Formation of the microtubule bundle and helical shaping of the spermatid in the common finch, Lonchura striata var. domestica.
Spermiogenesis in the common finch with special reference to the role of microtubules constituting the microtubule bundle was examined. Microtubules first appear in a loosely grouped cluster which helically surrounds the spherical nucleus. Concurrently with the formation of a single helical bundle of microtubules, the nucleus first assumes a helical shape. With a change in microtubular array, the ridge surface of the nuclear helix becomes flattened and depressed; the gyres of the nuclear helix increase in number. During helical shaping of the acrosome, the microtubule bundle is closely associated with the posterior one gyre of the acrosomal helix with the same pitch as in the nuclear helix. At the completion of acrosomal shaping, the microtubule bundle is separated from the acrosome by the Sertoli cell process. The microtubule bundle completely disappears in the mature spermatid. It is suggested that microtubules play an important role in helical shaping of the acrosome and nucleus.
Kondo
T
T
Department of Oral Anatomy, Faculty of Dentistry, Kyushu University, Fukuoka, Japan.
Hasegawa
K
K
Uchida
T A
TA
D000177:Acrosome / Q000648:ultrastructure; D000818:Animals; D001717:Birds; D008297:Male; D008854:Microscopy, Electron; D008870:Microtubules / Q000648:ultrastructure*; D013087:Spermatids / Q000166:cytology / Q000648:ultrastructure*