Tolerance of Anhydrobiotic Eggs of the Tardigrade Ramazzottius varieornatus to Extreme Environments
Tolerance of Anhydrobiotic Eggs of the Tardigrade Ramazzottius varieornatus to Extreme Environments
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DOI：
10.1089/ast.2011.0669
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发表时间：
2012-04-01
期刊：
影响因子：
4.2
通讯作者：
Kobayashi, Yasuhiko
中科院分区：
文献类型：
--
作者：
Horikawa, Daiki D.;Yamaguchi, Ayami;Kobayashi, Yasuhiko
缓步动物是微小的（长度小于1毫米）无脊椎动物，有可能生存旅行到其他星球，因为他们的耐受极端环境条件的干燥无代谢状态称为脱水。虽然已经报道了成年缓步动物对极端环境的耐受性，但很少有关于其卵耐受性的报道。我们研究了水化和脱水卵的缓步Ramazzottius varieornatus孵化后暴露于电离辐射（氦离子），极低和极高的温度，和高真空的能力。我们以前曾报道过，有一个类似的模式，对电离辐射之间的水和脱水成人的耐受性。与此相反，脱水鸡蛋（50%致死剂量; 1690戈伊）比水合鸡蛋（50%致死剂量; 509戈伊）更耐辐射。脱水鸡蛋也有更广泛的耐温性相比，水合的。超过70%的脱水蛋在-196摄氏度或+50摄氏度下成功孵化，但所有的水合蛋都未能孵化。在暴露于高真空条件（5.3 x 10（-4）Pa至6.2 x 10（-5）Pa）后，脱水生物蛋的孵化率与未处理的对照蛋相当。
Tardigrades are tiny (less than 1 mm in length) invertebrate animals that have the potential to survive travel to other planets because of their tolerance to extreme environmental conditions by means of a dry ametabolic state called anhydrobiosis. While the tolerance of adult tardigrades to extreme environments has been reported, there are few reports on the tolerance of their eggs. We examined the ability of hydrated and anhydrobiotic eggs of the tardigrade Ramazzottius varieornatus to hatch after exposure to ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. We previously reported that there was a similar pattern of tolerance against ionizing radiation between hydrated and anhydrobiotic adults. In contrast, anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at either -196 degrees C or +50 degrees C hatched successfully, but all the hydrated eggs failed to hatch. After exposure to high-vacuum conditions (5.3 x 10(-4) Pa to 6.2 x 10(-5) Pa), the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.