scholarly journals YcfR (BhsA) Influences Escherichia coli Biofilm Formation through Stress Response and Surface Hydrophobicity

2007 ◽  
Vol 189 (8) ◽  
pp. 3051-3062 ◽  
Author(s):  
Xue-Song Zhang ◽  
Rodolfo García-Contreras ◽  
Thomas K. Wood
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Stress Responses ◽  
Biofilm Formation ◽  
Outer Membrane Proteins ◽  
Cell Aggregation ◽  
Surface Hydrophobicity ◽  
Receptor Protein ◽  
Signal Molecules ◽  
K 12

ABSTRACT DNA microarrays revealed that expression of ycfR, which encodes a putative outer membrane protein, is significantly induced in Escherichia coli biofilms and is also induced by several stress conditions. We show that deletion of ycfR increased biofilm formation fivefold in the presence of glucose; the glucose effect was corroborated by showing binding of the cyclic AMP receptor protein to the ycfR promoter. It appears that YcfR is a multiple stress resistance protein, since deleting ycfR also rendered the cell more sensitive to acid, heat treatment, hydrogen peroxide, and cadmium. Increased biofilm formation through YcfR due to stress appears to be the result of decreasing indole synthesis, since a mutation in the tnaA gene encoding tryptophanase prevented enhanced biofilm formation upon stress and adding indole prevented enhanced biofilm formation upon stress. Deleting ycfR also affected outer membrane proteins and converted the cell from hydrophilic to hydrophobic, as well as increased cell aggregation fourfold. YcfR seems to be involved in the regulation of E. coli K-12 biofilm formation by decreasing cell aggregation and cell surface adhesion, by influencing the concentration of signal molecules, and by interfering with stress responses. Based on our findings, we propose that this locus be named bhsA, for influencing biofilm through hydrophobicity and stress response.

scholarly journals Roles of pgaABCD Genes in Synthesis, Modification, and Export of the Escherichia coli Biofilm Adhesin Poly-β-1,6-N-Acetyl-d-Glucosamine

2008 ◽  
Vol 190 (10) ◽  
pp. 3670-3680 ◽  
Author(s):  
Yoshikane Itoh ◽  
John D. Rice ◽  
Carlos Goller ◽  
Archana Pannuri ◽  
Jeannette Taylor ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Outer Membrane ◽  
Protein Interactions ◽  
Biofilm Formation ◽  
Cell Envelope ◽  
Outer Membrane Proteins ◽  
Attachment Site ◽  
Covalent Modification ◽  
Carbohydrate Binding ◽  
K 12

ABSTRACT The linear homopolymer poly-β-1,6-N-acetyl-d-glucosamine (β-1,6-GlcNAc; PGA) serves as an adhesin for the maintenance of biofilm structural stability in diverse eubacteria. Its function in Escherichia coli K-12 requires the gene products of the pgaABCD operon, all of which are necessary for biofilm formation. PgaC is an apparent glycosyltransferase that is required for PGA synthesis. Using a monoclonal antibody directed against E. coli PGA, we now demonstrate that PgaD is also needed for PGA formation. The deletion of genes for the predicted outer membrane proteins PgaA and PgaB did not prevent PGA synthesis but did block its export, as shown by the results of immunoelectron microscopy (IEM) and antibody adsorption assays. IEM also revealed a conditional localization of PGA at the cell poles, the initial attachment site for biofilm formation. PgaA contains a predicted β-barrel porin and a superhelical domain containing tetratricopeptide repeats, which may mediate protein-protein interactions, implying that it forms the outer membrane secretin for PGA. PgaB contains predicted carbohydrate binding and polysaccharide N-deacetylase domains. The overexpression of pgaB increased the primary amine content (glucosamine) of PGA. Site-directed mutations targeting the N-deacetylase catalytic activity of PgaB blocked PGA export and biofilm formation, implying that N-deacetylation promotes PGA export through the PgaA porin. The results of previous studies indicated that N-deacetylation of β-1,6-GlcNAc in Staphylococcus epidermidis by the PgaB homolog, IcaB, anchors it to the cell surface. The deletion of icaB resulted in release of β-1,6-GlcNAc into the growth medium. Thus, covalent modification of β-1,6-GlcNAc by N-deacetylation serves distinct biological functions in gram-negative and gram-positive species, dictated by cell envelope differences.

