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PubMed1974

Immunological analysis of glycolipids and lipopolysaccharides derived from various mycoplasmas.

The lipids and lipopolysaccharides of five mycoplasmas were examined for complement-fixing activity to antimembrane rabbit sera. Total glycolipid fractions and the aqueous phenol fractions (lipopolysaccharides) from the membranes of Acholeplasma laidlawii, A. modicum, A. axanthum, and Mycoplasma neurolyticum exhibited significant antigenic activity. The glycolipids and phosphoglycolipids from Thermoplasma acidophilum were either anticomplementary or did not react due to their extreme hydrophobic nature. High activity was found using the lipopolysaccharide of T. acidophilum. The pure glycolipids and phosphoglycolipids of the Acholeplasma and Mycoplasma species also exhibited significant complement-fixing activity. Acylation of the sugar residues of these lipids reduced or negated complement-fixing activity. Double cross-reactions between the glycolipids of A. laidlawii and A. modicum appeared to be due to mono- and diglucosyl diglycerides of identical structure. Specificity of glycolipid structure was noted by the absence of cross-reactions between A. laidlawii and M. neurolyticum, the glycolipids of which differ only in the nature of the glucose linkages. The existence of lipopolysaccharides in the membranes of mycoplasmas and their complement-fixing activity in the presence of antimembrane sera suggest their possible importance as specific antigenic determinants.

Animals↗

PubMed1976

Fate of 51Cr-labeled lipopolysaccharide in tissue culture cells and livers of normal mice.

Livers of normal mice trapped over 80% of intravenously injected 51Cr-labeled lipopolysaccharide after 1 h. Liver fractionation studies showed that nearly 45% of the labeled endotoxin was associated with cell nuclei, 20% with the mitochondrial-lysosomal fraction, and approximately 30% with the cell sap. Analysis of the distribution of 51Cr-labeled lipopolysaccharide among parenchymal and Kupffer cells showed that over 75% of the in vivo-trapped counts were parenchymal cell associated. Cell populations were approximately 65% parenchymal cells and 35% nonparenchymal cells. Further, six non-reticuloendothelial system tissue culture cell lines were tested for their ability to internalize labeled lipopolysaccharide. In all cells studied, 1 to 4% of the labeled lipopolysaccharide was taken up after 3 h, with greater than 80% of the counts localized in the nuclear fraction. The data show that non-reticuloendothelial system cells can sequester endotoxin both in vivo and in vitro and suggest that parenchymal cells as well as Kupffer cells remove circulating endotoxin from the blood.

Animals↗

PubMed1977

Mild alkaline hydrolysis of lipopolysaccharide endotoxin enhances its mitogencity for murine B cells.

Mild alkaline hydrolysis was found to enhance the mitogenicity of lipopolysaccharide endotoxin for murine B lymphocytes. Alkaline treated lipopolysaccharide also retained its property as a polyclonal activator. Whereas this treatment reduced the lethality of endotoxin for mice, its toxicity for lymphocytes cultured in the absence of fetal calf serum was increased. Lipid analysis indicated that there were no significant changes in the fatty acids of lipid A, but particle size was significantly reduced and the material was more homogeneous and soluble than untreated lipopolysaccharide. The relationship of these effect on the structure of lipopolysaccharide endotoxin to the mechanism of B-lymphocyte activation is discussed.

Animals↗

PubMed1979

Transfer by bone marrow cells of increased natural resistance to Klebsiella pneumoniae induced by lipopolysaccharide in genetically deficient C3H/He mice.

In a previous study we demonstrated that lipopolysaccharide failed to elicit nonspecific resistance in C3H/He lipopolysaccharide low-responder mice against Klebsiella infection in contrast to its activity in a closely related histocompatible high-responder subline, C3HeB/Fe. Complete restoration of lipopolysaccharide-induced protection against 10(5) Klebsiella was obtained in the present study by transferring bone marrow from high-responder mice to the highly deficient C3H/He mice. The ability of C3H/He mice to clear and destroy bacteria in 5 h was also transferred by C3HeB/Fe marrow cells. In contrast, when high-responder C3HeB/Fe mice were reconstituted with low-responder bone marrow, the clearance and destruction of K. pneumoniae were similar to what is observed in the high-responder strain, but survival was only temporary. Collectively, our data show that the failure of C3H/He mice to respond to lipopolysaccharide with nonspecific immunity is due to a defect in two types of bone-marrow-derived cells--radioresistant and radiosensitive.

