scholarly journals Establishment of Optogenetic Modulation of cAMP for Analyzing Growth, Biofilm Formation, and Virulence Pathways of Bacteria Using a Light-Gated Cyclase

2020 ◽  
Vol 10 (16) ◽  
pp. 5535
Author(s):  
Manish Singh Kaushik ◽  
Swaroop Ranjan Pati ◽  
Shivanika Soni ◽  
Ayushi Mishra ◽  
Kumari Sushmita ◽  
...  
Keyword(s):  
Blue Light ◽  
Biofilm Formation ◽  
Research Work ◽  
Adenosine Monophosphate ◽  
Camp Signaling ◽  
Light Illumination ◽  
Dependent Manner ◽  
Regulatory Pathways ◽  
Bacterial Physiology ◽  
E Coli

In bacteria, cyclic adenosine monophosphate (cAMP) signaling plays an essential regulatory role whose modulation via optogenetic tools would provide researchers an immense opportunity to control biological processes simply by illumination. The cAMP signaling in bacteria is a complex network of regulatory pathways, which utilizes distinct proteomic resources under different nutrient environments. We established an optogenetic modulation of cAMP and studied important cellular process of growth, biofilm formation, and virulence in the model bacterium E. coli using a light-gated adenylate cyclase (LgAC) from Beggiatoa sp. Blue light-induced activation of LgAC elevated the cAMP level in a blue light-dependent manner in E. coli. Quantitative proteomics revealed a decrease in the level of certain proteins governing growth (PTS, Adk, AckA, GlnA, and EFP), biofilm formation (IhfA, flagellin, YajQ, YeaG, and HlfC), and virulence (ClpP, YebC, KatE, BtuE, and Zur) in E. coli cells expressing LgAC upon blue light illumination. This optogenetic modulation of cAMP would be useful for deciphering cAMP-associated host–pathogen signaling of bacterial systems. Proteome knowledge established by this research work would also be useful for the scientific community while adapting LgAC-based optogenetic modulation for studying other relevant cAMP-driven bacterial physiology (e.g., energy metabolism). The systematic utilization of the established method and more extensively designed experiments regarding bacterial growth, biofilm, survival, and virulence might provide a road map for the identification of new targets for developing novel antibacterial drugs.

Escherichia coli tol and rcs genes participate in the complex network affecting curli synthesis

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2487-2497 ◽  
Author(s):  
Anne Vianney ◽  
Grégory Jubelin ◽  
Sophie Renault ◽  
Corine Dorel ◽  
Philippe Lejeune ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Membrane Integrity ◽  
Regulatory Proteins ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Dominant Effect ◽  
Gram Negative ◽  
E Coli

Curli are necessary for the adherence of Escherichia coli to surfaces, and to each other, during biofilm formation, and the csgBA and csgDEFG operons are both required for their synthesis. A recent survey of gene expression in Pseudomonas aeruginosa biofilms has identified tolA as a gene activated in biofilms. The tol genes play a fundamental role in maintaining the outer-membrane integrity of Gram-negative bacteria. RcsC, the sensor of the RcsBCD phosphorelay, is involved, together with RcsA, in colanic acid capsule synthesis, and also modulates the expression of tolQRA and csgDEFG. In addition, the RcsBCD phosphorelay is activated in tol mutants or when Tol proteins are overexpressed. These results led the authors to investigate the role of the tol genes in biofilm formation in laboratory and clinical isolates of E. coli. It was shown that the adherence of cells was lowered in the tol mutants. This could be the result of a drastic decrease in the expression of the csgBA operon, even though the expression of csgDEFG was slightly increased under such conditions. It was also shown that the Rcs system negatively controls the expression of the two csg operons in an RcsA-dependent manner. In the tol mutants, activation of csgDEFG occurred via OmpR and was dominant upon repression by RcsB and RcsA, while these two regulatory proteins repressed csgBA through a dominant effect on the activator protein CsgD, thus affecting curli synthesis. The results demonstrate that the Rcs system, previously known to control the synthesis of the capsule and the flagella, is an additional component involved in the regulation of curli. Furthermore, it is shown that the defect in cell motility observed in the tol mutants depends on RcsB and RcsA.

scholarly journals IscR Controls Iron-Dependent Biofilm Formation in Escherichia coli by Regulating Type I Fimbria Expression

