Eight-month-old Wulong geese were fed with the diet with different proportions of Leymus chiesensis at the same energy and protein level. The activities of plasma Alkaline Phosphatase （AKP）, Acid Phosphatase （ACP）...Eight-month-old Wulong geese were fed with the diet with different proportions of Leymus chiesensis at the same energy and protein level. The activities of plasma Alkaline Phosphatase （AKP）, Acid Phosphatase （ACP）, Choline Esterace （CHE）, Lactic Dehydrogenase （LDH）, Glutamicoxalacetic Transaminase （GOT） and Glutamatepyruvate Transaminase （GPT） were determined and then their correlations with fiber digestibility and the apparent digestibility of Ca, R Met and Cys were analyzed. The results showed that the activity of AKP took on a significant downtrend as the increasing of Leymus chinensis proportion （P〈0.05）. There was a negative correlation between the AKP activity and the digestibility of crude fiber （CF）, neutral detergent fiber （NDF） and acid detergent fiber （ADF） （P〈0.05）. However, there was a significant positive correlation between the AKP activity and the apparent digestibility of Ca, Met and Cys （P〈0.05）. Moreover, the activities of the other five enzymes had no significant correlation with the digestibility of CF, NDF, ADF, and the apparent digestibility of Ca, Met and Cys （P〉0.05）.展开更多
To evaluate the influence of various Cr(Ⅵ) concentrations (0.05, 0.25, 0.50, 1.00 and 2.00 g/kg) on the activity of soil enzymes, the activities of catalase, polyphenol oxidase, dehydrogenase, alkaline phosphatase in...To evaluate the influence of various Cr(Ⅵ) concentrations (0.05, 0.25, 0.50, 1.00 and 2.00 g/kg) on the activity of soil enzymes, the activities of catalase, polyphenol oxidase, dehydrogenase, alkaline phosphatase in soils were investigated in the incubation experiment with a period of 35 d. The results indicate that all the tested Cr(Ⅵ) concentrations significantly inhibit dehydrogenase activity by over 70% after 35 d. The activity of alkaline phosphatase is slightly inhibited during the whole experiment except for on the day 7. Cr(Ⅵ) has no obvious effect on the activity of catalase in soil. On the contrary, Cr(Ⅵ) stimulates the activity of polyphenol oxidase. The results suggest that dehydrogenase activity can be used as an indicator for assessing the severity of chromium pollution.展开更多
In recent years,chiral inorganic nanomaterials have become promising candidates for applications in sensing,catalysis,biomedicine,and photonics.Plasmonic nanomaterials with an intrinsic chiral structure exhibit intrig...In recent years,chiral inorganic nanomaterials have become promising candidates for applications in sensing,catalysis,biomedicine,and photonics.Plasmonic nanomaterials with an intrinsic chiral structure exhibit intriguing geometry‑dependent optical chirality,which benefits the combination of plasmonic characteristics with chirality.Recent advances in the biomolecule‑directed geometric control of intrinsically chiral plasmonic nanomaterials have further provided great opportunities for their widespread applications in many emerging technological areas.In this review,we present the recent progress in biosensing using chiral inorganic nanomaterials,with a particular focus on electrochemical and enzyme‑mimicking catalytic approaches.This paper commences with a review of the basic tenets underlying chiral nanocatalysts,incorporating the chiral ligand‑induced mechanism and the architectures of intrinsically chiral nanostructures.Additionally,it methodically expounds upon the applications of chiral nanocatalysts in the realms of electrochemical biosensing and enzyme‑mimicking catalytic biosensing respectively.Conclusively,it proffers a prospective view of the hurdles and prospects that accompany the deployment of chiral nanoprobes for nascent biosensing applications.By rational design of the chiral nanoprobes,it is envisioned that biosensing with increasing sensitivity and resolution toward the single‑molecule level can be achieved,which will substantially promote sensing applications in many emerging interdisciplinary areas.展开更多
