Fig. 6.

Three putative azo-reducing strains of F. nucleatum degrade Acid Orange 7 in vitro. The absorbance of light at 550 nm (corresponding to the absorbance spectra of Acid Orange 7) was measured in cultures of F. nucleatum, B. fragilis, and C. clostridiforme isolate cultures. F. nucleatum strains were grown in BHI media and were compared with BHI-blank control mixture, whereas B. fragilis and C. clostridiforme strains were grown in YCFA media and were thus compared with a YCFA-blank. Each strain was grown and tested in biologic and technical triplicates. Each data point on the plot above is the average of three technical replicates from a single biologic replicate per strain. Please see Materials and Methods for more details regarding our experimental methodology. Asterisks indicate statistical significance calculated via two-sided t tests (*P < 0.05; **P < 0.01; ***P < 0.001).