scholarly journals Rcs Phosphorelay Activation in Cardiolipin-DeficientEscherichia coliReduces Biofilm Formation

2019 ◽  
Vol 201 (9) ◽  
Author(s):  
Julia F. Nepper ◽  
Yin C. Lin ◽  
Douglas B. Weibel
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Lipid Membrane ◽  
Protein Translocation ◽  
Membrane Composition ◽  
Anionic Phospholipid ◽  
Content Type ◽  
Envelope Stress ◽  
Biofilm Development

ABSTRACTBiofilm formation is a complex process that requires a number of transcriptional, proteomic, and physiological changes to enable bacterial survival. The lipid membrane presents a barrier to communication between the machinery within bacteria and the physical and chemical features of their extracellular environment, and yet little is known about how the membrane influences biofilm development. We found that depleting the anionic phospholipid cardiolipin reduces biofilm formation inEscherichia colicells by as much as 50%. The absence of cardiolipin activates the regulation of colanic acid synthesis (Rcs) envelope stress response, which represses the production of flagella, disrupts initial biofilm attachment, and reduces biofilm growth. We demonstrate that a reduction in the concentration of cardiolipin impairs translocation of proteins across the inner membrane, which we hypothesize activates the Rcs pathway through the outer membrane lipoprotein RcsF. Our study demonstrates a molecular connection between the composition of membrane phospholipids and biofilm formation inE. coliand suggests that altering lipid biosynthesis may be a viable approach for altering biofilm formation and possibly other multicellular phenotypes related to bacterial adaptation and survival.IMPORTANCEThere is a growing interest in the role of lipid membrane composition in the physiology and adaptation of bacteria. We demonstrate that a reduction in the anionic phospholipid cardiolipin impairs biofilm formation inEscherichia colicells. Depleting cardiolipin reduced protein translocation across the inner membrane and activated the Rcs envelope stress response. Consequently, cardiolipin depletion produced cells lacking assembled flagella, which impacted their ability to attach to surfaces and seed the earliest stage in biofilm formation. This study provides empirical evidence for the role of anionic phospholipid homeostasis in protein translocation and its effect on biofilm development and highlights modulation of the membrane composition as a potential method of altering bacterial phenotypes related to adaptation and survival.

scholarly journals Rcs phosphorelay activation in cardiolipin-deficient Escherichia coli reduces biofilm formation

2019 ◽  
Author(s):  
Julia F. Nepper ◽  
Yin C. Lin ◽  
Douglas B. Weibel
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Biofilm Formation ◽  
Lipid Membrane ◽  
Protein Translocation ◽  
Membrane Composition ◽  
Anionic Phospholipid ◽  
Envelope Stress ◽  
Biofilm Development

AbstractBiofilm formation is a complex process that requires a number of transcriptional, proteomic, and physiological changes to enable bacterial survival. The lipid membrane presents a barrier to communication between the machinery within bacteria and the physical and chemical features of their extracellular environment, and yet little is known about how the membrane influences biofilm development. We found that depleting the anionic phospholipid cardiolipin reduces biofilm formation in Escherichia coli cells by as much as 50%. The absence of cardiolipin activates the Rcs envelope stress response, which represses production of flagella, disrupts initial biofilm attachment, and reduces biofilm growth. We demonstrate that a reduction in the concentration of cardiolipin impairs translocation of proteins across the inner membrane, which we hypothesize activates the Rcs pathway through the outer membrane lipoprotein RcsF. Our study demonstrates a molecular connection between the composition of membrane phospholipids and biofilm formation in E. coli and suggests that altering lipid biosynthesis may be a viable approach for altering biofilm formation and possibly other multicellular phenotypes related to bacterial adaptation and survival.ImportanceThere is a growing interest in the role of lipid membrane composition in the physiology and adaptation of bacteria. We demonstrate that a reduction in the anionic phospholipid cardiolipin impairs biofilm formation in Escherichia coli cells. Depleting cardiolipin reduced protein translocation across the inner membrane and activated the Rcs envelope stress response. Consequently, cardiolipin depletion produced cells lacking assembled flagella, which impacted their ability to attach to surfaces and seed the earliest stage in biofilm formation. This study provides empirical evidence for the role of anionic phospholipid homeostasis in protein translocation and its effect on biofilm development, and highlights modulation of the membrane composition as a potential method of altering bacterial phenotypes related to adaptation and survival.

