Frozen motion of gliding bacteria outlines inherent features of the motility apparatus

摘要

High-resolution data of actively gliding wild-type bacteria of four different species and of four different gliding mutants of Myxococcus xanthus were obtained from scanning electron micrographs. By shock freezing and freeze drying, motility-associated surface patterns could be fixed and consequently distinct intermediate states of motion could be observed for the first time. It is shown that these topographic patterns are immediately lost when gliding motility is stopped by blocking the respiratory chain with potassium cyanide or sodium azide. From the surface topography, the mode of action of the gliding apparatus of all four bacterial species examined can be described as a twisted circularly closed ‘band’. During gliding, groups of nodes of the supertwisted apparatus show evidence of travelling like waves along the trichomes. However, the spacing between the nodes is not constant but varies within a certain range. This indicates that they are flexibly modulated as a consequence of the gliding state of the individual trichome.