YdgG (TqsA) Controls Biofilm Formation in Escherichia coli K-12 through Autoinducer 2 Transport

ABSTRACT YdgG is an uncharacterized protein that is induced in Escherichia coli biofilms. Here it is shown that deletion of ydgG decreased extracellular and increased intracellular concentrations of autoinducer 2 (AI-2); hence, YdgG enhances transport of AI-2. Consistent with this hypothesis, deletion of ydgG resulted in a 7,000-fold increase in biofilm thickness and 574-fold increase in biomass in flow cells. Also consistent with the hypothesis, deletion of ydgG increased cell motility by increasing transcription of flagellar genes (genes induced by AI-2). By expressing ydgG in trans, the wild-type phenotypes for extracellular AI-2 activity, motility, and biofilm formation were restored. YdgG is also predicted to be a membrane-spanning protein that is conserved in many bacteria, and it influences resistance to several antimicrobials, including crystal violet and streptomycin (this phenotype could also be complemented). Deletion of ydgG also caused 31% of the bacterial chromosome to be differentially expressed in biofilms, as expected, since AI-2 controls hundreds of genes. YdgG was found to negatively modulate expression of flagellum- and motility-related genes, as well as other known products essential for biofilm formation, including operons for type 1 fimbriae, autotransporter protein Ag43, curli production, colanic acid production, and production of polysaccharide adhesin. Eighty genes not previously related to biofilm formation were also identified, including those that encode transport proteins (yihN and yihP), polysialic acid production (gutM and gutQ), CP4-57 prophage functions (yfjR and alpA), methionine biosynthesis (metR), biotin and thiamine biosynthesis (bioF and thiDFH), anaerobic metabolism (focB, hyfACDR, ttdA, and fumB), and proteins with unknown function (ybfG, yceO, yjhQ, and yjbE); 10 of these genes were verified through mutation to decrease biofilm formation by 40% or more (yfjR, bioF, yccW, yjbE, yceO, ttdA, fumB, yjiP, gutQ, and yihR). Hence, it appears YdgG controls the transport of the quorum-sensing signal AI-2, and so we suggest the gene name tqsA.

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YliH (BssR) and YceP (BssS) Regulate Escherichia coli K-12 Biofilm Formation by Influencing Cell Signaling

Applied and Environmental Microbiology ◽

10.1128/aem.72.4.2449-2459.2006 ◽

2006 ◽

Vol 72 (4) ◽

pp. 2449-2459 ◽

Cited By ~ 139

Author(s):

Joanna Domka ◽

Jintae Lee ◽

Thomas K. Wood

Keyword(s):

Escherichia Coli ◽

Amino Acids ◽

Cell Signaling ◽

Biofilm Formation ◽

Differentially Expressed ◽

Wild Type ◽

Autoinducer 2 ◽

Expression Of Genes ◽

Differential Gene ◽

K 12

ABSTRACT We previously discovered that yliH and yceP are induced in Escherichia coli biofilms (D. Ren, L. A. Bedzyk, S. M. Thomas, R. W. Ye, and T. K. Wood, Appl. Microbiol. Biotechnol. 64:515-524, 2004). Here, it is shown that deletion of yceP (b1060) and yliH (b0836) increases biofilm formation in continuous-flow chambers with minimal glucose medium by increasing biofilm mass (240- to 290-fold), surface coverage (16- to 31-fold), and mean thickness (2,800-fold). To determine the genetic basis of the increase in biofilm formation, we examined the differential gene expression profile in biofilms for both the mutants relative to the wild-type strain in rich medium with glucose and found that 372 to 882 genes were induced and that 76 to 337 were repressed consistently >2-fold (P ≤ 0.05). The increase in biofilm formation was related to differential expression of genes related to stress response (8 to 64 genes) for both mutants, including rpoS and sdiA. More importantly, 42 to 130 genes related to autoinducer 2 cell signaling were also differentially expressed, including gadAB and flgBCEGHIJLMN, as well as signaling through indole, since 17 to 26 indole-related genes were differentially expressed, including phoAER, gltBD, mtr (encodes protein for indole import), and acrEF (encodes proteins for indole export). Increased biofilm formation in the yliH and yceP mutants in LB supplemented with 0.2% glucose (LB glu) occurred through a reduction in extracellular and intracellular indole concentrations in both mutants (50- to 140-fold), and the addition of indole to the culture restored the wild-type biofilm phenotype; hence, indole represses biofilms. Additionally, both mutants regulate biofilms through quorum sensing, since deletion of either yliH or yceP increased extracellular autoinducer 2 concentrations 50-fold when grown in complex medium (most notably in the stationary phase). Both proteins are involved in motility regulation, since YliH (127 amino acids) and YceP (84 amino acids) repressed motility two to sevenfold (P ≤ 0.05) in LB, and YceP repressed motility sevenfold (P ≤ 0.05) in LB glu. Heightened motility in the yceP mutant occurred, due to increased transcription of the flagella and motility loci, including fliC, motA, and qseB (3- to 86-fold). We propose new names for these two loci: bssR for yliH and bssS for yceP, based on the phrase “regulator of biofilm through signal secretion.”

