Schematic representation of the construction of pJW241 (a) and pJW245 (b). pTB6ori is a replication origin for B. longum, and ColE1ori (high-copy) and pSC101ori
(low-copy) are replication origins for E. coli. Ampr and Spr indicate the ampicillin- and spectinomycin-resistance genes, respectively. The small arrows indicate the primers
used for PCR. See Section 2 for details