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)

The antiphagocytic antigen (antigen [a]) comprising the microcapsule of a strain of Campylobacter fetus subsp. intestinalis has been purified from culture supernatants by ammonium sulfate fractionation and free-flow electrophoresis. Antigen [a] is a glycoprotein containing about 4% carbohydrate consisting of hexose, pentose, and methylpentose. The composition of the protein was typical of bacterial extramural structural proteins in its low content of basic, aromatic, and sulfur-containing amino acids. The protein had a high content of aspartic acid, threonine, glycine, and alanine. Antigen [a] had an Rf of 0.33 on polyacrylamide gel electrophoresis and a molecular weight calculated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis of approximately 98,000. In contrast to its free form in culture supernatants, antigen [a] in vesicles derived from sheared cells appeared to exist in a complex with lipopolysaccharide. This complex could be dissociated by ethylenediaminetetraacetic acid or by ethylenediaminetetraacetic acid plus Triton X-100. A mutant strain that lacked a microcapsule, when incubated with soluble antigen [a] in a calcium medium, became agglutinable by monospecific [a] antiserum and showed an additional structural layer similar in appearance to the microcapsule on its cell wall. Points of similarity are emphasized between antigen [a] of C. fetus and the outer structural protein of the taxonomically related Spirillum serpens.
 ...
PMID:Microcapsule of Campylobacter fetus: chemical and physical characterization. 73 Mar 87

Protein phosphorylation is central to multiple regulatory processes in cells. Tumor necrosis factor (TNF), a cytokine synthesized by macrophages, effects polymorphonuclear leukocyte (neutrophil) chemotaxis, induces superoxide anion generation, and mediates neutrophil adhesion to endothelial cells. Although protein phosphorylation is almost certainly involved in many TNF-mediated neutrophil functions, little is known about TNF's impact on neutrophil protein phosphorylation. Therefore, we studied human recombinant TNF-alpha-induced protein phosphorylation in human neutrophils. Neutrophils were preincubated with 32PO(4)2- and treated with a variety of stimulatory agents. One- and two-dimensional polyacrylamide gel electrophoresis was used to analyze phosphorylated proteins. Phosphoaminoacids were identified by two-dimensional thin layer chromatography electrophoresis. The findings were as follows: (1) TNF induces the phosphorylation of two 16-kD proteins (pI = 5.9 and 6.1) by 5- to 6-fold, and a 57-kD protein (pI = 5.8) by 3- to 4-fold compared with untreated neutrophils; (2) these proteins are phosphorylated as early as 15 min after stimulation with TNF, and phosphorylation is induced by concentrations of TNF as low as 1 ng/ml (10 U/ml); (3) TNF induces the phosphorylation of proteins at either serine or threonine residues and not at tyrosine; (4) TNF-stimulated neutrophils show a unique pattern of protein phosphorylation when compared to neutrophils treated with formylmethionylleucylphenylalanine; (5) lipopolysaccharide does not induce protein phosphorylation in neutrophils; (6) a 16-kD protein is phosphorylated in response to TNF in neutrophils but not in mononuclear cells; and (7) protein kinase inhibitors appear to have no effect on TNF-induced protein phosphorylation. Thus, the mechanism of action of TNF on neutrophils may involve protein phosphorylation.
 ...
PMID:Tumor necrosis factor-induced protein phosphorylation in human neutrophils. 191 Aug 14

Chemical analysis of the lipopolysaccharide from Rhodopseudomonas sphaeroides ATCC 17023, isolated by the phenol-chloroform-petroleum ether method, revealed the presence of glucuronic acid, 2-keto-3-deoxyoctonate, threonine, and phosphorus in the polysaccharide moiety. The lipid A component contained glucosamine, glucosamine phosphate, amide-bound 3-oxotetradecanoic acid and 3-hydroxytetradecanoic acid, and ester-bound 3-hydroxydecanoic acid and 7-tetradecenoic acid. Structural similarity of the lipid A from R. sphaeroides ATCC 17023 to enterobacterial lipid A is indicated by the existence of a serological cross-reaction occurring between the lipid A from R. sphaeroides ATCC 17023 and that from Salmonella minnesota R595. The lipopolysaccharide and lipid A of R. sphaeroides, however, were found to be neither toxic in mice nor pyrogenic in rabbits.
 ...
PMID:Nontoxic lipopolysaccharide from Rhodopseudomonas sphaeroides ATCC 17023. 660 1

