ATTACHMENT OF MYCOPLASMA-MOBILE 163-K TO PISCINE GILL ARCHES AND RAKERS - LIGHT, SCANNING AND TRANSMISSION ELECTRON-MICROSCOPIC FINDINGS

Explant cultures of gill arches and rakers were established to evaluat e the attachment and colonization characteristics as well as the cytot oxic effects of the piscine bacterium, Mycoplasma mobile 163 K on pisc ine gill epithelium. Light, scanning and transmission electron microsc opy were applied in this study and revealed heavy colonization of myco plasmas on gill rakers, resulting in severe tissue damage of the gill epithelium. The complications for the function of the gills during bre athing, the mechanisms of cytotoxicity, and the validity of this newly -established in vitro model are discussed in detail. In addition, anat omical specialities designated as spikes were identified on the inner surface of the gill rakers from trout; these could be used in the diff erentiation of fish.