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)

Introduction of anthropogenic chemicals into soil may have lasting effects on soil microbial activities and thus soil health. This study was conducted with chlorothalonil to evaluate its effects on soil bacterial, fungal, and actinomycete populations and soil enzymes (acid phosphatase, alkaline phosphatase, urease, catalase, and invertase) after repeated applications. After the first addition of chlorothalonil, the soil bacterial and actinomycete populations were significantly reduced, whereas the population of soil fungi was unchanged. The most marked inhibition on soil microorganisms was observed after the second pesticide addition. However, after initial variations, soil bacteria, fungi, and actinomycetes adapted gradually to chlorothalonil, and the negative effects became transient and weaker following the third and fourth treatments. The inhibitory effect of repeated chlorothalonil applications on soil enzymes followed a similar trend to that on soil microorganisms. Repeated chlorothalonil applications did not result in significant changes in its persistence. Three bacterial strains capable of utilizing chlorothalonil as a sole source of carbon and energy for growth were isolated 21 days after the fourth treatment with chlorothalonil, which indicated that the capability of soil microorganisms for degrading chlorothalonil was formed during the experiment.
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PMID:Responses of soil microorganisms and enzymes to repeated applications of chlorothalonil. 1717 43

This paper studied the effects of no-tillage on the dynamics of invertase, urease and acid phosphatase activities in an aquic brown soil during maize growing season. The results showed that in 0 - 10 cm soil layer, the invertase activity at jointing, trumpet-shaped and ripening stages, urease activity at jointing and booting stages, and acid phosphatase activity at booting and ripening stages were significantly higher under no-tillage (NT) than under conventional tillage (CT). In 10 - 20 cm soil layer, the invertase activity at seedling, jointing and trumpet-shaped stages was significantly different between NT and CT, and the urease activity during whole growing season except at booting stage was significantly higher under NT than under CT. In 20 - 30 cm soil layer, the invertase activity during maize growing season was significantly lower under NT than under CT, and urease activity at seedling stage and acid phosphate activity at ripening stage were significantly different between these two treatments. Under NT, there was a decreasing trend of soil enzyme activities with increasing soil depth; while under CT, soil invertase and acid phosphatase activities increased, but urease activity decreased with increasing soil depth.
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PMID:[Dynamics of aquic brown soil enzyme activities under no-tillage]. 1733 Apr 78

With adjacent semi-moving dune as the control, this paper studied the effects of 5-, 10- and 22-year old Hedysarum fruticosum plantations on the nutrient status, microbial biomass, and enzyme activities at the soil depths 0-10, 10-20 and 20-30 cm. The results showed that with the establishment of H. fruticosum plantation on moving dune, soil C, N, P and K contents and biological activities increased obviously with the increasing age of the plantation, and the increment was much higher at 0-10 cm than at 10-20 and 20-30 cm. At 0-30 cm, soil C/N increased from 7.3 to 8.5, and microbial biomass C, N and P as well as the activities of urease, protease, saccharase, phosphomonoesterase, dehydrogenase, polyphenol oxidase and nitrate reductase all increased. Among the test enzyme activities, saccharase activity had the most significant increase, with its value at 0-10 cm being 49.7-284.5 times of the control. There were significant positive correlations between soil microbial biomass C, N and P and organic C, total N and total P, respectively, and between soil microbial biomass and enzyme activities.
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PMID:[Amelioration effect of sand-fixing Hedysarum fruticosum plantations on soil nutrient contents and biological activities]. 1797 38

Oyster shell, a byproduct of shellfish-farming in Korea and containing a high amount of CaCO(3), has a high potential to be used as a liming material in agriculture. However, the agricultural utilization of oyster shell is limited due to its high concentration NaCl. The oyster-shell meal collected had a low concentration of water soluble NaCl (mean 2.7 g kg(-1)), which might be a result of stacking the material for 6 months in the open field. It has a very similar liming potential with calcium carbonate, with 3.4 and 3.8 Mg ha(-1) for silt loam (SiL, pH 6.2) and sandy loam (SL, pH 5.8) to bring the soil pH to 6.5, respectively. To determine the effect of crushed oyster-shell meal on improving soil chemical and biological properties and crop plant productivity, oyster-shell meal was applied at rates of 0, 4, 8, 12, and 16 Mg ha(-1) before transplanting Chinese cabbage (Brassica campestris L.) in the two soils mentioned above. Soil pH was significantly increased to 6.9 and 7.4 by 16 Mg ha(-1) shell meal application (4 times higher level than the recommendation) in SiL and SL, respectively, at harvesting stage. The effect of liming was found higher in SL compared to SiL soil, probably due to the different buffering capacity of the two soils. The concentration of NaCl and EC value of soils were found slightly increased with shell meal applications, but no salt damage was observed. Oyster-shell meal application increased soil organic matter, available P, and exchangeable cations concentrations. The improved soil pH and nutrient status significantly increased the microbial biomass C and N concentrations and stimulated soil enzyme activities. With the exception of acid phosphomonoesterase (PMEase) activity, which decreased with increasing soil pH in SL but slightly increased in SiL, the activities of urease and alkali PMEase increased markedly with increasing soil pH by shell meal application. The improved soil chemical and biological properties resulted in increased crop productivity. The highest yield in Chinese cabbage was achieved following the application of 8 Mg ha(-1) oyster-shell meal. Conclusively, crushed oyster shell could be used as an alternative liming material to restore the soil chemical and microbial properties in upland soil and to increase crop productivity.
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PMID:Effects of oyster shell on soil chemical and biological properties and cabbage productivity as a liming materials. 1829 33

