| Project/Area Number |
15570189
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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 |
Evolutionary biology
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| Research Institution | Sophia University |
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Principal Investigator |
TAMIYA Toru Sophia University, Chemistry, Professor, 理工学部, 教授 (30119135)
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| Co-Investigator(Kenkyū-buntansha) |
KANZAWA Nobuyuki Sophia University, Chemistry, Research Associate, 理工学部, 助手 (40286761)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | snake venom / group IA phospholipase A2 / group IB phospholipase A2 / accelerated evolution / molecular evolution / Elaphe climacophora / Laticauda semifasciata / Trimersurus flavoviridis / 毒蛇 / ホスホリパーゼA2 |
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| Research Abstract |
Toxic type PLA2 (IA type) gene expressed in the venom glands and enzymic PLA2 (IB type) gene expressed in pancreas should coexist in the genome of the proteroglyphous snakes such as cobras and sea kraits. Therefore, in the genomes of proteroglyphous snakes, PLA2 genes have been evolved through discarding or maintaining the enzymic function from a common ancestor gene. The aim of this study is to clarify the evolution process of various PLA2 genes expressed in the venomous snakes.
In the academic year 2003, mRNAs were extracted from the L. semifasciata tissues, mRNAs obtained were amplified by RT-PCR. Both type PLA2s (type IB : pancreas type ; type IA : toxin type) were amplified from the heart, pancreas, venom gland, brain, lungs, and muscles. None of the deduced amino acid sequences has pro-sequences which exist in mammalian pancreatic PLA2s. Northern blot analysis and gene quantitative analysis by slot blot Southern hybridization revealed that the expression level of type IB PLA2 was very low.
In the academic year 2004, mRNAs were extracted from the livers of sea snakes (L.colubrine, L.laticaudata), habu snake (Trimeresurus flavoviridis) which has type II PLA2s in the venom and non-toxic snakes (Llaphe climacophora and Llaphe quadriviragata). cDNAs encoding type IB PLA2s were amplified from all the snakes. The size of the cDNAs are about 900 by and the deduced amino acid sequences have no pro-sequences.
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