| Project/Area Number |
09556011
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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 |
蚕糸・昆虫利用学
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| Research Institution | YAMAGATA UNIVERSITY |
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Principal Investigator |
GOTO Michiyo Agriculture, Yamagata University, Associate Professor, 農学部, 助教授 (10007081)
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| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Koichi Agriculture, Iwate University, Professor, 農学部, 教授 (20003791)
IGARASHI Kiharu Agriculture, Yamagata University, Associate Professor, 農学部, 教授 (00111336)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,200,000 (Direct Cost: ¥13,200,000)
Fiscal Year 1999: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1998: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1997: ¥11,500,000 (Direct Cost: ¥11,500,000)
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| Keywords | Ostrinia furnacalis / Enosima leucotaeniella / Mamestra brassicae / Cold Hardiness / Winter Diapause / Winter Post-diapause / Summer Diapause / Summer Post-diapause / トレハロース / 蛹 / アワノメイガ(Ostrinia furnacalis) / 越冬幼虫 / 休眠 / 無酸素条件 / グリセロール / アラニン / 馴化温度 / 休眠覚醒 / 訓化温度 / ヒエホソメイガ Enosima leucotaeniella |
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| Research Abstract |
Cold hardiness and diapause are both essential components of winter survival for most insects of the temperate zone, but in many case, it is not clear how these two are related. Overwintering larvae in Enosima leucotaeniella terminate diapause in November, before winter, but trehalose content peaked in January. To know the factors, amounts of several metabolites were measured in overwintering larvae acclimated to temperatures between -5 and 15℃ for 30 days. Alanine levels rose at low temperature only when the larvae were in the diapausing stage. The levels of the trehalose rose at low temperature in both the diapausing and post-diapausing stags, although it was higher at aerobic conditions in the post-diapausing stage. These results suggest that efficient trehalose synthesis occurs under the combination of low temperature and aerobic conditions of the post-diapausing stage, so that cold hardiness in this insect larvae may rise to a high level in winter.
Diapause in overwintering larvae
… More
of Ostrinia furnacalis, terminated between November and December, but cold hardiness and glycerol content increased from November to January. Cold hardiness was strongly correlated with glycerol content. High levels of alanine accumulated under anaerobic conditions which suggesting that alanine do not influence on cold hardiness. These results suggest that O. furnacalis has a highly developed cold hardiness mechanism which includes termination of diapause before winter and an accumulation of high levels of glycerol in the post diapause.
To elucidate the relationship between summer and winter diapause and post-summer and post-winter diapause in Mamestra brassicae, the levels of various substances and cold hardiness were measured in diapausing and post-diapausing overwintering pupae. Pupae were incubated and acclimated temperature, and gradually transferred into low temperatures after one week incubation. Trehalose content and cold hardiness in both the summer and winter diapausing pupae were almost same levels under low temperatures from 5℃ to -10℃, but were quite different between post-winter and post-summer diapause. These results suggest that cold hardiness mechanism is unique one which is only found in the post winter diapause. Less
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