Evolution of octopod sperm I: comparison of nuclear morphogenesis in Eledone and Octopus.
Morphogenesis of the Eledone cirrhosa sperm nucleus, as studied by electron microscopic techniques, is compared with that of Octopus vulgaris. Both species of cephalopods belong to the family Octopodidae. The results indicate that extensive nuclear helicoidization during E. cirrhosa spermiogenesis is brought about by modifications of the function of structural components already present in the late steps of O. vulgaris spermiogenesis. In particular, changes in the regulation of perinuclear microtubule contraction in E. cirrhosa spermatids, as well as a decrease in basicity of protamines, promote nuclear helicoidization. Disulphide bond formation between protamine molecules fixes the completely helicoidal shape of the nucleus in mature sperm of E. cirrhosa.
Department of Enginyería Química, ETSEIB, UPC, Barcelona, Spain.
Pepita
P
Gimenez-Bonafé
Enric
E
Ribes
Maria J
MJ
Zamora
Harold E
HE
Kasinsky
Manel
M
Chiva
D000818:Animals; D005075:Biological Evolution; D002467:Cell Nucleus / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D009024:Morphogenesis; D049831:Octopodiformes / Q000166:cytology*; D013091:Spermatogenesis; D013094:Spermatozoa / Q000166:cytology* / Q000648:ultrastructure