FIG 1.

Lack of FlgO results in reduced motility. (A) Motility of cells in soft agar. Two-microliter aliquots of overnight cultures of each strain was spotted onto a 0.25% soft agar VPG plate containing 2.5 μg/ml chloramphenicol and 0.02% (wt/vol) l-arabinose, and the plate was incubated at 30°C for 7 h. Deletion of flgO from the strain KK148 resulted in reduced motility, and ectopic expression of FlgO fused with a hexa-histidine tag at the C terminus (FlgO-His₆) from the arabinose-inducible plasmid pTSK128 restored motility (protein expression was confirmed [B]). VIO5 is the wild-type strain for polar flagellar motility; KK148 is multipolar flagellar strain and the parent of NMB337. The plasmid pBAD33 was used as the empty vector control. (B) Immunoblot analysis. Whole-cell lysates were separated by SDS-PAGE and transferred onto the PVDF membrane, and His-tagged proteins were detected by an anti-His tag antibody. The FlgO-His₆ protein was detected at the size equivalent to its mature form (indicated as the filled arrow). Experiments were conducted 3 times, and the typical results are shown here.