Pdl1 increases TcdB release into the supernatant.

<p>(<b>A</b>) Western blot analysis of culture supernatants (sup), and cellular membrane (mem) and soluble fractions, which includes cell cytosol and periplasm fractions (sol). Preparations from 24 h cultures of <i>E. coli</i> containing c1AH10 with transposon insertions into either the pWEB vector backbone (CVI-wt) or the <i>pdl1</i> gene (<i>pdl1</i> KO-mutant). X = marker and Vec = whole cell pWEB negative vector control. The presence or absence of Tcd is visualised using the antibody raised against the C-terminus of the B-subunit. Protein from an induced clone containing a B and C-subunit expression construct (pBC+) is included as a positive control. (<b>B</b>) An anti-β-Lactamase western blot was performed to ensure no contamination of soluble material in the membrane fraction. (<b>C</b>) An anti-SecG western blot was performed to ensure no contamination of membrane material in the soluble fraction.