Urease Enzyme Activity Research Articles

Effect of monospecific and mixed sea-buckthorn (Hippophae rhamnoides) plantations on the structure and activity of soil microbial communities.

This study aims to evaluate the effect of different afforestation models on soil microbial composition in the Loess Plateau in China. In particular, we determined soil physicochemical properties, enzyme activities, and microbial community structures in the top 0 cm to 10 cm soil underneath a pure Hippophae rhamnoides (SS) stand and three mixed stands, namely, H. rhamnoides and Robinia pseucdoacacia (SC), H. rhamnoides and Pinus tabulaeformis (SY), and H. rhamnoides and Platycladus orientalis (SB). Results showed that total organic carbon (TOC), total nitrogen, and ammonium (NH4 +) contents were higher in SY and SB than in SS. The total microbial biomass, bacterial biomass, and Gram+ biomass of the three mixed stands were significantly higher than those of the pure stand. However, no significant difference was found in fungal biomass. Correlation analysis suggested that soil microbial communities are significantly and positively correlated with some chemical parameters of soil, such as TOC, total phosphorus, total potassium, available phosphorus, NH4 + content, nitrate content (NH3 −), and the enzyme activities of urease, peroxidase, and phosphatase. Principal component analysis showed that the microbial community structures of SB and SS could clearly be discriminated from each other and from the others, whereas SY and SC were similar. In conclusion, tree species indirectly but significantly affect soil microbial communities and enzyme activities through soil physicochemical properties. In addition, mixing P. tabulaeformis or P. orientalis in H. rhamnoides plantations is a suitable afforestation model in the Loess Plateau, because of significant positive effects on soil nutrient conditions, microbial community, and enzyme activities over pure plantations.

Effects of AM Fungi and Plant Growth-promoting Rhizobacteria on Enzymatic Activities of Soil under Turmeric (Curcuma longaL.) Cultivation

Rhizomes of turmeric (Curcuma longa L.) are widely used for their medicinal as well as flavoring properties and in order to concentrate on biological means of promoting turmeric cultivation in Assam, a greenhouse experiment was conducted to evaluate the effects of native arbuscular mycorrhizal fungi (Glomus, Gigaspora and Acaulospora sp.) sourced from turmeric rhizosphere along with phosphate solubilizers (Bacillus megaterium) and nitrogen fixers (Azospirillum amazonense and Azotobacter sp.) on soil enzyme activities and microbial characteristics of soil under turmeric cultivation. The single, dual and consortium inoculations showed higher enzyme activities over control. Results revealed an increase in phosphatase (18.3–21.3 μmol p-nitrophenol g−1 h−1), dehydrogenase (83.4–100.5 nmol TPF g−1 h−1) and urease (83.2–99.5 μmol NH3-N g−1 h−1) enzyme activities along with an increase of 1.30–1.82 μg g−1 soil microbial biomass carbon content. Besides, mycorrhizal colonization rate showed a similar pattern in dual and consortium inoculation with single inoculation of arbuscular mycorrhizal fungi (95.2–97%) suggesting the plant growth promoting microbes as mycorrhiza helper bacteria for a clear preference as bioinoculants to be used for a sustainable agricultural strategy.

