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)

The traT protein (TraTp) of the F sex factor is the product of one of the two genes involved in surface exclusion. Several detergents were examined under different conditions in order to determine their ability to solubilize TraTp from membrane vesicles. These experiments showed that TraTp behaved similar to a number of peptidoglycan-associated outer membrane proteins and that it existed in multimeric aggregates within the membrane. However, unlike other major outer membrane proteins, the amount of TraTp incorporated into the membrane was not affected by lipopolysaccharide-deficient mutants, even when mutants totally lacking the neutral sugars in their lipopolysaccharide backbone were used. TraTp wqs also examined by two-dimensional gel electrophoresis, where it ran as a discrete spot with a very basic isoelectric point. By coupling cyanogen bromide-activated dextran onto whole cells and by labeling whole cells with 125I (via lactoperoxidase), it was shown that TraTp was exposed on the cell surface. TraTp in a membrane environment was also insensitive to proteolytic attack by trypsin.
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PMID:Outer membrane of Escherichia coli: properties of the F sex factor traT protein which is involved in surface exclusion. 698 6

The syntheses of oligosaccharide fragments of the O-specific polysaccharide of the lipopolysaccharide of Shigella dysenteriae type 1 are described, including disaccharides methyl O-alpha-D-mannopyranosyl-(1-->2)-alpha-D-galactopyranoside (1), and methyl O-(2-deoxy-2-propionamido-alpha-D-glucopyranosyl)-(1-->3)-alpha-L- rhamnopyranoside (2), trisaccharide methyl O-alpha-D-galactopyranosyl-(1-->3)-O-(2-acetamido-2-deoxy-alpha-D- glucopyranosyl)-(1-->3)-alpha-L-rhamnopyranoside (3), tetrasaccharide methyl O-alpha-L-rhamnopyranosyl-(1-->2)-O-alpha-D-galactopyranosyl-(1-->3)- O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1-->3)-alpha-L-rhamno -pyranoside (4), and pentasaccharide methyl O-alpha-L-rhamnopyranosyl-(1-->3)-O-alpha-L- rhamnopyranosyl-(1-->2)-O-alpha-D-galactopyranosyl- (1-->3)-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-(1-->3)-alpha-L- rhamnopyranoside (5). The following monosaccharide building blocks were used as starting compounds: methyl 6-O-tert-butyldiphenylsilyl-3,4-O-isopropylidene-alpha-D-galact opy ranoside (8), methyl 3,4,6-tri-O-benzyl-2-O-(4-methoxybenzyl)-1-thio-beta-D- galactopyranoside (11), methyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-1-thio-alpha- D-glucopyranoside (16), methyl 2-azido-4,6-O-benzylidene-2-deoxy-1-thio-alpha-D- glucopyranoside (18), methyl 2,4-di-O-benzyl-alpha-L-rhamnopyranoside (21), methyl 2,3,4-tri-O-benzoyl-1-thio-alpha-L-rhamnopyranoside (22), 2,3,4-tri-O-benzoyl-alpha-L-rhamnopyranosyl bromide (23), and methyl 4-O-benzyl-alpha-L-rhamnopyranoside (24). Nuclear magnetic resonance data indicate that oligosaccharides 4 and 5 partially mimic the conformation of the O-specific polysaccharide of S. dys. type 1.
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PMID:Synthesis of di- to penta-saccharides related to the O-specific polysaccharide of Shigella dysenteriae type 1, and their nuclear magnetic resonance study. 752 46

