Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A mutant strain of Escherichia coli (E. coli ML-35) was used to follow the kinetics of phagocytosis, perforation of the bacterial cell envelope, and inactivation of bacterial proteins by human neutrophils. This particular E. coli mutant strain has no lactose permease, but constitutively forms the cytoplasmic enzyme beta-galactosidase. This implies that the artificial substrate ortho-nitrophenyl-beta-D-galactopyranoside cannot reach the beta-galactosidase unless the bacterial cell envelope has been perforated. Thus, the integrity of the E. coli envelope can be measured simply by the activity of beta-galactosidase with this substrate. Indeed, ingestion of E. coli ML-35 by human neutrophils was followed by perforation of the bacteria (increase in beta-galactosidase activity). Subsequently, the beta-galactosidase activity decreased due to inactivation of the enzyme. With a simple mathematical model and a curve-fitting computer program, we have determined the first-order rate constants for phagocytosis, perforation, and beta-galactosidase inactivation. With 32 normal donors, we found an interdonor variation in these rate constants of 20% to 30% (SD) and an assay variance of 5%. The perforation process closely correlated with the loss of colony-forming capacity of the bacteria. This new assay measures phagocytosis and killing in a fast, simple, and accurate way; it is not hindered by extracellular bacteria. Moreover, this method also measures the postkilling event of inactivation of a bacterial protein, which permits a better detection of neutrophils deficient in this function. The assay can also be used for screening neutrophil functions without the use of a computer program. A simple calculation suffices to detect neutrophil abnormalities. Neutrophils from patients with chronic granulomatous disease (CGD) showed an impaired rate of perforation and thus also of inactivation. Neutrophils from myeloperoxidase-deficient patients or from a patient with the Chediak-Higashi syndrome only showed a retarded inactivation of beta-galactosidase, but normal ingestion and perforation. The role of myeloperoxidase in the killing process is discussed. Although myeloperoxidase does not seem to be a prerequisite for perforation, it probably plays a role in bacterial destruction by normal cells, because the inactivation of bacterial proteins seems strictly myeloperoxidase dependent.
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PMID:Kinetics and mechanism of the bactericidal action of human neutrophils against Escherichia coli. 608 60

Polymorphonuclear leucocytes were isolated from pig blood relatively free from other cells and were characterised biochemically and morphologically and compared with human PMNLs. The activities of 16 enzymes of porcine and human PMNLs were measured and compared. Alkaline phosphatase, acid phosphatase, phosphodiesterase, gamma-glutamyl transpeptidase, NADH-cytochrome c oxidoreductase, malate dehydrogenase and acetylcholinesterase had higher specific activities in procine than in human cells. Alkaline phosphatase has an 87-fold higher specific activity in porcine than in human cells. beta-glucuronidase, lysozyme, beta-galactosidase, N-acetyl-glucosaminidase, beta-glucosidase, myeloperoxidase and catalase had higher specific activities in human than in porcine cells. beta-glucuronidase and myeloperoxidase showed over a 1000- and a 13-fold higher specific activity, respectively, in human than in porcine cells. Porcine PMNLs are readily available in large numbers and are recommended for studies of phagocytosis, chemotaxis and membrane biochemistry.
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PMID:Biochemical characterisation of porcine polymorphonuclear leucocytes: comparison with human polymorphonuclear leucocytes. 687 22

Polymorphonuclear cells kill microorganisms by the stock of antibiotic proteins and peptides stored in their lysosomal granules and have the ability to produce reactive oxygen intermediates (ROI) such as H2O2, O2-, and HOCl. Since the components involved in the microbicidal functions of buffalo (Bos bubalis) polymorphonuclear cells (PMN) have not been characterized, an assessment was made of the levels of various enzymes, the extent of extracellular release of these enzymes, and also their ability to produce H2O2/O2- upon activation with opsonized zymosan (OZ) or lipopolysaccharide (LPS). Using GPC-HPLC, OZ was shown to be a more potent secretagogue than LPS, causing a significantly greater release of low-molecular-weight components. Varying levels of the enzymes (myeloperoxidase, lactate dehydrogenase, acid and alkaline phosphatases, beta-galactosidase, beta-D-glucuronidase, elastase and lysozyme) were recorded in the buffalo PMN and both the activators (OZ and LPS) caused significant release of all the enzymes except alkaline phosphatase. Both the activators also caused a significant increase in H2O2/O2- production by the PMN. However, OZ caused a more pronounced activation than LPS. The studies revealed the presence of oxygen-dependent and oxygen-independent microbicidal systems with buffalo PMN, which responded more effectively to zymosan activation.
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PMID:The effect of activation of granulocytes on enzyme release and hydrogen peroxide and superoxide production in buffaloes. 915 8

