Plasmids of alkaline-utilising Arthrobacter

Representatives of the genus Arthrobacter were screened for the presence of plasmids. Four alkane-utilising strains showed at least one plasmid and were tested for resistance to antibiotics and heavy metal salts, citrate and alkane-utilisation and production of bacteriocin. All the strains of Arthrobacter screened were resistant to at least 60 mM arsenate and in addition, the four plasmid carrying strains were also resistant to 20 mM arsenite. Heat- and chemical-induced loss of resistance to these salts and the ability to utilise alkanes or citrate, did not lead to the concomitant loss of any plasmids. A small plasmid of 5.5 kb (pSP1) was found in three representatives. A detailed restriction map of pSP1 suggests it could be useful as a potential cloning vector in this group of organisms.