Short communication: Differential effect of Bisphenol S, on stress and proteasome markers, during early development of Xenopus laevis tadpoles.

Bisphenol S (BPS), introduced as a replacement for Bisphenol A (BPA), demonstrates high environmental persistence across various environmental compartments, including the aquatic ecosystems. However, only a limited number of studies have investigated the effects of BPS on aquatic vertebrates. In this study, Xenopus laevis tadpoles were exposed to BPS from fertilization until 6 days post-fertilization, reaching stage 45 with a normal rate of survival. However, BPS exposure at 10-6 M and 10-4 M differentially alters levels of Hsp stress proteins. Hsp70 stress protein level remains unchanged, while Hsp90 increased, and Hsp27 decreased. Additionally, proteasome marker Rpn10 also decreased. These findings highlight that the pattern of stress protein levels and the quantity of the final proteasome effector for protein degradation are negatively affected during early development of tadpoles under BPS exposure.