FIG. 2.

Toluene-dependent O₂ uptake activity (A), acetate-dependent O₂ uptake activity (B), and cell viability (C) in B. cepacia G4 cells following exposure to alkenes. Resting suspensions (2.1 mg of cells ml⁻¹) of toluene-grown cells were incubated with 1.36 μmol of TCE (■), ethylene (▴), or no substrate (●) for selected times, harvested, and assayed for toluene-dependent O₂ uptake activity, acetate-dependent O₂ uptake activity, and cell viability. Viability was measured by colony counts on LB agar plates. Toluene-grown cells were also pretreated with 2-hexyne to inactivate toluene 2-monooxygenase and then incubated with TCE (⧫). The inset in panel C depicts cell viability as a function of the amount of TCE degraded. For each graph (except the inset), values are the means of two experiments.