Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lysates obtained from amoebocytes of Limulus polyphemus, the horseshoe crab, showed gel formation after the addition of bacterial endotoxin. In contrast to living gram-negative bacteria, viable gram-positive microorganisms did not cause gelation of lysate. Nevertheless, peptidoglycan isolated from the cell walls of various gram-positive organisms did induce the reaction. However, the activity of peptidoglycan was 1,000 to 400,000 times less than that of Escherichia coli lipopolysaccharide. After exposure to lysozyme, peptidoglycan no longer gelled amoebocyte lysate, therefore apparently excluding endotoxin contamination. Gelation of amoebocyte lysate by endotoxin or peptidoglycan was inhibited by different concentrations of sodium polystyrolsulfonate. Whereas these studies confirm the specificity of the Limulus test for bacterial endotoxins, they also indicate that other substances of bacterial origin should be investigated for their ability to gel amoebocyte lysate.
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PMID:Investigations on the specificity of the Limulus test for the detection of endotoxin. 461 71

When antibody-sensitized Escherichia coli B is treated with complement in the absence of lysozyme, bacterial phospholipids or fragments containing phospholipid appear in the surrounding medium. Almost at the start of the reaction, a little phosphatidylethanolamine (PE) appears in the lipid fraction extracted from the supernatant of the reaction mixture. Later it does not increase greatly in amount but free fatty acids (FFA) and lysophosphatidylethanolamine (LPE) appear and increase gradually. Addition of lysozyme to the reaction mixture changes the amounts of FFA and LPE released, but does not increase the numbers of the spots on a thin layer chromatogram of the lipid fraction of the supernatant. The FFA fraction contains no beta-hydroxymyristic acid from lipid A of the lipopolysaccharide complex.
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PMID:Chemical studies on damages of Escherichia coli by the immune bactericidal reaction. I. Release and degradation of phospholipids from damaged bacteria. 461 9

Chemical analysis of fractions of the cell envelope of Acinetobacter sp. strain MJT/F5/199A, prepared by breakage in the French press and removal of plasma membranes, followed by sequential treatment with lysozyme and with papain, confirmed the existence of layers previously identified by electron microscopy. Outside the plasma membrane and periplasmic space, the envelope is composed of (i) a peptidoglycan-containing dense layer, (ii) an intermediate layer, (iii) a lipopolysaccharide-containing outer membrane, and (iv) an ordered array of protein subunits. A small amount of carbohydrate (3%) is found associated with protein in the fraction containing both the surface subunits and the intermediate layer. The papain-treated outer membranes contain 67% protein, 24% lipid, together with 11% lipopolysaccharide, and about 6% of non-lipopolysaccharide hexosamine. Lipid is located only in the papain-treated outer-membrane and is mainly phospholipid: 29% phosphatidyl glycerol, 30% phosphatidyl ethanolamine, and 40% cardiolipin. The principal fatty acid is C(18:1). Significant amounts of alcohols(16:1) and alcohols(18:1), which are found in Acinetobacter waxes, were recovered from the outer membrane.
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PMID:Chemical analysis of the outer membrane and other layers of the cell envelope of Acinetobacter sp. 474 22

The antibacterial action of antibody (normal and hyperimmune), complement, and lysozyme has been studied by correlating the ultrastructural and biochemical changes that they cause in smooth Escherichia coli. Both normal and hyperimmune antibody, in the absence of lysozyme, produced complement-dependent release, into the suspending medium, of 63 to 72% of the (32)P-labeled phospholipid and 74 to 85% of the small molecular bacterial constituents. Macromolecular nucleic acid labeled with (32)P was not released. By phase microscopy, these cells appeared as bacilli but their ultrastructure showed general swelling, with smoothing of the normally wrinkled outer cell wall layers. Cytoplasmic membranes were damaged and the internal cell structure was disorganized. Membranous spherules, apparently from the outermost putatively lipopolysaccharide cell layer, were released into the medium. When lysozyme was added to antibody and complement, (32)P-labeled macromolecular constituents were released from the cells. Damage to ultrastructure then included loss of cell wall rigidity, cell wall breakage, and some spheroplast formation. Characteristic fibrillar fragmentation was seen in cell wall mucopeptide layers. The relationships between antibody-complement dependent release of bacterial phospholipid, loss of selective cell permeability, and increase in sensitivity to lysozyme are discussed.
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PMID:Molecular and structural damage to Escherichia coli produced by antibody, complement, and lysozyme systems. 487 62

