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 evaluate the attachment and colonization characteristics as well as the cytotoxic effects of the piscine bacterium, Mycoplasma mobile 163 K on piscine gill epithelium. Light, scanning and transmission electron microscopy were applied in this study and revealed heavy colonization of mycoplasmas on gill rakers, resulting in severe tissue damage of the gill epithelium. The complications for the function of the gills during breathing, the mechanisms of cytotoxicity, and the validity of this newly-established in vitro model are discussed in detail. In addition, anatomical specialities designated as spikes were identified on the inner surface of the gill rakers from trout; these could be used in the differentiation of fish.