Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes we...Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.展开更多
The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils.For this purpose,a climosequence approach comprising no...The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils.For this purpose,a climosequence approach comprising north(N)and south(S)exposure along the altitudinal gradient(600,800,1000 and 1200 m a.s.l.)was set up.By comparing the properties of decomposing deadwood and those of the soils located directly beneath the decaying wood we drew conclusions about the role of deadwood in the shaping of soil organic matter fractions and soil carbon storage in different climate conditions.The basic properties,enzymatic activity and fractions of soil organic matter(SOM)were determined in deadwood and affected directly by the components released from decaying wood.Heavily decomposed deadwood impacts soil organic matter stabilization more strongly than the less decayed deadwood and the light fraction of SOM is more sensitive to deadwood effects than the heavy fraction regardless of the location in the altitude gradient.Increase in SOM mineral-associated fraction C content is more pronounced in soils under the influence of deadwood located in lower locations of warmer exposure.Nutrients released from decaying wood stimulate the enzymatic activity of soils that are within the range of deadwood influence.展开更多
[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity...[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.展开更多
[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbo...[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbon nanomaterials on soil enzyme activity was studied by adding graphene, graphene oxide and carbon nanotubes to turfgrass soil. [Results] Compared with the control(CK), the activity of soil protease, sucrase, alkaline phosphatase and catalase was not significantly affected by carbon nanomaterials. Under the treatment of carbon nanotubes, urease activity was significantly lower than that of graphene and graphene oxide, and dehydrogenase activity was significantly lower than that of the CK, graphene and graphene oxide. [Conclusions] This study provides a theoretical basis for the safe application of carbon nanomaterials.展开更多
[Objectives]This study was conducted to reveal the effects of bamboo charcoal-based biochar(or bamboo charcoal for short)on soil enzyme activity and microbial community structure.[Methods]The field experiment was carr...[Objectives]This study was conducted to reveal the effects of bamboo charcoal-based biochar(or bamboo charcoal for short)on soil enzyme activity and microbial community structure.[Methods]The field experiment was carried out at the Modern Agriculture Demonstration Base of Gaoping Village,Gaoping Town,Suichang County,Zhejiang Province.Bamboo charcoal was applied at four different levels:T_(0)(no bamboo charcoal),T_(1)(1125 kg/hm^(2)bamboo charcoal),T_(2)(2250 kg/hm^(2)bamboo charcoal)and T_(3)(3375 kg/hm^(2)bamboo charcoal).Soil physicochemical properties and enzyme activities in different treatments were measured.[Results]The soil fungal,bacterial and actinomycete populations increased significantly in the soils surrounding capsicum roots.The bacterial population,fungal population and fungus/bacterium ratio peaked in Treatment T_(2),up to 7.32×10^(6)cfu/g,2.65×10^(4)cfu/g and 0.36×10^(-2),respectively.The effect of bamboo charcoal in promotingβ-glucoside,catalase,acid phosphatase and sucrase activities was T_(2)>T_(3)>T_(1)>T_(0).With bamboo charcoal increasing,the bacterium population,fungus population,fungus/bacterium ratio,β-glucoside,catalase,acid phosphatase and sucrase activities all increased at first and then decreased.T_(2)treatment showed the best effects in improving soil physicochemical properties and microbial community structure.[Conclusions]Bamboo charcoal significantly improves soil enzyme activity and increases soil microbial population,and thus has important positive effects on the soil ecosystem.展开更多
The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in He...The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg·hm^(-2).展开更多
In order to find out changes in the main fertility indicators of continuous cropping tobacco fields in Henan Province with years of continuous cropping,5 typical tobacco fields( Jia County,Shaoling District,Fangcheng ...In order to find out changes in the main fertility indicators of continuous cropping tobacco fields in Henan Province with years of continuous cropping,5 typical tobacco fields( Jia County,Shaoling District,Fangcheng County,Xiangcheng County,and Song County) were studied. Indicators in question included activity of main enzymes( sucrase,urease,catalase,and acid phosphatase),p H value,organic matters,total nitrogen,available phosphorus and available potassium. The results indicate that in most tobacco fields,the activity of sucrase and urease increased in two years of continuous cropping,later,it showed a declining trend with increase in years of continuous cropping; in some fields,it directly declined with increase in years of continuous cropping; the activity of catalase increased in two years of continuous cropping,later,it showed a declining trend with increase in years of continuous cropping,and it became stable after three years of continuous cropping;generally,the activity of acid phosphatase declined with increase in the years of continuous cropping within 3 years continuous cropping,later,it became stable. Except Fangcheng County,the soil p H value of other districts( counties) generally declined with increase in years of continuous cropping,and it was in the range of 5. 6-6. 8. With the increase in continuous cropping,the soil organic matters( SOM) in tobacco fields of Jia County and Song County declined,changes of SOM in tobacco fields of Fangcheng County and Xiangcheng County were not obvious,and SOM showed the trend of first decline then rise in Shaoling District. In most tobacco fields( Jia County,Xiangcheng County,and Song County),the total nitrogen showed a declining trend; in Shaoling District,it showed a trend of first decline then rise; in Fangcheng County,it showed a rising trend. The available phosphorus firstly slightly declined then rose in tobacco fields of Shaoling District and Song County; it showed a trend of first rise then decline in Jia County; there were no obvious changes in Fangcheng County and Xiangcheng County. Changes in the available potassium were different in tobacco fields. In sum,there are certain rules for changes in soil enzyme activity and nutrient content in tobacco fields in Henan Province,but changes are not completely the same. It is concluded that the site conditions and farming activities exert a certain influence on soil enzyme activity,p H value,organic matters,and nitrogen,phosphorus and potassium content. Therefore,to solve obstacles in continuous cropping of tobacco fields,different regions should take different measures.展开更多
[Objectives]This study was conducted to investigate the effects of Vitis heyneana cultivation on rocky hillsides on the variation of soil fertility,so as to provide theoretical support for economic development and the...[Objectives]This study was conducted to investigate the effects of Vitis heyneana cultivation on rocky hillsides on the variation of soil fertility,so as to provide theoretical support for economic development and the control of rocky desertification in the Dashi mountainous area.[Methods]Taking V.heyneana planting base in Luocheng County,Hechi City,Guangxi Province as the research object,the methods of field investigation,regular sampling and experimental analysis were used to analyze seasonal variations of soil urease,sucrase and soil alkaline phosphatase activity of 15 different sample plots surveyed,and their correlation with soil physical and chemical properties was analyzed.[Results]①In general,sucrase,urease and alkaline phosphatase were lower in summer and autumn,and higher in spring and winter,and the performance of the activity of the three enzymes was inconsistent.Among them,the activity of sucrase was in order of spring>autumn>summer>winter,and the activity of urease and alkaline phosphatase showed an order of winter>spring>summer>autumn.②The seasonal variations of soil fertility in different sample plots were affected by various factors such as human disturbance,climate change,vegetation coverage,topography and landforms,cultivation and management measures,and although the change laws in different sample plots were different,the seasonal differences in soil fertility in the same place were extremely significant.③If the influence of artificial fertilization factors is excluded,the planting of V.heyneana on rocky hillsides will cause a significant decrease in soil enzyme activity,that is,a significant decrease in soil fertility.[Conclusions]Related issues such as the effects of planting V.heyneana on the variation of soil fertility in rocky hillsides should arouse necessary attention of management departments and producers.展开更多
