研究野生型苏云金芽孢杆菌Cry1Aa和Cry1C的毒性变化发现,不同的pH不但影响这些蛋白质的毒性,而且影响它们在跨膜过程中形成孔洞的能九将 Cry1 Aa α4螺旋中的15个氨基酸突变后与BBMV结合,进行光散射分析,与野生型Cry1Aa相比较,发现有3...研究野生型苏云金芽孢杆菌Cry1Aa和Cry1C的毒性变化发现,不同的pH不但影响这些蛋白质的毒性,而且影响它们在跨膜过程中形成孔洞的能九将 Cry1 Aa α4螺旋中的15个氨基酸突变后与BBMV结合,进行光散射分析,与野生型Cry1Aa相比较,发现有3个突变体几乎完全失去毒性,7个突变体毒性明显降低,5个突变体保持野生型毒性.采用计算机模拟方法研究了苏云金芽孢杆菌Cry1Aa毒蛋白α4螺旋的三维空间结构,通过观察15个不同残基定点突变对其功能的影响,解释了突变体毒性变化的原因,说明了参与膜孔洞形成氨基酸残基对Cry1Aa昆虫毒杀性的重要作用.展开更多
Gypsy moth （Lymantria dispar） larvae displayed marked developmental resistance within an instar to L dispar M nucleopolyhedrovirus （LdMNPV） regardless of the route of infection （oral or intrahemocoelic） in a pre...Gypsy moth （Lymantria dispar） larvae displayed marked developmental resistance within an instar to L dispar M nucleopolyhedrovirus （LdMNPV） regardless of the route of infection （oral or intrahemocoelic） in a previous study, indicating that in gypsy moth, this resistance has a systemic component. In this study, gypsy moth larvae challenged with the Amsacta moorei entomopoxvirus （AMEV） showed developmental resistance within the fourth instar to oral, but not intrahemocoelic, inoculation. In general, gypsy moth is considered refractory to oral challenge with AMEV, but in this study, 43% mortality occurred in newly molted fourth instars fed a dose of 5×10^6 large spheroids of AMEV; large spheroids were found to be more infectious than small spheroids when separated by a sucrose gradient. Developmental resistance within the fourth instar was reflected by a 2-fold reduction in mortality （18%-21%） with 5 X 106 large spheroids in larvae orally challenged at 24, 48 or 72 h post-molt. Fourth instars were highly sensitive to intrahemocoelic challenge with AMEV; 1PFU produced approximately 80% mortality regardless of age within the instar. These results indicate that in gypsy moth, systemic developmental resistance may be specific to LdMNPV, reflecting a co-evolutionary relationship between the baculovirus and its host.展开更多
Hz-2V is one of only a very few sexually transmitted viruses currently known in insects. Replication of this insect pathogenic virus results in sterility of infected moths rather than mortality. The sterility of the i...Hz-2V is one of only a very few sexually transmitted viruses currently known in insects. Replication of this insect pathogenic virus results in sterility of infected moths rather than mortality. The sterility of the infected host is a consequence of virus directed malformation of adult reproductive tissues, which in females results in cellular proliferation and hypertrophy of these tissues. Virus replication has additional ramifications in infected females. Infected females produce more mating pheromones and attract more mates than healthy females, ultimately facilitating virus transmission and enhancing viral fitness. The molecular mechanisms used by the virus to manipulate the host to enhance its fitness are yet to be determined. Unraveling the underlying principles of these mechanisms promises to enhance our understanding of insect reproductive physiology, as well as provide molecular tools for use in novel approaches in sterile insect control programs.展开更多
Climatic variations are becoming important limiting factors for agriculture productivity,as they not only directly affect the plant net primary productivity but can also modulate the outbreak of plant diseases and pes...Climatic variations are becoming important limiting factors for agriculture productivity,as they not only directly affect the plant net primary productivity but can also modulate the outbreak of plant diseases and pests.Elevated CO_2 and O_3 are two important climatic factors that have been widely studied before.Elevated CO_2 or O_3 alters the host plant physiology and affects the vector insects and plant viruses via bottom-up effects of the host plants.Many studies have shown that elevated CO_2 or O_3 decreases the plant nitrogen content,which modulates the characteristics of vector insects.Recent evidence also reveals that hormone-dependent signaling pathways play a critical role in regulating the response of insects and plant viruses to elevated CO_2 or O_3.In the current review,we describe how elevated CO_2 or O_3 affects the vector insects and plant viruses by altering the SA and JA signaling pathways.We also discuss how changes in the feeding behavior of vector insects or the occurrence of plant viruses affects the interactions between vector insects and plant viruses under elevated CO_2 or O_3.We suggest that new insights into the upstream network that regulates hormone signaling and top-down effects of natural enemies would provide a comprehensive understanding of the complex interactions taking place under elevated CO_2 or O_3.展开更多
文摘研究野生型苏云金芽孢杆菌Cry1Aa和Cry1C的毒性变化发现,不同的pH不但影响这些蛋白质的毒性,而且影响它们在跨膜过程中形成孔洞的能九将 Cry1 Aa α4螺旋中的15个氨基酸突变后与BBMV结合,进行光散射分析,与野生型Cry1Aa相比较,发现有3个突变体几乎完全失去毒性,7个突变体毒性明显降低,5个突变体保持野生型毒性.采用计算机模拟方法研究了苏云金芽孢杆菌Cry1Aa毒蛋白α4螺旋的三维空间结构,通过观察15个不同残基定点突变对其功能的影响,解释了突变体毒性变化的原因,说明了参与膜孔洞形成氨基酸残基对Cry1Aa昆虫毒杀性的重要作用.