2008 ◽  
Vol 191 (4) ◽  
pp. 1248-1257 ◽  
Author(s):  
Yun Wu ◽  
F. Wayne Outten
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Developmental Process ◽  
Bacterial Species ◽  
Type I ◽  
Surface Attachment ◽  
Environmental Signals ◽  
Regulatory Pathways ◽  
E Coli ◽  
Type I Fimbriae

ABSTRACT Biofilm formation is a complex developmental process regulated by multiple environmental signals. In addition to other nutrients, the transition metal iron can also regulate biofilm formation. Iron-dependent regulation of biofilm formation varies by bacterial species, and the exact regulatory pathways that control iron-dependent biofilm formation are often unknown or only partially characterized. To address this gap in our knowledge, we examined the role of iron availability in regulating biofilm formation in Escherichia coli. The results indicate that biofilm formation is repressed under low-iron conditions in E. coli. Furthermore, a key iron regulator, IscR, controls biofilm formation in response to changes in cellular Fe-S homeostasis. IscR regulates the FimE recombinase to control expression of type I fimbriae in E. coli. We propose that iron-dependent regulation of FimE via IscR leads to decreased surface attachment and biofilm dispersal under iron-limiting conditions.

scholarly journals Effects of 462 nm Light-Emitting Diode on the Inactivation of Escherichia coli and a Multidrug-Resistant by Tetracycline Photoreaction

2018 ◽  
Vol 7 (9) ◽  
pp. 278 ◽  
Author(s):  
Shiuh-Tsuen Huang ◽  
Chun-Yi Wu ◽  
Nan‐Yao Lee ◽  
Chien-Wei Cheng ◽  
Meei-Ju Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Blue Light ◽  
High Efficiency ◽  
Light Emitting Diode ◽  
Phosphate Buffer Solution ◽  
Multidrug Resistant ◽  
Molecular Formula ◽  
Light Illumination ◽  
Light Emitting ◽  
E Coli

The adaptability of bacterial resistance to antibiotics contributes to its high efficiency during evolution. Tetracycline (TC) is a broad-spectrum antimicrobial agent. Chromatographic analyses and mass spectrometry were used to study the effects of the light illumination of a 462 nm light-emitting diode (LED) on the conformational changes of TC in a phosphate buffer solution (PBS, pH 7.8). Especially, the inactivation of superoxide anion radicals (O2•−) and Escherichia coli (E. coli), including that of a multidrug-resistant E. coli (MDR E. coli), were investigated during the photolysis of TC. A photolysis product of TC (PPT) was generated in an alkaline solution after the illumination of a blue light. The mass spectra of PPT had characteristic ion signals in m/z 459, 445, and 249.1 Da. The PPT has the molecular formula of C22H22N2O9, and the exact mass is 458.44 g/mol. The inactivation of MDR E. coli is not significant with TC treatment. The drug-resistant ability of MDR E. coli has a less significant effect on PPT, and the changed conformation of TC retained the inactivation ability of MDR E. coli upon blue light photoreaction. With TC, illuminated by a blue light in a pH 7.8 PBS, O2•− was generated from TC photolysis, which enhanced the inactivation of E. coli and MDR E. coli. A 96.6% inactivation rate of MDR E. coli was reached with TC under 2.0 mW/cm2 blue light illumination at 25 ± 3 °C for 120 min, and the effects of the TC-treated photoreaction on MDR E. coli viability repressed the growth of MDR E. coli by 4 to 5 logs. The present study of the blue light photoreaction of TC offers a new approach to the inactivation of MDR E. coli.

scholarly journals The Effect of Blue Light on the Production of Citrinin in Monascus purpureus M9 by Regulating the mraox Gene through lncRNA AOANCR

Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 536 ◽  
Author(s):  
Yang ◽  
Wang ◽  
Li ◽  
Guo ◽  
Yang ◽  
...  
Keyword(s):  
Citric Acid ◽  
Blue Light ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Culture Conditions ◽  
Light Signal ◽  
Monascus Purpureus ◽  
Light Illumination ◽  
Non Coding Rna ◽  
Long Non Coding Rna

