The Experts below are selected from a list of 133482 Experts worldwide ranked by ideXlab platform
Kevin G.j. Pollock - One of the best experts on this subject based on the ideXlab platform.
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An outbreak of mumps with Genetic Strain variation in a highly vaccinated student population in Scotland.
Epidemiology and infection, 2017Co-Authors: L.j. Willocks, D. Guerendiain, H. I. Austin, K. E. Morrison, R. L. Cameron, Kate Templeton, V. R. F. De Lima, R. Ewing, W. Donovan, Kevin G.j. PollockAbstract:An outbreak of mumps within a student population in Scotland was investigated to assess the effect of previous vaccination on infection and clinical presentation, and any genotypic variation. Of the 341 cases, 79% were aged 18-24. Vaccination status was available for 278 cases of whom 84% had received at least one dose of mumps containing vaccine and 62% had received two. The complication rate was 5·3% (mainly orchitis), and 1·2% were admitted to hospital. Genetic sequencing of mumps virus isolated from cases across Scotland classified 97% of the samples as genotype G. Two distinct clusters of genotype G were identified, one circulating before the outbreak and the other thereafter, suggesting the virus that caused this outbreak was Genetically different from the previously circulating virus. Whilst the poor vaccine effectiveness we found may be due to waning immunity over time, a contributing factor may be that the current mumps vaccine is less effective against some genotypes. Although the general benefits of the measles-mumps-rubella (MMR) vaccine should continue to be promoted, there may be value in reassessing the UK vaccination schedule and the current mumps component of the MMR vaccine.
F Ponz - One of the best experts on this subject based on the ideXlab platform.
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Characterization of typical pepper-isolates of PVY reveals multiple pathotypes within a single Genetic Strain.
Virus research, 2001Co-Authors: A Romero, B Blanco-urgoiti, M J Soto, A Fereres, F PonzAbstract:Potato virus Y (PVY) isolates originally coming from infected pepper plants, were biologically and Genetically characterized, especially in comparison with PVY potato-isolates. Pepper PVY isolates could be differentiated from potato isolates in their host range, aphid transmission efficiencies, Mab serology, and Genetic status. The Genetic distances estimated for PVY pepper-isolates, based on their restrictotypes with five restriction enzymes and on their coat protein gene sequences, indicated that they form a single Genetic Strain with different pathotypic properties. This situation is essentially different to that of PVY potato-isolates.
Brendan Rodoni - One of the best experts on this subject based on the ideXlab platform.
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The Incidence and Genetic Diversity of Apple Mosaic Virus (ApMV) and Prune Dwarf Virus (PDV) in Prunus Species in Australia
Viruses, 2018Co-Authors: Wycliff M. Kinoti, N. Nancarrow, Fiona E. Constable, Kim M Plummer, Brendan RodoniAbstract:Apple mosaic virus (ApMV) and prune dwarf virus (PDV) are amongst the most common viruses infecting Prunus species worldwide but their incidence and Genetic diversity in Australia is not known. In a survey of 127 Prunus tree samples collected from five states in Australia, ApMV and PDV occurred in 4 (3%) and 13 (10%) of the trees respectively. High-throughput sequencing (HTS) of amplicons from partial conserved regions of RNA1, RNA2, and RNA3, encoding the methyltransferase (MT), RNA-dependent RNA polymerase (RdRp), and the coat protein (CP) genes respectively, of ApMV and PDV was used to determine the Genetic diversity of the Australian isolates of each virus. PhyloGenetic comparison of Australian ApMV and PDV amplicon HTS variants and full length genomes of both viruses with isolates occurring in other countries identified Genetic Strains of each virus occurring in Australia. A single Australian Prunus infecting ApMV Genetic Strain was identified as all ApMV isolates sequence variants formed a single phyloGenetic group in each of RNA1, RNA2, and RNA3. Two Australian PDV Genetic Strains were identified based on the combination of observed phyloGenetic groups in each of RNA1, RNA2, and RNA3 and one Prunus tree had both Strains. The accuracy of amplicon sequence variants phyloGenetic analysis based on segments of each virus RNA were confirmed by phyloGenetic analysis of full length genome sequences of Australian ApMV and PDV isolates and all published ApMV and PDV genomes from other countries.
