Maize/peanut intercropping system shows the significant yield advantage. Soil microbes play major roles in soil nutrient cycling and were affected by intercropping plants. This experiment was carried out to evaluate t...Maize/peanut intercropping system shows the significant yield advantage. Soil microbes play major roles in soil nutrient cycling and were affected by intercropping plants. This experiment was carried out to evaluate the changing of rhizosphere microbial community composition, and the relationship between microbial community and soil enzymatic activities, soil nutrients in maize/peanut intercropping system under the following three treatments: maize (Zea mays L.) and peanut (Arachis hypogaea L.) were intercropped without any separation (NS), by half separation (HS) using a nylon net (50 μm) and complete separation (CS) by using a plastic sheet, respectively. The soil microbial communities were assessed by phospholipid fatty acid (PLFA). We found that soil available nutrients (available nitrogen (Avail N) and available phosphorus (Avail P)) and enzymatic activities (soil urase and phosphomonoesterase) in both crops were improved in NS and HS treatments as compared to CS. Both bacterial and fungal biomasses in both crops were increased in NS followed by HS. Furthermore, Gram-positive bacteria (G+) in maize soils were significant higher in NS and HS than CS, while the Gram-negative (G-) was significant higher in peanut soil. The ratio of normal saturated to monounsaturated PLFAs was significantly higher in rhizosphere of peanut under CS treatment than in any other treatments, which is an indicator of nutrient stress. Redundancy analysis and cluster analysis of PLFA showed rhizospheric microbial community of NS and HS of both plants tended to be consistent. The urase and Avail N were higher in NS and HS of both plants and positively correlated with bacteria, fungi (F) and total PLFAs, while negatively correlated with G+/G- and NS/MS. The findings suggest that belowground interactions in maize/peanut intercropping system play important roles in changing the soil microbial composition and the dominant microbial species, which was closely related with the improving of soil available nutrients (N and P) and enzymatic activities.展开更多
Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathoge...Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.展开更多
A new stem rot disease is found to occur naturally on Arabidopsis plants in greenhouses of Fuzhou, China. In order to identify its pathogen, we conducted a series of fungal isolation and purification, plant reinoculat...A new stem rot disease is found to occur naturally on Arabidopsis plants in greenhouses of Fuzhou, China. In order to identify its pathogen, we conducted a series of fungal isolation and purification, plant reinoculation, and ascus and ascospore induction from the sclerotia. The isolate caused typical water-soaked lesions after reinoculation and produced sclerotia both on Arabidopsis plants and culture medium plates, and the sclerotia could be induced to produce discal apothecia and 8 binucleate ascospores per ascus. These disease symptom and fungal morphology data revealed that the fungus Sclerotinia sclerotiorum (Lib.) de Bary was the pathogen for Arabidopsis stem rot. To confirm this, we further amplified its large subunit ribosomal DNA (LSU rDNA) by polymerase chain reaction (PCR), and compared the sequence with the known LSU rDNA sequences in GenBank. The results show that the sequence shares the highest identities with the LSU rDNAs of different S. sclerotiorum strains. Taking all these data together, we concluded that the fungus that caused the Arabidopsis stem rot is S. sclerotiorum (Lib.) de Bary. This is the first report that Arabidopsis is naturally infected by S. sclerotiorum.展开更多
Atrazine is the second mostly used herbicide in USA,but low utilization ratio causes severe environmental problem,so controlled release system is highly needed in order to minimize the negative impact on environment.I...Atrazine is the second mostly used herbicide in USA,but low utilization ratio causes severe environmental problem,so controlled release system is highly needed in order to minimize the negative impact on environment.In this paper,a herbicide delivery system,atrazine-loaded poly(lactic-co-glycolic acid)(PLGA)nanoparticles(NPs)were prepared by forming an oilin-water emulsion using the emulsion-solvent evaporation method.By varying the preparation conditions of PLGA-NPs,such as sonication time,surfactant content,solvent fraction,and polymer content,the particle sizes of the PLGA-NPs were well controlled from 204 to 520 nm.The morphology and size distribution of PLGA-NPs were evaluated using dynamic light scattering(DLS)and scanning electron microscopy(SEM).Both the encapsulation efficiency and release profile of the herbicide from the PLGA-NPs were typically evaluated by using 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine(atrazine,ATZ)as the model.ATZ encapsulation efficiency within the PLGA-NPs was ranged from 31.6 to 50.5%.The release profiles of ATZ-loaded PLGA-NPs exhibited a much slower release rate in comparison with that of pure herbicide.The results demonstrated that the prepared PLGA-NPs had a high encapsulation efficiency and slow release rate,which could be used as a promising herbicide release system in agriculture to diminish the impact on the environment and minimize the potential harm to the farmers.展开更多
