Behaviors and Energy Source ofMycoplasma gallisepticumGliding

Abstract

ABSTRACTMycoplasma gallisepticum, an avian-pathogenic bacterium, glides on host tissue surfaces by using a common motility system withMycoplasma pneumoniae. In the present study, we observed and analyzed the gliding behaviors ofM. gallisepticumin detail by using optical microscopes.M. gallisepticumglided at a speed of 0.27 ± 0.09 µm/s with directional changes relative to the cell axis of 0.6 ± 44.6 degrees/5 s without the rolling of the cell body. To examine the effects of viscosity on gliding, we analyzed the gliding behaviors under viscous environments. The gliding speed was constant in various concentrations of methylcellulose but was affected by Ficoll. To investigate the relationship between binding and gliding, we analyzed the inhibitory effects of sialyllactose on binding and gliding. The binding and gliding speed sigmoidally decreased with sialyllactose concentration, indicating the cooperative binding of the cell. To determine the direct energy source of gliding, we used a membrane-permeabilized ghost model. We permeabilizedM. gallisepticumcells with Triton X-100 or Triton X-100 containing ATP and analyzed the gliding of permeabilized cells. The cells permeabilized with Triton X-100 did not show gliding; in contrast, the cells permeabilized with Triton X-100 containing ATP showed gliding at a speed of 0.014 ± 0.007 μm/s. These results indicate that the direct energy source for the gliding motility ofM. gallisepticumis ATP.IMPORTANCEMycoplasmas, the smallest bacteria, are parasitic and occasionally commensal.Mycoplasma gallisepticumis related to human pathogenicMycoplasmas—Mycoplasma pneumoniaeandMycoplasma genitalium—which causes so-called ‘walking pneumonia’ and non-gonococcal urethritis, respectively. TheseMycoplasmastrap sialylated oligosaccharides, which are common targets among influenza viruses, on host trachea or urinary tract surfaces and glide to enlarge the infected areas. Interestingly, this gliding motility is not related to other bacterial motilities or eukaryotic motilities. Here, we quantitatively analyze cell behaviors in gliding and clarify the direct energy source. The results provide clues for elucidating this unique motility mechanism.