Blue light, as an important environmental factor, can regulate the production of various secondary metabolites of Monascus purpureus M9, including mycotoxin-citrinin, pigments, and monacolin K. The analysis of citrinin in Monascus M9 exposed to blue light for 0 min./d, 15 min./d, and 60 min./d showed that 15 min./d of blue light illumination could significantly increase citrinin production, while 60 min./d of blue light illumination decreased citrinin production. Analysis of long non-coding RNA (LncRNA) was performed on the transcripts of Monascus M9 under three culture conditions, and this analysis identified an lncRNA named AOANCR that can negatively regulate the mraox gene. Fermentation studies suggested that alternate respiratory pathways could be among the pathways that are involved in the regulation of the synthesis of citrinin by environmental factors. Aminophylline and citric acid were added to the culture medium to simulate the process of generating cyclic adenosine monophosphate (cAMP) in cells under illumination conditions. The results of the fermentation showed that aminophylline and citric acid could increase the expression of the mraox gene, decrease the expression of lncRNA AOANCR, and reduce the yield of citrinin. This result also indicates a reverse regulation relationship between lncRNA AOANCR and the mraox gene. A blue light signal might regulate the mraox gene at least partially through lncRNA AOANCR, thereby regulating citrinin production. Citrinin has severe nephrotoxicity in mammals, and it is important to control the residual amout of citrinin in red yeast products during fermentation. LncRNA AOANCR and mraox can potentially be used as new targets for the control of citrinin production.

scholarly journals Novel Strategy for Biofilm Inhibition by Using Small Molecules Targeting Molecular Chaperone DnaK

2014 ◽  
Vol 59 (1) ◽  
pp. 633-641 ◽  
Author(s):  
Ken-ichi Arita-Morioka ◽  
Kunitoshi Yamanaka ◽  
Yoshimitsu Mizunoe ◽  
Teru Ogura ◽  
Shinya Sugimoto
Keyword(s):  
Molecular Chaperone ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Dependent Manner ◽  
Cellular Functions ◽  
Biofilm Inhibition ◽  
Content Type ◽  
E Coli ◽  
Chaperone Dnak ◽  
Biofilm Development

ABSTRACTBiofilms are complex communities of microorganisms that attach to surfaces and are embedded in a self-produced extracellular matrix. Since these cells acquire increased tolerance against antimicrobial agents and host immune systems, biofilm-associated infectious diseases tend to become chronic. We show here that the molecular chaperone DnaK is important for biofilm formation and that chemical inhibition of DnaK cellular functions is effective in preventing biofilm development. Genetic, microbial, and microscopic analyses revealed that deletion of thednaKgene markedly reduced the production of the extracellular functional amyloid curli, which contributes to the robustness ofEscherichia colibiofilms. We tested the ability of DnaK inhibitors myricetin (Myr), telmisartan, pancuronium bromide, and zafirlukast to prevent biofilm formation ofE. coli. Only Myr, a flavonol widely distributed in plants, inhibited biofilm formation in a concentration-dependent manner (50% inhibitory concentration [IC50] = 46.2 μM); however, it did not affect growth. Transmission electron microscopy demonstrated that Myr inhibited the production of curli. Phenotypic analyses of thermosensitivity, cell division, intracellular level of RNA polymerase sigma factor RpoH, and vulnerability to vancomycin revealed that Myr altered the phenotype ofE. coliwild-type cells to make them resemble those of the isogenicdnaKdeletion mutant, indicating that Myr inhibits cellular functions of DnaK. These findings provide insights into the significance of DnaK in curli-dependent biofilm formation and indicate that DnaK is an ideal target for antibiofilm drugs.

Indole can act as an extracellular signal to regulate biofilm formation of Escherichia coli and other indole-producing bacteria

2003 ◽  
Vol 49 (7) ◽  
pp. 443-449 ◽  
Author(s):  
P Di Martino ◽  
R Fursy ◽  
L Bret ◽  
B Sundararaju ◽  
R S Phillips
Keyword(s):  
Escherichia Coli ◽  
Mutant Strain ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Klebsiella Oxytoca ◽  
Laboratory Strain ◽  
Luria Bertani ◽  
Dependent Manner ◽  
E Coli ◽  
Signalling Molecule

We demonstrated previously that genetic inactivation of tryptophanase is responsible for a dramatic decrease in biofilm formation in the laboratory strain Escherichia coli S17-1. In the present study, we tested whether the biochemical inhibition of tryptophanase, with the competitive inhibitor oxindolyl-L-alanine, could affect polystyrene colonization by E. coli and other indole-producing bacteria. Oxindolyl-L-alanine inhibits, in a dose-dependent manner, indole production and biofilm formation by strain S17-1 grown in Luria–Bertani (LB) medium. Supplementation with indole at physiologically relevant concentrations restores biofilm formation by strain S17-1 in the presence of oxindolyl-L-alanine and by mutant strain E. coli 3714 (S17-1 tnaA::Tn5) in LB medium. Oxindolyl-L-alanine also inhibits the adherence of S17-1 cells to polystyrene for a 3-h incubation time, but mutant strain 3714 cells are unaffected. At 0.5 mg/mL, oxindolyl-L-alanine exhibits inhibitory activity against biofilm formation in LB medium and in synthetic urine for several clinical isolates of E. coli, Klebsiella oxytoca, Citrobacter koseri, Providencia stuartii, and Morganella morganii but has no affect on indole-negative Klebsiella pneumoniae strains. In conclusion, these data suggest that indole, produced by the action of tryptophanase, is involved in polystyrene colonization by several indole-producing bacterial species. Indole may act as a signalling molecule to regulate the expression of adhesion and biofilm-promoting factors.Key words: Escherichia coli, biofilm, indole, tryptophanase, signalling molecule.

