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 phosphoglucomutase (PGM)-encoding gene of Bordetella bronchiseptica is required for lipopolysaccharide (LPS) biosynthesis. An insertion mutant of the wild-type B. bronchiseptica strain BB7865 which disrupted LPS biosynthesis was created and characterized (BB7865pgm). Genetic analysis of the mutated gene showed it shares high identity with PGM genes of various bacterial species and forms part of an operon which also encompasses the gene encoding phosphoglucose isomerase. Functional assays for PGM revealed that enzyme activity is expressed in both bvg-positive and bvg-negative strains of B. bronchiseptica and is substantially reduced in BB7865pgm. Complementation of the mutated PGM gene with that from BB7865 restored the wild-type condition for all phenotypes tested. The ability of the mutant BB7865pgm to survive within J774. A1 cells was significantly reduced at 2 h (40% reduction) and 24 h (56% reduction) postinfection. BB7865pgm was also significantly attenuated in its ability to survive in vivo following intranasal infection of mice, being effectively cleared from the lungs within 4 days, whereas the wild-type strain persisted at least 35 days. The activities of superoxide dismutase, urease, and acid phosphatase were unaffected in the PGM-deficient strain. In contrast, the inability to produce wild-type LPS resulted in a reduced bacterial resistance to oxidative stress and a higher susceptibility to the antimicrobial peptide cecropin P.
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PMID:Role of phosphoglucomutase of Bordetella bronchiseptica in lipopolysaccharide biosynthesis and virulence. 1089 72

The influences of Zn and Cu on soil enzyme activities (acid phosphatase, alkaline phosphatase, arylsulfatase, cellulase, dehydrogenase, protease (z-FLase), urease, beta-D-glucosidase and beta-D-fructofuranosidase (invertase)) and microbial biomass carbon were investigated in agricultural soils amended with municipal sewage sludge or compost since 1978. The trace metals in the soils were fractionated using a sequential extraction method. Long-term application of the sewage sludge and composts caused accumulations of Cu and Zn in the soils, ranging from 140 to 144 and from 216 to 292 mg kg(-1), respectively. The percentage of Cu was highest in the NaOH- and HNO3-extractable fractions (44-51% and 38-46%, respectively), while the percentage of Zn was highest in the HNO3- and EDTA-extractable fractions (65-83% and 11-32%, respectively). Although the percentage of the bioavailable fractions (sum of KNO3 + H2O-, NaOH-, and EDTA-extractable amounts) of Cu (53-64%) was higher than that of Zn (15-37%), the percentage of the most labile fractions (KNO3 + H2O) of Zn (2.1-5.9%) was larger than that of Cu (1.1-2.4%). The size of the microbial biomass carbon increased with the application of sewage sludge or compost. For some enzymes, however, the ratio of the enzyme activity to microbial biomass was lower in the soils amended with sewage sludge or compost than that in the control soil. The soil enzyme activities were more adversely affected by Zn than by Cu. From a multiple regression analysis, it was found that dehydrogenase, urease, and beta-D-glucosidase activities were reduced by the KNO3 + H2O-extractable fraction of Zn in the soils. These microbial activities seem to be sensitive to Zn stress, indicating the possibility that they might be useful bioindicators for evaluation of the toxic effects of Zn on microorganisms in the soils.
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PMID:Copper and zinc fractions affecting microorganisms in long-term sludge-amended soils. 1148 Sep 22

