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

Interleukin-18 (IL-18) is a newly described cytokine, formerly called interferon-gamma (IFN-gamma)-inducing factor. In a simple 24-h human whole blood culture, IFN-gamma was produced by the combination of lipopolysaccharide (LPS) plus IL-18. To liberate cytokines in the leukocyte and red cell compartments, the detergent Triton X-100 was added to the entire blood culture. The combination of low concentrations of LPS plus IL-18 induced a 3- to 5-fold greater production of IFN-gamma than did either stimulant alone. Tumor necrosis factor-alpha (TNF-alpha), IL-6, and IL-8 were also produced. The presence of IL-10 completely suppressed the production of IFN-gamma and reduced that of TNF-alpha, IL-6, and IL-8. Thus, IFN-gamma, TNF-alpha, IL-8, and IL-6 are produced in a single whole blood culture, making correlations in the synthesis of a T helper type 1 cytokine and proinflammatory cytokines with disease activity possible in a single culture.
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PMID:Interleukin-18 enhances lipopolysaccharide-induced interferon-gamma production in human whole blood cultures. 981 45

We have recently demonstrated that the periodontopathogenic oral spirochete Treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (LOS). The aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases. An enriched lipoprotein fraction (dLPP) from T. denticola ATCC 35404 obtained upon extraction of the treponemes with Triton X-114 was found to stimulate the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-1 (IL-1) by mouse macrophages in a dose-dependent manner. Induction of NO by dLPP was at 25% of the levels obtained by Salmonella typhosa lipopolysaccharide (LPS) at similar concentrations, while IL-1 was produced at similar levels by both inducers. dLPP-mediated macrophage activation was unaffected by amounts of polymyxin B that neutralized the induction produced by S. typhosa LPS. dLPP also induced NO and TNF-alpha secretion from macrophages isolated from endotoxin-unresponsive C3H/HeJ mice to an extent similar to the stimulation produced in endotoxin-responsive mice. Purified T. denticola LOS also produced a concentration-dependent activation of NO and TNF-alpha in LPS-responsive and -nonresponsive mouse macrophages. However, macrophage activation by LOS was inhibited by polymyxin B. These results suggest that T. denticola lipoproteins and LOS may play a role in the inflammatory processes that characterize periodontal diseases.
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PMID:Activation of murine macrophages by lipoprotein and lipooligosaccharide of Treponema denticola. 1002 58

The effect of lactic acid on the outer membrane permeability of Escherichia coli O157:H7, Pseudomonas aeruginosa, and Salmonella enterica serovar Typhimurium was studied utilizing a fluorescent-probe uptake assay and sensitization to bacteriolysis. For control purposes, similar assays were performed with EDTA (a permeabilizer acting by chelation) and with hydrochloric acid, the latter at pH values corresponding to those yielded by lactic acid, and also in the presence of KCN. Already 5 mM (pH 4.0) lactic acid caused prominent permeabilization in each species, the effect in the fluorescence assay being stronger than that of EDTA or HCl. Similar results were obtained in the presence of KCN, except for P. aeruginosa, for which an increase in the effect of HCl was observed in the presence of KCN. The permeabilization by lactic and hydrochloric acid was partly abolished by MgCl(2). Lactic acid sensitized E. coli and serovar Typhimurium to the lytic action of sodium dodecyl sulfate (SDS) more efficiently than did HCl, whereas both acids sensitized P. aeruginosa to SDS and to Triton X-100. P. aeruginosa was effectively sensitized to lysozyme by lactic acid and by HCl. Considerable proportions of lipopolysaccharide were liberated from serovar Typhimurium by these acids; analysis of liberated material by electrophoresis and by fatty acid analysis showed that lactic acid was more active than EDTA or HCl in liberating lipopolysaccharide from the outer membrane. Thus, lactic acid, in addition to its antimicrobial property due to the lowering of the pH, also functions as a permeabilizer of the gram-negative bacterial outer membrane and may act as a potentiator of the effects of other antimicrobial substances.
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PMID:Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane. 1078 73

