FIG. 4.

Overexpression of tol1⁺ or HAL2 gene improved LiCl tolerance (A) but did not affect NaCl tolerance (B) in S. pombe. Saturated cultures of wild-type cells transformed with the multicopy plasmid pDB248 (○; vector), pDB248[tol1⁺] (●; ptol1⁺), or pDB248[HAL2] (□; pHAL2) were diluted in fresh minimal medium supplemented with various concentrations of LiCl (A) or NaCl (B) as indicated. Growth was recorded by measurement of the absorbance at 660 nm after 18 h. Data were averaged from three independent experiments, each sample done in duplicate. The bars indicate standard errors of the mean.