Aspergillus flavus causes serious disease on important agriculture crops, and its secondary metabolic products-aflatoxins are most potent toxin and carcinogen for animal and human, Structural and functional studies of...Aspergillus flavus causes serious disease on important agriculture crops, and its secondary metabolic products-aflatoxins are most potent toxin and carcinogen for animal and human, Structural and functional studies ofA. flavus proteins may provide insights into the identification of potential therapeutic targets and prevention of damage caused by A. flavus. Here, we report the expression, purification, crystallization and preliminary crystallographic analysis of NDK protein from A. flavus. The NDK protein was expressed in E. coli and purified by using a series of chromatographic methods to 〉98% purity. The recombinant protein was crystallized and the crystals diffracted to 2.4 A^° resolution. The crystal of NDK is in space group of C121 with a = 190.84, b = 169.47, c = 146.94 A^°. Preliminary data analysis indicated that the NDK molecule assembles into a multimer in the asymmetric unit.展开更多
Multiform single chain variable fragments (scFvs) including different length linker scFvs and bispecific scFv were constructed. The linker lengths of 0, 3, 5, 8, 12, and 15 amino acids between VH and VL of antideoxy...Multiform single chain variable fragments (scFvs) including different length linker scFvs and bispecific scFv were constructed. The linker lengths of 0, 3, 5, 8, 12, and 15 amino acids between VH and VL of antideoxynivalenol (anti-DON) scFv were used to analyze the affinities of scFvs. The affinity constants of these scFvs increased when the linker was lower than 12 amino acids. The affinity constant would not change when the linker was longer than 12 amino acids. Fusion gene of anti-DON scFv and antizearalenone (anti-ZEN) scFv was also constructed through connection by a short peptide linker DNA to express a bispecific scFv. The affinity constants assay showed that the two scFvs of fusion bispecific scFv remained their own affinity compared to their parental scFvs. Competitive direct enzyme linked immunosorbent assay was used to detect DON and ZEN in contaminated wheat (Triticum aestivum L.) samples, and the results indicated that this bispecific scFv was applicable in DON and ZEN detection. This work confirmed that bispecific scFv could be successfully obtained, and might also have an application in diagnosing fungal infection, and breeding transgenic plants.展开更多
Field-collected Culicoides oxystoma adults were exposed to different concentrations of commercial insecticides including chlorpyrifos, DDVP, deltamethyrin, beta-cypermethrin and beta--cypermethrin · emamectin ben...Field-collected Culicoides oxystoma adults were exposed to different concentrations of commercial insecticides including chlorpyrifos, DDVP, deltamethyrin, beta-cypermethrin and beta--cypermethrin · emamectin benzoate via filter paper method, to determine toxicity of different insecticides on C. oxystoma. Results showed that toxicities varied significantly among insecticides. Biting midges were the most susceptible to deltamethyrin (0. 060 mg/L), followed by chlorpyrifos (0. 588 mg/L), beta-cypermethrin ( 1. 741 rag/L), beta-cypermethrin · emamectin benzoate (99.670 mg/L), and DDVP (600. 496 mg/L). After exposed to insecticides for 1 h, tested midges were transferred to recovery chamber and observed for another 24 h ; increased mortality within this period was different under different concentrations of each insecticide. Relative toxicity index of dehamethrin was maximal when used as the standard reagent.展开更多
In this paper, we developed a rapid and accurate method for the detection of Vibrio parahaemolyticus strains, using multiplex PCR and DNA--DNA hybridization. Multiplex PCR was used to simultaneously amplify three diag...In this paper, we developed a rapid and accurate method for the detection of Vibrio parahaemolyticus strains, using multiplex PCR and DNA--DNA hybridization. Multiplex PCR was used to simultaneously amplify three diagnostic genes (tlh, tdh andfla) that serve as molecular markers of V. parahaemolyticus. Biotinylated PCR products were hybridized to primers immobilized on a microarray, and detected by chemiluminesce with avidin-conjugated alkaline phosphatase. With this method, forty-five samples were tested. Eight known virulent strains (tlh+/tdh+/fla+) and four known avirulent strains (tlh+/tdh /fla+) of the V. parahaemolyticus were successfully detected, and no non-specific hybridization and cross-hybridization reaction were found from fifteen closely-related strains (tlh-/tdh-/fla+) of the Vibrio spp. In addition, all the other eighteen strains of non-Vibrio bacteria (tlh-/tdh /fla-) gave negative results. The DNA microarray successfully distinguished V. parahaemolyticus from other Vibrio spp. The results demonstrated that this was an efficient and robust method for identifying virulent strains of V. parahaemolyticus.展开更多