基金Partial funding for this project was provided by the National Science Foundation USA (Award No.IBN-0077710)
文摘Gypsy moth （Lymantria dispar） larvae displayed marked developmental resistance within an instar to L dispar M nucleopolyhedrovirus （LdMNPV） regardless of the route of infection （oral or intrahemocoelic） in a previous study, indicating that in gypsy moth, this resistance has a systemic component. In this study, gypsy moth larvae challenged with the Amsacta moorei entomopoxvirus （AMEV） showed developmental resistance within the fourth instar to oral, but not intrahemocoelic, inoculation. In general, gypsy moth is considered refractory to oral challenge with AMEV, but in this study, 43% mortality occurred in newly molted fourth instars fed a dose of 5×10^6 large spheroids of AMEV; large spheroids were found to be more infectious than small spheroids when separated by a sucrose gradient. Developmental resistance within the fourth instar was reflected by a 2-fold reduction in mortality （18%-21%） with 5 X 106 large spheroids in larvae orally challenged at 24, 48 or 72 h post-molt. Fourth instars were highly sensitive to intrahemocoelic challenge with AMEV; 1PFU produced approximately 80% mortality regardless of age within the instar. These results indicate that in gypsy moth, systemic developmental resistance may be specific to LdMNPV, reflecting a co-evolutionary relationship between the baculovirus and its host.
基金supported by the Cooperative State Research Extension, Education Service, U. S. Department of Agriculture, the Massachusetts Agri-cultural Experiment Station and the Department of Plant,Soil and Insect Sciences, under Project No. MAS00909
文摘Hz-2V is one of only a very few sexually transmitted viruses currently known in insects. Replication of this insect pathogenic virus results in sterility of infected moths rather than mortality. The sterility of the infected host is a consequence of virus directed malformation of adult reproductive tissues, which in females results in cellular proliferation and hypertrophy of these tissues. Virus replication has additional ramifications in infected females. Infected females produce more mating pheromones and attract more mates than healthy females, ultimately facilitating virus transmission and enhancing viral fitness. The molecular mechanisms used by the virus to manipulate the host to enhance its fitness are yet to be determined. Unraveling the underlying principles of these mechanisms promises to enhance our understanding of insect reproductive physiology, as well as provide molecular tools for use in novel approaches in sterile insect control programs.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB11050400)the National Natural Science Foundation of China(31370438)the R&D Special Fund for the Public Welfare Industry(201303019)
文摘Climatic variations are becoming important limiting factors for agriculture productivity,as they not only directly affect the plant net primary productivity but can also modulate the outbreak of plant diseases and pests.Elevated CO_2 and O_3 are two important climatic factors that have been widely studied before.Elevated CO_2 or O_3 alters the host plant physiology and affects the vector insects and plant viruses via bottom-up effects of the host plants.Many studies have shown that elevated CO_2 or O_3 decreases the plant nitrogen content,which modulates the characteristics of vector insects.Recent evidence also reveals that hormone-dependent signaling pathways play a critical role in regulating the response of insects and plant viruses to elevated CO_2 or O_3.In the current review,we describe how elevated CO_2 or O_3 affects the vector insects and plant viruses by altering the SA and JA signaling pathways.We also discuss how changes in the feeding behavior of vector insects or the occurrence of plant viruses affects the interactions between vector insects and plant viruses under elevated CO_2 or O_3.We suggest that new insights into the upstream network that regulates hormone signaling and top-down effects of natural enemies would provide a comprehensive understanding of the complex interactions taking place under elevated CO_2 or O_3.
