Developmental toxic effects of three alternative booster biocides on embryonic flounder (Paralichthys olivaceus): Approach to morphogenesis and Transcription analysis

Abstract

To compare the toxic effects of antifouling alternative booster biocides on non-target pelagic fish (flounder) embryos, we investigated the adverse effects of developmental malformation and transcriptional changes. Three biocides including Diuron, Irgarol 1051® and Sea-Nine 211® produced a largely overlapping suite of developmental malformations, including tail-fin fold defects and dorsal body axis curvature. In our test, the potencies of these biocides were ranked in the following order with respect to malformation and mortalities: Sea-Nine 211® > Irgarol 1051® > Diuron. Consistent with the toxicity rankings, the expression of genes related to heart formation was greater in embryonic flounder exposed to Sea-Nine 211® than in those exposed to Irgarol 1051® or Diuron, while expression of genes related to fin malformation was greater in the Irgarol 1051® exposure group. In analyses of differential gene expression (DEG) profiles (fold change of genes with a cutoff P < 0.05) by high-throughput sequencing (RNA-seq), genes associated with nervous system development, transmembrane transport activity, and muscle cell development were significantly changed commonly. Embryos exposed to Diuron showed changes related to cellular protein localization, whereas genes associated with immune system processes were up-regulated significantly in embryos exposed to Irgarol 1051®. Genes related to actin filament organization and embryonic morphogenesis were up-regulated in embryos exposed to Sea-Nine 211®. Overall, our study provides a better understanding of the overlapping and unique developmental toxic effects of three commercial booster biocides through transcriptomic analyses in a non-target species, embryonic flounder.