The disaccharides allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-3-deoxy-a lph a-D- manno-2-octulopyranoside (8), allyl O-(3-deoxy-alpha-D-manno-2-octulopyranosyl)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosidonate) (24), and allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->8)-3-deoxy-a lph a-D- manno-2-octulopyranoside (35), and the trisaccharides allyl O-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-3-deoxy-a lph a-D-manno-2-octulopyranoside (13) and allyl O-(3-deoxy-alpha-D-manno-2-octulopyranosyl)-(2-->8)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosylonate)-(2-->4)-(sodium 3-deoxy-alpha-D-manno-2-octulopyranosidonate) (30) were prepared. The ketosidic linkages were formed in good yields and high stereoselectivity by BF3 . Et2O-catalyzed reaction of the per-O-acetylated 3-deoxy-alpha-D-manno-2-octulopyranosyl fluoride derivative (16) with 8-O-SiButMe2 derivatives 19 and 21. Coupling reactions using the Kdo monosaccharide bromide derivative 4 or the alpha-(2-->8)-linked Kdo disaccharide bromide derivatives 9 and 26 were performed under Helferich conditions in MeCN or MeNO2, respectively. The disaccharide halides were prepared in good overall yields starting from the readily available allyl beta-glycoside of Kdo. The deprotected oligosaccharides correspond to the genus-specific lipopolysaccharide epitope of Chlamydia and part structures thereof, containing the carboxyl-reduced Kdo-residues at the distal and proximal position of the Kdo trisaccharide epitope, respectively.
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PMID:Synthesis of carboxyl-reduced analogues related to the Chlamydia-specific Kdo trisaccharide epitope. 752 73

Interleukin (IL)-2, initially discovered for its mitogenic activity on T cells, also acts on monocytes, resulting in the activation of cytokine production, superoxide production, and tumoricidal activity. Because severe brain damage was observed in IL-2-transgenic mice, this cytokine may have some influence(s) on the cells of the CNS. We investigated IL-2 receptor-bearing cells in the CNS and found that activated microglia expressed alpha-chain mRNA and immunoreactive IL-2 receptor beta-chain protein in culture. Although microglia did not express IL-2 receptors under normal culture conditions, they were induced to express these receptors by lipopolysaccharide (LPS) in a time-dependent manner. The IL-2 receptors were found to be functional because the viability and growth activity of LPS-treated microglia, but not untreated controls, increased in response to recombinant mouse IL-2 as determined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay and bromodeoxyuridine uptake experiment, respectively. These effects of recombinant IL-2 were blocked by pretreatment with anti-mouse IL-2 receptor beta-chain antibody. Our findings suggest that activated microglia in the CNS can respond to this T cell-derived factor regulating their growth, which may be an important mechanism of communication between nervous and immune systems in physiological and pathological conditions.
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PMID:Induction of functional interleukin-2 receptor in mouse microglia. 753

The modulating effect of bovine milk casein components and their digests on the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells induced or not induced by mitogens has been studied with a colorimetric assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. All the casein components and their digests tested had little mitogenic effect on the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells. Intact kappa-casein significantly inhibited the proliferative responses of mouse spleen lymphocytes and Peyer's patch cells induced by mitogens such as lipopolysaccharide from Salmonella typhimurium, concanavalin A, phytohaemagglutinin and pokeweed mitogen. In contrast, intact alpha s1-casein and beta-casein had little effect. kappa-Casein had an inhibitory effect after digestion by pancreatin or trypsin, but not after pepsin or chymotrypsin digestion. Both pancreatin and trypsin digests of alpha s1-casein and beta-casein significantly inhibited the proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells induced by mitogens, whereas pepsin and chymotrypsin digests of both caseins were without effect. Moreover, the trypsin digest of each casein component had an inhibitory effect on mouse spleen lymphocyte proliferation in the absence of mitogen. Since trypsin is a major proteinase in pancreatin, the substrate specificity of trypsin seems to be important for the formation of the inhibitory peptides from casein components. These observations suggest that intact kappa-casein and some peptides formed from milk casein components by the action of trypsin may suppress the immune responsiveness of neonates.
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PMID:Inhibition of proliferative responses of mouse spleen lymphocytes and rabbit Peyer's patch cells by bovine milk caseins and their digests. 760 78