Animals↗

PubMed1981

Increased resistance and depressed delayed-type hypersensitivity to Listeria monocytogenes induced by pretreatment with lipopolysaccharide.

Intravenous injection of a small dose of lipopolysaccharide 24 h before infection with Listeria monocytogenes enhanced the resistance of mice to this organism. This protective effect of lipopolysaccharide related to the ability of nonimmune macrophages to inhibit bacterial proliferation in livers and spleens. Surprisingly, lipopolysaccharide-treated mice exhibited inferior acquired immunity, as measured by adoptive transfer of immunity to normal mice, delayed-type hypersensitivity to Listeria antigens, and uptake of tritiated thymidine by lymphocytes in the spleen. These results support the view that lipopolysaccharide stimulates a highly effective anti-Listeria immunity via the macrophage component, despite interference with the lymphocyte component.

Animals↗

PubMed1983

Effect of lipopolysaccharide mutations on the pathogenesis of experimental Salmonella gastroenteritis.

Lipopolysaccharide mutants of Salmonella typhimurium provoked diminished amounts of fluid in rabbit ileal loops as compared with the response to the wild type. The responses elicited by these mutants ranged from 0 to 60% of that caused by the parent strain. Two completely rough mutants and one leaky rough mutant were chosen for further study. Purified lipopolysaccharide from the parent and the mutant strains failed to stimulate fluid exsorption in ileal loop experiments. Histological studies revealed that the three lipopolysaccharide mutants were less invasive than wild type and were less able to generate an inflammatory reaction in the rabbit ileum. A Salmonella enterotoxin was present in culture filtrates from one rough mutant and the wild type; however, the rough mutant appeared to produce less toxin. Enterotoxic activity was absent in culture filtrates from the two other rough mutants. These results suggest that reductions in both invasiveness and the ability to produce Salmonella enterotoxin decreased the ability of these mutants to provoke fluid exsorption. Also, the results indicate that lipopolysaccharide mutations can have a profound effect on the enteropathogenic properties of S. typhimurium.

Adhesiveness↗

PubMed1984

Monoclonal antibodies specific for Escherichia coli J5 lipopolysaccharide: cross-reaction with other gram-negative bacterial species.

Four monoclonal antibodies against Escherichia coli J5 were studied. Each of these monoclonal antibodies reacted with purified lipopolysaccharides from E. coli J5, the deep rough mutant Salmonella minnesota Re595, Agrobacterium tumefaciens, and Pseudomonas aeruginosa PAO1 as well as with the purified lipid A of P. aeruginosa. Enzyme-linked immunosorbent assays using the outer membranes from a variety of gram-negative bacteria demonstrated that these lipid A-specific monoclonal antibodies interacted with between 84 and 97% of the gram-negative bacterial species tested. One of the monoclonal antibodies, 5E4, was shown to interact with 34 of the 35 outer membrane or lipopolysaccharide antigens tested. Immunoenzymatic staining of Western electrophoretic blots of separated P. aeruginosa outer membrane components was used to demonstrate that antibody 5E4 interacted with a similar fast-migrating band, corresponding to rough lipopolysaccharide, from all 17 serotype strains and all 14 clinical isolates of P. aeruginosa. Similarly, iodinated goat anti-mouse immunoglobulin was used to detect the binding of monoclonal antibody 8A1 to a fast-migrating band on Western electrophoretic blots of purified lipopolysaccharides from Klebsiella pneumoniae and both smooth and rough strains of E. coli, Salmonella typhimurium, and S. minnesota. These results suggest considerable conservation of single antigenic sites in the lipid A of gram-negative bacteria.

Antibodies, Bacterial↗

PubMed1984

Antigenic S-type lipopolysaccharide of Brucella abortus 1119-3.

Antigenic phenol-phase soluble lipopolysaccharide isolated from Brucella abortus 1119-3 by hot phenol-water extraction was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, controlled hydrolysis, periodate oxidation, methylation, and 1H and 13C nuclear magnetic resonance studies to be an S-type lipopolysaccharide which could be cleaved to yield a lipid A and an O-chain polysaccharide identified as an unbranched linear homopolymer of 1,2-linked 4,6-dideoxy-4-formamido-alpha-D-mannopyranosyl residues. The serological reactivity of bovine antiserum to B. abortus 1119-3 with the lipopolysaccharides of Yersinia enterocolitica serotype O:9 and Vibrio cholerae species has now been related to the occurrence of 1,2-linked N-acylated 4-amino-4,6-dideoxy-alpha-D-mannopyranosyl units in the O-chain polysaccharides of their lipopolysaccharides.