A greenhouse pot experiment was conducted to evaluate the effect of sewage sludge (SS), of sugar beet sludge (SBS), or of a combination of both, in the remediation of a highly acidic (pH 3.6) metal-contaminated soil, affected by mining activities. The SS was applied at 100 and 200 Mg ha(-1) (dry weight basis), and the SBS at 7 Mg ha(-1). All pots were sown with Italian ryegrass (Lolium multiflorum Lam.). After 60 d of growth, shoot biomass was quantified and analysed for Cu, Pb and Zn. The pseudo-total and bioavailable contents of Cu, Pb and Zn and the enzymatic activities of beta-glucosidase, acid phosphatase, cellulase, protease and urease were determined in the soil mixtures. Two indirect acute bioassays with leachates from the soil (luminescent inhibition of Vibrio fischeri and Daphnia magna immobilization) were also used. The SS, in particular when in combination with SBS, corrected soil acidity, while increasing the total organic matter content and the cation exchange capacity. The application of SS led to a decrease in the level of effective bioavailable metals (extracted by 0.01 M CaCl(2), pH 5.7, without buffer), but caused an increase in their potential bioavailability (extracted by a solution of 0.5M NH(4)CH(3)COO, 0.5 M CH(3)COOH and 0.01 M EDTA, pH 4.7). Plant biomass increased more than 10 times in the presence of 100 Mg SS ha(-1), and more than five times with the combined use of 100 Mg SS ha(-1) and SBS, but a considerable phytotoxic effect was observed for the application rate of 200 Mg SS ha(-1). Copper, Pb and Zn concentrations in the shoots of L. multiflorum decreased significantly when using 100 Mg SS ha(-1) or SBS. The activities of beta-glucosidase, urease and protease increased with increasing SS applications rates, but cellulase had a reduced activity when using 200 Mg ha(-1)SS. Both amendments were able to suppress soil toxicity to levels that did not affect D. magna, but increased the soil leachate toxicity towards V. fischeri, especially with the application of 200 Mg SS ha(-1). This study showed that for this type of mine soils, and when using SS of similar composition, the maximum SS application rate should be 100 Mg ha(-1), and that liming the SS amended soil with SBS did not contribute to a further improvement in soil quality.
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PMID:Assessment of chemical, biochemical and ecotoxicological aspects in a mine soil amended with sludge of either urban or industrial origin. 1854 5

Studies have shown that physical and chemical properties of soils may be significantly changed when they are subjected to long-term reclaimed water irrigation. It remains unclear how reclaimed water application may affect nutrient cycling in soils. Soil enzymes are responsible for the biogeochemical cycling of many elements and are more sensitive indicators of the ecological changes. In this study, 17 soil enzymes, including those associated with the C, N, P, and S cycles and two oxidoreductases (catalase and dehydrogenase), were assayed in soils obtained from five long-term reclaimed wastewater irrigation sites in southern California. The soil enzyme activities varied widely among the sampling sites. Compared with their respective controls, the overall activities of enzymes involved in the cycling of the four elements in soil were enhanced by an average of 2.2- to 3.1-fold. Principal component analysis and cluster analysis indicated that the soil microbial functional diversity may be evaluated based on activities of catalase, alkaline phosphatase, acid phosphatase, dehydrogenase, and urease.
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PMID:Soil enzyme activities of long-term reclaimed wastewater-irrigated soils. 1876 76

With incubation test, the effects of cadmium (Cd) and mercury (Hg) combined pollution on the urease and acid phosphatase activities in marine sediment silty loam soil (S1) and yellowish red soil (S2) were studied. The results indicated that during the whole incubation period, Cd and Hg, whether singly or combined together, had significant inhibitory effects on the urease and phosphatase activities in the two test soils, and the effects increased with their increasing concentration (except for Cd < or =1 mg x kg(-1)). Compared with that under Cd or Hg pollution, the net change rates of soil urease and acid phosphatase activities under the same level Cd and Hg combined pollution were higher than 0, suggesting the synergistic effects of these two heavy metals on the inhibition of soil urease and acid phosphatase activities. In all treatments, the activities of urease and acid phosphatase were higher in S2 than in S1, possibly due to the higher contents of organic matter and clay particle in S2.
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PMID:[Effects of cadmium and mercury combined pollution on soil urease and acid phosphatase activities]. 1897 67

