Affiliation:
1. Department of Biology, Southwest Texas State University, San Marcos, Texas 78666-4616
Abstract
ABSTRACT
Slow growth has been hypothesized to be an essential aspect of bacterial physiology within biofilms. In order to test this hypothesis, we employed two strains of
Escherichia coli
, ZK126 (Δ
lacZ rpoS
+
) and its isogenic Δ
rpoS
derivative, ZK1000. These strains were grown at two rates (0.033 and 0.0083 h
−1
) in a glucose-limited chemostat which was coupled either to a modified Robbins device containing plugs of silicone rubber urinary catheter material or to a glass flow cell. The presence or absence of
rpoS
did not significantly affect planktonic growth of
E. coli
. In contrast, biofilm cell density in the
rpoS
mutant strain (ZK1000), as measured by determining the number of CFU per square centimeter, was reduced by 50% (
P
< 0.05). Deletion of
rpoS
caused differences in biofilm cell arrangement, as seen by scanning confocal laser microscopy. In reporter gene experiments, similar levels of
rpoS
expression were seen in chemostat-grown planktonic and biofilm populations at a growth rate of 0.033 h
−1
. Overall, these studies suggest that
rpoS
is important for biofilm physiology.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
138 articles.
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