Radiation tolerance in the tardigrade Milnesium tardigradum
Radiation tolerance in the tardigrade Milnesium tardigradum
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DOI：
10.1080/09553000600972956
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发表时间：
2006-12-01
影响因子：
2.6
通讯作者：
Kuwabara, Mikinori
中科院分区：
文献类型：
--
作者：
Horikawa, Daiki D.;Sakashita, Tetsuya;Kuwabara, Mikinori
目的：已知迟滞可在高剂量电离辐射下存活。然而，在培养条件下迟滞病毒的辐射效应尚未见报道。在这项研究中，我们通过测定辐射后的短期和长期存活率以及繁殖能力来研究迟发性迟缓虫对伽马射线和重离子的耐受性。材料和方法：水生和无水生物动物分别接受伽马射线(1000-7000GY)或重离子(1000-8000GY)照射，以评估照射后2、24和48h的短期存活率。结果：照射后48h，水生动物的半数致死剂量分别为5000Gy射线和6200Gy重离子，厌水生物动物的半数致死剂量分别为4400Gy射线和5200Gy.无论是水合生物组还是无水生物组，伽马辐射都以剂量依赖的方式缩短了平均寿命。受照动物均未产卵，但经2000Gy射线照射的水合动物产下3枚卵而未孵化，而未受照的受照动物产卵成功孵化。结论：迟滞分枝杆菌在高剂量电离辐射下均能存活，但1000Gy射线照射可使其不育。
Purpose: Tardigrades are known to survive high doses of ionizing radiation. However, there have been no reports about radiation effects in tardigrades under culture conditions. In this study, we investigated tolerance of the tardigrade, Milnesium tardigradum, against gamma-rays and heavy ions by determining short-term or long-term survival, and reproductive ability after irradiation.Materials and methods: Hydrated and anhydrobiotic animals were exposed to gamma-rays (1000-7000 Gy) or heavy ions (1000-8000 Gy) to evaluate short-term survival at 2, 24 and 48 h post-irradiation. Long-term survival and reproduction were observed up to 31 days after irradiation with gamma-rays (1000-4000 Gy).Results: At 48 h after irradiation, median lethal doses were 5000 Gy (gamma-rays) and 6200 Gy (heavy ions) in hydrated animals, and 4400 Gy (gamma-rays) and 5200 Gy (heavy ions) in anhydrobiotic ones. Gamma-irradiation shortened average life span in a dose-dependent manner both in hydrated and anhydrobiotic groups. No irradiated animals laid eggs with one exception in which a hydrated animal irradiated with 2000 Gy of gamma-rays laid 3 eggs, and those eggs failed to hatch, whereas eggs produced by non-irradiated animals hatched successfully.Conclusion: M. tardigradum survives high doses of ionizing radiation in both hydrated and anhydrobiotic states, but irradiation with > 1000 Gy makes them sterile.