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 electrophoretic analysis of lipid A-associated protein (LAP), obtained from S. sonnei, in polyacrylamide gel in the presence of sodium dodecyl sulfate and urea has revealed the heterogeneity of the preparation; it has found to contain three main components with molecular weights of 43, 38 and 18 KD and some minor components with molecular weights of 49, 45 35, 30, 29, 27, 5, 21 and 14 KD. The electrophoretic mobility of the main protein components in the isolated preparation of LAP coincides with that of endotoxin components. The dissociation of proteins and lipopolysaccharide in the process of boiling the endotoxin in 2% sodium dodecyl sulfate is indicative of the noncovalent binding of these components. LAP contained in the endotoxin, in contrast to isolated LAP, is resistant to trypsin and proteinase K. The enzyme immunoassay (EIA) system with the use of LAP as a component of its solid phase has been developed, which makes it possible to carry out the quantitative determination of antibodies to this protein. The EIA system shows high sensitivity in the determination of anti-LAP IgG antibodies: in hyperimmune rabbit sera their titer is 1:250,000-1:800,000. As shown by the method of competitive EIA, the antigenic affinity of LAP of different origin corresponds to the degree of taxonomic propinquity of microorganisms: the maximal degree of cross reactions is observed between LAP obtained from S. sonnei, S. flexneri and Escherichia coli, while their affinity to Salmonella typhi is considerably less; remote microbial species (Bacterium bifidum and Sarcina marcescens) give practically no cross reactions.
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PMID:[Shigella endotoxin protein--its electrophoretic and serological properties]. 188 99

We have shown that certain murine tumors grow more slowly and spread less readily in immune deficient animals. We have also demonstrated that immunologic factors explain certain aspects of this difference. In the work presented we demonstrate that a subpopulation of splenocytes produce a factor(s) that enhances tumor cell proliferation in vitro. We also describe an in vitro model to determine the level of tumor stimulatory activity. We found that the tumor cell growth-enhancing activity (TEA) is heat stable but sensitive to trypsin digestion, low pH and beta-mercaptoethanol. TEA production is found to be insensitive to mitogen stimulation such as concanavalin A, lipopolysaccharide, and phytohemagglutinin. Among the known growth factors and interleukins we have tested (interleukin 1-7, basic FGF, EGF, TGF-beta PDGF, GM-CSF, and MCSF), none appear to account for TEA activity.
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PMID:Initial description of a tumor enhancing activity produced by murine splenocytes. 188 89

Mycoplasmas (M. gallisepticum, chicken mycoplasmas), in concert with interferon gamma (IFN gamma), were effective in activating macrophages (M theta) to be tumoricidal. The M theta-activating capacity of mycoplasmas was maintained after treatment with heat. 0.1 M NaOH, 1 M HCl, or trypsin. M theta-activating factor was extracted from mycoplasmas with chloroform/methanol and water (Mf-B). Mf-B was also effective in activating M theta in the presence of IFN gamma. The threshold dose of Mf-B for M theta of ordinary C3H/He mice and that for those of C3H/HeJ mice, the latter being known to be low responders to bacterial lipopolysaccharide, were actually the same. This seems to indicate that the effectiveness of Mf-B was not attributable to possibly contaminating lipopolysaccharides, and that the pathway of activity of Mf-B is different from that of lipopolysaccharides. Since the M theta-activating principle was only a very small part of Mf-B, we have not yet succeeded in identifying it, but there was no evidence that it was protein, nucleic acid, sugar, or lipid. The cytotoxicity of M theta activated by Mf-B plus IFN gamma was dependent on L-arginine in the culture, suggesting that arginine metabolites are involved in M theta cytotoxicity. Mf-B induced a small amount of tumor necrosis factor in M theta, and this induction was markedly enhanced by IFN gamma.
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PMID:Macrophage-activating factor extracted from mycoplasmas. 190 96

