What are your major research interests?
I am a geochemist, with special interest in clay mineral chemistry. Focusing on low temperature processes, I study fluid-rock interactions in many ways that benefit society and public health. In particular I investigate chemical tracers of petroleum migration, with special interest in organic and inorganic geochemical reactions. This research not only applies to the generation of hydrocarbons but also to origins of biomolecules in primordial systems. Most recently I have been studying the process(es) by which certain clay minerals kill bacteria, while others provide nutrients and energy for bacteria. Again the theme is organic interactions with inorganic systems.
As a geochemist, how did you become interested in the antibacterial properties of clay?
I was asked to image a French green clay that was used in healing Buruli ulcer, a mycobacterial ‘flesh eating’ disease. Using high-resolution field emission SEM, I examined the texture of this clay for a French humanitarian who treated people in the Ivory Coast. She had documented over 50 cases of healing the infection using this French clay, and had asked the World Health Organization to support her clinics. Without scientific validation of the process of healing with this clay, she could not be supported. Therefore, we began to seek funding to study the mechanism of healing displayed by the clay minerals that she used.
Bacterial resistance to antibiotics is a growing public health concern. Could clays with antibacterial properties be part of the solution to this problem?
While our fundamental interest is in understanding the clay healing process, it is an obvious advantage to society if we can identify the chemical or physical process responsible for the antibacterial effect. Our pilot study showed that one of the French clays completely kills E. coli; with substantial decreases in other Gram negative, Gram positive and Mycobacterial populations. A second French green clay had the opposite effect; enhancing bacterial growth. The mineralogy and major element chemistry of these clays are quite similar, therefore we seek to identify trace elements, organic compounds, chemical conditions (pH, Eh) or physical parameters (surface thermodynamic properties) that might be responsible for the disparate outcomes.
There seems to be extensive research in the field of “Geology and Health” on the risks that are posed to human health from the environment. How much focus in “Geology and Health” is on the benefits of our geological environment to human health?
Humans, like all animals, are readily focused on dangers of the immediate environment to their existence. This might explain why a majority of research in this area focuses on the geologic hazards to human health. However, the new Division of GSA (Geology and Health) encompasses medicinal applications of minerals and earth science methods as well. Humans have used minerals as health aids since the beginning of recorded history, but advances in understanding medicinal processes have been slow. As our analytical instrumentation has advanced, we now have new tools for investigating healing processes that have been identified and used primarily by methods of trial and error in traditional medicine. As geologists, our knowledge of minerals and earth materials can be best applied to medical problems in collaboration with specialists in the health industry. It takes time for the disciplinary boundaries to become penetrable, largely because we speak different languages! Not many geologists can pick up the Journal of the American Medical Association and get much out of a paper, until we learn the jargon. Similarly, my medical colleagues' eyes glaze over when I talk about boron isotope geochemistry! Our cultures are so vastly different that we first need to formulate a communication and evaluation strategy that transcends the disciplines. Research does not get far without funding. Since it is inordinately difficult to get the National Institutes of Health to fund a geologist, and perhaps even more so to get the National Science Foundation to fund an M.D., studies of the beneficial aspects of Geology and Health have been slower to develop. By necessity, Geology and Health requires open and intensive collaboration among biogeochemists, microbiologists and health professionals. One of the reasons for the formation of the new Geology and Health Division of GSA is to begin to make progress in this important direction.
Where is this area of study headed next?
My personal research is heading in the direction of imaging chemical transfers, using isotope mapping, to investigate interactions between clay minerals and the bacteria. Are there metals that under certain conditions precipitate on the cell wall and suffocate the bacteria? Are toxins entering the cell and impeding a vital function? Are the minerals robbing essential nutrients from the bacteria? Using scanning ion imaging, secondary mass spectrometry, atomic force microscopy and other new tools commonly used by geochemists, we can apply new methods to explore these fundamental questions. There is so much to be explored; the boundaries of this research area are unlimited.
You were awarded a grant from NIH in partnership with microbiologist Shelley Haydel for the study of clay mineral alternative treatment for Buruli ulcer. Tell us about your experience as a geochemist collaborating with a microbiologist.
It’s great fun! First, we work constantly on our vocabulary. We both use terminology for short cuts in conversation with our peers, but one can’t do that when the terminology is like a foreign language. For example, a microbiologist knows that ‘OD’ means optical density, but to me (an experimentalist) it means outer diameter. It gets confusing when terminology has different meanings. I need to understand that she is not talking about the outer diameter of a bacteria, but the density of their existence in a growth medium. Little things like that constantly impede our conversations and make us laugh. You can’t be afraid to say, “I don’t know what you mean by that!” and have your colleague look at you like you’re a fool! Of course I’m a fool (as a microbiologist), that’s why I need collaboration. We’re learning quickly to communicate effectively, but it’s much harder getting a grip on the detail of what she’s learned over her lifetime of study (and visa versa). We have to trust one another to be diligent in bringing forth knowledge that is pertinent to the problem at hand, and never assuming or taking any point for granted.
How important are transdisciplinary sciences to scientific research?
If by ‘transdisciplinary’ you mean transcending traditional boundaries of scientific inquiry, I’m sure everyone agrees this is where exciting discoveries CAN take place. It does not substitute for the ‘depth’ of knowledge that one must have as a specialist in their field of inquiry, but a ‘breadth’ of knowledge that lapses into a new territory is fundamentally exciting. I believe both avenues of scientific inquiry hold new treasures.
What advice would you give to students interested in Geochemistry and/or Geology and Health?
Study hard! I think it is most important to understand fundamental concepts in chemistry and physics. Don’t be afraid to ask questions, and don’t think that you have to know everything. You only have to know how to think. Observe natural processes, formulate hypotheses and perform tests. The scientific method has never changed. The only thing that has changed is our tools! Take advantage of the new tools, and think outside ‘the box’.
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