Figure 4

Deletion of bat loci does not alter morphology or growth of L. biflexa . (A) Electron micrographs of WT and mutant L. biflexa strains. No difference was observed in the morphology of the mutant strains relative to the WT (batA images not shown). Top panel – SEM images of L. biflexa strains; middle panel – TEM negative stains of spirochetes; bottom panels – TEM cross-section images of spirochetes. (B) Growth curves of L. biflexa strains grown with shaking (aerated cultures) or without shaking (static cultures). Data represent the mean ± the standard error calculated from quadruplicate cultures. (C) Results of co-growth of wild-type and ΔbatABD mutant in the same culture. Aerated cultures were sampled daily to determine the percent of wild-type cells (·) and of ΔbatABD mutant cells (□) in the population. Both strains remained at about the same percentage of the population throughout the timecourse, indicating that the ΔbatABD mutant did not show a competitive disadvantage during in vitro cultivation. Variations over time were not statistically significant as determined by 2-way ANOVA. Data represent the mean ± the standard error calculated from triplicate cultures.