Figure 2. CLS in response to various concentrations of NaHS. Cells were treated with different concentration of NaHS at the early and the late phases of growth. (A–G) Viabilities of Cells treated with or without NaHS at the indicated time were plotted. Arrows indicate the time of NaHS treatment. Triplicate cultures were used to achieve mean ± SD of viabilities. *p < 0.05, **p < 0.01, ***p < 0.001.