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托福听力练习-科学美国人60秒:蚊子消化热血

2017-05-06 09:11:00来源：科学美国人60秒

点击查看>>科学美国人60秒音频：蚊子消化热血

　　科学美国人60秒听力练习：蚊子消化热血

　　科学美国人60秒英文文本

　　Mosquitoes maintain a body temperature of about 70 degrees Fahrenheit. But when a mosquito suckssome toasty warm blood, its body temperature canrocket up. It’s like developing a huge fever almostinstantly. That sudden heat can disable theirdigestive machinery. But rather than just dining off cold-blooded animals, they've evolved away to beat the heat. So says a study in the journal Proceedings of the National Academy ofSciences. [Joshua Benoit et al., "Drinking a hot blood meal elicits a protective heat shockresponse in mosquitoes"]

　　As a mosquito's body temperature rises during a warm blood meal, its guts are flooded with asubstance called heat shock protein 70. That heat shock protein acts as a sort of chaperone, keeping digestive enzymes from being curdled, and escorting any damaged ones to the wastebin. Other bloodsuckers like bedbugs produce heat shock proteins too—as do we, during afever.

　　But when researchers blocked production of that heat shock protein and let mosquitoes feast, the blood meal sat longer in their guts. Which indicates that their digestion was impaired. Andas a result they produced a quarter fewer eggs. So researchers looking to cut mosquitopopulations might try figuring out a way to make them have trouble digesting a hot meal.

　　—Christopher Intagliata

　　中文翻译请点击下一页

本文关键字: 托福听力 科学美国人60秒

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