Alfalfa （Medicago sativa L.） is an important forage crop in the world and it is of great signiifcance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene...Alfalfa （Medicago sativa L.） is an important forage crop in the world and it is of great signiifcance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene （OsAPX2） was introduced into alfalfa using Agrobacterium tumefaciens-mediated transformation with marker gene bar. The different T-DNA insertions in T1 transgenic alfalfa were identiifed by Southern hybridization. Three independent T2 transgenic lines were selected for stress analysis and the results showed that all of them were salt tolerant compared with wild-type plants. The transgenic plants had low levels of H2O2, malondialdehyde and relative electrical conductivity under salt and drought stresses. Moreover, the contents of chlorophyll and proline, and APX activity were high in transgenic plants under salt and drought stresses. Taken together, the overexpression of OsAPX2 enhances salt tolerance in alfalfa through scavenging reactive oxygen species.展开更多
Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two...Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P < 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P < 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P < 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P < 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.展开更多
The vitamin C（VC） in crops was successfully determined using ascorbate oxidase（AO） electrochemical biosensor based on the biocompatible poly（3,4-ethylenedioxythiophene）（PEDOT） matrices,which was easily prepare...The vitamin C（VC） in crops was successfully determined using ascorbate oxidase（AO） electrochemical biosensor based on the biocompatible poly（3,4-ethylenedioxythiophene）（PEDOT） matrices,which was easily prepared by one-step electrodeposition technique in ionic liquid microemulsions.The fabricated biosensor displayed excellent bioelectrocatalytic performance to the oxidation of VC,wide linear range,low detection limit,fast response time,good operational and storage stability,the good results of the determination of VC in vegetable crops indicated that the fabricated biosensor will be a good candidate for the physiological and biochemical studies of crops in near future.展开更多
Apoplastic ascorbate oxidases(AOs)play a critical role in reactive oxygen species(RoS)-mediated innate host immunity by regulating the apoplast redox state.To date,little is known about how apoplastic effectors of the...Apoplastic ascorbate oxidases(AOs)play a critical role in reactive oxygen species(RoS)-mediated innate host immunity by regulating the apoplast redox state.To date,little is known about how apoplastic effectors of the riceblast fungus Magnaportheoryzaemodulate the apoplast redox state of rice to subvert plant immunity.In this study,we demonstrated that M.oryzae MoAo1 is an Ao that plays a role in virulence by modulating the apoplast redox status of rice cells.We showed that MoAo1 inhibits the activity of rice OsAO3and OsAO4,which also regulate the apoplast redox status and plant immunity.In addition,we found that MoAo1,OsAO3,andOsAO4 allexhibit polymorphic variations whosevaried interactions orchestrate pathogen virulence and rice immunity.Taken together,our results reveal a critical role for extracellular redox enzymes during rice blast infection and shed light on the importance of the apoplast redox state anditsregulation inplant-pathogeninteractions.展开更多
The biocompatiable and low-toxic poly（thiophene-3-aeetic acid） （PTAA） matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-metbylimidazolium hexafluorophosphate （BmimPF6） in comparison with the e...The biocompatiable and low-toxic poly（thiophene-3-aeetic acid） （PTAA） matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-metbylimidazolium hexafluorophosphate （BmimPF6） in comparison with the electrosynthesis of PTAA matrix in acetonitrile （ACN）. Ascorbate oxidase （AO） was used as a model for the development and application of biosensor. Vitamin C （VC） biosensors were facilely fabricated by the covalent immobilization of AO molecules on PTAA matrices electrosynthesized in ACN containing tetrabutylammonium tetrafluoroborate and BmimPF6, respectively. Electrochemical impedance spectroscopy, scanning electron microscopy and FTIR spectroscopy indicated that AO molecules were covalently immobilized on