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)

Serum from volunteer subjects vaccinated with a bivalent whole cell vaccine of Leptospira interrogans serovar hardjo/serovar pomona grown in protein-free medium, was tested by the microscopic agglutination test (MAT), enzyme-immunoassay (EIA) and immunoblotting. Specific IgM antibodies to either serovars hardjo or pomona were detected in some subjects as early as 6 days after vaccination with peak antibody levels occurring 13-68 days after vaccination. Whereas all subjects produced specific IgM to both serovars, not all produced specific IgG to both serovars. Immunoblotting with hardjo sonicate revealed that all subjects produced IgM antibodies reacting with the 15, 23 and 28 kDa components of hardjo lipopolysaccharide (LPS), and most produced IgM antibodies that reacted with the 34.5 kDa flagellar doublet. In contrast, not all sera immunoblotted against pomona sonicate reacted with the 29 and 35 kDa components of pomona LPS. However all subjects produced antibodies reacting with a diffuse 14.4-27 kDa band. These antibodies appeared early in the immune response. Serum from the one vaccinated subject tested protected hamsters from acute lethal infection with serovar pomona.
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PMID:Antigens recognized by the human immune response to vaccination with a bivalent hardjo/pomona leptospiral vaccine. 225 62

The pathway of interleukin 1 (IL-1) secretion from the cell remains unclear. IL-1 beta is the major form produced by human monocytes, and is synthesized as a precursor of 35 kDa which is processed to the extracellular biologically active 17 kDa form. We have examined the intracellular localization of IL-1 beta in lipopolysaccharide (LPS)-stimulated human peripheral blood monocytes, by immunocytochemistry and immunoprecipitation of subcellular fractions. LPS treatment slightly damaged the cells. Unstimulated cells showed very little immunolabelling. In contrast, there was heavy immunolabelling on LPS stimulated cells. Immunolabelling occurred within the cytoplasm, nucleus and mitochondria. There was no immunolabelling on the membranous secretory organelles and the plasma membrane. Blebs of cytoplasm budding from the cell surface were immunolabeled, suggesting an alternative route of secretion of IL-1 beta from the cell. Immunoprecipitation studies confirmed these results.
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PMID:Ultrastructural localization of interleukin 1 in human peripheral blood monocytes; evidence for IL-1 beta in mitochondria. 238 58

T lymphocyte-mediated immunity is important for resistance to Francisella tularensis. To characterize the specificity of this immunity, we used membrane proteins and two lipopolysaccharide (LPS) preparations. Both membrane proteins were heat-modifiable, as indicated by their migration in sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). One had an apparent molecular mass (Mm) of 120 kilodaltons (kDa) when solubilized in the SDS buffer at room temperature, but 17 kDa after heating. The respective values for the other protein were 35 kDa before and 40 kDa after heating. Both proteins were purified by a preparative SDS-PAGE. The LPS-containing preparations were isolated by aqueous phenol (WP) or PCP (phenol-chloroform-petroleum ether) extraction (LPS-R), and rendered protein-free by treatment with proteinase K. Lymphocytes from nine subjects immunized with a live tularemia vaccine from one to three years earlier responded specifically to both an F. tularensis whole cell antigen and the 17 kDa protein in the lymphocyte blast transformation test. By contrast, the 40 kDa protein and the two LPS preparations did not stimulate any detectable lymphocyte proliferation.
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PMID:Membrane proteins of Francisella tularensis LVS differ in ability to induce proliferation of lymphocytes from tularemia-vaccinated individuals. 262 30

VCAM-1 is a cytokine-induced endothelial adhesion molecule which belongs to the immunoglobulin (Ig) superfamily and mediates the binding of various leukocytes. In addition to the 110-kDa form of VCAM-1, we have found four additional glycoproteins on mouse brain-derived endothelioma cells after stimulation with tumor necrosis factor-alpha (TNF-alpha), which are recognized by several monoclonal antibodies against VCAM-1. Biochemical analysis revealed that the two smaller proteins (35 kDa and 37 kDa) are intracellular precursors of the two larger forms (44 kDa and 45 kDa), that the 44 kDa and 45 kDa proteins are glycolipid-anchored at the cell surface and that they differ in their N-glycosylation. Most likely they are identical to the recently identified glycolipid-anchored splice variant of VCAM-1, since they are recognized by the M3 antiserum which we raised against a peptide from the unique protein domain of this splicing variant. With the help of this antiserum we could show by immunohistology that the corresponding VCAM-1 protein variant is induced in vivo by lipopolysaccharide (LPS) on endothelium of the mouse. In addition, we found a 42-kDa soluble form of VCAM-1 in the serum of LPS-stimulated mice, which was recognized by the M3 antiserum. This soluble form was undetectable in the serum of unstimulated mice in contrast to the soluble 100-kDa form of VCAM-1 which was clearly detected in serum of unstimulated mice and only increased 2-3-fold upon stimulation with LPS. Thus, only the expression of the 42-kDa shredded form and not of the 100-kDa soluble form of VCAM-1 is strictly dependent on stimulation by LPS.
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PMID:A novel soluble form of mouse VCAM-1 is generated from a glycolipid-anchored splicing variant. 750 45