Knox, K. W. (Twyford Laboratories, London, England), Maret Vesk, and Elizabeth Work. Relation between excreted lipopolysaccharide complexes and surface structures of a lysine-limited culture of Escherichia coli. J. Bacteriol. 92:1206-1217. 1966.-The lysine-requiring mutant Escherichia coli 12408, when grown in 15 liters of defined medium containing a suboptimal amount of lysine, showed a biphasic type of growth. During a long stationary phase of 15 hr, there was a steady accumulation of diaminopimelic acid (DAP) and an antigenic complex of lipopolysaccharide (LPS) and lipoprotein; the accumulation continued unchanged until the end of the second growth phase. The rapid rate of DAP excretion suggested that it was the result of a derepressed state of a biosynthetic pathway. LPS excretion was such that the amount in the culture fluid was doubled during a period corresponding to the normal generation time for the organism; this suggested that the LPS-lipoprotein complex was a product of unbalanced growth. Surface defects were suggested by the action of lysozyme, which, in low concentrations (10 mug/ml), lysed the lysine-limited cells even in the absence of ethylenediaminetetraacetic acid, but had no effect at 10 mug/ml on cells grown with adequate lysine. Electron microscopy of cells excreting the LPS complex showed them to be surrounded by a mass of stacked leaflets and globules, some of which were bounded by triple membranes. Sections showed no lysis but changes in cell surfaces; outer layers of the walls had numerous blebs whose outer membranes were sometimes continuous with the outer triple membrane of the wall. LPS-lipoprotein probably originates from these blebs.
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PMID:Relation between excreted lipopolysaccharide complexes and surface structures of a lysine-limited culture of Escherichia coli. 495 44

The mechanism of the lethal action of human serum on a rough strain of Escherichia coli was investigated by use of serum with and without lysozyme, in medium of low and high osmotic pressure, with cells radioactively labeled in the peptidoglycan polymer, and by electron microscopy. The results suggested that there are two separate components in the bacterial cell wall that afford structural support for the cell. Lysozyme attacked one of these, the peptidoglycan polymer. Serum damaged the other, which is probably the peripherally located lipopolysaccharide-phospholipid complex. The cell wall damage caused by lysozyme-free serum promptly resulted in cell death under usual conditions. In plasmolyzed cells, however, the wall damage was not lethal, presumably because the membrane of the plasmolyzed cell was protected from secondary lethal changes which otherwise occur.
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PMID:Locus of the action of serum and the role of lysozyme in the serum bactericidal reaction. 497 18

A mutant (G11el) of Escherichia coli selected as being resistant to ampicillin and showing signs of an envelope defect was also found to be tolerant to colicins E2 and E3. The colicin tolerance of G11el could be partially repressed by Mg(2+) ions. Transition from tolerance to sensitivity and vice versa by shifting the concentration of Mg(2+) in the growth medium required several generations. This indicated that synthesis of new envelope material was needed for transition. Previous physiological results have indicated a change in the envelope lipopolysaccharide (LPS) of G11el. However, chemical analyses revealed no differences in carbohydrate composition between LPS from G11el and its parent strain G11al. Genetic experiments showed that the mutation in G11el is located at about 20 min on the E. coli K-12 chromosome. The mutation was dominant over wild type in partial diploids with the mutation located on the episome. Because colicin tolerance was the most striking phenotypic effect as a result of mutation in the actual locus, this gene will be named tolD until the exact gene product is known. Spheroplasts formed from G11al and G11el by ethylenediaminetetraacetate-lysozyme treatment did not adsorb colicin E2; however, penicillin spheroplasts of G11al and G11el were tolerant to colicin E2. Thus, colicin tolerance can be induced biochemically. It is suggested that colicin tolerance often is a secondary consequence of a change in the cell envelope.
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PMID:Colicin tolerance induced by ampicillin or mutation to ampicillin resistance in a strain of Escherichia coli K-12. 499 99

