The Experts below are selected from a list of 11601 Experts worldwide ranked by ideXlab platform
Madoka Nakai - One of the best experts on this subject based on the ideXlab platform.
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Biological Control of Tortricidae in Tea Fields in Japan Using Insect Viruses and Parasitoids
Virologica Sinica, 2009Co-Authors: Madoka NakaiAbstract:Tea is a perennial and evergreen plant. Cultivated tea trees provide a habitat for Insect pests and their natural enemies. In Japan, granuloViruses (GVs) have successfully controlled two of the most important pests of tea, Adoxophyes honmai and Homona magnanima (Tortricidae: Lepidoptera). The GVs are produced in vivo and a single application sustains pesticidal efficacy throughout a year, which encompasses 4 to 5 discrete generations of both species. A. honmai and H. magnanima also have various natural enemies, especially hymenopteran parasitoids. Such resident natural enemies also play a role in reducing the pest density in virus-controlled fields, but the effect of virus infection on parasitoids sharing the same host larva has not been well studied. Survival of one of the major parasitoids of A. honmai, Ascogaster reticulata (Braconidae: Hymenoptera), is reduced by virus infection of the host. Viruses, including GV and entomopoxvirus (EPV), and certain koinobiont endoparasitoids, including A. reticulata, are both known to regulate host endocrinology. However, the GV and EPV have distinct host regulation mechanisms, and consequently have different impacts on the survival of A. retuculata, when A. reticulata parasitizes a host that is infected with either GV or EPV. These additional effects on host regulation displayed by both Viruses and parasitoids affect the outcome of virus-parasitoid interactions.
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Biological Control of Tortricidae in Tea Fields in Japan Using Insect Viruses and Parasitoids
Virologica Sinica, 2009Co-Authors: Madoka NakaiAbstract:Tea is a perennial and evergreen plant. Cultivated tea trees provide a habitat for Insect pests and their natural enemies. In Japan, granuloViruses (GVs) have successfully controlled two of the most important pests of tea, Adoxophyes honmai and Homona magnanima (Tortricidae: Lepidoptera). The GVs are produced in vivo and a single application sustains pesticidal efficacy throughout a year, which encompasses 4 to 5 discrete generations of both species. A. honmai and H. magnanima also have various natural enemies, especially hymenopteran parasitoids. Such resident natural enemies also play a role in reducing the pest density in virus-controlled fields, but the effect of virus infection on parasitoids sharing the same host larva has not been well studied. Survival of one of the major parasitoids of A. honmai, Ascogaster reticulata (Braconidae: Hymenoptera), is reduced by virus infection of the host. Viruses, including GV and entomopoxvirus (EPV), and certain koinobiont endoparasitoids, including A. reticulata, are both known to regulate host endocrinology. However, the GV and EPV have distinct host regulation mechanisms, and consequently have different impacts on the survival of A. retuculata, when A. reticulata parasitizes a host that is infected with either GV or EPV. These additional effects on host regulation displayed by both Viruses and parasitoids affect the outcome of virus-parasitoid interactions.
Sassan Asgari - One of the best experts on this subject based on the ideXlab platform.
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The role of actin filaments in ascovirus replication and pathology
Archives of Virology, 2009Co-Authors: Mazhar Hussain, Steven Garrad, Sassan AsgariAbstract:AscoViruses (AVs) are Insect Viruses transmitted by parasitoid wasps. The unique pathology in host cells upon AV infection includes enlargement, blebbing and cleavage of host cells into virus-containing vesicles that are important in dissemination of the virus. The mechanism of pathogenesis and vesicle formation is largely unknown. Here, we explored involvement of actin filaments in virus entry, replication and pathology. The results suggested that entry of Heliothis virescens ascovirus-3e (HvAV-3e) leads to rearrangement of the actin cytoskeleton. After HvAV-3e infection, actin filaments were found in foci rather than in a homogenous distribution within the cytoplasm. Actin filaments were also found concentrating around blebs and vesiculation areas of the cell cortex following infection. Destabilization of filamentous actin by cytochalasin D did not inhibit entry or replication of the virus but affected vesiculation and pathology associated with HvAV-3e infection. These observations suggested that actin may not be required for virus entry and replication but essential for virus pathology, mainly vesicle formation.
Hajime Mori - One of the best experts on this subject based on the ideXlab platform.