Roseobacter denitrificans has rough (R)-type lipopolysaccharide, containing 2-keto-3-deoxyoctonate but no hepatoses. Its lipid A has a glucosamine-containing, phosphorylated backbone. It contains the rare 3-oxotetradecanoic (3-oxomyristic) acid as the only amide-bound fatty acid and ester-bound 3-hydroxydecanoic acid, this pattern being characteristic for the alpha-3 subgroup of Proteobacteria. Treatment of the major outer-membrane protein (porin, apparent molecular mass 88 kDa) of Roseobacter denitrificans with EDTA (2 mM, 30 degrees C, 20 min) resulted in the dissociation of the oligomers into monomers (apparent molecular mass 35 kDa). EDTA-sensitive dissociation has so far been observed only within the alpha-3 subgroup of Proteobacteria. The 12 N-terminal amino acids of the monomers exhibit sequence homology with the porins of Rhodobacter capsulatus, Rhodobacter sphaeroides and Rhodopseudomonas blastica. Renaming of Roseobacter denitrificans as Rhodobacter denitrificans is suggested.
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PMID:Lipopolysaccharide and porin of Roseobacter denitrificans, confirming its phylogenetic relationship to the alpha-3 subgroup of Proteobacteria. 755 Oct 64

This investigation was to determine whether Pseudomonas aeruginosa could acquire resistance to the bactericide isothiazolone, and what the nature of such a resistance mechanism would be. The Pseudomonas was cultured in nutrient-limited broth in the presence of sub-inhibitory concentrations of isothiazolone (a mixture of 1.15% 5-chloro-N-methylisothiazolone (CMIT) and 0.35% N-methylisothiazolone (MIT)). Three cultures tested in parallel adapted gradually during exposure for 15 d from an initial minimum inhibitory concentration (MIC) of 300 microliters l-1 to 607 microliters l-1. The three parallel cultures adapted at similar rates, so the adaptation was not ascribed to mutation but to a specific mechanism. Resistant cells did not produce any extracellular isothiazolone-quenching compounds nor undergo detectable alterations in their lipopolysaccharide layer. In wild cells, a 35 kDa outer membrane protein (protein T) was detectable, whereas resistant cells lacked this protein. Production of protein T was suppressed within 24 h of exposure to isothiazolone. It was still suppressed after 72 h of growth in isothiazolone-free medium. It is proposed that Ps. aeruginosa acquires resistance to isothiazolone by a process of adaptation where the outer membrane protein T is suppressed.
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PMID:Resistance of Pseudomonas aeruginosa to isothiazolone. 802 6

Tumor necrosis factor-alpha (TNF alpha) is a biologically active cytokine with a wide range of functions, which is primarily expressed by macrophages. It is produced as a biologically active propeptide that becomes processed to the mature form of secreted protein. Previous studies used a mouse macrophage cell line and showed that after stimulation with lipopolysaccharide, TNF alpha propeptide is expressed as multiple isoforms with approximate molecular masses of 26, 29 and 32 kDa. However, little is known of the production of TNF alpha isoforms from normal macrophages or of the effects of cytokines on TNF alpha production by macrophages in the absence of co-stimulation by lipopolysaccharide. We have compared the TNF alpha isoforms produced by cytokine-and lipopolysaccharide-stimulated bone marrow-derived macrophages from mice that normally respond to lipopolysaccharide (C3H/HeN) and mice that are hyporesponsive (C3H/HeJ). We found that the pattern of immunoprecipitated TNF alpha propeptide isoforms expressed depended on the stimulus: lipopolysaccharide, granulocyte-macrophage colony-stimulating factor or macrophage colony-stimulating factor. Lipopolysaccharide induced three isoforms of 25, 29 and 35 kDa, supporting previous studies. However, macrophage and granulocyte-macrophage colony-stimulating factors also stimulated cells to express the 24 and 27 kDa isoforms, but not the 35 kDa isoform. In addition, cells stimulated with granulocyte-macrophage colony-stimulating factor expressed a novel 20 kDa propeptide. The results show that granulocyte-macrophage colony-stimulating factor, macrophage colony-stimulating factor and lipopolysaccharide differently regulate TNF alpha protein expression and suggest that different isoforms may have different functions.
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PMID:Differential expression of tumor necrosis factor-alpha isoforms from lipopolysaccharide- and cytokine-stimulated mouse macrophages. 881 44