Endotoxin-associated protein (EP) from Salmonella typhi activated murine resident peritoneal macrophages to produce prostaglandin E2 (PGE2). Cells from both endotoxin nonresponder (C3H/HeJ) and the endotoxin responder (C3H/OuJ) mouse strains were activated by EP. This EP-induced prostaglandin E2 production was blocked by the protein kinase C (PKC) inhibitor H-7 as well as the tyrosine kinase inhibitor genistein, suggesting the involvement of both serine and threonine phosphorylation and tyrosine phosphorylation pathways in the activation of resident peritoneal macrophages by EP. Immunoblot analysis using antiphosphoserine and antiphosphothreonine antibodies showed that EP induced the serine and threonine phosphorylation of a 14-kDa protein (p14). This phosphorylation was not induced by phorbol myristic acid or by lipopolysaccharide endotoxin. Inhibitors of PKC, PKA, and PKG did not block the phosphorylation of p14. However, the tyrosine kinase inhibitor piceatannol blocked p14 serine and threonine phosphorylation, suggesting that this phosphorylation is dependent upon and preceded by a tyrosine phosphorylation step.
 ...
PMID:Induction of serine and threonine protein phosphorylation by endotoxin-associated protein in murine resident peritoneal macrophages. 752 47

Phospholipid-containing antigens of malaria parasites stimulate macrophages to secrete tumour necrosis factor (TNF), induce hypoglycaemia and are toxic to mice. This TNF induction is inhibited by antisera made against the antigens, the inhibitory activity of which can be removed specifically by adsorption to phosphatidylinositol (PI) liposomes. Although the same was true of antisera made against PI, the inhibitory activity of antisera made against some other phospholipids appeared to be directed against a common determinant, probably the phosphate ester head group. We have shown previously that the activity of all the antisera was associated mainly with IgM and was not boosted by repeated injections of the antigens. To try and induce a secondary response against the parasite antigens using non-toxic molecules, mice were immunized with various phosphorylated compounds coupled to keyhole limpet haemocyanin (KLH). Three injections of PI-KLH or of phosphatidylserine (PS) coupled to KLH induced significantly higher titres of inhibitory antibody than one; furthermore, the inhibitory activity was mainly in the IgG fraction. The antisera did not inhibit TNF induction by lipopolysaccharide (LPS) or lipoteichoic acid. However, antisera against PS-KLH, though not PI-KLH, inhibited the induction of TNF by the phospholipid, platelet-activating factor (PAF). These antisera, and antisera from mice immunized with phospho-threonine or galactosamine-1-phosphate conjugated to KLH, contained inhibitory antibodies of differing specificities. Mice immunized with PI-KLH, PS-KLH or phospho-threonine-KLH did not develop hypoglycaemia when challenged with the parasite toxic antigens. These results indicate that the antigenicity of non-toxic analogues can be dramatically enhanced by coupling to a protein carrier.
 ...
PMID:Phospholipids coupled to a carrier induce IgG antibody that blocks tumour necrosis factor induction by toxic malaria antigens. 850 34

