Fig. 5

Deletion of drug resistant gene MXAN_2566 in M.xanthus DK1622. a Schematic diagram to delete MXAN_2566 in DK1622 Firstly, pBJ113-2566, which contains two homologous arms, was integrated into the genome of DK1622 by kanamycin selection, and the second crossover occurred by galactose-addition to the culture to obtain strain DK-2566. b Identification of double crossover strains DK-2566 by agarose gel electrophoresis of PCR product. Lanes 1 and 2 are the bands from wild type DK1622 (1.1 kb), lanes 3, 4, 5, and 6 show 0.6 kb bands representing the double crossover strain DK-2566 using primer p21 and p24. c Growth curves of M. xanthus wild type and mutant strains in CTT liquid medium with or without Cm. DK1622Cm indicated the DK1622 already adapted in Cm-containing CTT + Cm liquid medium, accordingly the growth curve of DK1622Cm/CTT + Cm is similar to that of DK1622 in CTT liquid medium. Fresh DK1622 wild type would stay 6 days dormancy in CTT + Cm liquid medium, which has a dormant phase. While drug resistance gene deleted strain DK-2566 stays 9 days dormancy, which is beyond the colony growth time (7 days) on CTT agar plate. 5D. Chromatograms of the 0.6-kb PCR product DNA sequence. The PCR primers P21, P24 as the sequencing primers were used to confirm the deleted fragment. The nucleotide position of the flanking regions between the Restriction enzyme site XbaI (TCTAGA) were marked on the peak of chromatograms