PTAA matrices. Parameters of the as-obtained biosensors such as working potential, pH and temperature have been optimized. The amperometric biosensor based on PTAA matrix electrosynthesized in BmimPF6 exhibited wider linear range, lower detection limit, higher sensitivity and bioaffinity, and better operational and storage stability than that electrosynthesized in ACN under optimal conditions. The as-obtained biosensor based on PTAA matrix electrosynthesized in BmimPF6 was employed for the detection of VC content in comme：rcial juices, and the result was close to the data given by manufacturers. Excellent results indicate that the PTAA matrix electrosynthesized in ionic liquid is a promising platform for the covalent immobilization of biologically-active species and the development of biosensors.展开更多
Nanomaterial-based artificial enzymes（nanozymes） have shown great potential for application in colori- metric sensing. In this paper, the nanocomposites of CeO2 and reduced graphene oxide（rCK）） were fabricated vi...Nanomaterial-based artificial enzymes（nanozymes） have shown great potential for application in colori- metric sensing. In this paper, the nanocomposites of CeO2 and reduced graphene oxide（rCK）） were fabricated via a one-pot hydrothermal process, in which CeO2 nanoparticles were well anchored on the surface of rGO. The prepared CeO2/rGO nanocomposites exhibited excellent catalytic activity for the oxidation of 3,3＇,5,5＇-tetramethylbenzidine（TMB） in the presence of 02. Compared with the individual CeO2 nanoparticles, the nanocomposites had a higher affinity and adsorptivity towards the substrate TMB, which was due to the combination of rGO. In addi- tion, based on the oxidase-like activity of CeO2/rGO nanocomposites, a facile and sensitive colormetric sensor for ascorbic acid（AA） was investigated. The detection limit of AA was low（0.15μmol/L） and the linear detection range was between 0.5μmol/L and 40μmol/L. Fttrthermore, the colorimetric system was used for the detection of AA in medicine and food analysis, such as tablets, beverage and milk powder.展开更多
基金supported by the National 973 Program of China (2014CB138700)
文摘Alfalfa （Medicago sativa L.） is an important forage crop in the world and it is of great signiifcance for the improvement of its salt tolerance. To improve salt tolerance in alfalfa, a rice ascorbate peroxidase gene （OsAPX2） was introduced into alfalfa using Agrobacterium tumefaciens-mediated transformation with marker gene bar. The different T-DNA insertions in T1 transgenic alfalfa were identiifed by Southern hybridization. Three independent T2 transgenic lines were selected for stress analysis and the results showed that all of them were salt tolerant compared with wild-type plants. The transgenic plants had low levels of H2O2, malondialdehyde and relative electrical conductivity under salt and drought stresses. Moreover, the contents of chlorophyll and proline, and APX activity were high in transgenic plants under salt and drought stresses. Taken together, the overexpression of OsAPX2 enhances salt tolerance in alfalfa through scavenging reactive oxygen species.
基金The State Key Development Program(2016YFD0501202)supported this study
文摘Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P < 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P < 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P < 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P < 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.
基金supported by NSFC(Nos50963002 and 51073074)Key Projects in the National Science& Technology Pillar Program in the Eleventh Five-year Plan Period of China(Nos2006BAD02A04 and 2006BAD01A01)Jiangxi Provincial Department of Education(NosGJJ11590 and GJJ10678)
文摘The vitamin C（VC） in crops was successfully determined using ascorbate oxidase（AO） electrochemical biosensor based on the biocompatible poly（3,4-ethylenedioxythiophene）（PEDOT） matrices,which was easily prepared by one-step electrodeposition technique in ionic liquid microemulsions.The fabricated biosensor displayed excellent bioelectrocatalytic performance to the oxidation of VC,wide linear range,low detection limit,fast response time,good operational and storage stability,the good results of the determination of VC in vegetable crops indicated that the fabricated biosensor will be a good candidate for the physiological and biochemical studies of crops in near future.
