[Potential vectors for molecular cloning in Brevibacterium flavum].

Construction of the shuttle cloning vectors for Escherichia coli-Brevibacterium flavum system is described. Expression of the Sp/Sm resistance determinant derived from the Corynebacterium plasmid pCG4 was registered in Escherichia coli cells. The genetic determinant for Sp/Sm resistance was shown to be located in a 2.2 kb PstI-SphI fragment by the deletion analysis mapping in Escherichia coli cells. Using Escherichia coli as a host we cloned the unique 0.8 kb EcoRI-EcoRI fragment of Brevibacterium flavum bacteriophage phi BSh6 in the plasmids with dual replication origins. Blocking of the shuttle vector transfer to Brevibacterium flavum by the insertion of bacteriophage phi BSh6 DNA was observed. The deletion of entire phage fragment or a specific part of it made it possible introduction of plasmids harboured by Escherichia coli cells into Brevibacterium flavum. A potential vector for homologous DNA cloning in Brevibacterium flavum was constructed.