Arsenic resistance paper on PeerJ Preprints
ShadeLab grad student Taylor Dunivin (@TaylorDunivin) has submitted her first paper to PeerJ Preprints, “Diversity and mechanisms of arsenic resistance among soil bacteria impacted by the ongoing Centralia coal mine fire”. The paper is co-authored by Justine Miller, a former undergraduate rock star in ShadeLab.
In this work, we investigated microbial soil arsenic resistance at the site of the Centralia underground coal mine fire, which has been burning since 1962. Arsenic is a naturally occurring byproduct of anthracite coal combustion. In Centralia, soils are exposed to arsenic when coal combustion products percolate upward from the fire to deposit near the surface. Thus, we asked how microbial arsenic resistance in this site compared to other contaminated soils, given the extreme press disturbance of the Centralia fire. From a hot Centralia surface soil, we isolated bacteria resistant to arsenite and arsenate, and characterized their growth phenotypes, arsenic transformation capabilities, genotypes relating to known genes conferring arsenic resistance, and phylogenetic diversity as assessed by sequence of the 16S rRNA gene.
We found that the most prevalent resistance mechanisms were those that are known to increase arsenic solubility in the local environment, including arsenate reduction and arsenite efflux. This is interesting because other studies have reported a prevalence of arsenic oxidation in sites with comparably high arsenic contamination, suggesting that chronic but relatively low arsenic exposure may result in different mechanisms of resistance that ultimately could more severe implications for public health. We also found evidence for horizontal gene transfer of arsC (reductase) among these isolates, suggesting that chronic exposure compounded with transferable mechanisms of resistance can intensify local arsenic solubility. We apply an ecological perspective to these results by discussing the importance of disturbance intensity and duration in determining community robustness, and the role that transferable mechanisms of specialized stress response can play in shaping that robustness.
Check out the beautiful phenotypic diversity of Taylor's arsenic resistance isolates:
Feedback on the Preprint is welcomed!