Karino S, Hiwatashi K
Mech Ageing Dev. 1984 Jul;26(1):51-66. doi: 10.1016/0047-6374(84)90164-7.
A diversity of time when increase in mortality after conjugation occurs during the lifespan was found in subclones of three stocks of Paramecium caudatum. A possible micronuclear contribution to the increase in sterility has been investigated by micronuclear transplantation. We found two classes of micronuclei in aged clones: those that can function normally if the cytoplasmic environment is young, and those that cannot, even in a young cytoplasmic environment. The results indicate that in the former, the age-dependent increase in sterility is due to a deleterious macronucleus and/or cytoplasm, and in the latter it is due to micronuclear damage. The micronuclear damage in aged clones is probably induced by a deleterious cytoplasmic environment because aged clones with transplanted young micronuclei showed an abrupt decrease in progeny survival between 14 and 42 cell divisions after transplantation. Overall, the micronucleus seems not to be a source of age-related damage but rather is subjected to damage from macronuclear and/or cytoplasmic sources.
在尾草履虫的三个品系的亚克隆中发现，接合后死亡率增加在寿命期间出现的时间存在多样性。通过微核移植研究了微核对不育性增加的可能贡献。我们在老龄克隆中发现了两类微核：一类在细胞质环境年轻的情况下能够正常发挥功能，另一类即使在年轻的细胞质环境中也不能正常发挥功能。结果表明，在前者中，不育性随年龄增长的增加是由于有害的大核和/或细胞质，而在后者中则是由于微核损伤。老龄克隆中的微核损伤可能是由有害的细胞质环境诱导的，因为移植了年轻微核的老龄克隆在移植后14至42次细胞分裂之间后代存活率急剧下降。总体而言，微核似乎不是与年龄相关损伤的来源，而是受到来自大核和/或细胞质来源的损伤。
