2001 Fiscal Year Final Research Report Summary
CONTROL OF GONADAL MATURATION AND SPAWNING IN THE KURUMA PRAWN
| Project/Area Number |
10556044
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
General fisheries
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
AIDA Katsumi THEUNIVERSITYOFTOKYO, GRADUATE SCHOOL OF, AGURICUL. AND LIFE SCI., PROFESSOR, 大学院・農学生命科学研究科, 教授 (50012034)
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| Co-Investigator(Kenkyū-buntansha) |
NAGASAWA Hiromichi THEUNIVERSITYOFTOKYO, GRADUATE SCHOOL OF, AGURICUL. AND LIFE SCI., PROFESSOR, 大学院・農学生命科学研究科, 教授 (60134508)
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| Project Period (FY) |
1998 – 2000
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| Keywords | KURUMA PRAWN / GONADAL MATURATION / SPAWNING / YOLK PROTEIN / VIH / MIH / RECOMBINANT HORMONE / EYESTALK ABLATION |
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| Research Abstract |
1. Clarification of reproductive system
In this investigation, vitellogenin cDNA was firstly cloned from the ovary of the kuruma prawn, and a full length of nucleotide sequence was determined. Vitellogenin (Vg) was composed of 2587 amino acids, and it was synthesized in the follicle cells of the oocyte and hepatopancreas. Vg produced in the ovary and hepatopancreas has the same structure. After being synthesized, it was divided into 91kDa and 186kDa molecules. They were secreted into the hemolymph and incorporated into the oocytes. Changes in Vg mRNA levels following ovarian maturation under natural conditions were measured by Northern blot analysis. In the ovary, Vg mRNA was not expressed at the pre-vitellogenic stage, rapidly increased at the endogenous vitellogenic stage and decreased at the exogenous vitellogenic stage. In the hepatopancreas, Vg mRNA appeared in a small amount in the pre-vitellogneic stage, peaked in the early exogenous vitellogenic stage, and decreased. CHH secreted from the eyestalk inhibited the Vg synthesis.
2. Development of artificial method for the induction of gonadal maturation and spawning
It was confirmed that mature female prawns already having cortical rods in the oocytes could spawn within 1 day. Eyestalk ablation could induce spawning in mature female prawns not having cortical rods in the oocytes within 4 days. We have succeeded in producing recombinant CHH family peptides in E. coli and yeast. These recombinant hormones possessed biological activity, enabling future application of these hormones for artificial control of reproduction and molting.
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