Crop allelopathy is a promising and environmentally friendly method in weed control;however,the inducible genetic trait for allelopathy in the suppression of weeds needs to be overcome for practical use.Further study ...Crop allelopathy is a promising and environmentally friendly method in weed control;however,the inducible genetic trait for allelopathy in the suppression of weeds needs to be overcome for practical use.Further study needs to be directed to this end to elucidate the molecular genetics and its physiologic mechanism.In this paper,the authors review recent advances in the investigation of rice allelopathy and its molecular regulatory mechanism,especially in responses to stressful conditions including biotic and abiotic factors in China.Previous studies show that rice allelopathy could be enhanced when the rice accession was exposed to stressful conditions,and further analysis by the transcriptomics and proteomics approaches conducted in our laboratory indicated that the increase in allelopathic potential of rice,when exposed to the stresses,was attributed to increased expression level of genes involved in phenolic synthetic metabolism.The increasing phenolic compounds have been confirmed as the main allelochemicals and they jointly act to suppress the target,especially in responses to stressful condition,but it seems to be the primary effect in phenolic allelopathy.We still wonder how the exudates from rice root,which were released into rhizosphere soil,are transformed by soil microorganism to produce the higher secondary effect of phenolic allelopathy in the suppression of weeds.Therefore,the authors suggest that rhizosphere biologic properties of allelopathy in rice and its mechanism are being the key research areas in the world now,and systems biology and its approaches,such as metagenomics and metaproteomics,would be helpful to reveal the process and its molecular ecological mechanism regarding rhizospheric biology of rice allelopathy.展开更多
The novel full length of cytochrome P450 gene has been isolated in insecticideresistant (named CYP6CXlvl) and -susceptible (named CYP6CXlv2) Bemisia tabaci, which was identified as B biotype, in Shangjie, Fujian, ...The novel full length of cytochrome P450 gene has been isolated in insecticideresistant (named CYP6CXlvl) and -susceptible (named CYP6CXlv2) Bemisia tabaci, which was identified as B biotype, in Shangjie, Fujian, China (Sj). CYP6CX1 (1 940 bp contained a 1 557 bp open reading frame) included conserved domains common to CYP6 members, such as heme-binding motif PFGEGPRFCIA, putative "meander"-binding sequence ETLR and PERF in helix-K, oxygen-binding motif AGLDPV and conserved sequence PEKFNP near the carboxyl end. There were four different replacements of amino acid residues between R and S B. tabaci (Thr300 Ala, Thr354Pro, Arg486His and Ile503Thr), among which the substitution Ile503Thr was located in the substrate recognition sites region. The mRNA transcription level of CYP6CXlvl was 2.38-fold as high as that of CYP6CXlv2. The results indicated that the CFP6CX1 from the B biotype B. tabaci in Sj was one of the CYP6 members, and enhanced CYP6CX1 expression and substitute of amino acid residues might be involved in the resistance mechanisms in field B. tabaci.展开更多
Temporal and spatial correlated variations on the methamidophos resistance and biomolecular rate constant of acetylcholinesterase to insecticides were found between the turnip aphid, Lipaphis erysimi and its endoparas...Temporal and spatial correlated variations on the methamidophos resistance and biomolecular rate constant of acetylcholinesterase to insecticides were found between the turnip aphid, Lipaphis erysimi and its endoparasitoid, Diaeretilla rapae, collected from field colonies and an insecticide-free field insectarium in Fujian, China. Compared to the related susceptible insectarium population, L. erysimi and D. rapae displayed 7.4-29.2- and 2.6- 9.2-fold resistance ratios, respectively. In addition, two populations ofL. erysimi with different methamidophos resistance levels, that is, a field (with 5.8-fold resistance ratio) and an insectarium population, were used to study the effects of methamidophos ingested by the host insect on D. rapae development. The percentage of D. rapae cocoon formation decreased significantly when the parasitized L. erysimi were fed on cauliflower leaves treated