scholarly journals Roles of YcfR in Biofilm Formation in Salmonella Typhimurium ATCC 14028

2019 ◽  
Vol 32 (6) ◽  
pp. 708-716 ◽  
Author(s):  
Seul I Kim ◽  
Hyunjin Yoon
Keyword(s):  
Outer Membrane ◽  
Stress Responses ◽  
Salmonella Enterica ◽  
Biofilm Formation ◽  
Structural Changes ◽  
Outer Membrane Proteins ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Enteric Pathogens ◽  
Farm Produce

An increasing number of foodborne diseases are currently attributable to farm produce contaminated with enteric pathogens such as Salmonella enterica. Recent studies have shown that a variety of enteric pathogens are able to colonize plant surfaces by forming biofilms and thereby persist for long periods, which can subsequently lead to human infections. Therefore, biofilm formation by enteric pathogens on plants poses a risk to human health. Here, we deciphered the roles of YcfR in biofilm formation by Salmonella enterica. YcfR is a putative outer membrane protein associated with bacterial stress responses. The lack of YcfR facilitated the formation of multicellular aggregates on cabbage leaves as well as glass surfaces while reducing bacterial motility. ycfR deletion caused extensive structural alterations in the outer membrane, primarily in lipopolysaccharides, outer membrane proteins, cellulose, and curli fimbria, thereby increasing cell surface hydrophobicity. However, the absence of YcfR rendered Salmonella susceptible to stressful treatments, despite the increased multicellular aggregation. These results suggest that YcfR is an essential constituent of Salmonella outer membrane architecture and its absence may cause multifaceted structural changes, thereby compromising bacterial envelope integrity. In this context, YcfR may be further exploited as a potential target for controlling Salmonella persistence on plants.

scholarly journals Novel regulators of the csgD gene encoding the master regulator of biofilm formation in Escherichia coli K-12

Microbiology ◽  
2020 ◽  
Vol 166 (9) ◽  
pp. 880-890 ◽  
Author(s):  
Hiroshi Ogasawara ◽  
Toshiyuki Ishizuka ◽  
Shuhei Hotta ◽  
Michiko Aoki ◽  
Tomohiro Shimada ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Cell Aggregation ◽  
Master Regulator ◽  
Gene Encoding ◽  
Content Type ◽  
Promoter Probe ◽  
K 12 ◽  
Specific Environmental Condition

Under stressful conditions, Escherichia coli forms biofilm for survival by sensing a variety of environmental conditions. CsgD, the master regulator of biofilm formation, controls cell aggregation by directly regulating the synthesis of Curli fimbriae. In agreement of its regulatory role, as many as 14 transcription factors (TFs) have so far been identified to participate in regulation of the csgD promoter, each monitoring a specific environmental condition or factor. In order to identify the whole set of TFs involved in this typical multi-factor promoter, we performed in this study ‘promoter-specific transcription-factor’ (PS-TF) screening in vitro using a set of 198 purified TFs (145 TFs with known functions and 53 hitherto uncharacterized TFs). A total of 48 TFs with strong binding to the csgD promoter probe were identified, including 35 known TFs and 13 uncharacterized TFs, referred to as Y-TFs. As an attempt to search for novel regulators, in this study we first analysed a total of seven Y-TFs, including YbiH, YdcI, YhjC, YiaJ, YiaU, YjgJ and YjiR. After analysis of curli fimbriae formation, LacZ-reporter assay, Northern-blot analysis and biofilm formation assay, we identified at least two novel regulators, repressor YiaJ (renamed PlaR) and activator YhjC (renamed RcdB), of the csgD promoter.

scholarly journals Iron-regulated outer membrane proteins of Escherichia coli K-12 and mechanism of action of catechol-substituted cephalosporins.

1988 ◽  
Vol 32 (12) ◽  
pp. 1879-1886 ◽  
Author(s):  
N A Curtis ◽  
R L Eisenstadt ◽  
S J East ◽  
R J Cornford ◽  
L A Walker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Mechanism Of Action ◽  
Outer Membrane Proteins ◽  
K 12
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