title: Role of Cell Appendages in Initial Attachment and Stability of E. coli on Silica Monitored by Nondestructive TIRF Microscopy.
abstract: Total internal reflection fluorescence (TIRF) microscopy was used to investigate initial attachment and stability of wild-type, curli-deficient (ΔcsgA), flagella-deficient (ΔflhDC), and type-1 fimbriae-deficient (Δfim) mutant E. coli strains. Suspended bacteria were injected into a flow cell where they deposited on a silica coverslip, and images were acquired over a 2 min period. TIRF microscope image analysis revealed that curli- and flagella-deficient mutants attached closer to the surface and required a longer time to find their equilibrium position (i.e., bond maturation) as compared to the wild-type and fimbriae-deficient mutants. Analysis of the change in bacterial surface area over the 2 min period also indicated that curli- and flagella-deficient mutants have less initial stability than the wild-type and fimbriae-deficient mutants, evidenced by their fluctuating position at equilibrium. TIRF observations at the microscopic level were complemented macroscopically using quartz crystal microbalance with dissipation (QCM-D) and sand-packed column experiments, which support the distinctive behavior observed at the microscopic scale. For each mutant strain, as fluorescence intensity increased in TIRF, the negative frequency shift in QCM-D (related to the attached mass of bacteria) also increased. Packed-column experiments indicated that curli- and flagella-deficient mutants exhibited a characteristically different attachment behavior and more retention as compared to the wild-type and fimbriae-deficient strains. This study utilized a new approach to understand bacterial attachment/detachment and provides new insights into the role of various appendages on initial attachment and stability.
authors.affiliation: Department of Chemical Engineering, McGill University , Montreal, QC, Canada.|Department of Chemical Engineering, University of Leuven , Leuven, Belgium.
authors.forename: Kerwin K W
authors.initials: KKW
authors.lastname: Wong
authors.affiliation: Department of Chemical Engineering, McGill University , Montreal, QC, Canada.
authors.forename: Adam L J
authors.initials: ALJ
authors.lastname: Olsson
authors.affiliation: Department of Chemical Engineering, McGill University , Montreal, QC, Canada.
authors.forename: Bahareh
authors.initials: B
authors.lastname: Asadishad
authors.affiliation: Department of Chemical Engineering, University of Leuven , Leuven, Belgium.|Faculty of Engineering and the Built Environment, Tshwane University of Technology , Pretoria, South Africa.
authors.forename: Bart
authors.initials: B
authors.lastname: van der Bruggen
authors.affiliation: Department of Chemical Engineering, McGill University , Montreal, QC, Canada.
authors.forename: Nathalie
authors.identifier: 0000-0002-1546-3441
authors.initials: N
authors.lastname: Tufenkji