Open AccessEffect of growth conditions on poly‐ N ‐acetylglucosamine expression and biofilm formation in Escherichia coli
Author(s) -
Cerca Nuno,
Jefferson Kimberly K.
Publication year - 2008
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2008.01142.x
Subject(s) - biofilm , escherichia coli , microbiology and biotechnology , operon , mutant , staphylococcus aureus , biology , staphylococcus epidermidis , gene expression , chemistry , bacteria , biochemistry , gene , genetics
Escherichia coli contains a four‐gene operon, pgaABCD , which encodes the proteins necessary for the synthesis of polymeric N ‐acetylglucosamine, or PGA. Poly‐ N ‐acetyl‐glucosamine was first described in Staphylococcus aureus and Staphylococcus epidermidis and was found to have important roles in biofilm formation and immune evasion. PGA also plays a role in biofilm formation in E. coli , but its role in immune evasion has not been thoroughly studied. We previously reported that E. coli PGA cross‐reacts with an opsonic‐antibody raised against S. aureus PNAG and this is the basis for an ongoing investigation regarding the development of a vaccine against both pathogens. In this paper we investigated pga expression in wild type and csrA or nhaR deletion mutant strains during different growth phases and temperatures, and in response to chemical stimuli using a pga promoter‐reporter fusion construct, real‐time reverse transcriptase‐PCR, immunoblotting, and biofilm assays. Expression of pga and polysaccharide synthesis were induced by glucose, NaCl, and ethanol, but only glucose augmented biofilm formation. The regulatory factor NhaR was required for NaCl‐induced pga expression, whereas the effects of glucose and ethanol were independent of CsrA and NhaR.