Effects of outer membrane protein TolC on the transport of Escherichia coli within saturated quartz sands. Environ Sci Technol 2013 Jun 04;47(11):5720-8
Date
05/01/2013Pubmed ID
23627691Pubmed Central ID
PMC3705718DOI
10.1021/es400292xScopus ID
2-s2.0-84878639861 (requires institutional sign-in at Scopus site) 29 CitationsAbstract
The outer membrane protein (OMP) TolC is the cell surface component of several drug efflux pumps that are responsible for bacterial resistance against a variety of antibiotics. In this research, we investigated the effects of OMP TolC on E. coli transport within saturated sands through column experiments using a wild-type E. coli K12 strain (with OMP TolC), as well as the corresponding transposon mutant (tolC::kan) and the markerless deletion mutant (ΔtolC). Our results showed OMP TolC could significantly enhance the transport of E. coli when the ionic strength was 20 mM NaCl or higher. The deposition rate coefficients for the wild-type E. coli strain (with OMP TolC) was usually >50% lower than those of the tolC-negative mutants. The measurements of contact angles using three probe liquids suggested that TolC altered the surface tension components of E. coli cells and lead to lower Hamaker constants for the cell-water-sand system. The interaction energy calculations using the extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory suggested that the deposition of the E. coli cell primarily occurred at the secondary energy minimum. The depth of the secondary energy minimum increased with ionic strength, and was greater for the TolC-deletion strains under high ionic strength conditions. Overall, the transport behavior of three E. coli strains within saturated sands could be explained by the XDLVO calculations. Results from this research suggested that antibiotic resistant bacteria expressing OMP TolC could spread more widely within sandy aquifers.
Author List
Feriancikova L, Bardy SL, Wang L, Li J, Xu SAuthor
Sonia L. Bardy in the Biological Sciences department at University of Wisconsin - MilwaukeeMESH terms used to index this publication - Major topics in bold
Bacterial Outer Membrane ProteinsBiological Transport
Escherichia coli K12
Escherichia coli Proteins
Groundwater
Membrane Transport Proteins
Osmolar Concentration
Quartz
Silicon Dioxide
