ISSN:
1432-0878
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The fine structure of the spermatids in late stages of the differentiation, which appeared in the testis of early pupa of the silkworm Bombyx mori Linné, was studied in the electron imcroscope, being fixed in buffered (pH 8.2) 2.5% osmium tetroxide or 3% potassium permanganate. The clear band differentiates into elaborated elements consisting of an array of at least 12 membranes which run loosely winding along the major axis of the spermatid. The elaborated clear band, i. e., clear band derivatives, may be an apparatus to facilitate the activity of spermatozoa, since they are present along the full length of the remarkably elongated premature spermatozoa. It has been revealed that the clear band derivatives possess a highly ordered, fine structure which is seen to be of a paracrystalline nature. The periodic pattern has first occurred along the long axis of the clear band derivatives. After such structure is decomposed into an apparently homogeneous material, a characteristic periodic pattern occurs again crossed the major axis of the clear band derivatives, the significance of such ultrastructural changes remaining obscure. The tubular structure appears through the head part of the developing spermatids, revealing even in an apical region where the nucleus is not visible, and it appears enlarged at the base of the nucleus, but no more visible in the tail piece. In the stages when the clear band becomes progressively specialized, the tubular structure appears attached to the nucleus, although it situated at the peripheral part of the cell in a more early stage of the differentiation. The tubule is incompletely separated into two layers by a dense septum projected from the tubular wall, suggesting that such structure provides the tubule with a relatively large interior surface for metabolic reactions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00344333
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