Figure 2.

Determination of phenotypes in cell morphology and purified flagella caused by deletion of fcpB. (A) The L. biflexa fcpB⁻ mutant is deficient in its ability to form hook- and spiral-shaped ends, which are characteristic of wild-type cells. Cells were examined by dark-field microscopy with a 100X oil-immersion objective. (B) Periplasmic filaments purified from the L. biflexa fcpB⁻ mutant lack the super-coiled morphology, which is characteristic of purified wild-type flagellar filaments when examined in vitro. Complementation of fcpB⁻ mutant restores wild-type morphology and coiled flagellar filament structure. Bar scales for negative staining images are 200 nm for WT and fcpB^−/+ complemented strain, and 500 nm for fcpB⁻ mutant.