title: In situ characterization of differences in the viscoelastic response of individual gram-negative and gram-positive bacterial cells.
abstract: We used a novel atomic force microscopy (AFM)-based technique to compare the local viscoelastic properties of individual gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacterial cells. We found that the viscoelastic properties of the bacterial cells are well described by a three-component mechanical model that combines an instantaneous elastic response and a delayed elastic response. These experiments have allowed us to investigate the relationship between the viscoelastic properties and the structure and composition of the cell envelope. In addition, this is the first report in which the mechanical role of Lpp, the major peptidoglycan-associated lipoprotein and one of the most abundant outer membrane proteins in E. coli cells, has been quantified. We expect that our findings will be helpful in increasing the understanding of the structure-property relationships of bacterial cell envelopes.
authors: Department of Physics, University of Guelph, Guelph, Ontario, Canada.
authors: Virginia
authors: V
authors: Vadillo-Rodriguez
authors: Sarah R
authors: SR
authors: Schooling
authors: John R
authors: JR
authors: Dutcher
mesh_terms: D001412:Bacillus subtilis / Q000737:chemistry / Q000502:physiology*; D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D002473:Cell Wall / Q000737:chemistry; D004548:Elasticity; D004926:Escherichia coli / Q000737:chemistry / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000032:analysis; D008074:Lipoproteins / Q000032:analysis; D018625:Microscopy, Atomic Force / Q000379:methods; D008962:Models, Theoretical; D014783:Viscosity
chemical_list: D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C099932:Lpp protein, E coli