Antigens, Bacterial↗

PubMed1984

Mouse monoclonal antibodies reactive with J5 lipopolysaccharide exhibit extensive serological cross-reactivity with a variety of gram-negative bacteria.

We describe two mouse monoclonal antibodies reactive with lipopolysaccharide derived from the J5 mutant of Escherichia coli O111:B4. These antibodies react with purified lipopolysaccharide derived from rough mutants of E. coli and Salmonella typhimurium and also with lipopolysaccharide associated with both smooth- and rough-phenotype, gram-negative bacteria. Both antibodies appear to bind determinants present in the lipopolysaccharide core region, and this reactivity is inhibited in the presence of polymyxin B. Although their patterns of reactivity differ, both antibodies exhibit extensive serological cross-reactivity with a variety of gram-negative bacteria. Reagents of this type should prove useful in animal models to delineate the requisite affinity, epitope specificity, immunoglobulin class, etc., needed for the prevention and treatment of gram-negative bacteremia.

Animals↗

PubMed1985

Inhibition of serum bactericidal reaction by lipopolysaccharide.

An Rc-mutant of Escherichia coli that lacks UDPgalactose 4-epimerase grows normally without galactose but makes lipopolysaccharide lacking most of its carbohydrate. Exogenous galactose overrides the mutation and results in the formation of a complete lipopolysaccharide, thereby producing a smooth phenocopy. The smooth phenocopy was much more resistant to the bactericidal activity of normal human serum than was the rough phenotype. More complement was utilized by the rough mutant in the bactericidal process than by the smooth phenocopy. An antiserum was prepared in rabbits to a specific outer membrane protein in the mutant bacterium, the lambda receptor, whose expression could be suppressed by the addition of 10 mM maltose. The effect of the O-antigen in the lipopolysaccharide produced by the smooth phenocopy on the binding of antibody to the lambda receptor was determined. The smooth phenocopy exhibited significantly less binding of antibody than did the rough phenocopy. In addition, expression of the lambda receptor had little effect on the binding of antibody to the lambda receptor in the smooth phenocopy but caused significantly increased binding in the rough mutant. The results suggest that the increased resistance to the lethal action of normal human serum shown by the smooth phenocopy may be due to the blocking of antibody binding sites by the O-antigen of lipopolysaccharide, thereby preventing activation of the classical pathway of complement.

Antibodies, Viral↗

PubMed1971

Dissociation and reassembly of Escherichia coli outer membrane and of lipopolysaccharide, and their reassembly onto flagellar basal bodies.

Purified lipopolysaccharide vesicles dissociate when treated with ethylenediaminetetraacetic acid (EDTA) and then reassemble when dialyzed against Mg(2+). Purified outer, lipopolysaccharide membrane (L membrane) is partially dissociated by treatment with EDTA and fully dissociated upon further treatment with Triton X-100. Both the partially and fully dissociated L membrane can be reassembled by dialysis against Mg(2+). Reassembly of lipopolysaccharide or L membrane in the presence of intact flagella results in specific attachment of flagellar basal bodies to vesicles via the L and sometimes the M ring. Lipopolysaccharide and L membrane appear to be composed of substructures bound together by both Mg(2+) (divalent cation)-mediated and hydrophobic bonds.

Bacterial Proteins↗

PubMed1973

Lipopolysaccharide layer protection of gram-negative bacteria against inhibition by long-chain fatty acids.

Growth, amino acid transport, and oxygen consumption of Escherichia coli and Salmonella typhimurium are inhibited by short-chain (C(2)-C(6)) but not by medium or long-chain fatty acids (C(10)-C(18)) at concentrations at which these processes are completely inhibited in Bacillus subtilis. The resistance of gram-negative organisms is not correlated with their ability to metabolize fatty acids, since an E. coli mutant unable to transport oleic acid is still resistant. However, mutants of both E. coli and S. typhimurium in which the lipopolysaccharide layer does not contain the residues beyond the 2-keto-3-deoxyoctonate core are inhibited by medium (C(10)) but not by long-chain (C(18)) fatty acids. Furthermore, removal of a portion of the lipopolysaccharide layer by ethylenediaminetetraacetate treatment renders the organisms sensitive to medium and partially sensitive to long-chain fatty acids. The intact lipopolysaccharide layer of gram-negative organisms apparently screens the cells against medium and long-chain fatty acids and prevents their accumulation on the inner cell membrane (site of amino acid transport) at inhibitory concentrations. These results are relevant to the use of antimicrobial food additives, and they allow the characterization of gram-positive versus gram-negative bacteria and their lipopolysaccharide mutants.

