| Abstrakt: |
. Nematocytes are the specialized stinging cells of cnidarians. So far, Pelagia noctiluca (Cnidaria, Scyphozoa) nematocytes have never been isolated. Taking in account the notable increase in the population of Pelagia noctiluca ('blooming') in the Strait of Messina in 1999, we performed preliminary studies on the applicability of two different methods for isolating nematocytes from tentacles and mouth arms: a chemical method, namely SCN treatment, and a physical one, namely heat dissociation. These approaches have already been employed to isolate nematocytes from Aiptasia diaphana (Anthozoa). Membrane integrity was assessed by the cytological Trypan blue test. To evaluate cell viability, the capacity to regulate cell volume was investigated under 35 % hyposmotic shock by image computer processing of sagittal sections. The results show that heat dissociation is unsuitable to isolate nematocytes because the cell membrane was damaged as revealed by cytological test. On the other hand, SCN treatment yields 90% anatomically intact, isolated nematocytes from tentacles, but not from mouth arms. Nematocytes isolated by SCN exhibit volume regulation mechanisms (RVD). These results are compared with those described in Aiptasia diaphana (Anthozoa), which lives in a different habitat. [ABSTRACT FROM AUTHOR] |
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