外来植物火炬树（Rhus typhinaL.）入侵对不同林型土壤性质的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 外来植物火炬树(Rhus typhina L.)入侵对不同林型土壤性质的影响 DOI: 10.5846/stxb201404160740 作者: 作者单位: 鲁东大学生命科学学院,鲁东大学生命科学学院,鲁东大学生命科学学院,鲁东大学生命科学学院,鲁东大学生命科学学院,鲁东大学生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(31300465); 山东省自然科学基金项目(ZR2012CQ020); 山东省高等学校科技计划项目(J13LE08); 烟台市科技发展计划项目(2012124) Effects of exotic plant Rhus typhina invasion on soil properties in different forest types Author: Affiliation: College of Life Sciences,Ludong University,College of Life Sciences,Ludong University,College of Life Sciences,Ludong University,College of Life Sciences,Ludong University,College of Life Sciences,Ludong University,College of Life Sciences,Ludong University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:生物入侵在世界范围内广泛发生,严重威胁当地生物多样性和生态系统稳定性。植物与土壤之间的相互作用在决定植物的竞争力以及分布格局中起着重要作用,是影响外来植物入侵力和生态系统可入侵性的一个重要方面。目前,有关研究已成为植被生态学与入侵生态学的研究热点。引自北美的外来植物火炬树(Rhus typhina L.)已成为我国北方主要的入侵木本植物之一。比较了火炬树单优林型、火炬树+刺槐(Robinia pseudoacacia L.)混交林、火炬树+麻栎(Quercus acutissima Carruth.)混交林、火炬树+银白杨(Populus alba L.)混交林4种不同林型的土壤微生物群落结构、土壤酶活性和土壤养分含量特征。结果表明:火炬树单优林土壤细菌、放线菌数量明显高于各混交林型,而真菌数量无显著差异;土壤酶活性方面,火炬树单优林脲酶、过氧化氢酶活性高,土壤磷酸酶活性低;火炬树的入侵显著提高了土壤全碳、全氮、全磷和硝态氮含量,同时明显降低了土壤铵态氮含量。硝态氮含量的增高可能与火炬树入侵造成土壤微生物群落组成变化、土壤硝化速率高有关;而火炬树入侵降低了土壤铵态氮含量,说明该物种可能更易于吸收利用铵态氮。以上研究结果表明,火炬树可以改变土壤生态系统的微生物群落组成和土壤酶活性并影响土壤相关营养元素循环,从而可能使其在与当地植物的竞争中获得优势,为自身的入侵创造有利条件。 Abstract:Rapid expansion of exotic invasive plants throughout the world is well acknowledged as one of the major threats to biodiversity and ecosystem stability. Plant-soil interactions play an important role in plant competition and distribution, and represent an important aspect of the invasion potential of exotic plants and ecosystem invasibility, one of the hot research topics in vegetation and invasion ecology. Rhus typhina, an exotic large shrub or small tree introduced from North America in 1959, was identified as a main afforestation species in Northern China. However, as its distribution keeps expanding, it has been increasingly realized as a potential invasive species in local habitats. In the present study, we examined the influence of R. typhina invasions in four different forest types on typical soil properties, including soil microbial community, soil enzyme activities, and soil chemical properties. In April 2012, soil samples were collected from four different types of forests (dominated by R. typhina, R. typhina + Robinia pseudoacacia, R. typhina + Quercus acutissima, R. typhina + Populus alba, respectively) in the Zhen Mountain, Yantai of Shandong Province. Subsequently, soil microbial community, soil enzyme activities, and soil chemical properties of each soil sample were analyzed in the laboratory. The results showed that the invasion of the exotic plant R. typhina affected soil properties by (1) significantly increasing the amount of bacteria and actinomyces, but not the fungi; (2) significantly enhancing the soil enzyme activities of urease and catalase, while decreasing acid phosphatase; (3) accelerating the soil total C, total N, total P and nitrate N content, but decreasing the ammonium N content. The elevated nitrate N content may be caused by the altered composition of soil microbial community and the accelerating soil nitrification rate by R. typhina invasion. However, the ammonium N content was reduced after R. typhina invasion, suggesting that R. typhina prefers to absorb and utilize ammonium N in the soil. Collectively, our results strongly suggest that R. typhina can alter soil nutrient dynamics by modifying the composition of soil biota and the activities of soil enzymes, which in turn alter the soil properties. All these changes may endow R. typhina advantages in competition with native species during its establishment, inhibit native plants, and finally facilitate its invasion process in the field. Both management of exotic plant invasions and the restoration of native invaded communities should be sufficient to manage the effects of exotic plant species on the soil. This study has theoretical and practical implications for studying the mechanisms underlying biological invasions and the risk-assessment and management of exotic plant R. typhina respectively. 参考文献 相似文献 引证文献

Study of the Correlation between Helicobacter pylori Infection and Hepatic Encephalopathy in Patients with Liver Cirrhosis

Background and study aim: Ammonia plays a major role in hepatic encephalopathy pathogenesis. Most of ammonia is known to be produced by the action of colonic bacteria which possess a urease enzyme activity. H. pylori which infects the stomach possesses a stronger urease activity which produce a large amount of ammonia that may precipitate hepatic encephalopathy (HE). The aim of the present study is to determine the correlation between Helicobacter pylori infection and HE in patients with liver cirrhosis. Patients and Methods: One hundred patients (50 patients of liver cirrhosis with hepatic encephalopathy and 50 patients of liver cirrhosis without hepatic encephalo-pathy) were evaluated for presence of H. pylori by stool antigen test (ELISA method) and for blood ammonia level estimation. Results: Pevalence of H. pylori infection in the study groups (patients of liver cirrhosis with and without hepatic encephalopathy) was 70% (liver cirrhosis with hepatic encephalopathy group (A) 80%, and liver cirrhosis without hepatic encephalopathy group (B) 60%). Mean blood ammonia levels were: 82.14± 47.9 mmol/l for group A (liver cirrhosis with hepatic encephalopathy) and 36.44± 17.9 mmol/l for group B (liver cirrhosis without hepatic encephalopathy). Prevalence of H. pylori and blood ammonia level were found significantly increasing with the severity and the degree of hepatic encephalopathy. Conclusion: There is a significant association between H. pylori and hepatic encephalopathy in patients with liver cirrhosis. There may be a role of anti-H. pylori therapy in patients of hepatic encephalopathy and should be investigated further.

