Accession Number 012VV-0004
Document Delivery 012VV: Document Delivery available
Authors Culioli JL. Foata J. Mori C. Marchand B.

Author e-mail Address jculioli@univ-corse.fr
Title Spermiogenesis and sperm in Mesostoma viaregginum (Plathelminthes, Rhabdocoela): an ultrastructural study to infer sperm orientation
Source Zoomorphology. 125(1):47-56, 2006 Mar.
Abbreviated Source Zoomorphology. 125(1):47-56, 2006 Mar.
Copyright Publisher SPRINGER, 233 SPRING STREET, NEW YORK, NY 10013 USA. URL: http://www.springeronline.com

ISSN 0720-213X
Author Keywords Ultrastructure. Spermiogenesis. Spermatozoon. Rhabdocoela. Mesostoma viaregginum.

KeyWords Plus Intercentriolar body. Temnocephala-novaezealandiae. Phylogenetic significance. Functional-aspects. Including notes. Genital system. Craspedella sp. Platyhelminthes. Spermatozoa. Proseriata.

Abstract Spermiogenesis in Mesostoma viaregginum begins with the formation of a zone of differentiation containing striated rootlets, two centrioles, and an intercentriolar body in-between. These centrioles generate two parallel free-flagella with the 9+"1" pattern of the Trepaxonemata growing out in opposite directions. Spermatid differentiation is characterised by a 90 degrees latero-ventral rotation of flagella and a subsequent disto-proximal centriolar rotation, with a distal cytoplasmic projection. The former rotation involves the compression of a row of cortical microtubules and allows recognising a flagellar side and an aflagellar side in the late spermatid and in the mature spermatozoon. At the end of the differentiation, centrioles and microtubules lie parallel to the spermatid axis. The disto-proximal centriolar rotation is proposed as a synapomorphy for the Rhabdocoela. The modifications of the intercentriolar body during spermiogenesis and the migration of the nucleus and the centrioles towards the cytoplasmic distal projection are also described. The mature spermatozoon of M. viaregginum is filiform and tapered at both ends and presents many features found in the Rhabdocoela gametes. The nucleus disappears before the flagellar insertion and a density gradient of mitochondria is observed along the sperm axis. The anterior end of the spermatozoon of M. viaregginum is characterised by a tapering capped by a membrane expansion. This study has enabled us to describe precisely the orientation of spermatozoa in the Rhabdocoela in general: the centriolar extremity is proposed as the anterior one for the Rhabdocoela. [References: 50]
Language English
Publication Type Article
Subset Current Contents(R)/Agriculture, Biology & Environmental Sciences.
CC Categories Animal Sciences in Current Contents(R)/Agricultural, Biology & Environmental Sciences.
Entry Week 2006 week 11
Reprint Address Reprint available from: Culioli JL. Univ Corse, Fac Sci & Tech, Lab Modeles Ecol Mediterraneenne, F-20250 Corte, France, .
Institution Reprint available from:
Culioli JL
Univ Corse, Fac Sci & Tech, Lab Modeles Ecol Mediterraneenne
F-20250 Corte
France