scholarly journals Anti-Biofilm Effect of Octenidine and Polyhexanide on Uropathogenic Biofilm-Producing Bacteria

2021 ◽  
pp. 1-7
Author(s):  
Maria Loose ◽  
Kurt G. Naber ◽  
Larry Purcell ◽  
Manfred P. Wirth ◽  
Florian M.E. Wagenlehner
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
E Coli ◽  
Mueller Hinton ◽  
High Dilutions ◽  
Artificial Urine ◽  
Tract Infections ◽  
Mueller Hinton Broth

<b><i>Background:</i></b> A catheter allowing a release of antibacterial substances such as antiseptics into the bladder could be a new way of preventing biofilm formation and subsequent catheter-associated urinary tract infections. <b><i>Methods:</i></b> Minimal inhibitory and bactericidal concentration (MIC/MBC) determinations in cation-adjusted Mueller-Hinton broth and artificial urine were performed for 4 antiseptics against 3 uropathogenic biofilm producers, <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>, and <i>Proteus mirabilis</i>. Furthermore, effects of octenidine and polyhexanide against catheter biofilm formation were determined by quantification of biofilm-producing bacteria. <b><i>Results:</i></b> Sodium hypochlorite showed MIC/MBC values between 200 and 800 mg/L for all strains tested. Triclosan was efficient against <i>E. coli</i> and <i>P. mirabilis</i> (MIC ≤2.98 mg/L) but ineffective against <i>P. aeruginosa</i>. Octenidine and polyhexanide showed antibacterial activity against all 3 species tested (MIC 1.95–7.8 and 3.9–31.25 mg/L). Both octenidine and polyhexanide were able to prevent biofilm formation on catheter segments in a concentration dependent manner. Furthermore, adding 250 mg/L of each biocide disrupted biofilms formed by <i>E. coli</i> and <i>P. mirabilis</i>, whereas even 500 mg/L was not sufficient to completely destroy <i>P. aeruginosa</i> biofilms. <b><i>Conclusion:</i></b> Octenidine- and polyhexanide-containing antiseptics showed a broad effect against typical uropathogenic biofilm producers even in high dilutions. This study provides a basis for further investigation of the potential of octenidine and polyhexanide as prophylaxis or treatment of catheter biofilms.

scholarly journals TosR-Mediated Regulation of Adhesins and Biofilm Formation in UropathogenicEscherichia coli

mSphere ◽  
2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Courtney L. Luterbach ◽  
Valerie S. Forsyth ◽  
Michael D. Engstrom ◽  
Harry L. T. Mobley
Keyword(s):  
Urinary Tract ◽  
Cross Talk ◽  
Biofilm Formation ◽  
Dependent Manner ◽  
Rna Seq ◽  
Concentration Dependent Manner ◽  
Content Type ◽  
E Coli ◽  
Expression Of Genes ◽  
Invasive Infections

ABSTRACTUropathogenicEscherichia colistrains utilize a variety of adherence factors that assist in colonization of the host urinary tract. TosA (typeonesecretionA) is a nonfimbrial adhesin that is predominately expressed during murine urinary tract infection (UTI), binds to kidney epithelial cells, and promotes survival during invasive infections. ThetosRCBDAEFoperon encodes the secretory machinery necessary for TosA localization to theE. colicell surface, as well as the transcriptional regulator TosR. TosR binds upstream of thetosoperon and in a concentration-dependent manner either induces or repressestosAexpression. TosR is a member of the PapB family of fimbrial regulators that can participate in cross talk between fimbrial operons. TosR also binds upstream of thepapoperon and suppresses PapA production. However, the scope of TosR-mediated cross talk is understudied and may be underestimated. To quantify the global effects of TosR-mediated regulation on theE. coliCFT073 genome, we induced expression oftosR, collected mRNA, and performed high-throughput RNA sequencing (RNA-Seq). These findings show that production of TosR affected the expression of genes involved with adhesins, including P, F1C, and Auf fimbriae, nitrate-nitrite transport, microcin secretion, and biofilm formation.IMPORTANCEUropathogenicE. colistrains cause the majority of UTIs, which are the second most common bacterial infection in humans. During a UTI, bacteria adhere to cells within the urinary tract, using a number of different fimbrial and nonfimbrial adhesins. Biofilms can also develop on the surfaces of catheters, resulting in complications such as blockage. In this work, we further characterized the regulator TosR, which links both adhesin production and biofilm formation and likely plays a crucial function during UTI and disseminated infection.

