FIG. 2.

NO enhances biofilm formation in biofilms that are undergoing anaerobic respiration. (A) Biofilm mass of wild-type N. gonorrhoeae strain 1291 in the absence of nitrite (1) and in the presence of 20 μM SNP (2) after 2 days of growth. Biofilms were grown for 24 h in the presence of nitrite and then transitioned to media without nitrite that either did or did not contain SNP. Experiments were performed a minimum of two times, and a representative result is depicted in panel A. N. gonorrhoeae was visualized by GFP expression, and these images are three-dimensional reconstructions of stacked z series taken at a magnification of ×200 and rendered by Volocity. (B) Graphs showing COMSTAT analyses of biomass and average thickness. There was a significant difference between biofilms with nitrite and those without nitrite, as determined by Student's t test (P < 0.001).