Beyond the Chromosome: The Prevalence of Unique Extra-Chromosomal Bacteriophages with Integrated Virulence Genes in Pathogenic Staphylococcus aureus
Figure 4
VISA extra-chromosomal DNA contains circular ExPФ's.
Extra-chromosomal DNA of VISA strains NRS19 (ΦBU01, A and B) and NRS26 (C and D) was treated with or without Plasmid-Safe linear DNase treatment (DNase-linear, +/−), separated on a 0.7% agarose gel (B and D), and visualized with SYBR Safe DNA stain. DNA bands separated on the gel were transferred to a nylon membrane and analyzed by Southern blot using probes based on bacteriophage genes (A and C). Probes were generated by PCR amplification of genes located in bacteriophage phage DNA using primers sets bdu211/bdu212 for NRS19 (ΦBU01) and bdu215/bdu216 for NRS26 (Table S2 in File S1). MRSA strain NRS70 (70, A and C) was used as a negative control in the Southern blot.