تأثير تغليف سماد اليوريا بمستخلصات النواتج الثانوية ( فينولات و زيوت طيارة ) من بعض النباتات على تثبيط نشاط أنزيم اليورييز في التربة = Effect of Coating Urea with Some Plant Secondary Products ( Phenolic and Votilized Oils ) on Urease Inhibition in Soil

An experiment was conducted to study the efficiency of coating urea with some secondary metabolism products extracted from plants to inhibit urease enzyme activity in silty loam soil. Phenolic substances and votilized oils were extrected from data palm fiber, eucalyptus leaves and myrtus leaves by applying standard methods.Urea fertilizer was coated with above extracts at ratios: 2.5, 5 and 10% (w/w) .Coated urea was applied to soils at rates of 30,90 and 270 mgN Kg-1soil.Fifty grames of soil were treated with coated urea and incubated at temperature of 37ᴼ C for 5 and 10 days.Then urease enzyme activity was measured and inhibition percentages were calculated. Results showed that coating urea fertilizer with phenolic or votilized oil compouned extracted from data palm fiber, eucalyptus and myrtus leaves reduced urease activity in soil. Highest urease inhibition (avg 63 % ) was obtained in soil treated with urea coated with phenole compouned (at ratio 5%)or votilized oil (at ratio 10%) extracted from eucalyptus leaves at 270 mg N Kg-1soil. Highest urease inhibition in soil treated with urea + ATS (Ammonium thiosulfate) at 270 mg N Kg-1soil was 56% . These results suggested a possibility of using urea coated with Phenolic substances and votilized oils extracted from some plants to reduced urea hydrolysis in soil and could be apotent substitute for ATS to increase urea efficiency.

Effects of the Biocontrol Agent Aspergillus flavipes on the Soil Microflora and Soil Enzymes in the Rooting Zone of Pepper Plants Infected with Phytophthora capsici

AbstractThis study examined the effect of ASD strain (Aspergillus flavipes), isolated from continuous cropping soil for pepper and named by the sampling position, on soil microflora and soil enzymes in rooting zone soil of healthy and diseased (Phytophthora capsici) pepper plants. Results showed that the ASD strain could significantly reduce the number of bacteria and actinomycetes, with a significant increase in fungi in the rhizosphere soil of both healthy and diseased plants. With increasing colonization time of the ASD strain, the number of bacteria and actinomycetes decreased initially and then increased gradually, while the number of fungi was first increased significantly and later decreased slowly. The soil enzyme activities of urease, acid phosphatase, invertase and dehydrogenase were significantly increased by the ASD strain, while the activity of catalase was not significantly increased. As time from inoculation with the ASD strain increased, the activities of various enzymes were higher than controls. Maximum enzyme activities were found on the tenth day after ADS inoculation. The response of soil enzyme activities affected by the ASD strain was as follows: urease > dehydrogenase > invertase > acid phosphatase > catalase. These results suggest that the biocontrol of ASD strain could improve the micro ecology of rhizosphere soil.

Evaluation of the biocontrol potential of Streptomyces goshikiensis YCXU against Fusarium oxysporum f. sp. niveum

A rhizobacterium with broad spectrum antifungal activity was isolated from the rhizosphere of a healthy cucumber plant in a Fusarium wilt diseased field. Phylogenetic tree analysis based on similarity percentage showed that the bacterium was 99% affiliated with the species Streptomyces goshikiensis. The strain, coded as S. goshikiensis YCXU, inhibited in vitro a broad range of phytopathogenic fungi, so it was selected for more detailed characterization. The strain could utilize different carbon sources and exhibited catalase, β-1,3-glucanase, chitinase and urease enzyme activities. The strain showed maximum growth at the pH of 7, temperature of 28°C and NaCl concentration of 1%. The stain was able to produce antifungal diffusible and volatile organic compounds that significantly inhibited the growth of pathogenic fungi. In the greenhouse experiments, watermelon plants fresh and dry weights were significantly increased, and the incidence of Fusarium wilt was decreased by 67% when the strain enriched by a bioorganic fertilizer was applied to both nursery soil and pot soil (NS). The treatment NS also showed 88.9% less pathogen population in soil as compared to control. The use of biocontrol agents decreased the stress indicator enzymes and malondialdehyde content by 55–70% and 62%, respectively as compared to control. The denaturing gradient gel electrophoresis (DGGE) analysis showed significant variations in the fungal and bacterial community structures of all treatments resulted from UPGMA cluster analysis. This study showed that S. goshikiensis YCXU could be a potential biocontrol agent for controlling watermelon Fusarium wilt disease.