UBE2O is a distinctive ubiquitin-conjugating enzyme characterized by its large size(1292 residues)and dual E2/E3 enzymatic activities,enabling diverse ubiquitylation types.Unlike typical E2 enzymes(150~200 residues),U...UBE2O is a distinctive ubiquitin-conjugating enzyme characterized by its large size(1292 residues)and dual E2/E3 enzymatic activities,enabling diverse ubiquitylation types.Unlike typical E2 enzymes(150~200 residues),UBE2O’s multifunctionality allows it to regulate substrate degradation,subcellular localization,and functional modulation.Emerging studies highlight its critical roles in protein quality control,erythroid differentiation,metabolic regulation,and maintenance of circadian rhythm.Dysregulation of UBE2O is implicated in various diseases,including cancers,neurodegenerative disorders,and metabolic diseases.This review extensively discusses the unique structural features,diverse biological functions,and pathological roles of UBE2O,as well as its therapeutic potential for associated diseases.展开更多
Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration ...Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Iα-loop-helix Iβmotif which corresponds to helix I of other P 450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,theγ-domain.The structure reveals a homodimer in which theγ-domain of one molecule interacts with theβ-domain of another.The plane of heme group makes an angle of approximately 40°with the helix Iα-loop-helix Iβmotif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recognition.Phe-301,Ser-303 and Gly-305 from the helix Iα-loop-helix Iβmotif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.展开更多
In order to explore the remediation effects of lignite and biochar on Zn-contaminated soil,this experiment studied the impacts of adding lignite and biochar on soil respiration,soil enzyme activity,and organic carbon ...In order to explore the remediation effects of lignite and biochar on Zn-contaminated soil,this experiment studied the impacts of adding lignite and biochar on soil respiration,soil enzyme activity,and organic carbon in Zn-contaminated soil through soil culture experiments,which provided a theoretical basis for the remediation and improvement as well as for the development and utilization of Zn-contaminated soil.The study was an L8(4×2^(2))orthogonal experimental design with eight treatments,in which there were four levels of Zn contamination concentration(Z0:0;Z1:125 mg•kg^(-1);Z2:250 mg•kg^(-1);Z3:500 mg•kg^(-1)),low-Zn(125-250 mg•kg^(-1))and high-Zn(500 mg•kg^(-1)),two levels of lignite(H0:0;H1:13.33 g•kg^(-1)),two levels of biochar(C0:0;C1:3.33 g•kg^(-1)),with four replicates per treatment.The results showed that lignite or biochar and their interaction had extremely significant effects on both respiration rate and accumulation in Zn-contaminated soil.Among the high Zn-contaminated treatments,the mixed application of lignite and biochar(Z3H1C1 treatment)had the fastest soil respiration rate and the highest soil respiration accumulation.Lignite,biochar and their interaction had significant or extremely significant effects on sucrase,catalase and polyphenol oxidase activities in Zn-contaminated soil.Among the high Zn-contaminated treatments(Z3),the addition of biochar alone had the most significant effects on the increase of soil sucrase and catalase enzyme activities,while the mixed application of lignite and biochar had the most significant effects on the increase of soil polyphenol oxidase activity.Lignite,biochar and their interaction had significant or extremely significant effects on the total organic carbon,active organic carbon and microbial carbon content of Zn-contaminated soils.Soil total organic carbon content in general peaked at day 80.Among the high Zn-contaminated treatments,the addition of biochar alone had the most significant effects on the total organic carbon content of the soil,while the mixed application of lignite and biochar had the most significant effect on the microbiomass carbon content.展开更多
