Anatomical and Physiological Characteristics of Tentacular Nematocytes Isolated by Different Methods from Aiptasia diaphana (Cnidaria: Anthozoa) in the Brackish Pond Faro (Messina, Italy)
We studied the effects of isolation on anatomical and functional characteristics of nematocytes isolated from tentacles of Aiptasia diaphana, an anthozoan living in the brackish pond Faro (Messina) where salinity can change for both climatic and anthropic reasons. The anatomical effects of isolation were investigated by scanning electron microscopy (SEM). To evaluate the functional effects, the capacity to regulate cell volume under a 35% hyposmotic shock (Regulatory Volume Decrease, RVD) was measured by image computer processing of the sagittal area. Furthermore the membrane integrity was revealed by applying Trypan blue.The isolation using a physical method was performed by heat dissociation (45δC for 20 min), while, as a chemical method, we used a treatment of tissue with SCN−. The isolated nematocytes revealed different characteristics both anatomical and physiological, although the Trypan blue test showed that in both cases the cell membrane was not damaged. In particular nematocytes isolated by heat dissociation show the mechanosensorial apparatus while those isolated by SCN− appeared to be deprived of this structure. As far as the volume regulation is concerned, the cells isolated by heat dissociation did not appear to regulate their volume until the hypotonic treatment was maintained. On the other hand the nematocytes isolated by SCN− regulate volume in hypotonic conditions.
KeywordsCellular Element Regulatory Volume Decrease Regulatory Volume Increase Hypotonic Condition Image Computer Processing
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