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 metals interact within microbial systems using model organisms. In particular, we are interested in examining how mixed metal and other mixed waste exposure impacts the carbon metabolism of animal intestinal microbiota.