マルタニシ(Viviparus malleatus)の異型精子の微細構造
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概要
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The fine structure of atypical spermatozoa of Viviparus malleatus has been studied with the electron microscope (JEM-5G). Some histochemical techniques and the phase-contrast microscope have also been used to supplement electron microscopy. By means of suitable washing techniques unaffecting appreciably light microscope figures of spermatozoa, the clear pictures were able to be obtained also in electron microscopy. Atypical spermatozoa show variation in size, but contain the same fne structural elements. Each atypical spermatozoon is composed of three main parts; head, middle-piece, and tail brush with tail ends (Fig. 1-b). The head is occupied by a nucleus (N) and a bundle of axial fibres (AF) projecting from the midde-piece (Plate I-3 and Fig. 2). The nucleus gives a weakly positive Feulgen (nucleal) reaction. Each axial fibre runs through the middle-piece to the tail ens. originating from an apical centriole (AC) which is schematically shown in Plate I-4a. The axial fibre consists of a bundle of twenty longitudinal fibrils, two of which are placed in the center and nine pairs are evenly arranged arround them (Plate I-7). In the middle -piece, the axial fibres surrounded by a mosaic sheath(MS) are arranged in a cylinder enclosing an axial strand (AS). The axial strand is absent from the anterior one-third of the middle-pice(Plate I-3, 6 and 7). It is believed that the axial strand corresponds to the mitochondrial sheath (MCS) of a typical spermatozoon, because the axial strand gives positive reactions to both the Neotetrazolium method and G-Nadi reaction, and each rodlet composing the axial strand has a structure like the mitochondrial cristae (Plate I-7). The mosaic sheath is composed of a number of granules (G), each of which is enveloped by a membrane (M_1)(Plate I-7 and Fig. 3). The granules disperse easily under unsuitable conditions and then disintegrate into many filaments (fl) which dissolve in the medium (Plate II-22). The naked atypical spermatozoon is motile without the mosaic sheath. The tails and their base are most resistant to unfavorable media and mechanical shock (Plate II-21). It is suggested that the resistibility is due to the existence of both the filling matter (FM) at the base of tail brush and the membranes (M_2 and M_3) which envelop the tail sheath (Plate II-11, 13, 15 and Fig. 4). The distal ring centriole which has been believed to be located at the base of tail brush, is not found in thin sections. The tail sheaths of typical and atypical spermatozoa are rich in glycogen, and therefore the following description must be re-examined: "the products of the broken-down sheaths^<(1)> may nourish the eupyrene spermatozoa^<(2)> (Hanson, Randall, and Bayley, '52)".
- 社団法人日本動物学会の論文
- 1958-09-15