Clostridium perfringens, a strictly anaerobic micro-organism and inhabitant of the human intestine, has been shown to produce the azoreductase enzyme AzoC, an NAD(P)H-dependent flavin oxidoreductase. This enzyme reduces azo dyes to aromatic amines, which are carcinogenic in nature. A significant amount of work has been completed that focuses on the activity of this enzyme; however, few studies have been completed that focus on the physiology of azo dye reduction. Dye reduction studies coupled with C. perfringens growth studies in the presence of ten different azo dyes and in media of varying complexities were completed to compare the growth rates and dye-reducing activity of C. perfringens WT cells, a C. perfringens ΔazoC knockout, and Bifidobacterium infantis, a non-azoreductase-producing control bacterium. The presence of azo dyes significantly increased the generation time of C. perfringens in rich medium, an effect that was not seen in minimal medium. In addition, azo dye reduction studies with the ΔazoC knockout suggested the presence of additional functional azoreductases in this medically important bacterium. Overall, this study addresses a major gap in the literature by providing the first look, to our knowledge, at the complex physiology of C. perfringens upon azo dye exposure and the effect that both azo dyes and the azoreductase enzyme have on growth.
BradfordM. M.1976; A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein–dye binding. Anal Biochem 72:248–254 [View Article][PubMed]
Encinas-YocupicioA. A., Razo-FloresE., Sánchez-DiazF., dos SantosA. B., FieldJ. A., CervantesF. J.2006; Catalytic effects of different redox mediators on the reductive decolorization of azo dyes. Water Sci Technol 54:165–170 [View Article][PubMed]
MorrisonJ. M., JohnG. H.2013; The non-enzymatic reduction of azo dyes by flavin and nicotinamide cofactors under varying conditions. Anaerobe 23:87–96 [View Article][PubMed]
MorrisonJ. M., WrightC. M., JohnG. H.2012; Identification, isolation and characterization of a novel azoreductase from Clostridium perfringens
. Anaerobe 18:229–234 [View Article][PubMed]
MorrisonJ., DaiS., RenJ., TaylorA., WilkersonM., JohnG., XieA.2014; Structure and stability of an azoreductase with an FAD cofactor from the strict anaerobe Clostridium perfringens
. Protein Pept Lett 21:523–534 [View Article][PubMed]
RafiiF., ColemanT.1999; Cloning and expression in Escherichia coli of an azoreductase gene from Clostridium perfringens and comparison with azoreductase genes from other bacteria. J Basic Microbiol 39:29–35 [View Article][PubMed]