基金This research was supported by the China National Funds for Innovative Research Groups(31721004)the key program of the Natural Science Foundation of China(NSFC)(32030091)+3 种基金the NSFC Youth Program(31901832)Youth Program for Natural Science Foundation of Jiangsu Province(BK2019054)the program of NSFC-DFG(31861133017)the NSFC program(32172377)。
文摘Apoplastic ascorbate oxidases(AOs)play a critical role in reactive oxygen species(RoS)-mediated innate host immunity by regulating the apoplast redox state.To date,little is known about how apoplastic effectors of the riceblast fungus Magnaportheoryzaemodulate the apoplast redox state of rice to subvert plant immunity.In this study,we demonstrated that M.oryzae MoAo1 is an Ao that plays a role in virulence by modulating the apoplast redox status of rice cells.We showed that MoAo1 inhibits the activity of rice OsAO3and OsAO4,which also regulate the apoplast redox status and plant immunity.In addition,we found that MoAo1,OsAO3,andOsAO4 allexhibit polymorphic variations whosevaried interactions orchestrate pathogen virulence and rice immunity.Taken together,our results reveal a critical role for extracellular redox enzymes during rice blast infection and shed light on the importance of the apoplast redox state anditsregulation inplant-pathogeninteractions.
基金financially supported by the NSFC(Nos.50963002,51073074)Key Projects in the National Science & Technology Pillar Program in the Eleventh Five-year Plan Period(Nos.2006BAD02A04,2006BAD01A01)Jiangxi Provincial Department of Science and Technology(2006BAD01A01-2-5)
文摘The biocompatiable and low-toxic poly（thiophene-3-aeetic acid） （PTAA） matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-metbylimidazolium hexafluorophosphate （BmimPF6） in comparison with the electrosynthesis of PTAA matrix in acetonitrile （ACN）. Ascorbate oxidase （AO） was used as a model for the development and application of biosensor. Vitamin C （VC） biosensors were facilely fabricated by the covalent immobilization of AO molecules on PTAA matrices electrosynthesized in ACN containing tetrabutylammonium tetrafluoroborate and BmimPF6, respectively. Electrochemical impedance spectroscopy, scanning electron microscopy and FTIR spectroscopy indicated that AO molecules were covalently immobilized on PTAA matrices. Parameters of the as-obtained biosensors such as working potential, pH and temperature have been optimized. The amperometric biosensor based on PTAA matrix electrosynthesized in BmimPF6 exhibited wider linear range, lower detection limit, higher sensitivity and bioaffinity, and better operational and storage stability than that electrosynthesized in ACN under optimal conditions. The as-obtained biosensor based on PTAA matrix electrosynthesized in BmimPF6 was employed for the detection of VC content in comme：rcial juices, and the result was close to the data given by manufacturers. Excellent results indicate that the PTAA matrix electrosynthesized in ionic liquid is a promising platform for the covalent immobilization of biologically-active species and the development of biosensors.
基金Supported by the National Natural Science Foundation of China（No.21675008） and the Fundamental Research Funds for the Central Universities of China（No.JD1516）.
文摘Nanomaterial-based artificial enzymes（nanozymes） have shown great potential for application in colori- metric sensing. In this paper, the nanocomposites of CeO2 and reduced graphene oxide（rCK）） were fabricated via a one-pot hydrothermal process, in which CeO2 nanoparticles were well anchored on the surface of rGO. The prepared CeO2/rGO nanocomposites exhibited excellent catalytic activity for the oxidation of 3,3＇,5,5＇-tetramethylbenzidine（TMB） in the presence of 02. Compared with the individual CeO2 nanoparticles, the nanocomposites had a higher affinity and adsorptivity towards the substrate TMB, which was due to the combination of rGO. In addi- tion, based on the oxidase-like activity of CeO2/rGO nanocomposites, a facile and sensitive colormetric sensor for ascorbic acid（AA） was investigated. The detection limit of AA was low（0.15μmol/L） and the linear detection range was between 0.5μmol/L and 40μmol/L. Fttrthermore, the colorimetric system was used for the detection of AA in medicine and food analysis, such as tablets, beverage and milk powder.
