Establishment of a rearing system of the extremotolerant tardigrade Ramazzottius varieornatus:: A new model animal for astrobiology
Establishment of a rearing system of the extremotolerant tardigrade Ramazzottius varieornatus:: A new model animal for astrobiology
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DOI：
10.1089/ast.2007.0139
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发表时间：
2008-06-01
期刊：
影响因子：
4.2
通讯作者：
Okuda, Takashi
中科院分区：
文献类型：
--
作者：
Horikawa, Daiki D.;Kunieda, Takekazu;Okuda, Takashi
与极端环境中的单细胞微生物相比，对多细胞生物耐受特定极端环境的能力的研究相对较少。缓步动物是极端耐受性动物，可以进入称为脱水共生的无代谢干燥状态，并对各种极端环境条件具有高耐受性，特别是在脱水共生中。虽然缓步动物已被预期是一个潜在的模式动物的天体生物学研究，由于其出色的脱水和极端耐受能力，很少有研究与养殖缓步动物的耐受性已被报道，可能是由于缺乏一个模式物种，可以很容易地保持在饲养条件下。本文报道了以绿色小球藻为饵料成功地培育出食草性缓步动物Ramazzottius varieornatus。寿命为35 ± 16.4 d，产卵需要5.7 ± 1.1 d孵化，动物在孵化后9 d开始存款卵。该物种的饲养个体在卵、幼鱼和成虫阶段的整个生命周期中都具有脱水能力。此外，在脱水状态下饲养的成年人耐受90摄氏度和-196摄氏度的温度，暴露于99.8%的乙腈或照射与4000戈伊He-4离子。根据它们的生活史特征和对极端逆境的耐受性，R. varieornatus可能是多细胞生物天体生物学研究的合适模型。
Studies on the ability of multicellular organisms to tolerate specific environmental extremes are relatively rare compared to those of unicellular microorganisms in extreme environments. Tardigrades are extremotolerant animals that can enter an ametabolic dry state called anhydrobiosis and have high tolerance to a variety of extreme environmental conditions, particularly while in anhydrobiosis. Although tardigrades have been expected to be a potential model animal for astrobiological studies due to their excellent anhydrobiotic and extremotolerant abilities, few studies of tolerance with cultured tardigrades have been reported, possibly due to the absence of a model species that can be easily maintained under rearing conditions. We report the successful rearing of the herbivorous tardigrade, Ramazzottius varieornatus, by supplying the green alga Chlorella vulgaris as food. The life span was 35 +/- 16.4 d, deposited eggs required 5.7 +/- 1.1 d to hatch, and animals began to deposit eggs 9 d after hatching. The reared individuals of this species had an anhydrobiotic capacity throughout their life cycle in egg, juvenile, and adult stages. Furthermore, the reared adults in an anhydrobiotic state were tolerant of temperatures of 90 degrees C and - 196 degrees C, and exposure to 99.8% acetonitrile or irradiation with 4000 Gy He-4 ions. Based on their life history traits and tolerance to extreme stresses, R. varieornatus may be a suitable model for astrobiological studies of multicellular organisms.