rRNA sequence-based homologous recombination. Schematic presentation of double homologous recombination between the pM2 and the host ribosomal 16S-23S region. The binding sites of the primers 97ar/kmup and K1/E9F used to confirm the chromosomal integration of the constructs are indicated by arrows. KmR; kanamycin-resistance (npt I); strepR: streptomycin resistance; gfp: gfpuv-gene (enhanced GFP) with native promoter; 16S: 16S rRNA sequence (1 kb) of Acinetobacter sp; 23S: 23S rRNA sequence (1,258 bp) of Psychrobacter sp. Figures are not to scale.