Bisphenol AF (BPAF) is extensively used as a raw material in industry, resulting in its widespread distribution in the aqueous environment. However, the effect of BPAF on the hypothalamic-pituitary-thyroidal (HPT) axis remains unknown. For elucidating the disruptive effects of BPAF on thyroid function and expression of the representative genes along the HPT axis in zebrafish (Danio rerio) embryos, whole-body total 3,3′,5-triiodothyronine (TT3), total 3,5,3′,5′-tetraiodothyronine (TT4), free 3,3′,5-triiodothyronine (FT3) and free 3,5,3′,5′-tetraiodothyronine (FT4) levels were examined following 168 h post-fertilization exposure to different BPAF concentrations (0, 5, 50 and 500 μg/L). The results showed that whole-body TT3, TT4, FT3 and FT4 contents decreased significantly with the BPAF treatment, indicating an endocrine disruption of thyroid. The expression of thyroid-stimulating hormone-β and thyroglobulin genes increased after exposing to 50 μg/L BPAF in seven-day-old larvae. The expressions of thyronine deiodinases type 1, type 2 and transthyretin mRNAs were also significantly up-regulated, which were possibly associated with a deterioration of thyroid function. However, slc5a5 gene transcription was significantly down-regulated at 50 μg/L and 500 μg/L BPAF exposure. Furthermore, trα and trβ genes were down-regulated transcriptionally after BPAF exposure. It demonstrates that BPAF exposure triggered thyroid endocrine toxicity by altering the whole-body contents of thyroid hormones and changing the transcription of the genes involved in the HPT axis in zebrafish larvae.

Vanadium (V) as minor concentration is present in various plants and extensively found in soils. The current study was established to assess the response of rice seedlings to different V concentrations and also investigated its toxic effect on growth, photosynthetic assimilation, relative chlorophyll content, SPAD index, ion leakage, enzyme activities, hydrogen peroxide (H₂O₂), and cell death. The rice seeds were sown in Petri dishes for 8 days, and after that, rice seedlings were grown hydroponically in a climate-controlled growth chamber. After 15 days of V-treatment, antioxidant enzyme activities, H₂O₂, protein contents, photosynthetic assimilation, relative chlorophyll content, and cell death were determined by utilizing the Spectrophotometer (Lambda 25 UV/VIS Spectrophotometer), and V accumulation (roots and shoots) was determined by GFAAS (GTA 120). The obtained results showed that all V concentrations significantly decreased the biomass (dry and fresh) and root growth as a result of the reduction in total root length, root tips, root fork, root surface area, and root crossing, and V was more accumulated in roots than shoots. Besides this, enzymatic activities were significantly enhanced under V stress. The findings also confirmed that seedling exposed to V stress had lower tolerance indices, photosynthetic activity, and protein contents while the ion leakage was consistently increased by increasing the V concentrations. The viability of plant cells severely damaged in response to high V stress, and H₂O₂ induction might be responsible for cell death. Generally, all V doses had a drastic effect on enzyme activities and caused cell death of rice plans. Moreover, the current study demonstrated that V ≥ 35 mg L⁻¹ caused damaging effects on rice plants.