Ultraviolet radiation tolerance in hydrated and desiccated eutardigrades
Ultraviolet radiation tolerance in hydrated and desiccated eutardigrades
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DOI：
10.1111/j.1439-0469.2010.00607.x
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发表时间：
2011-05-01
影响因子：
1.9
通讯作者：
Rebecchi, Lorena
中科院分区：
文献类型：
--
作者：
Altiero, Tiziana;Guidetti, Roberto;Rebecchi, Lorena
迄今为止，大多数关于缓步动物对极端胁迫的抗性研究都集中在它们对几种化学和物理极端的反应上，但关于缓步动物对紫外线辐射的反应的数据仍然缺乏。考虑到太空飞行提供的未来前景，我们比较了两种半水降解物种（richterparamacrobious和Ramazzottius oberhaeuseri）在两种不同生理条件（干燥和水合状态）下对紫外线照射的生物反应，单独或联合多种应激源（温度和空气相对湿度）。在一个受控的气候室中，将缓步动物暴露于7种不同的紫外线剂量（从10.32到87.72 kJ -2）。结果表明，活性和无水缓步动物能够承受高剂量的紫外线辐射。水合和干燥标本的存活率与紫外线剂量呈负相关，李氏杆菌对紫外线剂量的耐受性优于奥伯海氏杆菌。令人惊讶的是，对物理和化学极端应力的耐受性并不是干燥缓步动物的专有特性；在某些环境条件下（空气湿度高或温度低），干燥的水熊虫承受紫外线照射的能力比水合的水熊虫低或相似。这进一步证明了这一动物群体在忍受极端压力方面的独特性。此外，我们证明了高温对水熊虫在水合和干燥动物的紫外线暴露期间的生存有很强的影响。
So far, most studies on tardigrade resistance to extreme stresses have focused on their responses to several chemical and physical extremes, but there is still a paucity of data regarding the tardigrade responses to ultraviolet radiation. Considering also the future perspectives offered by space flights, we compared the biological responses of two eutardigrade species (Paramacrobiotus richtersi and Ramazzottius oberhaeuseri) to UV irradiation, alone or in combination with multiple stressors (temperature and air relative humidity) in two different physiological conditions (desiccated and hydrated states). Tardigrades were exposed to seven different UV doses (from 10.32 up to 87.72 kJ m-2) in a controlled climatic chamber. The results showed that active and anhydrobiotic tardigrades were able to withstand high doses of ultraviolet radiations. The survival rate of hydrated or desiccated specimens of both species was inversely related to the UV doses, with P. richtersi that better tolerated the increase of UV dose than R. oberhaeuseri. Surprisingly, the tolerance to physical and chemical extreme stresses is not an exclusive property of desiccated tardigrades; in certain environmental conditions (high air humidity level or low temperature), desiccated tardigrades have a lower or similar ability to withstand UV irradiation than hydrated ones. This represents a further demonstration of the uniqueness of this animal group in tolerating extreme stresses. In addition, we demonstrated that high temperatures have a strong impact on tardigrade survival during UV exposition both in hydrated and desiccated animals.