Disruption of Escherichia coli Amyloid-Integrated Biofilm Formation at the Air-Liquid Interface by a Polysorbate Surfactant

Langmuir (Impact Factor: 4.46). 12/2012; 29(3). DOI: 10.1021/la304710k
Source: PubMed


Functional amyloid fibers termed curli contribute to bacterial adhesion and biofilm formation in E. coli. We discovered that the nonionic surfactant Tween 20 inhibits biofilm formation by uropathogenic E. coli at the air-liquid interface, referred to as pellicle formation, and at the solid-liquid interface. At Tween 20 concentrations near and above the critical micelle concentration, the interfacial viscoelastic modulus is reduced to zero as cellular aggregates at the air-liquid interface are locally disconnected and eventually eliminated. Tween 20 does not inhibit the production of curli, but prevents curli-integrated film formation. Our results support a model in which the hydrophobic curli fibers associated with bacteria near the air-liquid interface require access to the gas phase to formed strong physical entanglements and to form a network that can support shear stress.

1 Follower
15 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Air-aqueous interfacial properties of four excipient proteins commonly used in immunoassay reagent formulations were studied with shear rheology and surface characterization methods. A Du Noüy ring geometry was utilized to quantify the elastic (G') and viscous (G″) shear moduli of protein interfacial networks and to probe the effect of several nonionic surfactants at various concentrations. Time sweep protocols of buffered protein solutions yielded G' in the range of 16mN/m for bovine serum albumin (BSA), 6mN/m for bovine gamma globulin (BGG), 7mN/m for Mouse IgG, and 0.9mN/m for sodium caseinate. G's were higher than G″s for a given protein. Effect of nonionic surfactants on G' of a protein was concentration dependent and the magnitude of protein displacement from the interface varied with Tween 20>Triton X-100>Triton X-405, with the exception of Mouse IgG. Degree of displacement of BSA from the interface by Tween 20 was approximately 66-fold greater than that of BGG whose displacement by Tween 20 was approximately 7-fold greater than that of Mouse IgG. Degree of displacement by Triton X-100 was comparable in case of studied proteins. Surface tension characterization suggests that the interfacial interactions between proteins and surfactants are driven not only by their surface activity but also by the network formation abilities of the proteins. Data presented here demonstrates a potential application of interfacial studies to sensitively identify discriminatory interactions between proteins and surfactants in immunoassay solutions.
    Colloids and surfaces B: Biointerfaces 09/2013; 113C:285-294. DOI:10.1016/j.colsurfb.2013.09.025 · 4.15 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Uropathogenic E. coli (UPEC) are the major causative agents of urinary tract infection and engage in a coordinated genetic and molecular cascade to colonize the urinary tract. Disrupting the assembly and/or function of virulence factors and bacterial biofilms has emerged as an attractive target for the development of new therapeutic strategies to prevent and treat urinary tract infection, particularly in the era of increasing antibiotic resistance among human pathogens. UPEC vary widely in their genetic and molecular phenotypes and more data are needed to understand the features that distinguish isolates as more or less virulent and as more robust biofilm formers or poor biofilm formers. Curli are extracellular functional amyloid fibers produced by E. coli that contribute to pathogenesis and influence the host response during urinary tract infection (UTI). We have examined the production of curli and curli-associated phenotypes including biofilm formation among a specific panel of human clinical UPEC that has been studied extensively in the mouse model of UTI. Motility, curli production, and curli-associated biofilm formation attached to plastic were the most prevalent behaviors, shared by most clinical isolates. We discuss these results in the context on the previously reported behavior and phenotypes of these isolates in the murine cystitis model in vivo.
    Biochemical and Biophysical Research Communications 11/2013; 443(2). DOI:10.1016/j.bbrc.2013.11.026 · 2.30 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Foam and emulsion stability has long been believed to correlate with the surface shear viscosity of the surfactant used to stabilize them. Many subtleties arise in interpreting surface shear viscosity measurements, however, and correlations do not necessarily indicate causation. Using a sensitive technique designed to excite purely surface shear deformations, we make the most sensitive and precise measurements to date of the surface shear viscosity of a variety of soluble surfactants, focusing on SDS in particular. Our measurements reveal the surface shear viscosity of SDS to be below the sensitivity limit of our technique, giving an upper bound of order 0.01 μN·s/m. This conflicts directly with almost all previous studies, which reported values up to 10(3)-10(4) times higher. Multiple control and complementary measurements confirm this result, including direct visualization of monolayer deformation, for SDS and a wide variety of soluble polymeric, ionic, and nonionic surfactants of high- and low-foaming character. No soluble, small-molecule surfactant was found to have a measurable surface shear viscosity, which seriously undermines most support for any correlation between foam stability and surface shear rheology of soluble surfactants.
    Proceedings of the National Academy of Sciences 02/2014; 111(10). DOI:10.1073/pnas.1315991111 · 9.67 Impact Factor
Show more