Continuous cropping obstacles hamper the efficient growth and yield of Szechuan pepper,Zanthoxylum simulans.The current study investigated the impact of different levels of bioorganic fertilizer on the leaf physiologi...Continuous cropping obstacles hamper the efficient growth and yield of Szechuan pepper,Zanthoxylum simulans.The current study investigated the impact of different levels of bioorganic fertilizer on the leaf physiological and photosynthetic characteristics of Z.simulans to provide a theoretical reference for continuous Z.simulans crop cultivation.A bioorganic fertilizer was used to treat seedlings growing in 25-year-old continuous cropping soil.Five fertilizer treatments were applied.The impacts of the treatments on the activity of defense enzyme and photosynthetic parameters of Z.simulans leaves were determined.The different concentrations of bioorganic fertilizer reduced to varying degrees the malondialdehyde(MDA)content and intercellular CO2 concentration(Ci),and increased the activity of peroxidase(POD),superoxide dismutase(SOD),and ascorbate peroxidase(APX),as well as the chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of Z.simulans leaves.The results showed that most significant increases or decreases were achieved with 100 g/L bioorganic fertilizer(Y2).Thus,the application of bioorganic fertilizer at a rate of 100 g/L can significantly improve the activity of relevant defense enzymes and photosynthetic parameters of Z.simulans,and reduce the MDA content,enhancing the stress resistance of the plants,promoting their growth and addressing,to some extent,obstacles associated with continuous cultivation.展开更多
Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. Here, we performed a series of enzyme assays on pine bi...Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. Here, we performed a series of enzyme assays on pine biochar-amended soils, comparing multiple enzyme activities (EAs) simultaneously determined in the same soil sample vs. the sum of individual EAs involved in the C, N, S, and P cycles to provide information of the impacts of biochar on biogeochemical cycling. The combination of these four EAs has been considered an indicator of soil health due to their role in the reactions that release bioavailable nutrients in the cycling of C (β-glucosidase), N and C (β-glucosaminidase), P (acid phosphomonoesterase), and S (aryl-sulfatase) in soils. Comparisons of the theoretical EAs and the CNPS activity assay approaches in the biochar-modified soil revealed similar activity trends with the different concentrations of added biochar. Two years after adding biochar, study results showed the amended soils did not retain more pNP substrate than the un-amended control soils in three different pH buffers (5.5, 5.8, and 6.5) commonly used in EA reactions. Finally, we performed a third experiment to determine if the biochar previously added to the EAs interfered with the reactions’ enzyme or substrate. The results indicated that greater activity was measured using the combined assay, which suggests the CNPS activity method was less affected by biochar than the individual EAs. Our findings indicate that the potential soil biochemical-health index, CNPS activity (combination of four enzymes) assay is more robust than the individual EAs and can be used as an alternative tool to monitor soil functioning.展开更多
An in vitro study was conducted to investigate the impacts of microplastics on enzyme activities and soil bacteria. The study included four different treatments of microplastics including a control. Different levels o...An in vitro study was conducted to investigate the impacts of microplastics on enzyme activities and soil bacteria. The study included four different treatments of microplastics including a control. Different levels of microplastics were applied to the soil ranging from 0% to 5%, to assess the impacts of microplastics on soil enzymes and subsequent soil bacteria. After 30 days of incubation, the soil samples were collected and growth parameters of bacteria were assessed. Activities of β-glucosidase, urease and dehydrogenase enzymes were also determined. Our results showed that the presence of microplastics in the soil significantly reduced bacterial population together with bacterial strains. The activities of β-glucosidase, urease and dehydrogenase enzymes were reduced significantly to approximately 32%, 40% and 50% in microplastics treated soils respectively. Concentration of microplastic has a role to play towards this direction;the higher the concentration of microplastic the greater is the impact on enzymes and soil bacteria. The present study on the microbial soil health vis-à-vis microplastic application indicates that the material can have negative effect on the soil bacterial population of and thus ultimately may jeopardize soil health and crop production.展开更多
Background:Nitrogen(N)deposition alters litter decomposition and soil carbon(C)sequestration by influencing the microbial community and its enzyme activity.Natural atmospheric N deposition comprises of inorganic N(IN)...Background:Nitrogen(N)deposition alters litter decomposition and soil carbon(C)sequestration by influencing the microbial community and its enzyme activity.Natural atmospheric N deposition comprises of inorganic N(IN)and organic N(ON)compounds.However,most studies have focused on IN and its effect on soil C cycling,whereas the effect of ON on microbial enzyme activity is poorly understood.Here we studied the effects of different forms of externally supplied N on soil enzyme activities related to decomposition in a temperate steppe.Ammonium nitrate was chosen as IN source,whereas urea and glycine were chosen as ON sources.Different ratios of IN to ON(Control,10:0,7:3,5:5,3:7,and 0:10)were mixed with equal total amounts of N and then used to fertilize the grassland soils for 6 years.Results:Our results show that IN deposition inhibited lignin-degrading enzyme activity,such as phenol oxidase(POX)and peroxidase(PER),which may restrain decomposition and thus induce accumulation of recalcitrant organic C in grassland soils.By contrast,deposition of ON and mixed ON and IN enhanced most of the C-degrading enzyme activities,which may promote the organic matter decomposition in grassland soils.In addition,theβ-N-acetyl-glucosaminidase(NAG)activity was remarkably stimulated by fertilization with both IN and ON,maybe because of the elevated N availability and the lack of N limitation after long-term N fertilization at the grassland site.Meanwhile,differences in soil pH,soil dissolved organic carbon(DOC),and microbial biomass partially explained the differential effects on soil enzyme activity under different forms of N treatments.Conclusions:Our results emphasize the importance of organic N deposition in controlling soil processes,which are regulated by microbial enzyme activities,and may consequently change the ecological effect of N deposition.Thus,more ON deposition may promote the decomposition of soil organic matter thus converting C sequestration in grassland soils into a C source.展开更多
AIM: To examine the possible protective effect of Satureja khuzistanica essential oil(SKE) on antioxidant enzyme activity in alloxan-induced Type 1 diabetic rats. METHOD: Thirty Sprague-Dawley male rats were divided i...AIM: To examine the possible protective effect of Satureja khuzistanica essential oil(SKE) on antioxidant enzyme activity in alloxan-induced Type 1 diabetic rats. METHOD: Thirty Sprague-Dawley male rats were divided into three groups randomly; group one as control, group two diabetic, with no treatment, and group three treatment with SKE at 500 ppm in drinking water, respectively. Diabetes was induced in the second and third groups by alloxan injection subcutaneously. After eight weeks, animals were anaesthetized. Blood samples were also collected before killing to measure antioxidant enzymes activity. RESULTS: SKE significantly increased the serum level of glutathione and the serum activity of glutathione peroxidase, superoxide dismutase, and catalase in the treated group compared with the diabetic untreated group. CONCLUSION: The findings showed that SKE exerts beneficial effects on the antioxidant enzymes activity in alloxan-induced Type 1 diabetic rats.展开更多
