【摘要】 四膜虫接合膜上的小孔是两接合体细胞质相连的通道。配子核形成后,按合膜由于增生而出现装有细胞器等的囊状折叠,并可脱离下来而落入另一细胞中,这可能是胞质交流的又一途径。配子核的交换不是从膜上原有小孔通过的,而是在溶酶体等作用下、使膜破裂,由核后方的微管推动进入对侧细胞中。 本文记述了四膜虫S1有性生殖过程中接合区的形态和配子核的交换。更多还原

【Abstract】 The formation of the conjugation membrane and the exchange of the gamete nuclei in the starvation-induced conjugating pairs of the Shanghai strain Sl of T. pyriformis were investigated electron-microscopically. The conjugation membrane is formed by the side to side approaching of the deciliated pellicles of the 2 conjugants. Proes or cytoplasmic connections papear on the membrane after the oral zones of the two conjugants are incorporated into the membrane. Dictyosomes, mainly in the form of simple saccules or less frequently in stacks of 2, 3 or even up to 7 saccules, mitochondria, lysosomes and coated vesicles of various sizes markedly increase in number in the cytoplasm near the conjugation membrane, giving the impression of higher metabolic activities in this region. Some of the diotyosomes merge into the conjugation membrane. The growth of the conjugation membrane gives rice to bag-like outgrowths which, with the enclosed cytoplasm and organelles of one conjugant, may break off from the membrane and drop to the cytoplasm of the other. The migration of the gamete nudeus is performed by the pushing of the microtubules at its back. When the gamete nucleus comes into contact with the conjugation membrane, small vesicular swellings usually appear at the front part of the nuclear envelope and lysosomes accumulate simultaneously in the region of the cytoplasm of the other cell opposite the gamete nucleus. It is believed that by actions of the lysosomal enzymes and probably also the secretion of the vesiculated nulear envelope the conjugation membrane in front of the two migrating gamete nuclei collapess into pieces, thus permitting the passage of gamete nuclei. The synchronized movement of the gamete nuclei and the dynamic changes of the cytoplasm of the two conjugants, especially the accumulation of the lysosomes in front of the approaching gamete nuclei of the complementary conjugants suggest the occurrence of a certain mechanism of coordination in the conjugating pair.更多还原