Advanced Biotechnology Center, University of Yamanashi, 4-4-37 Takeda, Kofu-shi, Yamanashi, Japan.
Faculty of Life and Environmental Sciences, University of Yamanashi, Yamanashi, Japan.
Sci Rep. 2019 Apr 5;9(1):5719. doi: 10.1038/s41598-019-42062-8.
It has long been believed that tolerance against extreme environments is possible only for 'lower' groups, such as archaea, bacteria or tardigrades, and not for more 'advanced' species. Here, we demonstrated that the mammalian sperm nucleus also exhibited strong tolerance to cold and hot temperatures. When mouse spermatozoa were freeze-dried (FD), similar to the anhydrobiosis of Tardigrades, all spermatozoa were ostensibly dead after rehydration. However, offspring were obtained from recovered FD sperm nuclei, even after repeated treatment with conditions from liquid nitrogen to room temperature. Conversely, when FD spermatozoa were heated at 95 °C, although the birth rate was decreased with increasing duration of the treatment, offspring were obtained even for FD spermatozoa that had been heat-treated for 2 h. This period was improved up to 6 h when glucose was replaced with trehalose in the freeze-drying medium, and the resistance temperature was extended up to 150 °C for short periods of treatment. Randomly selected offspring grew into healthy adults. Our results suggest that, when considering the sperm nucleus/DNA as the material that is used as a blueprint of life, rather than cell viability, a significant tolerance to extreme temperatures is present even in 'higher' species, such as mammals.
长期以来，人们一直认为，只有“较低”的生物群体，如古菌、细菌或缓步动物，才有可能耐受极端环境，而“更高级”的物种则不然。在这里，我们证明了哺乳动物精子核也具有很强的耐冷耐热能力。当小鼠精子被冻干（FD）时，类似于缓步动物的脱水休眠，所有精子在复水后表面上都已死亡。然而，从恢复的 FD 精子核中获得了后代，甚至在经过液氮到室温的反复处理后也是如此。相反，当 FD 精子在 95°C 下加热时，尽管处理时间延长，出生率会下降，但即使 FD 精子已加热处理 2 小时，仍能获得后代。当冻干介质中的葡萄糖被海藻糖取代时，这一时间延长至 6 小时，并且抵抗温度延长至 150°C 以下的短时间处理。随机选择的后代成长为健康的成年人。我们的结果表明，当将精子核/DNA 视为生命蓝图的物质，而不是细胞活力时，即使是“更高”的物种，如哺乳动物，也具有很强的耐极端温度的能力。
