Spermatogenesis and postinseminational alterations of sperm structure in a Sarcoptid mite, Notoedres cati (Hering) (Acari, Acaridida, Sarcoptidae)
1988 - Volume: 29 Issue: 4 pages: 411-421
Ultrastructural features of sperm formation and their postinseminational alterations in a sarcoptid mite, Notoedres cati, were described. In the testes, the spermatogonia, spermatocytes, spermatids as well as spermatozoa are distributed in a sequence from the dorsal to the ventral region. Primary spermatocytes show the presence of a peripheral spongy layer of cytoplasm formed by ER cisternae which grow into the cytoplasm during spermatocyte division to separate the newly formed spermatids. At the spermatid stage the chromatin condenses in a form of threads, cisternae of the spongy layer become electron-dense, anastomosing ER tubules appear in the cytoplasm and the mitochondria loose their normal structure and are transformed into double piles of mitochondrial derivatives. As spermiogenesis proceeds, the thickness of the chromatin threads increases and the ER tubules become electron-dense. Spermatozoa found in the male genital tract contain thick chromatin threads freely embedded in the cytoplasm, eltron-dense ER tubules, and mitochondrial derivatives,but are devoid of the acrosomal complex. Spermatozoa observed in the seminal receptacle of the female genital tract show similar structure but are less condensed, their mitochondria reveal a more typical structure and the cytoplasmic face of the plasmalemma is incrusted with regularly distributed filaments. Contact zones can be observed between the adjacent spermatozoa. Spermatozoa characterized by long cytoplasmic protrusions and different levels of electron density were found penetrating the ovarian somatic cells.
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