The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the conc...The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the concentrations of various organic carbon components in degraded mollisol.This study used a completely randomized factorial design with three application rates of organic fertilizer(M0:0,M1:13.64 g·kg^(-1),M2:27.27 g·kg^(-1))and biochar(C0:0,C1:1.36 g·kg^(-1),C2:2.73 g·kg^(-1)),resulting in nine treatments with four replicates each.Soil CO_(2) flux,organic carbon fractions including the total,active and microbial biomass carbon,and enzyme activities(sucrase,catalase and polyphenol oxidase)were measured over 120 days.Results indicated that the factors and their interactions significantly influenced all measured parameters.Soil respiration peaked at day 15,with M1C2 treatment exhibiting a rate of 10.90-fold higher than the control.The concentrations of the total,active and microbial biomass organic carbon reached maximum values on days 60,30 and 80,respectively.Notably,M2C1 treatment yielded the highest total organic carbon(86.35%increase)and microbial biomass carbon(17.84%increase).Enzyme activities were significantly enhanced,with the highest catalase activity observed for M0C2 treatment(10.14%increase).These results demonstrated that the co-application of organic fertilizer and biochar was a effective strategy for improving soil biological health and promoting carbon sequestration in degraded mollisol.The treatment combining a high rate of organic fertilizer with a low rate of biochar(M2C1)was identified as the most promising amendment strategy for fertility restoration.展开更多
Pectins had been extracted from shaddock raw material with 0.01 mol·L^-1 HCI and with three enzymic preparations including cellulase from aspergillus oryzaei.β -glucosidase from almonds and protopectinases-T, a ...Pectins had been extracted from shaddock raw material with 0.01 mol·L^-1 HCI and with three enzymic preparations including cellulase from aspergillus oryzaei.β -glucosidase from almonds and protopectinases-T, a protopectin-solubilizing enzyme, which did not degrade polygalacturonic acid, The effects of enzymic and acid soluhilization of pectin from shaddock materials were compared, The yield of pectin preparations, degree of acetylation, gelling strength, molecular weight and viscosity were determined. Enzymic methods of extraction gave much bigger yields of pectic substances. Compared with the pectin extracted with hydrochloric acid, all the samples derived from shaddock raw material with enzymic preparations had a significant lower D-galacturonic acid content.展开更多
Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon （MB...Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon （MBC） and nitrogen （MBN） were studied. Six treatments of soybean-soybean, soybean-maize, soybean-mixed, maize-soybean, maize-maize and maize-mixed were conducted in pots. Results showed that catalase activity and invertase activity of maize-maize were the highest and significantly different from those of the other treatments except maize-soybean; soil polyphenol oxidase activity of soybean-maize was the highest, and reached significant level among the other treatments, but there was no significant difference of urease activity among treatment soils; MBC of maize-maize soil and MBN of maize-mixed soil reached the highest and significant levels compared with other treatments; MBC and C/N ratio had positive and very significant correlations with soil catalase activity and invertase activity, respectively. Therefore, different cropping patterns could affect rhizosphere soil enzyme activities and soil MBC and MBN, which influenced soil carbon and nitrogen mineralization.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
Drying technology of angiotensin converting enzyme （ACE） inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying a...Drying technology of angiotensin converting enzyme （ACE） inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying and freeze drying （P〉0.05）. Spay drying was the best drying process for practical industry production. The inlet temperature ranged from 140℃ to 160℃ and the exit temperature ranged from 70 ℃ to 90 ℃ during the spay drying process. Under the optimal conditions, scale-up of angiotensin converted enzyme inhibitory peptide from 1 L to 10 L and the experiment was successively conducted. Peptide yield was 29% and half inhibitory concentration （IC50） was 0.53 g. L^-1.展开更多