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Analysis of intra-host Genetic diversity of Prunus necrotic ringspot virus (PNRSV) using amplicon next generation sequencing.
PLOS ONE, 2017Co-Authors: Wycliff M. Kinoti, N. Nancarrow, Fiona E. Constable, Kim M Plummer, Brendan RodoniAbstract:PCR amplicon next generation sequencing (NGS) analysis offers a broadly applicable and targeted approach to detect populations of both high- or low-frequency virus variants in one or more plant samples. In this study, amplicon NGS was used to explore the diversity of the tripartite genome virus, Prunus necrotic ringspot virus (PNRSV) from 53 PNRSV-infected trees using amplicons from conserved gene regions of each of PNRSV RNA1, RNA2 and RNA3. Sequencing of the amplicons from 53 PNRSV-infected trees revealed differing levels of polymorphism across the three different components of the PNRSV genome with a total number of 5040, 2083 and 5486 sequence variants observed for RNA1, RNA2 and RNA3 respectively. The RNA2 had the lowest diversity of sequences compared to RNA1 and RNA3, reflecting the lack of flexibility tolerated by the replicase gene that is encoded by this RNA component. Distinct PNRSV phylo-groups, consisting of closely related clusters of sequence variants, were observed in each of PNRSV RNA1, RNA2 and RNA3. Most plant samples had a single phylo-group for each RNA component. Haplotype network analysis showed that smaller clusters of PNRSV sequence variants were Genetically connected to the largest sequence variant cluster within a phylo-group of each RNA component. Some plant samples had sequence variants occurring in multiple PNRSV phylo-groups in at least one of each RNA and these phylo-groups formed distinct clades that represent PNRSV Genetic Strains. Variants within the same phylo-group of each Prunus plant sample had ≥97% similarity and phylo-groups within a Prunus plant sample and between samples had less ≤97% similarity. Based on the analysis of diversity, a definition of a PNRSV Genetic Strain was proposed. The proposed definition was applied to determine the number of PNRSV Genetic Strains in each of the plant samples and the complexity in defining Genetic Strains in multipartite genome viruses was explored.
J Schubert - One of the best experts on this subject based on the ideXlab platform.
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Discussion paper: The naming of Potato virus Y Strains infecting potato
Archives of Virology, 2008Co-Authors: R P Singh, S. M. Gray, C Kerlan, R A C Jones, Jari P. T. Valkonen, Neil Boonham, J SchubertAbstract:Potato virus Y (PVY) Strain groups are based on host response and resistance gene interactions. The Strain groups PVY(O), PVY(C) and PVY(N) are well established for the isolates infecting potato in the field. A switch in the emphasis from host response to nucleotide sequence differences in the virus genomes, detection of isolates recombining sequences of different Strains, and the need to recognize isolates that cause necrotic symptoms in potato tubers have led to the assignment of new acronyms, especially to isolates of the PVY(N) Strain group. This discussion paper proposes that any newly found isolates should be described within the context of the original Strain groups based on the original methods of distinguishing Strains (i.e., tobacco and potato assays involving use of 'differential' potato cultivars). Additionally, sequence characterization of the complete genomes of isolates is highly recommended. However, it is acceptable to amend the names of PVY isolates with additional, specific codes to show that the isolate differs at the molecular, serological or phenotypic level from the typical Strains within a Strain group. The new isolates should preferably not be named using geographical, cultivar, or place-association designations. Since many new variants of PVY are being discovered, any new static classification system will be meaningless for the time being. A more systematic investigation and characterization of PVY from potato at the biological and molecular levels should eventually result in a biologically meaningful Genetic Strain concept.
John R. Roche - One of the best experts on this subject based on the ideXlab platform.
