Effect of antibiotics on cell proliferation in the Closterium peracerosum-strigosum-littorale complex (Charophyceae, Chlorophyta)

The effects of several antibiotics on the proliferation of cells of the Closterium peracerosum-strigosum-littorale complex, a unicellular charophycean alga, were examined. When cells were cultured on solid medium containing hygromycin B and phleomycin the proliferation of cells was inhibited at low concentrations of these antibiotics, with a minimum inhibitory concentration of 5.0 and 0.2 mu g/mL, respectively. By contrast, kanamycin sulfate was less effective at concentrations up to 50 mu g/mL. When cells were incubated in liquid medium containing hygromycin B and phleomycin, cell proliferation was severely inhibited at concentrations of 5.0 and 0.01 mu g/mL, respectively. It is concluded that hygromycin B and phleomycin are highly effective for inhibiting the proliferation of C. psl. complex both on solid and in liquid medium and thus are useful for the selection of the cells transformed by selectable marker genes.