An ultrastructural examination of developing and mature euspermatozoa in pyrazus ebeninus (Mollusca, Gastropoda, Potamididae)

Healy J.M. (1982) An ultrastructural examination of developing and mature euspermatozoa in pyrazus ebeninus (Mollusca, Gastropoda, Potamididae). Zoomorphology, 100 3: 157-175. doi:10.1007/BF00311970


Author Healy J.M.
Title An ultrastructural examination of developing and mature euspermatozoa in pyrazus ebeninus (Mollusca, Gastropoda, Potamididae)
Journal name Zoomorphology   Check publisher's open access policy
ISSN 0720-213X
Publication date 1982-01-01
Sub-type Article (original research)
DOI 10.1007/BF00311970
Volume 100
Issue 3
Start page 157
End page 175
Total pages 19
Publisher Springer-Verlag
Subject 2702 Anatomy
1103 Clinical Sciences
Abstract Mature and developing euspermatozoa of the prosobranch gastropod Pyrazus ebeninus, have been examined using transmission electron microscopy and phase-contrast light microscopy. The head of the mature euspermatozoon consists of a conical acrosome capping a short, rod-shaped nucleus (laterally compressed posteriorly). A basal invagination in the nucleus contains the proximal portion of the axoneme and a dense attachment matrix. Four apparently non-helical mitochondrial elements (two large, two small) comprise the midpiece each being composed of curved, inclined cristal plates and a granular matrix. The structure and arrangement of the mitochondrial elements is thus distinguishable from the helical midpiece elements found in euspermatozoa of neogastropods and most mesogastropods and possibly is widespread in the Cerithiacea. A dense ring-like structure is found closely applied to the inside of the plasma membrane at the junction of midpiece and glycogen piece. Acrosome and midpiece formation and nuclear condensation have been studied in developing euspermatozoa. Acrosome development is divided into two phases: (1) a pre-attachment phase - during which a complex early acrosome is formed often at great distance from the nuclear apex, and (2) an attachment/post-attachment phase - during which the completed preattachment phase acrosome tilts into position at the nuclear apex and subsequently elongates. The nucleus passes through a recognizable sequence of condensation phases (reticular, fibrillar and lamellar phases). Microtubules surround both the nucleus and midpiece in the final phase of maturation. The four, elongate midpiece elements of the mature euspermatozoon are apparently derived from the four large, spherical mitochondria of the euspermatid. The potential usefulness of spermatozoal ultrastructure with regard to indicating affinities between groups of gastropod families is briefly discussed.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Scopus Import
 
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