Spermiation and sperm maturation in the marmoset.
The scanning and transmission electron microscopes were used to examine the processes of spermiation and sperm maturation in the marmoset. We observe that the heads of late spermatids are embedded in the apical aspect of the large sleeve-like columnar portion of Sertoli cells. As spermiogenesis progresses, spermatids become associated with numerous small apical Sertoli cell extensions. These finger-like processes undergo a sequence of changes during spermiation. Spermatozoa from the caput, corpus, and cauda epididymides were examined. In caput epididymis of marmoset, the apical segment of the spermatozoa extends well beyond the rostral edge of the nucleus and folds back on itself. In sagittal sections, the acrosome exhibits a distinct hook shape. In the corpus, the distinctive hook-shaped apical segment of the acrosome is observed in some spermatozoa, but the apical extension is significantly smaller or projects out only slightly beyond the nucleus. In cauda epididymis, the extension is absent. A similar acrosomal hook has been reported in the pigtailed monkey, which is an Old World species. We suggest that changes in acrosome structure during sperm maturation may be fairly widespread among primates.
Kumar
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Population Council, New York, New York 10021.
Phillips
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D000818:Animals; D002143:Callitrichinae / Q000502:physiology*; D004822:Epididymis / Q000166:cytology; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D012708:Sertoli Cells / Q000648:ultrastructure; D013079:Sperm Maturation / Q000502:physiology*; D013087:Spermatids / Q000648:ultrastructure; D013091:Spermatogenesis / Q000502:physiology*; D013094:Spermatozoa / Q000648:ultrastructure