with methamidophos at lethal concentration dosages 10 (LC50) or LC520. At LC50 dosages the percentage of D. rapae cocoon formation and adult emergence decreased significantly. When the parasitized L. erysimi were fed on methamidophos at LC50 dosage, no D. rapae cocoons were found. When the field or insectarium L. erysimi were treated with methamidophos at LC50, the susceptibility to methamidophos in the adult D. rapae emerged from the treated host insect was similar to the control. However, the susceptibility to methamidophos in the adult D. rapae became lower than the control when the host insects were treated at LC50 dosages. The data thus suggested that the methamidophos ingested by the host insect L. erysimi could be an important factor in the endoparasitoids' insecticide resistance development. The natural selectivity would favor the parasitoids that had developed an insensitivity to the insecticide(s).展开更多
Chromium(Cr) may cause losses in the yield of field plant, which is one of the favorite habitats of Bacillus thuringiensis(Bt). The purposes of our study were to assess the Cr(VI)-resistance and Cr(VI)-reducing abilit...Chromium(Cr) may cause losses in the yield of field plant, which is one of the favorite habitats of Bacillus thuringiensis(Bt). The purposes of our study were to assess the Cr(VI)-resistance and Cr(VI)-reducing abilities of an indigenous soil isolate of Bt and to determine the factors governing Cr(VI) reduction. Towards this end a novel dichromate-reducing Bt BRC-ZYR2, characterized with insecticidal crystal proteins(ICPs), was isolated from a uranium deposit. Minimum inhibitory concentrations(MICs) of Cr(VI) were determined by broth dilution method and the concentrations of Cr(VI) and total Cr in the supernatant were quantified colorimetrically using 1,5-diphenylcarbazide(DPC) reagent and a mixture of sulfuric-nitric acids, respectively. The isolate contained five ICP genes(cry1Ba, cry1 Bb, cry1Be/cry1 Bf, cry9 Ca and cry9Da) and exhibited a high level of Cr(VI) resistance with MICs of 150 mg L-1at pH 7.0 and 30?C, and 500 mg L-1under optimal conditions(pH 9.0 and 40?C). The total Cr concentration was similar to initial concentration of Cr(VI) under the optimal condition, suggesting that the essential removal of the Cr(VI) was dependent on Bt reduction. Under optimal conditions, the initial Cr(VI) concentrations from 25 to 75 mg L-1significantly decreased in 24 h after incubation. Addition of Mn2+, Co2+, Mo2+and Cu2+activated Bt-mediated Cr(VI) reduction, while Zn2+, Ni2+and glucose were found to inhibit the reduction. Our results indicated that this isolate could be a promising biopesticide with the potential for both insect biocontrol and Cr bioremediation in the field.展开更多
基金supported by grants from the National Natural Science Foundation of China (81303170, 2012CB126309 and U1205021)the Chinese Postdoctoral Science Foundation (2013M541849)
文摘Maize/peanut intercropping system shows the significant yield advantage. Soil microbes play major roles in soil nutrient cycling and were affected by intercropping plants. This experiment was carried out to evaluate the changing of rhizosphere microbial community composition, and the relationship between microbial community and soil enzymatic activities, soil nutrients in maize/peanut intercropping system under the following three treatments: maize (Zea mays L.) and peanut (Arachis hypogaea L.) were intercropped without any separation (NS), by half separation (HS) using a nylon net (50 μm) and complete separation (CS) by using a plastic sheet, respectively. The soil microbial communities were assessed by phospholipid fatty acid (PLFA). We found that soil available nutrients (available nitrogen (Avail N) and available phosphorus (Avail P)) and enzymatic activities (soil urase and phosphomonoesterase) in both crops were improved in NS and HS treatments as compared to CS. Both bacterial and fungal biomasses in both crops were increased in NS followed by HS. Furthermore, Gram-positive bacteria (G+) in maize soils were significant higher in NS and HS than CS, while the Gram-negative (G-) was significant higher in peanut soil. The ratio of normal saturated to monounsaturated PLFAs was significantly higher in rhizosphere of peanut under CS treatment than in any other treatments, which is an indicator of nutrient stress. Redundancy analysis and cluster analysis of PLFA showed rhizospheric microbial community of NS and HS of both plants tended to be consistent. The urase and Avail N were higher in NS and HS of both plants and positively correlated with bacteria, fungi (F) and total PLFAs, while negatively correlated with G+/G- and NS/MS. The findings suggest that belowground interactions in maize/peanut intercropping system play important roles in changing the soil microbial composition and the dominant microbial species, which was closely related with the improving of soil available nutrients (N and P) and enzymatic activities.
