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)

C3H/HeN mice administered BCG followed by lipopolysaccharide 14 days later released into their serum a cytotoxic factor for tumor cells and a factor that restored the anti-SRBC plaque-forming cell response of nude mouse spleen cells (helper activity). Gel filtration of serum containing the cytotoxic and the helper activities indicated that both factors exhibited an apparent m.w. of 125,000 to 150,000. The helper activity was also found at lower m.w. (60,000 and 13,000) suggesting the possibility that this factor existed in aggregated forms. Gel filtration of ammonium sulfate (40 to 60% saturation) precipitated serum in a high ionic strength buffer (1.6 M NaCl) resulted in shifts in the apparent m.w. of both factors. The cytotoxic factor now exhibited a m.w. of 55,000. The helper activity eluted with an apparent m.w. of 13,000, and thus was clearly separated from the cytotoxic factor. The helper activity was further shown to co-elute with macrophage-derived lymphocyte activating factor (LAF). This as well as other data represent the first demonstration of in vivo produced LAF.
 ...
PMID:Separation of a serum-derived tumoricidal factor from a helper factor for plaque-forming cells. 698 7

A naturally occurring hemagglutinin was detected in the serum of the hermit crab Diogenes affinis, and its erythrocyte (RBC) binding activities, physicochemical properties, and carbohydrate binding specificity were characterized. Both the hemagglutination profile and the pattern of cross-reactivity of the serum with different RBC types in cross-adsorption tests suggested a strong affinity of the serum agglutinin for rat RBC. Further analysis revealed that the agglutinin was specifically dependent on Ca2+ for its hemagglutinating activity and reversibly sensitive to EDTA. The activity was found to be stable between pH 6.0 and 7.5, heat-labile, and completely precipitable by ammonium sulphate or TCA, suggesting the proteinaceous nature of the serum agglutinin. In hemagglutination-inhibition assays, the serum agglutinin of D. affinis showed a distinct and unique specificity for acetyl group-containing carbohydrates and glycoprotein. Furthermore, the hemagglutinating activity of the serum agglutinin was also inhibited by lipopolysaccharide from Salmonella abortus equi, which might indicate a significant role of humoral agglutinin in the immune response of crustaceans against bacterial infection.
 ...
PMID:A lipopolysaccharide-binding hemagglutinin with specificity for acetylated aminosugars in the serum of the hermit crab Diogenes affinis (Henderson). 780 93

The Escherichia coli K-12 NAD-dependent nucleotide-diphosphosugar epimerase, ADP-L-glycero-D-mannoheptose 6-epimerase, catalyzes the conversion of ADP-D-glycero-D-mannoheptose to ADP-L-glycero-D-mannoheptose. ADP-L-glycero-D-mannoheptose is a key intermediate of lipopolysaccharide inner core biosynthesis in several genera of Gram-negative bacteria. Sedimentation equilibrium and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified epimerase revealed that the native enzyme has a molecular mass of 240 kDa and a subunit molecular weight of 37,000 +/- 3,000. Lectin binding studies of the purified epimerase indicated that the protein is glycosylated. There was 1 mol of tightly bound NAD+ per enzyme subunit. Variable but small fractions of purified preparations of epimerase are highly fluorescent and contain NADH. The native enzyme can be resolved into apoenzyme and NAD+ by acidic ammonium sulfate precipitation. The catalytic activity can be reconstituted with the addition of NAD+ to the apoenzyme. Optimum pH range for enzyme activity is broad, between 5.5 and 9.5. It exhibits a temperature optimum at 42 degrees C. The Km and Vmax for the substrate is 0.1 mM and 46 mumol 30 min-1 mg-1, respectively. The native enzyme displays UV and fluorescence spectra that are consistent with the presence of enzyme bound NAD+. CD spectra of the holoepimerase indicate 11% alpha-helical and 36% beta-sheet structures.
 ...
PMID:Purification and properties of the Escherichia coli K-12 NAD-dependent nucleotide diphosphosugar epimerase, ADP-L-glycero-D-mannoheptose 6-epimerase. 792 99

