Department of Microscopy, François Rabelais University, 10 Boulevard Tonnellé, 37032, Tours, France; Faculty of Bioengineering and Bioinformatics, Moscow State University, 119991, Moscow, Russia.
Department of Microscopy, François Rabelais University, 10 Boulevard Tonnellé, 37032, Tours, France.
Arthropod Struct Dev. 2017 Mar;46(2):265-273. doi: 10.1016/j.asd.2016.11.011. Epub 2017 Jan 5.
The spermatozoon of the parasitoid wasp Cotesia congregata is an extremely short gamete measuring less than 7 μm; it is as yet the shortest flagellated sperm to be identified. The mature sperm consists of an acrosome, surrounded by an extra cellular coat, a condensed nucleus, two uncoiled mitochondrial derivatives and a short axoneme. Testes of young adults contain a continuum of differentiation stages. Initially, the flagellum is approximately 5 μm long. It conserves its length in round, elongated and mature spermatids, but is reduced to less than 3 μm in mature spermatozoa. The nucleus is 2 μm in diameter when round, 10 μm long when it becomes a long boat-hull shaped filament, and then reduces to 3.6 μm. Thus, during development the gamete reaches a total length of 15 μm before finally reducing to less than half that length. Some traits of mature sperm anatomy are similar to related species of the Braconidae family, but others seem to be specific and could be due to the shortness of the cell. This uncommon elongation and subsequent shortening of such a tiny flagellated cell constitutes a model for both nucleus and cilium development.
寄生蜂皱股猛蜂的精子是一种极短的配子，长度不到 7μm；它是目前为止所鉴定的最短的鞭毛精子。成熟的精子由顶体、细胞外被、浓缩的核、两个未卷曲的线粒体衍生物和一个短轴丝组成。幼成虫的睾丸包含一个连续的分化阶段。最初，鞭毛大约 5μm 长。在圆形、拉长和成熟的精细胞中保持其长度，但在成熟的精子中减少到不到 3μm。核在圆形时直径为 2μm，当变成长船形丝状时长 10μm，然后减少到 3.6μm。因此，在发育过程中，配子在最终缩短到不到一半长度之前达到 15μm 的总长度。成熟精子解剖结构的一些特征与 Braconidae 科的相关物种相似，但其他特征似乎是特定的，可能是由于细胞的短小。这种不常见的延长和随后的缩短构成了核和纤毛发育的模型。
