Molecular Architecture and Assembly Principles of Vibrio cholerae Biofilms

Abstract

In their natural environment, microbes organize into communities held together by an extracellular matrix composed of polysaccharides and proteins. We developed an in vivo labeling strategy to allow the extracellular matrix of developing biofilms to be visualized with conventional and super-resolution light microscopy. Vibrio cholerae biofilms displayed three distinct levels of spatial organization: cells, clusters of cells, and collections of clusters. Multiresolution imaging of living V. cholerae biofilms revealed the complementary architectural roles of the four essential matrix constituents: RbmA provided cell-cell adhesion, Bap1 allowed the developing biofilm to adhere to surfaces, and heterogeneous mixtures of Vibrio polysaccharide (VPS), RbmC, and Bap1 formed dynamic, flexible and ordered envelopes that encased the cell clusters.

Extracellular matrix structure governs invasion resistance in bacterial biofilms

“…This result was observed both in the presence and in the absence of invading cells, and it is consistent with previous reports documenting that V. cholerae biofilms lacking RbmA are structurally weaker than biofilms possessing the full complement of matrix proteins (Fong et al, 2006;Absalon et al, 2011;Berk et al, 2012;Giglio et al, 2013;Maestre-Reyna et al, 2013).…”

“…Structural studies suggest that RbmA binds motherdaughter cell pairs together, linking them to polysaccharide components of the extracellular matrix (Giglio et al, 2013;Maestre-Reyna et al, 2013). Relative to biofilms expressing the full complement of matrix components, biofilms lacking RbmA exhibit poor sub-cluster coherence (Absalon et al, 2011;Berk et al, 2012). We hypothesized that the absence of RbmA could render V. cholerae biofilms susceptible to invasion by planktonic cells.…”

“…Biofilm-dwelling cells of Rugose V. cholerae are tightly packed (Berk et al, 2012), a property attributed to the secreted matrix protein RbmA (Moorthy and Watnick, 2005;Fong et al, 2006;Fong and Yildiz, 2007), which is produced rapidly following surface adhesion and becomes distributed throughout mature V. cholerae biofilms (Absalon et al, 2011;Berk et al, 2012). Structural studies suggest that RbmA binds motherdaughter cell pairs together, linking them to polysaccharide components of the extracellular matrix (Giglio et al, 2013;Maestre-Reyna et al, 2013).…”

“…For matrix protein localization experiments, the Rugose strain produced a RbmA 3xFLAG C-terminal fusion (Berk et al, 2012). This strain is referred to as R-RbmA-FLAG.…”

The role of cell-surface interactions in bacterial initial adhesion and consequent biofilm formation on nanofiltration/reverse osmosis membranes

“…In one recent study, it was shown that Vibrio cholerae biofilm formation is characterized by changes in matrix composition during early stages biofilm growth, in which an envelope made up of different types of polysaccharides and proteins enclose cell clusters and was found to be capable of stretching and expanding to accommodate cell growth. [50]. These observations have not been addressed in the context of membrane biofouling, but could be important considering the composition of feedwater with respect to potential early colonisers.…”