Bacillus subtilis↗

PubMed1974

Structure of O-specific side chains of lipopolysaccharides from Yersinia pseudotuberculosis.

Lipopolysaccharide prepared from cells of Yersinia (Pasteurella) pseudotuberculosis of serogroups I, II, III, IV, and V is known to contain the 3,6-dideoxyhexose (DDH) paratose, abequose, paratose, tyvelose, and ascarylose in its respective O-specific side chains. Lipopolysaccharides or lipid-free polysaccharides of all of the 10 known serogroups and subgroups were subjected to methylation analysis and determined as alditol acetates by gas-liquid chromatography and mass spectrometry. The results indicated that the O-specific side chains of nine serotypes are composed of oligosaccharide repeating units in the form of four alternative general structures in which a terminal DDH may vary. These structures are DDH [Formula: see text] 6-deoxy-d-manno-heptose [Formula: see text] d-galactose (serogroups IA, IIA, and IVB), DDH [Formula: see text] d-mannose [Formula: see text] l-fucose (serogroups IB and IIB), and two configurations similar to the latter except that the 4-position of l-fucose was either linked to the d-mannose residue (serogroups VA and VB) or to the DDH residue (serogroups III and IVA). In contrast, O-groups in lipopolysaccharide of the newly discovered serogroup VI contained the DDH colitose and 2-acetamido-2-deoxy-d-galactose. Accordingly, all five known types of DDH have now been detected in lipopolysaccharides of Y. pseudotuberculosis. The sugar 6-deoxy-d-manno-heptose, present in O-specific side chains of serogroups IA, IIA, and IVB, has not yet been reported to occur elsewhere in nature.

Chemical Phenomena↗

PubMed1974

Genetic analysis of Salmonella minnesota R mutants with defects in the biosynthesis of the lipopolysaccharide core.

A set of R (rough) mutants, in which the synthesis of the cell wall lipopolysaccharide is defective, were analyzed genetically. These same Salmonella minnesota mutants have been used extensively in biochemical studies. By combining the information from all these studies, we obtained a complete genetic description of many of these mutants. Most of them turned out to be double rfe rfa mutants in which the rfe mutation (close to ilv) accounts for inability to synthesize O-specific structures and the rfa mutation accounts for defects in the synthesis of the core and, thus, for the lipopolysaccharide chemotype. These mutants demonstrate that in S. minnesota of O group L, as well as in S. typhimurium of the O group B, the rfb gene cluster close to his determines the synthesis of the O-specific side chain of the lipopolysaccharide, and the rfa genes in a cluster close to pyrE determine the synthesis of the lipopolysaccharide core. Phosphorylation of the core is determined by a rfaP gene also in this cluster and so far identified only by these S. minnesota mutants. In addition, the rfe gene(s) close to ilv is required for O-side chain synthesis in S. minnesota but not in S. typhimurium.

Cell Wall↗

PubMed1977

Identification of lipopolysaccharides and phospholipids of Escherichia coli in polyacrylamide gels.

Polyacrylamide gel electrophoresis of unfractionated lysates of radioactively labeled cells resolves not only proteins and polynucleotides into discrete bands but also cellular lipopolysaccharides and phospholipids. This allows a determination of the intracellular amounts of all of these macromolecules. In addition, this technique is sensitive enough to detect mutational alterations in lipopolysaccharide structure. Polyacrylamide gel electrophoresis is herein shown to be a useful tool for investigations into the structure of lipopolysaccharides and the synthesis of lipopolysaccharides and phospholipids.

Electrophoresis, Polyacrylamide Gel↗

PubMed1981

Influence of lipopolysaccharide and protein in the cell envelope on recipient capacity in conjugation of Salmonella typhimurium.

