Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.7.1.2 (nitrate reductase)
 3,861 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rats, mice, and hamsters were fed a fiber-free purified diet for 30 days and the activity of a number of cecal microbial enzymes was determined. Expressed per gram cecal content, azoreductase activity was greatest in preparations from the hamster and least from the mouse, and beta-glucosidase and beta-glucuronidase activities were least active from the rat. Nitroreductase was less active and nitrate reductase more active from the hamster in comparison to the other species. When expressed per kilogram body weight, bacterial activities were always greatest from the hamster. When the basal diet was supplemented with pectin (50 g/kg diet), nitrate reductase activity was increased six- to sevenfold per gram cecal content for rats and mice (tenfold when expressed per kilogram body weight), but there was no effect on the nitrate reductase activity of hamster microflora. Pectin also significantly increased beta-glucuronidase activity in rats, but significantly reduced the activities of the other enzymes in at least one of the three species.
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PMID:A comparison of the activity of five microbial enzymes in cecal content from rats, mice, and hamsters, and response to dietary pectin. 630 41

Alpha-cellulose, added to a purified diet at six levels [0%, 2.5%, 5%, 10%, 20%, and 40% (w/w)] and fed to weanling rats for 3 weeks, had no effect on body weight, but it increased the weight of caecal contents and decreased the numbers of bacteria per total caecal contents. Caecal microbial azoreductase, nitroreductase, beta-glucosidase and nitrate reductase activities per total caecal contents were also significantly decreased by 10% dietary cellulose and above, yet beta-glucuronidase activity was only affected significantly by 40% dietary cellulose. Azoreductase and nitroreductase activities were highly correlated with one another and showed a similar response to cellulose.
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PMID:Effect of dietary cellulose on the metabolic activity of the rat caecal microflora. 630 19

The enzyme activity of the rat hindgut microflora maintained in an anaerobic two-stage continuous culture was compared with that of rat cecal contents. A qualitative comparison (API ZYM) showed a high degree of similarity between the two populations. Quantitative determinations showed that azoreductase, beta-glucosidase, nitrate reductase, and nitroreductase activities were comparable, and that beta-glucuronidase activity was very low in the culture. beta-Glucuronidase, beta-glucosidase, and nitrate reductase activities were induced within the culture by their respective substrates. Bile acids influenced microbial activity in vitro, with cholic acid inducing beta-glucosidase, azoreductase, and beta-glucuronidase activities and decreasing nitrate reductase activity. Chenodeoxycholic acid increased beta-glucosidase and beta-glucuronidase activities and decreased azoreductase, nitrate reductase, and nitroreductase activities in vitro. These studies demonstrate that the rat hindgut microflora may be successfully cultured in vitro and suggest control mechanisms that regulate the metabolic activity of these organisms in vivo.
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PMID:Metabolic activity and enzyme induction in rat fecal microflora maintained in continuous culture. 641 66

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

Mycobacterium fortuitum and Mycobacterium chelonei are distinguished unambiguously by the combined use of five test characters: nitrate reductase, beta-glucosidase, acid production from fructose, penicillinase, and trehalase. Typically, M. fortuitum was nitrate reductase positive, beta-glucosidase positive; M. chelonei was nitrate reductase negative, beta-glucosidase negative, penicillinase positive, and trehalase positive and did not produce acid from fructose.
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PMID:Differential identification of Mycobacterium fortuitum and Mycobacterium chelonei. 678 Jun 4

Whole cells of Mycobacterium avium, characterized by their negative response in the nine biochemical tests used for mycobacterial identification in our laboratory, turned positive for nitrate reductase, Tween-80 hydrolysis, beta-glucosidase, acid phosphatase, alkaline phosphatase, penicillinase, and trehalase after their wall portion was removed to yield spheroplasts. This suggested that the negative results in most of the biochemical procedures were caused by the exclusion mechanism at the wall level. Preliminary transmission and scanning electron microscopic studies showed differences at wall level between laboratory-maintained opaque, dome-shaped (SmD) and host-recycled smooth, transparent (SmT) colony type variants of M. avium and suggested the presence of an outer regularly structured layer in SmT variants. Comparative ultrastructural studies utilizing different polysaccharide coloration methods confirmed the presence of an outer polysaccharide layer in SmT variants which was probably related to their enhanced pathogenicity for experimental animals and drug resistance as compared to that of SmD variants. These findings are discussed with respect to multiple drug resistance, virulence, and gene expression of M. avium.
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PMID:Multiple drug resistance in Mycobacterium avium: is the wall architecture responsible for exclusion of antimicrobial agents? 679 25

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

The effect on various caecal bacteria and their metabolic activities of feeding diet containing transgalactosylated oligosaccharides (TOS) with or without Bifidobacterium breve (administered in the drinking water) was investigated in rats colonized with a human faecal microflora. TOS (5% w/w in diet) or TOS plus B. breve, given for 4 weeks, induced increases in caecal concentration of total anaerobic bacteria, lactobacilli and bifidobacteria, and decreases in numbers of enterobacteria. Caecal pH was significantly reduced by feeding TOS, as were the activities of beta-glucuronidase and nitrate reductase. In contrast, beta-glucosidase activity was increased in TOS-fed rats. Dietary TOS was also associated with decreased conversion, by caecal contents, of the dietary carcinogen 2-amino-3-methyl-3H-imidazo[4,5-f] quinoline (IQ) to its genotoxic 7-hydroxy derivative.
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PMID:The effects of transgalactosylated oligosaccharides on gut flora metabolism in rats associated with a human faecal microflora. 834 28


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