A total of 480 day-old Cobb 500 broilers were used to investigate the effects of different levels of digestible amino acids(DAA; 100%, 107% and 114% of Cobb recommendations) and ME(3,000 or2,900 kcal/kg) of prestarter...A total of 480 day-old Cobb 500 broilers were used to investigate the effects of different levels of digestible amino acids(DAA; 100%, 107% and 114% of Cobb recommendations) and ME(3,000 or2,900 kcal/kg) of prestarter diet on mixed sex broilers performance, enzyme activity, small intestine morphology, and serum metabolites. Broilers were randomly allotted to 6 treatments, where each treatment applied to 4 pens with 20 birds in each. The birds were subjected to their respective treatment diets from 1 to 10 days of age. This was followed by feeding common starter and finisher diets for the last29 days. The enzyme activity of the pancreas was measured at 10 days of age. Morphometric indexes of jejunum were measured at 10 days of age and the end of the feeding period. Our results showed that the body weight(BW) increased as the DAA density of the prestarter diet increased from 100% to 114% over the first 10 days and the entire period of the study. Birds fed 114% DAA presented a better feed conversion ratio on day 10(P < 0.05). At day 39, carcass weight and breast yield increased as the DAA levels increased from 100% to 114%(P < 0.05). The whole intestine length, small intestine length, and weights of the pancreas were lower in birds fed 100% DAA-diets at 10 days of age(P < 0.05). Increasing the dietary DAA and ME did not affect serum amylase, lipase, and protease concentrations and pancreatic amylase and lipase activity(P > 0.05); however, the activity of pancreatic protease increased as the DAA level increased from 100% to 114%(P < 0.05). The villus width and villus surface area(VSA) increased as the DAA level increased from 100% to 114% on day 10(P < 0.05). At 10 days of age, crypt depth was the lowest in the birds fed plenty DAA prestarter diets(P < 0.05). It was found that dietary treatments at 39 days of age did not affect intestinal morphology. The results of the present work indicate that DAA level of 114% of Cobb recommendations and energy level of 2,900 kcal/kg diet may be recommended for starting broiler chicks.展开更多
Background:Glutaminase 1 is a phosphate-activated metabolic enzyme that catalyzes the first step of glutaminolysis,which converts glutamine into glutamate.Glutamate is the major neurotransmitter of excitatory synapses...Background:Glutaminase 1 is a phosphate-activated metabolic enzyme that catalyzes the first step of glutaminolysis,which converts glutamine into glutamate.Glutamate is the major neurotransmitter of excitatory synapses,executing important physiological functions in the central nervous system.There are two isoforms of glutaminase 1,KGA and GAC,both of which are generated through alternative splicing from the same gene.KGA and GAC both transcribe 1–14 exons in the N-terminal,but each has its unique C-terminal in the coding sequence.We have previously identified that KGA and GAC are differentially regulated during inflammatory stimulation and HIV infection.Furthermore,glutaminase 1 has been linked to brain diseases such as amyotrophic lateral sclerosis,Alzheimer’s disease,and hepatic encephalopathy.Core enzyme structure of KGA and GAC has been published recently.However,how other coding sequences affect their functional enzyme activity remains unclear.Methods:We cloned and performed serial deletions of human full-length KGA and GAC from the N-terminal and the C-terminal at an interval of approximately 100 amino acids(AAs).Prokaryotic expressions of the mutant glutaminase 1 protein and a glutaminase enzyme activity assay were used to determine if KGA and GAC have similar efficiency and efficacy to convert glutamine into glutamate.Results:When 110 AAs or 218 AAs were deleted from the N-terminal or when the unique portions of KGA and GAC that are beyond the 550 AA were deleted from the C-terminal,KGA and GAC retained enzyme activity comparable to the full length proteins.In contrast,deletion of 310 AAs or more from N-terminal or deletion of 450 AAs or more from C-terminal resulted in complete loss of enzyme activity for KGA/GAC.Consistently,when both Nand C-terminal of the KGA and GAC were removed,creating a truncated protein that expressed the central 219 AA-550 AA,the protein retained enzyme activity.Furthermore,expression of the core 219 AA-550 AA coding sequence in cells increased extracellular glutamate concentrations to levels comparable to those of full-length KGA and GAC expressions,suggesting that the core enzyme activity of the protein lies within the central 219 AA-550 AA.Full-length KGA and GAC retained enzyme activities when kept at 4°C.In contrast,219 AA-550 AA truncated protein lost glutaminase activities more readily compared with full-length KGA and GAC,suggesting that the Nterminal and C-terminal coding regions are required for the stability KGA and GAC.Conclusions:Glutaminase isoforms KGA and GAC have similar efficacy to catalyze the conversion of glutamine to glutamate.The core enzyme activity of glutaminase 1 protein is within the central 219 AA-550 AA.The N-terminal and C-terminal coding regions of KGA and GAC help maintain the long-term activities of the enzymes.展开更多
Tgf2 transposase(Tgf2-TPase),a hAT transposase from goldfish,plays an important role in fish transgenic applications.Previously,the production of the recombinant Tgf2-TPase protein required rigorous fermentation at lo...Tgf2 transposase(Tgf2-TPase),a hAT transposase from goldfish,plays an important role in fish transgenic applications.Previously,the production of the recombinant Tgf2-TPase protein required rigorous fermentation at low temperatures(22℃)and early log phase induction(OD600=0.3–0.4)in Rosetta 1(DE3)Escherichia coli lines.In order to better express the Tgf2-TPase and detect its enzyme activity,83 rare codons in Tgf2-TPase were optimized and designated Tgf2-TPase^(83).The expression results showed that the soluble recombinant Tgf2-TPase83 was highly expressed at 30℃ and was inducible at an OD600 of 0.5–0.6 in the same prokaryotic expression system.After purification by affinity chromatography,Tgf2-TPase83 with codon optimization had higher enzyme activity than the Tgf2-TPase control.Comparison of different preservation methods(freezedrying at−80℃,storage in 20%-glycerol,8%-sucrose,4%-mannitol),revealed storage of Tgf2-TPase^(83) in glycerol helped to preserve its DNase digestion activity.Furthermore,size exclusion chromatography suggested that the purified Tgf2-TPase^(83) could recognize and bind to DNA probes containing a terminal inverted repeat(TIR)and a subterminal repeat(STR)sequence of the Tgf2 transposon.Overall,the results showed that optimizing the 83 codons of Tgf2 transposase can simplify the fermentation process and improve the enzyme activity.We propose that the production of the Tgf2-Tpase83 protein in a soluble and active form could provide an alternative tool for genetic modification of fish.展开更多
