期刊
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
卷 103, 期 38, 页码 14223-14227出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0606840103
关键词
Antarctica; cold tolerance; protein aggregation; temperature stress; thermotolerance
Antarctica's terrestrial environment is a challenge to which very few animals have adapted. The largest, free-living animal to inhabit the continent year-round is a flightless midge, Belgica antarctica. Larval midges survive the lengthy austral winter encased in ice, and when the ice melts in summer, the larvae complete their 2-yr life cycle, and the wingless adults form mating aggregations while subjected to surprisingly high substrate temperatures. Here we report a dichotomy in survival strategies exploited by this insect at different stages of its life cycle. Larvae constitutively up-regulate their heat shock proteins (small hsp, hsp70, and hsp90) and maintain a high inherent tolerance to temperature stress. High or low temperature exposure does not further up-regulate these genes nor does it further enhance thermotolerance. Such preemptive synthesis of hsps is sufficient to prevent irreversible protein aggregation in response to a variety of common environmental stresses. Conversely, adults exhibit no constitutive up-regulation of their hsps and have a lower intrinsic tolerance to high temperatures, but their hsps can be thermally activated, resulting in enhanced thermotolerance. Thus, the midge larvae, but not the adults, have adopted the unusual strategy of expressing hsps continuously, possibly to facilitate proper protein folding in a cold habitat that is more thermally stable than that of the adults but a habitat subjected frequently to freeze-thaw episodes and bouts of pH, anoxic, and osmotic stress.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据