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TBT‐induced apoptosis in tunicate haemocytes
Author(s) -
Cima Francesca,
Ballarin Loriano
Publication year - 1999
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/(sici)1099-0739(199910)13:10<697::aid-aoc916>3.0.co;2-#
Subject(s) - tunicate , chemistry , apoptosis , microbiology and biotechnology , biochemistry , ecology , biology
Early events in apoptosis include chromatin condensation followed by DNA fragmentation as well as translocation of phosphatidylserine (PS) in the outer plasma membrane. Organotin compounds increase intracellular Ca 2+ levels and cause apoptosis in mammalian cells. In investigating whether TBT may also induce apoptosis in haemocytes of the ascidian Botryllus schlosseri , we exposed haemocytes to this xenobiotic at the sublethal dose of 10 µ M , causing cell shrinkage and inhibition of phagocytosis and respiratory burst. Apoptosis was revealed as (i) chromatin condensation, with Acridine Orange nuclear staining; (ii) DNA fragmentation, with the TUNEL reaction; (iii) PS translocation, with the annexin‐V assay; and (iv) loss of membrane permeability with the Trypan Blue diffusion assay. After 1 h of exposure, nuclear changes, i.e. significant collapse and cleavage of chromatin, were observed and cytoplasm blebbing occurred, together with surface alterations triggered by PS exposure. Haemocyte mortality increased significantly only after 2 h. All these apoptotic events may be closely related to a TBT‐induced cytosolic calcium increase resulting in activation of endonucleases. Copyright © 1999 John Wiley & Sons, Ltd.