Background and objective:Activated carbon is commonly used as an immobilisation matrix due to its large surface area,making it a highly desirable matrix for use in immobilising enzymes as preparation for use on the in...Background and objective:Activated carbon is commonly used as an immobilisation matrix due to its large surface area,making it a highly desirable matrix for use in immobilising enzymes as preparation for use on the industrial scale.The objective of this research is to determine the effectiveness of different acids for functionalisation on immobilisation capacity and also to characterize the functionalized activated carbon for the functional groups present.Materials and methods:Activated carbon was functionalised with three acids(hydrochloric acid,nitric acid and sulphuric acid)along with a control sample washed with distilled water.Immobilisation capacity was calculated with hydrochloric acid functionalized activated carbon(HCl-FAC)giving the highest immobilization capacity(6.022 U/g).Characterisation of the functionalised activated carbon was conducted using FT-IR(Fourier Transform Infra-Red)spectroscopy analysis of the samples with the aim of analyzing the various functional groups present to determine the sample with distinct characteristics thus telling the degree of adsorption of lipase onto the activated carbon powder.Results:HNO3-FAC(functionalized activated carbon)showed a very distinct pattern as a larger number of surface functional groups emerged.The immobilisation on a matrix ensures thermal stability and increased reusability of the enzyme.Therefore,in this research,lipase sourced from Candida antarctica was immobilised on acid functionalised activated carbon.The best acid for functionalisation was found to be hydrochloric acid.Conclusion:Due to the very distinct patterns shown by the FT-IR spectrum of the HNO3-FAC after a fair comparison with others,it allows for a larger number of surface functional groups which will definitely enhance the stability of the enzyme lipase.展开更多
In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer ...In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer on plant nitrogen utilization is not clear.A study was,therefore,conducted to explore the activities and gene expression of key enzymes for nitrogen assimilation and the gene expression of nitrogen transporters in wheat after the application of synergistic fertilizer.Soil column experiment was set up in Qingdao Agricultural University experimental base from October 2018 to June 2019.Maleic acid and itaconic acid were copolymerized with acrylic acid as cross-linking monomer to make a fluid gel,which was sprayed on the fertilizer surface to make nitrogen and phosphorus synergistic fertilizer.A total of 6 treatments was set according to different nitrogen and phosphorus fertilizer ratios:(1)100%common nitrogen fertilizer+100%common phosphate fertilizer(2)70%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(3)100%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(4)100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(5)70%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(6)100%commercial nitrogen synergistic fertilizer+100%commercial phosphorus synergistic fertilizer.The results are as follows:(1)the enzyme activities of wheat plants under synergistic fertilizer condition were higher than those under ordinary fertilizer,except under the treatment that nitrogen and phosphorus synergistic fertilizer were both reduced;(2)the expression level of the genes under the treatment“100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer”was significantly higher than those in other treatments.Combined with the higher performance of nitrogen concentration in various parts of the plant under the condition of applying synergistic fertilizer,this study indicated that the application of synergistic fertilizer can improve the nitrogen metabolism of the plant by increasing the nitrogen level in the rhizosphere soil,inducing the expression of nitrogen transporter genes and key assimilation enzymes genes.展开更多
Crop rotation periodicity has always been one of the research focuses currently. In this study, the physicochemical properties, nutrient contents and enzyme activities were investigated in soils from rice-cherry tomat...Crop rotation periodicity has always been one of the research focuses currently. In this study, the physicochemical properties, nutrient contents and enzyme activities were investigated in soils from rice-cherry tomato rotation for one year (1a), three years (3a), five years (5a), seven years (7a) and ten years (10a), respectively. The major objective was to analyze the optimal rotation years of rice-cherry tomato from soil perspective, so as to provide theoretical basis for effectively avoiding continuous cropping obstacles of cherry tomato via studying the response characteristics of soil physicochemical properties, nutrient contents and enzyme activities to planting years of rice-cherry tomato rotation system. The results were as follows: 1) Soil pH value was increased year by year during 1a to 5a, reached the highest value 5.32 at 5a. However, soil acidity was sharply enhanced during 7a to 10a (P P •kg<sup>-1</sup> at 5a. 3) The content of soil available phosphorus was increased year by year with increasing of crop rotation years, and increased by 110% to 173% during 3a to 10a (P P P < 0.05). In conclusion, long-term single rotation pattern of rice-cherry tomato would aggravate soil acidification, prompt soil nutrient imbalance and reduce soil enzyme activity. 5a to 7a would be the appropriate rotation period for rice-cherry tomato, or else it would reduce soil quality, resulting in a new continuous cropping obstacle of cherry tomato.展开更多
Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in...Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods(continuous flooding(CF), continuous flooding and aeration(CFA), and alternate wetting and drying(AWD)). The abundances of amoA ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering(S1), heading(S2), and ripening(S3) stages. We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon(MBC) and soil microbial biomass nitrogen(MBN), with the concentration of soil nitrate and ammonium nitrogen. The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments. AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong. During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively. The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively. The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase. All the above indicators were positively correlated with soil MBC and MBN. In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2. Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation.展开更多
基金This study received financial support from the Youth Talents Special Project of Yunnan Province,“Xingdian Talents Support Program”(XDYC-QNRC-2022-0203)Southwest Forestry University Scientific Research Start-Up Funds(112116).
文摘Phenylalanine ammonia lyase(PAL)is the rate-limiting and pivotal enzyme of the general phenylpropanoid path-way,but few reports have been found on PAL genes in Pinus yunnanensis.In the present study,three PAL genes were cloned and identified from P.yunnanensis seedlings for thefirst time,namely,PyPAL-1,PyPAL-2,and PyPAL-3.Our results indicated that the open-reading frames of PyPAL genes were 2184,2157,and 2385 bp.Phylogenetic tree analysis revealed that PyPALs have high homology with other known PAL genes in other plants.In vitro enzymatic analysis showed that all three PyPAL recombinant proteins could catalyze the deamination of L-phenylalanine to form trans-cinnamic acid,but only PAL1 and PAL2 can catalyze the conversion of L-tyrosine toρ-coumaric acid.Three PyPAL genes were expressed in different tissues in 1-year-old P.yunnanensis,and such genes had different expression patterns.This study lays a foundation for further understanding of the biosynthesis of secondary metabolites in P.yunnanensis.
基金financed by the National Science Centre,Poland:decision no.DEC 2020/39/B/NZ9/00372
文摘The main objective of our study has been to determine the role of deadwood in the shaping of the amount of soil organic matter fractions in mountain forest soils.For this purpose,a climosequence approach comprising north(N)and south(S)exposure along the altitudinal gradient(600,800,1000 and 1200 m a.s.l.)was set up.By comparing the properties of decomposing deadwood and those of the soils located directly beneath the decaying wood we drew conclusions about the role of deadwood in the shaping of soil organic matter fractions and soil carbon storage in different climate conditions.The basic properties,enzymatic activity and fractions of soil organic matter(SOM)were determined in deadwood and affected directly by the components released from decaying wood.Heavily decomposed deadwood impacts soil organic matter stabilization more strongly than the less decayed deadwood and the light fraction of SOM is more sensitive to deadwood effects than the heavy fraction regardless of the location in the altitude gradient.Increase in SOM mineral-associated fraction C content is more pronounced in soils under the influence of deadwood located in lower locations of warmer exposure.Nutrients released from decaying wood stimulate the enzymatic activity of soils that are within the range of deadwood influence.
