Effects of bisphenol A on the development of pigmented organs in the ascidian Phallusia mammillata

Bisphenol A (BPA) is an organic compound that is used in the manufacture of polycarbonate plastic and epoxy resins and is increasingly being released into the environment. BPA can act as a teratogenic substance and an endocrine disruptor, raising concerns about its impact on humans and wildlife. Thus, in the present work, we evaluated the effects of different concentrations of BPA on ontogenetic processes in the ascidian Phallusia mammillata. The phylogenetic position of ascidians, their cosmopolitan distribution in marine ecosystems, and multiple technical advantages associated with their biology make ascidians reliable model organisms for ecotoxicology bioassays. Our investigations showed that BPA did not affect the capability of ascidian sperm to fertilize eggs, but it impaired embryonic development and caused a phenotype that was characterized by a short and kinked tail. Larvae developed from BPA-exposed embryos also presented malformations of pigmented organs such as altered pigment deposition, absence of one or both pigmented organs, and supernumerary organs. The co-exposure with 4-hydroxytamoxifen, an estrogen-related receptor (ERR) inverse agonist, rescued the normal phenotype of pigmented organs, thus supporting the hypothesis that, in ascidians, BPA exerts its teratogenic effects mainly by binding to ERR, as in vertebrate models.