Publications by authors named "Trine Aakvik"

2 Publications

  • Page 1 of 1

High coverage sequencing of DNA from microorganisms living in an oil reservoir 2.5 kilometres subsurface.

Environ Microbiol Rep 2011 Dec 14;3(6):674-81. Epub 2011 Sep 14.

Statoil ASA, 7053 Ranheim, Norway Department of Biotechnology, Norwegian University of Science and Technology, 7491 Trondheim, Norway Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway SINTEF Materials and Chemistry, Department of Biotechnology, 7465 Trondheim, Norway CEES and MERG, Department of Biology, University of Oslo, 0316 Oslo, Norway.

Microorganisms colonize a variety of extreme environments, and based on cultivation studies and analyses of PCR-amplified 16S rDNA sequences, microbial life appears to extend deep into the earth crust. However, none of these studies involved comprehensive characterizations of total DNA. Here we report results of a high-coverage DNA pyrosequencing of an apparently representative and uncontaminated sample from a deep sea oil reservoir located 2.5 km subsurface, attributing a pressure and temperature of 250 bars and 85°C respectively. Bioinformatic analyses of the DNA sequences indicate that the reservoir harbours a rich microbial community dominated by a smaller number of taxa. Comparison of the metagenome with sequences in databases indicated that there may have been contact between the oil reservoir and surface communities late in the sequence of geological events leading to oil reservoir formation. One specific gene, encoding a putative enolase, was synthesized and expressed in Escherichia coli. Enolase activity was confirmed and was found to be much more thermotolerant than for a corresponding E. coli enzyme, consistent with the conditions in the oil reservoir.
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http://dx.doi.org/10.1111/j.1758-2229.2011.00279.xDOI Listing
December 2011

A plasmid RK2-based broad-host-range cloning vector useful for transfer of metagenomic libraries to a variety of bacterial species.

FEMS Microbiol Lett 2009 Jun 4;296(2):149-58. Epub 2009 May 4.

Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway.

The majority of microorganisms in natural environments are difficult to cultivate, but their genes can be studied via metagenome libraries. To enhance the chances that these genes become expressed we here report the construction of a broad-host-range plasmid vector (pRS44) for fosmid and bacterial artificial chromosome (BAC) cloning. pRS44 can be efficiently transferred to numerous hosts by conjugation. It replicates in such hosts via the plasmid RK2 origin of replication, while in Escherichia coli it replicates via the plasmid F origin. The vector was found to be remarkably stable due to the insertion of an additional stability element (parDE). The copy number of pRS44 is adjustable, allowing for easy modifications of gene expression levels. A fosmid metagenomic library consisting of 20 000 clones and BAC clones with insert sizes up to 200 kb were constructed. The 16S rRNA gene analysis of the fosmid library DNA confirmed that it represents a variety of microbial species. The entire fosmid library and the selected BAC clones were transferred to Pseudomonas fluorescens and Xanthomonas campestris (fosmids only), and heterologous proteins from the fosmid library were confirmed to be expressed in P. fluorescens. To our knowledge no other reported vector system has a comparable potential for functional screening across species barriers.
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http://dx.doi.org/10.1111/j.1574-6968.2009.01639.xDOI Listing
June 2009
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