title: Identification of miniature plasmids in psychrophilic Arctic bacteria of the genus Variovorax.
abstract: The Svalbard archipelago (Spitsbergen Island) is the northernmost landmass in the European Arctic and has a variety of small- and medium-sized glaciers. The plasmidome of eleven psychrophilic strains of Variovorax spp. isolated from the ice surface of Hans and Werenskiold Glaciers of Spitsbergen Island, was defined. This analysis revealed the presence of six plasmids whose nucleotide sequences have been determined. Four of them, exhibiting high reciprocal sequence similarity, possess unique structures, since their genomes lack any recognized genes. These miniature replicons, not exceeding 1 kb in size, include pHW69V1 (746 bp), which is the smallest autonomous replicon so far identified in free-living bacteria. The miniature plasmids share no similarity with known sequences present in the databases. In silico and experimental analyses identified conserved DNA regions essential for the initiation of replication of these replicons.
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Ciok
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.affiliation: Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland.
authors.forename: Jakub
authors.initials: J
authors.lastname: Grzesiak
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
authors.forename: Karol
authors.initials: K
authors.lastname: Budzik
authors.affiliation: Department of Microbiology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Oczapowskiego 1A, 10-719 Olsztyn, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Gorniak
authors.affiliation: Department of Antarctic Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland.
authors.forename: Marek K
authors.initials: MK
authors.lastname: Zdanowski
authors.affiliation: Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
authors.forename: Dariusz
authors.initials: D
authors.lastname: Bartosik
mesh_terms: D001110:Arctic Regions; D001483:Base Sequence; D003080:Cold Temperature; D042621:Comamonadaceae / Q000235:genetics*; D046448:Ice Cover / Q000382:microbiology; D008969:Molecular Sequence Data; D010957:Plasmids / Q000145:classification / Q000235:genetics*; D012093:Replicon / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013538:Svalbard
keywords: Arctic; Variovorax; glacier; miniature plasmid; psychrophile; replication system