基金Supported by Key R&D Program of the Ministry of Science and Technology of China(2017YFC0505102-4)。
文摘[Objectives]In response to the issue of soil improvement in Yuanmou County,the effects of combined application of biochar-based organic fertilizer and reduced nitrogen fertilizer on soil nutrients,soil enzyme activity,and yield of purple cabbage(Brassica oleracea var.capita rubra)were investigated in the field base of Institute of Thermal Zone Ecological Agriculture,Yunnan Academy of Agricultural Sciences in Yuanmou County.[Methods]A total of 13 treatments were set up by applying biochar-based organic fertilizer at three levels of 15,30 and 45 t/hm^(2)(T_(1),T_(2),T_(3)),combined with top application of nitrogen fertilizer(urea)at four levels:375(N_1),300(N_(2)),225(N_(3))and 0 kg/hm^(2),with non-fertilizing treatment as control check(CK),in order to explore the optimal ratio for the combined application of biochar-based organic fertilizer with nitrogen fertilizer.[Results]The application of biochar-based organic fertilizer could significantly improve soil nutrients,enzyme activity,and purple cabbage yield.The improvement effect of combined application with nitrogen fertilizer was higher than that of single application of biochar-based organic fertilizer,and the improvement effect was enhanced with the application amount of biochar-based organic fertilizer increasing.The contents of organic matter and total nitrogen were the highest in treatment T_(3)N_(3),of which the values increased by 81.39%and 56.09%compared with the CK,respectively.The contents of soil hydrolyzable nitrogen,available phosphorus,and available potassium were all the highest under treatment T_(3)N_(2),with increases of 92.76%,171.01%and 235.50%,respectively.There was a significant positive correlation between the activity of soil catalase,urease,and sucrase and organic matter,total nitrogen,and available nutrients.The overall soil enzyme activity was relatively higher in treatment T_(3)N_(2).The yield of purple cabbage treated with biochar-based organic fertilizer combined with nitrogen fertilizer could reach 85750 kg/hm^(2),which was 94.78%higher than that treated with biochar-based organic fertilizer alone.Based on comprehensive analysis,the optimal combination ratio was 45 t/hm^(2)of biochar-based organic fertilizer and 300 kg/hm^(2)of urea(T_(3)N_(2)).[Conclusions]This study provides data support for the promotion of biochar-based organic fertilizers and reduced fertilizer in agricultural soil in the Dam area of Yuanmou County.
基金Supported by National Natural Science Foundation of China (31870484)。
文摘[Objectives]This study was conducted to evaluate the effects of carbon nanomaterials on soil ecosystem and explore the ecological risks of environmental exposure of carbon nanomaterials. [Methods] The effects of carbon nanomaterials on soil enzyme activity was studied by adding graphene, graphene oxide and carbon nanotubes to turfgrass soil. [Results] Compared with the control(CK), the activity of soil protease, sucrase, alkaline phosphatase and catalase was not significantly affected by carbon nanomaterials. Under the treatment of carbon nanotubes, urease activity was significantly lower than that of graphene and graphene oxide, and dehydrogenase activity was significantly lower than that of the CK, graphene and graphene oxide. [Conclusions] This study provides a theoretical basis for the safe application of carbon nanomaterials.
基金Supported by Special Fund of Lishui City for Public Interest(2021GYX11)Special Fund of Zhejiang Provincial Department of Finance for Basic Research and Development of Bamboo Charcoal-based Soil Conditioner(20180021)Key Research and Development Project of Zhejiang Province(2018C02031)。
文摘[Objectives]This study was conducted to reveal the effects of bamboo charcoal-based biochar(or bamboo charcoal for short)on soil enzyme activity and microbial community structure.[Methods]The field experiment was carried out at the Modern Agriculture Demonstration Base of Gaoping Village,Gaoping Town,Suichang County,Zhejiang Province.Bamboo charcoal was applied at four different levels:T_(0)(no bamboo charcoal),T_(1)(1125 kg/hm^(2)bamboo charcoal),T_(2)(2250 kg/hm^(2)bamboo charcoal)and T_(3)(3375 kg/hm^(2)bamboo charcoal).Soil physicochemical properties and enzyme activities in different treatments were measured.[Results]The soil fungal,bacterial and actinomycete populations increased significantly in the soils surrounding capsicum roots.The bacterial population,fungal population and fungus/bacterium ratio peaked in Treatment T_(2),up to 7.32×10^(6)cfu/g,2.65×10^(4)cfu/g and 0.36×10^(-2),respectively.The effect of bamboo charcoal in promotingβ-glucoside,catalase,acid phosphatase and sucrase activities was T_(2)>T_(3)>T_(1)>T_(0).With bamboo charcoal increasing,the bacterium population,fungus population,fungus/bacterium ratio,β-glucoside,catalase,acid phosphatase and sucrase activities all increased at first and then decreased.T_(2)treatment showed the best effects in improving soil physicochemical properties and microbial community structure.[Conclusions]Bamboo charcoal significantly improves soil enzyme activity and increases soil microbial population,and thus has important positive effects on the soil ecosystem.
文摘The experiment was conducted to study the impact of application of microbial inoculants, compared with no microbial fertilizer, on enzyme activity, microbial biomass and available nutrient contents in paddy soil in Heilongjiang Province. The application of soil phosphorus activator was able to increase the quantity of bacteria and fungi in soil, but its effect on actinomycetes in soil was not significant. The application of microbial inoculants increased the urease and sucrase activities in soil over the growing season, but only at the maturing stage soil acid phosphatase activity was enhanced with the applying soil phosphorus activator. The application of soil phosphorus activator increased alkali-hydrolyzable nitrogen and available phosphorus contents in soil, but did not increase available potassium content in soil. The optimal microbial inoculant application rate as applied as soil phosphorus activator was 7.5 kg·hm^(-2).
基金Supported by Key Scientific and Technological Plan Project of Henan Tobacco Company(HYKJM201304)
文摘In order to find out changes in the main fertility indicators of continuous cropping tobacco fields in Henan Province with years of continuous cropping,5 typical tobacco fields( Jia County,Shaoling District,Fangcheng County,Xiangcheng County,and Song County) were studied. Indicators in question included activity of main enzymes( sucrase,urease,catalase,and acid phosphatase),p H value,organic matters,total nitrogen,available phosphorus and available potassium. The results indicate that in most tobacco fields,the activity of sucrase and urease increased in two years of continuous cropping,later,it showed a declining trend with increase in years of continuous cropping; in some fields,it directly declined with increase in years of continuous cropping; the activity of catalase increased in two years of continuous cropping,later,it showed a declining trend with increase in years of continuous cropping,and it became stable after three years of continuous cropping;generally,the activity of acid phosphatase declined with increase in the years of continuous cropping within 3 years continuous cropping,later,it became stable. Except Fangcheng County,the soil p H value of other districts( counties) generally declined with increase in years of continuous cropping,and it was in the range of 5. 6-6. 8. With the increase in continuous cropping,the soil organic matters( SOM) in tobacco fields of Jia County and Song County declined,changes of SOM in tobacco fields of Fangcheng County and Xiangcheng County were not obvious,and SOM showed the trend of first decline then rise in Shaoling District. In most tobacco fields( Jia County,Xiangcheng County,and Song County),the total nitrogen showed a declining trend; in Shaoling District,it showed a trend of first decline then rise; in Fangcheng County,it showed a rising trend. The available phosphorus firstly slightly declined then rose in tobacco fields of Shaoling District and Song County; it showed a trend of first rise then decline in Jia County; there were no obvious changes in Fangcheng County and Xiangcheng County. Changes in the available potassium were different in tobacco fields. In sum,there are certain rules for changes in soil enzyme activity and nutrient content in tobacco fields in Henan Province,but changes are not completely the same. It is concluded that the site conditions and farming activities exert a certain influence on soil enzyme activity,p H value,organic matters,and nitrogen,phosphorus and potassium content. Therefore,to solve obstacles in continuous cropping of tobacco fields,different regions should take different measures.
基金Natural Science Foundation of Guangxi(GKZ 0832273)Laboratory of Comprehensive Prevention and Control of Rocky Desertification in Karst Areas in Northwest Guangxi(XZF[2016]91)+1 种基金High-level Talent Research Startup Fund of Hechi University(XJ2018GKQ016)Undergraduate Innovation and Enterpreneurship Training Program of Guangxi(201810605086).
