Schematic representation of the <i>E. coli</i>-bifidobacterial shuttle vectors pDM1 and pDM2.

<p>pDM1 is a derivative of pAM5 where the tetracycline resistance gene has been replaced with the spectinomycin resistance cassette. pDM2 is a derivative of the plasmid pDG7 where the spectinomycin resistance cassette was cloned in the unique EcoR1 and HindIII sites of pDG7.</p>