A murine IgM monoclonal antibody causing bacterial agglutination was used in an immunoaffinity procedure to purify a serotype 1-specific polysaccharide epitope from Pasteurella haemolytica. The P haemolytica serotype 1-specific antibody was precipitated from peritoneal ascitic fluid, dialyzed, and covalently attached to cyanogen bromide-activated Sepharose 4B beads. Retention of purified antibody activity and coupling efficiency were > 99% when evaluated by ELISA, agglutination testing, and protein determination. Potassium thiocyanate was selected as an eluant on the basis of reversible dissociation of bacterial agglutination and was titrated for the lowest effective concentration. Immunobead activity was observed microscopically by immobilization of encapsulated P haemolytica serotype 1 and its reversible dissociation after elution with 0.4M potassium thiocyanate. Specificity of immobilization was visualized, using P haemolytica serotypes 2 and 5, which were not bound, and by blocking serotype-1 binding with homologous capsular material. Saline-extractable capsular material from P haemolytica serotype 1 was used as an antigen source. After elution of the serotype 1-specific polysaccharide epitope, the product was dialyzed and analyzed, using chemical and immunologic methods. The immunoaffinity product contained no detectable protein and greater than half the original hexosamine content. Using defined monoclonal antibodies in ELISA, titration of the original capsular material and the immunoaffinity product revealed specific retention of lipopolysaccharide, a 10- to 30-kd polysaccharide antigen common to all P haemolytica and P multocida serotypes, and serotype 1-specific capsular polysaccharide, indicating possible epitope sharing among polysaccharide antigens of P haemolytica serotype 1.
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PMID:Purification of a Pasteurella haemolytica serotype 1-specific polysaccharide epitope by use of monoclonal antibody immunoaffinity. 768 55

We examined whether inhibitors of the arachidonic acid cascade inhibited nitric oxide (NO) production, as measured by nitrite concentration, either in macrophages or by their cytosolic fractions. Nitrite production by peritoneal macrophages from mice receiving OK-432 treatment was significantly inhibited by phospholipase A2 inhibitors [dexamethasone and 4-bromophenacyl bromide (4-BPB)], lipoxygenase inhibitors [nordihydroguaiaretic acid (NDGA) and ketoconazole] and a glutathione S-transferase (leukotrienes LTA4-LTC4) inhibitor (ethacrynic acid). However, caffeic acid and esculetin, inhibitors of 5- and 12-lipoxygenase respectively, were not inhibitory. On the other hand, indomethacin, a cyclooxygenase inhibitor, slightly inhibited whereas another inhibitor, ibuprofen, did not. Inhibition of the nitrite production by dexamethasone, 4-BPB, NDGA and ethacrynic acid was also demonstrated when the macrophages were restimulated ex vivo with OK-432 or with lipopolysaccharide. The inhibitory activity of dexamethasone, NDGA and ethacrynic acid was significantly reduced by ex vivo restimulation with OK-432, whereas that of 4-BPB was hardly affected. Furthermore, the inhibitory activity of dexamethasone, NDGA and ethacrynic acid was much higher when the macrophages were continuously exposed to the agents than when they were pulsed. Meanwhile, inhibition by 4-BPB was almost the same with either treatment. In addition, the inhibitory activity of these agents was not blocked with L-arginine, a substrate of NO synthases, or with arachidonate metabolites (LTB4, LTC4 and LTE4). Ethacrynic acid and 4-BPB, but not dexamethasone and NDGA, also inhibited nitrite production by the cytosolic fractions from OK-432-restimulated peritoneal macrophages, and the inhibitory activity of 4-BPB was superior to that of ethacrynic acid. These agents, however, did not inhibit nitrite production from sodium nitroprusside, a spontaneous NO-releasing compound. These results indicate that dexamethasone, 4-BPB, NDGA and ethacrynic acid inhibited the production of NO by macrophages through at least two different mechanisms: one was inhibited by dexamethasone, NDGA and ethacrynic acid and the other by 4-BPB. Furthermore, 4-BPB and ethacrynic acid directly inhibited the activity of the NO synthase in macrophages, suggesting that the agents work by binding to the active site(s) of the enzyme.
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PMID:Inhibition of macrophage nitric oxide production by arachidonate-cascade inhibitors. 769 96