基金financially supported by the Third Xinjiang Comprehensive Scientific Expedition (2022xjkk020605)the Xinjiang Uygur Autonomous Region Regional Coordinated Innovation Project (Shanghai Cooperation Organization Science and Technology Partnership Program) (2020E01047)supported by the Introduction Project of High-level Talents in Xinjiang Uygur Autonomous Region, China
文摘Endophytes,as crucial components of plant microbial communities,significantly contribute to enhancing the absorption of nutrients such as nitrogen and phosphorus by their hosts,promote plant growth,and degrade pathogenic fungal mycelia.In this study,an experiment was conducted in August 2022 to explore the growth-promoting potential of endophytic bacterial strains isolated from two medical plant species,Thymus altaicus and Salvia deserta,using a series of screening media.Plant samples of Thymus altaicus and Salvia deserta were collected from Zhaosu County and Habahe County in Xinjiang Uygur Autonomous Region,China,in July 2021.Additionally,the inhibitory effects of endophytic bacterial strains on the four pathogenic fungi(Fusarium oxysporum,Fulvia fulva,Alternaria solani,and Valsa mali)were determined through the plate confrontation method.A total of 80 endophytic bacterial strains were isolated from Thymus altaicus,while a total of 60 endophytic bacterial strains were isolated from Salvia deserta.The endophytic bacterial strains from both Thymus altaicus and Salvia deserta exhibited plant growth-promoting properties.Specifically,the strains of Bacillus sp.TR002,Bacillus sp.TR005,Microbacterium sp.TSB5,and Rhodococcus sp.TR013 demonstrated strong cellulase-producing activity,siderophore-producing activity,phosphate solubilization activity,and nitrogen-fixing activity,respectively.Out of 140 endophytic bacterial strains isolated from Thymus altaicus and Salvia deserta,104 strains displayed anti-fungal activity against Fulvia fulva,Alternaria solani,Fusarium oxysporum,and Valsa mali.Furthermore,the strains of Bacillus sp.TR005,Bacillus sp.TS003,and Bacillus sp.TSB7 exhibited robust inhibition rates against all the four pathogenic fungi.In conclusion,the endophytic bacterial strains from Thymus altaicus and Salvia deserta possess both plant growth-promoting and anti-fungal properties,making them promising candidates for future development as growth-promoting agents and biocontrol tools for plant diseases.
基金the National Natural Science Foundation of China (No. 30471178)the Ministry of Agriculture of China (No.nyhyzx07-054)
文摘A new stem rot disease is found to occur naturally on Arabidopsis plants in greenhouses of Fuzhou, China. In order to identify its pathogen, we conducted a series of fungal isolation and purification, plant reinoculation, and ascus and ascospore induction from the sclerotia. The isolate caused typical water-soaked lesions after reinoculation and produced sclerotia both on Arabidopsis plants and culture medium plates, and the sclerotia could be induced to produce discal apothecia and 8 binucleate ascospores per ascus. These disease symptom and fungal morphology data revealed that the fungus Sclerotinia sclerotiorum (Lib.) de Bary was the pathogen for Arabidopsis stem rot. To confirm this, we further amplified its large subunit ribosomal DNA (LSU rDNA) by polymerase chain reaction (PCR), and compared the sequence with the known LSU rDNA sequences in GenBank. The results show that the sequence shares the highest identities with the LSU rDNAs of different S. sclerotiorum strains. Taking all these data together, we concluded that the fungus that caused the Arabidopsis stem rot is S. sclerotiorum (Lib.) de Bary. This is the first report that Arabidopsis is naturally infected by S. sclerotiorum.