Iron(Ⅱ) tetrasulfophthalocyanine(FeTSPc) ,as a novel mimetic enzyme of peroxidase,was used in the synthesis of a conducting polyaniline(PANI) /sodium dodecylsulfate(SDS) complex in SDS aqueous micellar solutions. The...Iron(Ⅱ) tetrasulfophthalocyanine(FeTSPc) ,as a novel mimetic enzyme of peroxidase,was used in the synthesis of a conducting polyaniline(PANI) /sodium dodecylsulfate(SDS) complex in SDS aqueous micellar solutions. The effects of pH,concentrations of aniline,SDS and H2O2,and reaction time on polymerization of aniline were studied in this case as shown by UV-Vis absorption spectroscopy. The results show that a wide range of pH(0.5-4.0) is required to produce the conducting PANI,and the optimal pH is 1.0 in SDS micelle. The optimal concentrations of aniline,SDS and H2O2 in feed,and reaction time in this case for the production of conducting PANI are respectively 10 mmol/L,10 mmol/L,25 mmol/L,and 15 h. FT-IR spectrum,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analysis confirm the thermal stability and electroactive form of PANI.展开更多
The current study aims to evaluate the dynamic response of stabilized cohesive soil using an enzymatic preparation in terms of resilient modulus.We ran a series of resilient modulus testing according to AASHTO T307 on...The current study aims to evaluate the dynamic response of stabilized cohesive soil using an enzymatic preparation in terms of resilient modulus.We ran a series of resilient modulus testing according to AASHTO T307 on three types of cohesive soil treated with an enzymatic preparation to investigate its potential on roads construction.The results show significant improvement in the resilient modulus values,estimated at 1.4 to 4.4 times that observed for the untreated soil.Because of the complexity in conducting the resilient modulus measurement,we did a regression analysis to produce reliable correlation formula to predict the resilient modulus for untreated and stabilised soil samples involving stress state.The resilient modulus values for the subgrade materials at the anticipated field stresses were determined using a universal model.The enzymatic preparation was applied in pavement of a sample road and evaluated using the plate load test.SEM analysis for soil samples shows improvement in the soil compaction via reduction of voids between soil particles.XRD analysis shows no major structural changes in the treated soils.The enzymatic preparation contains 43 mg/mL of proteins.We used the SDS-PAGE(sodium dodecyl sulphate polyacrylamide gel electrophoresis)technique to identify the main protein components;however,the presence of interfering materials(surfactants)hinders the separation.展开更多
The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw retur...The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.展开更多
Etrazine is one of the most widely used herbicides in China and the world. Acute and chronic toxicity tests werc carried out to assess the possible toxicity effect of atrazine on crucian carp （Carassius auratus）. Re...Etrazine is one of the most widely used herbicides in China and the world. Acute and chronic toxicity tests werc carried out to assess the possible toxicity effect of atrazine on crucian carp （Carassius auratus）. Results showed that 96 h LC,. of atrazine to Carassius auratus was 105.94 mg. L-1. The enzyme activities of superoxide dismutase （SOD）, catalase （CAT） and glutathione-S-transferases （GST） in kidney of Carassius auratus were all influenced by atraizine, and CAT was more sensitive to atrazine compared with SOD and GST. Atrazine residues in kidney of Carassius aura/us reached the stable state at day 19, and the bioaccumulation factors （BAF） of atrazine in kidney of Carassius auratus treated with 1.0 mg. L-1 and 10.0 mg. L-1 atrazine were 8.3 and 4.4, respectively. The research demonstrated that atrazine could cause oxidative stress to fish kidney, but atrazine was not easy to accumulate in Carassius auratus kidney, and the antioxidant enzymes could be used as biomarker to the early detection of pollution.展开更多
Both conventional and microchip-based capillary electrophoresis(CE) technologies have been used for the analysis of enzymes. Practical procedures of using CE to determine the Km and Vmax values of an enzyme have been ...Both conventional and microchip-based capillary electrophoresis(CE) technologies have been used for the analysis of enzymes. Practical procedures of using CE to determine the Km and Vmax values of an enzyme have been developed. By studying the inhibition to the enzyme, it is possible to select a suitable drug candidate. When compared with the conventional CE method, single lane microchip-based method can improve the speed for the assay three times. By using multiple lane-based microchip, the speed can be further increased.展开更多
