Spermiogenesis and spermatozoon of Echinostoma caproni (Platyhelminthes, Digenea): Transmission and scanning electron microscopy, and tubulin immunocytochemistry

Carlo Iomini, J. L. Justine

Research output: Contribution to journalArticle

Abstract

Spermiogenesis and the spermatozoon of Echinostoma caproni (from experimentally infested laboratory mice) were investigated by several methods. Transmission electron microscopy shows that spermiogenesis consists of a proximo-distal fusion of three processes followed by elongation of the spermatid. Scanning electron microscopy shows that the spermatozoon is a filiform cell, 235 μm in length, with a cylindrical anterior extremity and a broader posterior extremity. Epifluorescence microscopy, including immunocytochemistry of tubulin and labelling of nucleus with specific dyes, has provided valuable additional information. Migration of the nuclei from the common cytoplasmic mass of spermatids to the distal part of the elongating spermatids is visualized, and centrioles demonstrated in the proximal, anterior region, and the nucleus in the distal, posterior region of the spermatozoon. One axoneme has a distal extremity which in the mature spermatozoon extends 30 μm more distally than the other, with the result that the posterior part of the spermatozoon contains a single axoneme and the nucleus. Immunocytochemistry experiments show that a region, 15 μm in length, not labelled by the anti-tubulin antibodies with certain fixation-permeabilization procedures, corresponds to a region which, by transmission electron microscopy, shows external ornamentation on the membrane. This region has a bilaterally asymmetric pattern (in TEM), forms angles or coils according to the fixation used, and marks the boundary between two distinct patterns of movement. Spermiogenesis and the spermatozoon in E. caproni correspond to the general pattern found in the digeneans, with the exception of this asymmetric region. It is emphasized that the use of various methods provides a better understanding of sperm structure than transmission electron microscopy alone, particularly in the case of long, filiform spermatozoa.

Original languageEnglish (US)
Pages (from-to)107-118
Number of pages12
JournalTissue and Cell
Volume29
Issue number1
DOIs
Publication statusPublished - Jan 1 1997
Externally publishedYes

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Keywords

  • Digenea
  • Immunocytochemistry
  • Platyhelminthes
  • Tubulin
  • Ultrastructure

ASJC Scopus subject areas

  • Developmental Biology
  • Cell Biology

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