The disease of banana Fusarium wilt currently threatens banana production areas all over the world.Rapid and large-area monitoring of Fusarium wilt disease is very important for the disease treatment and crop planting...The disease of banana Fusarium wilt currently threatens banana production areas all over the world.Rapid and large-area monitoring of Fusarium wilt disease is very important for the disease treatment and crop planting adjustments.The objective of this study was to evaluate the performance of supervised classification algorithms such as support vector machine(SVM),random forest(RF),and artificial neural network(ANN)algorithms to identify locations that were infested or not infested with Fusarium wilt.An unmanned aerial vehicle(UAV)equipped with a five-band multi-spectral sensor(blue,green,red,red-edge and near-infrared bands)was used to capture the multi-spectral imagery.A total of 139 ground sample-sites were surveyed to assess the occurrence of banana Fusarium wilt.The results showed that the SVM,RF,and ANN algorithms exhibited good performance for identifying and mapping banana Fusarium wilt disease in UAV-based multi-spectral imagery.The overall accuracies of the SVM,RF,and ANN were 91.4%,90.0%,and 91.1%,respectively for the pixel-based approach.The RF algorithm required significantly less training time than the SVM and ANN algorithms.The maps generated by the SVM,RF,and ANN algorithms showed the areas of occurrence of Fusarium wilt disease were in the range of 5.21-5.75 hm2,accounting for 36.3%-40.1%of the total planting area of bananas in the study area.The results also showed that the inclusion of the red-edge band resulted in an increase in the overall accuracy of 2.9%-3.0%.A simulation of the resolutions of satellite-based imagery(i.e.,0.5 m,1 m,2 m,and 5 m resolutions)showed that imagery with a spatial resolution higher than 2 m resulted in good identification accuracy of Fusarium wilt.The results of this study demonstrate that the RF classifier is well suited for the identification and mapping of banana Fusarium wilt disease from UAV-based remote sensing imagery.The results provide guidance for disease treatment and crop planting adjustments.展开更多
The generation and application of replication-competent influenza A virus(IAV) expressing a reporter gene represent a valuable tool to elucidate the mechanism of viral pathogenesis and establish new countermeasures to...The generation and application of replication-competent influenza A virus(IAV) expressing a reporter gene represent a valuable tool to elucidate the mechanism of viral pathogenesis and establish new countermeasures to combat the threat of influenza. Here, replication-competent IAVs with a neuraminidase(NA) segment harboring a fluorescent reporter protein, Venus, were generated in the background of H5N1, H7N9, and H9N2 influenza viruses, the three subtypes of viruses with imminent pandemic potential. All three reporter viruses maintained virion morphology, replicated with similar or slightly reduced titers relative to their parental viruses, and stably expressed the fluorescent signal for at least two passages in embryonated chicken eggs. As a proof of concept, we demonstrated that these reporter viruses,used in combination with a high-content imaging system, can serve as a convenient and rapid tool for the screening of antivirals and host factors involved in the virus life cycle. Moreover, the reporter viruses demonstrated similar growth properties and tissue tropism as their parental viruses in mice, among which the H7N9 NA-Venus virus could potentially be used in ex vivo studies to better understand H7N9 pathogenesis or to develop novel therapeutics.展开更多
Cytokine storm induced by Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)is a major pathological feature of Coronavirus Disease 2019(COVID-19)and a crucial determinant in COVID-19 prognosis.Understanding t...Cytokine storm induced by Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)is a major pathological feature of Coronavirus Disease 2019(COVID-19)and a crucial determinant in COVID-19 prognosis.Understanding the mechanism underlying the SARS-CoV-2-induced cytokine storm is critical for COVID-19 control.Here,we identify that SARS-CoV-2 ORF3a and host hypoxia-inducible factor-1α(HIF-1α)play key roles in the virus infection and pro-inflammatory responses.展开更多
基金This research was funded by the Hainan Provincial Key R&D Program of China(ZDYF2018073)National Natural Science Foundation of China(41571354)+2 种基金Hainan Provincial Major Science and Technology Program of China(ZDKJ2019006)Agricultural Science and Technology Innovation of Sanya,China(2016NK16)National Special Support Program for High-level Personnel Recruitment(Ten-thousand Talents Program)(Wenjiang Huang),Innovation Foundation of Director of Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences.We also gratefully acknowledge the National Meteorological Information Center of China,Guangxi Jiejiarun Technology Co.,Ltd.and Guangxi Jinsui Agriculture Group Co.,Ltd.for the experiments.