The synthesis of dipeptide AcPheLeuNH2 catalyzed by immobilized pancreatic lipase was carried out in a two- liquid-phase hollow-fiber membrane reactor, operated in a batch mode. Kinetic properties of free and immobili...The synthesis of dipeptide AcPheLeuNH2 catalyzed by immobilized pancreatic lipase was carried out in a two- liquid-phase hollow-fiber membrane reactor, operated in a batch mode. Kinetic properties of free and immobilized enzyme, partition behavior between aqueous buffer phase and organic solvent phase, and effective diffusion coefficients of substrates and products through the membrane were investigated respectively. Based on the preliminary experimental results, the performance of the enzyme membrane reactor, which is evaluated by the purity and the yield, is discussed.展开更多
文摘Eight-month-old Wulong geese were fed with the diet with different proportions of Leymus chiesensis at the same energy and protein level. The activities of plasma Alkaline Phosphatase （AKP）, Acid Phosphatase （ACP）, Choline Esterace （CHE）, Lactic Dehydrogenase （LDH）, Glutamicoxalacetic Transaminase （GOT） and Glutamatepyruvate Transaminase （GPT） were determined and then their correlations with fiber digestibility and the apparent digestibility of Ca, R Met and Cys were analyzed. The results showed that the activity of AKP took on a significant downtrend as the increasing of Leymus chinensis proportion （P〈0.05）. There was a negative correlation between the AKP activity and the digestibility of crude fiber （CF）, neutral detergent fiber （NDF） and acid detergent fiber （ADF） （P〈0.05）. However, there was a significant positive correlation between the AKP activity and the apparent digestibility of Ca, Met and Cys （P〈0.05）. Moreover, the activities of the other five enzymes had no significant correlation with the digestibility of CF, NDF, ADF, and the apparent digestibility of Ca, Met and Cys （P〉0.05）.
基金Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of ChinaProject(2008SK2007) supported by the Key Program of Science and Technology of Hunan Province, China
文摘To evaluate the influence of various Cr(Ⅵ) concentrations (0.05, 0.25, 0.50, 1.00 and 2.00 g/kg) on the activity of soil enzymes, the activities of catalase, polyphenol oxidase, dehydrogenase, alkaline phosphatase in soils were investigated in the incubation experiment with a period of 35 d. The results indicate that all the tested Cr(Ⅵ) concentrations significantly inhibit dehydrogenase activity by over 70% after 35 d. The activity of alkaline phosphatase is slightly inhibited during the whole experiment except for on the day 7. Cr(Ⅵ) has no obvious effect on the activity of catalase in soil. On the contrary, Cr(Ⅵ) stimulates the activity of polyphenol oxidase. The results suggest that dehydrogenase activity can be used as an indicator for assessing the severity of chromium pollution.
文摘In recent years,chiral inorganic nanomaterials have become promising candidates for applications in sensing,catalysis,biomedicine,and photonics.Plasmonic nanomaterials with an intrinsic chiral structure exhibit intriguing geometry‑dependent optical chirality,which benefits the combination of plasmonic characteristics with chirality.Recent advances in the biomolecule‑directed geometric control of intrinsically chiral plasmonic nanomaterials have further provided great opportunities for their widespread applications in many emerging technological areas.In this review,we present the recent progress in biosensing using chiral inorganic nanomaterials,with a particular focus on electrochemical and enzyme‑mimicking catalytic approaches.This paper commences with a review of the basic tenets underlying chiral nanocatalysts,incorporating the chiral ligand‑induced mechanism and the architectures of intrinsically chiral nanostructures.Additionally,it methodically expounds upon the applications of chiral nanocatalysts in the realms of electrochemical biosensing and enzyme‑mimicking catalytic biosensing respectively.Conclusively,it proffers a prospective view of the hurdles and prospects that accompany the deployment of chiral nanoprobes for nascent biosensing applications.By rational design of the chiral nanoprobes,it is envisioned that biosensing with increasing sensitivity and resolution toward the single‑molecule level can be achieved,which will substantially promote sensing applications in many emerging interdisciplinary areas.
