Lycodon(Boie,1826)is a genus of colubrid snakes widely distributed in south,south-east and east Asia comprising 84 species with 22 reported in China.In this study,we identify a unique Lycodon specimen(voucher No.ANU20...Lycodon(Boie,1826)is a genus of colubrid snakes widely distributed in south,south-east and east Asia comprising 84 species with 22 reported in China.In this study,we identify a unique Lycodon specimen(voucher No.ANU20230057)from Yingjiang County,Yunnan Province,China.A phylogenetic analysis using mitochondrial cytochrome b(Cyt b),showed that this specimen formed a monophyletic clade with high nodal supports(BPP=1.00;BS=100)with a specimen of Lycodon jara,a colubrid species mainly distributed in the northern and northeastern region of south Asia.Morphological comparisons also showed that this specimen belongs to L.jara.This discovery confirms the distribution of L.jara in China and expands the range of this species to the south edge of Gaoligong Mountains,and provides the first detailed morphological description of L.jara from China thus increasing the number of Lycodon species in China to 23.展开更多
The naturally occurring prokaryotic CRISPR-Cas systems provide valuable resources for the development of new genome-editing tools.However,the majority of prokaryotic Cas nucleases exhibit poor editing efficiency in ma...The naturally occurring prokaryotic CRISPR-Cas systems provide valuable resources for the development of new genome-editing tools.However,the majority of prokaryotic Cas nucleases exhibit poor editing efficiency in mammalian cells,which significantly limits their utility.Here,we have developed a method termed Improving Editing Activity by Synergistic Engineering(MIDAS).This method exerts a synergistic effect to improve mammalian genome-editing efficiency of a wide range of CRISPR-Cas systems by enhancing the interactions of Cas nuclease with the protospacer adjacent motif(PAM)and the single-stranded DNA(ssDNA)substrate in the catalytic pocket simultaneously.MIDAS robustly and significantly increased the gene-editing efficiency of Cas12i,Cas12b,and CasX in human cells.Notably,a Cas12i variant,Cas12iMax,exhibited robust activity with a very broad PAM range(NTNN,NNTN,NAAN,and NCAN)and higher efficiency than the current widely used Cas nucleases.A high-fidelity version of Cas12iMax(Cas12iHiFi)has been further engineered to minimize off-target effects.Our work provides an expandable and efficacious method for engineering Cas nucleases for robust mammalian genome editing.展开更多
With growing regional economic integration,transportation systems have become critical to regional development and economic vitality but vulnerable to disasters.However,the regional economic ripple effect of a disaste...With growing regional economic integration,transportation systems have become critical to regional development and economic vitality but vulnerable to disasters.However,the regional economic ripple effect of a disaster is difficult to quantify accurately,especially considering the cumulated influence of traffic disruptions.This study explored integrating transportation system analysis with economic modeling to capture the regional economic ripple effect.A state-of-the-art spatial computable general equilibrium model is leveraged to simulate the operation of the economic system,and the marginal rate of transport cost is introduced to reflect traffic network damage post-disaster.The model is applied to the 50-year return period flood in2020 in Hubei Province,China.The results show the following.First,when traffic disruption costs are considered,the total output loss of non-affected areas is 1.81 times than before,and non-negligible losses reach relatively remote zones of the country,such as the Northwest Comprehensive Economic Zone(36%of total ripple effects).Second,traffic disruptions have a significant hindering effect on regional trade activities,especially in the regional intermediate input—about three times more than before.The industries most sensitive to traffic disruptions were transportation,storage,and postal service(5 times),and processing and assembly manufacturing(4.4 times).Third,the longer the distance,the stronger traffic disruptions'impact on interregional intermediate inputs.Thus,increasing investment in transportation infrastructure significantly contributes to mitigating disaster ripple effects and accelerating the process of industrial recovery in affected areas.展开更多
Dear editor.The remarkably diversified CRISPR-Cas systems in nature have provided unlimited valuable resources to develop genome editing tools that are revolutionizing the fields of biotechnology and medicine.However,...Dear editor.The remarkably diversified CRISPR-Cas systems in nature have provided unlimited valuable resources to develop genome editing tools that are revolutionizing the fields of biotechnology and medicine.However,due to their microbial origin,the activity of most naturally occurring CRISPR-Cas nucleases is relatively poor in mammalian cells(Ran et al.,2015).Thus,improving the mammalian genome editing efficiency becomes the priority for harnessing more CRISPRCas systems for widespread applications.Rational protein engineering serves as a powerful approach to enhance the catalytic activity of enzymes.Whereas,this approach largely relies on proteinic three-dimension(3D)structure information as guide for design.The fact is that of the large numbers of the CRISPR-Cas systems discovered in recent years,only a small number of them with the 3D structures were reported.To bypass this limitation,here,we report an efficient and simple strategy for rational engineering of Cas nucleases without the need of 3D structure information and successfully optimized nucleases from Cas9 and Cas12 families.展开更多
