The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
Ian Beveridge - One of the best experts on this subject based on the ideXlab platform.
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a comparison of the first internal transcribed spacer of ribosomal dna in seven species of Trichostrongylus nematoda trichostrongylidae
International Journal for Parasitology, 1998Co-Authors: H Hoste, Neil B Chilton, Ian Beveridge, Robin B GasserAbstract:Abstract The first internal transcribed spacer (ITS-1) of the ribosomal DNA of seven species of Trichostrongylus was sequenced. The length of ITS-1 in the different species varied from 387 to 390 bases. The G+C content of the ITS-1 sequences were approximately 42%. Little or no intraspecific variation was detected in the three species, Trichostrongylus axei, Trichostrongylus colubriformis and Trichostrongylus vitrinus, for which multiple isolates from different geographical regions were sequenced. In contrast, the level of ITS-1 sequence differences between species ranged from 1.3% to 5.7%. The greatest sequence differences were detected between T. tenuis, the parasite species which infects birds and the six species found in mammals. Some of the nucleotide differences occurred at sites corresponding to recognition sites for restriction endonucleases. These results are compared with previous data obtained for the second internal transcribed spacer (ITS-2). The ITS-1 data indicate that this region of rDNA may also be useful for systematic studies in trichostrongylid nematodes.
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Abnormal spicule development in a laboratory strain of Trichostrongylus vitrinus
Journal of Helminthology, 1997Co-Authors: Ian BeveridgeAbstract:The occurrence of specimens in a laboratory strain of Trichostrongylus vitrinus exhibiting unusual spicules resembling those of T. minor and T. angistris is reported and the abnormal spicules described. The specimens include individuals with one spicule typical of T. vitrinus and the other spicule of the abnormal type. Possible reasons for the occurrence of such abnormalities are discussed.
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differences in the second internal transcribed spacer ribosomal dna between five species of Trichostrongylus nematoda trichostrongylidae
International Journal for Parasitology, 1995Co-Authors: H Hoste, Neil B Chilton, Robin B Gasser, Ian BeveridgeAbstract:Abstract The second internal transcribed spacer (ITS-2) of the ribosomal DNA of 5 species of Trichostrongylus has been sequenced. The ITS-2 of the 5 species was 237 or 238 bases in length, and had a GC content of approximately 30%. No evidence of intraspecific variation was detected in the ITS-2 sequence of T. colubriformis, T. vitrinus or T. retortaeformis, irrespective of the life cycle stage examined. There was evidence, however, of variation at five positions in the ITS-2 sequence of T. vitrinus samples and at one position in T. axei, indicating intra-individual variation in the sequence of different copies of the ribosomal DNA. Nonetheless, there were consistent sequence differences between the five Trichostrongylus species examined. The level of interspecific differences in nucleotide sequence was low (1.3–7.6%), with the species infecting birds (T. tenuis) being genetically more different to the four species found in mammals. Some of the nucleotide differences between species occurred at the recognition sites of endonucleases, which makes them of important diagnostic value for species identification. Also of significance are the recognition sites for several enzymes located within the regions of sequence homology for the five species of Trichostrongylus. These may prove useful in distinguishing between genera of trichotrongyle nematodes.
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lack of intraspecific variation in the second internal transcribed spacer its 2 of Trichostrongylus colubriformis ribosomal dna
International Journal for Parasitology, 1993Co-Authors: H Hoste, Neil B Chilton, Robin B Gasser, S Mallet, Ian BeveridgeAbstract:Abstract The nucleotide sequence of the second internal transcribed spacer (ITS-2) was determined for three populations of the parasitic nematode Trichostrongylus colubriformis which differed in their susceptibility to benzimidazole anthelmintics and/or in their geographical origin. No intraspecific variation was found in the ITS-2 sequence, indicating that this region of rDNA is inadequate to discriminate between resistant and susceptible populations of T. colubriformis , but it may prove useful for distinguishing between species of Trichostrongylus .
Peter J Hudson - One of the best experts on this subject based on the ideXlab platform.
