Fig 6. Comparing spores and sporulation rates between grouped fully virulent laboratory-adapted and wild B. anthracis strains on leaf or rock surfaces over 7 days.

Grouped laboratory-adapted strains (blue) are the averaged spore titers from Ames (UF00738) and Vollum (UF00980) and grouped wild strain values (red) are the averaged spore titers from the Ames-like (UF01106) and Vollum-like (UF01103) strains. Sporulation rates (spores/day) were calculated from the slope of the lines between each timepoints and graphed on a linear scale. Data are presented as the mean ± SEM for (A) total spores recovered from leaves, (B) total spores recovered from rocks, (C) sporulation rate from leaves, and (D) sporulation rate from rocks. The significant differences between laboratory-adapted and wild strains at each time point were determined by Mann-Whitney U tests with * = ρ < 0.05 and ** = ρ < 0.01. Significant differences in sporulation rates between days were determined by Kruskal-Wallis and Dunn’s multiple comparisons tests with leaf temporal differences identified by † = ρ < 0.05.