Natural horizontal transfer of a naphthalene dioxygenase gene between bacteria native to a coal tar-contaminated field site.

摘要: Horizontal transfer of genes responsible for pollutant biodegradation may play a key role in the evolution bacterial populations and adaptation microbial communities to environmental contaminants. However, field evidence horizontal gene between microorganisms has traditionally been very difficult obtain. In this study, sequences 16S rRNA naphthalene dioxygenase iron-sulfur protein (nahAc) nine naphthalene-degrading bacteria isolated from coal tar waste-contaminated site, as well bacterium contaminated site Washington state two archetypal strains, were compared. Seven strains study had single nahAc allele, whereas differed by much 7.9%. No alleles identical those although predominant allele was closely related that Pseudomonas putida NCIB 9816-4, British Isles. one site-derived strain. Lack phylogenetic congruence indicates relatively recent situ occurred, possibly direct or indirect consequence contamination. Alkaline lysis plasmid preparations pulsed-field gel electrophoresis have revealed presence plasmids ranging size 70 88 kb all isolates. Southern hybridizations with 407-bp probe suggested is borne isolates but one, strain subsurface sediment 400 m upstream source other state, appears be chromosomally located. addition, isolate carry on both chromosome plasmid. Within group showed distributed different sizes chromosome. This suggests modification after effected transposons. catabolic significant acclimation pollutants.