Fig 2.

(A) Physical map of pMX2. The unique restriction cleavage sites are indicated in the map. SSO, single-strand origin; DSO, double-strand origin; copG, transcriptional repressor protein gene; repB, replication initiation-termination protein gene; cat, chloramphenicol resistance gene; PmalX, malX promoter of S. suis. (B) Genomic Southern hybridization analysis to confirm introduction of pMX2 into M. plutonius. Genomic DNAs of ATCC 35311 and ATCC 35311 transformed with pMX2 were digested with EcoRI, separated by agarose gel electrophoresis, and probed with the cat probe. (C) β-Galactosidase activity of ATCC 35311 transformed with pMX2 and pMX2lacZ. In pMX2lacZ, the ribosomal binding site of the B. subtilis spoVG gene and the promoterless lacZ reporter gene of E. coli are located downstream of PmalX. Data were collected from six independent experiments. β-Galactosidase activity is expressed as Miller units (mean ± standard deviation). Differences in β-galactosidase activity were compared by the unpaired t test, using the Welch modification.