Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.21 (beta-glucosidase)
3,280 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The beta-glucosidase encoded by the bglA gene from Bacillus polymyxa was overproduced in Escherichia coli by using a plasmid in which bglA is under control of the lacI promoter. Induction with isopropyl-beta-D-thiogalactopyranoside allowed an increase in the specific activity of the enzyme of about 100 times the basal level of gene expression. The enzyme was purified by a two-step procedure involving salting out with ammonium sulfate and ion-exchange chromatography with DEAE-cellulose. Fractions of beta-glucosidase activity recovered by this procedure, after electrophoresis in an acrylamide gel and staining with silver nitrate, yielded a single band of protein. This band was shown by a zymogram to correspond to beta-glucosidase activity. The purified protein showed an apparent molecular mass of 50 kDa and an isoelectric point of 4.6, values in agreement with those expected from the nucleotide sequence of the gene. Km values of the enzyme, with either cellobiose or p-nitrophenyl-beta-D-glucoside as the substrate, were determined. It was shown that the enzyme is competitively inhibited by glucose. The effects of different metallic ions and other agents were studied. Hg2+ was strongly inhibitory, while none of the other cations tested had any significant effect. Ethanol did not show the stimulating effect observed with other beta-glucosidases. The mechanism of enzyme action was investigated. High-pressure liquid chromatography analysis with cellobiose as the substrate confirmed previous data revealing the formation of two products, glucose and another, unidentified, compound. Results presented here indicate that this compound is cellotriose formed by transglycosylation.
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PMID:Purification and characterization of a Bacillus polymyxa beta-glucosidase expressed in Escherichia coli. 156 36

The activities of three bacterial biotransformation enzymes (beta-glucuronidase, beta-glucosidase, nitrate reductase) were determined in suspensions of rat caecal contents or human faeces over the pH range 6-8. All three enzymes were influenced by pH, as exemplified by beta-glucosidase activity which diminished as pH increased. In other instances the rat and human flora showed distinct profiles, with nitrate reductase activity undetectable in human faeces below pH 6.6, whereas the rat caecal flora displayed optimal reduction of nitrate around neutrality. The most pronounced host-species difference was found with beta-glucuronidase, which showed maximal activity at pH 6.0 in human faecal bacteria, while the rat caecal flora expressed greatest activity at pH 8.0. All three enzyme activities were associated with that fraction of rat caecal or human faecal material sedimented by centrifugation at 5000 g for 15 min, with little or no metabolism occurring in the 11,000 g supernatant fluid. The results demonstrate that pH has a pronounced effect on the enzymic activity of bacterial preparations from rat and human sources.
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PMID:The influence of incubation pH on the activity of rat and human gut flora enzymes. 250 31

For 30 days, male weanling rats were fed a semipurified, fiber-free diet or a diet that contained 5, 15, or 30% (wt/wt) wheat bran. The activities of four cecal microbial enzymes were determined. Wheat bran significantly increased the wet weight content of the cecum and total bacterial count per cecum at the intermediate- and high-treatment levels, but it had no effect on bacterial concentration per gram wet weight of cecal contents. Total beta-glucosidase and beta-glucuronidase activities per cecum were generally increased. Wheat bran decreased total nitrate reductase activity, but there was no change in total nitroreductase activity. Wheat bran significantly decreased enzyme activities for nitro-and nitrate reduction per gram of cecal contents but increased beta-glucosidase activity. The activities of the enzymes per 10(11) bacteria followed a similar pattern to that noted per gram of cecal contents. Such fiber-dependent changes in enzyme activity may alter the steady-state concentration of toxic and genotoxic chemicals in the lumen of the hindgut.
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PMID:Influence of wheat bran on some reductive and hydrolytic activities of the rat cecal flora. 301 Feb 50

1. The activities of beta-galactosidase, beta-glucosidase, beta-glucuronidase and N-acetyl, beta-glucosaminidase were estimated in normal and pathological rat urine, with 4-methylumbelliferyl glycosides as substrates. 2. Kidney damage induced by injections of uranium nitrate, mercuric chloride, potassium dichromate or 4-nitrophenylarsonic acid causes a marked increase in the urinary excretion of all four enzymes. 3. The rise in beta-glucosidase activity was associated with the appearance of a new urinary enzyme species, which was examined by starch-gel electrophoresis, DEAE-cellulose chromatography and filtration on Sephadex G-75 and G-200. 4. This enzyme appears to be identical with its counterpart in the kidney, and it is suggested that it arises in the urine as a result of renal tubular breakdown. 5. The other glycosidases examined also show some physical similarities to the corresponding enzymes of the rat kidney.
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PMID:Rat-urine glycosidases and kidney damage. 602 12

