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)

The purpose of this study was to examine whether Bacteroides (Porphyromonas) gingivalis fimbriae, an important structure involved in attachment of the bacteria to periodontal tissues, activate macrophages and subsequently induce gene expression and production of interleukin-1 (IL-1) in the cells. The fimbriae increased glucose consumption and lysozyme activity in BALB/c macrophages, both criteria of macrophage activation of peritoneal macrophages, in a dose-dependent fashion. A marked increase in the mRNA level of the c-myc gene, an oncogene, in the cells was observed after a 1-h treatment with the fimbriae, and the level decreased rapidly after 3 h. The fimbriae (4 micrograms of protein per ml) markedly induced IL-1 alpha and IL-1 beta gene expression in the cells and IL-1 production. The expression of IL-1 alpha and IL-1 beta genes measured in terms of specific mRNA increased 1 h after the start of treatment and peaked at 6 h. Such increased expression of IL-1 beta was also observed in C3H/HeJ mice, a lipopolysaccharide low-responder strain. The fimbriae stimulated transcriptional activity of IL-1 beta in the cells, but not that of IL-1 alpha. We also observed that fimbriae-induced IL-1 gene expression was not regulated by endogenous prostaglandin triggered by the fimbriae. Therefore, these observations suggest that B. gingivalis fimbriae may be involved in the pathogenesis of adult periodontal disease via triggering of IL-1 production by monocytes/macrophages in periodontal diseases.
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PMID:Bacteroides (Porphyromonas) gingivalis fimbriae activate mouse peritoneal macrophages and induce gene expression and production of interleukin-1. 170 18

Bombesin, gastrin-related peptide (GRP), and related peptides sharing the common carboxyterminal sequence stimulate lactoferrin (serous cell marker) and glycoconjugate (mucous cell and goblet cell marker) release from human nasal mucosal explants in vitro. In vivo, GRP released from trigeminal sensory nerves may act upon GRP-bombesin binding sites on respiratory epithelial cells and submucosal glands. To determine whether GRP-bombesin can stimulate nasal secretion in vivo, bombesin was administered to eight normal subjects by unilateral, topical administration. Secretions from both nostrils were collected for measurement of total protein, lysozyme, hexose-containing glycoconjugates, and albumin (marker of vascular permeability). Baseline secretions contained 72.0 +/- 17.3 micrograms/ml of total protein, 14 +/- 2 micrograms/ml of lysozyme, 113 +/- 44 micrograms/ml of hexose-containing glycoconjugates, and 7.8 +/- 3.4 micrograms/ml of albumin. Hexose-containing glycoconjugate secretion was significantly increased after 1 nmol (385 +/- 63 micrograms/ml, P less than 0.001 by analysis of variance), 10, 100, and 1,000 nmol of bombesin, but the secretion was not dose dependent. Significant lysozyme (24 +/- 3 micrograms/ml, P less than 0.05) and total protein (155 +/- 23 micrograms/ml, P less than 0.01) secretion occurred after 1,000 nmol. No statistically significant changes in albumin secretion occurred at any dose. Saline had no significant effects on secretion. Therefore, bombesin stimulated secretion from submucosal glands and possibly epithelial cells in the human nose without affecting vascular permeability.
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PMID:Bombesin stimulates human nasal mucous and serous cell secretion in vivo. 173 81

Competitive hormone binding studies with membrane and partially purified receptors from Xenopus laevis oocytes revealed that the oocyte possesses high affinity (KD = 1-3 nM) binding sites for both insulin growth factors 1 and 2 (IGF-1 and IGF-2), but not for insulin. Consistent with these findings, IGF-1 activates hexose uptake by Xenopus oocytes with a KA (3 nM) identical with its KD, while IGF-2 and insulin activate hexose uptake with KA values of 50 nM and 200-250 nM, respectively, suggesting activation mediated through an IGF-1 receptor. Both IGF-1 and insulin activate receptor beta-subunit autophosphorylation and, thereby, protein substrate (reduced and carboxyamidomethylated lysozyme, i.e. RCAM-lysozyme) phosphorylation with KA values comparable to their respective KD values for ligand binding and KA values for activation of hexose uptake. The autophosphorylated beta-subunit(s) of the receptor were resolved into two discrete components, beta 1 and beta 2 (108 kDa and 94 kDa, respectively), which were phosphorylated exclusively on tyrosine and which exhibited similar extents of IGF-1-activated autophosphorylation. When added prior to autophosphorylation, RCAM-lysozyme blocks IGF-1-activated autophosphorylation and, thereby, IGF-1-activated protein substrate (RCAM-lysozyme) phosphorylation. Based on these findings, we conclude that IGF-1-stimulated autophosphorylation of its receptor is a prerequisite for catalysis of protein substrate phosphorylation by the receptor's tyrosine-specific protein kinase. The IGF-1 receptor kinase is implicated in signal transmission from the receptor, since anti-tyrosine kinase domain antibody blocks IGF-1-stimulated kinase activity in vitro and, when microinjected into intact oocytes, prevents IGF-1-stimulated hexose uptake.
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PMID:The insulin-like growth factor 1 (IGF-1) receptor is responsible for mediating the effects of insulin, IGF-1, and IGF-2 in Xenopus laevis oocytes. 185 44

