YmdB inhibits biofilm formation in an RNase III-independent manner. (A) Effect of the presence or absence of RNase III on YmdB-mediated inhibition of biofilm formation. Biofilm formation by BW25113 (rnc+) or KSK001 (rnc14) cells with or without plasmid [pCA24N (−gfp) or ASKA-ymdB (−)] was measured using cells grown at 37°C for 24 h in LB medium containing IPTG (0.1 mM final) Mean values (n = 10, p = 0.05) are shown. “Relative biofilm formation” for KSK001 and ASKA-ymdB (in BW25113 or KSK001) was determined relative to the biofilm formation by each control set (BW25113 or pCA24N; set to 1.0). (B) Expression levels of YmdB. The expression of YmdB (His-YmdB) in total cell lysates (from A) was detected by immunoblotting with 6xHis Epitope Tag antibody as described in Methods. S1 protein level was used as loading control.