The production of the extracellular cellulolytic enzyme system (endoglucanase, exoglucanase and cellobiase) of N. catalinensis was tested with different nitrogen sources, inorganic and organic ones, in liquid culture medium with microcrystalline cellulose. The nitrogen compounds used were: potassium nitrate, sodium nitrate, ammonium nitrate, ammonium phosphate, ammonium sulphate, ammonium chloride, ammonium carbonate, ammonium acetate, ammonium tartrate, urea, casamino acids, glycine, L-alanine, L-leucine, L-proline, L-lysine, L-aspartic acid, L-glutamic acid, L-asparagine, L-glutamine, L-phenylalanine, L-tyrosine, L-tryptophan, L-methionine and L-cysteine. Among these, ammonium nitrate and ammonium tartrate gave the highest yields of cellulases in 20-day-old cultures at a concentration equivalent to 0.75 g N/l in both cases. Optimal temperature for cellulase production, growth and cellulose degradation was 23 degrees C. On the other hand, an initial pH of 6.5 gave the highest yields of endoglucanase and cellobiase. In the same way, at pH 6.5, maximal growth and cellulose degradation were achieved. However, maximal exoglucanase production and glycogen content were reached at pH 7.5.
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PMID:Influence of different cultural conditions on cellulase production by Nectria catalinensis. 962 4

Information on the structure of bacterioplankton communities is continuously increasing, while knowledge of their metabolic capabilities remains limited. In this study, the metabolic capacity of bacterioplankton was investigated, as such information is necessary to fully understand carbon cycling and other biogeochemical processes. The diversity of dominant culturable chemoorganotrophic bacteria from one estuarine and three marine environments was analyzed by random isolation of colony-forming units on solid media, taxonomical identification by partial 16S rRNA gene sequence analysis, and functional characterization of the isolates. A total of 76 16S rRNA gene sequences, representing 19 different genotypes, were obtained from the four sampling localities, including Bacillus, Pseudomonas, Pseudoalteromonas, Vibrio, and Erythrobacter as the most frequently isolated genera. The range of metabolic functions possessed by the cultured bacterial assemblages differed significantly between sites. Similarly, the percentage at each sampling station of bacteria capable of performing a specific function was significantly different for 18 of the 25 investigated metabolic functions. At two localities, the bacterial assemblages were dominated by a single genus (Pseudoalteromonas or Erythrobacter) and appeared to be functionally specialized. More than 95% of the isolates were capable of utilizing dissolved free amino acids and protein as their sole nitrogen sources, and all isolates of the specialized assemblages expressed beta-glucosidase. Furthermore, only some of the isolates were able to utilize NH4+, while up to two thirds of the isolates of the two marine sites were able to grow on NO3-.
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PMID:Functional characteristics of culturable bacterioplankton from marine and estuarine environments. 1549 37

Temporal oscillations in hydrology are a common occurrence in wetlands and can result in alternating flooded and drained conditions in the surface soil. These oscillations in water levels can stimulate microbial activities and result in the mobilization and redistribution of significant amounts of carbon (C), nitrogen (N), and phosphorus (P). The goal of this study was to experimentally simulate a drawdown and reflood of marsh soil from a nutrient-enriched site and a reference site of a wetland (Blue Cypress Marsh Conservation Area, Florida). The goal was to better understand the changes in biogeochemistry and microbial activities present in these soils as a result of hydrological fluctuations. Measurements of dissolved reactive phosphorus (DRP), ammonia, and nitrate in the floodwater indicated significantly higher (alpha = 0.05) NH(4)(+) and DRP fluxes from the nutrient-enriched site; floodwaters in the cores from both sites contained significant NO(3)(-) concentrations (9.6 mg N L(-1)), which was rapidly consumed over the core incubation period (30 d). Water level drawdown and reflooding initially stimulated the soil microbial biomass, methanogenic rates, and extracellular enzyme activities (acid phosphatase and beta-glucosidase). The anaerobic microbial metabolic activities (CO(2)) where initially significantly (alpha = 0.05) enhanced by the reflood, resulting in roughly equivalent rates as the aerobic respiratory activities (CO(2)), presumably as a function of the high water column NO(3)(-) levels. This study illustrates that the reflood event in the hydrological cycles in a wetland can significantly stimulate the activities of hydrolytic enzymes and microbiological communities in these soils.
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PMID:Response of biogeochemical indicators to a drawdown and subsequent reflood. 1553 59