基金financial supports of the National Natural Science Foundation of China(30671347)the Commonweal Specialized Research Fund of China Agriculture(201103016)the Fujian Provincial Science Foundation,China(2012J01079)
文摘Atrazine is the second mostly used herbicide in USA,but low utilization ratio causes severe environmental problem,so controlled release system is highly needed in order to minimize the negative impact on environment.In this paper,a herbicide delivery system,atrazine-loaded poly(lactic-co-glycolic acid)(PLGA)nanoparticles(NPs)were prepared by forming an oilin-water emulsion using the emulsion-solvent evaporation method.By varying the preparation conditions of PLGA-NPs,such as sonication time,surfactant content,solvent fraction,and polymer content,the particle sizes of the PLGA-NPs were well controlled from 204 to 520 nm.The morphology and size distribution of PLGA-NPs were evaluated using dynamic light scattering(DLS)and scanning electron microscopy(SEM).Both the encapsulation efficiency and release profile of the herbicide from the PLGA-NPs were typically evaluated by using 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine(atrazine,ATZ)as the model.ATZ encapsulation efficiency within the PLGA-NPs was ranged from 31.6 to 50.5%.The release profiles of ATZ-loaded PLGA-NPs exhibited a much slower release rate in comparison with that of pure herbicide.The results demonstrated that the prepared PLGA-NPs had a high encapsulation efficiency and slow release rate,which could be used as a promising herbicide release system in agriculture to diminish the impact on the environment and minimize the potential harm to the farmers.
基金supported by National 973 Program(No.2013CB127802)of Ministry of Science and Technology of Chinathe National Natural Science Foundation of China(Nos.31172297 and 31400100)
文摘Aspergillus flavus causes serious disease on important agriculture crops, and its secondary metabolic products-aflatoxins are most potent toxin and carcinogen for animal and human, Structural and functional studies ofA. flavus proteins may provide insights into the identification of potential therapeutic targets and prevention of damage caused by A. flavus. Here, we report the expression, purification, crystallization and preliminary crystallographic analysis of NDK protein from A. flavus. The NDK protein was expressed in E. coli and purified by using a series of chromatographic methods to 〉98% purity. The recombinant protein was crystallized and the crystals diffracted to 2.4 A^° resolution. The crystal of NDK is in space group of C121 with a = 190.84, b = 169.47, c = 146.94 A^°. Preliminary data analysis indicated that the NDK molecule assembles into a multimer in the asymmetric unit.
基金the National High Technology Research and Development Program of China (No. 2007AA10Z430) Chinese National Natural Science Foundation (No. 30771400 and 30500325)+2 种基金Key Scientific and Technology Project of Fujian Province of China (No. 2005K030 , 2007Y0002) Postdoctoral Sciences Foundation of China (No. 20060390183) Program for New Century Excellent Talents in Fujian Province University.
文摘Multiform single chain variable fragments (scFvs) including different length linker scFvs and bispecific scFv were constructed. The linker lengths of 0, 3, 5, 8, 12, and 15 amino acids between VH and VL of antideoxynivalenol (anti-DON) scFv were used to analyze the affinities of scFvs. The affinity constants of these scFvs increased when the linker was lower than 12 amino acids. The affinity constant would not change when the linker was longer than 12 amino acids. Fusion gene of anti-DON scFv and antizearalenone (anti-ZEN) scFv was also constructed through connection by a short peptide linker DNA to express a bispecific scFv. The affinity constants assay showed that the two scFvs of fusion bispecific scFv remained their own affinity compared to their parental scFvs. Competitive direct enzyme linked immunosorbent assay was used to detect DON and ZEN in contaminated wheat (Triticum aestivum L.) samples, and the results indicated that this bispecific scFv was applicable in DON and ZEN detection. This work confirmed that bispecific scFv could be successfully obtained, and might also have an application in diagnosing fungal infection, and breeding transgenic plants.
基金Supported by Key Science and Technology Project of Fujian Province(2014I0001)Science and Technology Plan of General Administration of Quality Supervision,Inspection and Quarantine of China(AQSIQ)(2015IK036)
文摘Field-collected Culicoides oxystoma adults were exposed to different concentrations of commercial insecticides including chlorpyrifos, DDVP, deltamethyrin, beta-cypermethrin and beta--cypermethrin · emamectin benzoate via filter paper method, to determine toxicity of different insecticides on C. oxystoma. Results showed that toxicities varied significantly among insecticides. Biting midges were the most susceptible to deltamethyrin (0. 060 mg/L), followed by chlorpyrifos (0. 588 mg/L), beta-cypermethrin ( 1. 741 rag/L), beta-cypermethrin · emamectin benzoate (99.670 mg/L), and DDVP (600. 496 mg/L). After exposed to insecticides for 1 h, tested midges were transferred to recovery chamber and observed for another 24 h ; increased mortality within this period was different under different concentrations of each insecticide. Relative toxicity index of dehamethrin was maximal when used as the standard reagent.
