Reduction of glycogen in eggs of the silkworm, Bombyx mori, by use of a trehalase inhibitor, trehazolin, and diapause induction in glycogen-reduced eggs.
A new trehalase inhibitor, trehazolin, caused a potent inhibition of ovary trehalase in the silkworm, Bombyx mori. A single injection of trehazolin into pupae (40&mgr;g/animal) did not interfere with the accumulation of proteins and lipids, but markedly reduced glycogen content in eggs accompanied by a remarkable increase in hemolymph trehalose levels. The most potent effect of trehazolin was expressed in eggs that developed at the mid-stage of pupal-adult development. In these eggs glycogen content was reduced to a trace level, less than 3% of that of the control. The reduced glycogen content was almost restored to the control level by injection of glucose but not by trehalose. Trehazolin treatment influenced oviposition and larval hatching, whereas embryogenesis went on normally in glycogen-reduced eggs. Injection of synthetic diapause hormone into non-diapause type hosts induced an incidence of 45% diapause in the eggs and increased their glycogen content. Surprisingly, injection of trehazolin never affected diapause induction by the hormone, despite considerably reduced glycogen content in these eggs. Thus, our findings provide a new method for production of eggs containing various amounts of glycogen, and a novel system for analyzing diapause-associated metabolism besides the well-known glycogen-sorbitol metabolism.
Katagiri
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N
Laboratory of Sericulture and Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan
Ando
O
O
Yamashita
O
O