Macrophage activation by lipopolysaccharide (LPS) results in the translational activation of tumor necrosis factor (TNF) mRNA. The initial phase of macrophage activation is followed by a refractory state called LPS tolerance characterized by an impaired TNF production in response to a secondary LPS challenge. LPS-tolerant macrophages contain high amounts of TNF mRNA, suggesting a translational regulation of TNF biosynthesis. The induction of LPS tolerance was studied in RAW 264.7 macrophages stably transfected with a chloramphenicol acetyl-transferase (CAT) reporter gene construct driven by a constitutive cytomegalovirus promoter and containing the 3' untranslated region of the murine TNF gene. We found that primary stimulation of transfected cells by LPS (1 ng/ml, 12 hr) resulted in a marked suppression (80%) of CAT accumulation in response to a secondary LPS challenge (1 microgram/ml, 6 hr). In contrast, the accumulation of CAT mRNA was not influenced by LPS tolerance. Using the same CAT reporter, we observed that the serine/threonine phosphatases 1 and 2A inhibitor okadaic acid induced TNF mRNA translation and that this activation was not inhibited by LPS-tolerance. In conclusion, these data indicate that deficient production of TNF in LPS-tolerant macrophages in response to a second LPS challenge is characterized by a defective translation of TNF mRNA. However, this hyporesponsiveness to LPS is specific, since translation of TNF mRNA induced by okadaic acid is not inhibited in LPS-tolerant macrophages.
 ...
PMID:Defective translation of tumor necrosis factor mRNA in lipopolysaccharide-tolerant macrophages. 873 92

Porphyromonas gingivalis 381 lipopolysaccharide (LPS) definitely exhibited mitogenic activity in purified B-cells, separated from spleens of LPS-responsive C3H/HeN mice and LPS-non-responsive C3H/HeJ mice by using a magnetic cell sorting system. The mitogenic activity induced by P. gingivalis LPS was incompletely inhibited by polymyxin B. P. gingivalis LPS also induced a higher production of interleukin-6 (IL-6) in splenic B-cells of C3H/HeN mice as compared with Escherichia coli LPS. Furthermore, P. gingivalis LPS, but not E. coli LPS, induced definite IL-6 production in C3H/HeJ mice. P. gingivalis LPS increased tyrosine, serine/threonine phosphorylation of proteins with various major induced bands in splenic B-cells of both C3H/HeN and C3H/HeJ mice. Additionally, radioiodinated P. gingivalis LPS, similarly to E. coli LPS, bound to a 73-kDa protein on C3H/HeJ as well as C3H/HeN B-cells. Thus P. gingivalis LPS may activate B-cells of C3H/HeJ as well as C3H/HeN mice via the LPS-specific binding protein on the cells.
 ...
PMID:Splenic B-cell activation in lipopolysaccharide-non-responsive C3H/HeJ mice by lipopolysaccharide of Porphyromonas gingivalis. 884 20

The objective of this study was to investigate the effects of nutrient density and dietary energy source on performance and immune function of weanling pigs that were either challenged or not challenged with Escherichia coli lipopolysaccharide (LPS). A basal diet was formulated to contain 14 g CP/MJ DE and 7 g lysine/100 g CP. Sulfur amino acids, threonine and tryptophan were kept constant relative to lysine. Experimental diets were mixed using 70 parts basal diet and either 30 parts starch or an isocaloric amount (14 parts) of lard. Diets were fed either for ad libitum intake or on a pair-feeding basis to evaluate effects of diet nutrient density or source of energy, respectively. On d 9 and 25, pigs were challenged i.m. with either 1 mL of a LPS solution or a control solution. Lymphocyte blastogenesis was measured 2 d after the LPS administration and antibody response to sheep red blood cells (SRBC) or ovalbumin was determined 3 d after challenge. No interactive effects on performance were observed between LPS challenge and energy density or source of energy (P > .10). Injection of LPS tended to reduce feed intake and daily gain (P < .10), but not efficiency of feed or energy utilization. Addition of fat to the diets improved feed efficiency and efficiency of energy utilization for gain (P < .05). No consistent effects of LPS challenge, energy density, or source of energy were observed for lymphocyte blastogenesis. Antibody response to ovalbumin, but not to SRBC, was decreased by fat (P < .05). Results indicate that increasing energy density of the diet did not alter the performance depression due to LPS challenge. Addition of fat to the diet improved feed efficiency and efficiency of energy conversion but may depress the humoral immune response. Effects of fat on the immune response may depend on the immune status of the pig.
 ...
PMID:Effects of immune challenge, dietary energy density, and source of energy on performance and immunity in weanling pigs. 890 12

