@article {1030,
	title = {Metagenomes of tropical soil-derived anaerobic switchgrass-adapted consortia with and without iron.},
	journal = {Stand Genomic Sci},
	volume = {7},
	year = {2013},
	month = {2013},
	pages = {382-98},
	abstract = {<p>Tropical forest soils decompose litter rapidly with frequent episodes of anoxia, making it likely that bacteria using alternate terminal electron acceptors (TEAs) such as iron play a large role in supporting decomposition under these conditions. The prevalence of many types of metabolism in litter deconstruction makes these soils useful templates for improving biofuel production. To investigate how iron availability affects decomposition, we cultivated feedstock-adapted consortia (FACs) derived from iron-rich tropical forest soils accustomed to experiencing frequent episodes of anaerobic conditions and frequently fluctuating redox. One consortium was propagated under fermenting conditions, with switchgrass as the sole carbon source in minimal media (SG only FACs), and the other consortium was treated the same way but received poorly crystalline iron as an additional terminal electron acceptor (SG + Fe FACs). We sequenced the metagenomes of both consortia to a depth of about 150 Mb each, resulting in a coverage of 26\&times; for the more diverse SG + Fe FACs, and 81\&times; for the relatively less diverse SG only FACs. Both consortia were able to quickly grow on switchgrass, and the iron-amended consortium exhibited significantly higher microbial diversity than the unamended consortium. We found evidence of higher stress in the unamended FACs and increased sugar transport and utilization in the iron-amended FACs. This work provides metagenomic evidence that supplementation of alternative TEAs may improve feedstock deconstruction in biofuel production.</p>
},
	issn = {1944-3277},
	doi = {10.4056/sigs.3377516},
	author = {Deangelis, Kristen M and D{\textquoteright}haeseleer, Patrik and Chivian, Dylan and Simmons, Blake and Arkin, Adam P and Mavromatis, Konstantinos and Malfatti, Stephanie and Tringe, Susannah and Hazen, Terry C}
}
@article {372,
	title = {Metagenomic analysis of a permafrost microbial community reveals a rapid response to thaw.},
	journal = {Nature},
	volume = {480},
	year = {2011},
	month = {2011 Dec 15},
	pages = {368-71},
	abstract = {Permafrost contains an estimated 1672 Pg carbon (C), an amount roughly equivalent to the total currently contained within land plants and the atmosphere. This reservoir of C is vulnerable to decomposition as rising global temperatures cause the permafrost to thaw. During thaw, trapped organic matter may become more accessible for microbial degradation and result in greenhouse gas emissions. Despite recent advances in the use of molecular tools to study permafrost microbial communities, their response to thaw remains unclear. Here we use deep metagenomic sequencing to determine the impact of thaw on microbial phylogenetic and functional genes, and relate these data to measurements of methane emissions. Metagenomics, the direct sequencing of DNA from the environment, allows the examination of whole biochemical pathways and associated processes, as opposed to individual pieces of the metabolic puzzle. Our metagenome analyses reveal that during transition from a frozen to a thawed state there are rapid shifts in many microbial, phylogenetic and functional gene abundances and pathways. After one week of incubation at 5 {\textdegree}C, permafrost metagenomes converge to be more similar to each other than while they are frozen. We find that multiple genes involved in cycling of C and nitrogen shift rapidly during thaw. We also construct the first draft genome from a complex soil metagenome, which corresponds to a novel methanogen. Methane previously accumulated in permafrost is released during thaw and subsequently consumed by methanotrophic bacteria. Together these data point towards the importance of rapid cycling of methane and nitrogen in thawing permafrost.},
	keywords = {Alaska, Arctic Regions, Bacteria, Carbon, Carbon Cycle, DNA, Freezing, Genes, rRNA, Metagenome, Metagenomics, Methane, Nitrogen, Nitrogen Cycle, Oxidation-Reduction, Phylogeny, RNA, Ribosomal, 16S, Soil, Soil Microbiology, Temperature, Time Factors},
	issn = {1476-4687},
	doi = {10.1038/nature10576},
	author = {Mackelprang, Rachel and Waldrop, Mark P and Deangelis, Kristen M and David, Maude M and Chavarria, Krystle L and Blazewicz, Steven J and Rubin, Edward M and Jansson, Janet K}
}
@article {376,
	title = {Microbial communities acclimate to recurring changes in soil redox potential status.},
	journal = {Environ Microbiol},
	volume = {12},
	year = {2010},
	month = {2010 Dec},
	pages = {3137-49},
	abstract = {Rapidly fluctuating environmental conditions can significantly stress organisms, particularly when fluctuations cross thresholds of normal physiological tolerance. Redox potential fluctuations are common in humid tropical soils, and microbial community acclimation or avoidance strategies for survival will in turn shape microbial community diversity and biogeochemistry. To assess the extent to which indigenous bacterial and archaeal communities are adapted to changing in redox potential, soils were incubated under static anoxic, static oxic or fluctuating redox potential conditions, and the standing (DNA-based) and active (RNA-based) communities and biogeochemistry were determined. Fluctuating redox potential conditions permitted simultaneous CO$_{2}$ respiration, methanogenesis, N$_{2}$O production and iron reduction. Exposure to static anaerobic conditions significantly changed community composition, while 4-day redox potential fluctuations did not. Using RNA:DNA ratios as a measure of activity, 285 taxa were more active under fluctuating than static conditions, compared with three taxa that were more active under static compared with fluctuating conditions. These data suggest an indigenous microbial community adapted to fluctuating redox potential.},
	keywords = {Acclimatization, Archaea, Bacteria, Carbon Dioxide, DNA, Archaeal, DNA, Bacterial, Iron, Oligonucleotide Array Sequence Analysis, Oxidation-Reduction, RNA, Archaeal, RNA, Bacterial, Soil, Soil Microbiology, Trees},
	issn = {1462-2920},
	doi = {10.1111/j.1462-2920.2010.02286.x},
	author = {Deangelis, Kristen M and Silver, Whendee L and Thompson, Andrew W and Firestone, Mary K}
}
