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 isolation and characterization of two mutants of Escherichia coli K12 with an altered outer membrane protein c is described. The first mutant, strain CE1151, was isolated as a bacteriophage Me1 resistant strain which contains normal levels of protein c. Mutant cells adsorbed the phage with a strongly decreased rate. Complexes of purified nonheat modified wild type protein c and wild type lipopolysaccharide inactivated phage Me1, indicating that these components are required for receptor activity for phage Me1. When wild type protein c was replaced by protein c of strain CE1151, the receptor-complex was far less active, showing that protein c of strain CE1151 is altered. The second mutant produces a protein c with a decreased electrophoretic mobility, designated as protein c. An altered apparent molecular weight was also observed for one or more fragments obtained after fragmentation of the mutant protein with cyanogen bromide, trypsin and chymotrypsin. Alteration of protein c was not accompanied by a detectable alteration in protein b or its fragments. Both mutations are located at minute 48 of the Escherichia coli K12 linkage map. The results strongly suggest that meoA is the structural gene for protein c.
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PMID:meoA is the structural gene for outer membrane protein c of Escherichia coli K12. 37 4

Spleen cells of C57B1/6J mice immunized with complete Freund's adjuvant produced macrophage migration inhibitory factor (MIF) when incubated in vitro with tuberculin purified protein derivative (PPD). For optimal MIF production spleen cells were cultured for 48 h in a serum-free medium, at a concentration of 2 x 10(7) cells/ml. MIF was assayed in a xenogenic system, using oil-induced guinea pig peritoneal exudate cells as targets. MIF synthesis could also be induced by pulsing spleen cells for 2 h with concanavalin A, phytohemagglutinin, pokeweed mitogen or lipopolysaccharide, followed by culture in plain medium. No MIF secretion was induced by incubation of spleen cells with anti-theta or rabbit anti-mouse IgG sera. Cells producing MIF in response to PPD were characterized as B cells by virtue of being insensitive to anti-theta serum and complement, by being retained on nylon wool, glass bead and anti-Ig colums and by the presence of Fc receptors. PPD-stimulated T cells did not produce MIF. PPD-induced mouse spleen cell MIF demonstrated a moderate loss of activity by heating at 56 and 80 degrees C and was completely inactivated after digestion with chymotrypsin. By fractionation on Sephadex G-200, migration inhibitory activity was recovered in a molecular range of 100,000-12,400 daltons.
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PMID:Antigen and mitogen induced production of macrophage migration inhibitory factor in the mouse. 37 63

1. alpha-1-Antiproteinase (also called alpha-1-antitrypsin or alpha-1-proteinase inhibitor) with a molecular mass of 60 kDa was purified to apparent homogeneity from hamster plasma. 2. It inhibited elastase, chymotrypsin and trypsin, but did not significantly affect pancreatic kallikrein, plasma kallikrein or plasmin. 3. It has the same N-terminal heptapeptide sequence as that of rat alpha-1-antiproteinase. 4. Its plasma level decreased after injection of bacterial lipopolysaccharide.
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PMID:Purification, characterization, and acute phase response of plasma alpha-1-antiproteinase in the hamster, Mesacricetus auratus. 172 45

Bacterial cell wall peptidoglycan (PGN) and lipopolysaccharide (LPS), which are both macrophage activators and polyclonal B cell mitogens, were shown to bind to the same dominant 70-kDa 6.5 pI protein on the surface of mouse B lymphocytes. This conclusion was supported by the following results: (a) the PGN- and LPS-binding proteins co-migrated following photoaffinity cross-linking and two-dimensional polyacrylamide gel electrophoresis; (b) cross-linking of PGN to this 70-kDa protein was competitively inhibited by LPS (IC50 = 7.3 microM), LPS from a deep rough mutant (IC50 = 6.9 microM), and lipid A (IC50 = 18-72 microM); (c) cross-linking of LPS to this 70-kDa protein was competitively inhibited by polymeric soluble PGN (IC50 = 0.09 microM) and sonicated high Mr PGN (IC50 = 0.6 microM); (d) cross-linking of both PGN and LPS to this 70-kDa protein was also competitively inhibited by dextran sulfate (IC50 = 115-124 microM); (e) cross-linking of both PGN and LPS to this 70-kDa protein was inhibited by a (GlcNAc)2-specific lectin; and (f) peptide maps of the 70-kDa proteins digested with chymotrypsin, subtilisin, staphylococcal protease V, or papain were identical for PGN- and LPS-binding proteins and unique for each enzyme. Based on competitive inhibition experiments, binding of PGN to the 70-kDa protein was 20-1200 times stronger than the binding of LPS or lipid A on a per mol basis. However, when aggregated micellar structures of LPS or lipid A were considered, the avidities of LPS and PGN binding were similar. These results demonstrate binding of PGN and LPS to the same 70-kDa protein on lymphocytes and suggest that the binding is specific for the (GlcNAc-MurNAc)n backbone of PGN and the (GlcNAc)2 part of lipid A.
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PMID:Peptidoglycan and lipopolysaccharide bind to the same binding site on lymphocytes. 200 21

