Evidence for an intermediate type of spermatozoon: ultrastructural studies of spermiogenesis in the cuttlefishRossia macrosoma (Cephalopoda, Decabrachia)

Autor: W. L. Maxwell, S. T. Hou
Rok vydání: 1992
Předmět:
Zdroj: Zoomorphology. 112:207-215
ISSN: 1432-234X
0720-213X
DOI: 10.1007/bf01632818
Popis: Testes and spermatophores of the decapod cephalopodRossia macrosoma have been investigated by electron microscopy. Cytochemical analysis, by use of the periodic acid thiosemicarbazide-silver proteinate (PA-TSC-SP) technique, allows the precise localization of glycogen within the spermatozoon. Nuclear morphogenesis occurs in three stages (termed A, B and C), resulting in the transformation of the nucleus from an ovoid shape (stage A) into an elongated form (stages B and C). Prior to elongation of the spermatid nucleus, the spheroidal proacrosome, derived from the Golgi complex, becomes located at the apex of the nucleus. Later, the proacrosome elongates and its internal contents differentiate into an apical vesicle, electron-dense rod and electron-lucent subacrosomal fossa. A longitudinal microtubular manchette is closely associated with the elongating proacrosome. At this stage, the spermatid nucleus also elongates and its associated microtubular manchette is continuous with that surrounding the proacrosome. Large quantities of glycogen granules,β-particles, about 130–145 A in diameter, occur in the midpiece in relation to both the specialized external plasma membrane of the mitochondrial sleeve and within or around the axonome in the tail piece. We compare the features of spermiogenesis and the spermatozoon ofR. macrosoma with those documented in the literature for species from a number of phyla with the so-called primitive type of spermatozoon and which practise external fertilization, and the modified type in species practising internal fertilization. We suggest that the spermatozoon and spermiogenesis ofRossia demonstrates characteristics intermediate between these two groups and that the spermatozoon should be classified as an intermediate type.
Databáze: OpenAIRE
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