The effects of antimony (Sb) on microbial growth inhibition and activities of soil enzymes were investigated in the present study. Test bacterial species were Escherichia coli, Bacillus subtilis and Streptococcus aureus. Among the microorganisms tested, S. aureus was the most sensitive. The 50% effects on the inhibition of specific growth rate of E. coli, B. subtilis, and, S. aureus were 555, 18.4, and 15.8 mg Sb L(-1), respectively. A silt loam soil was amended with antimony and incubated in a controlled condition. Microbial activities of dehydrogenase, acid phosphatase (P cycle), arylsulfatase (S cycle), beta-glucosidase (C cycle), urease (N cycle), and fluorescein diacetate hydrolase in soil were measured. Activities of urease and dehydrogenase were related with antimony and can be an early indication of antimony contamination. The maximum increase in soil urease activity by antimony was up to 168% after 3d compared with the control. The activities of other four enzymes (acid phosphatase, fluorescein diacetate hydrolase, arylsulfatase and ss-glucosidase) were less affected by antimony. This study suggested that antimony affects nitrogen cycle in soil by changing urease activity under the neutral pH, however, soil enzyme activities may not be a good protocol due to their complex response patterns to antimony pollution.
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PMID:Effect of antimony on the microbial growth and the activities of soil enzymes. 1903 1

Sewage sludge (SS), municipal solid waste compost, and garden waste compost (GWC) were used as immobilizing agents in aided phytostabilization of an acid metal-contaminated soil affected by mining activities. The organic residues were applied at 25, 50 and 100 Mg ha(-1) (dry weight basis) and perennial ryegrass (Lolium perenne L.) was used as a "green cover". We studied the effects of the treatments on soil phytotoxicity and enzymatic activities, and on the composition and toxicity of the soil leachate towards Vibrio fischeri and Daphnia magna. Application of SS led to the greatest values of dehydrogenase, acid phosphatase, beta-glucosidase, protease and urease activities, corresponding to the greatest overall microbial and biochemical activity in amended soils. Conversely, GWC did not increase these enzymatic activities, relative to the unamended soil, or enhance ryegrass growth. Cellulase activity increased with increasing application rates of the amendments tested, but decreased at the highest SS application rate. The organic amendments were able to suppress soil toxicity to levels that did not affect D. magna, when applied at 50 and 100 Mg ha(-1), but SS, at the same application rates, increased the soil leachate toxicity towards V. fischeri. Moreover, ryegrass showed some phytotoxic symptoms when 100 Mg ha(-1) of SS were applied. This study showed the importance of an integrated evaluation of soil quality on remediation processes. Although SS immobilized trace metals and corrected soil acidity, improving soil biochemical status, when used at high application rates it led to toxicity of soil leachate towards V. fischeri, decreased soil cellulase activity and impaired ryegrass growth.
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PMID:Organic residues as immobilizing agents in aided phytostabilization: (II) effects on soil biochemical and ecotoxicological characteristics. 1909 81

Copper (Cu) is massively used as feed additives in intensive farms, and the discharge and utilization of livestock wastes may cause certain environmental problems. In this paper, a cultivated black soil in Northeast China was sampled, and added with pig manures that contained different concentration of Cu to simulate the vegetable soil under different years of pig manure fertilization. With this soil, a pot experiment was conducted to study the effects of soil Cu accumulation via the application of the pig manures on the aboveground biomass and its Cu concentration of pakchoi (Brassica chinensis L.), soil microbial biomass carbon, and soil enzymes (dehydrogenase, urease, and acid phosphatase) activities. The results showed that pig manure application increased the aboveground biomass of pakchoi significantly, but had no significant effects on the aboveground biomass Cu concentration. Under the application of pig manure, soil dehydrogenase and urease activities increased in a definite period of time, but their activities as well as soil acid phosphatase activity were depressed gradually with the increase of soil Cu concentration. When the soil total Cu concentration reached 301.3 mg x kg(-1), the aboveground biomass of pakchoi, soil microbial biomass carbon, and the activities of dehydrogenase, urease, and acid phosphatase were greatly reducd. The aboveground biomass Cu concentration of pakchoi had significant positive correlations with the concentration of soil total and water soluble Cu (P < 0.01), while the aboveground biomass was negatively correlated with soil total Cu concentration (P < 0.05). It was suggested that the threshold value of Cu in black soil under vegetable cultivation should be less than 301.3 mg x kg(-1).
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PMID:[Risk assessment of pig manure Cu-contamination of black soil in northeast China]. 1928 34


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