|Marcus, Ian - University Of California|
|Cook, Kimberly - Kim|
|Opot, Stephen - University Of California|
|Walker, Sharon - University Of California|
Submitted to: Journal of Environmental Monitoring
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/25/2012
Publication Date: 3/1/2012
Publication URL: http://handle.nal.usda.gov/10113/55938
Citation: Marcus, I.M., Bolster, C.H., Cook, K.L., Opot, S.R., Walker, S.L. 2012. Impact of growth conditions on transport behavior of E. coli. Journal of Environmental Monitoring. 14:984-991.
Interpretive Summary: Contamination from fecal matter is the leading cause of impairment of potable water sources in the U.S. and Escherichia coli is the most commonly identified fecal indicator bacteria (FIB) originating from agricultural runoff. Given the importance of E. coli to water quality concerns, a significant amount of research has been devoted to understanding the factors controlling the movement of this microorganism in the environment. Much of this research, however, has utilized highly idealized conditions including the media in which the bacteria are grown in. This study seeks to address this limitation of previous research by comparing surface characteristics and transport behavior of E. coli grown in standard laboratory growth media with E. coli grown in manure extract. In general, cells grown in manure extract were more hydrophobic, had a more negative zeta potential, had lower amounts of surface macromolecules, and had greater transport potential than isolates grown in standard laboratory growth media. This study shows the need to consider growth conditions when studying E. coli to better mimic the environmental stresses that bacteria undergo in the natural environment. This approach could lead to a better understanding of the behavior of manure-derived bacteria in aquatic and terrestrial environments.
Technical Abstract: The aim of this investigation is to determine the effect that growth solution has on cell surface properties and transport behavior of eleven E. coli isolates through saturated porous media. The two growth solutions used were a standard laboratory growth medium (LB) and a dairy manure extract solution. In general, cells grown in manure extract were more hydrophobic, had a more negative zeta potential, had lower amounts of surface macromolecules, and had lower attachment efficiencies than isolates grown in LB. An inverse relationship between the natural log of zeta potential and the attachment efficiency of the isolates for the cells grown in LB media was the only statistically significant correlation observed between transport behavior and cell characteristics of the isolates. This study shows the need to consider growth conditions when studying bacteria to better mimic the environmental stresses that bacteria undergo in the natural environment. This approach could lead to a better understanding of the behavior of manure-derived bacteria in aquatic and terrestrial environments.