Effects of tributyltin(IV) chloride on the gametes and fertilization ofAscidia malaca (Ascidiacea: Tunicata)

Ascidia malaca gametes before fertilization incubated in 10(-5) or 10(-7) M solutions of tributyltin(IV) chloride, TBTCl, for 3 h appear highly damaged under transmission electron microscopy observation. Also, the fertilization process is affected by the compound: the damaged spermatozoa are present in the vitelline coat and the egg does not cleave. An increase of microbodies, structurally similar to peroxisomes, have been detected in the egg peripheral cytoplasm, probably in relation to their role in alleviating damage to some cellular components. The results have shown that the reproduction of ascidians under unfavourable environmental conditions is prevented. Copyright (C) 2003 John Wiley Sons, Ltd.