scholarly journals Role ofrpoSin Escherichia coli O157:H7 Strain H32 Biofilm Development and Survival

2012 ◽  
Vol 78 (23) ◽  
pp. 8331-8339 ◽  
Author(s):  
Jessica R. Sheldon ◽  
Mi-Sung Yim ◽  
Jessica H. Saliba ◽  
Wai-Hong Chung ◽  
Kwok-Yin Wong ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Lake Water ◽  
Biofilm Formation ◽  
Survival Rates ◽  
Confocal Scanning Laser Microscopy ◽  
Wild Type ◽  
Minimal Growth ◽  
Content Type ◽  
Biofilm Development

ABSTRACTThe protein RpoS is responsible for mediating cell survival during the stationary phase by conferring cell resistance to various stressors and has been linked to biofilm formation. In this study, the role of therpoSgene inEscherichia coliO157:H7 biofilm formation and survival in water was investigated. Confocal scanning laser microscopy of biofilms established on coverslips revealed a nutrient-dependent role ofrpoSin biofilm formation, where the biofilm biomass volume of therpoSmutant was 2.4- to 7.5-fold the size of itsrpoS+wild-type counterpart in minimal growth medium. The enhanced biofilm formation of therpoSmutant did not, however, translate to increased survival in sterile double-distilled water (ddH2O), filter-sterilized lake water, or unfiltered lake water. TherpoSmutant had an overall reduction of 3.10 and 5.30 log10in sterile ddH2O and filter-sterilized lake water, respectively, while only minor reductions of 0.53 and 0.61 log10in viable counts were observed for the wild-type form in the two media over a 13-day period, respectively. However, the survival rates of the detached biofilm-derivedrpoS+andrpoSmutant cells were comparable. Under the competitive stress conditions of unfiltered lake water, the advantage conferred by the presence ofrpoSwas lost, and both the wild-type and knockout forms displayed similar declines in viable counts. These results suggest thatrpoSdoes have an influence on both biofilm formation and survival ofE. coliO157:H7 and that the advantage conferred byrpoSis contingent on the environmental conditions.

scholarly journals Dissection of the Role of Pili and Type 2 and 3 Secretion Systems in Adherence and Biofilm Formation of an Atypical Enteropathogenic Escherichia coli Strain

2013 ◽  
Vol 81 (10) ◽  
pp. 3793-3802 ◽  
Author(s):  
Rodrigo T. Hernandes ◽  
Miguel A. De la Cruz ◽  
Denise Yamamoto ◽  
Jorge A. Girón ◽  
Tânia A. T. Gomes
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Coli Strain ◽  
Mass Spectrometry Analysis ◽  
Secretion Systems ◽  
Content Type ◽  
Spectrometry Analysis ◽  
Rigid Rod

ABSTRACTAtypical enteropathogenicEscherichia coli(aEPEC) strains are diarrheal pathogens that lack bundle-forming pilus production but possess the virulence-associated locus of enterocyte effacement. aEPEC strain 1551-2 produces localized adherence (LA) on HeLa cells; however, its isogenic intimin (eae) mutant produces a diffuse-adherence (DA) pattern. In this study, we aimed to identify the DA-associated adhesin of the 1551-2eaemutant. Electron microscopy of 1551-2 identified rigid rod-like pili composed of an 18-kDa protein, which was identified as the major pilin subunit of type 1 pilus (T1P) by mass spectrometry analysis. Deletion offimAin 1551-2 affected biofilm formation but had no effect on adherence properties. Analysis of secreted proteins in supernatants of this strain identified a 150-kDa protein corresponding to SslE, a type 2 secreted protein that was recently reported to be involved in biofilm formation of rabbit and human EPEC strains. However, neither adherence nor biofilm formation was affected in a 1551-2sslEmutant. We then investigated the role of the EspA filament associated with the type 3 secretion system (T3SS) in DA by generating a doubleeae espAmutant. This strain was no longer adherent, strongly suggesting that the T3SS translocon is the DA adhesin. In agreement with these results, specific anti-EspA antibodies blocked adherence of the 1551-2eaemutant. Our data support a role for intimin in LA, for the T3SS translocon in DA, and for T1P in biofilm formation, all of which may act in concert to facilitate host intestinal colonization by aEPEC strains.

