Sperm maturation and the formation of sperm pairs in the epididymis of the opossum, Didelphis virginiana

摘要: Didelphis spermatozoa released from different levels of the epididymis exhibit a series changes that reflect events involved in process their maturation. Their progression through duct is accompanied by rotation sperm head on axis tail, an eccentric movement cytoplasmic droplet to anterior region midpiece where it discarded, appearance posterior regular submembranous electron-dense ridges, and visible condensation mitochondrial cristae matrix. The latter seems correlate generally with onset ability for progressive motility acquired most as they reach lower corpus epididymidis. This phase associated also beginnings pairing acrosomal surface characterizes mature New World marsupials. Use lectins cationized ferric colloid affinity markers served reveal occurring character tail prior pairing. This investigation strengthens idea gained previous study Australian marsupial, Trichosurus, complexity maturation Metatheria broadly comparable observed eutherian mammals.