Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microbioassays using bacteria or enzymes are increasingly applied to measure chemical toxicity in the environment. Attractive features of these assays may include low cost, rapid response to toxicants, high sample throughput, modest laboratory equipment and space requirements, low sample volume, portability, and reproducible responses. Enzymatic tests rely on measurement of either enzyme activity or enzyme biosynthesis. Dehydrogenases are the enzymes most used in toxicity testing. Assay of dehydrogenase activity is conveniently carried out using oxidoreduction dyes such as tetrazolium salts. Other enzyme activity tests utilize ATPases, esterases, phosphatases, urease, luciferase, beta-galactosidase, protease, amylase, or beta-glucosidase. Recently, the inhibition of enzyme (beta-galactosidase, tryptophanase, alpha-glucosidase) biosynthesis has been explored as a basis for toxicity testing. Enzyme biosynthesis was found to be generally more sensitive to organic chemicals than enzyme activity. Bacterial toxicity tests are based on bioluminescence, motility, growth, viability, ATP, oxygen uptake, nitrification, or heat production. An important aspect of bacterial tests is the permeability of cells to environmental toxicants, particularly organic chemicals of hydrophobic nature. Physical, chemical, and genetic alterations of the outer membrane of E. coli have been found to affect test sensitivity to organic toxicants. Several microbioassays are now commercially available. The names of the assays and their basis are: Microtox (bioluminescence), Polytox (respiration), ECHA Biocide Monitor (dehydrogenase activity), Toxi-Chromotest (enzyme biosynthesis), and MetPAD (enzyme activity). An important feature common to these tests is the provision of standardized cultures of bacteria in freeze-dried form. Two of the more recent applications of microbioassays are in sediment toxicity testing and toxicity reduction evaluation. Sediment pore water may be assayed directly or solvents may be used to extract the toxicants. Some of the solvents used for extraction of organic chemicals are themselves toxic to bacteria (e.g., dichloromethane), requiring exchange with a less toxic solvent (e.g., ethanol, methanol, DMSO). A modification of the Microtox test allows direct assay of solid-phase samples such as sediments. The toxicity reduction evaluation (TRE) must be carried out at wastewater treatment plants whose effluents fail toxicity standards. The TREs require numerous and repeated toxicity assays, thus favoring application of microbioassays. Presently, no single microbioassay can detect all categories of environmental toxicants with equal sensitivity. Therefore, a battery of tests approach is recommended. The differential sensitivity of alternative tests may, in fact, be exploited. Further research is needed to construct strains of genetically engineered microorganisms or isolate microorganisms or enzymes that respond to specific classes of toxicants. These can be combined into batteries appropriate for different environments or test objectives.
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PMID:Bacterial and enzymatic bioassays for toxicity testing in the environment. 150 75

The human kidney cell line 293 was generated by transfection of adenovirus DNA into normal human embryonic kidney (HEK) cells (Graham et al., 1977), whereas the human kidney cell lines ST-1i and STt-4i were generated by transfection of HEK cells with plasmids encoding SV40 viral oncogenes (Abcouwer et al., 1989). In this study, we examined kidney-specific enzyme activity levels in 293, ST-1i, and STt-4i cells to determine their ability to exhibit kidney-specific gene expression. Enzymes examined were leucine aminopeptidase (LAP), gamma-glutamyl transpeptidase (gamma-GTP), and the disaccharidases trehalase and maltase. Enzymatic activity levels were compared to three other kidney cell lines (MDCK, OK, and LLC-PK1) as well as to normal human embryonic kidney (HEK) cells and the human hepatoma cell line, Hep G2. Modulation of kidney-specific enzyme activities was assessed in response to several differentiation-inducing agents (adenosine, n-butyric acid, hexamethylene bisacetamide (HMBA), dimethyl sulfoxide (DMSO), N,N'-dimethylformamide (DMF), isobutyl methyl xanthine (IBMX), di butyryl cAMP, and retinoic acid). ST-1i and STt-4i exhibit elevated levels of LAP, gamma-GTP, trehalase, and maltase, consistent with their kidney cell origin, whereas 293 cells exhibit elevated levels of just gamma-GTP and maltase. Maltase and gamma-GTP enzyme activities in ST-1i and STt-4i cells were very responsive to the various inducing agents; 293 cells were less responsive at the inducer concentrations examined. None of the three human cell lines formed domes under any of the experimental conditions. In summary, ST-1i and STt-4i are comparable to normal HEK cells in expression of kidney-specific enzymes and in responsiveness to differentiation-inducing agents, in spite of continued expression of SV40 oncogenes.
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PMID:Kidney-specific enzyme expression by human kidney cell lines generated through oncogene transfection. 167 45

