| Project/Area Number |
08680793
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Developmental biology
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
YAMAMOTO Masamichi Fac.Science, Okayama Univ.Prof., 理学部, 教授 (50011565)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRAI Hiroko Fac.Science, Okayama Univ.Assoc.Prof., 理学部, 助教授 (50090478)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Plathyhelminthes / Acoela / mitochondria / genetic code / muscle / evolution / molecular phylogeny / normal table of development / 表皮 / 発生段階 / 卵割 / 細胞系譜 / 筋内 / 長足 / 分子系統 / リボソームRNA / 採卵法 / 初期発生 / 渦虫綱 |
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| Research Abstract |
1. In order to make the normal table of development in an acoel turbellarian, Convoluta naikaiensis. the process of the embryonic development was examined by scanning electron microscopy. The embryo hatched about 90 hr after fertilization and the process was divided into 16 stages.
2. In the acoel, the epidermal cells and the underlying muscle cells show a complex structure without an intervening basal structure. In order to knpw whether the muscle-epidermis complex results from degeneration, developmental process of the formation of the complex was examined by transmission electron microscopy. The complex was formed in the early stage of the embryonic development and the basal structure never appeared during the course of the muscle-epidermis complex.
Molecular phylogenetic analysis on the basis of the 18s ribosomal DNA using 9 orders of the turbellarians revealed that the Acoela is the most primitive in the turbellarian.
4. Mitochondrial codons were compared among 7 orders of the turbellarians, In the 6 orders except the Acoel, AAA and ATA code aspartic acid and isoleucine, respectively, but in the Acoel, AAA and XPA codes lysine and methionine, respectively. This fact suggests the Acoela diverged before other turbellarians were specified.
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