Using a lipopolysaccharide affinity column and ion exchange chromatography, a 12-kDa protein has been purified from Limulus amebocytes. In solid phase binding assays, the radiolabeled protein binds specifically to lipopolysaccharide (LPS) with a Kd value on the order of 10(-7) M. A cDNA coding for this protein has been isolated and sequenced. The amino acid sequence deduced from the cDNA indicates that this protein shares no sequence homology with LPS-binding proteins isolated from different species of vertebrates (Schumann, R. R., Leong, S. R., Flaggs, G. W., Gray, P. W., Wright, S. D., Mathison, J. C., Tobias, P. S., and Ulevitch, R. J. (1990) Science 249, 1429-1431) and invertebrates (Aketagawa, J., Miyata, T., Ohtsubo, S., Nakamura, T., Morita, T., Hayashida, H., Miyata, T., Iwanaga, S., Takao, T., and Shimonishi, Y. (1986) J. Biol. Chem. 261, 7357-7365). The binding to LPS can be displaced by the unlabeled 12-kDa protein, polymyxin B, lipid A, and to a lesser extent by D-glucosamine. In whole cell binding assays, the 12-kDa protein has also been shown to bind to Escherichia coli. Using both [14C]casein and a synthetic substrate, the protein has been shown to inhibit the proteolytic activity of trypsin, with an IC50 of approximately 10(-7) M. In the presence of LPS, the antitryptic acitivity of the Limulus endotoxin-binding protein-protease inhibitor remains unaffected. The protein is a major component of the cytoplasmic proteins (1%). Immunocytochemical analysis reveals that this protein exists in the secretory granules of the amebocytes where enzymes and substrates for the clotting cascade reside. Based on the unusual dual functional properties, the newly isolated protein was named a "Limulus endotoxin-binding protein-protease inhibitor" (LEBP-PI).
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PMID:Purification and characterization of an endotoxin-binding protein with protease inhibitory activity from Limulus amebocytes. 193 27

Colicin M (Cma) displays a unique mode of action in that it inhibits peptidoglycan and lipopolysaccharide biosynthesis through interference with bactoprenyl phosphate recycling. Protection of Cma-producing cells by the immunity protein (Cmi) was studied. The amount of Cmi determined the degree of inhibition of in vitro peptidoglycan synthesis by Cma. In cells, immunity breakdown could be achieved by overexpression of the Cma uptake system. Full immunity was restored after raising the cmi gene copy number. In sphaeroplasts, Cmi was degraded by trypsin, but this could be prevented by the addition of Cma. The N-terminal end includes the only hydrophobic amino acid sequence of Cmi, suggesting a function in anchoring of Cmi in the cytoplasmic membrane. It is proposed that Cmi does not act catalytically but binds Cma at the periplasmic face of the cytoplasmic membrane, thereby resulting in Cma inactivation. Two other possible modes of colicin M immunity, interference of Cmi with the uptake of Cma, and interaction of Cmi with the target of Cma, were ruled out by the data.
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PMID:Binding of the immunity protein inactivates colicin M. 195 88

This paper describes the development of a murine bank of monoclonal antibodies against Bordetella pertussis toxin, filamentous hemagglutinin (FHA), pili, lipopolysaccharide (LPS), or outer membrane proteins (OMPs). Subunits S1, S2, S3 of pertussis toxin (PT) bound immunoglobulins and glycoproteins such as fetuin and haptoglobin in an unspecific manner. The specificity of monoclonal antibodies towards subunits S1, S2, S3 or S4 of PT could be demonstrated by using purified immunoglobulins or their Fab2 fragments. A set of FHA-specific monoclonal antibodies could be differentiated on the basis of their binding to the various breakdown products present in FHA preparations. Pili-specific monoclonal antibodies reacted with either native pili or denatured pilin, and both demonstrated serotype specificity. Monoclonal antibodies to Bordetella pertussis OMPs were directed to either the virulent phase-regulated trypsin-sensitive, detergent-extractable OMPs 92 kDa, 32 kDa, and 30 kDa or the non-virulent phase-expressed, not-trypsin sensitive OMPs 38 kDa, 33kDa, and 18 kDa.
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PMID:Description of a hybridoma bank towards Bordetella pertussis toxin and surface antigens. 198

