Monday, September 21, 2009

Chen et al. 2008

Chen Y, Dumont MG, Neufeld JD, Bodrossy L, Stralis-Pavese N, McNamara NP, Ostle N, Briones MJI, Murrell JC. 2008. Revealing the uncultivated majority: combining DNA stable-isotope probing, multiple displacement amplification and metagenomic analyses of uncultivated Methylocystis in acidic peatlands. Environmental Microbiology 10: 2609-2622.

These authors used a multiple-methods approach to isolate and identify DNA from a group of methanotrophic prokaryotes that have previously resisted attempts at culture. These microbes were previously estimated to be highly abundant in peatland soils, and were found in soils from a range of peatlands in Europe.

The three methods used to investigate these microbes were 1. a microarray built using sequences derived from a key enzyme in the methanotrophic process, 2. DNA-SIP, DNA Stable-Isotope Probing, used to examine DNA replicated with an injection of 13C-labelled CH4 (such that only methanotrophs would be able to use the carbon in their metabolisms), and 3. MDA, Multiple-Displacement Amplification to generate sufficient template DNA for fosmid-library construction and subsequent DGGE and cladistic analysis.

This triple-combined approach allowed the isolation, identification, and some basic phylogenetic analysis of a group of ecologically-important microbes previously unstudied in such a way. From my perspective, currently the most useful parts of this paper are the references (containing reviews of metagenomics and microarrays) and the methods section, as I may be attempting similar analyses of polar desert soils.

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