A fluorescent compound has been detected in proteins browned during Maillard reactions with glucose in vitro and shown to be identical to pentosidine, a pentose-derived fluorescent cross-link formed between arginine and lysine residues in collagen (Sell, D. R., and Monnier, V. M. (1989) J. Biol. Chem. 264, 21597-21602). Pentosidine was the major fluorophore formed during nonenzymatic browning of ribonuclease and lysozyme by glucose, but accounted for less than 1% of non-disulfide cross-links in protein dimers formed during the reaction. Pentosidine was formed in greatest yields in reactions of pentoses with lysine and arginine in model systems but was also formed from glucose, fructose, ascorbate, Amadori compounds, 3-deoxyglucosone, and other sugars. Pentosidine was not formed from peroxidized polyunsaturated fatty acids or malondialdehyde. Its formation from carbohydrates was inhibited under nitrogen or anaerobic conditions and by aminoguanidine, an inhibitor of advanced glycation and browning reactions. Pentosidine was detected in human lens proteins, where its concentration increased gradually with age, but it did not exceed trace concentrations (less than or equal to 5 mumol/mol lysine), even in the 80-year-old lens. Although its precise carbohydrate source in vivo is uncertain and it is present in only trace concentrations in tissue proteins, pentosidine appears to be a useful biomarker for assessing cumulative damage to proteins by nonenzymatic browning reactions with carbohydrates.
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PMID:Formation of pentosidine during nonenzymatic browning of proteins by glucose. Identification of glucose and other carbohydrates as possible precursors of pentosidine in vivo. 190 67

Stimulated whole saliva was centrifuged and sterilized either by filtration in the presence or absence of dithiothreitol (DTT) or by ethylene oxide treatment. Filtration was accomplished by 2 different techniques: conventional positive pressure filtration through prefilters and membranes with decreasing pore sizes and tangential flow microporous filtration. The sterile saliva samples were analyzed for enzyme activities of phosphatases, esterases, glucuronidase, and lysozyme. The samples were also tested by polyacrylamide electrophoresis, isoelectric focusing and for IgA concentration. Moreover, the samples were tested for support of bacterial growth of strains from the genera Actinomyces, Lactobacillus, Neisseria, Rothia and Streptococcus after the addition of glucose at a final concentration of 0.5%. The samples treated with ethylene oxide appeared to be more affected by this treatment than samples treated otherwise, as demonstrated by the electrophoretic analyses and analyses of enzyme activities. Ethylene oxide-treated saliva also was the least favorable saliva sample to support growth of bacteria. The positive pressure technique gave more rapid filtration than the tangential flow technique. DTT treatment of saliva facilitated filtration and, in contrast to ethylene oxide treatment, it affected the qualities of saliva only to a minor extent compared with the original saliva sample.
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PMID:Biological qualities of saliva sterilized by filtration or ethylene oxide treatment. 194 2

