Effects of Iron and Selenium on the Production of Catalase, Superoxide Dismutase, and Listeriolysin O in Listeria monocytogenes

Abstract

Listeria monocytogenes 19112, Scott A, and 10403S were grown in tryptic soy broth (TSB) and TSB supplemented with 25 to 100 μg/ml of iron (Fe) and 0.5 to 2.5 μg/ml selenium (Se) to examine the effects on catalase (CA), superoxide dismutase (SOD), and listeriolysin O (LLO) activities. Growth in TSB supplemented with Fe resulted in significant increases in CA, SOD, and LLO activities in all three strains when compared to growth in TSB. The addition of 0.5 μg/ml Se to TSB resulted in significantly higher CA and LLO activities in L. monocytogenes 19112 but showed no effect on Scott A or 10403S. These results suggest that Fe plays a role in increasing the activities of CA, SOD, and LLO.