Regulation of biofilm formation in Escherichia coli K12: Effect of mutations in the genes HNS, STRA, LON, and RPON

Belik, A. Yu.; Tarasova, N. N.; Khmel, I. A.

doi:10.3103/s0891416808040010

Cited by 12 publications

(13 citation statements)

References 25 publications

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“…The role of 54 in regulating numerous biological properties, including those related to virulence, has been well documented for a variety of bacterial species (3,10,21,42,49,51,52,55,58,59). However, its role in E. faecalis has been limited to observations made regarding its contribution to sensitivity to class IIa bacteriocins through the regulation of sugar PTSs (9,13,22).…”

Section: Discussionmentioning

confidence: 99%

“…In the major food-borne pathogen Listeria monocytogenes, 54 is essential for its osmotolerance potential (41) and is responsible for mesentericin sensitivity (14, 41), whereas in Pseudomonas aeruginosa, 54 influences the activity of isocitrate lyase (21), alginate biosynthesis (6), and pilin and flagellin production, in addition to several other virulence determinants (44). Sigma 54 also regulates biofilm formation, enterocyte effacement, acid tolerance, flagellar biosynthesis, and several other processes in Escherichia coli (3,49,60).…”

mentioning

confidence: 99%

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Deletion of σ ⁵⁴ ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Iyer

Hancock

2012

J Bacteriol

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Transcription initiation is a critical step in bacterial gene regulation and is often controlled by transcription regulators. The alternate sigma factor ( 54 ) is one such regulator that facilitates activator-dependent transcription initiation and thus modulates the expression of a variety of genes involved in metabolism and pathogenesis in bacteria. This study describes the role of 54 in the nosocomial pathogen Enterococcus faecalis. Biofilm formation is one of the important pathogenic mechanisms of E. faecalis, as it elevates the organism's potential to cause surgical site and urinary tract infections. Lysis of bacterial cells within the population contributes to biofilm formation by providing extracellular DNA (eDNA) as a key component of the biofilm matrix. Deletion of rpoN rendered E. faecalis resistant to autolysis, which in turn impaired eDNA release. Despite the significant reduction in eDNA levels compared to the parental strain, the rpoN mutant formed more robust biofilms as observed using laser scanning confocal microscopy and Comstat analysis, indicating and emphasizing the presence of other matrix components. Initial adherence to a polystyrene surface was also enhanced in the mutant. Proteinase K treatment at early stages of biofilm development significantly reduced the accumulation of biofilm by the rpoN mutant. In conclusion, our data indicate that other factors in addition to eDNA might contribute to the overall composition of the enterococcal biofilm and that the regulatory role of 54 governs the nature and composition of the biofilm matrix.A s opportunistic pathogens, enterococci are the third leading cause of hospital-acquired or associated infections, as they are responsible for 11.2% of surgical site infections (SSI), 14.9% of urinary tract infections (UTI), and 16% of reported bloodstream infections (25). The ability to form a biofilm is an important aspect of the lifestyle of the organism, as biofilm formation is thought to be a property associated with the establishment of SSI and UTI (34), both of which can serve as foci to establish bloodstream infections. Biofilms are aggregates of bacteria that are covered in exoploymer matrix and are more resistant to antibiotics than their planktonic counterparts (15,26). In several bacterial species, nucleic acids, polysaccharides, proteins, and lipids constitute the exopolymer matrix (19). The components of the biofilm matrix form a physical barrier that enhances the inaccessibility of the biofilm cells to antibiotics and the immune system, thereby making the infection difficult to eradicate (33). Extracellular DNA (eDNA) serves as an important biofilm matrix component in several microbial model systems, including but not limited to Neisseria meningitidis, Listeria monocytogenes, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, and Staphylococcus epidermidis (2,23,29,32,36,47,48,54). The expression of the two secreted E. faecalis proteases, gelatinase and serine protease, is regulated in a quorum-dependent manner by the Fsr re...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Deletion of σ ⁵⁴ ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Iyer