An intracellular serine protease zymogen, factor C, is an initiator in the hemolymph coagulation system of horseshoe crab. We purified this zymogen from the hemocytes of the American horseshoe crab, Limulus (L.) polyphemus, the objective being to compare its properties with those of the Japanese horseshoe crab, Tachypleus (T.) tridentatus, factor C. The purified zymogen L.-factor C showed similar properties to those of T.-factor C, in terms of molecular mass (123,000), amino acid composition (1,011 residues), subunit structure (two chains), and antigenicity. Like the zymogen T.-factor C, this zymogen was also activated autocatalytically in the presence of bacterial lipopolysaccharide (LPS) and its synthetic lipid A analogue. A most interesting finding is that both protease zymogens are rapidly activated by alpha-chymotrypsin or rat mast cell chymase, but not by trypsin. The active enzyme factor C showed alpha-thrombin-like specificity toward synthetic tripeptide substrates. This factor C was also strongly inhibited by an alpha-thrombin inhibitor, D-Phe-Pro-Arg-chloromethyl ketone. Thus, the enzymatic properties of factor C are similar to those of mammalian alpha-thrombin. On the other hand, the coagulation cascade system present in the hemocyte lysate was activated when chymotrypsin, free from LPS, was added to the lysate used to detect the endotoxins. The implication of our findings is that the chymotrypsin-catalyzed initiation of the horseshoe crab coagulation system is unique, since all known mammalian coagulation, fibrinolysis and complement systems are initiated by trypsin-like enzymes.
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PMID:Further studies on lipopolysaccharide-sensitive serine protease zymogen (factor C): its isolation from Limulus polyphemus hemocytes and identification as an intracellular zymogen activated by alpha-chymotrypsin, not by trypsin. 201 64

An antiproliferative suppressor lymphokine was produced from rat T-cells specifically in response to the poorly immunogenic syngeneic mammary adenocarcinoma 13762A. The tumor-induced suppressor lymphokine (TISL) was produced late in culture (peak production on Days 4 and 5) and showed strong but selective inhibitory activity on a variety of immune responses. The immune peritoneal exudate cell response to a highly immunogenic clone from the parental tumor (clone 18A) and the concanavalin A-stimulated response of nonimmune spleen cells were inhibited strongly by TISL. In contrast, the immune spleen cell response to 13762A and the lipopolysaccharide response of nonimmume spleen cells were unaffected. Preliminary molecular weight and physicochemical analysis of TISL indicated that the molecule was large (Mr greater than 350,000); partially sensitive to 75 degrees C treatment for 15 min and to pH 2.0 treatment; only partly degraded by the enzymes trypsin, chymotrypsin, and proteinase K; and completely destroyed by boiling. Although TISL was produced specifically in response to 13762A tumor, prior immunization in vivo was not necessary for the induction of the suppressor lymphokine. These results indicate that populations of rat lymphocytes contain naturally occurring TISL secreting cells, which can be activated specifically by tumor antigens such as those expressed by 13762A.
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PMID:Suppressor lymphokine produced by rat T-cells in response to syngeneic mammary adenocarcinoma 13762A. 296 35