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Autoinducer 2 Controls Biofilm Formation in Escherichia coli through a Novel Motility Quorum-Sensing Regulator (MqsR, B3022)

Journal of Bacteriology ◽

10.1128/jb.188.1.305-316.2006 ◽

2006 ◽

Vol 188 (1) ◽

pp. 305-316 ◽

Cited By ~ 366

Author(s):

Andrés F. González Barrios ◽

Rongjun Zuo ◽

Yoshifumi Hashimoto ◽

Li Yang ◽

William E. Bentley ◽

...

Keyword(s):

Escherichia Coli ◽

Quorum Sensing ◽

Continuous Flow ◽

Biofilm Formation ◽

Type Strain ◽

Wild Type Strain ◽

Wild Type ◽

Flow Cells ◽

Autoinducer 2 ◽

K 12

ABSTRACT The cross-species bacterial communication signal autoinducer 2 (AI-2), produced by the purified enzymes Pfs (nucleosidase) and LuxS (terminal synthase) from S-adenosylhomocysteine, directly increased Escherichia coli biofilm mass 30-fold. Continuous-flow cells coupled with confocal microscopy corroborated these results by showing the addition of AI-2 significantly increased both biofilm mass and thickness and reduced the interstitial space between microcolonies. As expected, the addition of AI-2 to cells which lack the ability to transport AI-2 (lsr null mutant) failed to stimulate biofilm formation. Since the addition of AI-2 increased cell motility through enhanced transcription of five motility genes, we propose that AI-2 stimulates biofilm formation and alters its architecture by stimulating flagellar motion and motility. It was also found that the uncharacterized protein B3022 regulates this AI-2-mediated motility and biofilm phenotype through the two-component motility regulatory system QseBC. Deletion of b3022 abolished motility, which was restored by expressing b3022 in trans. Deletion of b3022 also decreased biofilm formation significantly, relative to the wild-type strain in three media (46 to 74%) in 96-well plates, as well as decreased biomass (8-fold) and substratum coverage (19-fold) in continuous-flow cells with minimal medium (growth rate not altered and biofilm restored by expressing b3022 in trans). Deleting b3022 changed the wild-type biofilm architecture from a thick (54-μm) complex structure to one that contained only a few microcolonies. B3022 positively regulates expression of qseBC, flhD, fliA, and motA, since deleting b3022 decreased their transcription by 61-, 25-, 2.4-, and 18-fold, respectively. Transcriptome analysis also revealed that B3022 induces crl (26-fold) and flhCD (8- to 27-fold). Adding AI-2 (6.4 μM) increased biofilm formation of wild-type K-12 MG1655 but not that of the isogenic b3022, qseBC, fliA, and motA mutants. Adding AI-2 also increased motA transcription for the wild-type strain but did not stimulate motA transcription for the b3022 and qseB mutants. Together, these results indicate AI-2 induces biofilm formation in E. coli through B3022, which then regulates QseBC and motility; hence, b3022 has been renamed the motility quorum-sensing regulator gene (the mqsR gene).