The aim of this experiment was the assessment of the influence of various concentrations of H2SeO3 (0.05, 0.5 and 5 mM) on the activity of soil enzymes over 112 days. The lab experiment was performed using soil samples (dust-silt black soil of 1.92% organic C content, pH 7.7), 60% maximal water capacity. The soil samples were treated with a selenic acid water solution at the concentrations mentioned above. As a reference, natural soil was used (without the selenic acid). The activity of the following enzymes was tested: beta-glucosidase, nitrate reductase, urease, dehydrogenase, acid and alkaline phosphatases. The soil was sampled at days 0, 1, 3, 7, 14, 28, 56 and 112. The results of the study have shown that the selenic acid had no effect on the activity of the beta-glucosidase in soil. In the course of the whole experiment, the applied selenic acid inhibited activity of the nitrate reductase up to 70% at 5 mM, and the activity of dehydrogenase was also decreased--by up to 85% at 5 mM, similarly to urease (with the exception of days 14 and 28), and acid phosphatase (until day 56). The activity of alkaline phosphatase was increased by the lowest concentration of selenic acid and decreased by the highest, which was found in the course of the whole experiment. The 5-mM concentration of selenic acid inhibited the activity of all the enzymes tested in this experiment.
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PMID:Influence of various concentrations of selenic acid (IV) on the activity of soil enzymes. 1215 Apr 30

This study demonstrated a general reduction in photosynthesis (carbon fixation, O(2)-evolution and photochemical electron transport chain), the uptake of NH(4)(+), NO(3)(-), urea and PO(4)(3+), and activities of nitrate reductase, urease, acid phosphatase and ATPase following UV-B and copper exposure of Chlorella vulgaris in the absence or presence of 1 and 2 ppm concentrations of a 4-inch-thick ozone layer. Though the effect of stressors used in combination was very detrimental to the above processes, selected concentrations of ozone not only counteracted the UV-B-induced inhibition of the above processes, but also stimulated O(2)-evolution and the photochemical electron transport chain. Kinetics of nutrient uptake and enzyme activities demonstrated that UV-B causes structural change(s) in the enzymes/carriers responsible for the uptake of NH(4)(+), NO(3)(-), urea and PO(4)(3+) as well as their assimilatory enzymes. Except for nitrate reductase, copper was found to compete for the binding sites of all the above enzymes. Synergistic inhibition of photosynthetic activity, nutrient (except NH(4)(+)) uptake, and enzyme activities by UV-B+Cu seems to be due to increased Cu uptake as a consequence of altered membrane permeability brought about by the peroxidation of membrane lipids in UV-B-exposed cells.
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PMID:Interactive effects of UV-B and Cu on photosynthesis, uptake and metabolism of nutrients in a green alga Chlorella vulgaris under simulated ozone column. 1250 15

The reestablishment of autochthonous plant species is an essential strategy for recovering degraded areas under semiarid conditions. A field experiment was carried out to assess the short-term effect of two reafforestation methods involving mycorrhizal inoculation and compost addition on soil quality parameters and Rhamnus lycioides seedling growth. The nutrient content (NPK) and enzymatic activities (dehydrogenase, urease, protease-BAA, acid phosphatase and beta-glucosidase) increased and bulk density decreased in the rhizosphere soil with the organic amendment. Biomass C of rhizosphere soil increased by at least 240% with respect to the control soil after mycorrhizal inoculation and the combination of compost addition + mycorrhizal inoculation. Both mycorrhizal inoculation and composted organic residue addition increased R. lycioides seedling growth in the same proportion. In the short term, we conclude that the application of both reafforestation methods not only enhances the establishment of R. lycioides seedlings, but also improves soil quality.
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PMID:Alteration in rhizosphere soil properties of afforested Rhamnus lycioides seedlings in short-term response to mycorrhizal inoculation with Glomus intraradices and organic amendment. 1259 56

Studies on the enzyme activities and heavy metal contents in soils polluted by abandoned copper tailings showed that the contents of heavy metals in contaminated soils were higher than those in no-polluted soils, and the enzyme activities, especially dehydrogenase and urease activities were decreased significantly with increasing contamination. Multivariate regression analysis indicated that soil dehydrogenase activity was very significantly correlated with the combined effect of several heavy metals, and urease, protease or acid phosphatase activity was significantly related to the combined effect of them. The total enzyme activity of soil might be a useful index in management of these highly contaminated soils, and hence, it is feasible to use this index as a primary biochemical parameter to evaluate heavy metals compound pollution.
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PMID:[Enzyme activities in soils contaminated by abandoned copper tailings]. 1499 60

