FIG. 1.

Fluorescence microscopic images of P. acnes upon incubation with a fluorescein-labeled GPPPQGGRPQ peptide. P. acnes was suspended in a phosphate buffer containing 1.1 mM NaH₂PO₄, 1 mM NaH₂PO₄, and 100 mM NaCl, pH 6.5, and incubated with GPPPQGGRPQ (10 μM) (A), fluorescein-labeled CGKRK (10 μM) (B), or fluorescein-labeled GPPPQGGRPQ (1 μM [C] and 10 μM [D and E]) for 1 h at 37°C under anaerobic conditions. Incubation of fluorescein-labeled CGKRK was performed to exclude nonspecific binding. (F) P. gingivalis incubated with fluorescein-labeled GPPPQGGRPQ (10 μM). The green fluorescence (arrows) indicated that fluorescein-labeled peptide bound to P. acnes. (E) The green fluorescence was entirely quenched when a high concentration (1 mM) of unlabeled GPPPQGGRPQ was added to the incubation of fluorescein-labeled peptide (1 μM) with bacteria. Bar, 1 μm.