Role of yifO, agaB, and atoS in Escherichia coli biofilm formation and stress response
Abstract
In nature, bacteria exist predominantly as a surface adherent community referred
to as a biofilm, which differs phenotypically from planktonic cells. Alterations in
phenotypic expression are essential not only for transition through the various stages of
biofilm formation, but also for maintenance. In this study, we sought to elicit differences
in phenotypic expression in E. coli biofilms, as well as to characterize several mutants to
determine if expression is essential for biofilm formation. Of the numerous differentially
expressed genes identified by gene array analysis, yjfO, agaB, and atoS were selected for
further characterization Results from both epifluorescence microscopy and microtiter
assays confirmed that all mutant strains displayed a reduction in biofilm formation in
comparison to the wild-type E. coli. Additionally, we sought to elicit differences in the viability of both planktonic and biofilm cells following exposure to hydrogen peroxide,
pH shifts and elevated temperature Planktonically grown mutant strains exhibited a
decreased viability following exposure to acidic pH and hydrogen peroxide, whereas the
atoS mutant exhibited an increased viability at elevated temperatures compared to that of
the wild-type. Exposure of four day biofilms to hydrogen peroxide resulted in an
insignificant decrease in biofilm mass for all strains, whereas exposure to acidic pH
resulted in a decreased biofilm for only the wild-type and the yjfO mutant. Overall, our
results suggest that mutations affecting yjfO, agaB, or atoS lead to a decreased ability to
form a biofilm and a decreased ability to survive exposure to hydrogen peroxide and
acidic pH when grown planktonically.
Citation
Weber, M. M. (2007). Role of yifO, agaB, and atoS in Escherichia coli biofilm formation and stress response (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.Download
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