Figure 6: Correlation of ITL to DNA ladder bands in agarose gel electrophoresis. (A) Electrophoresis of plasmid pBR322 DNA treated with E. coli topoisomerases. Lane 1, linear pBR322 DNA marker (0.3 µg); Lane 2, supercoiled DNA marker (0.3 µg); Lane 3, supercoiled DNA (0.3 µg) treated with E. coli topoisomerase I (1U); Lane 4, supercoiled DNA (0.3 µg) treated with E. coli topoisomerase IV (1U). OC, open circular DNA; L, linear DNA; SC, supercoiled DNA. (B) Electrophoresis of plasmid pBR322 DNA (0.3 µg) isolated from different strains of E. coli . Lane 1, from E. coli DM800; lane 2, from E. coli SD108; lane 3, from E. coli HB101. Chloroquine was included in the agarose gel at 3µg/ml. (C) AFM image of pBR322 DNA treated withE. coli topoisomerase I. (D) AFM image of pBR322 DNA treated with E. coli topoisomerase IV. (E) AFM image of pBR322 DNA isolated from E.coli HB101. (F) AFM image of pBR322 DNA isolated from E. coli DM800.