Figure 4.

Photomicrographs of cells grown in different arabinose concentrations for 5 hr. (A) Sample from high arabinose culture (2.66 mM arabinose) visualized with Nomarski optics. (B) Sample from low arabinose culture (106 μM arabinose) visualized with Nomarski optics. (C) Sample from high arabinose culture (2.66 mM arabinose) visualized with epifluorescent illumination. (D) Sample from low arabinose culture (106 μM arabinose) visualized with epifluorescent illumination. In the high arabinose culture, 79% of the cells were bright. In the low arabinose sample shown, 89% of the cells became bright after addition of arabinose to 6.6 mM (0.1%).