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Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

ISME Communications ◽

10.1038/s43705-021-00041-z ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Yue Xing ◽

Xiaoxi Kang ◽

Siwei Zhang ◽

Yujie Men

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Selective Pressure ◽

Fold Increase ◽

Streptomycin Resistance ◽

Evolutionary Stage ◽

Fitness Costs ◽

Evolutionary Trajectories ◽

K 12 ◽

Late Stages

AbstractTo explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5–6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

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Potentiation by L-cysteine of the bactericidal effect of hydrogen peroxide in Escherichia coli

Journal of Bacteriology ◽

10.1128/jb.152.1.81-88.1982 ◽

1982 ◽

Vol 152 (1) ◽

pp. 81-88

Author(s):

E H Berglin ◽

M B Edlund ◽

G K Nyberg ◽

J Carlsson

Keyword(s):

Escherichia Coli ◽

Hydrogen Peroxide ◽

Metal Ion ◽

Chelating Agent ◽

Fold Increase ◽

Bactericidal Effect ◽

Anaerobic Conditions ◽

Dna Breakage ◽

E Coli ◽

K 12

Under anaerobic conditions an exponentially growing culture of Escherichia coli K-12 was exposed to hydrogen peroxide in the presence of various compounds. Hydrogen peroxide (0.1 mM) together with 0.1 mM L-cysteine or L-cystine killed the organisms more rapidly than 10 mM hydrogen peroxide alone. The exposure of E. coli to hydrogen peroxide in the presence of L-cysteine inhibited some of the catalase. This inhibition, however, could not fully explain the 100-fold increase in hydrogen peroxide sensitivity of the organism in the presence of L-cysteine. Of other compounds tested only some thiols potentiated the bactericidal effect of hydrogen peroxide. These thiols were effective, however, only at concentrations significantly higher than 0.1 mM. The effect of L-cysteine and L-cystine could be annihilated by the metal ion chelating agent 2,2'-bipyridyl. DNA breakage in E. coli K-12 was demonstrated under conditions where the organisms were killed by hydrogen peroxide.

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

Microbiology ◽

10.1099/mic.0.000947 ◽

2020 ◽

Vol 166 (9) ◽

pp. 880-890 ◽

Cited By ~ 1

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.

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Evaluation of Changes Induced in the Probiotic Escherichia coli M17 Following Recurrent Exposure to Antimicrobials

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i29b31601 ◽

2021 ◽

pp. 158-167

Author(s):

M. J. A. Mbarga ◽

I. V. Podoprigora ◽

E. G. Volina ◽

A. V. Ermolaev ◽

L. A. Smolyakova

Keyword(s):

Escherichia Coli ◽

Growth Rate ◽

Silver Nanoparticles ◽

Biofilm Formation ◽

Fold Increase ◽

Bacterial Attachment ◽

Diffusion Method ◽

Cross Resistance ◽

Microdilution Method ◽

Similar Work

Introduction: It is already well known that the exposure of certain bacteria, pathogenic or not, to antimicrobials is likely to increase their virulence and induce the development of direct or cross resistance to antimicrobials, but there is almost no information available regarding probiotics. Aim: To assess the changes induced in susceptibility to antibiotics, biofilm formation, growth rate and relative pathogenicity in the probiotic Escherichia coli M17 (EC-M17) after long exposure to antimicrobials namely ampicillin, kanamycin, cefazolin and silver nanoparticles (AgNPs). Methods: After determining the minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of the 4 antimicrobials above-mentioned by the microdilution method, EC-M17 was exposed to increasing subinhibitory doses ranging from MIC/8 to MIC for 8 days. The susceptibility to antibiotics of the mutants obtained was assessed by the Kirby Bauer disc diffusion method, biofilm formation by the Congo red agar method and with crystal violet bacterial attachment assay, and relative pathogenicity was assessed using a Galleria melonella waxworm model. Results: Exposure to antimicrobials induces noticeable changes in EC-M17. The highest adaptation to antimicrobials was observed on AgNPs with 8-fold increase in MIC and 16-fold increase in MBC of AgNPs. EC-M17 exposed to ampicillin, kanamycin and silver nanoparticles became resistant to ampicillin, ceftazidime, ceftazidime/clavulanate and tetracycline while exposure to cefazolin induced a significant decrease in sensitivity to tetracycline and ampicillin and resistance to ceftazidime/clavulanate and ceftazidime. The strain exposed to ampicillin was the only one to produce more biofilm than the control strain and except the EC-M17 exposed to cefazolin, all other EC-M17 strains were more pathogenic on G. melonella model than the control. Conclusion: Data in this investigation suggest that repeated exposure of the probiotic EC-M17 to antimicrobials may induce changes in antimicrobials susceptibility, biofilm formation, growth rate, and relative pathogenicity. Therefore, as far as possible, the probiotic E. coli M17 should not be used in combination with antibiotics and further investigations are required to expand similar work on more probiotics in order to avoid resistance build-up which might be transmitted by horizontal transfer.