Since the indiscriminate disposal of pig slurry can cause not only air pollution and bad odours but also nutrient pollution of ground waters and superficial waters, composting is sometimes used as one environmentally acceptable method for recycling pig manure. The aim of this study was to evaluate the effect of composting pig slurry on its sanitation (evaluated by ecotoxicity assays and pathogen content determination), as well as to determine the effect of a carbon-rich bulking agent (wood shavings, WS) and the starting C/N ratio on the changes undergone by different chemical (volatile organic matter, C and N fractions) and microbiological (microbial biomass C, ATP, dehydrogenase activity, urease, protease, phosphatase, and beta-glucosidase activities) parameters during composting. Pig slurry mixed with bulking agent (P+WS) and the solid faction separated from it, both with (PSF+WS) and without bulking agent (PSF), were composted for 13 weeks. Samples for analysis were taken from composting piles at the start of the process and at 3, 6, 9, and 13 weeks after the beginning of composting. The total organic carbon, water soluble C and ammonium content decreased with composting, while Kjeldahl N and nitrate content increased. The nitrification process in the PSF+WS pile was more intense than in the PSF or P+WS composting piles. The pathogen content decreased with composting, as did phytotoxic compounds, while the germination index increased with compost age. Piles with bulking agent showed higher values of basal respiration, microbial biomass carbon, ATP and hydrolase activities during the composting process than piles without bulking agent.
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PMID:A full-scale study of treatment of pig slurry by composting: kinetic changes in chemical and microbial properties. 1629 6

The potential impact of different types of organic (sewage sludge) or inorganic (mineral fertilizer) amendments to a basic soil was investigated under dry conditions. A soil incubation experiment was carried out over 64 days; there were two fertility treatments: sewage sludge (SS) (140 t ha(-1)), mineral fertilizer (M) and an unamended control (C). Two levels of irrigation were imposed: (1) well-watered, kept at 60% of its water holding capacity, and (2) water-deficit at 6%. Available N-NO3-, N-NH4+ and P, and electrical conductivity (EC) increased in SS and M-treated soils. Under well-watered conditions activities of some enzymes (protease-BAA, phosphatase and beta-glucosidase), and microbiological properties (microbial biomass carbon, basal respiration and dehydrogenase activity) were stimulated in SS-treated soils. Under water-deficit conditions, protease-BAA, phosphatase and beta-glucosidase activities, and basal respiration were more reduced in SS than in C and M. Results showed that under severe dry conditions, soil microbial activity always remained higher in organic amended soils than when mineral fertilizer was added.
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PMID:Effect of water deficit on microbial characteristics in soil amended with sewage sludge or inorganic fertilizer under laboratory conditions. 1642 75

A Gram-negative, motile, rod-shaped, psychrophilic bacterium, LT17T, was isolated from deep-sea sediments (3300 m depth) of the East Sea (Sea of Japan). Optimal growth of LT17T requires the presence of 2.5 % (w/v) NaCl, a pH of 7.0-7.5 and a temperature of 17 degrees C. The isolate grows optimally under a hydrostatic pressure of 10 MPa and growth is possible between 0.1 and <30 MPa. The novel strain is positive in tests for catalase, oxidase, lipase, beta-glucosidase and gelatinase activities and reduces nitrate to nitrate. The predominant cellular fatty acids are iso-C13 : 0, iso-C15 : 0, C16 : 0, C16 : 1omega7 and C20 : 5omega3. The DNA G+C content of strain LT17T is 38.8 mol%. Phylogenetic analysis of 16S rRNA gene sequences places this bacterium in the class Gammaproteobacteria, within the genus Shewanella. The closest relatives of strain LT17T are Shewanella japonica (97.8 % gene sequence similarity), Shewanella pacifica (97.5 %), Shewanella olleyana (96.8 %), Shewanella frigidimarina (96.5 %) and Shewanella gelidimarina (95.4 %). The DNA-DNA hybridization levels between the novel isolate and its closest known phylogenetic relatives, S. japonica and S. pacifica, are lower than 14 %. On the basis of this polyphasic evidence, strain LT17T represents a novel species of the genus Shewanella, for which the name Shewanella donghaensis sp. nov. is proposed. The type strain is LT17T (=KCTC 10635BPT=JCM 12524T).
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PMID:Shewanella donghaensis sp. nov., a psychrophilic, piezosensitive bacterium producing high levels of polyunsaturated fatty acid, isolated from deep-sea sediments. 1726 51


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