Publications by authors named "Justin S Brantner"

3 Publications

  • Page 1 of 1

Response of soil-associated microbial communities to intrusion of coal mine-derived acid mine drainage.

Environ Sci Technol 2014 10;48(15):8556-63. Epub 2014 Jul 10.

Department of Biology, ‡Integrated Biosciences Program, and §Department of Geosciences, The University of Akron , Akron, Ohio 44325, United States.

A system has been identified in which coal mine-derived acid mine drainage (AMD) flows as a 0.5-cm-deep sheet over the terrestrial surface. This flow regime enhances the activities of Fe(II) oxidizing bacteria, which catalyze the oxidative precipitation of Fe from AMD. These activities give rise to Fe(III) (hydr)oxide-rich deposits (referred to as an iron mound) overlying formerly pristine soil. This iron mound has developed with no human intervention, indicating that microbiological activities associated with iron mounds may be exploited as an inexpensive and sustainable approach to remove Fe(II) from AMD. To evaluate the changes in microbial activities and communities that occur when AMD infiltrates initially pristine soil, we incubated AMD-unimpacted soil with site AMD. Continuous exposure of soil to AMD induced progressively greater rates of Fe(II) biooxidation. The development of Fe(II) oxidizing activities was enhanced by inoculation of soil with microorganisms associated with mature iron mound sediment. Evaluation of pyrosequencing-derived 16S rRNA gene sequences recovered from incubations revealed the development of microbial community characteristics that were similar to those of the mature iron mound sediment. Our results indicate that upon mixing of AMD with pristine soil, microbial communities develop that mediate rapid oxidative precipitation of Fe from AMD.
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http://dx.doi.org/10.1021/es502261uDOI Listing
October 2015

Depth-dependent geochemical and microbiological gradients in Fe(III) deposits resulting from coal mine-derived acid mine drainage.

Front Microbiol 2014 14;5:215. Epub 2014 May 14.

Department of Biology, The University of Akron Akron, OH, USA ; Integrated Bioscience Program, The University of Akron Akron, OH, USA ; Department of Geosciences, The University of Akron Akron, OH, USA.

We evaluated the depth-dependent geochemistry and microbiology of sediments that have developed via the microbially-mediated oxidation of Fe(II) dissolved in acid mine drainage (AMD), giving rise to a 8-10 cm deep "iron mound" that is composed primarily of Fe(III) (hydr)oxide phases. Chemical analyses of iron mound sediments indicated a zone of maximal Fe(III) reducing bacterial activity at a depth of approximately 2.5 cm despite the availability of dissolved O2 at this depth. Subsequently, Fe(II) was depleted at depths within the iron mound sediments that did not contain abundant O2. Evaluations of microbial communities at 1 cm depth intervals within the iron mound sediments using "next generation" nucleic acid sequencing approaches revealed an abundance of phylotypes attributable to acidophilic Fe(II) oxidizing Betaproteobacteria and the chloroplasts of photosynthetic microeukaryotic organisms in the upper 4 cm of the iron mound sediments. While we observed a depth-dependent transition in microbial community structure within the iron mound sediments, phylotypes attributable to Gammaproteobacterial lineages capable of both Fe(II) oxidation and Fe(III) reduction were abundant in sequence libraries (comprising ≥20% of sequences) from all depths. Similarly, abundances of total cells and culturable Fe(II) oxidizing bacteria were uniform throughout the iron mound sediments. Our results indicate that O2 and Fe(III) reduction co-occur in AMD-induced iron mound sediments, but that Fe(II)-oxidizing activity may be sustained in regions of the sediments that are depleted in O2.
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http://dx.doi.org/10.3389/fmicb.2014.00215DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4030175PMC
May 2014

Mathematical modelling of Pseudomonas aeruginosa biofilm growth and treatment in the cystic fibrosis lung.

Math Med Biol 2014 Jun 21;31(2):179-204. Epub 2013 Mar 21.

Department of Chemistry, University of Akron, Akron, OH, USA.

Lung failure due to chronic bacterial infection is the leading cause of death for patients with cystic fibrosis (CF). It is thought that the chronic nature of these infections is, in part, due to the increased tolerance and recalcitrant behaviour of bacteria growing as biofilms. Inhalation of silver carbene complex (SCC) antimicrobial, either encased in polymeric biodegradable particles or in aqueous form, has been proposed as a treatment. Through a coordinated experimental and mathematical modelling effort, we examine this proposed treatment of lung biofilms. Pseudomonas aeruginosa biofilms grown in a flow-cell apparatus irrigated with an artificial CF sputum medium are analysed as an in vitro model of CF lung infection. A 2D mathematical model of biofilm growth within the flow-cell is developed. Numerical simulations demonstrate that SCC inactivation by the environment is critical in aqueous SCC, but not SCC-polymer, based treatments. Polymer particle degradation rate is shown to be an important parameter that can be chosen optimally, based on environmental conditions and bacterial susceptibility.
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http://dx.doi.org/10.1093/imammb/dqt003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4571485PMC
June 2014