|Budget Amount *help
¥1,800,000 (Direct Cost : ¥1,800,000)
Fiscal Year 1995 : ¥300,000 (Direct Cost : ¥300,000)
Fiscal Year 1994 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1993 : ¥800,000 (Direct Cost : ¥800,000)
Most hymenopteran insects reproduce by arrhenotoky : Fertilized eggs develop to diploid females, while unfertilized eggs develop to haploid males. Our previous results have shown that mature unfertilized eggs dissected from the ovary of the turnip sawfly, Athalia rosae (Symphyta : Hymenoptera) , can be activated simply by placing them in distillled water, and that these eggs can be fertilized by intracytoplasimic sperm injection (ICSI). The present project, conducted during 1993-1995 and supported as category C above, have resulted in publications of 5 original articles and 2 review articles. Summaries for the original articles follow :
1. cDNAs for vitellogenin were cloned. Deduced amino acid sequence showed a complete match with the 28N-terminal amino acid sequence determined. Northern blots showed that the vitellogenin gene was expressed in the female fat body as a single 6.5kb mRNA but not in the ovary.
2. Injection of fresh sperm through the anterior pole of mature unfertilized eggs
(oocytes) resulted in karyogamy (fertilization ) which developed as diploid females. Injection through the posterior pole, however, never produced fertilization but instead produced haploid-haploid chimeras.
3. Sperm frozen in liquid nitrogen without cryoprotectant were, upon thawing, non-motile and had abnormal morphology. Nevertheless, they were able to fertilize micro-injected mature oocytes which developed to fertile diploid females.
4. Previtellogenic immature ovaries transplanted into the abdomens of adult males of a closely related but different species accumulated only heterospecific yolk proteins and matured.
5. Twenty-one species (2 families, 12 genera) of sawflies (Symphyta : Hymenoptera) were examined by Western blotting using anti-Athalia rosae vitellin antisera and by Northern blotting using fragments of cloned Athalia rosae vitellogenin cDNA.Similarities in the vitellin antigenicity and the vitellogenin mRNA nucleotide sequence were noted, in contrast to a previous report to the contrary describing pyralid moth species. Less