Affiliation:
1. Laboratoire de Génétique Moléculaire des Microorganismes et des Interactions Cellulaires, CNRS UMR 5577, Institut National des Sciences Appliquées de Lyon, 69621 Villeurbanne, France
Abstract
ABSTRACT
To get further information on bacterial surface sensing and biofilm-dependent regulation of gene expression in
Escherichia coli
K-12, random insertion mutagenesis with Mu dX, a mini-Mu carrying the promoterless
lacZ
gene, was performed with an
ompR234
adherent strain, and a simple screen was developed to assess changes in gene expression in biofilm cells versus planktonic cells. This screen revealed that major changes in the pattern of gene expression occur during biofilm development: the transcription of 38% of the genes was affected within biofilms. Different cell functions were more expressed in sessile bacteria: the OmpC porin, the high-affinity transport system of glycine betaine (encoded by the
proU
operon), the colanic acid exopolysaccharide (
wca
locus, formerly called
cps
), tripeptidase T (
pepT
), and the nickel high-affinity transport system (
nikA
). On the other hand, the syntheses of flagellin (
fliC
) and of a putative protein of 92 amino acids (
f92
) were both reduced in biofilms. Such a genetic reprogramming of gene expression in biofilms seems to result from changes in multiple environmental physicochemical conditions. In this work, we show that bacteria within biofilms encounter higher-osmolarity conditions, greater oxygen limitation, and higher cell density than in the liquid phase.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
430 articles.
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