Reactive oxygen species have been found to be responsible for the tissue injury caused in experimental pyelonephritis in mice. The extent of lipid peroxidation (as assayed by malondialdehyde formation) was found to be increased significantly (p less than .001) in the infected group as compared to the normal mice. Superoxide dismutase and catalase (oxygen free radical scavengers) showed a significant decrease (p less than .001) in the extent of lipid peroxidation even in the presence of infection. Dimethyl sulfoxide, a hydroxyl ion scavenger, was however found to be effective only at 4 and 7 days postinfection (p less than .001). Allopurinol, an inhibitor of xanthine oxidase, did not significantly (p greater than .05) inhibit the formation of lipid peroxides, even upto 7 days postinfection. There was a significant decrease (p less than .05) in the activities of renal brush border membrane enzymes used as markers of renal tissue damage (i.e. alkaline phosphatase, leucine amino-peptidase and gamma-glutamyl transpeptidase) in the infected group as compared to the normal group. In the presence of superoxide dismutase, dimethylsulfoxide and catalase except allopurinol, the activities of all the enzymes but maltase were found to be increased significantly (p less than .05) as compared to the infected group. There was a significant increase (p less than .01) in the bacterial count in the presence of superoxide dismutase and DMSO in infected mice as compared to the infected control mice. However, no significant difference was observed in the catalase and allopurinol treated groups.
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PMID:Effect of various oxygen free radical scavengers in preventing tissue injury caused by Escherichia coli in pyelonephritic mice. 305 56

A novel derivative of vitamin E, vitamin E glucoside, was synthesized from 2-hydroxymethyl-2,5,7,8-tetramethylchroman-6-ol and maltose in a solution containing DMSO by transglycosylation with alpha-glucosidase from Saccharomyces species. The glycosylated product was identified as 2-(alpha-D-glucopyranosyl)methyl-2,5,7,8-tetramethylchroman-6-ol (TMG) by mass spectrometry and nuclear magnetic resonance spectroscopy. The optimal pH of transglycosylation was 5.5, and the yield of TMG increased as the concentration of maltose increased. TMG has high solubility in water (> 1 x 10(3) mg/mL). The 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity of TMG was found to be nearly the same as those of alpha-tocopherol, Trolox (2-carboxy-2,5,7,8-tetramethylchroman-6-ol), and ascorbic acid.
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PMID:Synthesis of a novel vitamin E derivative, 2-(alpha-D-glucopyranosyl) methyl-2,5,7,8-tetramethylchroman-6-ol, by alpha-glucosidase-catalyzed transglycosylation. 907 96

The synthesis, spectroscopic, enzyme-inhibition, and free-radical-scavenging properties of a series of vanadium(IV) complexes, compounds 1-10, were investigated. These complexes exhibit a dimeric structure with hydrazide ligands coordinated in a bidentate fashion. All complexes are stable in the solid state, but exhibit varying degrees of stability in solution. In coordinating solvent such as DMSO, stepwise binding of two solvent molecules at the 6th positions trans to the V double bond O bond of the dimeric unit is observed. The dimeric compounds are converted to monomeric species in which both solvent molecules and the hydrazide ligands are coordinated to the V(IV) center. The free hydrazide ligands 11-20 were inactive against alpha-glucosidase, but the V(IV) complexes showed varying degrees of inhibition, depending on the type of ligand. The DPPH-radical-scavenging activities of 1-20 were determined, which indicated that steric and/or electronic effects responsible for changes in geometry play important roles in terms of antioxidant potential.
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PMID:Synthesis, spectroscopy, and biological properties of vanadium(IV)-hydrazide complexes. 1820 28