Tsujimoto Megumu, Imura Satoshi, Kanda Hiroshi
National Institute of Polar Research (NIPR), 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan.
National Institute of Polar Research (NIPR), 10-3 Midori-cho, Tachikawa-shi, Tokyo 190-8518, Japan; SOKENDAI (The Graduate University for Advanced Studies), Tokyo, Japan.
Cryobiology. 2016 Feb;72(1):78-81. doi: 10.1016/j.cryobiol.2015.12.003. Epub 2015 Dec 25.
Long-term survival has been one of the most studied of the extraordinary physiological characteristics of cryptobiosis in micrometazoans such as nematodes, tardigrades and rotifers. In the available studies of long-term survival of micrometazoans, instances of survival have been the primary observation, and recovery conditions of animals or subsequent reproduction are generally not reported. We therefore documented recovery conditions and reproduction immediately following revival of tardigrades retrieved from a frozen moss sample collected in Antarctica in 1983 and stored at -20 °C for 30.5 years. We recorded recovery of two individuals and development of a separate egg of the Antarctic tardigrade, Acutuncus antarcticus, providing the longest records of survival for tardigrades as animals or eggs. One of the two resuscitated individuals and the hatchling successfully reproduced repeatedly after their recovery from long-term cryptobiosis. This considerable extension of the known length of long-term survival of tardigrades recorded in our study is interpreted as being associated with the minimum oxidative damage likely to have resulted from storage under stable frozen conditions. The long recovery times of the revived tardigrades observed is suggestive of the requirement for repair of damage accrued over 30 years of cryptobiosis. Further more detailed studies will improve understanding of mechanisms and conditions underlying the long-term survival of cryptobiotic organisms.
长期存活一直是对线虫、缓步动物和轮虫等微型后生动物隐生这一非凡生理特征研究最多的方面之一。在现有的微型后生动物长期存活研究中，存活实例是主要观察对象，动物的恢复情况或后续繁殖情况通常未被报道。因此，我们记录了从1983年在南极洲采集并保存在-20°C下30.5年的冷冻苔藓样本中复苏的缓步动物复苏后的恢复情况和繁殖情况。我们记录了两只南极缓步动物Acutuncus antarcticus个体的复苏以及一枚单独卵的发育情况，这提供了缓步动物作为动物或卵的最长存活记录。两只复苏个体中的一只和幼体从长期隐生状态复苏后成功多次繁殖。我们研究中记录的缓步动物已知长期存活时长的显著延长被解释为与在稳定冷冻条件下储存可能导致的最小氧化损伤有关。观察到的复苏缓步动物较长的恢复时间表明需要修复在30年隐生过程中积累的损伤。进一步更详细的研究将增进对隐生生物长期存活的机制和条件的理解。
