两种蝇类精细胞发育过程中细胞核的变态

本文用透射电子显微镜研究了大头金蝇(hrysomyia megacephala)和肥须亚麻蝇(Parasarcophaga crassipalpis)精细胞发育过程中细胞核的变态过程.精细胞从球形细胞演变为线形精子,核要经历四个时期,即:球核期,细胞为球形,核亦为球形,核膜与一般体细胞核无异;棒核期,核拉长如棒,顶体形成,核膜孔聚集于一侧;染色质凝聚期,染色质与核质分开,经过一系列变化,再凝聚成致密的块状,多余核质从核孔聚集处开口排出核外;成熟期,核变成一团电子密度极大的腊肠形.精细胞抛弃绝大部分细胞质和多余的结构,变成线形精子.以上演变过程两种蝇类完全相似,但在染色质凝聚期的变化中差异却很大:大头金蝇凝聚程序为:细纤维—粗纤维—块状—致密团;肥须亚麻蝇则为:蚁蚕状—纵列薄片状—厚片状—块伙—致密团.

DEVELOPMENT OF THE SPERMATID NUCLEI DURING SPERMIOGENESIS IN TWO FLIES

The development of the spermatid nuclei during spermiogenesis of the oriental latrine Chry-somya megacephala and the flesh fly Parasarcophaga crassipalpis are divided into four phases, namely the spherical nucleus phase containing round spermatid cells with spherical nuclei en-veloped with double membrane; the rodded nucleus phase with fenestration of the nucleus envelope confined to a lateral region; the chromatin agglutination phase with chromatin separated from nucleoplasm, agglutinated to form a dene mass after elimination of the excessive nucleo-plasm from the nucleus; and the maturation phase with the mass of highly condensed chromatin taking a sausage shape and elimination of excessive plasm and structures from the sper-matid to form a thread-shaped spermatozoon. The two flies do not differ at the first, second and fourth phases, but differ at the third phase. The agglutination process of chromatin in the-oriental latrine is of thte filamentary type while that of the flesh fly is of the laminary type.