1998 Fiscal Year Final Research Report Summary
Molecular escape mechanisms of Theileria parasites
| Project/Area Number |
07406019
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic veterinary science/Basic zootechnical science
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| Research Institution | Hokkaido University |
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Principal Investigator |
ONUMA Misao Graduate School of Vet.Med., Hokkaido University, Professor, 大学院・獣医学研究科, 教授 (70109510)
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| Co-Investigator(Kenkyū-buntansha) |
OHASHI Kazuhiko Graduate School of Vet.Med., Hokkaido University, Inst., 大学院・獣医学研究科, 助手 (90250498)
SUGIMOTO Chihiro Graduate School of Vet.Med., Hokkaido University, Assoc.Prof., 大学院・獣医学研究科, 助教授 (90231373)
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| Project Period (FY) |
1995 – 1998
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| Keywords | Theileria parasites / piroplasm / evasion mechanism / parasite genotype / tick |
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| Research Abstract |
Theileria sergenti is a tick-borne protozoa of cattle. T.sergenti infected calves show persistent infection, possibly over their life span, but the mechanisms by which the parasites evade host defense mechanisms are not clearly understood. The complete life-cycle of T.sergenti in the mammalian host and tick vector remains unclear, the parasite may undergo a sexual stage in tick gut. To study the population changes during persistent infection in cattle and vector ticks, we have inoculated T.sergenti which consist of 2 parasite populations with C and I type allele of p32 and analyzed the population changes by allele-specific PCR to differentiate between individual types of parasites. Changes in a dominant parasite population were demonstrated during transmission from calves to the tick vector and from infected ticks to calves. The antigenic diversity which may be produced at the sexual stage in tick vector. The analysis of chromosome provide us the basic information to study the generation of genetic and antigenic polymorphism.
Chromosome analysis of T.sergenti showed 4 chromosomes. From the results of Southern blot analysis, p32 gene was located on the 1st chromosome, p23, heat shock protein 70 (HSP 70) and cystein proteinase genes were on the chromosome 2 and ribosomal RNA gene was on chromosomes 1 and 3/4.
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