FIG 6.

R. sphaeroides Δcls mutant is susceptible to antibiotics targeting PG synthesis. Data represent results of spot-titer assays of R. sphaeroides wt and Δcls cells. Cell cultures in stationary phase were standardized to an absorbance of 1.0 (λ = 600 nm). We serially diluted the standardized cultures and transferred 5-μl aliquots to the surface of plates containing Sistrom’s minimal medium with 1.5% agar and sub-MICs of the antibiotics indicated (FOS [125 μg/ml], DCS [0.05 μg/ml], A22 [5 μg/ml], MEC [0.1 μg/ml], and AMP [5 μg/ml]). Plates were incubated for 72 h at 30°C.