Wolniak S M, Klink V P, Hart P E, Tsai C W
Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, USA.
Gravit Space Biol Bull. 2000 Jun;13(2):85-93.
The spermatozoids of lower plants have long been recognized as remarkably complex motile gametes. Spermatozoids differ markedly from the other gametophyte cells that surround or give rise to them. Their differentiation process involves the synthesis and assembly of a complex cytoskeleton and a motile apparatus that can be simple or complex, having as few as two to as many as thousands of ciliary axonemes. An important aspect of spermiogenesis involves the de novo synthesis of basal bodies in a cytoplasmic particle known as the blepharoplast: that is, the cells that produce spermatocytes do not contain centrioles. Thus, these cells provide an ideal system in which to study the formation of basal bodies. The cytoskeletons of spermatozoids from different organisms display a common architecture, with a multilayered structure (MLS) at the anterior end of the cell and a dorsally situated planar ribbon of crosslinked microtubules extending the length of the elongated gamete. The function of the MLS is not known, but it could be involved in cell-body elongation during development and in the control of ciliary motility in the mature gamete, particularly during chemotaxis. The application of modern techniques on these cells can shed light on long-standing problems relating to spermiogenesis and motility.
低等植物的精子长期以来一直被认为是极其复杂的游动配子。精子与围绕它们或产生它们的其他配子体细胞有显著差异。它们的分化过程涉及复杂细胞骨架和运动装置的合成与组装，该运动装置可以简单或复杂，具有少至两个多达数千个纤毛轴丝。精子发生的一个重要方面涉及在称为生毛体的细胞质颗粒中从头合成基体：也就是说，产生精母细胞的细胞不含中心粒。因此，这些细胞提供了一个研究基体形成的理想系统。来自不同生物体的精子的细胞骨架显示出共同的结构，在细胞前端有多层结构（MLS），并且在背侧有一条交联微管的平面带，延伸至细长配子的全长。MLS的功能尚不清楚，但它可能参与发育过程中的细胞体伸长以及成熟配子中纤毛运动的控制，特别是在趋化作用期间。将现代技术应用于这些细胞可以阐明与精子发生和运动相关的长期存在的问题。