Microbial quantities and enzyme activity in soil irrigated with sewage for different lengths of time.

Sewage is widely used on agricultural soils in peri-urban areas of developing countries to meet shortages of water resource. Although sewage is a good source of plant nutrients, it also increases the heavy metals loads to soils. Microbial responses to these contaminants may serve as early warning indicators of adverse effects of sewage irrigation on soil quality. The purpose of this study was to assess the effect of time of sewage irrigation on soil microbial indicators. Soil samples were collected from seven soil sites (S1-S7) irrigated with 0 years, 16 years, 23 years, 25 years, 27 years, 32 years and 52 years, respectively in Shijiazhuang of China and analyzed. For each soil sample, we determined the quantities of bacteria, fungi and actinomycete, and enzyme activities of urease, sucrase, phosphatase, dehydrogenase and catalase. Our results showed that the soils of S2-S7 irrigated with sewage effluents for different times (ranged between 16 and 52 years) exhibited higher densities of bacteria, actinomycete, urease, sucrase and phosphatase but lower densities of fungi when compared with S1 irrigated with sewage effluents for 0 years. The soil S7 irrigated with sewage effluents for longest times (52 years) contained lowest activities of catalase when compared with the soils of S1-S6. The densities of bacteria (R = 0.877, p < 0.01), actinomycete (R = 0.875, p < 0.01), sucrase (R = 0.858, p < 0.01) and phosphatase (R = 0.804, p < 0.05) were significantly correlated in a positive manner with time of sewage irrigation. Soil fungi quantities and urease, dehydrogenase and catalase activities did not change significantly with irrigation time. This study confirms that sewage irrigation had negative effects on microbial properties including fungi, catalase and dehydrogenase in the long term, so there is a need for continuous monitoring for sustainable soil health.

Soil microbiological properties and its stratification ratios for soil quality assessment under different cover crop management systems in a semiarid vineyard

AbstractIn vineyards in Spain, tillage and semiarid Mediterranean climatic conditions accelerate organic matter loss from the soil. Cover crops are a conservation management practice that can provoke changes in soil quality which requires evaluation. Stratification ratios of soil properties such as soil organic C and labile C fractions have been proposed for the assessment of soil quality under different soil management systems. Our objective was to study the effect of different cover crop management on various soil parameters and their stratification ratios. We evaluated three different soil managements in a Typic Haploxerept from NE Spain: conventional tillage (CT); 5‐y continuous cover crop of resident vegetation (RV); and 4‐y continuous cover crop of Festuca longifolia Thuill., followed by 1‐y Bromus catharticus L. after resowing (BV). We monitored soil organic C, particulate organic C, water soluble C, potentially mineralizable N, microbial biomass C, β‐glucosidase and urease enzymatic activities, and water stable aggregates at 0–2.5, 2.5–5, 5–15, 15–25, and 25–45 cm soil depths. We calculated soil depth stratification ratios of those soil properties. Resident cover crop increased microbiological properties, labile C fractions, and aggregation with respect to conventional tillage at 0–2.5 and 2.5–5 cm soil depths. However, for Bromus cover crop the same soil properties were lower than for the resident cover crop at 0–2.5 cm depth. Stratification ratios of β‐glucosidase and urease enzymatic activities, and particulate organic C showed a higher sensitivity than other soil properties; therefore, they would be the best indicators for soil quality assessment in semiarid Mediterranean vineyards.

Nitrogen Utilization and Metabolism in Ruminococcus albus 8

The model rumen Firmicutes organism Ruminococcus albus 8 was grown using ammonia, urea, or peptides as the sole nitrogen source; growth was not observed with amino acids as the sole nitrogen source. Growth of R. albus 8 on ammonia and urea showed the same growth rate (0.08 h(-1)) and similar maximum cell densities (for ammonia, the optical density at 600 nm [OD600] was 1.01; and for urea, the OD600 was 0.99); however, growth on peptides resulted in a nearly identical growth rate (0.09 h(-1)) and a lower maximum cell density (OD600 = 0.58). To identify differences in gene expression and enzyme activities, the transcript abundances of 10 different genes involved in nitrogen metabolism and specific enzyme activities were analyzed by harvesting mRNA and crude protein from cells at the mid- and late exponential phases of growth on the different N sources. Transcript abundances and enzyme activities varied according to nitrogen source, ammonia concentration, and growth phase. Growth of R. albus 8 on ammonia and urea was similar, with the only observed difference being an increase in urease transcript abundance and enzyme activity in urea-grown cultures. Growth of R. albus 8 on peptides showed a different nitrogen metabolism pattern, with higher gene transcript abundance levels of gdhA, glnA, gltB, amtB, glnK, and ureC, as well as higher activities of glutamate dehydrogenase and urease. These results demonstrate that ammonia, urea, and peptides can all serve as nitrogen sources for R. albus and that nitrogen metabolism genes and enzyme activities of R. albus 8 are regulated by nitrogen source and the level of ammonia in the growth medium.