In the present study the level of enzyme hydrolases (alkaline phosphatase, myeloperoxidase, elastase, arginase, lysozyme and beta-galactosidase) of polymorphonuclear cell (PMN) granules in different ruminant species and their release in response to activation was studied. Buffalo PMN alkaline phosphatase activity was higher (P < 0.01) than in PMNs of cattle and goats. Interestingly, myeloperoxidase was higher in cattle PMNs and least in goat PMNs (P < 0.01), a similar pattern was observed in the distribution of enzyme arginase. As far as lysozyme is concerned, its activity was significantly higher (P < 0.01) in PMNs of buffaloes than in the case of cattle and goat PMNs. On activation, these cells released MPO and elastase, in all the species studied, while lysozyme was secreted only in buffalo PMN cells. Activity of certain enzymes related to oxidant defence systems such as glutathione peroxidase and glutathione reductase were higher in cattle and goats compared to that in buffaloes. These observations are likely to have bearing on immunodefense roles played by PMNs and reflected differences among the ruminant species studied.
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PMID:A comparative study on certain enzymes of the granulocyte from different ruminant species. 977 61

The present study was aimed at investigating whether the expression of Fas ligand (FasL) by CHO cells transfected with IL-4 (CHO/IL-4) or IL-10 (CHO/IL-10) genes would improve the effect of the cytokine. DBA/ 1 mice immunized with type II collagen were treated with suboptimal doses of transfected CHO cells (a single s. c. injection of 2 x 10(5) cells) around onset of arthritis. Severe collagen-induced arthritis (CIA) developed in the control groups injected with PBS, CHO /beta-galactosidase/FasL, CHO/IL-4 or CHO/IL-10 cells. In contrast, administration of CHO/IL-4/FasL, but not CHO/IL-10/FasL, cells significantly reduced the clinical severity and resulted in rapid and sustained suppressive effect. Amelioration of CIA was not due to a prolonged in vivo secretion of IL-4 since expression of FasL by CHO cells shortened the in vivo survival of the xenogeneic cells. In fact, administration of FasL(+) cells was associated with a decreased proportion of Mac1(+) neutrophils in the blood and an increased expression of myeloperoxidase at the site of engineered cell engraftment. These findings suggest that the mechanism underlying the beneficial effect of IL-4 delivered by cells expressing FasL involves the combination of the anti-inflammatory properties of IL-4 and the apoptosis of Fas(+) Mac1(+) granulocytes participating in the pathogenic process.
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PMID:Expression of Fas ligand improves the effect of IL-4 in collagen-induced arthritis. 1060 54

In this study, we have evaluated the role of cytokine-induced neutrophil chemoattractant (CINC), in the upregulation of neutrophil Ca(2+) signaling in neutrophils from thermally injured rats treated with anti-CINC antibody. Additionally, we have determined the effect of the treatment with CINC antibody on the accumulation of activated neutrophils in the intestinal wall, and the effect of such accumulation on gut bacterial translocation. Measurements of myeloperoxidase (MPO) activity and immunohistochemical localization of neutrophils determined neutrophil sequestration in the rat intestine. Agar culture analyses and a specific Escherichia coli beta-galactosidase gene polymerase chain reaction was carried out to detect gut indigenous bacterial invasion into intestinal wall and extraintestinal mesenteric lymph nodes (MLN). The results showed that pretreatment of rats with anti-CINC antibody attenuated the thermal injury-induced enhancement in [Ca(2+)](i) responses in neutrophils both in the basal and Formyl-Met-Leu-Phe stimulated conditions. Moreover, treatment with the CINC antibody decreased neutrophil infiltration into the gut and attenuated thermal injury-caused translocation of bacteria into the MLN.
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PMID:CINC blockade prevents neutrophil Ca(2+) signaling upregulation and gut bacterial translocation in thermal injury. 1111 31

The pathogenesis of progressive bile duct loss in primary biliary cirrhosis remains unclear. In this study, the involvement of cellular senescence of biliary epithelial cells was examined in liver tissue samples from patients with primary biliary cirrhosis (n = 33), and compared with control diseased and normal livers (n = 83). In addition, cellular senescence was induced by oxidative stress in cultured mouse biliary epithelial cells. Biliary epithelial cells in small bile ducts in primary biliary cirrhosis, especially those in patients presenting with chronic non-suppurative cholangitis, frequently expressed senescence-associated beta-galactosidase, and senescence-associated p16(INK4) and p21(WAF1/CIP). In contrast, senescence-associated markers were rarely expressed in small bile ducts in control livers. The infiltration of myeloperoxidase-positive inflammatory cells into biliary epithelial cell layers was closely associated with the cellular senescence of biliary epithelial cells in early-stage PBC. Cellular senescence of cultured mouse biliary epithelial cells was induced by treatment with H2O2 via the p38MAPK-dependent pathway and nitric oxide-augmented H2O2-induced cellular senescence. Oxidative stress- and nitric oxide-mediated cellular senescence may be involved in bile duct lesions, which are followed by progressive bile duct loss in primary biliary cirrhosis.
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PMID:Frequent cellular senescence in small bile ducts in primary biliary cirrhosis: a possible role in bile duct loss. 1568 90