The Role of Extracellular Slime in Adhesion and Motility of Gliding Bacteria

The goal of this research is to characterize the role(s) of extracellular slime and of the cell surface in adhesion and motility of aquatic gliding bacteria. Initial biochemical and rheological analyses of the slime of Flexibacteria maritimus and several of its adhesion/motility mutants are described. A theoretical analysis of the function of slime in a motility mechanism based on travelling transverse undulating waves is described. Inconsistencies in adhesion of F. maritimus led us to measure the cell surface hydrophobicity of this and selected other gliding bacteria and determine how adhesion and motility are affected by critical surface energy (CSE) of the substratum. Wild-type gliders are relatively hydrophobic; they adhere most tenaciously to low CSE surfaces. For several gliding bacteria and their adhesion-deficient mutants and revertants, cell surface proteins that directly contact glass surfaces have been vectorially radio-iodinated. Distinct, complex labelling patterns are described. We also report the isolation of two marine gliding bacteria, one of which produces a high molecular weight inhibitor of adhesion of the second. Prepared in cooperation with Johns Hopkins University and the University of Edinburgh.