Spermatozoa morphology changes during reproduction and first observation of acrosomal contact in two dioecious species of Macrobiotidae (Tardigrada: Eutardigrada)
Spermatozoa morphology changes during reproduction and first observation of acrosomal contact in two dioecious species of Macrobiotidae (Tardigrada: Eutardigrada)
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DOI：
10.1017/s0967199420000490
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发表时间：
2021-02-01
期刊：
影响因子：
1.7
通讯作者：
Matsumoto, Midori
中科院分区：
文献类型：
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作者：
Sugiura, Kenta;Matsumoto, Midori
两种雌雄异株真姬鼠的交配行为：一株副大生物体。和SacroBiotus shonaicus(Stec等人，2018年)，观察表明，这两个物种的精子首先被释放到环境中，然后游过雌性泄殖腔进入受精囊。配子核的融合尚未发生在产卵中。因此，有人认为受精是在外部完成的，因为卵子在配子核融合之前被释放到环境中。在本研究中，两种副顶生线虫的精子。精子在生殖过程中发生了形态变化。在形态计量学分析中，精子的尾部、中段、细胞核和顶体明显长于副顶体。与Sonaicus相比。两种动物的睾丸精子和精囊精子的核都是卷曲的，但后者的尾巴较短。这些精子在产卵后出现在卵绒毛膜表面。顶体的顶端埋在绒毛膜中，这表明已经发生了穿透。我们还提出，缩小的尾巴是一种保守的特征，至少在大型生物科中是这样。
Mating behaviours for two species of dioecious eutardigrades: a strain of Paramacrobiotus sp. and Macrobiotus shonaicus (Stec et al., 2018) have been recorded previously, and observations have indicated that spermatozoa of both species are first released into the environment, then swim through the cloaca of the females and into the spermatheca. The fusion of gamete nuclei has not yet occurred in a laid egg. Therefore, it has been suggested that fertilization is completed externally as the egg is released into the environment before the nuclei of the gametes fuse. In the present study, the spermatozoa of both Paramacrobiotus sp. and M. shonaicus spermatozoa underwent morphological changes during reproduction. In morphometrical analyses of testicular spermatozoa, the tail, mid-piece, nucleus, and acrosome were significantly longer in Paramacrobiotus sp. compared with M. shonaicus. The nuclei of both the testicular and spermathecal spermatozoa were equally coiled, but the latter had shorter tails in both species. These spermatozoa were present on the surface of the egg chorion after oviposition. The tip of the acrosomes lay buried in the chorion, suggesting that penetration had occurred. We also proposed that the reduced tail is a conserved trait, at least in Macrobiotidae.