Characterization and transformation of plasmid pAA-1 found in an antarctic cryptoendolithic bacterium

• Published in: Canadian Journal of Microbiology
• Main Authors: Gliesche, Christian G., Jendrach, Marina, Peissl, Klaus, Siebert, Jörg, Hirsch, Peter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1996
• Subjects: Genetics; Molecular Biology; Applied Microbiology and Biotechnology; General Medicine; Immunology; Microbiology; Antarctic; McMurdo Dry Valleys; Paa; Linnaeus Terrace; Asgard Range; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1139/m96-077; http://www.nrcresearchpress.com/doi/pdf/10.1139/m96-077

Sixty-three bacterial isolates from antarctic sandstone samples (Linnaeus Terrace, Asgard Range, McMurdo Dry Valleys) were screened for the presence of plasmid DNA. Twenty-seven percent of all the isolates (mainly Gram-positives) harbored one or more plasmids of low molecular mass (1.1–16.3 kb). Strain AA-341 contained plasmid pAA-1 (2.9 kb), as demonstrated by agarose gel electrophoresis and restriction endonuclease digests. This plasmid conferred resistance to chromium and ampicillin. It was not conjugative, but it could be transferred by electroporation to chromium- and ampicillin-sensitive strains AA-330, AA-338, and E. coli HB101. A restriction map of pAA-1 was constructed with HindIII, SalI, ScaI, AvaII, EcoRI, PvuII, BamHI, and DraI. Electrotransfer of this plasmid from E. coli HB101(pAA-1) to strain AA-330 was demonstrated. By natural genetic transformation, plasmid pAA-1 could be transferred into the sensitive strain AA-334, which thereby became resistant to chromium and ampicillin. The importance of such processes for the colonization of stressed environments is discussed.Key words: Antarctica, cryptoendolithic bacteria, plasmids, resistance to chromium, natural transformation.