Publication Abstract

Ultrastructural aspects of Myxidium gadi (Georgevitch, 1916) (Myxozoa: Myxosporea): infections in pollack (Pollachius pollachius L.) and saithe (P. virens L.)

Ultrastructural aspects of Myxidium gadi (Georgevitch, 1916) (Myxozoa: Myxosporea): infections in pollack (Pollachius pollachius L.) and saithe (P. virens L.)

S.W. Feist

Plasmodia of Myxidium gadi attached to the gallbladder epithelium of two fish species, Pollachius pollachius and P. virens, were studied by transmission electron microscopy. Plasmodia were attached to the surface of the host epithelium by cytoplasmic extensions which contained fibrillar material and terminated in a basal plate which was separated from the epithelial cells by a thin amorphous layer. The gallbladder epithelium was characterised by the presence of numerous prominent vacuoles in the apical portion of the epithelial cells. Intracellular stages of M. gadi were not observed. The unattached surface of plasmodia was covered with numerous villous projections. Internally, membrane-bound inclusions up to 55 nm in diameter were observed. These were characterised by the presence of a laminated central core and a uniformly granular cortex. Clusters of generative cells were also prominent within the plasmodia. Spore formation proceeded by direct association of sporogonic cells, although pansporoblast formation was also occasionally observed. Sporoplasmosomes were abundant in the binucleate sporoplasm cell of immature spores and appeared to be formed from the endoplasmic reticulum.

Reference:

S.W. Feist, 1995. Ultrastructural aspects of Myxidium gadi (Georgevitch, 1916) (Myxozoa: Myxosporea): infections in pollack (Pollachius pollachius L.) and saithe (P. virens L.). European Journal of Protistology, 31: 309-317.

S.W. Feist *

European Journal of Protistology, 31: 309-317