Extraction of a partially purified preparation of cell walls from Escherichia coli with the nonionic detergent Triton X-100 removed all cytoplasmic membrane contamination but did not affect the normal morphology of the cell wall. This Triton-treated preparation, termed the "Triton-insoluble cell wall," contained all of the protein of the cell wall but only about half of the lipopolysaccharide and one-third of the phospholipid of the cell wall. This Triton-insoluble cell wall preparation was used as a starting material in an investigation of several further treatments. Reextraction of the Triton-insoluble cell wall with either Triton X-100 or ethylenediaminetetraacetic acid (EDTA) caused no further solubilization of protein. However, when the Triton-insoluble cell wall was extracted with a combination of Triton X-100 and EDTA, about half of the protein and all of the remaining lipopolysaccharide and phospholipid were solubilized. The material which remained insoluble after this combined Triton and EDTA extraction still retained some of the morphological features of the intact cell wall. Treatment of the Triton-insoluble cell wall with lysozyme resulted in a destruction of the peptidoglycan layer as seen in the electron microscope and in a release of diaminopimelic acid from the cell wall but did not solubilize any cell wall protein. Extraction of this lysozyme-treated preparation with a combination of Triton X-100 and EDTA again solubilized about half of the cell wall protein but resulted in a drastic change in the morphology of the Triton-EDTA-insoluble material. After this treatment, the insoluble material formed lamellar structures. These results are interpreted in terms of the types of noncovalent bonds involved in maintaining the organized structure of the cell wall and suggest that the main forces involved are hydrophobic protein-protein interactions between the cell wall proteins and to a lesser degree a stabilization of protein-protein and protein-lipopolysaccharide interactions by divalent cations. A model for the structure of the E. coli cell wall is presented.
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PMID:Effect of ethylenediaminetetraacetic acid, Triton X-100, and lysozyme on the morphology and chemical composition of isolate cell walls of Escherichia coli. 500 Dec 5

The release of (32)P-labeled bacterial phospholipid from a smooth Escherichia coli by serum components depends on complement activated by antibody. Phospholipid release in excess antibody tends to be proportional to the concentration of complement as does the release of other cellular constituents. Phospholipids are not simply stripped off during cell lysis. Whereas 94% of the total phospholipid freed from E. coli by mechanical lysis sediments at centrifugal forces sufficient to sediment molecules of 10(6) molecular weight, similar centrifugation sediments only 50% of the phospholipid released by antibody-complement. In fact, after mechanical lysis more than 50% of the phospholipid sediments at velocities sufficient to bring down cell envelopes. Although the bulk of the bacterial phospholipid is located in the cell envelopes, isolated (32)P-labeled cell envelopes and phenol-extracted lipopolysaccharide fails to release phospholipids in the presence of antibody-complement. Moreover, ethylenediaminetetraacetic acid, which like antibody-complement causes loss of cellular selective permeability and prepares E. coli cell walls for the action of lysozyme, releases only small amounts of phospholipid from E. coli and these are sedimentable. The most likely mechanism of phospholipid release caused by antibody-complement appears to be the activation directly or indirectly of an enzyme which is present only in the intact cells.
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PMID:Characteristics of complement-dependent release of phospholipid from Escherichia coli. 500 85

The specificity of polyclonal mouse rheumatoid factors (RF) was analyzed by competition experiments with heat-aggregated mouse IgG subclasses. The RF spontaneously produced by three normal mouse strains (129/Sv, CBA/Ht, and C57Bl/6) and by two strains with autoimmune diseases (MRL/l and NZB) were found to consist of distinct non-cross-reactive antibody subpopulations each specific for one IgG subclass. The sera of the normal strains contained IgG1- and IgG2a-specific RF. The autoimmune strains produced an additional variety of RF that was specific for The autoimmune strains produced an additional variety of RF that was specific for IgG2b. Also, the RF secreted by spleen cells of various normal strains after in vitro polyclonal activation with lipopolysaccharide could be resolved into distinct subpopulations specific for IgG1 or IgG2a. These results were confirmed by the analysis of monoclonal RF derived from BALB/c, C57Bl/6, CBA/Ht, and 129/Sv mice: of 73 hybridomas with RF activity, 71 displayed a strict subclass specificity. The subclass predominantly recognized depended on the origin of the spleen cells used to generate the hybridomas. After polyclonal activation in vitro, a broad spectrum of different specificities was obtained with 16 RF specific for IgG1, 13 for IgG2a, and 4 for IgG2b. In contrast, 27 of 28 monoclonal RF derived from 129/Sv and BALB/c mice without prior polyclonal activation were specific for IgG2a, and of these 75% were allotype specific since they failed to react with IgG2a of the b allotype. These results demonstrate the importance of subclass specificity in the production of RF in vivo. With the exception of the IgG2b-specific clones, all these monoclonal RF reacted preferentially with heat-aggregated or antigen-bound IgG. Among the hybridomas generated by the fusion of in vitro polyclonally activated spleen cells of 4-wk-old mice, the frequency of clones with RF activity was at least 40 times higher than that of clones specific for mouse IgM, human IgG, ovalbumin, and hen lysozyme.
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PMID:Isotypic and allotypic specificity of mouse rheumatoid factors. 618 78


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