Effects of heavy metals on transcription and enzyme activity of Na+/K+-ATPase in the monogonont rotifer, Brachionus koreanus

Heavy metals can lead to osmotic stress by disrupting the regulation of sodium ion in aquatic organisms. In this study, gene expression patterns and enzymatic activities of Na + /K + -ATPase in the monogonont rotifer, Brachionus koreanus were measured after exposure to different Cd (7.5, 15, and 30 mg/L), and Pb (0.1, 0.5, and 1.0 mg/L), respectively. As results, a significant increase in Bk Na + /K + -ATPase activity was observed after exposure to Cd and Pb in a concentration-dependent manner. Bk Na + / K + - ATPase mRNA level was significantly upregulated in the Cd-exposed group, whereas its level was reduced in the Pb-exposed group. These findings indicate that heavy metals could induce osmotic stress in B. koreanus , and Na + /K + -ATPase may be involved in cellular ho-meostasis in response to heavy metal exposure. This study is helpful for the understanding of the molecular mode of action of B. koreanus in response to heavy metals.