The Experts below are selected from a list of 71559 Experts worldwide ranked by ideXlab platform
Gregory D Ebel - One of the best experts on this subject based on the ideXlab platform.
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the west nile Virus Mutant spectrum is host dependant and a determinant of mortality in mice
Virology, 2007Co-Authors: Greta V S Jerzak, Laura D. Kramer, Kristen A Bernard, Pei Yong Shi, Gregory D EbelAbstract:To define the impact of mosquitoes and birds on intrahost WNV population dynamics, the Mutant spectra that arose as a result of 20 serial in vivo passages in Culex pipiens and young chickens were examined. Genetically homogeneous WNV was serially passaged 20 times in each host. Genetic diversity was greater in mosquito-passaged WNV compared to chicken-passaged WNV. Changes in the viral consensus sequence occurred in WNV passaged in mosquitoes earlier and more frequently than in chicken-passaged WNV. Analysis of synonymous and nonsynonymous variation suggested that purifying selection was relaxed during passage in mosquitoes. Mortality in mice was significantly negatively correlated with the size of the WNV Mutant spectrum. These studies suggest that mosquitoes serve as sources for WNV genetic diversity, that birds are selective sieves, and that both the consensus sequence and the Mutant spectrum contribute to WNV phenotype.
Laura D. Kramer - One of the best experts on this subject based on the ideXlab platform.
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Cooperative interactions in the West Nile Virus Mutant swarm
BMC evolutionary biology, 2012Co-Authors: Alexander T. Ciota, Dylan Ehrbar, Greta Van Slyke, Graham G. Willsey, Laura D. KramerAbstract:Background RNA Viruses including arthropod-borne Viruses (arboViruses) exist as highly genetically diverse Mutant swarms within individual hosts. A more complete understanding of the phenotypic correlates of these diverse swarms is needed in order to equate RNA swarm breadth and composition to specific adaptive and evolutionary outcomes.
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the west nile Virus Mutant spectrum is host dependant and a determinant of mortality in mice
Virology, 2007Co-Authors: Greta V S Jerzak, Laura D. Kramer, Kristen A Bernard, Pei Yong Shi, Gregory D EbelAbstract:To define the impact of mosquitoes and birds on intrahost WNV population dynamics, the Mutant spectra that arose as a result of 20 serial in vivo passages in Culex pipiens and young chickens were examined. Genetically homogeneous WNV was serially passaged 20 times in each host. Genetic diversity was greater in mosquito-passaged WNV compared to chicken-passaged WNV. Changes in the viral consensus sequence occurred in WNV passaged in mosquitoes earlier and more frequently than in chicken-passaged WNV. Analysis of synonymous and nonsynonymous variation suggested that purifying selection was relaxed during passage in mosquitoes. Mortality in mice was significantly negatively correlated with the size of the WNV Mutant spectrum. These studies suggest that mosquitoes serve as sources for WNV genetic diversity, that birds are selective sieves, and that both the consensus sequence and the Mutant spectrum contribute to WNV phenotype.
John P Carr - One of the best experts on this subject based on the ideXlab platform.
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a cucumber mosaic Virus Mutant lacking the 2b counter defence protein gene provides protection against wild type strains
Journal of General Virology, 2007Co-Authors: Heiko Ziebell, Tina Payne, James O Berry, John A Walsh, John P CarrAbstract:Several plant Virus Mutants, in which genes encoding silencing suppressor proteins have been deleted, are known to induce systemic or localized RNA silencing against themselves and other RNA molecules containing homologous sequences. Thus, it is thought that many cases of cross-protection, in which infection with a mild or asymptomatic Virus Mutant protects plants against challenge infection with closely related virulent Viruses, can be explained by RNA silencing. We found that a cucumber mosaic Virus (CMV) Mutant of the subgroup IA strain Fny (Fny-CMVΔ2b), which cannot express the 2b silencing suppressor protein, cross-protects tobacco (Nicotiana tabacum) and Nicotiana benthamiana plants against disease induction by wild-type Fny-CMV. However, protection is most effective only if inoculation with Fny-CMVΔ2b and challenge inoculation with wild-type CMV occurs on the same leaf. Unexpectedly, Fny-CMVΔ2b also protected plants against infection with TC-CMV, a subgroup II strain that is not closely related to Fny-CMV. Additionally, in situ hybridization revealed that Fny-CMVΔ2b and Fny-CMV can co-exist in the same tissues but these tissues contain zones of Fny-CMVΔ2b-infected host cells from which Fny-CMV appears to be excluded. Taken together, it appears unlikely that cross-protection by Fny-CMVΔ2b occurs by induction of systemic RNA silencing against itself and homologous RNA sequences in wild-type CMV. It is more likely that protection occurs through either induction of very highly localized RNA silencing, or by competition between strains for host cells or resources.
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A cucumber mosaic Virus Mutant lacking the 2b counter-defence protein gene provides protection against wild-type strains.
