Anoxygenic photosynthesis also had the capacity to change the earth's geochemistry pretty significantly. Historically, geologists have looked to the rock record to infer the rise of oxygen on earth, and one of the things that they've pointed out as having been produced by molecular oxygen have been sedimentary structures called banded iron formations. These are comprised of alternating layers of chert and iron oxides. But back in 1993, when Friedrich Widdel and Bernhard Schink and coworkers reported the existence of anoxygenic phototrophs that could use iron in their metabolisms and directly produce these iron oxides as a product, the simple ability to observe ferric minerals in banded iron formations and, hence, infer oxygen was present on earth at the time to form them, no longer became quite so obvious. One of the motivations for my group is being able to tell the difference when you're looking at a banded iron formation, whether it was produced in a world that was totally anaerobic, and at what point in history did those banded iron formations reflect the emergence of molecular oxygen. It's probably going to take the rest of my career for us to find a good answer to that.
Your work has also extended to arsenate respiration, by which microbes "breathe" arsenate, making a much more toxic compound, arsenite. Arsenic contamination in drinking water is a big problem in many places around the world. Can these discoveries about arsenate respiration help improve how we handle arsenic-contaminated water?
That's the hope. What we've done is develop ways of identifying when arsenic respiration is occurring at the molecular level. This won't solve the problem, it will only show that there is a problem and it will motivate efforts to aerate the system in such a way that this process is no longer stimulated. In the end, I think that the problem of arsenic mobilization in places like Bangladesh is a very complicated one that integrates many factors outside of science. There isn't a simple fix.
Some of your work in ancient anaerobic metabolisms may have impacts on treating bacterial infections. What's the link between ancient metabolisms and infection?
For years, organisms had to develop strategies for electron transfer under anaerobic conditions. Today, in the context of infections, many of these infections are anaerobic and therefore, when we think about it metabolically, the strategies organisms are taking to survive might not be all that different from strategies that developed on an anaerobic world billions of years ago. My favorite example of electron transfer in these type of multicellular environments that are relevant for infection is Pseudomonas aeruginosa and other species that make small molecular electron shuttles that are also known as redox-active antibiotics. We started to ask whether or not these molecules were always toxic, particularly under anaerobic conditions, where you no longer have the mechanism of generating superoxide (which makes them toxic). We tested the hypothesis that these could be electron shuttling molecules to diverse oxidants not just oxygen, and we found that indeed they were very versatile redox active molecules and could react with iron oxides and produce ferrous iron. This would be a pretty clever strategy for organisms to acquire iron under anaerobic conditions.
This year, you've been awarded ASM's Eli Lilly Award in recognition of your many accomplishments as a young researcher. That's a very prestigious award.
I was incredibly honored by that and totally shocked. I heard about it when I was on maternity leave and it was a really nice shot in the arm because at the time my brain was sort of decaying and I wasn't sure I was ever going to be able to do science again. Getting this recognition was a pep talk for me.
What is your favorite microbe? Why?
I've always loved Pyrococcus furiosus. Partly I love it just because of the name - I think it's a really great name. It's also a fascinating organism because of the environment in which it lives, at high temperatures, and the kind of interesting inorganic reactions it can catalyze. I love all the different organisms we've worked with in my lab over the years. I can't choose, they're all really wonderful.
If you could name a new microbe right now, would you name it after yourself? If not, how would you name it?
I would name it after Terry Beveridge, who was one of my dear mentors, both a geomicrobiologist and medical microbiologist who very tragically passed away of cancer at the end of last year.
What advice would you give students about life as a microbiologist working in academia?
I would say to follow their passion and be honest with themselves about what that is and always try to maintain a high standard for themselves regarding how they conduct their work that comes from their own sense of how they want to go out and do things. Always do something because you love it and, hopefully, the rest will take care of itself.
What is something about you that most people don't know?
They probably don't know that I have an eight month old baby boy named Ronen. Also, I was born in Argentina and I have a really great tango musician as a godfather. He's no longer alive - his name was Ástor Piazzolla.