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Development of spermatozoa in the wooly opossum with special reference to the shaping of the sperm head

1970; Academic Press; Volume: 33; Issue: 3-4 Linguagem: Inglês

10.1016/s0022-5320(70)90029-8

1878-2345

David M. Phillips,

Connexins and lens biology

The spermatids of Caluromys assume an unusual T-shape due to flattening of the sperm heads in a plane perpendicular to the long axis of the cell. While the nucleus is condensing, the manchette microtubules are disposed parallel to the long axis of the cell at some distance from the nucleus. This suggests that the manchette microtubules are not primarily responsible for the ultimate shape of the condensed nucleus. Spermatids of this opossum contain a thin ring of electron dense material lateral to the nucleus which may help maintain the breadth of the nucleus, and flattening may be largely due to molding by the acrosome or closely apposed Sertoli cell. In Caluromys, as in other mammals, the dense fibers first appear as thin filaments all along the length of the flagellum and subsequently increase in diameter. The fibrous sheath first appears at a distance considerably posterior to the nucleus, leaving room for the mitochondria which will later occupy the midpiece.