Helicobacter pylori is now accepted as the major cause of chronic gastritis. The initial response to infection is acute neutrophilic gastritis, which progresses to active chronic gastritis in most people. To confirm the pathogenic role of H. pylori, both the individual histological features of chronic gastritis and its topographical patterns must be shown to be caused by the infection. Surface epithelial degeneration is a probable result of direct tissue injury by bacterial products. Candidates are ammonia or ammonium products, cytotoxins, phospholipases and pro-inflammatory products such as lipopolysaccharide and platelet-activating factor. Neutrophil polymorph and chronic inflammatory cell infiltration are consequences of the mucosal immune response to bacterial antigens. Complement products and interleukin (IL)-8 are polymorph chemotaxins, and monocyte processing of antigens, followed by T helper cell and B lymphocyte responses, explain the presence of these cells in the mucosa. Atrophy may be a consequence of autodestructive products of neutrophil and monocyte activation, such as reactive oxygen metabolites and proteases. Intestinal metaplasia is most probably an adaptive response, possibly to H. pylori infection, exacerbated by other injurious agents such as bile reflux and dietary irritants. Pangastritis is the usual outcome after H. pylori infection. This is followed by multifocal atrophy and intestinal metaplasia. The latter changes weaken mucosal defences further and peptic ulceration may ensue. Patients with an increased parietal cell mass who become infected with H. pylori will exhibit antral restriction of the gastritis because the high acid output protects the corpus mucosa from bacterial adhesion and the inflammatory consequences. Such patients also have acid-induced gastric metaplasia in the proximal duodenum.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Pathophysiology of Helicobacter pylori infection. 804 28

Rheumatoid arthritis synovial fluid (RA-SF) contains a novel biological activity, which selectively induces IgG2b antibody production in lipopolysaccharide (LPS)-activated mouse spleen cells in vitro and in vivo. Our previous studies have shown that this activity is not functionally identical to other well-known cytokines and interleukins. In this study we demonstrate the partial purification and biochemical characterization of the IgG2b inducing activity in RA-SF. Biochemical characterization revealed that the IgG2b inducing activity in RA-SF has the following properties: it is a protein, sensitive to pH > 11 and < 4, which is precipitated by 50% of saturated ammonium sulphate and has a molecular weight of 50-70 kDa; it binds to Cibacron-blue and heparin and its activity is not mediated by immunoglobulins or immune complexes, which are present in RA-SF. Biochemical characteristics of the IgG2b inducing activity also differ from other cytokines and interleukins. The term IgG2b inducing factor is proposed for this novel activity.
 ...
PMID:Partial biochemical characterization and purification of IgG2b inducing factor as a new cytokine from synovial fluid of patients with rheumatoid arthritis. 846 25

Treatment of cultured mouse macrophages with either of two different vanadium compounds was shown to affect the production/release of two major immunoregulatory cytokines. The pentavalent vanadium compound ammonium metavanadate was shown previously to disrupt cell-mediated immunity at the earliest stages of an in vivo anti-Listerial response, in that mice treated with vanadium displayed decreased accessory cell recruitment and numbers of activated macrophages at infection sites. To determine whether these effects were due to vanadium-induced alterations in the production of biologically-active mediators, mouse macrophage-like WEHI-3 cells were treated in vitro with ammonium metavanadate or vanadium pentoxide prior to stimulation with lipopolysaccharide endotoxin (LPS). After stimulation, monokine (tumor necrosis factor-alpha and interleukin-1) and prostaglandin E2 (PGE2) activities were assessed. Both vanadium compounds decreased recovered monokine activities; measured TNF alpha concentrations were also reduced. Spontaneous release of the IL-1/TNF-regulating prostanoid PGE2 was significantly increased by the highest concentration of vanadate tested, although LPS-stimulated PGE2 production was unaffected by either compound. These results indicate that, in vitro, pentavalent vanadium can interfere with immunoregulatory mediators critical for maintaining host immunocompetence.
 ...
PMID:Immunotoxicity of in vitro vanadium exposures: effects on interleukin-1, tumor necrosis factor-alpha, and prostaglandin E2 production by WEHI-3 macrophages. 850 53