The global spread of viruses can lead to the release of large amounts of disinfectants or antiviral drugs into the water environment.The resulting disinfection byproducts(DBPs)and residual antiviral drugs,acting as ge...The global spread of viruses can lead to the release of large amounts of disinfectants or antiviral drugs into the water environment.The resulting disinfection byproducts(DBPs)and residual antiviral drugs,acting as genotoxic substances or their precursors,may pose risks to aquatic animals and drinking water sources;however,to date,no studies have analyzed the changes in genotoxicity in the Yangtze River before and after the epidemic.In the present study,water and sediment samples from the Yangtze River were collected during different seasons,just before and after the outbreak of COVID-19,and were assessed using the SOS/umu test(with and without liver S9).The results indicated that water samples exhibited more pronounced genotoxicity than did sediments,with direct genotoxicity being the primary factor.Additionally,there were significant regional differences,with notably greater genotoxicity observed in the upper Yangtze River than in the lower reaches before the COVID-19 epidemic.However,this trend was reversed six to ten months later,suggesting the accumulation of DBPs or antiviral drugs after the COVID-19 pandemic.Moreover,the risk quotient indicated that 65%of the water samples posed a high risk for Paramecium caudatum,whereas 71%of the samples posed a medium risk for Danio rerio,thereby representing a potential threat to the ecological security of the Yangtze River.In conclusion,this study,at the basin scale,revealed the impacts of COVID-19 on the Yangtze River,highlighting the need to prevent DBPs and pharmaceutical pollution during similar events in the future.展开更多
基金supported by the Key Research and Development Projects of Science and Technology Program of Xizang Autonomous Region(XZ202301ZY0036G)Doctoral Research Starting Foundation of Anhui Normal University(752017)+1 种基金National Natural Science Foundation of China(3147196832470458)。
文摘Lycodon(Boie,1826)is a genus of colubrid snakes widely distributed in south,south-east and east Asia comprising 84 species with 22 reported in China.In this study,we identify a unique Lycodon specimen(voucher No.ANU20230057)from Yingjiang County,Yunnan Province,China.A phylogenetic analysis using mitochondrial cytochrome b(Cyt b),showed that this specimen formed a monophyletic clade with high nodal supports(BPP=1.00;BS=100)with a specimen of Lycodon jara,a colubrid species mainly distributed in the northern and northeastern region of south Asia.Morphological comparisons also showed that this specimen belongs to L.jara.This discovery confirms the distribution of L.jara in China and expands the range of this species to the south edge of Gaoligong Mountains,and provides the first detailed morphological description of L.jara from China thus increasing the number of Lycodon species in China to 23.
基金supported by the National Key Research and Development Program(2019YFA0110800 and 2020YFA0707900 to W.L.and 2018YFA0108400 and 2019YFA0903800 to Q.Z.)the Strategic Priority Research Programof the Chinese Academy of Sciences(XDA16030403 to W.L.)+1 种基金the National Natural Science Foundation of China(31621004 to Q.Z.and W.L.)and the CAS Project for Young Scientists in Basic Research(YSBR-012 to W.L.).
文摘The naturally occurring prokaryotic CRISPR-Cas systems provide valuable resources for the development of new genome-editing tools.However,the majority of prokaryotic Cas nucleases exhibit poor editing efficiency in mammalian cells,which significantly limits their utility.Here,we have developed a method termed Improving Editing Activity by Synergistic Engineering(MIDAS).This method exerts a synergistic effect to improve mammalian genome-editing efficiency of a wide range of CRISPR-Cas systems by enhancing the interactions of Cas nuclease with the protospacer adjacent motif(PAM)and the single-stranded DNA(ssDNA)substrate in the catalytic pocket simultaneously.MIDAS robustly and significantly increased the gene-editing efficiency of Cas12i,Cas12b,and CasX in human cells.Notably,a Cas12i variant,Cas12iMax,exhibited robust activity with a very broad PAM range(NTNN,NNTN,NAAN,and NCAN)and higher efficiency than the current widely used Cas nucleases.A high-fidelity version of Cas12iMax(Cas12iHiFi)has been further engineered to minimize off-target effects.Our work provides an expandable and efficacious method for engineering Cas nucleases for robust mammalian genome editing.
