Figure 4

Effect of the OprB1 overexpression on the profile of outer membrane proteins and cell lysis. A and B. SDS-PAGE of outer membrane protein preparations stained with Coomassie Blue. Representative results of the P. putida PaW85 (wt), oprB1-deficient (B1) as well as OprB1-overexpressing strains PaWoprB1-tacB1 (B1tacB1) and PaWcolR-oprB1-tacB1 (RB1tacB1) are presented. OM proteins were extracted from 24-hour-old populations of bacteria grown on solid minimal medium with either 0.2% glucose or gluconate. OM proteins presented in panel B have been purified from the cells which were grown in the presence of 0.5 mM IPTG. Plus (+) marks above the lanes designate a particular carbon source added to the growth medium. Arrow indicates location of OprB1. C. Quantification of cell lysis by the unmasked β-galactosidase assay. Bacteria were grown for 24 hours on solid 0.2% glucose (glc) or 0.2% gluconate (gn) minimal medium containing 1 mM phenol (+phe). For the induction of OprB1 0.5 mM IPTG was used. Data (mean ± standard deviation) of at least three independent determinations are presented.