The Journal of general virology, 2007Co-Authors: Heiko Ziebell, Tina Payne, James O Berry, John A Walsh, John P CarrAbstract:Several plant Virus Mutants, in which genes encoding silencing suppressor proteins have been deleted, are known to induce systemic or localized RNA silencing against themselves and other RNA molecules containing homologous sequences. Thus, it is thought that many cases of cross-protection, in which infection with a mild or asymptomatic Virus Mutant protects plants against challenge infection with closely related virulent Viruses, can be explained by RNA silencing. We found that a cucumber mosaic Virus (CMV) Mutant of the subgroup IA strain Fny (Fny-CMVDelta2b), which cannot express the 2b silencing suppressor protein, cross-protects tobacco (Nicotiana tabacum) and Nicotiana benthamiana plants against disease induction by wild-type Fny-CMV. However, protection is most effective only if inoculation with Fny-CMVDelta2b and challenge inoculation with wild-type CMV occurs on the same leaf. Unexpectedly, Fny-CMVDelta2b also protected plants against infection with TC-CMV, a subgroup II strain that is not closely related to Fny-CMV. Additionally, in situ hybridization revealed that Fny-CMVDelta2b and Fny-CMV can co-exist in the same tissues but these tissues contain zones of Fny-CMVDelta2b-infected host cells from which Fny-CMV appears to be excluded. Taken together, it appears unlikely that cross-protection by Fny-CMVDelta2b occurs by induction of systemic RNA silencing against itself and homologous RNA sequences in wild-type CMV. It is more likely that protection occurs through either induction of very highly localized RNA silencing, or by competition between strains for host cells or resources.
Christine Harley - One of the best experts on this subject based on the ideXlab platform.
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Wild-Type Coat Protein Gene of Tobacco Mosaic Virus Mutant Ni 2519
Journal of General Virology, 1993Co-Authors: David Zimmern, Teo Chor Hiang, Christine HarleyAbstract:Tobacco mosaic Virus Mutant Ni 2519 has a selected temperature-sensitive defect in the spreading of local lesions, and additional reported defects in Virus assembly and in host range. Here we show that the temperature-sensitive local lesion-spreading defect (which maps in the assembly origin within the gene encoding protein p30) is probably independent of mutations in the pseudoassembly origin or of host range defects resulting from other mutations in the coat protein. One new host range Mutant has been isolated.
Yoshiaki Ueda - One of the best experts on this subject based on the ideXlab platform.
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Identification and characterization of the thymidine kinase gene of
2016Co-Authors: Yaba Virus, Hiroko Amano, Yoshiaki Ueda, Tatsuo MiyamuraAbstract:DNA of Yaba Virus, a member of the poxViruses, was mapped by cross-hybridization between fragments of various restriction enzymes. The genome was approxi-mately 13 5 kb in length and possessed two characteristic features of poxViruses: cross-links and inverted terminal repeats at both termini. Hybridization of fragments of Yaba Virus DNA to known vaccinia Virus DNA fragments indicated that the thymidine kinase (TK) gene mapped within the 0.9 kb XhoI-HincI I fragment between 52"5 and 53'5 kb from the left end of the genome. The fragment could rescue the TK + phenotype in TK cells preinfected with a TK vaccinia Virus Mutant. Nucleotide sequencing of the fragment revealed an ORF capable of encoding 181 amino acids. The sequence TAAAAATG-AAAAATTA upstream of the ORF was considered to be the promoter and the downstream sequence TTTT-TAT to be the early transcription termination signal. These sequences are in good accord with the consensus regulatory sequences for the expression of early genes of other known poxViruses. The amino acid sequence similarity among the poxVirus TK genes suggests that Yaba Virus is most closely related to swinepox Virus and less similar to fowlpox Virus
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Identification and characterization of the thymidine kinase gene of
1995Co-Authors: Hiroko Amano, Yoshiaki UedaAbstract:DNA of Yaba Virus, a member of the poxViruses, was mapped by cross-hybridization between fragments of various restriction enzymes. The genome was approximately 13 5 kb in length and possessed two characteristic features of poxViruses: cross-links and inverted terminal repeats at both termini. Hybridization of fragments of Yaba Virus DNA to known vaccinia Virus DNA fragments indicated that the thymidine kinase (TK) gene mapped within the 0.9 kb XhoI-HincII fragment between 52"5 and 53'5 kb from the left end of the genome. The fragment could rescue the TK + phenotype in TK cells preinfected with a TK vaccinia Virus Mutant. Nucleotide sequencing of the fragment revealed an ORF capable of encoding 181 amino acids. The sequence TAAAAATGAAAAATTA upstream of the ORF was considered to be the promoter and the downstream sequence TTTTTAT to be the early transcription termination signal. These sequences are in good accord with the consensus regulatory sequences for the expression of early genes of other known poxViruses. The amino acid sequence similarity among the poxVirus TK genes suggests that Yaba Virus is most closely related to swinepox Virus and
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Identification and characterization of the thymidine kinase gene of Yaba Virus.
Journal of General Virology, 1995Co-Authors: Hiroko Amano, Yoshiaki UedaAbstract:DNA of Yaba Virus, a member of the poxViruses, was mapped by cross-hybridization between fragments of various restriction enzymes. The genome was approximately 135 kb in length and possessed two characteristic features of poxViruses: cross-links and inverted terminal repeats at both termini. Hybridization of fragments of Yaba Virus DNA to known vaccinia Virus DNA fragments indicated that the thymidine kinase (TK) gene mapped within the 0.9 kb XhoI-HincII fragment between 52.5 and 53.5 kb from the left end of the genome. The fragment could rescue the TK+ phenotype in TK- cells preinfected with a TK vaccinia Virus Mutant. Nucleotide sequencing of the fragment revealed an ORF capable of encoding 181 amino acids. The sequence TAAAAATGAAAAATTA upstream of the ORF was considered to be the promoter and the downstream sequence TTTTTAT to be the early transcription termination signal. These sequences are in good accord with the consensus regulatory sequences for the expression of early genes of other known poxViruses. The amino acid sequence similarity among the poxVirus TK genes suggests that Yaba Virus is most closely related to swinepox Virus and less similar to fowlpox Virus.
