Effect of sodium arsenite exposure on Euglena gracilis SMZ: Inhibition of growth and viability of E. gracilis SMZ exposure to sodium arsenite

To estimate the cytotoxicity of sodium arsenite (NaAsO2 on Euglena gracilis SMZ alternations of cell growth and cell viability were first assessments. Monitoring of cell growth was one of the suitable indicators to appreciate cytotoxicity of NaAsO2 because of previous reports indicated that growth of E. gracilis was inhibited by treatment of Cu Zn Hg Pb and Cd (Devars et al. 1998; Einicker‑Lamas et al. 2002. The author assessed the cell growth to determine the arsenic concentration required for the inhibition of cell pro‑ liferates by more than 50 % of the control (IC50 or 50 % lethal concentration (LC50. In our laboratory it was sug‑ gested that NaAsO2 and dimethylarsinic acid (DMA (1.75 17.5 175 250 500 1000 and 1750μM inhibited cell growth of E. gracilis SMZ in Koren‑Hutner (K.H. medium (pH 3.5. On the basis of these results the author further investigated the effect of NaAsO2 on cell proliferation and cell viability under different concentrations in K.H. medi‑ um (pH 5.5. Exposed of NaAsO2 higher than 2 mM strongly inhibited the cell growth however the viable cell num‑ ber remained ca. 70 %. Below 750μM exposure as high as more than 90 % cells were found alive suggesting the effect of NaAsO2 would not be fatal but to lower cell proliferation activity that eventually led cells rest to survive.