Screening of 20 commonly used Iranian traditional medicinal plants against urease.

Infection with Helicobacter pyloriis the most common cause of stomach and duodenal ulcers. About more than 80 % of people are infected with H. pylori in developing countries. H. pylori uses urease enzyme product "ammonia" in order to neutralize and protect itself from the stomach acidic condition and urease enzyme activity has been shown to be essential to the colonization of H. pylori. Inhibitory activity of 20 traditional medicinal plants were examined and evaluated against Jack bean urease activity by Berthelot reaction to obtains natural sources of urease inhibitors. Each herb was extracted using 80% aqueous methanol, then tested its IC50 value was determined. Eight of the whole 20 studied plants crude extracts were found the most effective with IC50 values of less than 100 μg/mL including Laurus nobilis, Zingiber officinale, Nigella sativa, Angelica archangelica, Acorus calamus, Allium sativum,Curcuma longa, and Citrus aurantium extracts, from which most potent urease inhibitory was observed for Zingiber officinale, Laurus nobilis, and Nigella sativa with IC50 values of 48.54, 48.69 and 59.10 μg/mL, respectively.

不同有机无机肥配施比例对红壤旱地花生产量、土壤速效养分和生物学性质的影响

Low yield of peanut production due to low soil fertility,and environmental pollution as a result of disorderly discharge of animal excretion from large-scale animal farms. Some researchers have proposed application of animal excretions as organic manure into farmlands and hold that it a win-win solution to the problems. However,some scientists have proved that long-term excessive application of pig manure will bring about heavy metal accumulations in the soil and pollution of groundwater with nitrate; and some others have found that application of pig manure,if low in rate,not only increases labor cost but also has little effect on yield. Hence,how to make use of organic manure properly to optimize crops in yield and soil in quality without any risk of environmental pollution has become a pressing issue. For that a filed experiment was carried out at the Yingtan National Agroecosystem Field Experiment Station located in Yujiang County,Jiangxi Province,a subtropical area of China,to tackle this problem. The experiment was designed to have six treatments,i. e. no fertilizer( CK),conventional chemical fertilization( T0),80% chemical fertilizer N plus 20% manure N( T20),60% chemical fertilizer N plus 40% manure N( T40),40% chemical fertilizer N plus 60% manure N( T60),and 20%chemical fertilizer N plus 80% manure N( T80),with a view to exploring effects of application of organic manure,relative to its rate,on yield of peanut,soil available nutrient and biological properties and further-on an optimal combination of chemical fertilizer with organic manure for peanut production in this area. So this study not only has its important theoretical significance in enriching the physiological study on nutrition and quality of peanut,but also possesses some practical meaning in reducing the waste of organic manure resources and alleviating the potential risk of application of organic manure polluting the environment. Results of the field experiment are encouraging.( 1) Combined application had significant effects of improving yield of peanut,the plants in Treatment T40 were the highest in pod yield,kernel yield,pods per plant,per hundred kernel weight,being 20. 14%,26. 92%,27. 87% and 7. 08%,respectively,higher than their respective ones in Treatment T0( 2) combination application of organic and inorganic fertilizer have great influence on the soil available nutrient. After harvesting the peanut,the T40 treatment of the available N,available P and available K increased by 17. 89% 、22. 96% 、12. 57%,respectively as compared with Treatment T0.( 3) Numbers of bacteria,actinomycetes and fungi were raised with the increase of amount combined application of organic and inorganic fertilizer.Compared to the T0,number of the three kind of microorganism were in creased by 71. 62% 、40. 42% 、43. 94%,respectively.( 4) Fertilization can significantly enhance the enzyme activity of urease,invertase,acid phosphatase. The enzyme activity of medium( T40) and high( T60,T80) level of combined application were much higher than that of the other treatments. The effect of low level of combined application( T20) was near to the pure inorganic fertilizer. Based on the above-described findings,it can be concluded that on the condition that equivalent N,P,K nutrients are supplied,the application of fertilizer containing 35% of N in the form of organic manure can not only turn large volumes of animal excretions into organic manure,,but also reduce the use of chemical fertilizer and improve the yield,quality and physiological properties of peanut in red soil areas,which means a great augmentation of economic value and social benefit.