In crosses of Salmonella typhimurium FfinP301 lac+ to F- strains of S. typhimurium in broth, recipient strains which were rough mutants affected in the outer core region of the lipopolysaccharide gave an average of 1.4 Lac+ transconjugants per donor cell and over 50% of the donor and recipient cells in mating aggregates, whereas smooth recipient strains gave 0.08 Lac+ transconjugants and few cells in mating aggregates. Strains with mutations affecting the inner core of the lipopolysaccharide were usually poor recipients. When cells were mated on Millipore membrane filters, both smooth and rough strains gave ca. 1.0 Lac+ transconjugants per donor cell. Plasmids in Inc groups FI, FII, M, J, and I beta gave more transconjugants with rough than smooth strains, but there were no difference in crosses with plasmids in Inc groups T, L, P, N, and W. Strains with mutations in the ompA gene (deficient in Omp Ap = 33K = II* = conjugation protein) yielded only 0.02 Lac+ transconjugants per donor cell and few cells in mating aggregates. There was no indication of a deficiency of Omp Ap in smooth strains compared with rough strains. Reduced fertility of smooth recipients may occur because the O side chains of the lipopolysaccharide shield the recipient and reduce the frequency of stabilization of mating aggregates. However, gradient-of-transmission experiments indicated that once these mating aggregates are stabilized, they are equally stable in both smooth and rough recipients. Fertility was high in crosses of S. typhimurium Flac+ to Escherichia coli K-12 F- (0.75 Lac+ transconjugants per donor cell; over 50% of the cells in mating aggregates). In crosses of E. coli K-12 Flac+ to S. typhimurium smooth F-, ca. 10(-5) Lac+ transconjugants per donor cell were obtained; in crosses to rough recipient strains, fertility was increased 14-fold, and when the recipient was defective in the SA and LT host restriction systems, fertility was increased in additional 100-fold. Thus, both the lipopolysaccharide and the protein in the cell envelope of S. typhimurium were shown to be important in the recipient function in F-mediated conjugation.

Bacterial Proteins↗

PubMed1984

Serum-resistant mutants of Escherichia coli O111 contain increased lipopolysaccharide, lack an O antigen-containing capsule, and cover more of their lipid A core with O antigen.

Escherichia coli strains of group O111 were characterized with respect to sensitivity to complement killing, amount of lipopolysaccharide and O antigen-containing capsule, and distribution of O antigen. All wild-type E. coli O111 strains were resistant to complement killing in the absence of specific antibody. Presensitization of strains with antibody to whole cells (OK antibody), followed by incubation in 50% pooled normal human serum as a source of complement, subdivided wild-type strains into three types: completely resistant, partially resistant, and sensitive. Completely and partially resistant mutants were isolated by cycles of serum killing, starting with one sensitive strain. Completely resistant mutants had no O antigen-containing capsule, but had 50% more lipopolysaccharide than did the parent, and this lipopolysaccharide had 30% fewer lipid A core molecules devoid of O antigen. Partially resistant mutants still had O antigen-containing capsule, but contained 40% more lipopolysaccharide than did the parent; the extent of coverage of lipid A core with O antigen remained unchanged. No correlations were found between outer membrane protein composition and the degree of serum resistance. Since the terminal membrane attack complex (C5b-9) must stably insert into a hydrophobic membrane site to effect killing, we conclude that both increased lipid A core and increased coverage of lipid A core with O antigen preclude access of C5b-9 to lethal sites on the cell surface.

Antigens, Bacterial↗

PubMed1985

High-molecular-weight components in lipopolysaccharides of Salmonella typhimurium, Salmonella minnesota, and Escherichia coli.

Lipopolysaccharide from smooth strains of Salmonella typhimurium, Salmonella minnesota, and Escherichia coli O111:B4, O55:B5, and O127:B8 was fractionated by gel filtration chromatography. All lipopolysaccharide samples separated into three major populations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the fractions from S. typhimurium and S. minnesota indicated that the three peaks were made up of molecules with average O-antigen lengths of (i) 70 or more repeat units, (ii) 30 and 20 repeats units in the samples from S. typhimurium and S. minnesota, respectively, and (iii) 1 repeat unit. In contrast to the Salmonella samples, peak 1 from the E. coli samples was not detected on polyacrylamide gels and lacked detectable phosphate. This high-molecular-weight material had a sugar composition similar to that of O-antigen and was tentatively identified as capsular polysaccharide. Peaks 2 and 3 of the E. coli samples were analogous to those of the Salmonella isolates, containing lipopolysaccharide molecules with averages of 18 and 1 O-antigen repeat units, respectively. These lipopolysaccharide molecules did not completely dissociate during electrophoresis, and multimers were detected as distinct, anomalous, slow-migrating bands. Increasing the concentration of sodium dodecyl sulfate in the gels resulted in the dissociation of these multimers.

Antigens, Bacterial↗