title: Characterization of Halomonas sp. ZM3 isolated from the Zelazny Most post-flotation waste reservoir, with a special focus on its mobile DNA.
abstract: BACKGROUND
  Halomonas sp. ZM3 was isolated from Zelazny Most post-flotation mineral waste repository (Poland), which is highly contaminated with heavy metals and various organic compounds. Mobile DNA of the strain (i.e. plasmids and transposons) were analyzed in order to identify genetic information enabling adaptation of the bacterium to the harsh environmental conditions.
  
  
  RESULTS
  The analysis revealed that ZM3 carries plasmid pZM3H1 (31,370 bp), whose replication system may be considered as an archetype of a novel subgroup of IncU-like replicons. pZM3H1 is a narrow host range, mobilizable plasmid (encodes a relaxase of the MOBV family) containing mercury resistance operon (mer) and czcD genes (mediate resistance to zinc and cobalt), which are part of a large truncated Tn3 family transposon. Further analysis demonstrated that the phenotypes determined by the pZM3H1 resistance cassette are highly dependent on the host strain. In another strand of the study, the trap plasmid pMAT1 was employed to identify functional transposable elements of Halomonas sp. ZM3. Using the sacB positive selection strategy two insertion sequences were identified: ISHsp1 - representing IS5 group of IS5 family and ISHsp2 - a distinct member of the IS630 family.
  
  
  CONCLUSIONS
  This study provides the first detailed description of mobile DNA in a member of the family Halomonadaceae. The identified IncU plasmid pZM3H1 confers resistance phenotypes enabling adaptation of the host strain to the Zelazny Most environment. The extended comparative analysis has shed light on the distribution of related IncU plasmids among bacteria, which, in many cases, reflects the frequency and direction of horizontal gene transfer events. Our results also identify plasmid-encoded modules, which may form the basis of novel shuttle vectors, specific for this group of halophilic bacteria.
authors.affiliation: University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Bacterial Genetics, Miecznikowa 1, Warsaw, 02-096, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Dziewit
authors.forename: Adam
authors.initials: A
authors.lastname: Pyzik
authors.forename: Renata
authors.initials: R
authors.lastname: Matlakowska
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Baj
authors.forename: Magdalena
authors.initials: M
authors.lastname: Szuplewska
authors.forename: Dariusz
authors.initials: D
authors.lastname: Bartosik
mesh_terms: D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics*; D004783:Environmental Microbiology; D020632:Halomonas / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D020071:Interspersed Repetitive Sequences; D008969:Molecular Sequence Data; D010957:Plasmids / Q000032:analysis; D011044:Poland; D017422:Sequence Analysis, DNA; D062611:Solid Waste
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D062611:Solid Waste