Immunological features and efficacy of a multi-epitope vaccine CTB-UE against H. pylori in BALB/c mice model

Epitope vaccine is a promising option for prophylactic and therapeutic vaccination against Helicobacter pylori infection. Urease is an essential virulence factor and colonization factor for H. pylori. In this study, we constructed a multi-epitope vaccine named CTB-UE with mucosal adjuvant cholera toxin B subunit (CTB) and tandem copies of Th and B cell epitopes from H. pylori urease A and B subunits. The immunogenicity, specificity, ability to induce neutralizing antibodies against H. pylori urease, and prophylactic and therapeutic efficacy of the CTB-UE vaccine were evaluated in BALB/c mice model after purification. The experimental results indicated that CTB-UE could induce comparatively high levels of specific antibodies against native H. pylori urease, UreA, UreB, or the selected B cell epitopes UreA₁₈₃₋₂₀₃ and UreB₃₂₇₋₃₃₄ involved with the active site of urease and showed an effectively inhibitory effect on the enzymatic activity of urease. Besides, oral prophylactic or therapeutic immunization with CTB-UE significantly decreased H. pylori colonization compared with oral immunization with rUreB or PBS, and the protection was correlated with antigen-specific CD4⁺ T cells and IgG, IgA, and mucosal sIgA antibody responses. This CTB-UE vaccine may be a promising vaccine candidate for the control of H. pylori infection.

Effect of Imidacloprid and Triadimefon on microbial phosphatase, protease and urease enzyme activities in tomato (Lycopersicon esculentum sp.) cultivated soil

The laboratory studies were conducted to resolute the effects of Imidacloprid (insecticide) and Triadimefon (fungicide) singly and in combination on enzymatic activities of soil microorganisms in tomato cultivated soils at different concentrations of 0.2, 0.5 and 0.7 kg per hectare. It was observed that phosphatase, protease and urease activities were elevated noteworthy at 0.5kg per hectare after 10 days of incubation. At lower concentration the activities of these enzymes showed no significant difference from that of control. The combination of the two pesticides led to a pronounced decline of phosphatase and protease enzyme activities at higher concentration. Triadimefon had no effect on urease activity at low concentrations whereas at 0.5 and 0.7 concentrations there was a significant increase when compared to control.

Influence of Red Mud-N, P Coated Particles on Micro-Environment in Contaminated Ore Soil

In this research, improved granulation based on partly hydration of red mud was combined with gelling materials. Nitrogen and phosphoric salt were added in during granulation. Soil samples were collected periodically to evaluate the changes of pH, Z-potential and enzymatic activities of urease, catalase and alkaline phosphatase of soil. And the correlations among them were analyzed. Increase of pH that was caused by strong alkali was slowed by applying of composite particles. Dissolved phosphorus greatly inhibited all enzymatic activities while reinforcing restoration.

Effects of microbial inoculations on soil chemical, biochemical and microbial biomass carbon of cassava (Manihot esculenta Crantz) growing Vertisols

Cassava is an important subsidiary food in the tropics. In Tamil Nadu, India, microbial cultures were used to eradicate the tuberous root rot of cassava. Hence, an experiment was conducted for two consecutive years to test the effects of coinoculation of microbes on soil properties. The surface soil from the experimental site was analysed for soil available nutrients, soil enzyme activities and microbial biomass carbon. The treatment of Azospirillum with Trichoderma at the 50% recommended N:P2O5:K2O (NPK) rate (50:25:50 kg ha−1) significantly increased soil available nitrogen (142.81 kg ha−1) by 72.66% over uninoculated control. There was a significant increase in available phosphorus in soil by the inoculation of AM (arbuscular mycorrhizal) fungi with Trichoderma at the 50% recommended NPK rate (41.04 kg ha−1) compared to other treatments. The application of Pseudomonas fluorescens with Trichoderma at the 50% recommended NPK rate significantly increased available iron (19.34 µg g−1) in soil. The treatment of Azospirillum with Trichoderma increased urease enzyme activity at the recommended NPK rate (816.32 μg urea hydrolyzed g−1 soil h−1). Soil application of all cultures at the 50% recommended NPK rate significantly increased dehydrogenase activity (88.63 μg TPF g−1 soil) and β-glucosidase activity (48.82 μg PNP g−1 soil) in soil. Inoculation of Trichoderma alone at the 50% recommended NPK rate significantly increased microbial biomass carbon (3748.85 μg g−1 soil). Thus, the microbial inoculations significantly increased soil available nutrient contents, enzyme activities such as urease, dehydrogenase and β-glucosidase activity and microbial biomass carbon by reducing the amount of the required fertilizer.