Nitric oxide (NO) has been reported to be involved in the regulation of pseudopodia formation, phagocytosis and adhesion in macrophages through the reorganization of actin. In the present study, we directly separated the globular (G) and filamentous (F) actin from quiescent or NO-stimulated macrophage-like cell line RAW 264.7 cells in order to investigate the dynamic redistribution of actin pools. We also focused on the regulatory mechanisms of actin assembly, induced by NO and its possible subsequent signaling pathway. We showed that predominant G-actin coexisted with Triton X-100-insoluble filamentous (TIF) and Triton X-100-soluble filamentous actin in resting RAW 264.7 cells. The exogenous NO produced by (+/-)-(E)-2-[(E)-hydroxyimino]-6-methoxy-4-methyl-5-nitro-3-hexenamide (NOR1), the endogenous NO induced by lipopolysaccharide (LPS) plus interferon-gamma (IFNgamma), and dibutyryl-cGMP increased the contents of TIF-actin in dose- and time-dependent manners and altered its morphology. The increase in the TIF-actin contents induced by NOR1 or LPS plus IFNgamma was efficiently blocked by the radical scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide and the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one or the arginine analogue N(G)-monomethyl-L-arginine acetate, respectively. Preincubation with the calmodulin antagonist W-7 almost completely blocked the NO-induced TIF-actin increase and morphological change. On the other hand, preincubation with C3 transferase, an inhibitor of Rho protein, efficiently prevented the change in cell morphology, but had no effect on the TIF-actin increase. We postulate that cGMP and subsequent Ca(2+)/calmodulin may be key regulators of actin reorganization in NO-stimulated RAW 264.7 cells.
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PMID:Nitric oxide regulates actin reorganization through cGMP and Ca(2+)/calmodulin in RAW 264.7 cells. 1138 72

Leptospira is the etiologic agent of leptospirosis, a bacterial zoonosis distributed worldwide. Leptospiral lipopolysaccharide is a protective immunogen, but the extensive serological diversity of leptospires has inspired a search for conserved outer membrane proteins (OMPs) that may stimulate heterologous immunity. Previously, a global analysis of leptospiral OMPs (P. A. Cullen, S. J. Cordwell, D. M. Bulach, D. A. Haake, and B. Adler, Infect. Immun. 70:2311-2318, 2002) identified pL21, a novel 21-kDa protein that is the second most abundant constituent of the Leptospira interrogans serovar Lai outer membrane proteome. In this study, we identified the gene encoding pL21 and found it to encode a putative lipoprotein; accordingly, the protein was renamed LipL21. Southern hybridization analysis revealed the presence of lipL21 in all of the pathogenic species but in none of the saprophytic species examined. Alignment of the LipL21 sequence from six strains of Leptospira revealed 96 to 100% identity. When specific polyclonal antisera to recombinant LipL21 were used, LipL21 was isolated together with other known leptospiral OMPs by both Triton X-114 extraction and sucrose density gradient membrane fractionation. All nine strains of pathogenic leptospires investigated by Western blotting, whether culture attenuated or virulent, were found to express LipL21. In contrast, the expression of LipL21 or an antigenically related protein could not be detected in nonpathogenic L. biflexa. Infected hamster sera and two of eight human leptospirosis sera tested were found to react with recombinant LipL21. Native LipL21 was found to incorporate tritiated palmitic acid, consistent with the prediction of a lipoprotein signal peptidase cleavage site. Biotinylation of the leptospiral surface resulted in selective labeling of LipL21 and the previously known OMPs LipL32 and LipL41. These findings show that LipL21 is a surface-exposed, abundant outer membrane lipoprotein that is expressed during infection and conserved among pathogenic Leptospira species.
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PMID:LipL21 is a novel surface-exposed lipoprotein of pathogenic Leptospira species. 1270 11

Rafts resemble cholesterol- and glycosphingolipid-enriched, liquid-ordered plasma membrane microdomains, showing resistance to nonionic detergents, and are involved in various cellular processes. In the present study, we have tested surface antigens on resting and lipopolysaccharide (LPS)-stimulated human peripheral blood monocytes for their detergent resistance (i.e. raft-association), by flow cytometry. Constitutive (CD14, CD32, CD55), or LPS-induced (CD81) raft-association, and detergent solubility (i.e. exclusion of rafts) (CD71) of monocyte antigens in the presence of 0.01% Triton X-100 are clearly demonstrated. Flow cytometric detergent insolubility is a powerful tool for rapid screening the raft-association of monocyte antigens in a whole-blood assay.
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PMID:A flow cytometric screening test for detergent-resistant surface antigens in monocytes. 1647 17

