Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The urease and the beta-glucosidase for the identification of the mycobacteria were evaluated using 1,019 strains received for reference purposes in this laboratory in 1978. We found that the urease test was useful in the differential identification of BCG which, contrary to Mycobacterium bovis, gave a strong positive reaction in 3 h. The test was also useful to discriminate M. scrofulaceum from pigmented strains of M. avium. The beta-glucosidase test discriminated between M. tuberculosis and M. bovis and was useful to distinguish the niacine-positive strains of M. africanum which were usually negative in this test. The beta-glucosidase test was particularly useful in the differential identification of M. fortuitum and M. chelonei. In this report, the frequency distribution of the species which were submitted to this laboratory in 1978 was also shown and the results obtained for each of the conventional test procedures was presented.
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PMID:[Evaluation of urease and beta-glucosidase activity for the practical identification of mycobacteria (author's transl)]. 11 59

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

We studied the effect on fecal hydrolytic activities of adopting an uncooked extreme vegan diet and readopting a conventional diet. Eighteen subjects were randomly divided into test and control groups. In the test group subjects adopted the uncooked extreme vegan diet for 1 mo and then resumed a conventional diet for a second month. Controls consumed a conventional diet throughout the study. Phenol and p-cresol concentrations in serum and daily output in urine and fecal enzyme activities were measured. The activity of fecal urease significantly decreased (by 66%) as did cholylglycine hydrolase (55%), beta-glucuronidase (33%) and beta-glucosidase (40%) within 1 wk of beginning the vegan diet. The new level remained throughout the period of consuming this diet. Phenol and p-cresol concentrations in serum and daily outputs in urine significantly declined. The fecal enzyme activities returned to normal values within 2 wk of resuming the conventional diet. Concentrations of phenol and p-cresol in serum and daily output in urine had returned to normal after 1 mo of consuming the conventional diet. No changes were observed in the control group during the study. Results suggest that this uncooked extreme vegan diet causes a decrease in bacterial enzymes and certain toxic products that have been implicated in colon cancer risk.
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PMID:Shifting from a conventional diet to an uncooked vegan diet reversibly alters fecal hydrolytic activities in humans. 155 66

Hyperammonemia interferes with normal brain function. The effect of ammonia on free and membrane-bound lysosomal enzymes and on mucopolysaccharide metabolism was studied in cultured rat brain cells (ROC-1, hybridoma between C6-astrocytoma and oligodendrocytes). Intralysosomal ammoniagenesis was achieved from urea by endocytosed Jackbean urease followed by incubation of the cultures with urea. The intralysosomal location of urease was evidenced by the protective effects of leupeptin and urea on the stability of intracellular urease. Ammonia formed from urea resulted in an increased secretion of lysosomal arylsulfatase-A (AS-A), but not of the membrane-bound lysosomal beta-glucosidase into the culture medium, thus intralysosomal AS-A activity decreased. Lysosomal, membrane-bound beta-glucosidase activity increased, presumably due to intralysosomal proteolytic protection following an increased lysosomal pH. Intralysosomal ammoniagenesis temporarily impaired 35SO4-glycosaminoglycan degradation of prelabeled cells. The results support the hypothesis that hyperammonemic states may interfere with lysosomal functions in vivo as well in cultured cells.
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PMID:Intralysosomal generation of ammonia from urea by endocytosed urease results in secretion of free lysosomal arylsulfatase-A and increased activity of membrane-bound beta-glucosidase in cultured brain cells. 168 84

Weanling or adult (9 wk old) rats were fed diets containing 0, 250 or 500 g lactose/kg for 10 days, after which the activities of six caecal microbial enzymes (azoreductase, beta-glucosidase, beta-glucuronidase, nitrate reductase, nitroreductase and urease) were determined. Adult controls had larger caeca than weanlings, but the numbers of bacteria were not significantly different. Expressed in relation to body weight, caecal microbial enzyme activities were significantly lower in adult controls, with the exceptions of beta-glucuronidase and urease. Lactose caused caecal enlargement; this was greatest in weanling animals, which also showed a decreased concentration of bacteria. Lactose increased total nitrate reductase and urease activities in both age groups, but decreased total azoreductase and nitroreductase activities in weanlings. Enzyme activities per 10(9) bacteria were decreased for azoreductase, beta-glucosidase, beta-glucuronidase and nitroreductase in both age groups, while urease activity increased. Azoreductase and nitroreductase activities were highly correlated but nitrate reductase and urease did not correlate significantly with any other enzyme activity.
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PMID:Dietary lactose and the metabolic activity of the caecal microfloras of weanling and adult rats. 642 83

