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)

Our present understanding of the pathogenesis of fever is that host macrophages, following activation by an appropriate stimulus such as Gram-negative lipopolysaccharide (LPS) immune complexes, or primed lymphocytes in the presence of specific antigen, synthesize and release endogenous pyrogen (EP). EP is carried in the blood circulation to the hypothalamic area of the brain where its action, involving a protein synthetic step, results in an increase of the level at which body temperature is maintained. Recently, it was shown that EP is very similar and possibly identical to another macrophage mediator previously called lymphocyte activating factor and now known as interleukin-1 (IL-1) which, in conjunction with lectin or specific antigen, induces clonal expansion of T lymphocytes. We show here that murine T-cell proliferation in response to IL-1 in vitro is greatly increased when the cells are exposed to a temperature typical of fever and that injection of the same IL-1 causes fever in mice. If this relationship exists in vivo, the resulting facilitation of a T-cell-dependent immune response may well confer survival value and contribute to the evolutionary conservation of fever--a phylogenetically ancient response to infection.
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PMID:The pyrogenic and mitogenic actions of interleukin-1 are related. 660 77

C6 glioma cells, and primary cultures of mouse astrocytes, stimulated with lipopolysaccharide (LPS) release an interleukin-1 like factor (IL-1) which enhances lectin-induced T-lymphocyte proliferation and promotes the release of interleukin-2 (IL-2) by ConA-stimulated thymocytes. In the present study, the glia maturation factor (GMF) was found not only to induce differentiation of glioblasts, but also to elicit the secretion of IL-1 like factors by cultured mouse astrocytes and their precursor cells. GMF was also effective in triggering IL-1 release by macrophages. Contamination of the 23 000 MW GMF preparation with LPS was excluded by the Limulus lysate assay and by using C3H/HeJ LPS-nonresponder mice whose glia and macrophages responded to GMF but not to LPS, by IL-1 release. Through its ability to induce glial differentiation and IL-1 release, GMF may represent an important endogenous signal, triggering both reactive gliosis and the development of an immune response within the central nervous system.
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PMID:Dual effect of glia maturation factor on astrocytes. Differentiation and release of interleukin-1 like factors. 660 46

Macrophages and P388D1 murine cultured cells produce interleukin 1 (lymphocyte-activating factor) when stimulated with lipopolysaccharide or other agents. Poly A+ RNA extracted from either type of stimulated cells and injected into Xenopus oocytes causes synthesis of material with the biologic and biochemical properties of interleukin 1. It potentiates lectin-mediated thymocyte proliferation, and it has the molecular dimensions of interleukin 1, as determined by gel exclusion chromatography. RNA from either cell type causes the synthesis of interleukin 1 with an isoelectric point of 4.8 to 5.0. RNA prepared from unstimulated macrophages or P388D1 cells does not cause interleukin 1 production by oocytes. We conclude that the amount of interleukin 1 mRNA increases greatly after stimulation of either cell type, and oocytes carry out any modifications of the polypeptide necessary for activity. The kinetics of interleukin 1 mRNA accumulation and of interleukin 1 production by macrophages and P388D1 cells are compared.
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PMID:Induction of interleukin 1 messenger RNA and translation in oocytes. 660 84

The effect of parent lipopolysaccharide (LPS) and radio-detoxified endotoxin (rdLPS) on various human blood cell membranes proved to be different as detected by 3H-concanavalin A-binding technique in vitro. The lectin-binding ability of erythrocyte membranes did not change upon treatment by either endotoxin, whereas that of lymphocytes was stimulated by LPS at 10-50 micrograms/ml concentration as well as by rdLPS at the lowest dose applied, i.e. 0.1 micrograms/ml. The LPS-treated platelets bound 3H-concanavalin A less than did the untreated controls; on the other hand, the rdLPS did not change the lectin-binding surface of these cells. The affection by radiation of cell membranes could be prevented by pretreatment with endotoxins. This fact, however, could not be considered a radioprotective effect. The micromorphological investigations by scanning electron microscopy (SEM) support our data concerning the functional alterations of plasma membranes of platelets and lymphocytes after LPS and rdLPS treatment as well as after the combined effect of endotoxin pretreatment and X-irradiation, since a severe smoothening of the cell surface could be observed.
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PMID:Effect of endotoxin and radio-detoxified endotoxin on cell membranes in vitro. 676 32