基金Supported by Special Projects in Key Areas for Guangdong Provincial Colleges and Universities (No.2021ZDZX2009)Guangzhou Medical University Discipline Construction Funds (Basic Medicine)(No.JCXKJS2022A05)。
文摘UBE2O is a distinctive ubiquitin-conjugating enzyme characterized by its large size(1292 residues)and dual E2/E3 enzymatic activities,enabling diverse ubiquitylation types.Unlike typical E2 enzymes(150~200 residues),UBE2O’s multifunctionality allows it to regulate substrate degradation,subcellular localization,and functional modulation.Emerging studies highlight its critical roles in protein quality control,erythroid differentiation,metabolic regulation,and maintenance of circadian rhythm.Dysregulation of UBE2O is implicated in various diseases,including cancers,neurodegenerative disorders,and metabolic diseases.This review extensively discusses the unique structural features,diverse biological functions,and pathological roles of UBE2O,as well as its therapeutic potential for associated diseases.
文摘Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Iα-loop-helix Iβmotif which corresponds to helix I of other P 450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,theγ-domain.The structure reveals a homodimer in which theγ-domain of one molecule interacts with theβ-domain of another.The plane of heme group makes an angle of approximately 40°with the helix Iα-loop-helix Iβmotif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recognition.Phe-301,Ser-303 and Gly-305 from the helix Iα-loop-helix Iβmotif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.
基金Supported by the Special Fund for Agro-scientific Research in Public Interest in China(201503119-06-01)。
文摘In order to explore the remediation effects of lignite and biochar on Zn-contaminated soil,this experiment studied the impacts of adding lignite and biochar on soil respiration,soil enzyme activity,and organic carbon in Zn-contaminated soil through soil culture experiments,which provided a theoretical basis for the remediation and improvement as well as for the development and utilization of Zn-contaminated soil.The study was an L8(4×2^(2))orthogonal experimental design with eight treatments,in which there were four levels of Zn contamination concentration(Z0:0;Z1:125 mg•kg^(-1);Z2:250 mg•kg^(-1);Z3:500 mg•kg^(-1)),low-Zn(125-250 mg•kg^(-1))and high-Zn(500 mg•kg^(-1)),two levels of lignite(H0:0;H1:13.33 g•kg^(-1)),two levels of biochar(C0:0;C1:3.33 g•kg^(-1)),with four replicates per treatment.The results showed that lignite or biochar and their interaction had extremely significant effects on both respiration rate and accumulation in Zn-contaminated soil.Among the high Zn-contaminated treatments,the mixed application of lignite and biochar(Z3H1C1 treatment)had the fastest soil respiration rate and the highest soil respiration accumulation.Lignite,biochar and their interaction had significant or extremely significant effects on sucrase,catalase and polyphenol oxidase activities in Zn-contaminated soil.Among the high Zn-contaminated treatments(Z3),the addition of biochar alone had the most significant effects on the increase of soil sucrase and catalase enzyme activities,while the mixed application of lignite and biochar had the most significant effects on the increase of soil polyphenol oxidase activity.Lignite,biochar and their interaction had significant or extremely significant effects on the total organic carbon,active organic carbon and microbial carbon content of Zn-contaminated soils.Soil total organic carbon content in general peaked at day 80.Among the high Zn-contaminated treatments,the addition of biochar alone had the most significant effects on the total organic carbon content of the soil,while the mixed application of lignite and biochar had the most significant effect on the microbiomass carbon content.
基金Supported by the Special Fund for Agro-scientific Research in Public Interest in China(201503119-06-01)。
文摘The objective of this incubation study was to comprehensively evaluate the effects of organic fertilizer and biochar,both individually and in combination,on soil respiration dynamics,key enzyme activities and the concentrations of various organic carbon components in degraded mollisol.This study used a completely randomized factorial design with three application rates of organic fertilizer(M0:0,M1:13.64 g·kg^(-1),M2:27.27 g·kg^(-1))and biochar(C0:0,C1:1.36 g·kg^(-1),C2:2.73 g·kg^(-1)),resulting in nine treatments with four replicates each.Soil CO_(2) flux,organic carbon fractions including the total,active and microbial biomass carbon,and enzyme activities(sucrase,catalase and polyphenol oxidase)were measured over 120 days.Results indicated that the factors and their interactions significantly influenced all measured parameters.Soil respiration peaked at day 15,with M1C2 treatment exhibiting a rate of 10.90-fold higher than the control.The concentrations of the total,active and microbial biomass organic carbon reached maximum values on days 60,30 and 80,respectively.Notably,M2C1 treatment yielded the highest total organic carbon(86.35%increase)and microbial biomass carbon(17.84%increase).Enzyme activities were significantly enhanced,with the highest catalase activity observed for M0C2 treatment(10.14%increase).These results demonstrated that the co-application of organic fertilizer and biochar was a effective strategy for improving soil biological health and promoting carbon sequestration in degraded mollisol.The treatment combining a high rate of organic fertilizer with a low rate of biochar(M2C1)was identified as the most promising amendment strategy for fertility restoration.