Plasma procoagulant activity inducing factor (PIF) is a spontaneously occurring, potent inducer of macrophage procoagulant activity (PCA) in the male BXSB murine model of systemic lupus erythematosus. The physical characteristics of PCA induction by PIF, aggregated mouse IgG, and lipopolysaccharide (LPS) were compared. Both aggregated IgG and PIF-induced PCA were heat, acid and alkali sensitive. In contrast, LPS-induced PCA was heat resistant and only partially acid and alkali sensitive. Plasma containing PIF was fractionated on Sephacryl S-300. The PIF activity localized to the first protein peak, molecular weight 400,000 to 900,000 daltons. Analysis of peak 1 by an enzyme-linked immunosorbent assay showed the presence of IgM, IgA and IgG. This was confirmed by Western blot analysis using 125I-labelled goat anti-mouse IgM, IgA and IgG probes. The concentration of PIF increased with Sephacryl S-300 chromatography and was reduced by removal of IgG, but not IgA or IgM by affinity chromatography. Peak 1 did not contain DNA as revealed by ethidium bromide staining. Thus, IgG from the plasma of BXSB mice, a strain which develops lupus nephritis, stimulates macrophages to express PCA, accounting for PCA induction in the BXSB model of murine lupus.
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PMID:Characterization of the procoagulant-inducing factor derived from the plasma of BXSB mice. 773 36

During the course of gene therapy experiments in rodents, using intramuscular injections of plasmid DNA derived from Escherichia coli, we noted dose-related toxicity. This observation prompted a search for possible contaminants of DNA samples. We used the highly specific and sensitive limulus amoebocyte lysate assay (LAL), to monitor endotoxin bioactivity in DNA samples, and found plasmid DNA derived from standard E. coli bacterial strains, using traditional DNA isolation protocols, to be heavily contaminated with endotoxin, or lipopolysaccharide (LPA). Standard DNA isolation procedures resulted in the copurification of up to 500 micrograms/ml of LPS. LPS is a potent inducer of cytokines and other inflammatory mediators, and may complicate the use of naked DNA in gene therapy. The copurification of endotoxin with plasmid DNA also has important implications for in vitro transfection studies and microinjection of DNA into embryos. A simple and efficient protocol to reduce LPS contamination of plasmid DNA was developed. The conversion of intact bacteria to spheroplasts prior to the isolation of plasmid DNA, incubation with lysozyme, treatment with the detergent n-octyl-beta-D-thioglucopyranoside (OSPG) and polymyxin-B (PMB) chromatography, allowed the isolation of plasmid DNA containing less than 50 ng/ml LPS. This represents a 10,000-fold reduction in LPS contamination, compared to conventional methods of plasmid DNA purification, avoids potentially toxic reagents such as ethidium bromide, and produces a higher yield of plasmid DNA.
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PMID:Bacterial lipopolysaccharide copurifies with plasmid DNA: implications for animal models and human gene therapy. 777 15

A blastogenesis microassay employing 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) was adapted to measure blastogenic responses of lymphocytes from the chicken's head-associated lymphoid tissues (i.e., the harderian gland and conjunctiva-associated lymphoid tissue) to T- and B-cell mitogens. Lymphocytes isolated from peripheral blood, spleen, and the harderian gland had highly significant (P < 0.01) responses to T- and B-cell mitogens compared with control lymphocytes cultured without mitogens. Cultured lymphocytes obtained from the harderian gland had highly significant mitogenic responses to the T-cell mitogen concanavalin A (25 to 100 micrograms/ml) and to the B-cell mitogen Salmonella typhimurium lipopolysaccharide (1.25 to 5.0 micrograms/ml) compared with the control lymphocytes. Mitogenic responses of cultured lymphocytes obtained from the conjunctiva-associated lymphoid tissue could not be measured within the given parameters of the blastogenesis microassay. This was primarily due to the low yield of lymphocytes, which proved to be a limiting factor. The ability of the MTT blastogenesis microassay to detect blastogenic responses of the harderian gland to mitogens may be indicative of its usefulness for measuring cell-mediated immunity responses to other antigens.
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PMID:Mitogenic responses of the head-associated lymphoid tissues of the chicken. 779 67


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