We investigated a possible mechanism by which immunization against core and lipid A determinants of lipopolysaccharide reduced clinical cases of mastitis and symptoms commonly associated with heterologous Gram-negative IMI. The IgG fraction of sera from cows immunized with either Escherichia coli J5 bacterin, E. coli J5 lipopolysaccharide conjugate vaccine, or unimmunized controls was purified by precipitation with caprylic acid and ammonium sulfate. The degree of IgG crossreactivity with Gram-negative bacteria that were isolated from clinical quarters was greater than that with Gram-positive isolates of Staphylococcus aureus. The highest magnitude of crossreactivity was against smooth strain E. coli isolates, followed by heterologous species of Enterobacter, Serratia, and Klebsiella isolates. Serum IgG from cows immunized with conjugate was highly crossreactive to E. coli J5, E. coli O111:B4, Serratia marcescens, Klebsiella pneumoniae, and Salmonella typhimurium lipopolysaccharides. The magnitude of antibody crossreactivity with lipopolysaccharides coincided with the ability of IgG to suppress the mitogenic effect of lipopolysaccharides on bovine lymphocytes.
 ...
PMID:Antigenic crossreactivity and lipopolysaccharide neutralization properties of bovine immunoglobulin G. 867 57

Ammonium acetate decreased in a concentration-dependent manner the phagocytic uptake of mannosylated latex microspheres and of yeast by immortalized human microglia (CHME-5) and astroglioma (GL-15) cells. In both cell lines ammonium acetate affected also the secretion of certain cytokines. The most conspicuous effects were the following: in both cell lines ammonium acetate enhanced greatly the secretion of tumor necrosis factor-alpha in the absence of any other stimulus. in the human microglia cells ammonia decreased the constitutive secretion of interleukin-6, but it enhanced the stimulated (interleukin-1 alpha, tumor necrosis factor-alpha, gamma-interferon and gamma-interferon + tumor necrosis factor-alpha) secretion of interleukin-8. In the astroglioma cell line, the stimulated release of tumor necrosis factor-alpha, interleukin-6 and interleukin-8 was diminished by ammonium acetate. The magnitude of the ammonia-effect depended on the stimulating agent (lipopolysaccharide, interleukin-1 alpha, tumor necrosis factor-alpha, gamma-interferon). The results are discussed with regard to their potential importance in the pathogenesis of human diseases with elevated blood and brain ammonia concentrations.
 ...
PMID:Effect of ammonia on endocytosis and cytokine production by immortalized human microglia and astroglia cells. 884 42

Haemolytic activity was identified in cell-free haemolymph from larval and imago stages of Leptinotarsa decemlineata. The haemolytically active fraction of the haemolymph was active against human, sheep, bull, toad and mouse erythrocytes. There was no haemolysis in the presence of 0.001 M EDTA and 0.5% glutathione. The titre of haemolytic activity did not increase after injury or vaccination of the larvae with Microccocus lysodeikticus. Haemolysin, a heat-labile protein was partially purified by ammonium sulphate precipitation, gel filtration, and ion-exchange separation. SDS PAGE, electrophoresis and immunoblotting showed that the active factor was a protein with a molecular weight of approximately 55 kD. It was not bactericidal for various micro-organisms but the antibacterial activity of the lysozyme increased in the presence of haemolysin only when M. lysodeikticus were used as target cells. Spherulocytes synthesized and released the haemolytic protein in vitro. The haemolytic activity increased in the presence of lipopolysaccharide from Escherichia coli and Ca++ ions. The physiological role of the haemolysin is as yet unknown.
 ...
PMID:Cell-mediated haemolytic activity of haemolymph from the Colorado potato beetle (Leptinotarsa decemlineata Say.) 895 58

Previous studies with 31 strains of Serratia marcescens, including 28 reference O-serotype strains, have indicated that 19 of them have an acidic polysaccharide which copurifies with lipopolysaccharide during phenol-water extraction. Polysaccharide in crude extracts from 18 of the 19 strains was precipitated with Cetavlon (hexadecyltrimethyl ammonium bromide), and capsules were demonstrated around these 18 strains by Indian ink exclusion zones. Capsule-antibody binding by the Quellung reaction suggested that the acidic polysaccharide formed the capsule around the bacterial cells. Anticapsular (anti-K) antibody was detected in reference O antisera which had been prepared against boiled whole cells. Cross-titration and absorption studies revealed 14 different K antigens among these strains.
 ...
PMID:Identification of capsular antigens in Serratia marcescens. 896 81


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>