scholarly journals Acquisition and Role of Molybdate in Pseudomonas aeruginosa

2014 ◽  
Vol 80 (21) ◽  
pp. 6843-6852 ◽  
Author(s):  
Victoria G. Pederick ◽  
Bart A. Eijkelkamp ◽  
Miranda P. Ween ◽  
Stephanie L. Begg ◽  
James C. Paton ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fatty Acid Composition ◽  
Nitrate Reduction ◽  
Biofilm Formation ◽  
Energy Production ◽  
Anaerobic Growth ◽  
Membrane Composition ◽  
Content Type ◽  
High Affinity

ABSTRACTIn microaerophilic or anaerobic environments,Pseudomonas aeruginosautilizes nitrate reduction for energy production, a process dependent on the availability of the oxyanionic form of molybdenum, molybdate (MoO42−). Here, we show that molybdate acquisition inP. aeruginosaoccurs via a high-affinity ATP-binding cassette permease (ModABC). ModA is a cluster D-III solute binding protein capable of interacting with molybdate or tungstate oxyanions. Deletion of themodAgene reduces cellular molybdate concentrations and results in inhibition of anaerobic growth and nitrate reduction. Further, we show that conditions that permit nitrate reduction also cause inhibition of biofilm formation and an alteration in fatty acid composition ofP. aeruginosa. Collectively, these data highlight the importance of molybdate for anaerobic growth ofP. aeruginosaand reveal novel consequences of nitrate reduction on biofilm formation and cell membrane composition.

scholarly journals Novel Role for the Streptococcus pneumoniae Toxin Pneumolysin in the Assembly of Biofilms

mBio ◽  
2013 ◽  
Vol 4 (5) ◽  
Author(s):  
Joshua R. Shak ◽  
Herbert P. Ludewick ◽  
Kristen E. Howery ◽  
Fuminori Sakai ◽  
Hong Yi ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Hemolytic Activity ◽  
Biofilm Formation ◽  
Early Time ◽  
Wild Type ◽  
Knockout Mutant ◽  
Content Type ◽  
Biofilm Development ◽  
Almost All

ABSTRACTStreptococcus pneumoniaeis an important commensal and pathogen responsible for almost a million deaths annually in children under five. The formation of biofilms byS. pneumoniaeis important in nasopharyngeal colonization, pneumonia, and otitis media. Pneumolysin (Ply) is a toxin that contributes significantly to the virulence ofS. pneumoniaeand is an important candidate as a serotype-independent vaccine target. Having previously demonstrated that aluxSknockout mutant was unable to form early biofilms and expressed lessplymRNA than the wild type, we conducted a study to investigate the role of Ply in biofilm formation. We found that Ply was expressed in early phases of biofilm development and localized to cellular aggregates as early as 4 h postinoculation.S. pneumoniae plyknockout mutants in D39 and TIGR4 backgrounds produced significantly less biofilm biomass than wild-type strains at early time points, both on polystyrene and on human respiratory epithelial cells, cultured under static or continuous-flow conditions. Ply’s role in biofilm formation appears to be independent of its hemolytic activity, asS. pneumoniaeserotype 1 strains, which produce a nonhemolytic variant of Ply, were still able to form biofilms. Transmission electron microscopy of biofilms grown on A549 lung cells using immunogold demonstrated that Ply was located both on the surfaces of pneumococcal cells and in the extracellular biofilm matrix. Altogether, our studies demonstrate a novel role for pneumolysin in the assembly ofS. pneumoniaebiofilms that is likely important during both carriage and disease and therefore significant for pneumolysin-targeting vaccines under development.IMPORTANCEThe bacteriumStreptococcus pneumoniae(commonly known as the pneumococcus) is commonly carried in the human nasopharynx and can spread to other body sites to cause disease. In the nasopharynx, middle ear, and lungs, the pneumococcus forms multicellular surface-associated structures called biofilms. Pneumolysin is an important toxin produced by almost allS. pneumoniaestrains, extensively studied for its ability to cause damage to human tissue. In this paper, we demonstrate that pneumolysin has a previously unrecognized role in biofilm formation by showing that strains without pneumolysin are unable to form the same amount of biofilm on plastic and human cell substrates. Furthermore, we show that the role of pneumolysin in biofilm formation is separate from the hemolytic activity responsible for tissue damage during pneumococcal diseases. This novel role for pneumolysin suggests that pneumococcal vaccines directed against this protein should be investigated for their potential impact on biofilms formed during carriage and disease.

