Each of the Arthrobacter strains examined contained a putative parB gene however, ofthe three plasmids in Arthrobacter strain FB24 only one plasmid had a putative parB gene. Putative parA partitioning genes werefound in all of the plasmids. Genes with similarity to a relaxase, coupling protein, and various components of a type IV secretion system wereidentied on each plasmid it appears that three dierent systems may be present. All eight plasmids contained a putative conjugationsystem. Iteron likesequences were identied on some of the plasmids however, no genes with obvious similarity to known replicationsequences such as an origin of replication, or rep genes were identied. In this study, we compared eight plasmids from ve Arthrobacterstrains in order to identify putative core maintenance genes for replication, segregation, and conjugation. The role of plasmids in the dis-semination of genes for antibiotic resistance (Tayloret al., 2004), metal resistance (Borremans et al.,2001 Lebrun et al., 1994 Nucifora et al., 1989),Communicated by Dawn Fieldĭespite the prevalence of Arthrobacter in the environment little is known about their plasmids, or the capacity of Arth-robacter plasmids to mediate horizontal gene transfer. Quent to account for adaptive evolution bacteriaare thought to use the vast, phylogenetically diversegene pool available to them by HGT (Levin andBergstrom, 2000). Horizontal gene transfer (HGT), by transduc-tion, conjugation, or natural transformation, isone of the driving forces of bacterial adaptationand evolution with signicant numbers of bacterialgenomes showing evidence of HGT (Gogarten and Nakatsu).Īvailable online at Plasmid 59 (2008) 70147-619X/$ - see front matter 2008 Elsevier Inc. However, most of the studied plasmids residewithin a few restricted bacterial clades nearly 70%of the sequences in the Plasmid Genome Database Chro-mosomal recombination in bacteria is too infre-Īnd for organic compound catabolism have beenextensively studied (Sayler et al., 1990 Top et al.,2000). Townsend, 2005 Smalla and Sobecky, 2002). Keywords: Arthrobacter Plasmids Conjugation Partitioning
Received, revised 18 October 2007Available online 31 January 2008