antigen [a]) comprising the microcapsule of a strain of Campylobacter fetus subsp. intestinalis has been purified from culture supernatants by ammonium sulfate fractionation and free-flow electrophoresis. Antigen [a] is a glycoprotein containing about 4% carbohydrate consisting of hexose, pentose, and methylpentose. The composition of the protein was typical of bacterial extramural structural proteins in its low content of basic, aromatic, and sulfur-containing amino acids. The protein had a high content of aspartic acid, threonine, glycine, and alanine. Antigen [a] had an Rf of 0.33 on polyacrylamide gel electrophoresis and a molecular weight calculated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 98,000. In contrast to its free form in culture supernatants, antigen [a] in vesicles derived from sheared cells appeared to exist in a complex with lipopolysaccharide. This complex could be dissociated by ethylenediaminetetraacetic acid or by ethylenediaminetetraacetic acid plus Triton X-100. A mutant strain that lacked a microcapsule, when incubated with soluble antigen [a] in a calcium medium, became agglutinable by monospecific [a] antiserum and showed an additional structural layer similar in appearance to the microcapsule on its cell wall. Points of similarity are emphasized between antigen [a] of C. fetus and the outer structural protein of the taxonomically related Spirillum serpens.
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PMID:Microcapsule of Campylobacter fetus: chemical and physical characterization. 73 Mar 87

Salmonella typhimurium outer membrane protein complexes can be reconstituted with lipopolysaccharide and phospholipids into membrane vesicles. These vesicles are permeable to a variety of low molecular weight compounds, but not to oligo- and polysaccharides of molecular weight higher than 700. A protein complex participating in selective membrane permeability can be isolated by gel filtration in the presence of sodium dodecyl sulfate. The active fractions contain three major protein species. The Braun lipoprotein is not associated with this subset of outer membrane proteins.
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PMID:Outer membrane of Salmonella. Isolation of protein complex that produces transmembrane channels. 77 34


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