Time course of gene expression during Porphyromonas gingivalis strain ATCC 33277 biofilm formation

Abstract

Chronological gene expression patterns of biofilm-forming cells are important to understand bioactivity and pathogenicity of biofilms. For Porphyromonas gingivalis ATCC 33277 biofilm formation, the number of genes differentially regulated by more than 1.5-fold was highest during the growth stage (312/2,090 genes), and some pathogen-associated genes were time-dependently controlled.

Fig. 1.

P. gingivalis biofilm growth rate. Growth of P. gingivalis biofilm was analyzed quantitatively using the optical density method. The growth rate was not constant.

Fig. 2.

CLSM images of P. gingivalis biofilm. P. gingivalis biofilm images at 3 (A), 6 (B), 9 (C), and 14 (D) days. Scale bar, 10 μm. Live and dead cells are stained with green and red, respectively. The proportion of live to dead cells was 98.67% ± 0.10% to 1.33% ± 0.10% (A), 97.78% ± 0.40% to 2.22% ± 0.40% (B), 98.22% ± 0.17% to 1.78% ± 0.17% (C), and 98.75% ± 0.19% to 1.25% ± 0.19% (D).

Fig. 3.

Time-dependent changes for the numbers of differentially expressed genes of P. gingivalis biofilm-forming cells. The numbers of differentially expressed genes significantly upregulated (black bar) and downregulated (white bar) by more than 1.5-fold (P < 0.001, Welch t test) are shown.