文摘[Objectives]This study was conducted to investigate the effects of Vitis heyneana cultivation on rocky hillsides on the variation of soil fertility,so as to provide theoretical support for economic development and the control of rocky desertification in the Dashi mountainous area.[Methods]Taking V.heyneana planting base in Luocheng County,Hechi City,Guangxi Province as the research object,the methods of field investigation,regular sampling and experimental analysis were used to analyze seasonal variations of soil urease,sucrase and soil alkaline phosphatase activity of 15 different sample plots surveyed,and their correlation with soil physical and chemical properties was analyzed.[Results]①In general,sucrase,urease and alkaline phosphatase were lower in summer and autumn,and higher in spring and winter,and the performance of the activity of the three enzymes was inconsistent.Among them,the activity of sucrase was in order of spring>autumn>summer>winter,and the activity of urease and alkaline phosphatase showed an order of winter>spring>summer>autumn.②The seasonal variations of soil fertility in different sample plots were affected by various factors such as human disturbance,climate change,vegetation coverage,topography and landforms,cultivation and management measures,and although the change laws in different sample plots were different,the seasonal differences in soil fertility in the same place were extremely significant.③If the influence of artificial fertilization factors is excluded,the planting of V.heyneana on rocky hillsides will cause a significant decrease in soil enzyme activity,that is,a significant decrease in soil fertility.[Conclusions]Related issues such as the effects of planting V.heyneana on the variation of soil fertility in rocky hillsides should arouse necessary attention of management departments and producers.
基金This study was supported by the Central Committee for guiding the local science and technology development sub-project“Study on the Structural Adjustment and Optimization Research and Platform Construction of the Characteristic Economic Forest and Pepper in Longnan”,and thanks for the International Science Editing(http://www.Internationalscienceediting.com)for editing this manuscript.
文摘Continuous cropping obstacles hamper the efficient growth and yield of Szechuan pepper,Zanthoxylum simulans.The current study investigated the impact of different levels of bioorganic fertilizer on the leaf physiological and photosynthetic characteristics of Z.simulans to provide a theoretical reference for continuous Z.simulans crop cultivation.A bioorganic fertilizer was used to treat seedlings growing in 25-year-old continuous cropping soil.Five fertilizer treatments were applied.The impacts of the treatments on the activity of defense enzyme and photosynthetic parameters of Z.simulans leaves were determined.The different concentrations of bioorganic fertilizer reduced to varying degrees the malondialdehyde(MDA)content and intercellular CO2 concentration(Ci),and increased the activity of peroxidase(POD),superoxide dismutase(SOD),and ascorbate peroxidase(APX),as well as the chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr)of Z.simulans leaves.The results showed that most significant increases or decreases were achieved with 100 g/L bioorganic fertilizer(Y2).Thus,the application of bioorganic fertilizer at a rate of 100 g/L can significantly improve the activity of relevant defense enzymes and photosynthetic parameters of Z.simulans,and reduce the MDA content,enhancing the stress resistance of the plants,promoting their growth and addressing,to some extent,obstacles associated with continuous cultivation.
文摘Biochar offers several benefits as a soil amendment, including increased soil fertility, carbon sequestration, and water-holding capacity in nutrient-poor soils. Here, we performed a series of enzyme assays on pine biochar-amended soils, comparing multiple enzyme activities (EAs) simultaneously determined in the same soil sample vs. the sum of individual EAs involved in the C, N, S, and P cycles to provide information of the impacts of biochar on biogeochemical cycling. The combination of these four EAs has been considered an indicator of soil health due to their role in the reactions that release bioavailable nutrients in the cycling of C (β-glucosidase), N and C (β-glucosaminidase), P (acid phosphomonoesterase), and S (aryl-sulfatase) in soils. Comparisons of the theoretical EAs and the CNPS activity assay approaches in the biochar-modified soil revealed similar activity trends with the different concentrations of added biochar. Two years after adding biochar, study results showed the amended soils did not retain more pNP substrate than the un-amended control soils in three different pH buffers (5.5, 5.8, and 6.5) commonly used in EA reactions. Finally, we performed a third experiment to determine if the biochar previously added to the EAs interfered with the reactions’ enzyme or substrate. The results indicated that greater activity was measured using the combined assay, which suggests the CNPS activity method was less affected by biochar than the individual EAs. Our findings indicate that the potential soil biochemical-health index, CNPS activity (combination of four enzymes) assay is more robust than the individual EAs and can be used as an alternative tool to monitor soil functioning.
文摘An in vitro study was conducted to investigate the impacts of microplastics on enzyme activities and soil bacteria. The study included four different treatments of microplastics including a control. Different levels of microplastics were applied to the soil ranging from 0% to 5%, to assess the impacts of microplastics on soil enzymes and subsequent soil bacteria. After 30 days of incubation, the soil samples were collected and growth parameters of bacteria were assessed. Activities of β-glucosidase, urease and dehydrogenase enzymes were also determined. Our results showed that the presence of microplastics in the soil significantly reduced bacterial population together with bacterial strains. The activities of β-glucosidase, urease and dehydrogenase enzymes were reduced significantly to approximately 32%, 40% and 50% in microplastics treated soils respectively. Concentration of microplastic has a role to play towards this direction;the higher the concentration of microplastic the greater is the impact on enzymes and soil bacteria. The present study on the microbial soil health vis-à-vis microplastic application indicates that the material can have negative effect on the soil bacterial population of and thus ultimately may jeopardize soil health and crop production.
基金supported by the National Natural Science Foundation of China(32022054,31901137)China Postdoctoral Science Foundation(2018M640263)+2 种基金Instrument Developing Project of CAS(YJKYYQ20190079)Strategic Priority Research Program of CAS(Grant No.XDA28120100)Youth Innovation Promotion Association of CAS(2019198)。
文摘Background:Nitrogen(N)deposition alters litter decomposition and soil carbon(C)sequestration by influencing the microbial community and its enzyme activity.Natural atmospheric N deposition comprises of inorganic N(IN)and organic N(ON)compounds.However,most studies have focused on IN and its effect on soil C cycling,whereas the effect of ON on microbial enzyme activity is poorly understood.Here we studied the effects of different forms of externally supplied N on soil enzyme activities related to decomposition in a temperate steppe.Ammonium nitrate was chosen as IN source,whereas urea and glycine were chosen as ON sources.Different ratios of IN to ON(Control,10:0,7:3,5:5,3:7,and 0:10)were mixed with equal total amounts of N and then used to fertilize the grassland soils for 6 years.Results:Our results show that IN deposition inhibited lignin-degrading enzyme activity,such as phenol oxidase(POX)and peroxidase(PER),which may restrain decomposition and thus induce accumulation of recalcitrant organic C in grassland soils.By contrast,deposition of ON and mixed ON and IN enhanced most of the C-degrading enzyme activities,which may promote the organic matter decomposition in grassland soils.In addition,theβ-N-acetyl-glucosaminidase(NAG)activity was remarkably stimulated by fertilization with both IN and ON,maybe because of the elevated N availability and the lack of N limitation after long-term N fertilization at the grassland site.Meanwhile,differences in soil pH,soil dissolved organic carbon(DOC),and microbial biomass partially explained the differential effects on soil enzyme activity under different forms of N treatments.Conclusions:Our results emphasize the importance of organic N deposition in controlling soil processes,which are regulated by microbial enzyme activities,and may consequently change the ecological effect of N deposition.Thus,more ON deposition may promote the decomposition of soil organic matter thus converting C sequestration in grassland soils into a C source.
