The fall armyworm(FAW),Spodoptera frugiperda Smith(Lepidoptera:Noctuidae)is an important agricultural pest that invaded China in the middle of December 2018.As a polyphagous pest,FAW is identified as a serious threat ...The fall armyworm(FAW),Spodoptera frugiperda Smith(Lepidoptera:Noctuidae)is an important agricultural pest that invaded China in the middle of December 2018.As a polyphagous pest,FAW is identified as a serious threat to agricultural production and food security in China.Pepper(Capsicum annuum L.),tomato(Solanum lycopersicum Mill.)and eggplant(Solanum melongena L.)are three of dominant solanaceous vegetables of this country.To our knowledge,the effects of these plants on the performances of FAW have not been well studied.In this study we assessed the fitness of this pest to these three plants.Results showed that FAW can complete its life cycle when fed with tomato and pepper,but not on eggplant.The population parameters of FAW fed with maize(Zea mays L.)and the three solanaceous vegetables were compared using the age-stage,two-sex life table method.Developmental duration was significantly different in the larval stage,but not in the pupae stage.FAW fed with pepper had the longest pre-adult period(41.73 d)and the lightest pupal weight(0.1134 g);the survival rate was lower than FAW fed with tomato.Significant differences were observed in the mean fecundity of female,with the highest(943.95 eggs)laid by FAW fed with tomato.FAW had the shortest mean generation time(T),the highest intrinsic rate of increase(r)and finite rate of increase(λ)on maize,and the highest net reproductive rate(R_(0))on tomato.Overall,FAW fitness on the three solanaceous vegetables was:tomato>pepper>eggplant.This study provides the foundation for further assessment of FAW risk to solanaceous vegetables and for establishing corresponding control strategies in China.展开更多
Three different regeneration processes including hydrogen or nitrogen purging and coke-burning treatment were used to restore the Pt-Sn/γ-AlOcatalysts, through which propane dehydrogenation reaction was performed in ...Three different regeneration processes including hydrogen or nitrogen purging and coke-burning treatment were used to restore the Pt-Sn/γ-AlOcatalysts, through which propane dehydrogenation reaction was performed in a consecutive reaction-regeneration mode. It was found that the catalyst using hydrogen regeneration showed the best stability compared with those regenerated by nitrogen purging and coke-burning treatment, suggesting that hydrogen regeneration is an effective approach for maintaining the performance of Pt-Sn/γ-AlOcatalysts in propane dehydrogenation reaction. The effect of different regeneration atmospheres on the metal active center and the coke deposition was investigated by XRD,TEM, N-physisorption, TPO, TG and Raman technologies, and the results revealed that hydrogen or nitrogen regeneration resulted in little impact on the size and structure of metal active center, retaining the effective Pt Sn phase over the catalyst. Moreover, hydrogen regeneration not only removed the low dense components of the coke, but also altered the property of the residual coke through hydrogenation, leading to a higher mobility of coke, and thus a higher accessibility of the metal active centers. Whereas nitrogen regeneration only removed the low dense components of the coke. Although coke-burning regeneration caused a thorough coke removal, the catalyst subjected to repeated redox exhibited poor stability due to metal agglomeration, phase segregation and the resulting large PtSn particle and core-shell structure with a Sn-rich surface.展开更多
The composite catalytic materials based on the mineral kaolinite are considered to be a potential approach for solving global energy scarcity and environmental pollution,which have excellent catalytic performance,low ...The composite catalytic materials based on the mineral kaolinite are considered to be a potential approach for solving global energy scarcity and environmental pollution,which have excellent catalytic performance,low cost and excellent chemical stability.However,pure kaolinite does not have visible light absorption ability and cannot be used as a potential photocatalytic material.Fortunately,the unique physical and chemical properties of kaolinite can be acted as a good semiconductor carrier.Herein,this paper firstly presents the mineralogical characteristics of kaolinite.Next,kaolinite-based photocatalysts(such as TiO_(2)/kaolinite,g-C_(3)N_(4)/kaolinite,g-C_(3)N_(4)/TiO_(2)/kaolinite,Zn O)are discussed in detail from the formation of heterostructures,synthesis-modification methods,photocatalytic mechanisms,and electron transfer pathways.Furthermore,the specific role of kaolinite in photocatalytic materials is summarized and discussed.In addition,the photocatalytic applications of kaolinite-based photocatalysts in the fields of water decomposition,pollutant degradation,bacterial disinfection are reviewed.However,the modification of kaolinite is hard,the manufacture of a large number of kaolinite-based photocatalysts is difficult,the cost of doping noble metals is expensive,and the utilization rate of visible light is low,which limits its application in industrial practice.Finally,this paper presents some perspectives on the future development of kaolinite-based photocatalysts.展开更多
Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial production.Here,we developed a mobile C...Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial production.Here,we developed a mobile CRISPR-Cas9 based anti-phage system for bacteriophages defense in E.coli.Two conjugative plasmids pGM1(phosphoglucomutase 1)and pGM2 carrying one and two guide RNAs,respectively,were designed to defend against a filamentous phage.The results showed that the pGM1 and pGM2 could decrease the phage infection rate to 1.6%and 0.2%respectively in infected cells.For preventing phage infection in E.coli,the pGM2 decreased the phage infection rate to 0.1%,while pGM1 failed to block phage infection.Sequence verification revealed that point mutations in protospacer or protospacer adjacent motif sequences of the phage genome caused loss of the defense function.These results support the potential application of MCBAS in E.coli cell factories to defend against phage infections.展开更多
基金supported by the Science and Technology Program of Guizhou Province,China([2019]2412)the Basic Research Program(Science and Technology)of Guizhou Province,China([2020]1Z021)。
文摘The fall armyworm(FAW),Spodoptera frugiperda Smith(Lepidoptera:Noctuidae)is an important agricultural pest that invaded China in the middle of December 2018.As a polyphagous pest,FAW is identified as a serious threat to agricultural production and food security in China.Pepper(Capsicum annuum L.),tomato(Solanum lycopersicum Mill.)and eggplant(Solanum melongena L.)are three of dominant solanaceous vegetables of this country.To our knowledge,the effects of these plants on the performances of FAW have not been well studied.In this study we assessed the fitness of this pest to these three plants.Results showed that FAW can complete its life cycle when fed with tomato and pepper,but not on eggplant.The population parameters of FAW fed with maize(Zea mays L.)and the three solanaceous vegetables were compared using the age-stage,two-sex life table method.Developmental duration was significantly different in the larval stage,but not in the pupae stage.FAW fed with pepper had the longest pre-adult period(41.73 d)and the lightest pupal weight(0.1134 g);the survival rate was lower than FAW fed with tomato.Significant differences were observed in the mean fecundity of female,with the highest(943.95 eggs)laid by FAW fed with tomato.FAW had the shortest mean generation time(T),the highest intrinsic rate of increase(r)and finite rate of increase(λ)on maize,and the highest net reproductive rate(R_(0))on tomato.Overall,FAW fitness on the three solanaceous vegetables was:tomato>pepper>eggplant.This study provides the foundation for further assessment of FAW risk to solanaceous vegetables and for establishing corresponding control strategies in China.
