Force and flexibility of flailing myxobacteria.
Myxococcus xanthus is a common Gram-negative bacterium that moves by a process called gliding motility. In myxobacteria, two distinct mechanisms for gliding have been discovered. S-type motility requires the extension, attachment, and retraction of type IV pili. The other mechanism, designated as A-type motility, may be driven by the secretion and swelling of slime; however, experiments to confirm or refute this model are still lacking and the force exerted by this mechanism has not been measured. A previously published experiment found that when an M. xanthus cell became stuck at one end, the cell underwent flailing motions. Based on this experiment, I propose an elastic model that can estimate the force produced by the A-motility engine and the bending modulus of a single myxobacterial cell. The model estimates a bending modulus of 3 x 10(-14) erg cm and a force between 50-150 pN. This force is comparable to that predicted by slime extrusion, and the bending modulus is 30-fold smaller than that measured in Bacillus subtilis. This model suggests experiments that can further quantify this process.
Wolgemuth
Charles W
CW
Department of Cell Biology, University of Connecticut Health Center, Farmington, USA. cwolgemuth@uchc.edu
D002448:Cell Adhesion / Q000502:physiology; D003198:Computer Simulation; D004548:Elasticity; D010861:Fimbriae, Bacterial / Q000502:physiology* / Q000648:ultrastructure; D008954:Models, Biological; D020409:Molecular Motor Proteins / Q000502:physiology*; D009038:Motion; D009231:Myxococcales / Q000166:cytology / Q000502:physiology*; D013314:Stress, Mechanical
D020409:Molecular Motor Proteins