| Project/Area Number |
18390131
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Parasitology (including Sanitary zoology)
|
|---|
| Research Institution | Osaka University |
|---|
Principal Investigator |
TANABE Kazuyuki Osaka University, Research Instikne for Itrobial Diseass, SA Professor (40047410)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
HASHIMOTO Tetsuo Tsukuba University, Institute of Biological Sciences, Professor (50208451)
SAWAI Hiromi Osaka University, Research Institute for Microbial Diseases, Designated Researcher (60377124)
|
|---|
| Project Period (FY) |
2006 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥16,510,000 (Direct Cost: ¥14,800,000、Indirect Cost: ¥1,710,000)
Fiscal Year 2007: ¥7,410,000 (Direct Cost: ¥5,700,000、Indirect Cost: ¥1,710,000)
Fiscal Year 2006: ¥9,100,000 (Direct Cost: ¥9,100,000)
|
|---|
| Keywords | Malaria / Antigen / Gene / Infectious disease / Evolution / Plasmodium vivax |
|---|
| Research Abstract |
1. Geographic variation in multiplicity of infection
Multiplicity of infection (MOI) was compared among P falciparum populations from diverse geographic areas. MOI as measured by PCR-based mspl- 5' haplotyping was high in Africa, whereas there was no discernible association between MOI and the intensity of malaria transmission in Melanesia. Results suggest that the acquisition of strain specific protective immunity against malaria is associated with not only the intensity of malaria transmission but also the number of genotypes prevalent in local areas and MOI.
2. Origin of and natural selection in mspl polymorphism of P. vivax
To investigate the evolutionary history of mspl polymorphism in P vivax, phylogenetic trees of mspl from P. vivax and related monkey malaria parasite species was constructed. All P vivax mspl alleles cluster in the P vivax lineage and are not distributed among other species. Similarly, all P cynomolgi mspl alleles cluster in the P cynomolgi lineage. This suggests that the origin of P. vivax mspl polymorphism is relatively recent. We observed positive selection_in the P vivax lineage but not in P cynomolgi. This study shows that the evolutionary history of mspl differs greatly among parasite lineages.
3. Phylogeny of the cytosolic SSUrRNA of Plasmodium spp.
To infer the SSUrRNA phylogeny of the genus Plasmodium, sequences of genes encoding paralogous copies of the cyto-SSUrRNA, A-type-like and S-type-like genes, from eight simian Plasmodium species were obtained. The maximum likelihood analyses of these sequences, together with all cyto-SSUrRNA sequences currently available in the database, clearly demonstrated four independent clades in the unrooted Plasmodium tree: a simian Plasmodium + P vivax clade, a rodent Plasmodium clade (P. berghei/P. yoelii), a large clade including P malariae, P. falciparum, P reichnowi, and avian and reptilian Plasmodium species, and a P ovale clade.
|
