An analysis on nuclear differentiation and the continuity of germ line during conjugation of Paramecium caudatum

草履虫的每个细胞都有一个生发微核和一个体细胞大核。在有性期，由微核减数分裂产物产生的雌性和雄性原核融合产生受精。受精核分裂3次，产生新的大核和微核。同时，受精卵前期的大核碎裂并随后退化。由此可见，胚系由微核延续。在本工作中，微核的行为得到了如下结果：1)配子发生和受精时的微核对于接合后的口部发生是必不可少的。根据对无性体微核的分析，其对口腔发生的作用并不是由于微核中的几个特异基因所致。因此，可能的假设是，微核具有支持接合后口腔形成的组织中心的作用。抗α-微管蛋白抗体检测结果表明，微核行为与微管动力学密切相关。2)电子显微镜观察了减数分裂产物的退化过程。当凝集素WGA在4核阶段注入细胞(1 mg/ml，约35pl)时，可防止这种退化。当细胞内注射WGA-金结合物时，金颗粒出现在溶酶体样结构处。WGA似乎直接或间接地与细胞质因子结合，产生核并阻止它们退化。3)在外接合子中，假定有4个微核。在合子后的细胞分裂中，只有1个细胞分裂，另外3个没有分裂。

Each cell of Paramecium caudatum has a germinal micronucleus and a somatic macronucleus. During sexual phase, a fertilization is produced by fusion of a female and a male pronucluei derived from meiotic products of the micronucleus. The fertilization nucleus divides 3 times and gives rise to produce new macronuclei and micronuclei. Meantime, the prezygotic macronucleus fragments and degenerates later on. Thus, germ line continued by the micronucleus. In the present work, the following results were obtained with the behavior of the micronucleus.1) The micronucleus at gametogeneisis and fertilization is indispensable for the postconjugationa stomatogenesis. According to the analysis of nulisomic micronuclei, the function on the stomatogenesis is not due to a few specific genes of the micronucleus. Therefore, the possible hypothesis is that the micronucleus has a role to support the organizing center for postconjugational stomatogenesis. The results investigated by the anti-alpha-tubulin antibody showed evidences that the micronuclear behavior was closely related with the dynamics of microtubics.2) Degeneration process of the meiotic products was followed by electron microscopy. A lectin WGA prevented this degeneration when it was injected into cells (1mg/ml, ca. 35pl) at the stage of 4 nuclei. When WGA-Gold conjugate was injected in the cells, the gold particles appeared at the lysosome like structures. WGA seems to bind directly or indirectly to the cytoplasmic factor to generate the nuclei and prevented them from degenerating.3) In the exconjugants, there are 4 presumptive micronuclei. At postzygotic cell divisions, only one of them divided and other 3 did not.