An ultrastructural study of reproduction in the sporocysts of <Emphasis Type="Italic">Prosorhynchoides gracilescens</Emphasis> (Digenea: Bucephalidae) |
| |
Authors: | I M Podvyaznaya |
| |
Institution: | (1) The Laboratory of Parasitic Worms, Zoological Institute of the Russian Academy of Sciences, Universitetskaya nab., 1, St. Petersburg, 199034, Russia |
| |
Abstract: | The germinal development in Prosorhynchoides gracilescens sporocysts was studied using electron microscopy. The germinal cells proliferated and developed within multiple floating
germinal masses located in the terminal portions of sporocyst branches. The germinal masses were composed of supporting and
germinal cells. Supporting cells possessed numerous flattened extensions that spread around and between developing germinal
cells to form three-dimensional mesh network, which maintained the integrity of the germinal mass. Morphological evidences
of close interactions between supporting and germinal cells were numerous gap junctions between the two cell types and phagocytosis
of small fragments of germinal cells cytoplasm by supporting cells. The germinal cells displayed structural differences that
seemed to reflect their sequential developmental changes. These changes included (1) cell growth and increase of organelles
number, (2) dispersion of nuclear chromatin and increase of nucleolus size, (3) polarization of the cell, (4) appearance of
specific structures such as nuage and laminated inclusions. The germinal cells left the germinal masses to finish their differentiation
in the body cavity and then cleaved to give rise to cercarial embryos. Ultrastructural features of the germinal elements of
P. gracilescens sporocysts are discussed in the light of existing controversy concerning the nature of the germinal sacs reproduction. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|