Pathogenic Leptospira species adapt to a wide range of environmental conditions during disease transmission and infection. While the proteome of in vitro cultivated Leptospira has been characterized in several studies to date, relatively little is known of the proteome as expressed by Leptospira during disease processes. Isolates of Leptospira obtained from patients suffering the severe pulmonary form of leptospirosis cause acute lethal infection in guinea pigs and chronic asymptomatic infection in rats. Recent studies have demonstrated that protein and lipopolysaccharide constituents of Leptospira recovered from acutely infected guinea pig tissue differ from that of Leptospira in chronically infected rat tissue and in vitro cultivated Leptospira (J. E. Nally, E. Chow, M. C. Fishbein, D. R. Blanco, and M. A. Lovett, Infect. Immun. 73:3251-3260, 2005). In the current study, the proteome of Leptospira expressed during disease processes was characterized relative to that of in vitro cultivated Leptospira (IVCL) after enrichment for hydrophobic membrane proteins with Triton X-114. Protein samples were separated by two-dimensional gel electrophoresis, and antigens expressed during infection were identified by immunoblotting with monospecific antiserum and convalescent rat serum in addition to mass spectrometry. Results suggest a significant increase in the expression of the outer membrane protein Loa22 during acute infection of guinea pigs relative to other outer membrane proteins, whose expression is generally diminished relative to expression in IVCL. Significant amounts of LipL32 are also expressed by Leptospira during acute infection of guinea pigs.
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PMID:Characterization of the outer membrane proteome of Leptospira interrogans expressed during acute lethal infection. 1710 64

Bioactive pectic polysaccharides from Chinese herbs were tested for the presence of lipopolysaccharide (LPS) or LPS-like substances by chromogenic Limulus amebocyte lysate (LAL)-assay. Pectic polysaccharides from BUPLEURUM FALCATUM, GLYCYRRIZA URALENSIS, and ANGELICA ACUTILOBA were LAL-positive at different rates. The fractions GR-2IIc/PG-1 (ramified region; rhamnogalacturonan core with neutral sugar side chains) from G. URALENSIS and AGIIb-1 (acidic arabinogalactan) from A. ACUTILOBA activated the endotoxin-mediated coagulation factor (factor C). When the pectin-like polysaccharide bupleuran 2IIc from B. FALCATUM was digested with ENDO-polygalacturonase or degraded with lithium, the resulting oligosaccharides still showed LAL-reactivity. Carboxyl-reduction of acidic polysaccharides increased the reactivity to the beta(1-->3)-glucan-mediated coagulation factor (factor G) but not the factor C. Bupleuran 2IIc and its PG-1 and PG-2 (rhamnogalacturonan II-like region, which contains 2-keto-3-deoxyocuturosonic acid) showed significant mitogenic activities even by using C3H/HeJ mice which are low responder mice to LPS. When the LAL-positive substance was removed from bupleuran 2IIc and its fraction PG-1 by phase separation using Triton X-114, the mitogenic and anti-complementary activities did not change. These results indicated that mitogenic and anti-complementary activity of bioactive pectic polysaccharides from B. FALCATUM were due to the action of pectic polysaccharides but not LPS.
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PMID:Lipopolysaccharide-independent limulus amebocyte lysate activating, mitogenic and anti-complementary activities of pectic polysaccharides from chinese herbs. 1723 43

The application of recombinant (His)(6)-tagged proteins in cell culture assays is associated with problems due to lipopolysaccharide (LPS) contamination. LPS stimulates cells of the immune system, thereby masking antigen-specific activation of T cells. Due to the affinity of LPS for histidine it is associated with difficulties to remove LPS from recombinant (His)(6)-tagged proteins. Here we describe that the Triton X-114 phase separation method can be used to remove LPS from (His)(6)-tagged proteins and that the recombinant proteins retain their biological activity.
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PMID:The biological activity of a recombinantly expressed (His)(6)-tagged peanut allergen (rAra h 1) is unaffected by endotoxin removal. 1837 22

Emulsan has been reported as an emulsion stabilizing amphipathic lipoheteropolysaccharide secreted by the oil-degrading bacterium Acinetobacter venetianus RAG-1. Previously, emulsan was regarded as a single polymer. As a result of developing a new purification process, we have discovered that emulsan is a complex of approximately 80% (w/w) lipopolysaccharide (LPS) and 20% (w/w) high molecular weight exopolysaccharide (EPS). The EPS was purified to 98% (w/w) using tangential flow filtration, Triton X-114 phase extraction, ammonium sulfate precipitation, and hydrophobic interaction chromatography. Several previously reported physical properties of emulsan can be attributed to the LPS fraction, such as charge, fatty acid profile, and solution behavior, while the EPS is responsible for the emulsion stabilization activity. The EPS is believed to be cationic in nature, thus providing an electrostatic binding mechanism for the formation of the emulsan complex.
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PMID:Discovery of the dual polysaccharide composition of emulsan and the isolation of the emulsion stabilizing component. 1854 7


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