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【科普】天然抗冻 －－ 节肢动物如何过冬？
Public release date: 2-Apr-2007
Natural anti-freeze -- how arthropods survive the cold
Given the choice, many of us would opt for warmer climes during the bleak midwinter. However, most of us cannot afford to move abroad for a few months, so instead we pile on extra layers of clothing to keep warm. Arthropods face much the same dilemma, as they cannot migrate long distances to avoid low winter temperatures ?so why are they not killed off by the cold? Dr Melody Clark, from the British Antarctic Survey, will present data on the fascinating ways two species of these animals combat the cold on Tuesday 3rd April at the Society for Experimental Biology抯 Annual Meeting in Glasgow.
Onychiurus arcticus (from the Arctic) uses protective dehydration to survive harsh Arctic winters. This means that water is lost from the body across a diffusion gradient between the animals?super-cooled body fluids and ice in the surroundings. "During this process the body loses all its water and you end up with a normal looking head, and a body which looks like a crumpled up crisp packet when it is fully dehydrated. But add a drop of water and it all goes back to normal!" explains Dr Clark. Scientists examined the different stages of this process to see which genes were activated.
Cryptopygus antarcticus lives in the Antarctic and uses a different mechanism to survive cold temperatures. These creatures accumulate anti-freeze compounds which lower the temperature at which their bodies freeze, meaning they can withstand temperatures as low as minus 30癈. Within this population there is a clear divide into less- and more-cold hardened animals, which has been a puzzle to researchers. However, by looking for differences in gene expression levels between the two populations, scientists think that there could be a link to moulting (this is the process by which arthropods shed their exoskelton).
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Upper panel shows Onychiurus arcticus. The effect of protective dehydration is shown in the lower panel.
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screen.width-333)this.width=screen.width-333" width=200 height=280 title="Click to view full 3639_rel.jpg (200 X 280)" border=0 align=absmiddle> 本人已认领该文编译，48小时后若未提交译文，请其他战友自由认领。 Natural anti-freeze -- how arthropods survive the cold
天然抗冻 －－ 节肢动物如何过冬？
Given the choice, many of us would opt for warmer climes during the bleak midwinter. However, most of us cannot afford to move abroad for a few months, so instead we pile on extra layers of clothing to keep warm. Arthropods face much the same dilemma, as they cannot migrate long distances to avoid low winter temperatures，so why are they not killed off by the cold? Dr Melody Clark, from the British Antarctic Survey, will present data on the fascinating ways two species of these animals combat the cold on Tuesday 3rd April at the Society for Experimental Biology Annual Meeting in Glasgow.
如有可能，我们中的大多数都愿意到气候宜人的地方去过冬。但是，并不是人人都有钱到国外去待几个月的，很多人只能裹着一层又一层衣服来抵挡严寒。节肢动物也同样遇到这样的麻烦，因为它们也不能长距离的迁移以逃避寒冬，但是为什么它们没被冻死呢？在4月3号格拉斯哥举行的试验生物学协会的年会上，来自英国南极观察站的Melody Clark博士向人们展示两种节肢动物如何神奇的度过寒冬。
Onychiurus arcticus (from the Arctic) uses protective dehydration to survive harsh Arctic winters. This means that water is lost from the body across a diffusion gradient between the animals super-cooled body fluids and ice in the surroundings. "During this process the body loses all its water and you end up with a normal looking head, and a body which looks like a crumpled up crisp packet when it is fully dehydrated. But add a drop of water and it all goes back to normal!" explains Dr Clark. Scientists examined the different stages of this process to see which genes were activated.
首先登场的是北极棘跳虫（Onychiurus sibiricus ，Tullberg），为了在凌厉的北极冬天中生存下来，它会使自己完全脱水。这意味着这个小虫的体温将会达到冰点以下，而与周围的冰雪形成一个蒸发梯度，水分就通过这个方式挥发掉了。Clark博士兴奋的解释到：“在这个过程中，虫子体内所有的水分都失去后，你将会看到它的头部还算正常，而身体看起来像一个褶皱的口袋。但是只要有一滴水，它又完全恢复了！”科学家们研究了整个过程的不同阶段以期找出是什么基因在发挥作用。
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作者:admin@医学,生命科学 2011-08-14 05:12
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