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regulation and stability of a free living host parasite system Trichostrongylus tenuis in red grouse i monitoring and parasite reduction experiments
Journal of Animal Ecology, 1992Co-Authors: Peter J Hudson, David Newborn, Andrew P DobsonAbstract:Intensive population studies were conducted for 10 years on red grouse (Lagopus lagopus scoticus) and the parasitic nematode, Trichostrongylus tenuis, in northern England. Winter loss was the key factor determining changes in grouse numbers, although breeding losses were also important. T. tenuis had an aggregated distribution within the adult grouse population, even though the degree of aggregation was relatively low compared with other parasite systems
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regulation and stability of a free living host parasite system Trichostrongylus tenuis in red grouse ii population models
Journal of Animal Ecology, 1992Co-Authors: Andrew P Dobson, Peter J HudsonAbstract:The population dynamics of red grouse, Lagopus lagopus scoticus and the parasitic nematode, Trichostrongylus tenuis were explored to determine whether interactions between the parasite and host were sufficient to generate cycles in grouse abundance. Two alternative models were used that explicitly consider the dynamics of either the free-living, or arrested larval stages of the parasite. Providing that the life expectancy of the free-living larvae is more than 2-4 weeks, the parasite can readily establish in gousse populations
Andrew P Dobson - One of the best experts on this subject based on the ideXlab platform.
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regulation and stability of a free living host parasite system Trichostrongylus tenuis in red grouse i monitoring and parasite reduction experiments
Journal of Animal Ecology, 1992Co-Authors: Peter J Hudson, David Newborn, Andrew P DobsonAbstract:Intensive population studies were conducted for 10 years on red grouse (Lagopus lagopus scoticus) and the parasitic nematode, Trichostrongylus tenuis, in northern England. Winter loss was the key factor determining changes in grouse numbers, although breeding losses were also important. T. tenuis had an aggregated distribution within the adult grouse population, even though the degree of aggregation was relatively low compared with other parasite systems
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regulation and stability of a free living host parasite system Trichostrongylus tenuis in red grouse ii population models
Journal of Animal Ecology, 1992Co-Authors: Andrew P Dobson, Peter J HudsonAbstract:The population dynamics of red grouse, Lagopus lagopus scoticus and the parasitic nematode, Trichostrongylus tenuis were explored to determine whether interactions between the parasite and host were sufficient to generate cycles in grouse abundance. Two alternative models were used that explicitly consider the dynamics of either the free-living, or arrested larval stages of the parasite. Providing that the life expectancy of the free-living larvae is more than 2-4 weeks, the parasite can readily establish in gousse populations
Robin B Gasser - One of the best experts on this subject based on the ideXlab platform.
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in silico analysis of expressed sequence tags from Trichostrongylus vitrinus nematoda comparison of the automated estexplorer workflow platform with conventional database searches
International Conference on Bioinformatics, 2008Co-Authors: Shivashankar H Nagaraj, Robin B Gasser, Alasdair J Nisbet, Shoba RanganathanAbstract:Background The analysis of expressed sequence tags (EST) offers a rapid and cost effective approach to elucidate the transcriptome of an organism, but requires several computational methods for assembly and annotation. Researchers frequently analyse each step manually, which is laborious and time consuming. We have recently developed ESTExplorer, a semi-automated computational workflow system, in order to achieve the rapid analysis of EST datasets. In this study, we evaluated EST data analysis for the parasitic nematode Trichostrongylus vitrinus (order Strongylida) using ESTExplorer, compared with database matching alone.
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a comparison of the first internal transcribed spacer of ribosomal dna in seven species of Trichostrongylus nematoda trichostrongylidae
International Journal for Parasitology, 1998Co-Authors: H Hoste, Neil B Chilton, Ian Beveridge, Robin B GasserAbstract:Abstract The first internal transcribed spacer (ITS-1) of the ribosomal DNA of seven species of Trichostrongylus was sequenced. The length of ITS-1 in the different species varied from 387 to 390 bases. The G+C content of the ITS-1 sequences were approximately 42%. Little or no intraspecific variation was detected in the three species, Trichostrongylus axei, Trichostrongylus colubriformis and Trichostrongylus vitrinus, for which multiple isolates from different geographical regions were sequenced. In contrast, the level of ITS-1 sequence differences between species ranged from 1.3% to 5.7%. The greatest sequence differences were detected between T. tenuis, the parasite species which infects birds and the six species found in mammals. Some of the nucleotide differences occurred at sites corresponding to recognition sites for restriction endonucleases. These results are compared with previous data obtained for the second internal transcribed spacer (ITS-2). The ITS-1 data indicate that this region of rDNA may also be useful for systematic studies in trichostrongylid nematodes.