文摘AIM: To examine the possible protective effect of Satureja khuzistanica essential oil(SKE) on antioxidant enzyme activity in alloxan-induced Type 1 diabetic rats. METHOD: Thirty Sprague-Dawley male rats were divided into three groups randomly; group one as control, group two diabetic, with no treatment, and group three treatment with SKE at 500 ppm in drinking water, respectively. Diabetes was induced in the second and third groups by alloxan injection subcutaneously. After eight weeks, animals were anaesthetized. Blood samples were also collected before killing to measure antioxidant enzymes activity. RESULTS: SKE significantly increased the serum level of glutathione and the serum activity of glutathione peroxidase, superoxide dismutase, and catalase in the treated group compared with the diabetic untreated group. CONCLUSION: The findings showed that SKE exerts beneficial effects on the antioxidant enzymes activity in alloxan-induced Type 1 diabetic rats.
文摘A total of 480 day-old Cobb 500 broilers were used to investigate the effects of different levels of digestible amino acids(DAA; 100%, 107% and 114% of Cobb recommendations) and ME(3,000 or2,900 kcal/kg) of prestarter diet on mixed sex broilers performance, enzyme activity, small intestine morphology, and serum metabolites. Broilers were randomly allotted to 6 treatments, where each treatment applied to 4 pens with 20 birds in each. The birds were subjected to their respective treatment diets from 1 to 10 days of age. This was followed by feeding common starter and finisher diets for the last29 days. The enzyme activity of the pancreas was measured at 10 days of age. Morphometric indexes of jejunum were measured at 10 days of age and the end of the feeding period. Our results showed that the body weight(BW) increased as the DAA density of the prestarter diet increased from 100% to 114% over the first 10 days and the entire period of the study. Birds fed 114% DAA presented a better feed conversion ratio on day 10(P < 0.05). At day 39, carcass weight and breast yield increased as the DAA levels increased from 100% to 114%(P < 0.05). The whole intestine length, small intestine length, and weights of the pancreas were lower in birds fed 100% DAA-diets at 10 days of age(P < 0.05). Increasing the dietary DAA and ME did not affect serum amylase, lipase, and protease concentrations and pancreatic amylase and lipase activity(P > 0.05); however, the activity of pancreatic protease increased as the DAA level increased from 100% to 114%(P < 0.05). The villus width and villus surface area(VSA) increased as the DAA level increased from 100% to 114% on day 10(P < 0.05). At 10 days of age, crypt depth was the lowest in the birds fed plenty DAA prestarter diets(P < 0.05). It was found that dietary treatments at 39 days of age did not affect intestinal morphology. The results of the present work indicate that DAA level of 114% of Cobb recommendations and energy level of 2,900 kcal/kg diet may be recommended for starting broiler chicks.
基金This work was partly supported by National Basic Research Program of China(973 Program Grant 2014CB965000,project 1 Grant 2014CB965001,and project 3 Grant 2014CB965003)National Natural Science Foundation of China(Grants 81271419 and 81271420)+1 种基金Joint Research Fund for Overseas Chinese,Hong Kong and Macao Young Scientists of the National Natural Science Foundation of China(Grant 81329002)National Institutes of Health:2R56NS041858-15A1(JZ),1R01NS097195-01(JZ),and R03 NS094071-01(YH).
文摘Background:Glutaminase 1 is a phosphate-activated metabolic enzyme that catalyzes the first step of glutaminolysis,which converts glutamine into glutamate.Glutamate is the major neurotransmitter of excitatory synapses,executing important physiological functions in the central nervous system.There are two isoforms of glutaminase 1,KGA and GAC,both of which are generated through alternative splicing from the same gene.KGA and GAC both transcribe 1–14 exons in the N-terminal,but each has its unique C-terminal in the coding sequence.We have previously identified that KGA and GAC are differentially regulated during inflammatory stimulation and HIV infection.Furthermore,glutaminase 1 has been linked to brain diseases such as amyotrophic lateral sclerosis,Alzheimer’s disease,and hepatic encephalopathy.Core enzyme structure of KGA and GAC has been published recently.However,how other coding sequences affect their functional enzyme activity remains unclear.Methods:We cloned and performed serial deletions of human full-length KGA and GAC from the N-terminal and the C-terminal at an interval of approximately 100 amino acids(AAs).Prokaryotic expressions of the mutant glutaminase 1 protein and a glutaminase enzyme activity assay were used to determine if KGA and GAC have similar efficiency and efficacy to convert glutamine into glutamate.Results:When 110 AAs or 218 AAs were deleted from the N-terminal or when the unique portions of KGA and GAC that are beyond the 550 AA were deleted from the C-terminal,KGA and GAC retained enzyme activity comparable to the full length proteins.In contrast,deletion of 310 AAs or more from N-terminal or deletion of 450 AAs or more from C-terminal resulted in complete loss of enzyme activity for KGA/GAC.Consistently,when both Nand C-terminal of the KGA and GAC were removed,creating a truncated protein that expressed the central 219 AA-550 AA,the protein retained enzyme activity.Furthermore,expression of the core 219 AA-550 AA coding sequence in cells increased extracellular glutamate concentrations to levels comparable to those of full-length KGA and GAC expressions,suggesting that the core enzyme activity of the protein lies within the central 219 AA-550 AA.Full-length KGA and GAC retained enzyme activities when kept at 4°C.In contrast,219 AA-550 AA truncated protein lost glutaminase activities more readily compared with full-length KGA and GAC,suggesting that the Nterminal and C-terminal coding regions are required for the stability KGA and GAC.Conclusions:Glutaminase isoforms KGA and GAC have similar efficacy to catalyze the conversion of glutamine to glutamate.The core enzyme activity of glutaminase 1 protein is within the central 219 AA-550 AA.The N-terminal and C-terminal coding regions of KGA and GAC help maintain the long-term activities of the enzymes.
基金This work was supported by the National Science Foundation of China(31572220,31272633,31201760)the National High Technology Research and Development Program of China(863 Program)(2011AA100403)the Shanghai University Knowledge Service Platform(ZF1206).
文摘Tgf2 transposase(Tgf2-TPase),a hAT transposase from goldfish,plays an important role in fish transgenic applications.Previously,the production of the recombinant Tgf2-TPase protein required rigorous fermentation at low temperatures(22℃)and early log phase induction(OD600=0.3–0.4)in Rosetta 1(DE3)Escherichia coli lines.In order to better express the Tgf2-TPase and detect its enzyme activity,83 rare codons in Tgf2-TPase were optimized and designated Tgf2-TPase^(83).The expression results showed that the soluble recombinant Tgf2-TPase83 was highly expressed at 30℃ and was inducible at an OD600 of 0.5–0.6 in the same prokaryotic expression system.After purification by affinity chromatography,Tgf2-TPase83 with codon optimization had higher enzyme activity than the Tgf2-TPase control.Comparison of different preservation methods(freezedrying at−80℃,storage in 20%-glycerol,8%-sucrose,4%-mannitol),revealed storage of Tgf2-TPase^(83) in glycerol helped to preserve its DNase digestion activity.Furthermore,size exclusion chromatography suggested that the purified Tgf2-TPase^(83) could recognize and bind to DNA probes containing a terminal inverted repeat(TIR)and a subterminal repeat(STR)sequence of the Tgf2 transposon.Overall,the results showed that optimizing the 83 codons of Tgf2 transposase can simplify the fermentation process and improve the enzyme activity.We propose that the production of the Tgf2-Tpase83 protein in a soluble and active form could provide an alternative tool for genetic modification of fish.