基金supported by the National Natural Science Foundation of China(Grant Nos.42177448 and 41907393)。
文摘With growing regional economic integration,transportation systems have become critical to regional development and economic vitality but vulnerable to disasters.However,the regional economic ripple effect of a disaster is difficult to quantify accurately,especially considering the cumulated influence of traffic disruptions.This study explored integrating transportation system analysis with economic modeling to capture the regional economic ripple effect.A state-of-the-art spatial computable general equilibrium model is leveraged to simulate the operation of the economic system,and the marginal rate of transport cost is introduced to reflect traffic network damage post-disaster.The model is applied to the 50-year return period flood in2020 in Hubei Province,China.The results show the following.First,when traffic disruption costs are considered,the total output loss of non-affected areas is 1.81 times than before,and non-negligible losses reach relatively remote zones of the country,such as the Northwest Comprehensive Economic Zone(36%of total ripple effects).Second,traffic disruptions have a significant hindering effect on regional trade activities,especially in the regional intermediate input—about three times more than before.The industries most sensitive to traffic disruptions were transportation,storage,and postal service(5 times),and processing and assembly manufacturing(4.4 times).Third,the longer the distance,the stronger traffic disruptions'impact on interregional intermediate inputs.Thus,increasing investment in transportation infrastructure significantly contributes to mitigating disaster ripple effects and accelerating the process of industrial recovery in affected areas.
基金supported by the National Key Research and Development Program(2020YFA0707900,2018YFE0201100,2019YFA0110800 to W.L.,2018YFA0108400,2019YFA0903800 to Q.Z.)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA16030403 to W.L.)+1 种基金the National Natural Science Foundation of China(31621004 to Q.Z.and W.L.)the CAS Project for Young Scientists in Basic Research(YSBR-012 to W.L.)。
文摘Dear editor.The remarkably diversified CRISPR-Cas systems in nature have provided unlimited valuable resources to develop genome editing tools that are revolutionizing the fields of biotechnology and medicine.However,due to their microbial origin,the activity of most naturally occurring CRISPR-Cas nucleases is relatively poor in mammalian cells(Ran et al.,2015).Thus,improving the mammalian genome editing efficiency becomes the priority for harnessing more CRISPRCas systems for widespread applications.Rational protein engineering serves as a powerful approach to enhance the catalytic activity of enzymes.Whereas,this approach largely relies on proteinic three-dimension(3D)structure information as guide for design.The fact is that of the large numbers of the CRISPR-Cas systems discovered in recent years,only a small number of them with the 3D structures were reported.To bypass this limitation,here,we report an efficient and simple strategy for rational engineering of Cas nucleases without the need of 3D structure information and successfully optimized nucleases from Cas9 and Cas12 families.
基金supported by the National Key Research and Development Program(No.2021YFC3200803)the Scientific Research Project of China Three Gorges Corporation(No.201903139)+3 种基金the National Key R&D Program of China(No.2021YFC3200102)the National Natural Science Foundation of China(No.42007227)the National Natural Science Foundation of China(No.52030003)the Natural Science Foundation of Tianjin(No.22YFYSHZ00060).
文摘The global spread of viruses can lead to the release of large amounts of disinfectants or antiviral drugs into the water environment.The resulting disinfection byproducts(DBPs)and residual antiviral drugs,acting as genotoxic substances or their precursors,may pose risks to aquatic animals and drinking water sources;however,to date,no studies have analyzed the changes in genotoxicity in the Yangtze River before and after the epidemic.In the present study,water and sediment samples from the Yangtze River were collected during different seasons,just before and after the outbreak of COVID-19,and were assessed using the SOS/umu test(with and without liver S9).The results indicated that water samples exhibited more pronounced genotoxicity than did sediments,with direct genotoxicity being the primary factor.Additionally,there were significant regional differences,with notably greater genotoxicity observed in the upper Yangtze River than in the lower reaches before the COVID-19 epidemic.However,this trend was reversed six to ten months later,suggesting the accumulation of DBPs or antiviral drugs after the COVID-19 pandemic.Moreover,the risk quotient indicated that 65%of the water samples posed a high risk for Paramecium caudatum,whereas 71%of the samples posed a medium risk for Danio rerio,thereby representing a potential threat to the ecological security of the Yangtze River.In conclusion,this study,at the basin scale,revealed the impacts of COVID-19 on the Yangtze River,highlighting the need to prevent DBPs and pharmaceutical pollution during similar events in the future.
