Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Expression of the lysozyme gene is a marker for the differentiation of macrophages, lysozyme transcription being gradually increased during maturation. We have analyzed the fine structure and function of two macrophage-specific enhancer elements of the chicken lysozyme gene (E-2.7 kb and E-0.2 kb). Both increase their activities upon LPS induction, both contain multiple binding sites for similar or identical nuclear factors and both can be divided into two functional modules. For the E-0.2 kb enhancer we found a synergistic activity of the modules to be dependent on their distance. Binding sites for nuclear proteins within enhancer E-0.2 kb overlap substantially with the previously identified progesterone/glucocorticoid receptor binding site, which is required for steroid induction of lysozyme transcription in the oviduct.
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PMID:Cooperative interaction of chicken lysozyme enhancer sub-domains partially overlapping with a steroid receptor binding site. 276 16

The subcellular location of IL-1 beta was determined using a postsectioning immunoelectron microscopic method on ultrathin frozen sections of human monocytes stimulated with LPS. This methodology permits access of antibody probes to all sectioned intracellular compartments, and their visualization at high resolution. Staining was performed with a rabbit antibody that specifically recognized amino acids 197-215 in the 33-kD IL-1 beta precursor molecule, followed by affinity-purified goat anti-rabbit IgG conjugated to 10 nm colloidal gold particles. Approximately 90% of the IL-1 beta antigens were localized in the ground substance of the cytoplasm at 4 or 20 h after activation, when both intracellular and extracellular accumulation of IL-1 beta was well underway. No significant IL-1 beta staining was observed on the outer cell membrane, nor within the lumens of the endoplasmic reticulum (ER), the Golgi apparatus, or secretory vesicles. In contrast, lysozyme was localized in the ER and dense secretory granules using these methods. Our results suggest that IL-1 beta is not anchored on the plasma membrane, and that its secretion occurs by a novel mechanism that does not use a secretory leader sequence, nor the classical secretory pathway involving the ER and Golgi apparatus.
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PMID:Interleukin 1 beta is localized in the cytoplasmic ground substance but is largely absent from the Golgi apparatus and plasma membranes of stimulated human monocytes. 327 53

A cell line, HAFTL-1, derived by in vitro transformation of fetal liver cells with v-Ha-ras, was found to have molecular and phenotypic characteristics of pro-B cells recently committed to the Ly-1+ B cell differentiation pathway. Stimulation of these cells with LPS resulted in their differentiation within either the B or myelomonocytic lineages. Thus, lines derived from LPS-stimulated HAFTL-1 cells were shown to be clonally related, as evidenced by common v-ras integrations, but to exhibit characteristics of pre-B cells (ThB expression, continuing DJ heavy chain rearrangements) or mature macrophages (expression of Mac-1 and Mac-2, lysozyme and nonspecific esterase production, phagocytosis) while maintaining their Ly-1+ phenotype. These results suggest that events resulting in the irrevocable commitment to a single lineage occur late in differentiation, at least within the pathway yielding Ly-1+ B cells and a proposed subpopulation of Ly-1+ monocytes and macrophages. Final commitment to these lineages is carefully orchestrated, as evidenced by restricted expression of Ly-5 isoforms and production of IgH transcripts.
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PMID:Relationships between B cell and myeloid differentiation. Studies with a B lymphocyte progenitor line, HAFTL-1. 329 35

The effects of purified Salmonella endotoxin (LPS) and of LPS combined with isolated human plasma high density lipoproteins (HDL) on oxidative metabolism, measured by nitroblue tetrazolium (NBT)-test, and on lysozyme release of human granulocytes have been studied in vitro. A considerable increase in the NBT-reduction and in lysozyme release was noted in granulocytes exposed to LPS. The stimulating effect of LPS on NBT-reduction and lysozyme release was significantly diminished when the cells were incubated with LPS together with HDL. These observations suggest that HDL in vivo may play an important part in inhibition of metabolic changes induced in granulocytes by LPS which leads to the production and secretion of tissue damaging mediators.
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PMID:High-density lipoproteins inhibit the bacterial lipopolysaccharide mediated increase in oxidative metabolism and lysozyme release by neutrophilic granulocytes in vitro. 356 Jan 91

