FIG 1.

Morphology of R. sphaeroides wild-type (WT) and CL3 cells at different growth phases. R. sphaeroides WT and CL3 cells were grown aerobically in Sistrom's succinate medium at 30°C with shaking at 200 rpm until they reached log phase (absorbance of ∼0.5 at a wavelength of 600 nm) or stationary phase (absorbance of ∼1.3 at a wavelength of 600 nm). Each datum point was determined by imaging 300 cells by phase-contrast bright-field microscopy and using ImageJ to determine cell width and length. Shown are mean values ± standard deviations. Differences between the cell shape parameters of the two strains were analyzed by Student's t test. The P value for all of the parameters measured was <0.001.