AVS 46th International Symposium
    Biomaterial Interfaces Group Wednesday Sessions
       Session BI-WeM

Paper BI-WeM11
The Effect of Lipopolysaccharide Structure and Composition on Microbial Cell Adhesion

Wednesday, October 27, 1999, 11:40 am, Room 613/614

Session: Cell Solid-Surface Interactions
Presenter: S. Kim, University of Arizona
Authors: S. Kim, University of Arizona
J. Curry, University of Arizona
Correspondent: Click to Email
Lipopolysaccharide (LPS), the main component of the outer membrane of Gram negative bacteria, consists of a lipid component, termed lipid A, that anchors the LPS in the outer membrane, a sugar core, and a variable O-specific polysaccharide chain. Whenever a bacterium approaches a surface, LPS predominantly mediates the interaction because of its inherent location on the cell surface. Varying size and structure of LPS molecule depending on bacterial strain appears to be an important determinant of the overall charge and hydrophobic character of the cell surface. Furthermore, some workers have shown that change in its chemical composition or pattern lead to a dramatic change in its biological activity. Those facts suggest that studying adhesion as a function of LPS structure and chemical composition may help to better understand the mechanisms of bacterial adhesion. The overall goal of our research is to understand at the molecular scale how the structure and composition of the LPS affects bacterial adhesion and biological activity by direct force measurement using the Surface Forces Apparatus (SFA). Specifically, we will measure the force of interaction and adhesion between two hydrophilic (bare mica) and hydrophobic (surfactant coated) surfaces in the presence of LPS molecules at different environmental conditions (i.e. temperature, pH, ionic strength). Samples used in this study will be several rough mutant LPS (R-form) molecules of which structures are well characterized. Along with the knowledge of their structure and chemical composition, the complete force profile will allow us to better predict adhesive properties of several different types of bacteria. This work will be very meaningful for research in many areas where microbial adhesion is important, for instance, biofilm formation and microbial transport in porous media.