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differences in the second internal transcribed spacer ribosomal dna between five species of Trichostrongylus nematoda trichostrongylidae
International Journal for Parasitology, 1995Co-Authors: H Hoste, Neil B Chilton, Robin B Gasser, Ian BeveridgeAbstract:Abstract The second internal transcribed spacer (ITS-2) of the ribosomal DNA of 5 species of Trichostrongylus has been sequenced. The ITS-2 of the 5 species was 237 or 238 bases in length, and had a GC content of approximately 30%. No evidence of intraspecific variation was detected in the ITS-2 sequence of T. colubriformis, T. vitrinus or T. retortaeformis, irrespective of the life cycle stage examined. There was evidence, however, of variation at five positions in the ITS-2 sequence of T. vitrinus samples and at one position in T. axei, indicating intra-individual variation in the sequence of different copies of the ribosomal DNA. Nonetheless, there were consistent sequence differences between the five Trichostrongylus species examined. The level of interspecific differences in nucleotide sequence was low (1.3–7.6%), with the species infecting birds (T. tenuis) being genetically more different to the four species found in mammals. Some of the nucleotide differences between species occurred at the recognition sites of endonucleases, which makes them of important diagnostic value for species identification. Also of significance are the recognition sites for several enzymes located within the regions of sequence homology for the five species of Trichostrongylus. These may prove useful in distinguishing between genera of trichotrongyle nematodes.
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lack of intraspecific variation in the second internal transcribed spacer its 2 of Trichostrongylus colubriformis ribosomal dna
International Journal for Parasitology, 1993Co-Authors: H Hoste, Neil B Chilton, Robin B Gasser, S Mallet, Ian BeveridgeAbstract:Abstract The nucleotide sequence of the second internal transcribed spacer (ITS-2) was determined for three populations of the parasitic nematode Trichostrongylus colubriformis which differed in their susceptibility to benzimidazole anthelmintics and/or in their geographical origin. No intraspecific variation was found in the ITS-2 sequence, indicating that this region of rDNA is inadequate to discriminate between resistant and susceptible populations of T. colubriformis , but it may prove useful for distinguishing between species of Trichostrongylus .
Lukas F Keller - One of the best experts on this subject based on the ideXlab platform.
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bayesian paternity analysis and mating patterns in a parasitic nematode Trichostrongylus tenuis
Heredity, 2010Co-Authors: Paul C D Johnson, Jarrod D Hadfield, Lucy M I Webster, Aileen Adam, Barbara K Mable, Lukas F KellerAbstract:Bayesian paternity analysis and mating patterns in a parasitic nematode, Trichostrongylus tenuis
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abundant variation in microsatellites of the parasitic nematode Trichostrongylus tenuis and linkage to a tandem repeat
Molecular and Biochemical Parasitology, 2006Co-Authors: Paul C D Johnson, Lucy M I Webster, Aileen Adam, Lukas F Keller, Robert J Buckland, Deborah A DawsonAbstract:An understanding of how genes move between and within populations of parasitic nematodes is important in combating the evolution and spread of anthelmintic resistance. Much has been learned by studying mitochondrial DNA markers, but autosomal markers such as microsatellites have been applied to only a few nematode species, despite their many advantages for studying gene flow in eukaryotes. Here, we describe the isolation of 307 microsatellites from Trichostrongylus tenuis, an intestinal nematode of red grouse. High levels of variation were revealed at sixteen microsatellite loci (including three sex-lined loci) in 111 male T. tenuis nematodes collected from four hosts at a single grouse estate in Scotland (average He = 0.708; mean number of alleles = 12.2). A population genetic analysis detected no deviation from panmixia either between (F(ST) = 0.00) or within hosts (F(IS) = 0.015). We discuss the feasibility of developing microsatellites in parasitic nematodes and the problem of null alleles. We also describe a novel 146-bp repeat element, TteREP1, which is linked to two-thirds of the microsatellites sequenced and is associated with marker development failure. The sequence of TteREP1 is related to the TcREP-class of repeats found in several other trichostrongyloid species including Trichostrongylus colubriformis and Haemonchus contortus.
