Effect of Polycyclic Aromatic Hydrocarbons on Development of the Ascidian Type A.

Polycyclic aromatic hydrocarbons (PAHs) are pollutants that exert harmful effects on marine invertebrates; however, the molecular mechanism underlying PAH action remains unclear. We investigated the effect of PAHs on the ascidian type A (). First, the influence of PAHs on early development was evaluated. PAHs such as dibenzothiophene, fluorene, and phenanthrene resulted in formation of abnormal larvae. PAH treatment of swimming larva induced malformation in the form of tail regression. Additionally, we observed the () mRNA expression in swimming larva, mid body axis rotation, and early juvenile stages. The time correlation between PAH action and mRNA expression suggested that Ci-AhR could be associated with PAH metabolism. Lastly, we analyzed mRNA localization in juveniles. mRNA was localized in the digestive tract, dorsal tubercle, ganglion, and papillae of the branchial sac, suggesting that Ci-AhR is a candidate for an environmental pollutant sensor and performs a neural function. Our results provide basic knowledge on the biological function of Ci-AhR and PAH activity in marine invertebrates.