Polypeptide and polysaccharide outer membrane components of Brucella abortus 99 (S) were investigated by analysis of cell-wall fractions by sodium dodecyl-sulfate polyacrylamide gel electrophoresis and staining with coomassie blue and periodic acid silver stain. Crude cell-walls were deprived by Triton X-100 treatment of most cytoplasmic material as seen by electron microscopy and cytochrome determination (cell-walls). They were submitted to hot SDS to obtain intentionally after centrifugation, peptidoglycan in the insoluble fraction: SDS-I fractions or peptidoglycan sacculi, and outer membrane components in the SDS soluble fraction as for Enterobacteriaceae. The SDS-soluble fraction contained two major components: a high molecular weight broad band of smooth lipopolysaccharide (S-LPS) and a 43k polypeptide band. The SDS-I fractions were treated by lysozyme to solubilize peptidoglycan before analysis. They contained two major polypeptide groups 36-37-38k, 25-26-27k, a minor one at 31k and variable amounts of high molecular weight S-LPS. The polypeptide and polysaccharide patterns of the entire outer membrane obtained from lysozyme hydrolysed cell-walls are the sum of both SDS soluble and insoluble fraction patterns. These results mean that 25-27k and 36-38k bands are strongly bound to peptidoglycan, probably covalently. The 25-26-27k bands heavily stained for polysaccharides would be glycopolypeptides. In addition, the polysaccharide patterns of S-LPS fraction appears as a high molecular weight broad band, contrary to the multiple regularly spaced bands of high molecular weight E. coli S-LPS. The B. abortus outer membrane is composed of four major components: LPS, 43k and 36-37-38k polypeptides and 25-26-27k glycopeptides.
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PMID:Evidence of three major polypeptide species and two major polysaccharide species in the Brucella outer membrane. 641 68

The lipopolysaccharides ( LPSs ) from strains of Rhizobium leguminosarum, Rhizobium trifolii, and Rhizobium phaseoli were isolated and partially characterized by mild acid hydrolysis and by polyacrylamide gel electrophoresis. Mild acid hydrolysis results in a precipitate which can be removed by centrifugation or extraction with chloroform. The supernatant contains polysaccharides which, in general, are separated into two fractions ( LPS1 and LPS2 ) by Sephadex G-50 gel filtration chromatography. The higher-molecular-weight LPS1 fractions among the various Rhizobium strains are highly variable in composition and reflect the variability reported in the intact LPSs (R. W. Carlson and R. Lee, Plant Physiol. 71:223-228, 1983; Carlson et al., Plant Physiol. 62:912-917, 1978; Zevenhuizen et al., Arch. Microbiol. 125:1-8, 1980). The LPS1 fraction of R. leguminosarum 128C53 has a higher molecular weight than all other LPS1 fractions examined. All LPS2 fractions examined are oligosaccharides with a molecular weight of ca. 600. The major sugar component of all LPS2 oligosaccharides is uronic acid. The LPS2 compositions are similar for strains of R. leguminosarum and R. trifolii, but the LPS2 from R. phaseoli was different in that it contained glucose, a sugar not found in the other LPS2 fractions or found only in trace amounts. Polyacrylamide gel electrophoretic analysis shows that each LPS contains two banding regions, a higher-molecular-weight heterogeneous region often containing many bands and a lower-molecular-weight band. The lower-molecular-weight bands of all LPSs have the same electrophoretic mobility, which is greater than that of lysozyme. The banding pattern of the heterogeneous regions varies among the different Rhizobium strains. In the case of R. leguminosarum 128C53 LPS, the heterogeneous region of a higher molecular weight than is this region from all other Rhizobium strains examined and consists of many bands separated from one another by a small and apparently constant molecular weight interval. When the heterogeneous region of R. Leguminosarum 128C53 LPS was cut from the gel and analyzed, its composition was found to be that of the intact LPS, whereas the lower-molecular-weight band contains only sugars found in the LPS2 oligosaccharide. In the case of R. leguminosarum 128C63 and R. trifolii 0403 LPSs, the heterogeneous regions are similar and consist of several band s separated by a large-molecular-weight interval with a the major band of these heterogeneous regions having the lowest molecular weight with an electrophoretic mobility near that of beta-lactoglobulin. The heterogeneous region from R. phaseoli 127K14 consists of several bands with electrophoretic mobilities near that of beta-lactoglobulin, whereas this region from R. trifolii 162S7 shows a continuous staining region, indicating a great deal of heterogeneity. The results described in this paper are discussed with regard to the reported properties of Escherichia coli and Salmonella LPSs.
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PMID:Heterogeneity of Rhizobium lipopolysaccharides. 672 8