Strains of Neisseria gonorrhoeae were treated with pyocin 611 131 (pyocin 103) from Pseudomonas aeruginosa PA103, and isogenic resistant variants were isolated. The interaction of pyocin-sensitive and isogenic pyocin-resistant strains with wheat germ agglutinin (WGA) agglutinated all pyocin-sensitive, but not pyocin-resistant, strains. Binding of WGA to three pyocin-sensitive strains and their isogenic pyocin-resistant variants was examined quantitatively by using fluorescein-conjugated lectin. Pyocin-resistant strains maximally bound one-third to one-eighth the quantity of WGA bound by isogenic-sensitive strains. Linear Scatchard plots revealed homogeneous WGA-binding sites on three pyocin-sensitive and one pyocin-resistant strains. Biphasic Scatchard plots, obtained with two pyocin-resistant strains, show that WGA-binding sites in these strains are heterogeneous. The number of WGA-binding sites for pyocin-sensitive organisms ranged from 8 x 10(5) to 1 x 10(6) sites per coccus and from 1 x 10(5) to 3 x 10(5) sites per coccus for pyocin-resistant strains. The apparent association constant for WGA binding to pyocin-sensitive strains ranged from 3 x 10(6) to 6 x 10(6) liters/mol and from 6 x 10(6) to 1 x 10(7) liters/mol for pyocin-resistant strains. Gonococcal lipopolysaccharide was shown to serve as the pyocin 103 receptor by inhibition of pyocin activity. Lipopolysaccharide from a pyocin 103-resistant strain was not able to inhibit pyocin 103 activity. Pyocin 103 resistance was correlated with a structural alteration involving N-acetylglucosamine residues in gonococcal lipopolysaccharide. Based on interactions with wheat germ, soybean, and ricin lectins, a model of lipopolysaccharide structure in N. gonorrhoeae is presented.
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PMID:Interaction with lectins and differential wheat germ agglutinin binding of pyocin 103-sensitive and -resistant Neisseria gonorrhoeae. 679 62

Analysis of the surface constituents of a pyocin 611 131-resistant variant of strain no. JW-31 of Neisseria gonorrhoeae revealed substantial differences in the lipopolysaccharide (LPS) but not changes in the auxotype or outer-membrane proteins. Immunodiffusion and an enzyme-linked immunosorbent assay showed that the variant strain (no. JW-31R) lost both the LPS serotype and the variable antigens while retaining at least a portion of the common determinant. The use of monoclonal antibody indicated that LPSs from strain no. JW-31R and pyocin 611 131-resistant strains of other LPS serotypes lack a D-galactosaminyl-D-galactopyranosyl-D-glucose moiety. The LPS-derived polysaccharide from strain no. JW-31 binds to wheat-germ lectin in precipitin and inhibition systems, whereas the JW-31R polysaccharide exhibits a markedly reduced affinity. In the presence of normal human serum, 99% of strain no. JW-31R was killed within 20 min and strain no. JW-31 was not.
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PMID:Isolation of a lipopolysaccharide mutant of Neisseria gonorrhoeae: an analysis of the antigenic and biologic difference. 679 35

To examine directly the hypothesis that T cell growth factor (TCGF) interacts with target cells in a fashion similar to polypeptide hormones, the binding of radiolabeled TCGF to various cell populations was investigated. The results indicate that TCGF interacts with activated T cells via a receptor through which it initiates the T cell proliferative response. Internally radiolabeled TCGF, prepared from a human T leukemia cell line and purified by gel filtration and isoelectric focusing, retained biological activity and was uniform with respect to size and charge. Binding of radiolabeled TCGF to TCGF-dependent cytolytic T cells occurred rapidly (within 15 rain at 37 degrees C) and was both saturable and largely reversible. In addition, at 37 degrees C, a receptor- and lysosome-dependent degradation of TCGF occurred. Radiolabeled TCGF binding was specific for activated, TCGF-responsive T cells. Whereas unstimulated lymphocytes of human or murine origin and lipopolysaccharide-activated B cell blasts expressed few if any detectable binding sites, lectin- or alloantigen-activated cells had easily detectable binding sites. Moreover, compared with lectin- or alloantigen-activated T cells, long-term TCGF-dependent cytolytic and helper T cell lines and TCGF-dependent neo-plastic T cell lines bound TCGF with a similar affinity (dissociation constant of 5-25 pM) and expressed a similar number of receptor sites per cell (5,000-15,000). In contrast, a number of TCGF-independent cell lines of T cell, B cell, or myeloid origin did not bind detectable quantities of radiolabeled TCGF. Binding of radiolabeled TCGF to TCGF-responsive cells was specific, in that among several growth factors and polypeptide hormones tested, only TCGF competed for binding. Finally, the relative magnitude of T cell proliferation induced by a given concentration of TCGF closely paralleled the fraction of occupied receptor sites. As the extent of T cell clonal expansion depends on TCGF and on the TCGF receptor, the dissection of the molecular events surrounding the interaction of TCGF and its receptor that these studies permit, should provide new insight into the hormonelike regulation of the immune response by this lymphokine.
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PMID:T cell growth factor receptors. Quantitation, specificity, and biological relevance. 697 47