Soil microbial mechanisms of Stevia rebaudiana (Bertoni) residue returning increasing crop yield and quality

Due to the ever-increasing worldwide plantation of sweet leaf Stevia rebaudiana (Bertoni), how to efficiently and effectively utilize the huge amounts of leaf residues that contain abundant nutrients after sweetener extraction becomes an eminent issue. One option is to return these residues into soil, as organic manure in the fresh or composted form, in order to both sustain soil fertility and avoid potential environmental pollution. In a field experiment, we studied if the Stevia leaf residue returning affected both plant and soil microbial growths as well as the possible change of soil microbial community composition. In doing so, four treatments were employed: (1) no chemical fertilization and no Stevia residue returning (no-fertilization control); (2) chemical N, P, and K fertilization (NPK); (3) fresh Stevia residue plus NPK (FS + NPK); and (4) composted Stevia residue plus NPK (CS + NPK). Responses of plant and soil microbial communities to Stevia residue input after 1-year fertilizations were investigated by multiple approaches, including soil enzyme assay, real-time quantitative polymerase chain reaction, and PCR–denaturing gradient gel electrophoresis. Our results showed that compared to the sole NPK and no-fertilization control, returning Stevia residues to soil stimulated the enzyme activities of dehydrogenase, invertase, and urease, except neutral phosphomonoesterase; thereby, both the Stevia leaf biomass and sweet glycoside of rebaudioside A were increased. The soil microbial community abundance was increased by the returning of Stevia residues, and their composition was shifted, evidenced by an increase of relative abundance of some genotypic groups, such as Bacillales. Further molecular analysis of Bacillus confirmed that this guild composition was positively influenced by Stevia residue returning, especially for Bacillaceae. Our results demonstrated an effective use of Stevia residues as organic manure for promoting Stevia yield and quality through stimulating soil microbial growth and enzyme activities.

施肥对旱地花生主要土壤肥力指标及产量的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 施肥对旱地花生主要土壤肥力指标及产量的影响 DOI: 10.5846/stxb201204230581 作者: 作者单位: 山东省花生研究所,山东省花生研究所,山东省花生研究所,山东省花生研究所,山东省花生研究所,山东省花生研究所,山东省花生研究所,山东省花生研究所,山东省花生研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 山东省农业重大应用技术创新课题(夏花生高产高效关键技术研究);山东省科技发展计划项目(2012GNC11102);青岛市公共领域科技支撑计划项目( 12-1-3-28-nsh 和11-2-3-28-nsh) Effects of fertilization on soil fertility indices and yield of dry-land peanut Author: Affiliation: Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao,Shandong Peanut Research Institute,Qingdao Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:大田条件下,研究了纯无机肥及不同用量有机-无机配施对旱地砂壤土花生土壤微生物种群及数量、土壤主要酶活性、土壤呼吸速率及产量的影响,结果表明:(1)土壤中细菌、放线菌和真菌数量随有机无机肥配施数量的增加而增加;单施无机复合肥对微生物数量的增加不明显,中量有机无机肥配施比单纯施中量无机肥处理的细菌、放线菌和真菌数量全生育期平均值分别提高114.9%、49.0%和29.0%。(2)施肥可以显著提高土壤脲酶、蔗糖酶、酸性磷酸酶、过氧化氢酶活性及土壤呼吸速率,其中有机无机中、高量配施显著高于其他处理,中量纯无机肥(农民常规施肥)相近于或低于(尤其在生育后期)低量有机无机肥配施;施肥对土壤过氧化氢酶活性的影响小于其余3种酶。(3)不同类群土壤微生物数量、土壤主要酶活性及土壤呼吸作用关系密切,相互间相关系数均达到极显著水平。(4)有机无机中、高量配施花生产量显著高于其他处理,中量无机肥加中量有机肥比中量纯无机肥增产14.0%,表明在砂壤土上施用有机肥,其对土壤肥力提高的增产作用远远大于其本身所含花生生育所需营养直接供应作用。(5)兼顾土壤肥力和花生产量,肥力中等的砂壤土,可采用中量有机无机肥混配施用。 Abstract:Effects of pure inorganic fertilizer and different amounts of compound of organic fertilizer (yard manure) and inorganic fertilization on numbers of soil microbe, soil enzyme activities, soil respiration rate and yield of peanut were studied under field condition. The results were as follows: (1) Numbers of bacteria, actinomycetes and fungi were raised with the increase of amount combined application of organic and inorganic fertilizer. Pure inorganic fertilizer had not obviously effect on the number of soil microbe.Numbers of the three kind microorganism were increased by 114.9%、49.0% and 29.0%,respectively,in medium level of combined application of organic and inorganic fertilizer compared to medium level of pure inorganic fertilizer.(2) Fertilization can significantly enhance the enzyme activity of urease, invertase, phosphatase and catalase and soil respiration rate. Enzyme activity and soil respiration rate of medium and high level of combined application were much higher than that of the other treatments. The effect of pure inorganic fertilizer with medium level was near to,or lower in late growing stage, than that of low level of combined application. Fertilization had little effects on the activity of catalase than that of the other three enzymes. (3) Significant correlative relationships were found among soil microorganisms, soil enzyme activities and soil respiration. (4) Pod yields of peanut with medium and high level of combined application were much higher than that of other treatments, and increased by 14.0% in medium level of combined application compared to in pure medium level of inorganic fertilizer(normal rate for farmer land). So, the role of organic fertilizer to yield increase through improving soil fertility was far greater than that of its direct nourishment supply in sandy soil. (5)Taking into account both soil fertility and yield of peanut, medium level of combined application of organic and inorganic fertilizer was appropriate in middle-fertility sandy soil. 参考文献 相似文献 引证文献

