STRUCTURAL-CHANGES IN THE GILL CELLS OF GAMMARUS-DUEBENI (CRUSTACEA, AMPHIPODA) UNDER OSMOTIC-STRESS - WITH NOTES ON MICROTUBULES IN ASSOCIATION WITH THE SEPTATE JUNCTIONS

The amphipod crustacean Gammarus duebeni (Lilljeborg) tolerates salini ties in the range freshwater to seawater. Such tolerance requires the ability to respond to the varying degrees of osmotic stress imposed on the single layer of epithelial cells separating the outside medium fr om the haemolymph space in the gills. Following transfer of individual s from low salinities to seawater, changes occur in the fine structure of the epithelial cells. These changes invoke the configuration of th e apical border of the cells, the mitochondria and cytoplasmic lacunae . Despite such variation in cell organisation, the association between neighbouring epithelial cells appears unaffected. Attention is drawn to a well developed system of microtubules in association with the sep tate junctions. The possible mechanical role of these microtubules in protecting the integrity of the septate junctions from the effects of osmotically induced changes in cell volume is discussed.