| Project/Area Number |
18580051
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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 |
Applied entomology
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| Research Institution | Hamamatsu University School of Medicine |
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Principal Investigator |
YAMAHAMA Yumi Hamamatsu University School of Medicine, Faculty of Medicine, Instructor (90242784)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAKIRI Yoko Hamamatsu University School of Medicine, Technical Staff Department, Technician (20397409)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,820,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥120,000)
Fiscal Year 2007: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2006: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Keywords | Bombyx mori / egg / embryogenesis / lipid droplet / lipid staining / transmission electron microscopy / high pressure freezing and freeze substitution met / insect / 電子顕微鏡観察 |
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| Research Abstract |
Lipid droplets in insect eggs are considered one of the most important energy sources during late embryogenesis, however the process of their incorporation into the embryo is still unknown. The present study focused on the process of transition of lipid droplets from the extraembryonic yolk to the embryo of the silkworm Bombyx mori, using morphological and biochemical methods. We showed that there are three steps in the incorporation of lipid droplets from the extraembryonic yolk into the embryo ; the first step is translocation of lipid droplet directly before the blastokinesis stage, the second step is morphogenetic inclusion during dorsal closure stage, and the third step is ingestion of the extraembryonic yolk by the developing caterpillar before it's hatching. We demonstrated that lipid droplets and other component in the egg, which tended tolose by the conventional preparation method, were visible in electron microscopic observation using the high pressure freezing and freeze substitution method. We examined how the lipid droplets are incorporated into the embryonic tissues during early embryogenesis. Before blastokinesis stage, some of lipid droplets were fused and/or attached with developing rough endoplasmic reticulum, suggesting the incorporation of lipid from the cell surface and the formation of lipid droplet in the embryonic cell. After the dorsal closure stage, many yolk cells were existed in the midgut lumen, and fat bodies were in the coelom of developing caterpillar. Many lipid droplets were observed in the lumen of midgut enclosed with yolk cells, the intracellular of midgut, and the fat bodies.
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