Modulation of ecdysteroid and juvenile hormone signaling pathways by bisphenol analogues and polystyrene beads in the brackish water flea Diaphanosoma celebensis.

Owing to its high production and world-wide usage, plastic pollution is an increasing concern in marine environments. Plastic is decomposed into nano- and micro-sized debris, which negative affect reproduction and development in aquatic organisms. Bisphenol A (BPA), an additive of plastic, is released into the water column upon plastic degradation, and is known as a representative endocrine-disrupting chemical. However, the reproductive effects of plastics and bisphenols at the molecular level have not yet been explored in small marine crustaceans. In this study, we investigated the effects of polystyrene (PS) beads (0.05, 0.5, and 6 - μm) and bisphenol analogues (BPs; BPA, BPS, and BPF) on reproduction and development of small marine crustaceans. Effects on transcriptional changes in ecdysteroid and juvenile hormone (JH) signaling pathway-related genes were examined in the brackish water flea Diaphanosoma celebensis exposed to PS beads and BPs for 48 h. As results, BPs and PS beads delayed emergence time of first offspring, and increased fecundity in a concentration-dependent manner. BPs differentially modulated the expression of ecdysteroid and JH signaling pathway-related genes, indicating that BP analogs can disrupt endocrine systems via mechanisms different from those of BPA. PS beads was also changed the gene expression of both pathway, depending on their size and concentration. Our findings suggest that BP analogues and PS beads disrupt the endocrine system by modulating the hormonal pathways, affecting reproduction negatively. This study provides a better understanding of the molecular mode of action of BPs and PS beads in the reproduction of small crustaceans.