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3D co-cultures of keratinocytes and melanocytes and cytoprotective effects on keratinocytes against reactive oxygen species by Insect virus-derived protein microcrystals
Materials Science and Engineering: C, 2014Co-Authors: Junji Shimabukuro, Ayako Yamaoka, Ken Ichi Murata, Eiji Kotani, Tomoko Hirano, Yumiko Nakajima, Goichi Matsumoto, Hajime MoriAbstract:Abstract Stable protein microcrystals called polyhedra are produced by certain Insect Viruses. Cytokines, such as fibroblast growth factors (FGFs), can be immobilized within polyhedra. Here, we investigated three-dimensional (3D) co-cultures of keratinocytes and melanocytes on collagen gel containing FGF-2 and FGF-7 polyhedra. Melanocytes were observed to reside at the base of the 3D cell culture and melanin was also typically observed in the lower layer. The 3D cell culture model with FGF-2 and FGF-7 polyhedra was a useful in vitro model of the epidermis due to effective melanogenesis, proliferation and differentiation of keratinocytes. FGF-7 polyhedra showed a potent cytoprotective effect when keratinocytes were treated with menadione, which is a generator of reactive oxygen species. The cytoprotective effect was activated by the inositol triphosphate kinase–Akt pathway leading to upregulation of the antioxidant enzymes superoxide dismutase and peroxiredoxin 6.
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mutations of cypovirus polyhedrin and applications of polyhedra to protein nanocontainers
Nanotechnology Conference and Trade Show (Nanotech) 2010, 2010Co-Authors: Y Ohtsuka, Daisuke Nakai, F Coulibaly, Yui Cooper, Peter Metcalf, Hajime MoriAbstract:CypoViruses are Insect Viruses that produce micrometersized protein crystals called polyhedra. Virus particles are occluded in polyhedra. Recently we have developed a novel method for protein immobilization into polyhedra. It is possible to use these polyhedra to device ultra-stable protein nanocontainers. However, a weak point of them is that polyhedra dissolve only in high pH condition (pH>10.5). It seems important to carry out structure-based engineering of polyhedrin to derive mutants for multiple purposes. At a packing contact, we have identified a cluster of tyrosine (Fig. 1), deprotonation of which is likely to cause disruption of the lattice at alkaline pH. In this study, we substituted these tyrosine residues by other amino acids. We show that the substitutions of some residues in a cluster of tyrosine lead to modify a solubility of polyhedra. The results suggest that the modified polyhedra can serve as the basis for the development of nanoparticles for biotechnological applications.
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The atomic structure of baculovirus polyhedra reveals the independent emergence of infectious crystals in DNA and RNA Viruses
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Fasseli Joseph Coulibaly, E. Chiu, Sascha Gutmann, Chitra Rajendran, Peter W. Haebel, Keiko D Ikeda, Vernon K Ward, Clemens Schulze-briese, Hajime Mori, Peter MetcalfAbstract:Abstract BaculoViruses are ubiquitous Insect Viruses well known for their use as bioInsecticides, gene therapy vectors, and protein expression systems. Overexpression of recombinant proteins in Insect cell culture utilizes the strong promoter of the polyhedrin gene. In infected larvae, the polyhedrin protein forms robust intracellular crystals called polyhedra, which protect encased virions for prolonged periods in the environment. Polyhedra are produced by two unrelated families of Insect Viruses, baculoViruses and cypoViruses. The atomic structure of cypovirus polyhedra revealed an intricate packing of trimers, which are interconnected by a projecting N-terminal helical arm of the polyhedrin molecule. Baculovirus and cypovirus polyhedra share nearly identical lattices, and the N-terminal region of the otherwise unrelated baculovirus polyhedrin protein sequence is also predicted to be α-helical. These results suggest homology between the proteins and a common structural basis for viral polyhedra. Here, we present the 2.2-A structure of baculovirus polyhedra determined by x-ray crystallography from microcrystals produced in vivo. We show that the underlying molecular organization is, in fact, very different. Although both polyhedra have nearly identical unit cell dimensions and share I23 symmetry, the polyhedrin molecules are structurally unrelated and pack differently in the crystals. In particular, disulfide bonds and domain-swapped N-terminal domains stabilize the building blocks of baculovirus polyhedra and interlocking C-terminal arms join unit cells together. We show that the N-terminal projecting helical arms have different structural roles in baculovirus and cypovirus polyhedra and conclude that there is no structural evidence for a common evolutionary origin for both classes of polyhedra.
