Numerous studies have demonstrated that tardigrades in a resting state (tun state) are very resistant to exceptional stress levels in comparison with the resistance observed in multicellular organisms in general. The types of stress include desiccation and radiation, which are also relevant in astrobiological research, and therefore, tardigrades are used as multicellular model organisms. For example, tardigrades have been investigated in the TARSE, TARDIS, RoTaRad, and TARDIKISS projects; their survival has been evaluated according to stressful conditions that prevail in low earth orbit, including the effects of cosmic radiation and microgravity. Despite this interest, the study of tardigrade biology has been severely hampered by the sparsity of appropriate quantitative techniques that inform at the single-organism level. In this study, we present results on mass-specific respiration rates as a function of termination of anhydrobiosis and variations in temperature and salinity, including Mars-analog perchlorate solutions, by using microsensor technology to measure respiration. Based on our results for Richtersius cf coronifer, we estimated the activation energy (50.8 kJ/mole O₂) for its metabolism as well as Q10 for selected temperature intervals. Q10 was constant—∼1.5—between 2°C and 33°C, except for the interval 11–16°C, where Q10 was 5.5. The steady-state mass-specific respiration rate of individuals of Richtersius cf coronifer increased with increasing salinity below the lethal limit, likely representing the energy requirements of its osmoregulatory response. We report the first quantitative data of a tardigrade's metabolic dynamics during the termination of anhydrobiosis, revealing significant variation between individuals. However, we observed a general trend, that is, a high initial metabolic rate after exposure to water. Our approach would allow us to carry out quantitative physiological studies of tardigrades on board of the International Space Station, and thus significantly extend the possibility of studying the response of multicellular organisms in space.

中文翻译：

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作为温度和盐度以及脱水生物终止的函数，Richtersius cf coronifer 物种的个体缓步动物的呼吸测量

许多研究表明，与一般在多细胞生物中观察到的抵抗力相比，处于静止状态（tun 状态）的缓步动物对异常的压力水平具有很强的抵抗力。压力的类型包括干燥和辐射，这也与天体生物学研究相关，因此，缓步动物被用作多细胞模型生物。例如，在 TARSE、TARDIS、RoTaRad 和 TARDIKISS 项目中已经对缓步动物进行了调查；已经根据低地球轨道中普遍存在的压力条件，包括宇宙辐射和微重力的影响，对它们的生存情况进行了评估。尽管有这种兴趣，但在单一生物体水平上提供信息的适当定量技术的稀缺性严重阻碍了缓步动物生物学的研究。在这项研究中，我们通过使用微传感器技术测量呼吸，展示了质量特定呼吸率作为脱水生物终止和温度和盐度变化的函数的结果，包括火星模拟高氯酸盐溶液。基于我们的结果Richtersius cf coronifer，我们估计了其代谢的活化能 (50.8 kJ/mole O ₂ ) 以及选定温度区间的Q10。Q10在 2°C 到 33°C 之间是恒定的——~1.5，除了 11-16°C 的区间，其中Q10为 5.5。Richtersius cf coronifer个体的稳态质量比呼吸率随着盐度增加到致死极限以下而增加，可能代表其渗透调节反应的能量需求。我们报告了缺水生物终止期间缓步动物代谢动力学的第一个定量数据，揭示了个体之间的显着差异。然而，我们观察到一个普遍趋势，即接触水后的初始代谢率较高。我们的方法将使我们能够对国际空间站上的缓步动物进行定量生理学研究，从而显着扩展研究空间多细胞生物反应的可能性。