Antigen-specific tolerance was induced in mice by lethal irradiation followed by reconstitution with syngeneic, anti-T-cell-treated bone marrow and injection of the protein antigen lysozyme. Animals tolerized with lysozyme responded normally to a second antigen, sheep red blood cells, and animals treated with the same tolerizing regimen using a different protein antigen, bovine serum albumin, responded normally to lysozyme. Challenge of the tolerant mice with lysozyme covalently coupled to LPS induced an antilysozyme response indicating that if tolerance was expressed on the B-cell level that antigen-specific B-cells were still present. These results eliminate clonal abortion and clonal selection as the mechanism of tolerance generation. The tolerance generated by this procedure is either expressed on the T-cell level or is produced by a state of B-cell clonal anergy which can be overcome by the use of antigen coupled to lipopolysaccharide.
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PMID:Induction of tolerance to a soluble antigen following irradiation and bone marrow reconstitution. 675 40

A hen egg-white lysozyme-lipopolysaccharide complex (HEL-LPS) can stimulate an in vitro IgG response, but only from HEL-primed B lymphocytes; unprimed cells only produce an IgM response. These conditions were used to determine whether IgG memory B cells are cryptically induced in B10 nonresponder (H-2b) mice after an HEL injection protocol. The usual i.p. immunization that triggers IgG memory production in congenic responder strain mice fails to yield IgG in vitro from HEL-primed B10 spleen cells after stimulation with HEL-LPS. However, injection protocols immunogenic for B10 mice do engender IgG-memory cells. These results imply that the T helper cell population necessary for triggering B cells to the IgG memory stage cannot develop in the nonresponder mouse, presumably due to HEL-specific T suppressor cells.
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PMID:The failure of nonresponder mice to develop IgG memory assessed by in vitro culture with an antigen-LPS conjugate. 697

In order to evaluate the possible role of the hepatic macrophage (H-M macrophage) in lipopolysaccharide-induced shock and disseminated intravascular coagulation (DIC), a technique has been developed for the isolation and maintenance in culture of rabbit H-M macrophage. Characterization of the resultant cell population by morphology, nonspecific esterase staining, phagocytosis of latex beads, by presence of Fc and C3b membrane receptors confirms a pure population of M macrophage without outgrowth of other cell types for up to 10 days in culture. The exposure in vitro of the H-M macrophage to LPS (either Salmonella minnesota R595 or Escherichia coli 0111:B4) stimulates a selective increase in activity of several cellular enzyme: LDH, lysozyme, plasminogen activator, and a procoagulant factor, with minimal changes in acid phosphatase and beta-glucuronidase detected. Concomitantly, both in vivo and in vitro treatment with LPS produces an apparent direct cellular toxicity. The combined effect of toxicity and selective stimulation and release of mediators in LPS-stimulated H-M macrophage may play a central role in the endotoxemic shock syndrome.
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PMID:The response of isolated rabbit hepatic macrophages (H-M macrophage) to lipopolysaccharide (LPS). 719 47

BCG infection of mice provides a convenient model to study natural and cellular immunity to mycobacteria and the mechanisms of granuloma formation and repair. We have used a range of macrophage (M phi) membrane molecules and secretory products to investigate resident M phi-pathogen interactions and T lymphocyte-dependent recruitment and activation of M phi in different tissues of immature, normal adult and gamma interferon deficient animals. In situ hybridization (ISH), RT-PCR and immunocytochemical analysis of M phi gene and product expression have been correlated with in vitro study of endocytic and secretory activity in which biogel polyacrylamide bead-elicited peritoneal M phi are exposed to Th1 and Th2 cytokines, LPS, BCG and other stimuli. The role of resident and newly recruited M phi responding to BCG in liver, spleen, lung and brain has been defined by means of antigen markers expressed by M phi (F4/80, 7/4, CR3, macrosialin, sialoadhesin and scavenger receptor) and/or T and B lymphoid cells (MHC Class II, CD4, CD8, B220). Heterogeneity in M phi secretory activity was revealed by ISH analysis of lysozyme, TNF-alpha, IL-1 IL-6 and MCP-1, by in vitro assay of NO and superoxide anion production, and by RT-PCR studies of Th1 (interferon gamma) and Th2 (IL-4, IL-13, IL-10) lymphokine mRNA in tissues. Our studies confirm the importance of interferon gamma as a critical mediator of host resistance to mycobacterial infection and raise intriguing questions in regard to T cell and M phi functional heterogeneity in distinct tissue microenvironments.
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PMID:BCG-induced granuloma formation in murine tissues. 771 50


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