基金The Key Program of Science and Technology Office of Hunan Province (00KNY1010)
文摘Pectins had been extracted from shaddock raw material with 0.01 mol·L^-1 HCI and with three enzymic preparations including cellulase from aspergillus oryzaei.β -glucosidase from almonds and protopectinases-T, a protopectin-solubilizing enzyme, which did not degrade polygalacturonic acid, The effects of enzymic and acid soluhilization of pectin from shaddock materials were compared, The yield of pectin preparations, degree of acetylation, gelling strength, molecular weight and viscosity were determined. Enzymic methods of extraction gave much bigger yields of pectic substances. Compared with the pectin extracted with hydrochloric acid, all the samples derived from shaddock raw material with enzymic preparations had a significant lower D-galacturonic acid content.
基金Supported by the Scientific Research Foundation for Doctor of Northeast Agricultural UniversityInnovative Team Fund of Northeast Agricultural University
文摘Through the pot experiment, the effects of different cropping patterns of soybean and maize seedlings on rhizosphere soil urease, catalase, polyphenol oxidase and invertase activities and microbial biomass carbon （MBC） and nitrogen （MBN） were studied. Six treatments of soybean-soybean, soybean-maize, soybean-mixed, maize-soybean, maize-maize and maize-mixed were conducted in pots. Results showed that catalase activity and invertase activity of maize-maize were the highest and significantly different from those of the other treatments except maize-soybean; soil polyphenol oxidase activity of soybean-maize was the highest, and reached significant level among the other treatments, but there was no significant difference of urease activity among treatment soils; MBC of maize-maize soil and MBN of maize-mixed soil reached the highest and significant levels compared with other treatments; MBC and C/N ratio had positive and very significant correlations with soil catalase activity and invertase activity, respectively. Therefore, different cropping patterns could affect rhizosphere soil enzyme activities and soil MBC and MBN, which influenced soil carbon and nitrogen mineralization.
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 Scientific Research Foundation for Young Scholars of Heilongjiang Province of China (QC07C25)The National High Technology Research and Development Program of China (2008AA10Z315)
文摘Drying technology of angiotensin converting enzyme （ACE） inhibitory peptides derived from bovine casein was investigated. No significance was observed on ACE inhibitory activity of products prepared by spay drying and freeze drying （P〉0.05）. Spay drying was the best drying process for practical industry production. The inlet temperature ranged from 140℃ to 160℃ and the exit temperature ranged from 70 ℃ to 90 ℃ during the spay drying process. Under the optimal conditions, scale-up of angiotensin converted enzyme inhibitory peptide from 1 L to 10 L and the experiment was successively conducted. Peptide yield was 29% and half inhibitory concentration （IC50） was 0.53 g. L^-1.
基金Project(07JJ6020) supported by the Hunan Provincial Natural Science Foundation of ChinaProject(2007-24-3) supported by the Huaihua Key Science and Technology Program, China
文摘Iron(Ⅱ) tetrasulfophthalocyanine(FeTSPc) ,as a novel mimetic enzyme of peroxidase,was used in the synthesis of a conducting polyaniline(PANI) /sodium dodecylsulfate(SDS) complex in SDS aqueous micellar solutions. The effects of pH,concentrations of aniline,SDS and H2O2,and reaction time on polymerization of aniline were studied in this case as shown by UV-Vis absorption spectroscopy. The results show that a wide range of pH(0.5-4.0) is required to produce the conducting PANI,and the optimal pH is 1.0 in SDS micelle. The optimal concentrations of aniline,SDS and H2O2 in feed,and reaction time in this case for the production of conducting PANI are respectively 10 mmol/L,10 mmol/L,25 mmol/L,and 15 h. FT-IR spectrum,elemental analysis,conductivity,cyclic voltammetry and thermogravimetric analysis confirm the thermal stability and electroactive form of PANI.