基金financial supports from National High Technology Research and Development Program of China(No.2007AA10Z430)National Natural Science Foundation of China(No.30700535)Program for New Century Excellent Talents in Fujian Province University,and Fok Ying Tong Education Foundation(No.111032)
文摘In this paper, we developed a rapid and accurate method for the detection of Vibrio parahaemolyticus strains, using multiplex PCR and DNA--DNA hybridization. Multiplex PCR was used to simultaneously amplify three diagnostic genes (tlh, tdh andfla) that serve as molecular markers of V. parahaemolyticus. Biotinylated PCR products were hybridized to primers immobilized on a microarray, and detected by chemiluminesce with avidin-conjugated alkaline phosphatase. With this method, forty-five samples were tested. Eight known virulent strains (tlh+/tdh+/fla+) and four known avirulent strains (tlh+/tdh /fla+) of the V. parahaemolyticus were successfully detected, and no non-specific hybridization and cross-hybridization reaction were found from fifteen closely-related strains (tlh-/tdh-/fla+) of the Vibrio spp. In addition, all the other eighteen strains of non-Vibrio bacteria (tlh-/tdh /fla-) gave negative results. The DNA microarray successfully distinguished V. parahaemolyticus from other Vibrio spp. The results demonstrated that this was an efficient and robust method for identifying virulent strains of V. parahaemolyticus.
基金This work was supported by The National Natural Science Foundation of China(Grant Nos.30671220,30471028,30200170,and 30070068)Provincial Natural Science Foundation of Fujian,China(Nos.2009J05045,20020F012,and K04038).
文摘Crop allelopathy is a promising and environmentally friendly method in weed control;however,the inducible genetic trait for allelopathy in the suppression of weeds needs to be overcome for practical use.Further study needs to be directed to this end to elucidate the molecular genetics and its physiologic mechanism.In this paper,the authors review recent advances in the investigation of rice allelopathy and its molecular regulatory mechanism,especially in responses to stressful conditions including biotic and abiotic factors in China.Previous studies show that rice allelopathy could be enhanced when the rice accession was exposed to stressful conditions,and further analysis by the transcriptomics and proteomics approaches conducted in our laboratory indicated that the increase in allelopathic potential of rice,when exposed to the stresses,was attributed to increased expression level of genes involved in phenolic synthetic metabolism.The increasing phenolic compounds have been confirmed as the main allelochemicals and they jointly act to suppress the target,especially in responses to stressful condition,but it seems to be the primary effect in phenolic allelopathy.We still wonder how the exudates from rice root,which were released into rhizosphere soil,are transformed by soil microorganism to produce the higher secondary effect of phenolic allelopathy in the suppression of weeds.Therefore,the authors suggest that rhizosphere biologic properties of allelopathy in rice and its mechanism are being the key research areas in the world now,and systems biology and its approaches,such as metagenomics and metaproteomics,would be helpful to reveal the process and its molecular ecological mechanism regarding rhizospheric biology of rice allelopathy.
文摘The novel full length of cytochrome P450 gene has been isolated in insecticideresistant (named CYP6CXlvl) and -susceptible (named CYP6CXlv2) Bemisia tabaci, which was identified as B biotype, in Shangjie, Fujian, China (Sj). CYP6CX1 (1 940 bp contained a 1 557 bp open reading frame) included conserved domains common to CYP6 members, such as heme-binding motif PFGEGPRFCIA, putative "meander"-binding sequence ETLR and PERF in helix-K, oxygen-binding motif AGLDPV and conserved sequence PEKFNP near the carboxyl end. There were four different replacements of amino acid residues between R and S B. tabaci (Thr300 Ala, Thr354Pro, Arg486His and Ile503Thr), among which the substitution Ile503Thr was located in the substrate recognition sites region. The mRNA transcription level of CYP6CXlvl was 2.38-fold as high as that of CYP6CXlv2. The results indicated that the CFP6CX1 from the B biotype B. tabaci in Sj was one of the CYP6 members, and enhanced CYP6CX1 expression and substitute of amino acid residues might be involved in the resistance mechanisms in field B. tabaci.
