CHARACTERIZATION OF A SMALL PLASMID FROM DESULFOVIBRIO-DESULFURICANS AND ITS USE FOR SHUTTLE VECTOR CONSTRUCTION

A 2.3-kb plasmid present in about 20 copies per genome was identified in extracts of Desulfovibrio desulfuricans G100A and designated pBG1. It appears to be unable to replicate in Escherichia coli. Although com posite plasmids of pBG1 inserted into pTZ18U are stable in E. coli, fe w if any pBG1-specific transcripts are detectable. The plasmid sequenc e reveals several features typical of the origin of replication of non -ColE1 enterobacterial plasmids as well as several potential open read ing frames. This small replicon has been shown to support the replicat ion of recombinant plasmids in D. desulfuricans G100A and Desulfovibri o fructosovorans. A conjugable shuttle vector has been constructed.