Several previous findings have suggested that the cationic nature of lysozyme is a major factor in its bactericidal activity. Since a number of cationic proteins or peptides have been reported to cause membrane damage in bacteria, we investigated the effect of lysozyme on glucose fermentation and intracellular pH and K+ in Streptococcus mutans under conditions in which lysis does not occur. Results showed that lysozyme and poly-D-lysine (PDL) cause inhibition of glucose fermentation at pH 5.5 in a dose-dependent manner. Human placental lysozyme and hen egg-white lysozyme exhibited similar inhibitory potency on glucose fermentation. Both lysozyme and PDL caused a marked acidification of the cytoplasm of S. mutans. However, when cytoplasmic pH was examined as a function of fermentation rate, the relationship was similar regardless of the presence or absence of lysozyme or PDL. Therefore, acidification of the cytoplasm appeared to not depend specifically on lysozyme or PDL. In contrast, the same relationship between the profound loss of intracellular K+, when fermenting cells were exposed to either lysozyme or PDL, and the fermentation rate was not exhibited in the controls. These results indicate that lysozyme and PDL specifically affected the ability of the cells to maintain intracellular K+. We concluded that lysozyme and PDL indeed perturb membrane function, perhaps in a selective manner. Furthermore, the similarity in action of lysozyme and the cationic homopolypeptide PDL supports the notion that the cationic property of lysozyme indeed plays a significant role in its antibacterial activity.
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PMID:Effect of lysozyme on glucose fermentation, cytoplasmic pH, and intracellular potassium concentrations in Streptococcus mutans 10449. 198 80

The authors studied the effect of some factors, including the conditions of preincubation, the action of 2-mercaptoethanol, EDTA, alpha-amylase, on protoplast production in four strains of Streptococcus lactis caused by lysozyme. The strains differed in the nisin-producing activity and in the structure of the cell walls that were not affected with lysozyme without either preincubation in 2-mercaptoethanol or in a salt medium with minimal inhibitory concentrations of DL-threonine. EDTA and alpha-amylase increased the lysozyme effect. Among seven buffer systems studied the most favourable for protoplast production in S. lactis is the ammonia-citric buffer with EDTA, and the best regeneration medium is the agar salt medium to which, depending on the strain, either glucose or sucrose should be added as a stabilizer.
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PMID:[Various aspects of protoplast production in Streptococcus lactis]. 212 39

The basidiomycete Schizophyllum commune produces an extracellular bacteriolytic enzyme when grown on heat-killed cells of Bacillus subtilis as sole C, N and P source. The enzyme catalyses the dissolution of isolated B. subtilis cell walls at an optimum pH of 3.2-3.4, releasing muramyl reducing groups, which indicates that it is a muramidase. Although low levels of enzyme activity are present when the fungus is grown in the absence of bacteria, full enzyme production appears to be induced by bacterial cells and repressed by glucose. Whole bacteria are not lysed by the enzyme at pH 3.3, but are rendered osmotically fragile, and lyse when the pH is raised to 7 or higher. The muramidase is effective against several Gram-positive bacteria but did not lyse any of the Gram-negative species tested.
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PMID:A bacteriolytic muramidase from the basidiomycete Schizophyllum commune. 212 98

The injection of cane sugar factor (CSF) into Galleria mellonella larvae results in an immune response similar to that produced by a formalized Pseudomonas aeruginosa vaccine. Vaccination with CSF is followed by: an increase in the LD50 of Pseudomonas aeruginosa; an in vivo protective response to P. aeruginosa the development of which can be inhibited by cobra venom factor (CVF); an antibacterial activity in hemolymph 24 h after the injection of CSF; the development of a transferrable immune response in hemolymph of donor larvae capable of protecting recipient larvae against a lethal challenge of Pseudomonas aeruginosa; an increase in extracellular lysozyme equal to that induced by Pseudomonas vaccine; a reduction in total hemocyte count during the period of protective immunity; and the presence in hemolymph of new basic proteins, with electrophoretic mobilities and appearance times after the CSF injection, identical to those induced by the formalized vaccine. CSF was shown to be composed primarily of glucose.
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PMID:Cane sugar factor as an inducing agent of immunity in Galleria mellonella. 212 79

Lysozyme is a dominant member of the antibacterial complex of human saliva and has the potential to kill bacteria by direct lysis or by mechanisms (not completely understood) that are independent of its muramidase activity. The muramidase-independent bactericidal activity appears to depend upon its cationic character. Bacterial death may be due to inhibition of nutrient transport (eg. glucose) and disruption of membrane integrity. This review also describes common bactericidal mechanisms of several cationic peptides/proteins to support the cationic-dependent bactericidal model of lysozyme.
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PMID:Antibacterial mechanisms of lysozyme on Streptococcus mutans. 213 96


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