基金supported by the National Natural Science Foundation of China(nos.21103182,21273049)the Natural Science Foundation of Guangdong Province(no.S2013050014127)Education Department Funding of Guangdong Province(nos.CGZHZD1104,2013CXZDA016).
文摘Three different regeneration processes including hydrogen or nitrogen purging and coke-burning treatment were used to restore the Pt-Sn/γ-AlOcatalysts, through which propane dehydrogenation reaction was performed in a consecutive reaction-regeneration mode. It was found that the catalyst using hydrogen regeneration showed the best stability compared with those regenerated by nitrogen purging and coke-burning treatment, suggesting that hydrogen regeneration is an effective approach for maintaining the performance of Pt-Sn/γ-AlOcatalysts in propane dehydrogenation reaction. The effect of different regeneration atmospheres on the metal active center and the coke deposition was investigated by XRD,TEM, N-physisorption, TPO, TG and Raman technologies, and the results revealed that hydrogen or nitrogen regeneration resulted in little impact on the size and structure of metal active center, retaining the effective Pt Sn phase over the catalyst. Moreover, hydrogen regeneration not only removed the low dense components of the coke, but also altered the property of the residual coke through hydrogenation, leading to a higher mobility of coke, and thus a higher accessibility of the metal active centers. Whereas nitrogen regeneration only removed the low dense components of the coke. Although coke-burning regeneration caused a thorough coke removal, the catalyst subjected to repeated redox exhibited poor stability due to metal agglomeration, phase segregation and the resulting large PtSn particle and core-shell structure with a Sn-rich surface.
基金the financial support provided by the Science and Technology Major Projects of Shanxi Province of China(No.20181101003)Special Funds for Basic Scientific Research of Central Colleges(No.300102299306,300102299304)。
文摘The composite catalytic materials based on the mineral kaolinite are considered to be a potential approach for solving global energy scarcity and environmental pollution,which have excellent catalytic performance,low cost and excellent chemical stability.However,pure kaolinite does not have visible light absorption ability and cannot be used as a potential photocatalytic material.Fortunately,the unique physical and chemical properties of kaolinite can be acted as a good semiconductor carrier.Herein,this paper firstly presents the mineralogical characteristics of kaolinite.Next,kaolinite-based photocatalysts(such as TiO_(2)/kaolinite,g-C_(3)N_(4)/kaolinite,g-C_(3)N_(4)/TiO_(2)/kaolinite,Zn O)are discussed in detail from the formation of heterostructures,synthesis-modification methods,photocatalytic mechanisms,and electron transfer pathways.Furthermore,the specific role of kaolinite in photocatalytic materials is summarized and discussed.In addition,the photocatalytic applications of kaolinite-based photocatalysts in the fields of water decomposition,pollutant degradation,bacterial disinfection are reviewed.However,the modification of kaolinite is hard,the manufacture of a large number of kaolinite-based photocatalysts is difficult,the cost of doping noble metals is expensive,and the utilization rate of visible light is low,which limits its application in industrial practice.Finally,this paper presents some perspectives on the future development of kaolinite-based photocatalysts.
基金support from the National Key Research and Development Program of China(Grant No.2019YFA0903800)the National Natural Science Foundation of China(Grant Nos.31800719,21621004)the International(regional)cooperation and exchange projects(Grant No.31861143017).
文摘Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial production.Here,we developed a mobile CRISPR-Cas9 based anti-phage system for bacteriophages defense in E.coli.Two conjugative plasmids pGM1(phosphoglucomutase 1)and pGM2 carrying one and two guide RNAs,respectively,were designed to defend against a filamentous phage.The results showed that the pGM1 and pGM2 could decrease the phage infection rate to 1.6%and 0.2%respectively in infected cells.For preventing phage infection in E.coli,the pGM2 decreased the phage infection rate to 0.1%,while pGM1 failed to block phage infection.Sequence verification revealed that point mutations in protospacer or protospacer adjacent motif sequences of the phage genome caused loss of the defense function.These results support the potential application of MCBAS in E.coli cell factories to defend against phage infections.
