A biochemical study of the effects of tributyltin on unfertilized eggs, embryos and larvae of the sea squirt Ciona intestinalis.

We have used unfertilized eggs, embryos and larvae of the sea squirt Ciona intestinalis. (Ascidiacea, Urochordata) to study the effects of tributyltin (TBT) on acetylcholine esterase (AChE) activity. Our results showed an increase of AChE enzyme activity levels after TBT exposure in both unfertilized eggs and embryos: The effects of TBT were more pronounced during the gastrula stage, while no differences between exposed larvae and controls were observed. A mechanism of TBT action on enzyme activity during ascidian embryonic development and the possibility of employing AChE in C. intestinalis as a biomarker of TBT exposure are suggested and discussed.