文摘Background and objective:Activated carbon is commonly used as an immobilisation matrix due to its large surface area,making it a highly desirable matrix for use in immobilising enzymes as preparation for use on the industrial scale.The objective of this research is to determine the effectiveness of different acids for functionalisation on immobilisation capacity and also to characterize the functionalized activated carbon for the functional groups present.Materials and methods:Activated carbon was functionalised with three acids(hydrochloric acid,nitric acid and sulphuric acid)along with a control sample washed with distilled water.Immobilisation capacity was calculated with hydrochloric acid functionalized activated carbon(HCl-FAC)giving the highest immobilization capacity(6.022 U/g).Characterisation of the functionalised activated carbon was conducted using FT-IR(Fourier Transform Infra-Red)spectroscopy analysis of the samples with the aim of analyzing the various functional groups present to determine the sample with distinct characteristics thus telling the degree of adsorption of lipase onto the activated carbon powder.Results:HNO3-FAC(functionalized activated carbon)showed a very distinct pattern as a larger number of surface functional groups emerged.The immobilisation on a matrix ensures thermal stability and increased reusability of the enzyme.Therefore,in this research,lipase sourced from Candida antarctica was immobilised on acid functionalised activated carbon.The best acid for functionalisation was found to be hydrochloric acid.Conclusion:Due to the very distinct patterns shown by the FT-IR spectrum of the HNO3-FAC after a fair comparison with others,it allows for a larger number of surface functional groups which will definitely enhance the stability of the enzyme lipase.
基金supported by the Program of Shandong Modern Agricultural Technology and Industry System–Cultivation and Soil Fertilizer(SDAIT0107)the Major Application Technology Innovation Projects in Shandong Province and the Key Research and Development Projects of Shandong Province.
文摘In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer on plant nitrogen utilization is not clear.A study was,therefore,conducted to explore the activities and gene expression of key enzymes for nitrogen assimilation and the gene expression of nitrogen transporters in wheat after the application of synergistic fertilizer.Soil column experiment was set up in Qingdao Agricultural University experimental base from October 2018 to June 2019.Maleic acid and itaconic acid were copolymerized with acrylic acid as cross-linking monomer to make a fluid gel,which was sprayed on the fertilizer surface to make nitrogen and phosphorus synergistic fertilizer.A total of 6 treatments was set according to different nitrogen and phosphorus fertilizer ratios:(1)100%common nitrogen fertilizer+100%common phosphate fertilizer(2)70%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(3)100%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(4)100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(5)70%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(6)100%commercial nitrogen synergistic fertilizer+100%commercial phosphorus synergistic fertilizer.The results are as follows:(1)the enzyme activities of wheat plants under synergistic fertilizer condition were higher than those under ordinary fertilizer,except under the treatment that nitrogen and phosphorus synergistic fertilizer were both reduced;(2)the expression level of the genes under the treatment“100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer”was significantly higher than those in other treatments.Combined with the higher performance of nitrogen concentration in various parts of the plant under the condition of applying synergistic fertilizer,this study indicated that the application of synergistic fertilizer can improve the nitrogen metabolism of the plant by increasing the nitrogen level in the rhizosphere soil,inducing the expression of nitrogen transporter genes and key assimilation enzymes genes.
文摘Crop rotation periodicity has always been one of the research focuses currently. In this study, the physicochemical properties, nutrient contents and enzyme activities were investigated in soils from rice-cherry tomato rotation for one year (1a), three years (3a), five years (5a), seven years (7a) and ten years (10a), respectively. The major objective was to analyze the optimal rotation years of rice-cherry tomato from soil perspective, so as to provide theoretical basis for effectively avoiding continuous cropping obstacles of cherry tomato via studying the response characteristics of soil physicochemical properties, nutrient contents and enzyme activities to planting years of rice-cherry tomato rotation system. The results were as follows: 1) Soil pH value was increased year by year during 1a to 5a, reached the highest value 5.32 at 5a. However, soil acidity was sharply enhanced during 7a to 10a (P P •kg<sup>-1</sup> at 5a. 3) The content of soil available phosphorus was increased year by year with increasing of crop rotation years, and increased by 110% to 173% during 3a to 10a (P P P < 0.05). In conclusion, long-term single rotation pattern of rice-cherry tomato would aggravate soil acidification, prompt soil nutrient imbalance and reduce soil enzyme activity. 5a to 7a would be the appropriate rotation period for rice-cherry tomato, or else it would reduce soil quality, resulting in a new continuous cropping obstacle of cherry tomato.
基金supported by the Key Research and Development Program of Zhejiang Province,China(2022C02008)the National Natural Science Foundation of China(31401343)+1 种基金the earmarked fund for China Agriculture Research System(CARS-01)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAASZDRW202001)。
文摘Soil microorganisms play important roles in nitrogen transformation. The aim of this study was to characterize changes in the activity of nitrogen transformation enzymes and the abundance of nitrogen function genes in rhizosphere soil aerated using three different methods(continuous flooding(CF), continuous flooding and aeration(CFA), and alternate wetting and drying(AWD)). The abundances of amoA ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB), nirS, nirK, and nifH genes, and the activities of urease, protease, ammonia oxidase, nitrate reductase, and nitrite reductase were measured at the tillering(S1), heading(S2), and ripening(S3) stages. We analyzed the relationships of the aforementioned microbial activity indices, in addition to soil microbial biomass carbon(MBC) and soil microbial biomass nitrogen(MBN), with the concentration of soil nitrate and ammonium nitrogen. The abundance of nitrogen function genes and the activities of nitrogen invertase in rice rhizosphere soil were higher at S2 compared with S1 and S3 in all treatments. AWD and CFA increased the abundance of amoA and nifH genes, and the activities of urease, protease, and ammonia oxidase, and decreased the abundance of nirS and nirK genes and the activities of nitrate reductase and nitrite reductase, with the effect of AWD being particularly strong. During the entire growth period, the mean abundances of the AOA amoA, AOB amoA, and nifH genes were 2.9, 5.8, and 3.0 higher in the AWD treatment than in the CF treatment, respectively, and the activities of urease, protease, and ammonia oxidase were 1.1, 0.5, and 0.7 higher in the AWD treatment than in the CF treatment, respectively. The abundances of the nirS and nirK genes, and the activities of nitrate reductase and nitrite reductase were 73.6, 84.8, 10.3 and 36.5% lower in the AWD treatment than in the CF treatment, respectively. The abundances of the AOA amoA, AOB amoA, and nifH genes were significantly and positively correlated with the activities of urease, protease, and ammonia oxidase, and the abundances of the nirS and nirK genes were significantly positively correlated with the activities of nitrate reductase. All the above indicators were positively correlated with soil MBC and MBN. In sum, microbial activity related to nitrogen transformation in rice rhizosphere soil was highest at S2. Aeration can effectively increase the activity of most nitrogen-converting microorganisms and MBN, and thus promote soil nitrogen transformation.