Agar, carboxymethylcellulose, carrageenan, guar gum, gum acacia, locust-beam gum or pectin (50 g/kg diet), given to weanling rats for 4 wk, increased the weight of the caecal wall and the caecal contents. Feeding carboxymethylcellulose, guar gum or pectin significantly increased, and feeding carrageenan decreased, the total bacterial population of the caecum. Feeding carboxymethylcellulose significantly increased in vitro activity of bacterial azoreductase, beta-glucosidase, beta-glucuronidase, nitrate reductase, nitroreductase and urease. Guar gum, gum acacia and locust-bean gum each increased at least three of these activities. In contrast, feeding carrageenan greatly decreased all microbial enzyme activities, while agar decreased beta-glucosidase, beta-glucuronidase and nitroreductase activities.
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PMID:Hydrocolloid food additives and rat caecal microbial enzyme activities. 653 30

Weanling rats were fed low-fat (1% w/w safflower oil) or high-fat (1% w/w safflower oil plus 35% w/w beef fat or cocoa butter) diets for 30 days, and the activities of five cecal microbial enzymes were determined. When compared with the low-fat diet, beef fat significantly increased total cecal beta-glucuronidase activity, but cocoa butter, with a similar fatty acid composition, did not. Both high-fat diets significantly decreased total cecal azoreductase, beta-glucosidase, and nitrate reductase activities, but neither significantly affected urease activity. When expressed as specific activities (per 10(11) bacteria), cocoa butter decreased azoreductase, and beef fat caused increases of beta-glucuronidase and urease. Beef fat, but not cocoa butter, significantly reduced cecal bacterial numbers when compared to the low-fat diet. Both high-fat diets led to equivalent reductions in the proportion of aerobic bacteria.
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PMID:Dietary fat and cecal microbial activity in the rat. 654 72

The API STAPH-IDENT system was compared with conventional methods for the identification of 14 Staphylococcus species. Conventional methods included the Kloos and Schleifer simplified scheme and DNA-DNA hybridization. The API STAPH-IDENT strip utilizes a battery of 10 miniaturized biochemical tests, including alkaline phosphatase, urease, beta-glucosidase, beta-glucuronidase, and beta-galactosidase activity, aerobic acid formation from D-(+)-mannose, D-mannitol, D-(+)-trehalose, and salicin, and utilization of arginine. Reactions of cultures were determined after 5 h of incubation at 35 degrees C. Results indicated a high degree of congruence (greater than 90%) between the expedient API system and conventional methods for most species. The addition of a test for novobiocin susceptibility to the API system increased the accuracy of identification of S. saprophyticus, S. cohnii, and S. hominis, significantly. Several strains of S. hominis, S. haemolyticus, and S. warneri which were difficult to separate with the Kloos and Schleifer simplified scheme were accurately resolved by the API system.
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PMID:Identification of Staphylococcus species with the API STAPH-IDENT system. 675 90

Adult rats were fed diets containing 0, 25, 50, 100, 200, or 400 g lactalbumin/kg diet for 10 days, and the activities of six cecal microbial enzymes were determined. Total activity per cecum of azoreductase, beta-glucosidase, and urease increased significantly with increasing dietary protein, whereas the activities of beta-glucuronidase and nitroreductase were not significantly affected. Nitrate reductase activity decreased significantly. Total numbers of cecal bacteria were not significantly altered by the treatment.
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PMID:Dietary protein and cecal microbial metabolism in the rat. 687 47

Activities of twelve hydrolytic enzymes in the digestive tract of young rabbits before weaning (4 weeks old) and adult rabbits (3 months old) were measured. The principal digestive enzymes in both groups of rabbits appeared to be amylase (EC 3.2.1.1), maltase (EC 3.2.1.20), pectinase (EC 3.2.1.15) and proteinases. The stomach of young rabbits contained most of the lipolytic activity and 45.7% of the total proteolytic activity of the digestive tract. The highest specific activities (per g digesta) of amylase, maltase and proteinase in young rabbits were found in the small intestine. Total activities (per segment) of amylase and maltase in the small intestine and the caecum were similar. Activities of cellulase (EC 3.2.1.4), inulinase (EC 3.2.1.7) and beta-glucosidase (EC 3.2.1.21) were low and activity of pectinase was fairly high in all segments of the digestive tract. The highest activity of urease (EC 3.5.1.5) was found in the caecum. Enzymic profiles of the colonic chymus resembled those of the caecum. Total hydrolytic activity was lower in the colon than in the caecum. Specific activities of amylase and invertase (EC 3.2.1.26) were lower and those of inulinase and lactase (EC 3.2.1.23) higher in 4-week-old rabbits than in 3-month-old rabbits. Gastric proteinase represented almost half of the total proteolytic activity of the digestive tract, whereas lipolytic activity of gastric contents was not found in measurable quantities in adult rabbits. The caecal contents of adult rabbits contained most of the total activity of lipase (EC 3.1.1.3), cellulase, xylanase (EC 3.2.1.32), pectinase, lactase, invertase, beta-glucosidase and urease present in the digestive tract.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Distribution of activity of hydrolytic enzymes in the digestive tract of rabbits. 753 89


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