Both macrophages and platelets play an important role in atherogenesis. We studied the effect of conditioned medium obtained from human monocyte-derived macrophages on in vitro platelet aggregation. Incubation of macrophage-conditioned medium (MCM) with platelets resulted in enhanced platelet aggregation (up to 35% difference between basal and MCM-stimulated activity), which was time dependent. This MCM effect on platelet function was increased both with time of mononuclear cell culturing (up to 10 days) and with the time of macrophage incubation in serum-free medium (up to 24 hours) prior to MCM collection. MCM from either cholesterol-loaded macrophages or from macrophages obtained from patients with familial hypercholesterolemia demonstrated a 37% and 20% increased effect, respectively, in comparison to MCM derived from normal subjects. Macrophage activation with lipopolysaccharide resulted in the harvesting of a MCM that enhanced platelet activity 60% more than MCM obtained from nonactivated cells. The active component of MCM was inhibited fivefold following heating at 100 degrees C for 10 minutes or after treatment with trypsin or protease, but was not affected by antioxidants. MCM activation of blood platelets may be of importance in atherogenesis. Understanding the mechanisms involved may contribute to an improved appreciation of the role of both platelets and macrophages in atherosclerosis.
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PMID:Secretory products from human monocyte-derived macrophages enhance platelet aggregation. 200 39

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

The assembly of outer membrane proteins of Escherichia coli was examined using the OmpF porin as a model. Since this protein is made as a precursor, which is processed to a protein of Mr 37,000 before being assembled into trimers in the outer membrane, we synthesized a modified OmpF, which lacked 16 out of 22 amino acid residues from its signal sequence, in a coupled transcription-translation system. This modified protein resembled the unfolded, monomeric OmpF in its electrophoretic behavior, but much of the protein apparently existed in a more tightly folded conformation as it was recognized by a monoclonal antibody specific to a surface epitope of the native, trimeric OmpF porin. At least some conformers of this protein could be further incorporated into outer membrane or lipopolysaccharide bilayers, and assembled into trimers. The trimers formed were trypsin-resistant and heat-stable in sodium dodecyl sulfate up to 70 degrees C, thus showing the characteristics of the native trimeric protein. These results extend our earlier observation that OmpF monomer secreted by spheroplasts of E. coli can be trimerized in vitro (Sen, K., and Nikaido, H (1990) Proc. Natl. Acad. Sci. U.S. A 87, 743-747) and show that the trimerization can occur, albeit at a low efficiency, with porin monomers synthesized in vitro, presumably not contaminated by membrane fragments or other components of the cell envelope. However, comparison of trimerization efficiency of the nascent in vitro product with that of the same product already exposed to aqueous medium, as well as with that of the spheroplast-secreted product, leads us to the working hypothesis that the trimerization process in intact cells is accelerated either by accessory components or by the conformational changes accompanying the secretion through the cytoplasmic membrane and that the reactions observed in this study represent only part of the physiological process.
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PMID:Trimerization of an in vitro synthesized OmpF porin of Escherichia coli outer membrane. 204 Jun 34

Human epidermal keratinocytes constitutively produce a variety of cytokines, including neutrophil chemotactic peptide named epidermal cell-derived thymocyte-activating factor, which has been later confirmed to be interleukin 1 (IL-1). Because recombinant IL-1 lacks chemotactic activity, in the present study, we examined the exact nature of the neutrophil chemotactic peptide in the culture supernatant of normal human epidermal keratinocytes. Normal human epidermal keratinocytes produced a neutrophil chemotactic factor, which was also chemotactic for T lymphocytes. Molecular sieve chromatography revealed an approximate molecular size of 11,000 daltons. The activity was retained after heating at 100 degrees C for 10 min, and at a pH between 4 and 11, but was partially inactivated at pH 3, or by trypsin treatment. The chemotactic activity was not inhibited by the treatment with anti-IL-1 antibody. Its production by keratinocytes was stimulated by IL-1 and lipopolysaccharide but not by UV irradiation, tumor necrosis factor-alpha or by interferon-gamma. The neutrophil chemotactic activity in vivo was confirmed by the intradermal injection of the factor into guinea pigs. Blocking study with monoclonal antibodies against NAP-1/IL-8 confirmed that the neutrophil chemotactic factor is IL-8.
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PMID:Normal human epidermal keratinocyte-derived neutrophil chemotactic factor. 207 75


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