Hancock

2012

J Bacteriol

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“…However, in earlier studies, it was reported that mutant strains of RpoN in E. coli K12 and Enterococcus faecalis also formed biofilms [57, 58]. RpoS mutant strain was also observed to form biofilm in E. coli ZK126 stains as well as in P. aeroginosa [59, 60].…”

Section: Discussionmentioning

confidence: 99%

“…The RpoN mutant strain of B. burgdorferi formed a biofilm which was 22% less in size than the wild-type 297. Previously, it was reported that the deletion of RpoN gene in E. coli K12 strains increased the biofilm formation by 40–60%, and also in E. faecalis , the RpoN mutant strain was observed to form robust biofilms [57, 58]. In this study, we showed that RpoS mutant strain of B. burgdorferi had 16% reduction in the biofilm formation compared to wild-type similar to the deletion of RpoS gene in E. coli ZK126 which reduced the biofilm size by 50% [59].…”

Section: Discussionmentioning

confidence: 99%

Effect of RpoN, RpoS and LuxS pathways on the biofilm formation and antibiotIc sensitivity of Borrelia burgdorferi

Sapi¹,

Theophilus²,

Pham³

et al. 2016

EuJMI

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Borrelia burgdorferi, the causative agent of Lyme disease, is capable of forming biofilm in vivo and in vitro, a structure well known for its resistance to antimicrobial agents. For the formation of biofilm, signaling processes are required to communicate with the surrounding environment such as it was shown for the RpoN–RpoS alternative sigma factor and for the LuxS quorum-sensing pathways. Therefore, in this study, the wild-type B. burgdorferi and different mutant strains lacking RpoN, RpoS, and LuxS genes were studied for their growth characteristic and development of biofilm structures and markers as well as for their antibiotic sensitivity. Our results showed that all three mutants formed small, loosely formed aggregates, which expressed previously identified Borrelia biofilm markers such as alginate, extracellular DNA, and calcium. All three mutants had significantly different sensitivity to doxycyline in the early log phase spirochete cultures; however, in the biofilm rich stationary cultures, only LuxS mutant showed increased sensitivity to doxycyline compared to the wild-type strain. Our findings indicate that all three mutants have some effect on Borrelia biofilm, but the most dramatic effect was found with LuxS mutant, suggesting that the quorum-sensing pathway plays an important role of Borrelia biofilm formation and antibiotic sensitivity.

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“…In addition, it is required by Burkholderia cenocepacia to form biofilm and to survive inside macrophage [61]. On the other hand, in E. coli s54 regulates biofilm formation and flagelar synthesis amongst other processes [62,63]. Also, s54 regulates initial attachment of Enterococcus faecalis to its substrate and the composition of the biofilm matrix [64].…”

Section: Signal Transduction Mechanismsmentioning

confidence: 97%

Response to copper of Acidithiobacillus ferrooxidans ATCC 23270 grown in elemental sulfur

Almárcegui

Navarro

Paradela

et al. 2014

Research in Microbiology

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Regulation of biofilm formation in Escherichia coli K12: Effect of mutations in the genes HNS, STRA, LON, and RPON

Cited by 12 publications

References 25 publications

Deletion of σ ⁵⁴ ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Deletion of σ ⁵⁴ ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Effect of RpoN, RpoS and LuxS pathways on the biofilm formation and antibiotIc sensitivity of Borrelia burgdorferi

Response to copper of Acidithiobacillus ferrooxidans ATCC 23270 grown in elemental sulfur

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Regulation of biofilm formation in Escherichia coli K12: Effect of mutations in the genes HNS, STRA, LON, and RPON

Cited by 12 publications

References 25 publications

Deletion of σ 54 ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Deletion of σ 54 ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Effect of RpoN, RpoS and LuxS pathways on the biofilm formation and antibiotIc sensitivity of Borrelia burgdorferi

Response to copper of Acidithiobacillus ferrooxidans ATCC 23270 grown in elemental sulfur

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Deletion of σ ⁵⁴ ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis

Deletion of σ ⁵⁴ ( rpoN ) Alters the Rate of Autolysis and Biofilm Formation in Enterococcus faecalis