Concentration-dependent transcriptome of zebrafish larvae for environmental bisphenol S assessment

Effects of parental exposure to amitriptyline on the survival, development, behavior, and gene expression in zebrafish offspring

In mammals, parental exposure to amitriptyline (AMI) has been proven to contribute to congenital disabilities in their offspring. However, no studies have paid attention to the adverse effects of parental exposure to amitriptyline on fish offspring. In this study, we exposed adult zebrafish (F0) to AMI (0.8 μg/L) for 21 days. Subsequently, these zebrafish (F0) were allowed to mate, and their offspring (F1) were collected to culture in clean water for 5 days. The mortality rate, average hatching time, and heart rate at 48 h post-fertilization (hpf) of F1 were investigated. Our results showed that parental exposure to AMI induced tachycardia and increased mortality in F1 zebrafish. Under a light/dark transition test, F1 larvae born from AMI-exposed parents exhibited lower locomotor activity in the dark period and decreased thigmotaxis in the light period. The transcriptome analysis showed that parental AMI exposure dysregulated some key pathways in their offspring. Through the prediction of key driver analysis, six differentially expressed genes (DEGs) were revealed as key driver genes involved in protein processing in endoplasmic reticulum (hspa5, hsp70.1, hsp90a), ribosome (rps27a) and PPAR signaling pathway (pparab and fabp2). Considering that the concentration of AMI residual components in natural water bodies may be over our test concentration (0.8 μg/L), our findings suggested that toxicity of parental exposure to the offspring of fish should receive greater attention.

Cytogenetic and developmental toxicity of bisphenol A and bisphenol S in Arbacia lixula sea urchin embryos

Bisphenol S (BP-S) is one of the most important substitutes of bisphenol A (BP-A), and its environmental occurrence is predicted to intensify in the future. Both BP-A and BP-S were tested for adverse effects on early life stages of Arbacia lixula sea urchins at 0.1 up to 100 µM test concentrations, by evaluating cytogenetic and developmental toxicity endpoints. Embryonic malformations and/or mortality were scored to determine embryotoxicity (72 h post-fertilization). It has been reported in academic dataset that bisphenols concentration reached μg/L in aquatic environment of heavily polluted areas. We have chosen concentrations ranging from 0.1-100 μM in order to highlight, in particular, BP-S effects. Attention should be paid to this range of concentrations in the context of the evaluation of the toxicity and the ecological risk of BP-S as emerging pollutant. Cytogenetic toxicity was measured, using mitotic activity and chromosome aberrations score in embryos (6 h post-fertilization). Both BP-A and BP-S exposures induced embryotoxic effects from 2.5 to 100 µM test concentrations as compared to controls. Malformed embryo percentages following BP-A exposure were significantly higher than in BP-S-exposed embryos from 0.25 to 100 µM (with a ~5-fold difference). BP-A, not BP-S exhibited cytogenetic toxicity at 25 and 100 µM. Our results indicate an embryotoxic potential of bisphenols during critical periods of development with a potent rank order to BP-A vs. BP-S. Thus, we show that BP-A alternative induce similar toxic effects to BP-A with lower severity.

Transcriptome analysis and protein-protein interaction in resistant and susceptible families of Japanese flounder (Paralichthys olivaceus) to understand the mechanism against Edwardsiella tarda

Edwardsiella tarda is one of the most harmful bacterial pathogens for aquaculture flatfish. After artificial infection of 47 Japanese flounder (Paralichthys olivaceus) families, resistant and susceptible families were identified in this study. High-throughput sequencing was performed on the liver transcriptome of uninfected groups (PoRU and PoSU) and infected groups (PoRC and PoSC). Through assembly and annotation, a total of 3012 and 1386 differentially expressed genes (DEGs) were identified in PoRU vs. PoSU and PoRC vs. PoSC. The significant enrichment pathways between PoRU and PoSU were mainly in metabolic and biosynthesis pathways. A total of thirty dominant enrichment pathways between PoRC and PoSC mainly focused on some immune-related pathways, including the hematopoietic cell lineage, cytokine-cytokine receptor interaction, complement and coagulation cascades, antigen processing and presentation, the intestinal immune network for immunoglobulin A (IgA) production and T/B cell receptor signaling pathway. Under the protein-protein interaction (PPI) analysis, hub genes, including CD molecules, complement component factors and chemokines, were identified in the network, and 16 core genes were differentially expressed in resistant and sustainable families in quantitative polymerase chain reaction (qPCR) validation. This study represents the first transcriptome analysis based on resistant and susceptible families and provides resistant genes to understand the potential molecular mechanisms of antibacterial function in marine fish. The results obtained in this study provide crucial information on gene markers for resistant breeding of Japanese flounder.