Ultrastructural study of spermatogenesis in oscarella lobularis (porifera, demospongiae)

Elda Gaino, Bruno Burlando, Paola Buffa, Michele Sara

Risultato della ricerca: Contributo su rivistaArticolo in rivistapeer review

Abstract

The various phases of spermatogenesis in the demosponge Oscarella lobularis were studied by electron microscopy. Spermatogenesis occurs within spermatic cysts, which are presumed to derive from choanocyte chambers by transformation of choanocytes into spermatogonia. Germ cells develop asynchronously within spermatocysts, and cytoplasmic bridges, indicating incomplete cells division, connect several germ cells. Attached spermatogonia suggest gonial generations. Spermatocytes I typically show the presence of synaptonemal complexes indicating meiotic divisions. Spermatocytes II have a small size probably because of the meiotic divisions of spermatocytes I. Spermatids are characterized by an acrosome, a big mitochondrion and a peripheral sheath of condensed chromatin surrounding a clearer central area in the nucleus. The mature spermatozoon shows a lateral flagellum and a flattened acrosome capping the nucleus. The phylogenetic implications of some features of the spermatozoon are suggested.

Lingua originaleInglese
pagine (da-a)297-305
Numero di pagine9
RivistaInternational journal of invertebrate reproduction and development
Volume10
Numero di pubblicazione3
DOI
Stato di pubblicazionePubblicato - nov 1986
Pubblicato esternamente

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