基金Project supported by the Academy of Scientific Research and Technology,ASRT,Cairo,Egypt
文摘The current study aims to evaluate the dynamic response of stabilized cohesive soil using an enzymatic preparation in terms of resilient modulus.We ran a series of resilient modulus testing according to AASHTO T307 on three types of cohesive soil treated with an enzymatic preparation to investigate its potential on roads construction.The results show significant improvement in the resilient modulus values,estimated at 1.4 to 4.4 times that observed for the untreated soil.Because of the complexity in conducting the resilient modulus measurement,we did a regression analysis to produce reliable correlation formula to predict the resilient modulus for untreated and stabilised soil samples involving stress state.The resilient modulus values for the subgrade materials at the anticipated field stresses were determined using a universal model.The enzymatic preparation was applied in pavement of a sample road and evaluated using the plate load test.SEM analysis for soil samples shows improvement in the soil compaction via reduction of voids between soil particles.XRD analysis shows no major structural changes in the treated soils.The enzymatic preparation contains 43 mg/mL of proteins.We used the SDS-PAGE(sodium dodecyl sulphate polyacrylamide gel electrophoresis)technique to identify the main protein components;however,the presence of interfering materials(surfactants)hinders the separation.
基金Supported by the National Key Research and Development Plan Project(2016YFD0300909-04)。
文摘The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.
基金Supported by the Natural Science Foundation of China (30170162)Wuxi Science and Technology Bureau Foundation (CL045001)
文摘Etrazine is one of the most widely used herbicides in China and the world. Acute and chronic toxicity tests werc carried out to assess the possible toxicity effect of atrazine on crucian carp （Carassius auratus）. Results showed that 96 h LC,. of atrazine to Carassius auratus was 105.94 mg. L-1. The enzyme activities of superoxide dismutase （SOD）, catalase （CAT） and glutathione-S-transferases （GST） in kidney of Carassius auratus were all influenced by atraizine, and CAT was more sensitive to atrazine compared with SOD and GST. Atrazine residues in kidney of Carassius aura/us reached the stable state at day 19, and the bioaccumulation factors （BAF） of atrazine in kidney of Carassius auratus treated with 1.0 mg. L-1 and 10.0 mg. L-1 atrazine were 8.3 and 4.4, respectively. The research demonstrated that atrazine could cause oxidative stress to fish kidney, but atrazine was not easy to accumulate in Carassius auratus kidney, and the antioxidant enzymes could be used as biomarker to the early detection of pollution.
文摘Both conventional and microchip-based capillary electrophoresis(CE) technologies have been used for the analysis of enzymes. Practical procedures of using CE to determine the Km and Vmax values of an enzyme have been developed. By studying the inhibition to the enzyme, it is possible to select a suitable drug candidate. When compared with the conventional CE method, single lane microchip-based method can improve the speed for the assay three times. By using multiple lane-based microchip, the speed can be further increased.
基金Supported by the National Natural Science Foundation of China andExtraction Separation branch of United Chemical Engineeing
文摘The synthesis of dipeptide AcPheLeuNH2 catalyzed by immobilized pancreatic lipase was carried out in a two- liquid-phase hollow-fiber membrane reactor, operated in a batch mode. Kinetic properties of free and immobilized enzyme, partition behavior between aqueous buffer phase and organic solvent phase, and effective diffusion coefficients of substrates and products through the membrane were investigated respectively. Based on the preliminary experimental results, the performance of the enzyme membrane reactor, which is evaluated by the purity and the yield, is discussed.
