PHYSIOLOGICAL AND CYTO-METRICAL STUDIES ON SPERMATOGENESIS OF SILKWORMS

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 06454066
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 蚕糸・昆虫利用学
• Research Institution: SHINSHU UNIVERSITY
• Principal Investigator: NAKAGAKI Masao SHINSU UNIVERSITY,TEXTILE SCIENCE AND TECHNOLOGY,ASSOCIATE PROFESSOR, 繊維学部, 助教授 (70135169)
• Project Period (FY): 1994 – 1996
• Keywords: Bombyx mori / trimolter larvae / JH / ecdysteroid / sperm cell / flow cytometry

Research Abstract

The purpose of the present studies was to investigate the effects of endocrine treatment on the timing of the appearance of sperm cells in ressesive trimolter silkworm. The timing was determined by the oneset of formation of the haploid cells (1C cells) using DNA flow cytometry. The treatments with juvenile hormone and KK-42 (1-benzyl-5-[(E)-2,6-dimethyl-1,5-heptadienyl] imidazole) were done at low doses that did not affect the number of larval molt. In the testis of untreated ressesive trimolter, 1C cells were formed on day 4 of 4th inster. Treatment with juvenile hormone caused a delay of 2 days in the oneset of formation of 1C cells. In contrast, KK-42 treatment hastened the appearance of 1C cells. The oneset of 1C-cell appearance changed from day 4 to day 0 of 4th instar by this treatment. High dose of ecdysteroid that caused the supernumerary (4th) larval molt had a few delay in the oneset of formation of 1C cells in ressesive trimolter. On the other hand, ecdysteroid treatment on dominant trimolter at same dose as on ressesive trimolter did not cause the supernumerary (4th) larval molt, but delayd the appearance of 1C cells for one day. These results suggest that juvenile hormone and ecdysteroid may involve a process from spermatocyte to sperm cell in ressesive trimolter.