scholarly journals Dimethyl Sulfoxide and Ethanol Elicit Increased Amyloid Biogenesis and Amyloid-Integrated Biofilm Formation in Escherichia coli

2012 ◽  
Vol 78 (9) ◽  
pp. 3369-3378 ◽  
Author(s):  
Ji Youn Lim ◽  
Janine M. May ◽  
Lynette Cegelski
Keyword(s):  
Escherichia Coli ◽  
Dimethyl Sulfoxide ◽  
Biofilm Formation ◽  
Amyloid Fibers ◽  
Content Type ◽  
Bacterial Physiology ◽  
E Coli ◽  
Fiber Assembly ◽  
Community Function ◽  
Molecular Alterations

ABSTRACTEscherichia colidirects the assembly of functional amyloid fibers termed “curli” that mediate adhesion and biofilm formation. We discovered thatE. coliexhibits a tunable and selective increase in curli protein expression and fiber assembly in response to moderate concentrations of dimethyl sulfoxide (DMSO) and ethanol. Furthermore, the molecular alterations resulted in dramatic functional phenotypes associated with community behavior, including (i) cellular agglutination in broth, (ii) altered colony morphology, and (iii) increased biofilm formation. Solid-state nuclear magnetic resonance (NMR) spectra of intact pellicles formed in the presence of [13C2]DMSO confirmed that DMSO was not being transformed and utilized directly for metabolism. Collectively, the chemically induced phenotypes emphasize the plasticity ofE. coli's response to environmental stimuli to enhance amyloid production and amyloid-integrated biofilm formation. The data also support our developing model of the extracellular matrix as an organized assembly of polymeric components, including amyloid fibers, in which composition relates to bacterial physiology and community function.

Control of Escherichia coli O157:H7 Motility and Biofilm Formation by Salicylate and Decanoate: MarA/SoxS/Rob and pchE Interactions

2021 ◽  
Author(s):  
Gaylen A. Uhlich ◽  
Heather S. Koppenhöfer ◽  
Nereus W. Gunther ◽  
Amy R. Ream
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Biofilm Formation ◽  
Environmental Persistence ◽  
Regulatory Pathways ◽  
Promoter Sequences ◽  
E Coli ◽  
Sodium Decanoate ◽  
Incubation Temperatures ◽  
Biofilm Inhibitor

Prophage-encoded Escherichia coli O157:H7 transcription factor (TF), PchE, inhibits biofilm formation and attachment to cultured epithelial cells by reducing curli fimbriae expression and increasing flagella expression. To identify pchE regulators that might be used in intervention strategies to reduce environmental persistence or host infections, we performed a computational search of O157:H7 strain PA20 pchE promoter sequences for binding sites used by known TFs. A common site shared by MarA/SoxS/Rob TFs was identified and the typical MarA/Rob inducers, salicylate and decanoate, were tested for biofilm and motility effects. Sodium salicylate, a proven biofilm inhibitor, but not sodium decanoate, strongly reduced O157:H7 biofilms by a pchE -independent mechanism. Both salicylate and decanoate enhanced O157:H7 motility dependent on pchE using media and incubation temperatures optimum for culturing human epithelial cells. However, induction of pchE by salicylate did not activate the SOS response. MarA/SoxS/Rob inducers provide new potential agents for controlling O157:H7 interactions with the host and its persistence in the environment. IMPORTANCE There is a need to develop E. coli serotype O157:H7 non-antibiotic interventions that do not precipitate the release and activation of virulence factor-encoded prophage and transferrable genetic elements. One method is to stimulate existing regulatory pathways that repress bacterial persistence and virulence genes. Here we show that certain inducers of MarA and Rob have that ability, working through both pchE -dependent and -independent pathways.

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