FIG. 5.

Phase-contrast and fluorescence microscopic analysis of B. anthracis wild-type and ΔexsY spores treated with both Alexa Fluor 488-labeled anti-BclA MAb EF12 and TYP-PE. Spores of the wild-type Sterne (WT) and ΔexsY strains were produced on solid medium and harvested without purification. The phase-contrast images show two spores in the wild-type preparation (A) and one spore and one sac (indicated by an arrowhead) in the ΔexsY preparation (B). Fluorescence images show anti-BclA MAb staining (C and D) and TYP-PE staining (E and F) of the same material shown in the phase-contrast images. The corresponding phase-contrast, anti-BclA MAb fluorescence, and TYP-PE fluorescence images were merged to indicate overlapping staining (G and H).