Study of the Urease enzyme activity and the some effect factors on urea hydrolyses in some agriculture soils in Ramadia

The research has been carried out to study the existence, distribution and identified the isolated of urea hydrolysis bacteria and produced the urease from 30 samples have been collected from 6 regions agricultural soils felids between Ramadia and Heat city on the two sides of Euphrates river ( Gzeria and Zngora).3 regions for each Gzeria and Zngora that wheat and vegetable agriculture uses and wild, in the period march to July 2010. The samples were analyzed and limited 20 samples are positive for urea hydrolysis. The urease enzyme activity was also investigated, 5 isolates are belong to good urea hydrolysis bacteria have been selected and identified. The effects of some factors such as the temperatures, different concentrations of urea and different ratios of CaSO4. The results were as follows; The area of study was about 8000 ha., most soils’ had sandy loom texture , calcareous (CaCO3 18 – 23%), variation in gypsum content (2.53 – 14.12%), organic content (0.23 – 0.92%), soil salinity for agriculture fields (3.13 – 3.50 ds.m-1) but the wild soils increase to 4.52 ds.m-1. Urea applied was almost totally hydrolyzed to ammonia in all soils tested with 30 days and the best urease activity recorded 75, 80 µg urea.g.h-1 in the vegetable agriculture uses for Gzeria and Zngora soils alternately. Two bacterial isolates P. fluorescens GV2, Sp. urea ZV2 have achieved the best urease activity 8.40 ,7.99 mg.NH3 Lˉ1.hˉ1, Results have shown that the best activity of urea hydrolysis and Urease producing bacteria P. fluorescens GV2 and B.subtilisZB4 8.45 ,8.32 mg.NH3 Lˉ1.hˉ1 were at 38c˚ temperatures alternately. The isolates activity rate increased with increasing the urea concentration in the medium from 300to 900 mg urea Lˉ1. The highest rate was 62 mg NH3 Lˉ1. hˉ1 with 900 mg urea.Lˉ1 concentration by Sp. ureae ZV2. While the results have shown a decrease in the activity of isolates in hydrolyseis urea when using increased amounts of gypsum after 5%, the hydrolyze rate was 0.0 NH3 Lˉ1.hˉ1 for the B.subtilisZB4 at 10% gypsum and gradually decreased with increasing the amount of gypsum in the medium to reach 0.0 mg.NH3 Lˉ1.hˉ1 when using 15% of gypsum with Ur. pasteuri ZW4.

Immunological features and efficacy of the reconstructed epitope vaccine CtUBE against Helicobacter pylori infection in BALB/c mice model

Urease is an essential virulence factor and colonization factor for Helicobacter pylori, of which the urease B subunit (UreB) is considered as an excellent vaccine candidate antigen. In previous study, an epitope vaccine with cholera toxin B subunit (CTB) and an epitope (UreB321-339) named CtUBE was constructed and the mice were protected significantly after intragastric vaccination with the CtUBE liposome vaccine. However, the fusion protein CtUBE was expressed as inclusion bodies and was difficultly purified. Besides, the immunogenicity and specificity of the CtUBE vaccine was not investigated in a fairly wide and detailed way. In this study, the fusion peptide CtUBE was reconstructed and expressed as a soluble protein with pectinase signal peptide at the N terminus and the 6-his tag at its C-terminal, and then the immunogenicity, specificity, prophylactic, and therapeutic efficacy of the reconstructed CtUBE (rCtUBE) vaccine were evaluated in BALB/c mice model after purification. The experimental results indicated that mice immunized with rCtUBE could produce comparatively high level of specific antibodies which could respond to natural H. pylori urease, UreB, or the minimal epitope UreB327-334 involved with the active site of urease, and showed effectively inhibitory effect on the enzymatic activity of urease. Besides, oral prophylactic or therapeutic immunization with rCtUBE significantly decreased H. pylori colonization compared with oral immunization with rCTB or PBS, and the protection was correlated with antigen-specific IgG, IgA, and mucosal sIgA antibody responses, and a Th2 cells response. This rCtUBE vaccine may be a promising vaccine candidate for the control of H. pylori infection.