Diversity and mechanisms of arsenic resistance among soil bacteria impacted by the ongoing Centralia coal mine fire
- Published
- Accepted
- Subject Areas
- Biodiversity, Ecology, Environmental Sciences, Microbiology, Soil Science
- Keywords
- extremophiles/extremophily, microbial communities, microbial ecology, microbiology of unexplored habitats, pollution microbiology
- Copyright
- © 2016 Dunivin et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2016. Diversity and mechanisms of arsenic resistance among soil bacteria impacted by the ongoing Centralia coal mine fire. PeerJ Preprints 4:e2451v1 https://doi.org/10.7287/peerj.preprints.2451v1
Abstract
We examined diversity and mechanisms of microbial arsenic resistance in Centralia, PA, the site of an underground coal seam fire burning since 1962. From hot soil collected from an active vent, we isolated 25 unique arsenic resistant bacteria spanning six genera. Although arsenic concentrations were measured to be relatively low at the time of soil collection, isolates grew with high concentrations of arsenate and arsenite (>300mM and 20mM respectively). Among these isolates, we found genes for arsenate reduction and arsenite efflux but not methylation or oxidation. Additionally, we observed evidence for horizontal gene transfer of the arsenate reductase gene arsC. Several isolates did not test positive for any of the resistance mechanisms tested, suggesting novelty, untargeted diversity, or nonspecific mechanisms of resistance. Finally, we found that comparisons of isolate growth phenotypes across arsenic concentrations provided insights into cellular responses to arsenic. We suggest that chronic exposures to low arsenic may promote mechanisms that increase environmental solubility and enhance local toxicity (e.g., reduction, arsenite efflux), while intense exposure to arsenic may promote mechanisms that reduce environmental solubility (e.g., oxidation). Thus, disturbance intensity and duration, as well as transferability of the stress response gene(s), together inform microbial community robustness to arsenic and the fate of arsenic in the environment.
Author Comment
This article has been submitted for consideration at a journal, and previously has not undergone any formal peer review. This is a preprint submission to PeerJ Preprints.
Supplemental Information
File of isolate 16S rRNA gene and arsC sequences (.fsa)
This file contains the 16S rRNA gene sequence for each arsenic resistance isolate (25 total 16S rRNA sequences) and the arsC sequence for isolates that have this gene (determined by endpoint PCR; 12 total arsC sequences).