FIGURE 4.

AFM deflection images showing the surface morphology of the Lactobacillus strains. The microorganisms are adhered to a poly-L-lysine-covered substrate. Imaging is performed in a 10 mM KH₂PO₄ buffer at pH 7. (a) L. johnsonii DSM20533; (b) L. johnsonii ATCC332; (c) L. johnsonii ATCC33200; (d) L. crispatus DSM20584; (e) L. helveticus ATCC12046; and (f) L. helveticus ATCC15009. The surfaces of the L. johnsonii strains exhibit a fuzzy character, whereas the definition of the surfaces of the S-layer-containing strains is higher, and the surfaces appear smoother.