title: Plasmid diversity in arctic strains of Psychrobacter spp.
abstract: Six strains of Psychrobacter spp. isolated from guano of little auks collected on Spitsbergen island (Arctic) carried nine plasmids that were fully sequenced. These replicons (ranging in size from 2917 to 14924 bp) contained either repA (ColE2-type) or repB (iteron-type) replication systems of a relatively narrow host range, limited to Psychrobacter spp. All but one of the plasmids carried predicted mobilization for conjugal transfer systems, encoding relaxases of the MOBQ, MOBV or MOBP families. The plasmids also contained diverse additional genetic load, including a type II restriction-modification system and a gene encoding a putative subunit C of alkyl hydroperoxide reductase (AhpC)-an antioxidant enzyme and major scavenger of reactive oxygen species. Detailed comparative sequence analyses, extended to all plasmids identified so far in psychrophilic bacteria, distinguished groups of the most ubiquitous replicons, which play a key role in horizontal gene transfer in cold environments.
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland. ldziewit@biol.uw.edu.pl
authors.forename: Lukasz
authors.initials: L
authors.lastname: Dziewit
authors.forename: Adrian
authors.initials: A
authors.lastname: Cegielski
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Romaniuk
authors.forename: Witold
authors.initials: W
authors.lastname: Uhrynowski
authors.forename: Antoni
authors.initials: A
authors.lastname: Szych
authors.forename: Pawel
authors.initials: P
authors.lastname: Niesiobedzki
authors.forename: Magdalena J
authors.initials: MJ
authors.lastname: Zmuda-Baranowska
authors.forename: Marek K
authors.initials: MK
authors.lastname: Zdanowski
authors.forename: Dariusz
authors.initials: D
authors.lastname: Bartosik
mesh_terms: D001110:Arctic Regions; D001426:Bacterial Proteins / Q000235:genetics; D003227:Conjugation, Genetic / Q000235:genetics; D015280:DNA Restriction-Modification Enzymes / Q000235:genetics; D014644:Genetic Variation; D054464:Peroxiredoxins / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D044096:Psychrobacter / Q000235:genetics*; D012093:Replicon / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D015280:DNA Restriction-Modification Enzymes; D054464:Peroxiredoxins