A lipopolysaccharide (LPS)-binding lectin was recovered from the serum of Limulus polyphemus by ion-exchange chromatography. Electrophoretic analysis of this lectin preparation revealed three poorly migrating bands. When whole serum was incubated with glycolipid obtained from the Rc mutant of Salmonella minnesota prior to electrophoresis, bands corresponding to those seen in the partially purified lectin were missing, suggesting that the recovered material was composed of isolectins. Qualitative precipitin tests revealed no reactivity of this purified lectin with lipid A fractions or with LPS devoid of 2-keto-3-deoxyoctonate (KDO). The agglutination of chicken erythrocytes by this lectin was inhibited by both N-acetyl-neuraminic acid and KDO. Erythrocytes complexed with glycolipid from the Re mutant of S. minnesota were strongly agglutinated by this lectin. We conclude that this LPS-binding lectin is specific for the KDO portion of the molecule and that it is identical to the previously described sialic acid-binding lectin from L. polyphemus. This lectin may play a role in the host defense mechanisms of Limulus.
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PMID:Lipopolysaccharide-binding lectin from the horseshoe crab, Limulus polyphemus, with specificity for 2-keto-3-deoxyoctonate (KDO). 704 48

Immunoelectron microscopy was combined with partial characterization of isolated exopolysaccharide to study binding of soybean lectin by Rhizobium japonicum strain USDA 138. Lectin-binding activity resided in two forms of exopolysaccharide produced during growth: an apparently very high-molecular-weight capsular form and a lower-molecular-weight diffusible form. At low-speed centrifugation, the capsular form cosedimented with cells to form a viscous, white, cell-gel complex which was not diffusible in 1% agar, and the diffusible form remained in the cell-free supernatant. Electron microscopic observation of the cell-gel complex after labeling with soybean lectin-ferritin conjugate revealed that capsular polysaccharides, frequently attached to one end of the cells, were receptors for lectin. The outer membrane of the cell bound no lectin. Various preparations of exopolysaccharide isolated from the culture supernatant were tested for lectin binding, interaction with homologous somatic antigen, and the presence of 2-keto-3-deoxyoctonate and were chromatographed in Sepharose 4B and 6B gel beds. Lectin binding was restricted to a polysaccharide component designated as lectin-binding polysaccharide. This polysaccharide, as present in the cell-free culture supernatant, was a diffusible acidic polysaccharide devoid of 2-keto-3-deoxyoctonate, with a molecular weight of 2 X 10(6) to 5 X 10(6). It was concluded that the soybean lectin-binding component of R. japonicum is an extracellular polysaccharide and not a lipopolysaccharide and that the diffusible lectin-binding polysaccharide probably differs from the very high-molecular-weight lectin-binding polysaccharide of the loose capsule (slime) only in the degree of polymerization.
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PMID:Localization and partial characterization of soybean lectin-binding polysaccharide of Rhizobium japonicum. 719 4

Galactose metabolism mutants of Erwinia amylovora were created by transposon insertions and characterized for their growth properties and interaction with plant tissue. The nucleotide sequence of the galE gene was determined. The gene, which encodes UDP-galactose 4-epimerase, shows homology to the galE genes of Escherichia coli, Neisseria gonorrhoeae, Rhizobium meliloti, and other gram-negative bacteria. Cloned DNA with the galE and with the galT and galK genes did not share borders, as judged by the lack of common fragments in hybridization with chromosomal DNA. These genes are thus located separately on the bacterial chromosome. In contrast to the gal operon of E. coli, the galE gene of E. amylovora is constitutively expressed, independently of the presence of galactose in the medium. The function of the galE gene but not of the galT or galK gene is required for bacterial virulence on pear fruits and seedlings. In the absence of galactose, the galE mutant was deficient in amylovoran synthesis. Subsequently, the galE mutant cells elicited host defense reactions, and they were not stained by fluorescein isothiocyanate-labelled lectin, which efficiently binds to amylovoran capsules of E. amylovora. The mutation affected the side chains of bacterial lipopolysaccharide, but an intact O antigen was not required for virulence. This was shown with another mutant, which could be complemented for virulence but not for side chain synthesis of lipopolysaccharide.
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PMID:Genetics of galactose metabolism of Erwinia amylovora and its influence on polysaccharide synthesis and virulence of the fire blight pathogen. 750 2


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