文摘The disease of banana Fusarium wilt currently threatens banana production areas all over the world.Rapid and large-area monitoring of Fusarium wilt disease is very important for the disease treatment and crop planting adjustments.The objective of this study was to evaluate the performance of supervised classification algorithms such as support vector machine(SVM),random forest(RF),and artificial neural network(ANN)algorithms to identify locations that were infested or not infested with Fusarium wilt.An unmanned aerial vehicle(UAV)equipped with a five-band multi-spectral sensor(blue,green,red,red-edge and near-infrared bands)was used to capture the multi-spectral imagery.A total of 139 ground sample-sites were surveyed to assess the occurrence of banana Fusarium wilt.The results showed that the SVM,RF,and ANN algorithms exhibited good performance for identifying and mapping banana Fusarium wilt disease in UAV-based multi-spectral imagery.The overall accuracies of the SVM,RF,and ANN were 91.4%,90.0%,and 91.1%,respectively for the pixel-based approach.The RF algorithm required significantly less training time than the SVM and ANN algorithms.The maps generated by the SVM,RF,and ANN algorithms showed the areas of occurrence of Fusarium wilt disease were in the range of 5.21-5.75 hm2,accounting for 36.3%-40.1%of the total planting area of bananas in the study area.The results also showed that the inclusion of the red-edge band resulted in an increase in the overall accuracy of 2.9%-3.0%.A simulation of the resolutions of satellite-based imagery(i.e.,0.5 m,1 m,2 m,and 5 m resolutions)showed that imagery with a spatial resolution higher than 2 m resulted in good identification accuracy of Fusarium wilt.The results of this study demonstrate that the RF classifier is well suited for the identification and mapping of banana Fusarium wilt disease from UAV-based remote sensing imagery.The results provide guidance for disease treatment and crop planting adjustments.
基金supported by the National Natural Science Foundation of China(31472215,31521005,31422054,31402206)the National Key R&D Program of China(2016YFD0500205)
文摘The generation and application of replication-competent influenza A virus(IAV) expressing a reporter gene represent a valuable tool to elucidate the mechanism of viral pathogenesis and establish new countermeasures to combat the threat of influenza. Here, replication-competent IAVs with a neuraminidase(NA) segment harboring a fluorescent reporter protein, Venus, were generated in the background of H5N1, H7N9, and H9N2 influenza viruses, the three subtypes of viruses with imminent pandemic potential. All three reporter viruses maintained virion morphology, replicated with similar or slightly reduced titers relative to their parental viruses, and stably expressed the fluorescent signal for at least two passages in embryonated chicken eggs. As a proof of concept, we demonstrated that these reporter viruses,used in combination with a high-content imaging system, can serve as a convenient and rapid tool for the screening of antivirals and host factors involved in the virus life cycle. Moreover, the reporter viruses demonstrated similar growth properties and tissue tropism as their parental viruses in mice, among which the H7N9 NA-Venus virus could potentially be used in ex vivo studies to better understand H7N9 pathogenesis or to develop novel therapeutics.
基金This work was supported by the National Natural Science Foundation of China(81730061,81471942,and 32070148)Guangdong Province"Pearl River Talent Plan"Innovation and Entrepreneurship Team Project(2017ZT07Y580).
文摘Cytokine storm induced by Severe Acute Respiratory Syndrome Coronavirus 2(SARS-CoV-2)is a major pathological feature of Coronavirus Disease 2019(COVID-19)and a crucial determinant in COVID-19 prognosis.Understanding the mechanism underlying the SARS-CoV-2-induced cytokine storm is critical for COVID-19 control.Here,we identify that SARS-CoV-2 ORF3a and host hypoxia-inducible factor-1α(HIF-1α)play key roles in the virus infection and pro-inflammatory responses.