Fig. 4.

Gaseous environment alters P. dendritiformis biofilm formation. (A) Biofilm formation quantified by Congo Red staining of P. dendritiformis grown in the presence/absence of O₂ and NO. A₅₀₀/A₆₀₀ is a measurement of the amount of Congo Red bound to the cell pellet relative to the cell density. Differences between all measurements are significant (P < 0.003). (B) Comparison of the relative in vitro DGC and PDE activities of DcpG in various ligation states [Fe(II)-O₂, Fe(II), and Fe(II)-NO] and P. dendritiformis biofilm formation when grown under aerobic, anaerobic, and anaerobic +NO conditions.