Genome map and integration site of phage Sf101. (a) The Sf101 genome is shown with a scale in bp. orfs are represented by arrows oriented in the direction of transcription. Putative functional modules are indicated above the arrows. Black knobs below the scale depict the Rho-independent terminators and the attachment site of the phage (attP) is indicated with a blue vertical arrow. (b) Schematic representation of phage Sf101 integrative recombination where attP on the phage genome recombines with the attB within sbcB gene of S. flexneri chromosome to form the two junction’s recombination sites attL and attR. Arrows P1 (sbcB-dwn-att-Fwd) and P2 (Orf22-up-Rev) on the map indicate the primers used in the PCR.