文摘Temporal and spatial correlated variations on the methamidophos resistance and biomolecular rate constant of acetylcholinesterase to insecticides were found between the turnip aphid, Lipaphis erysimi and its endoparasitoid, Diaeretilla rapae, collected from field colonies and an insecticide-free field insectarium in Fujian, China. Compared to the related susceptible insectarium population, L. erysimi and D. rapae displayed 7.4-29.2- and 2.6- 9.2-fold resistance ratios, respectively. In addition, two populations ofL. erysimi with different methamidophos resistance levels, that is, a field (with 5.8-fold resistance ratio) and an insectarium population, were used to study the effects of methamidophos ingested by the host insect on D. rapae development. The percentage of D. rapae cocoon formation decreased significantly when the parasitized L. erysimi were fed on cauliflower leaves treated with methamidophos at lethal concentration dosages 10 (LC50) or LC520. At LC50 dosages the percentage of D. rapae cocoon formation and adult emergence decreased significantly. When the parasitized L. erysimi were fed on methamidophos at LC50 dosage, no D. rapae cocoons were found. When the field or insectarium L. erysimi were treated with methamidophos at LC50, the susceptibility to methamidophos in the adult D. rapae emerged from the treated host insect was similar to the control. However, the susceptibility to methamidophos in the adult D. rapae became lower than the control when the host insects were treated at LC50 dosages. The data thus suggested that the methamidophos ingested by the host insect L. erysimi could be an important factor in the endoparasitoids' insecticide resistance development. The natural selectivity would favor the parasitoids that had developed an insensitivity to the insecticide(s).
基金Acknowledgments This work was supported by the Natural Science Foundation of Fujian, China (No. B0410016) and China-Japan Cooperation Program by Science and Technique Bureau of Fujian Province, China (20051002). This work was also supported in part by Grants-in-Aid from the Japan Society for the Promotion of Science (Nos. (A) 11356002 and (C) 14606001) and China-Japan Cooperated Program by JSPS.
基金Supported by the National Science and Technology Project in Rural Area during the"2th Five-Year Plan",China(Nos.2011AA10A203 and 2011BAD03B02-2)the National Natural Science Foundation of China(No.31201574)+3 种基金the Project of Fujian Provincial Department of Science and Technology,China(No.2011N5003)the State Key Laboratory for Biology of Plant Diseases and Insect Pests,Institute of Plant Protection,Chinese Academy of Agricultural Sciences(No.SKL2012OP05)the Talent Training Program for Distinguished Young Scholars in Universities of Fujian Province,China(No.JA12092)the Science Fund for Distinguished Young Scholars of Fujian Agriculture and Forestry University,China(No.xjq201203)
文摘Chromium(Cr) may cause losses in the yield of field plant, which is one of the favorite habitats of Bacillus thuringiensis(Bt). The purposes of our study were to assess the Cr(VI)-resistance and Cr(VI)-reducing abilities of an indigenous soil isolate of Bt and to determine the factors governing Cr(VI) reduction. Towards this end a novel dichromate-reducing Bt BRC-ZYR2, characterized with insecticidal crystal proteins(ICPs), was isolated from a uranium deposit. Minimum inhibitory concentrations(MICs) of Cr(VI) were determined by broth dilution method and the concentrations of Cr(VI) and total Cr in the supernatant were quantified colorimetrically using 1,5-diphenylcarbazide(DPC) reagent and a mixture of sulfuric-nitric acids, respectively. The isolate contained five ICP genes(cry1Ba, cry1 Bb, cry1Be/cry1 Bf, cry9 Ca and cry9Da) and exhibited a high level of Cr(VI) resistance with MICs of 150 mg L-1at pH 7.0 and 30?C, and 500 mg L-1under optimal conditions(pH 9.0 and 40?C). The total Cr concentration was similar to initial concentration of Cr(VI) under the optimal condition, suggesting that the essential removal of the Cr(VI) was dependent on Bt reduction. Under optimal conditions, the initial Cr(VI) concentrations from 25 to 75 mg L-1significantly decreased in 24 h after incubation. Addition of Mn2+, Co2+, Mo2+and Cu2+activated Bt-mediated Cr(VI) reduction, while Zn2+, Ni2+and glucose were found to inhibit the reduction. Our results indicated that this isolate could be a promising biopesticide with the potential for both insect biocontrol and Cr bioremediation in the field.