Four Klebsiella pneumoniae isolates (LB1, LB2, LB3, and LB4) with increased antimicrobial resistance were obtained from the same patient. The four isolates were indistinguishable in biotype, plasmid content, lipopolysaccharide, and DNA analysis by pulse-field gel electrophoresis. Isolate LB1 made TEM-1 and SHV-1 beta-lactamases. Isolates LB2, LB3, and LB4 produced SHV-5 in addition to TEM-1 and SHV-1. MICs of cefoxitin, ceftazidime, and cefotaxime against LB1 were 4, 1, and 0.06 micrograms/ml, respectively. MICs of ceftazidime against K. pneumoniae LB2, LB3, and LB4 were > 256 micrograms/ml, and those of cefotaxime were 2, 4, and 64 micrograms/ml, respectively. MICs of cefoxitin against K. pneumoniae LB2 and LB3 were 4 micrograms/ml, but that against K. pneumoniae LB4 was 128 micrgrams/ml. K. pneumoniae LB4 could transfer resistance to ceftazidime and cefotaxime, but not that to cefoxitin, to Escherichia coli. Isolate LB4 and cefoxitin-resistant laboratory mutants lacked an outer membrane protein of about 35 kDa whose molecular mass, mode of isolation, resistance to proteases, and reaction with a porin-specific antiserum suggested that it was a porin. MICs of cefoxitin and cefotaxime reverted to 4 and 2 micrograms/ml, respectively, when isolate LB4 was transformed with a gene coding for the K. pneumoniae porin OmpK36. We conclude that the increased resistance to cefoxitin and expanded-spectrum cephalosporins of isolate LB4 was due to loss of a porin channel for antibiotic uptake.
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PMID:In vivo selection of porin-deficient mutants of Klebsiella pneumoniae with increased resistance to cefoxitin and expanded-spectrum-cephalosporins. 1137 40

Salmonella enterica Enteritidis in chickens serves as a reservoir for salmonellosis in humans and the structure of its lipopolysaccharide (LPS) has been used to assess invasiveness. Culture from chick spleens generated colonies with an unusual wrinkled morphology, and it is designated the lacy phenotype. The characterize the nature of the morphological change, three isogenic variants were compared. Only the lacy phenotype produced a temperature-dependent cell surface matrix composed of several proteins in association with LPS high molecular weight O-antigen. Flagellin and a 35 kDa protein were identified as specific proteinaceous components of matrix. Both proteins cross-reacted with a monoclonal antibody previously determined to specifically detect the g-epitope of the Enteritidis monophasic flagella (H-antigen). These results suggest that O-antigen in association with protein contributes to cross-reactivity between molecules. The lacy phenotype was more organ invasive in 5-day-old chicks than isogenic variants producing low molecular weight O-antigen. However, it was no more efficient at contaminating eggs after oral inoculation of hens than a variant that completely lacked O-antigen, thus the lacy phenotype is classified as an intermediately invasive organism. The distinctive colonial phenotype of SE6-E21lacy was used to investigate environmental factors that decreased O/C ratios and contributed to attenuation. In so doing, it was found that growth in complement at 46 degrees C caused matrix producing cells to hyperflagellate and migrate across agar surfaces. These results suggest that the structure of O-antigen might influence the secretion and/or the function of Enteritidis cell-surface proteins. The data also reveal a greater heterogeneity than has been assumed in the phenotype, and possibly the infectious behaviour, of Enteritidis.
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PMID:A novel relationship between O-antigen variation, matrix formation, and invasiveness of Salmonella enteritidis. 887 Jun 19

Tyrosine phosphorylation is an important mechanism of cell regulation and has been recently implicated in defense strategies against a variety of pathogens. We have investigated the involvement of protein tyrosine kinase activity in the Leishmania attachment, invasion and survival within macrophages, as well as promastigote ability to trigger tyrosine phosphorylation, which could contribute to leishmanicidal activity. Treatment of murine macrophage monolayers with genistein, herbimycin A, tyrphostin 25 or staurosporine prior to infection decreased parasite invasion in a dose-dependent manner. Contrary, addition of sodium orthovanadate, a protein tyrosine phosphatase inhibitor, phosphotyrosine and p-nitrophenyl phosphate to the interaction medium, significantly increased parasite binding and internalization, whereas phosphoserine and phosphothreonine had no effect. The phosphatase activity of intact promastigotes was greater than that of macrophages. Western blot analysis revealed tyrosine-phosphorylated bands from 198 to 28 kDa following macrophage challenge with promastigotes. Uninfected macrophages displayed no detectable tyrosine phosphorylated proteins, possibly indicating an inducible process, while in parasites it was constitutive, as seen by the presence of 42, 40 and 35 kDa phosphoproteins on the Leishmania lysates. Immunofluorescence and immunogold detection of phosphotyrosine residues in some promastigote-macrophage attachment areas, but not in the vicinity of ingested parasites, suggest that Leishmania-induced tyrosine phosphorylation is an early, local and short-lived event. Genistein treatment of Leishmania-infected cells significantly enhanced the parasite burden. This antagonist also diminished nitric oxide production in resting and interferon gamma/lipopolysaccharide-activated infected macrophages, which may account for the increased parasite survival. We propose that protein tyrosine kinase-linked pathways regulate the Leishmania promastigote invasion and the macrophage microbicidal activity.
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PMID:Leishmania-induced tyrosine phosphorylation in the host macrophage and its implication to infection. 890 99


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