Physiological responses of microorganisms to mixed waste contamination
We are examining the systems-level effects of multiple metal exposure in microorganisms. While many studies have explored the impacts of individual metals on bacterial physiology, multiple metals will frequently co-exist at elevated levels in contaminated sites. Using a native Bacillus cereus isolate from a contaminated site, we have found that metals in combination impact cell physiology in a manner that could not have been predicted from summing phenotypic responses to the individual metals. Exposure to this metal mixture induced a global iron starvation response not observed during exposure to the individual metals. Disruption of iron homeostasis decreased the activity of iron-cofactor-containing enzymes that are critical for cellular metabolism.
Moving forward, we are further dissecting the mechanisms through which cells maintain intracellular metal homeostasis during periods of multi-metal systems using model microorganisms.