1. Microglial cells represent the first line of defence in the brain against infection and damage. However, under conditions of chronic inflammation and neurodegeneration, excessive activation of microglia can contribute to the neurodegenerative process by releasing a cornucopia of potentially cytotoxic substances including the cytotoxic free radical nitric oxide (NO). Although the cell signalling events implicated in NO formation in peripheral macrophages are well defined, events occurring in the phenotypically homologous cerebral microglial cell are not yet fully characterized. 2. In the present study, a cloned murine microglial cell line (N9), stimulated with combined lipopolysaccharide/interferon-gamma (LPS/IFN) incubation, was shown to produce a significant increase in NO formation, as measured by medium nitrite levels, during 8-72 h exposure. 3. LPS/IFN-stimulated NO production was partially inhibited with the nitric oxide synthase (NOS) competitive antagonists; N(omega)-nitro-L-arginine methyl ester and N(omega)-nitro-L-arginine. The ability of the selective inducible (iNOS) inhibitor, aminoguanidine, but not the selective 'neuronal-type' constitutive (cNOS) inhibitor 7-nitroindazole, to inhibit NO production suggested a primary role of iNOS in this response and was confirmed by immunolabelling of activated cells with a specific iNOS antibody. 4. A series of tyrosine kinase inhibitors, herbimycin A, genestein, tyrphostins, AG-126, AG-556 and the tyrosine phosphatase inhibitors, sodium orthovanadate and phenylarsine oxide, significantly attenuated LPS/IFN-mediated NO production. The serine/threonine kinase inhibitors, staursporine (protein kinase C), H-9 (cyclic GMP/cyclic AMP-dependent kinase) or serine/threonine phosphatase inhibitors, cyclosporin A (phosphatase 2B) and okadaic acid (phosphatase 1/2A), reduced NO formation by an apparent cytostatic mechanism, as determined by cellular reduction of 3-(4,5-dimethylthiazol-2-yi)-2,5-diphenyl-tetrazolium bromide (MTT). 5. The present results suggest that the co-ordinated activation of protein tyrosine kinases/phosphatases, and proximal signalling events implicating the interplay between serine-threonine kinases/phosphatases, is intricately linked with inflammatory mediated mechanisms of iNOS activation in microglial cells by regulating the activation of the transcription factor NFkappaB.
 ...
PMID:Suppression of nitric oxide formation by tyrosine kinase inhibitors in murine N9 microglia. 953 16

Exposure of animals to infectious agents induces immune responses that result in reductions in food consumption and weight gain. The effect of these changes on amino acid requirements and utilization remains unclear. Three assays were conducted with young chicks with Escherichia coli lipopolysaccharide (LPS) used to stimulate the immune system. An initial study was conducted to evaluate the effects of LPS on animal performance. In a daily or alternate day injection regimen for 9 d, chicks were given intraperitoneal injections of sterile saline containing 0, 100 or 400 microgram LPS. Administration of 100 or 400 microgram LPS daily, or every other day, decreased both weight gain and food consumption. In two subsequent growth assays, chicks were fed graded levels of lysine or threonine and injected with either 0 or 400 microgram LPS every other day to evaluate the effect of LPS administration on the efficiency of amino acid utilization. At the three lowest amino acid doses, whole-body protein accretion was a linear function of supplemental lysine or threonine intake, and slopes of the accretion curves were not altered by LPS administration. The dietary lysine concentration required to maximize protein accretion was unaffected by LPS, but the absolute lysine intake required to maximize chick performance was lower in LPS-injected chicks than in saline-injected chicks. These results show that LPS administration reduces weight gain, food intake, efficiency of food utilization and the absolute quantity of lysine required to maximize these criteria. However, LPS administration does not affect the efficiency of amino acid utilization, nor does it affect the concentration of dietary lysine required to maximize performance.
 ...
PMID:Lipopolysaccharide-induced reductions in food intake do not decrease the efficiency of lysine and threonine utilization for protein accretion in chickens. 977 47


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