6.11 Type IX Secretion System


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    Type IX Secretion System

    Other bacteria use different machinery to move over surfaces. Flavobacterium johnsoniae like this cell use a type IX secretion system to secrete adhesive filaments. These filaments move on a helical track around the cell, and thereby the cell moves forward on a surface (see Howard Berg’s website for a video of the cells moving). The power for this gliding movement is thought to come from rotary motors anchored in the cell wall that propel the adhesive filaments along their track in a rack-and-pinion fashion, but we still do not understand the mechanism in detail.