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The molecular organization of cypovirus polyhedra
Nature, 2007Co-Authors: Fasseli Joseph Coulibaly, E. Chiu, Sascha Gutmann, Peter W. Haebel, Clemens Schulze-briese, Hajime Mori, Keiko Ikeda, Peter MetcalfAbstract:Insect Viruses that produce infectious polyhedra — crystals encapsulating thousands of virus particles — are widespread and important. The polyhedra microcrystals are remarkably stable, which can cause disease persistence, threatening silkworm cocoon harvests for instance. The molecular structure of one of these crystals has now been determined. This is a major technical feat in protein X-ray microcrystallography, as these Viruses are the smallest protein crystals ever used to determine atomic structure. The study reveals robust polyhedra that could be useful as delivery capsules for biopesticides and for nanobiotechnology applications such as microarrays. CypoViruses and baculoViruses are notoriously difficult to eradicate because the virus particles are embedded in micrometre-sized protein crystals called polyhedra1,2. The remarkable stability of polyhedra means that, like bacterial spores, these Insect Viruses remain infectious for years in soil. The environmental persistence of polyhedra is the cause of significant losses in silkworm cocoon harvests but has also been exploited against pests in biological alternatives to chemical Insecticides3,4. Although polyhedra have been extensively characterized since the early 1900s5, their atomic organization remains elusive6. Here we describe the 2 A crystal structure of both recombinant and infectious silkworm cypovirus polyhedra determined using crystals 5–12 micrometres in diameter purified from Insect cells. These are the smallest crystals yet used for de novo X-ray protein structure determination7. We found that polyhedra are made of trimers of the viral polyhedrin protein and contain nucleotides. Although the shape of these building blocks is reminiscent of some capsid trimers, polyhedrin has a new fold and has evolved to assemble in vivo into three-dimensional cubic crystals rather than icosahedral shells. The polyhedrin trimers are extensively cross-linked in polyhedra by non-covalent interactions and pack with an exquisite molecular complementarity similar to that of antigen–antibody complexes. The resulting ultrastable and sealed crystals shield the virus particles from environmental damage. The structure suggests that polyhedra can serve as the basis for the development of robust and versatile nanoparticles for biotechnological applications8 such as microarrays9 and biopesticides4.
H C J Godfrav - One of the best experts on this subject based on the ideXlab platform.
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field experiments with genetically manipulated Insect Viruses ecological issues
Trends in Ecology and Evolution, 1995Co-Authors: H C J GodfravAbstract:Evil Oxford scientists, bent on world domination, release virus containing scorpion poison gene into English countryside. Well, not quite; but readers of the British press last summer might be forgiven for thinking that a latter-day Central Anarchist Council had taken root among the dreaming spires. The press reports concerned field experiments near Oxford of a genetically manipulated Insect baculovirus by the National Environmental Research Council's (NERC) Institute for Virology and Environmental Microbiology (IVEM). But while it is easy to smile at sensational headlines, at least some of the press reporting has been accurate and informed, and raises important ecological issues - as well as questions about the regulation of experiments with genetically manipulated organisms.
Peter Metcalf - One of the best experts on this subject based on the ideXlab platform.
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mutations of cypovirus polyhedrin and applications of polyhedra to protein nanocontainers
Nanotechnology Conference and Trade Show (Nanotech) 2010, 2010Co-Authors: Y Ohtsuka, Daisuke Nakai, F Coulibaly, Yui Cooper, Peter Metcalf, Hajime MoriAbstract:CypoViruses are Insect Viruses that produce micrometersized protein crystals called polyhedra. Virus particles are occluded in polyhedra. Recently we have developed a novel method for protein immobilization into polyhedra. It is possible to use these polyhedra to device ultra-stable protein nanocontainers. However, a weak point of them is that polyhedra dissolve only in high pH condition (pH>10.5). It seems important to carry out structure-based engineering of polyhedrin to derive mutants for multiple purposes. At a packing contact, we have identified a cluster of tyrosine (Fig. 1), deprotonation of which is likely to cause disruption of the lattice at alkaline pH. In this study, we substituted these tyrosine residues by other amino acids. We show that the substitutions of some residues in a cluster of tyrosine lead to modify a solubility of polyhedra. The results suggest that the modified polyhedra can serve as the basis for the development of nanoparticles for biotechnological applications.