The objective of our study was to assess the response of physical (aggregate stability and bulk density) and biological (enzyme activities and microbial biomass) soil quality indicators to the adoption of agroecological management practices, such as the planting of forage species (forage area) and the rotation of local crops (polycrop area), carried out in a representative tropical pasture on an integrated livestock-crop farm. The pasture system was used as control (pasture area). In all three areas, the values of water-soluble C were higher in the rainy season compared to the dry season. Pasture and forage areas had the highest percentage of stable aggregates in the rainy season, while polycrops developed soils with less stable aggregates. Soil bulk density was lower in the pasture and forage areas than in the polycrop area. In the pasture area, the microbial biomass C values, dehydrogenase, urease, protease-BAA, acid phosphatase, and beta-glucosidase activities were higher than in the forage and polycrop areas, particularly in the dry season. The highest increase in the microbial biomass C in the rainy season, with respect to the dry season, was recorded in the pasture area (about 1.2-fold). In conclusion, the planting of forage species can be considered an effective practice for carrying out sustainable, integrated livestock-crop systems, due to its general maintenance of soil quality, while the adoption of polycrop rotations appears to be less favorable because it decreases soil quality.
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PMID:Changes in physical and biological soil quality indicators in a tropical crop system (Havana, Cuba) in response to different agroecological management practices. 1501 1

A pot experiment was conducted with silty loam Agrodolf as test soil and with transgenic Bt rice and non-Bt rice as test crops to study the effect of transgenic Bt rice planting on soil urease, phophatase, arylsulfatase, invertase, and dehydrogenase activities. The results showed that Bt toxin could be introduced into soil through root exudates of transgenic Bt rice, and its survival amount in soil varied with time. Compared with non-Bt rice treatment, transgenic Bt rice treatment had a significant decrease (2.47%) of soil urease activity and a significant increase (8.91%) of soil acid phosphatase activity, but no significant change in soil arylsulfatase, invertase, and dehydrogenase activities at the 15th day of emergence. At the 30th day of emergence, the transgenic Bt rice treatment still had a significant decrease of soil urease activity (16.36%) and a significant increase of acid phosphatase activity (35.69%), and no change in invertase activity. It also had significant increase in soil arylsulfatase (19.70%) and dehydrogenase activities (16.83%).
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PMID:[Effect of transgenic Bt rice planting on soil enzyme activities]. 1503 30

The main effects of pollutions including acid rain, Cu2+, atrazine and their combined products on the activities of urease, invertin, acid phosphatase and catalase were studied by means of orthogonal test. The results showed that H+ and Cu2+ had significant influence on the activities of four enzymes and the ability of their inhibiting followed the order: H+ > Cu2+. Al3+ and atrazine only had litter effects on the activity of urease and phosphatase, respectively. Furthermore, interaction analysis revealed that Cu2+ -H+ affected on the activity of acid phosphatase significantly and antagonism on invertin and urease, Cu2+ -atrazine only exhibited the synergism on the activity of acid phosphatase. But atrazine-H+ had non-interaction within the investigated concentration range. Among four enzymes, acid phosphatase was the most sensitive one to the contaminations.
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PMID:Effect of organic/inorganic compounds on the enzymes in soil under acid rain stress. 1513 33

The effects of acid rain, Cu2+ and atrazine on the activities of soil urease, invertase and acid phosphatase were studied by means of orthogonal test. The results showed that the inhibition rate was H+ > Cu2+, and atrazine had no significant influence on urease and intertase. Interaction analysis revealed that Cu x atrazine exhibited synergism on soil acid phosphatase activity, Cu x H had antagonism on soil invertase and urease, but atrazine x H had no interaction within the investigated concentration range. Among the three enzymes, soil acid phosphatase was the most sensitive one to the contaminations.
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PMID:[Effect of acid rain, copper, and atrazine on soil hydrolase activity]. 1513 4


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