alpha 1-Antitrypsin (alpha 1-AT) is one of the major proteinase inhibitors in serum. Its primary physiological function is to inhibit neutrophil elastase activity in lung, but it also inhibits other serine proteases including trypsin, chymotrypsin, thrombin, and cathepsin. We have previously reported a novel alpha 1-AT, S-2 isoform, from rabbit that is induced up to 100-fold in the liver during acute inflammatory condition (Ray, B. K., Gao, X., and Ray, A. (1994) J. Biol. Chem. 269, 22080-22086). Here, we present evidence that the expression of this alpha 1-AT S-2 gene is also induced in lipopolysaccharide (LPS)-treated peripheral blood monocytes. From the cloned genomic DNA, we have identified a distal LPS-responsive enhancer located between -2438 and -1990 base pairs upstream of the transcription start site. In vitro DNA-binding studies demonstrated an interaction of an LPS-inducible NF-kappa B-like nuclear factor with a kappa B-element present in this enhancer region. Antibodies against p65 and p50 subunits of NF-kappa B supershifted the DNA-protein complex. A mutation of the NF-kappa B-binding element virtually abolished the LPS-responsive induction of the chimeric promoter in monocytic cells. Furthermore, overexpression of NF-kappa B induced the wild-type promoter activity. Taken together, these results demonstrated that during LPS-mediated inflammation, NF-kappa B/Rel family of transcription factors play a crucial role in the transcriptional induction of the inflammation responsive alpha 1-AT gene.
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PMID:Role of a distal enhancer containing a functional NF-kappa B-binding site in lipopolysaccharide-induced expression of a novel alpha 1-antitrypsin gene. 749 48

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

Bovine kappa-caseinoglycopeptides (i.e. residues 106-169, CGP) were prepared from kappa-casein digested with rennin and a commercial whey protein concentrate. CGP from whey protein concentrate was further divided into seven CGP fractions having different carbohydrate compositions using FPLC. Unfractionated CGP inhibited lipopolysaccharide (LPS)- and phytohaemagglutinin (PHA)-induced proliferative responses of mouse spleen cells and rabbit Peyer's patch cells. The unfractionated CGP also inhibited antibody responses to sheep red blood cells in mouse spleen cell cultures. However, seven CGP fractions having zero to five N-acetylneuraminic acid (NANA) residues had different inhibitory effects on both LPS- and PHA-induced proliferative responses of mouse spleen cells. The inhibitory effect on PHA-induced proliferative responses increased with increasing numbers of NANA residues, whereas that on LPS-induced proliferation was highest with the CGP fraction having two NANA residues. Both inhibitory effects decreased significantly after neuraminidase or chymotrypsin digestion. These findings indicate that both the carbohydrate (particularly the NANA residues) and the polypeptide portions are essential for inhibitory effects on LPS- and PHA-induced proliferative responses of mouse spleen cells.
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PMID:Inhibition of mitogen-induced proliferative responses of lymphocytes by bovine kappa-caseinoglycopeptides having different carbohydrate chains. 760 79

The influence of the alkylphosphocholines (APC) on macrophage activation to tumor cytotoxicity was investigated in vitro with both mouse peritoneal and rat liver macrophages. For this purpose the compounds were used either in micellar or in liposomal form. The cytotoxic effect of micellar or liposomal APC was increased with prolongation of the aliphatic chain and was reduced for the liposomal form. Peritoneal macrophages incubated with APC-liposomes gave a comparable cytotoxic effect on MethA cells to that of the free, highly toxic APC alone. These liposomes can activate rat liver macrophages (Kupffer cells) in vitro to a moderate tumor cytotoxicity on C26 colon carcinoma cells, while the micellar APC were toxic to macrophages. A significant release of NO-radicals from peritoneal macrophages was obtained with Liposomes but not with micellar lipid. The release of tumor necrosis factor (TNF) was stimulated by incubation with micellar or liposomal HPC. Whereas the micellar HPC was comparable to lipopolysaccharide (LPS) in TNF release stimulation, the HPC-liposomes caused a much higher release.
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PMID:Cytotoxic effects of alkylphosphocholines or alkylphosphocholine-liposomes and macrophages on tumor cells. 784 11


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