Dataset Information

Stable isotope probing analysis of the diversity and activity of methanotrophic bacteria in soils from the Canadian high Arctic.

ABSTRACT: The melting of permafrost and its potential impact on CH(4) emissions are major concerns in the context of global warming. Methanotrophic bacteria have the capacity to mitigate CH(4) emissions from melting permafrost. Here, we used quantitative PCR (qPCR), stable isotope probing (SIP) of DNA, denaturing gradient gel electrophoresis (DGGE) fingerprinting, and sequencing of the 16S rRNA and pmoA genes to study the activity and diversity of methanotrophic bacteria in active-layer soils from Ellesmere Island in the Canadian high Arctic. Results showed that most of the soils had the capacity to oxidize CH(4) at 4 degrees C and at room temperature (RT), but the oxidation rates were greater at RT than at 4 degrees C and were significantly enhanced by nutrient amendment. The DGGE banding patterns associated with active methanotrophic bacterial populations were also different depending on the temperature of incubation and the addition of nutrients. Sequencing of the 16S rRNA and pmoA genes indicated a low diversity of the active methanotrophic bacteria, with all methanotroph 16S rRNA and pmoA gene sequences being related to type I methanotrophs from Methylobacter and Methylosarcina. The dominance of type I methanotrophs over type II methanotrophs in the native soil samples was confirmed by qPCR of the 16S rRNA gene with primers specific for these two groups of bacteria. The 16S rRNA and pmoA gene sequences related to those of Methylobacter tundripaludum were found in all soils, regardless of the incubation conditions, and they might therefore play a role in CH(4) degradation in situ. This work is providing new information supporting the potential importance of Methylobacter spp. in Arctic soils found in previous studies and contributes to the limited body of knowledge on methanotrophic activity and diversity in this extreme environment.

SUBMITTER: Martineau C

PROVIDER: S-EPMC2935073 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

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Stable isotope probing analysis of the diversity and activity of methanotrophic bacteria in soils from the Canadian high Arctic.

Martineau Christine C Whyte Lyle G LG Greer Charles W CW

Applied and environmental microbiology 20100709 17

The melting of permafrost and its potential impact on CH(4) emissions are major concerns in the context of global warming. Methanotrophic bacteria have the capacity to mitigate CH(4) emissions from melting permafrost. Here, we used quantitative PCR (qPCR), stable isotope probing (SIP) of DNA, denaturing gradient gel electrophoresis (DGGE) fingerprinting, and sequencing of the 16S rRNA and pmoA genes to study the activity and diversity of methanotrophic bacteria in active-layer soils from Ellesme ...[more]

PMID: 20622133

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Project description:The growth and activity of bacteria have been extensively studied in nearly every environment on Earth, but there have been limited studies focusing on the air. Suspended bacteria (outside of water droplets) may stay in the atmosphere for time frames that could allow for growth on volatile compounds, including the potent greenhouse gas methane. We investigated the ability of aerosolized methanotrophic bacteria to grow on methane in the airborne state in rotating gas-phase bioreactors. The physical half-life of the aerial bacterium-sized particles was 3 days. To assess the potential for airborne growth, gas-phase bioreactors containing the aerosolized cultures were amended with 1,500 ppmv 13CH4 or 12CH4. Three of seven experiments demonstrated 13C incorporation into DNA, indicating growth in air. Bacteria associated with the genera Methylocystis and Methylocaldum were detected in 13C-DNA fractions, thus indicating that they were synthesizing new DNA, suggesting growth in air. We conclude that methanotrophs outside of water droplets in the air can potentially grow under certain conditions. Based on our data, humidity seems to be a major limitation to bacterial growth in air. Furthermore, low biomass levels can pose problems for detecting 13C-DNA synthesis in our experimental system. IMPORTANCE Currently, the cellular activities of bacteria in the airborne state outside of water droplets have not been heavily studied. Evidence suggests that these airborne bacteria produce ribosomes and metabolize gaseous compounds. Despite having a potentially important impact on atmospheric chemistry, the ability of bacteria in the air to metabolize substrates such as methane is not well understood. Demonstrating that bacteria in the air can metabolize and grow on substrates will expand knowledge about the potential activities and functions of the atmospheric microbiome. This study provides evidence for DNA synthesis and, ultimately, growth of airborne methanotrophs.

Dataset Information

Stable isotope probing analysis of the diversity and activity of methanotrophic bacteria in soils from the Canadian high Arctic.

Publications

Stable isotope probing analysis of the diversity and activity of methanotrophic bacteria in soils from the Canadian high Arctic.

Similar Datasets

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