UNIQUE AZOREDUCTASE ACTIVITY OF THE PSEUDOMONAS AERUGINOSA STRAIN FRD1
Marla Ichord, Gilbert John.
Oklahoma State University, Stillwater, OK.
Nosocomial respiratory infections in cystic fibrosis patients are associated with Pseudomonas aeruginosa, which contributes to high morbidity, mortality, and antibiotic resistance in immunocompromised patients. One approach to combat this upward trend is to find a unique survival mechanism for P. aeruginosa infections. This study seeks to establish a unique mechanism of bacterial survival for the Pseudomonas aeruginosa strain FRD1, a cystic fibrosis isolate and alginate (mucoid) producing bacterium, which is phenotypically different than the nonmucoid PAO1 strain. The study specifically examines the physiology and molecular functions of strains FRD and PAO1 azoreductase activities. We hypothesize that FRD1 is uniquely different than PAO1 based on its mechanism of survival via azoreductase activity. Other investigators have extensively studied azoreductase in P. aeruginosa PAO1, as 3 proteins (paAzo-1,-2,-3) have been fully characterized. However, no published information is available regarding molecular, biochemical, and physiological parameters for P. aeruginosa FDR1. The results, after testing 10 azo dyes, determined that FRD1 is able to metabolize (OD/time) the azo dye (methyl red), compared to PAO1, suggesting unique azoreductases may be present within the bacterium. Pure enzyme studies further support unique azoreductases based on specific activity (µM dye/mg protein/min) data. Overall, results support the uniqueness of FRD1 and suggest a potential new mechanism for bacterial survival thereby increasing survivability and ultimately pathogenicity of the bacterium.