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Bioinformatic and Molecular Analysis of Inverse Autotransporters from Escherichia coli

mSphere ◽

10.1128/msphere.00572-19 ◽

2019 ◽

Vol 4 (4) ◽

Cited By ~ 3

Author(s):

Kelvin G. K. Goh ◽

Danilo G. Moriel ◽

Steven J. Hancock ◽

Minh-Duy Phan ◽

Mark A. Schembri

Keyword(s):

Escherichia Coli ◽

Cell Surface ◽

Biofilm Formation ◽

Secretion System ◽

Content Type ◽

E Coli ◽

Wide Range ◽

Type V Secretion ◽

K 12 ◽

Type V

ABSTRACT Proteins secreted by the type V secretion system possess multiple functions, including the capacity to mediate adhesion, aggregation, and biolfilm formation. The type V secretion system can be divided into five subclasses, one of which is the type Ve system. Proteins of the type Ve secretion system are also referred to as inverse autotransporters (IATs). In this study, we performed an in silico analysis of 126 completely sequenced Escherichia coli genomes available in the NCBI database and identified several distinct IAT-encoding gene families whose distribution varied throughout the E. coli phylogeny. The genes included three characterized IATs (intimin, fdeC, and yeeJ) and four uncharacterized IATs (here named iatA, iatB, iatC, and iatD). The four iat genes were cloned from the completely sequenced environmental E. coli strain SMS-3-5 and characterized. Three of these IAT proteins (IatB, IatC, and IatD) were expressed at the cell surface and possessed the capacity to mediate biofilm formation in a recombinant E. coli K-12 strain. Further analysis of the iatB gene, which showed a unique association with extraintestinal E. coli strains, suggested that its regulation is controlled by the LeuO global regulator. Overall, this study provides new data describing the prevalence, sequence variation, domain structure, function, and regulation of IATs found in E. coli. IMPORTANCE Escherichia coli is one of the most prevalent facultative anaerobes of the human gut. E. coli normally exists as a harmless commensal but can also cause disease following the acquisition of genes that enhance its pathogenicity. Adhesion is an important first step in colonization of the host and is mediated by an array of cell surface components. In E. coli, these include a family of adhesins secreted by the type V secretion system. Here, we identified and characterized new proteins from an emerging subclass of the type V secretion system known as the inverse autotransporters (IATs). We found that IAT-encoding genes are present in a wide range of strains and showed that three novel IATs were localized on the E. coli cell surface and mediated biofilm formation. Overall, this study provides new insight into the prevalence, function, and regulation of IATs in E. coli.

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Nickel Promotes Biofilm Formation by Escherichia coli K-12 Strains That Produce Curli

Applied and Environmental Microbiology ◽

10.1128/aem.02171-08 ◽

2009 ◽

Vol 75 (6) ◽

pp. 1723-1733 ◽

Cited By ~ 40

Author(s):

Claire Perrin ◽

Romain Briandet ◽

Gregory Jubelin ◽

Philippe Lejeune ◽

Marie-Andrée Mandrand-Berthelot ◽

...

Keyword(s):

Escherichia Coli ◽

Biofilm Formation ◽

Molecular Mechanisms ◽

Selective Advantage ◽

Bacterial Survival ◽

Toxic Compounds ◽

E Coli ◽

Transcriptional Effect ◽

K 12 ◽

Encoding Genes

ABSTRACT The survival of bacteria exposed to toxic compounds is a multifactorial phenomenon, involving well-known molecular mechanisms of resistance but also less-well-understood mechanisms of tolerance that need to be clarified. In particular, the contribution of biofilm formation to survival in the presence of toxic compounds, such as nickel, was investigated in this study. We found that a subinhibitory concentration of nickel leads Escherichia coli bacteria to change their lifestyle, developing biofilm structures rather than growing as free-floating cells. Interestingly, whereas nickel and magnesium both alter the global cell surface charge, only nickel promotes biofilm formation in our system. Genetic evidence indicates that biofilm formation induced by nickel is mediated by the transcriptional induction of the adhesive curli-encoding genes. Biofilm formation induced by nickel does not rely on efflux mechanisms using the RcnA pump, as these require a higher concentration of nickel to be activated. Our results demonstrate that the nickel-induced biofilm formation in E. coli is an adaptational process, occurring through a transcriptional effect on genes coding for adherence structures. The biofilm lifestyle is obviously a selective advantage in the presence of nickel, but the means by which it improves bacterial survival needs to be investigated.

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