<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Deangelis, Kristen M</style></author><author><style face="normal" font="default" size="100%">Silver, Whendee L</style></author><author><style face="normal" font="default" size="100%">Thompson, Andrew W</style></author><author><style face="normal" font="default" size="100%">Firestone, Mary K</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Microbial communities acclimate to recurring changes in soil redox potential status.</style></title><secondary-title><style face="normal" font="default" size="100%">Environ Microbiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Environ. Microbiol.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Acclimatization</style></keyword><keyword><style  face="normal" font="default" size="100%">Archaea</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Carbon Dioxide</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Archaeal</style></keyword><keyword><style  face="normal" font="default" size="100%">DNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Iron</style></keyword><keyword><style  face="normal" font="default" size="100%">Oligonucleotide Array Sequence Analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Oxidation-Reduction</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Archaeal</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil Microbiology</style></keyword><keyword><style  face="normal" font="default" size="100%">Trees</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2010</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2010 Dec</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">12</style></volume><pages><style face="normal" font="default" size="100%">3137-49</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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 CO₂ respiration, methanogenesis, N₂O 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.</style></abstract><issue><style face="normal" font="default" size="100%">12</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/20629704?dopt=Abstract</style></custom1></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Deangelis, Kristen M</style></author><author><style face="normal" font="default" size="100%">Brodie, Eoin L</style></author><author><style face="normal" font="default" size="100%">DeSantis, Todd Z</style></author><author><style face="normal" font="default" size="100%">Andersen, Gary L</style></author><author><style face="normal" font="default" size="100%">Lindow, Steven E</style></author><author><style face="normal" font="default" size="100%">Firestone, Mary K</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Selective progressive response of soil microbial community to wild oat roots.</style></title><secondary-title><style face="normal" font="default" size="100%">ISME J</style></secondary-title><alt-title><style face="normal" font="default" size="100%">ISME J</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Avena sativa</style></keyword><keyword><style  face="normal" font="default" size="100%">Bacteria</style></keyword><keyword><style  face="normal" font="default" size="100%">Biodiversity</style></keyword><keyword><style  face="normal" font="default" size="100%">Colony Count, Microbial</style></keyword><keyword><style  face="normal" font="default" size="100%">Microarray Analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Oligonucleotide Array Sequence Analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Plant Roots</style></keyword><keyword><style  face="normal" font="default" size="100%">Polymerase Chain Reaction</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Bacterial</style></keyword><keyword><style  face="normal" font="default" size="100%">RNA, Ribosomal, 16S</style></keyword><keyword><style  face="normal" font="default" size="100%">Soil Microbiology</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2009</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2009 Feb</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">3</style></volume><pages><style face="normal" font="default" size="100%">168-78</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Roots moving through soil induce physical and chemical changes that differentiate rhizosphere from bulk soil, and the effects of these changes on soil microorganisms have long been a topic of interest. The use of a high-density 16S rRNA microarray (PhyloChip) for bacterial and archaeal community analysis has allowed definition of the populations that respond to the root within the complex grassland soil community; this research accompanies compositional changes reported earlier, including increases in chitinase- and protease-specific activity, cell numbers and quorum sensing signal. PhyloChip results showed a significant change compared with bulk soil in relative abundance for 7% of the total rhizosphere microbial community (147 of 1917 taxa); the 7% response value was confirmed by16S rRNA terminal restriction fragment length polymorphism analysis. This PhyloChip-defined dynamic subset was comprised of taxa in 17 of the 44 phyla detected in all soil samples. Expected rhizosphere-competent phyla, such as Proteobacteria and Firmicutes, were well represented, as were less-well-documented rhizosphere colonizers including Actinobacteria, Verrucomicrobia and Nitrospira. Richness of Bacteroidetes and Actinobacteria decreased in soil near the root tip compared with bulk soil, but then increased in older root zones. Quantitative PCR revealed rhizosphere abundance of beta-Proteobacteria and Actinobacteria at about 10(8) copies of 16S rRNA genes per g soil, with Nitrospira having about 10(5) copies per g soil. This report demonstrates that changes in a relatively small subset of the soil microbial community are sufficient to produce substantial changes in functions observed earlier in progressively more mature rhizosphere zones.</style></abstract><issue><style face="normal" font="default" size="100%">2</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/19005498?dopt=Abstract</style></custom1></record></records></xml>