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The atomic structure of baculovirus polyhedra reveals the independent emergence of infectious crystals in DNA and RNA Viruses
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Fasseli Joseph Coulibaly, E. Chiu, Sascha Gutmann, Chitra Rajendran, Peter W. Haebel, Keiko D Ikeda, Vernon K Ward, Clemens Schulze-briese, Hajime Mori, Peter MetcalfAbstract:Abstract BaculoViruses are ubiquitous Insect Viruses well known for their use as bioInsecticides, gene therapy vectors, and protein expression systems. Overexpression of recombinant proteins in Insect cell culture utilizes the strong promoter of the polyhedrin gene. In infected larvae, the polyhedrin protein forms robust intracellular crystals called polyhedra, which protect encased virions for prolonged periods in the environment. Polyhedra are produced by two unrelated families of Insect Viruses, baculoViruses and cypoViruses. The atomic structure of cypovirus polyhedra revealed an intricate packing of trimers, which are interconnected by a projecting N-terminal helical arm of the polyhedrin molecule. Baculovirus and cypovirus polyhedra share nearly identical lattices, and the N-terminal region of the otherwise unrelated baculovirus polyhedrin protein sequence is also predicted to be α-helical. These results suggest homology between the proteins and a common structural basis for viral polyhedra. Here, we present the 2.2-A structure of baculovirus polyhedra determined by x-ray crystallography from microcrystals produced in vivo. We show that the underlying molecular organization is, in fact, very different. Although both polyhedra have nearly identical unit cell dimensions and share I23 symmetry, the polyhedrin molecules are structurally unrelated and pack differently in the crystals. In particular, disulfide bonds and domain-swapped N-terminal domains stabilize the building blocks of baculovirus polyhedra and interlocking C-terminal arms join unit cells together. We show that the N-terminal projecting helical arms have different structural roles in baculovirus and cypovirus polyhedra and conclude that there is no structural evidence for a common evolutionary origin for both classes of polyhedra.
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The molecular organization of cypovirus polyhedra
Nature, 2007Co-Authors: Fasseli Joseph Coulibaly, E. Chiu, Sascha Gutmann, Peter W. Haebel, Clemens Schulze-briese, Hajime Mori, Keiko Ikeda, Peter MetcalfAbstract:Insect Viruses that produce infectious polyhedra — crystals encapsulating thousands of virus particles — are widespread and important. The polyhedra microcrystals are remarkably stable, which can cause disease persistence, threatening silkworm cocoon harvests for instance. The molecular structure of one of these crystals has now been determined. This is a major technical feat in protein X-ray microcrystallography, as these Viruses are the smallest protein crystals ever used to determine atomic structure. The study reveals robust polyhedra that could be useful as delivery capsules for biopesticides and for nanobiotechnology applications such as microarrays. CypoViruses and baculoViruses are notoriously difficult to eradicate because the virus particles are embedded in micrometre-sized protein crystals called polyhedra1,2. The remarkable stability of polyhedra means that, like bacterial spores, these Insect Viruses remain infectious for years in soil. The environmental persistence of polyhedra is the cause of significant losses in silkworm cocoon harvests but has also been exploited against pests in biological alternatives to chemical Insecticides3,4. Although polyhedra have been extensively characterized since the early 1900s5, their atomic organization remains elusive6. Here we describe the 2 A crystal structure of both recombinant and infectious silkworm cypovirus polyhedra determined using crystals 5–12 micrometres in diameter purified from Insect cells. These are the smallest crystals yet used for de novo X-ray protein structure determination7. We found that polyhedra are made of trimers of the viral polyhedrin protein and contain nucleotides. Although the shape of these building blocks is reminiscent of some capsid trimers, polyhedrin has a new fold and has evolved to assemble in vivo into three-dimensional cubic crystals rather than icosahedral shells. The polyhedrin trimers are extensively cross-linked in polyhedra by non-covalent interactions and pack with an exquisite molecular complementarity similar to that of antigen–antibody complexes. The resulting ultrastable and sealed crystals shield the virus particles from environmental damage. The structure suggests that polyhedra can serve as the basis for the development of robust and versatile nanoparticles for biotechnological applications8 such as microarrays9 and biopesticides4.