Project description:Chemostat incubations were established and inoculated with sediments collected from Canyon Creek, Calgary, Alberta, Canada. The chemostats experienced oxic-anoxic change of different frequency, High-frequency, Medium-frequency and Low-frequency. 18 samples were collected at the end of the final oxic phase and the final anoxic phase in the triplicated chemostats for metagenomic and metaproteomic analysis. 26 genomes were assembled from metagenomes. Proteomes were used to investigate translational regulation of each population associated with a genome.
Project description:This SuperSeries is composed of the following subset Series: GSE15272: Diurnally synchronized transitions between oxic and anoxic physiologies in an archaeon, experiment "A" GSE15273: Diurnally synchronized transitions between oxic and anoxic physiologies in an archaeon, experiment "B" GSE15274: Diurnally synchronized transitions between oxic and anoxic physiologies in an archaeon, experiment "Control-1" GSE15275: Diurnally synchronized transitions between oxic and anoxic physiologies in an archaeon, experiment "C" GSE15276: Diurnally synchronized transitions between oxic and anoxic physiologies in an archaeon, experiment "Control-2" Refer to individual Series
Project description:The aim of this study is to investigate the transcriptional response of S. Typhimurium to heat, osmotic, oxidative and acid stress under anoxic and oxic conditions and to non-stressed anoxic conditions.
Project description:Crude oil is the one of the most important natural assets of humankind, yet it is a major environmental pollutant, in particular, in marine environments. One of the largest crude oil polluted areas in the word is the semi-enclosed Mediterranean Sea, where the metabolic potential of indigenous populations towards the chronic pollution at a large scale is yet to be defined, particularly in anaerobic and micro-anaerobic marine sites. Here, we provided a novel insight into the active microbial metabolism in sediments from three environments along the coastline of Italy. Microbial proteomes exhibited prevalence in anaerobic metabolism, not related to the biodegradation directly, suggesting the strong limitation by oxygen induced by the carbon overload. They also point at previously unrecognized metabolic coupling between methane and methanol utilizers as well as sulfur reducers in marine petroleum polluted sediments.
Project description:The abundance of bacterial (AOB) and archaeal (AOA) ammonia oxidisers, assessed using quantitative PCR measurements of their respective a-subunit of the ammonia monooxygenase (amoA) genes, and ammonia oxidation rates were measured in four contrasting coastal sediments in the Western English Channel. Sediment was sampled bimonthly from July 2008 to May 2011, and measurements of ammonia oxidiser abundance and activity compared to a range of environmental variables including salinity, temperature, water column nutrients and sediment carbon and nitrogen content. Despite a higher abundance of AOA amoA genes within all sediments, and at all time-points, rates of ammonia oxidation correlated with AOB and not AOA amoA gene abundance. Other than ammonia oxidation rate, sediment particle size was the only variable that correlated with the spatial and temporal patterns of AOB amoA gene abundance, implying a preference of the AOB for larger sediment particles. This is possibly due to deeper oxygen penetration into the sandier sediments, increasing the area available for ammonia oxidation to occur, higher concentrations of inhibitory sulphide with pore waters of muddier sediments or a combination of both oxygen and sulphide concentrations. Similar to many other temporal studies of nitrification within estuarine and coastal sediments, decreases in AOB amoA gene abundance were evident during summer and autumn, with maximum abundance and ammonia oxidation rates occurring in winter and early spring. The lack of correlation between AOA amoA gene abundance and ammonium oxidation rate suggests an alternative role for amoA-carrying AOA within these sediments.
Project description:Methanogenic and methanotrophic archaea produce and consume the greenhouse gas methane, respectively, using the reversible enzyme methyl-coenzyme M reductase (Mcr). Recently, Mcr variants that can activate multi-carbon alkanes have been recovered from archaeal cultures. These enzymes, called alkyl-coenzyme M reductase (Acrs), are widespread in the environment but remain poorly understood. Here, we produced anoxic cultures degrading mid-chain petroleum n-alkanes from pentane (C5) to tetradecane (C14) at 70°C using oil-rich Guaymas Basin sediments. In these cultures, archaea of the genus Candidatus Alkanophaga activate the alkanes with Acrs and completely oxidize the alkyl groups to CO2. Ca. Alkanophaga form a deep-branching sister clade to the methanotrophs ANME-1 and are closely related to the short-chain alkane oxidizers Ca. Syntrophoarchaeum. Incapable of sulfate reduction, Ca. Alkanophaga shuttle electrons from alkane oxidation to the sulfate-reducing Ca. Thermodesulfobacterium syntrophicum. These syntrophic consortia are potential key players in petroleum degradation in heated oil reservoirs.
Project description:In order to ensure the reproducibility of the transcriptional response of Halobacterium NRC-1 to oxic/anoxic transitions, we repeated global mRNA measurements for the oxygen time series data in GSE5924, except that cultures were equilibrated to high oxygen for 12 hours prior to the start of the experiment rather than low oxygen. The results of these data suggest that there is good (~60%) reproducibility between datasets, and that Halobacterium responds robustly to oxic/anoxic transitions. Keywords: time series