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Genetic Strain and diet effects on grazing behavior, pasture intake, and milk production
Journal of dairy science, 2011Co-Authors: A.j. Sheahan, E.s. Kolver, John R. RocheAbstract:Understanding how dairy cows adjust their grazing behavior in response to feed supplements is important for the development of management strategies that optimize profit from supplementation. New Zealand Holstein-Friesian (HF) cows have been selected for milk production on a predominantly pasture-based diet; in comparison, HF cows of North American (NA) ancestry have been selected almost exclusively for milk yield and fed diets high in nonfiber carbohydrates (NFC). We hypothesized, therefore, that supplementation would have differing effects on grazing behavior, pasture dry matter intake (DMI), and milk production in these Genetic Strains at peak, mid, and late lactation. A study was conducted over 2 consecutive lactations, with NA and NZ cows randomly allocated at calving to 0, 3, or 6 kg of dry matter/day concentrate plus unrestricted access to pasture. Pasture DMI, milk production, and grazing behavior were recorded at peak, mid, and late lactation. Concentrates were fed in equal amounts at morning and afternoon milking. The NA cows produced more milk and milk components, and had a greater pasture DMI, despite spending less time grazing. Declines in time spent grazing and pasture DMI were associated with increasing concentrate DMI. Grazing behavior following morning supplementation was different from that recorded following afternoon supplementation. Grazing ceased following morning supplementation before rumen fill could be a limiting factor, and the length of the grazing interval was inversely proportional to the amount of concentrate offered; these results suggest that physiological rather than physical stimuli were responsible for grazing cessation. The decrease in time spent grazing with increasing concentrate DMI is consistent with changes in neuroendocrine factors secreted in response to the presence of food in the digestive tract or with circulating products of digestion. After afternoon supplementation, sunset signaled the end of grazing irrespective of stage of lactation, timing of sunset, or supplementation status, suggesting that photoperiod influenced grazing behavior. Results confirmed changes in grazing behavior, an associated reduction in pasture DMI, and an increase in milk production when cows consume increasing amounts of concentrates. However, as the effect of supplement on grazing behavior differed between morning and afternoon supplementation, further research is required to better understand the factors controlling grazing behavior, to allow improved milk production responses to supplementary feeding.
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Genetic Strain and reproductive status affect endometrial fatty acid concentrations
Journal of dairy science, 2009Co-Authors: Susanne Meier, A. J. Peterson, Murray D. Mitchell, Mathew D. Littlejohn, Caroline G. Walker, John R. RocheAbstract:Poor reproductive performance limits cow longevity in seasonal, pasture-based dairy systems. Few differences in ovarian dynamics have been reported in different Strains of Holstein-Friesian cows, implying that the uterine environment may be a key component determining reproductive success. To test the hypothesis that the uterine environment differs among Genetic Strains of the Holstein-Friesian cow, endometrial fatty acids (FA) were analyzed from New Zealand (NZ), and North American (NA) Holstein-Friesian cows. The effect of reproductive status was also investigated, with cows from both Holstein-Friesian Strains slaughtered on either d 17 of the estrous cycle (termed cyclic) or d 17 of pregnancy (after embryo transfer; termed pregnant). Endometrial tissues were collected from 22 cows (NZ pregnant, n = 6; NZ cyclic, n = 4; NA pregnant, n = 6; NA cyclic, n = 6), and FA composition was analyzed. Daily plasma progesterone concentrations, milk production, milk FA composition, body weight, and body condition score were determined. Milk yield (4% fat-corrected milk) was similar for the NZ (28.5 kg/d) and NA (29.3 kg/d; SE 2.07 kg/d) cows, but NZ cows had a greater mean milk fat percentage. Mean plasma progesterone concentrations were significantly greater in NZ cows. Plasma progesterone concentrations were similar in the pregnant and cyclic groups. Mean length of the trophoblast recovered from the pregnant cows (NZ: 20.8 +/- 2.84 cm; NA: 27.9 +/- 10.23 cm) was not affected by Genetic Strain. Endometrial tissues from NZ cows contained greater concentrations of C17:0, C20:3n-3, and total polyunsaturated FA. The endometria from pregnant cows contained greater concentrations of C17:0, C20:2, and C20:3n-6, and less C20:1, C20:2, C20:5n-3. The observed changes in endometrial FA between Holstein-Friesian cows of different Genetic origins or reproductive states may reflect differences in endometrial function and may affect reproductive function.