scholarly journals σBInhibits Poly-N-Acetylglucosamine Exopolysaccharide Synthesis and Biofilm Formation inStaphylococcus aureus

2019 ◽  
Vol 201 (11) ◽  
Author(s):  
Jaione Valle ◽  
Maite Echeverz ◽  
Iñigo Lasa
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Flow Conditions ◽  
Content Type ◽  
Environmental Signals ◽  
General Stress Response ◽  
Biofilm Development ◽  
Type Strains ◽  
Complex Regulatory Network

ABSTRACTStaphylococcus aureusclinical strains are able to produce at least two distinct types of biofilm matrixes: biofilm matrixes made of the polysaccharide intercellular adhesin (PIA) or poly-N-acetylglucosamine (PNAG), whose synthesis is mediated by theicaADBClocus, and biofilm matrixes built of proteins (polysaccharide independent). σBis a conserved alternative sigma factor that regulates the expression of more than 100 genes in response to changes in environmental conditions. While numerous studies agree that σBis required for polysaccharide-independent biofilms, controversy persists over the role of σBin the regulation of PIA/PNAG-dependent biofilm development. Here, we show that genetically unrelatedS. aureusσB-deficient strains produced stronger biofilms under both static and flow conditions and accumulated higher levels of PIA/PNAG exopolysaccharide than their corresponding wild-type strains. The increased accumulation of PIA/PNAG in the σBmutants correlated with a greater accumulation of the IcaC protein showed that it was not due to adjustments inicaADBCoperon transcription and/oricaADBCmRNA stability. Overall, our results reveal that in the presence of active σB, the turnover of Ica proteins is accelerated, reducing the synthesis of PIA/PNAG exopolysaccharide and consequently the PIA/PNAG-dependent biofilm formation capacity.IMPORTANCEDue to its multifaceted lifestyle,Staphylococcus aureusneeds a complex regulatory network to connect environmental signals with cellular physiology. One particular transcription factor, named σB(SigB), is involved in the general stress response and the expression of virulence factors. For many years, great confusion has existed about the role of σBin the regulation of the biofilm lifestyle inS. aureus. Our study demonstrated that σBis not necessary for exopolysaccharide-dependent biofilms and, even more, thatS. aureusproduces stronger biofilms in the absence of σB. The increased accumulation of exopolysaccharide correlates with higher stability of the proteins responsible for its synthesis. The present findings reveal an additional regulatory layer to control biofilm exopolysaccharide synthesis under stress conditions.

scholarly journals BolA Is a Transcriptional Switch That Turns Off Motility and Turns On Biofilm Development

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Clémentine Dressaire ◽  
Ricardo Neves Moreira ◽  
Susana Barahona ◽  
António Pedro Alves de Matos ◽  
Cecília Maria Arraiano
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Extracellular Polysaccharides ◽  
Bacterial Cells ◽  
Content Type ◽  
Bacterial Transcription ◽  
A Genome ◽  
Exact Function ◽  
Transcriptional Switch ◽  
Biofilm Development

ABSTRACTBacteria are extremely versatile organisms that rapidly adapt to changing environments. When bacterial cells switch from planktonic growth to biofilm, flagellum formation is turned off and the production of fimbriae and extracellular polysaccharides is switched on. BolA is present in most Gram-negative bacteria, and homologues can be found from proteobacteria to eukaryotes. Here, we show that BolA is a new bacterial transcription factor that modulates the switch from a planktonic to a sessile lifestyle. It negatively modulates flagellar biosynthesis and swimming capacity inEscherichia coli. Furthermore, BolA overexpression favors biofilm formation, involving the production of fimbria-like adhesins and curli. Our results also demonstrate that BolA is a protein with high affinity to DNA and is able to regulate many genes on a genome-wide scale. Moreover, we show that the most significant targets of this protein involve a complex network of genes encoding proteins related to biofilm development. Herein, we propose that BolA is a motile/adhesive transcriptional switch, specifically involved in the transition between the planktonic and the attachment stage of biofilm formation.IMPORTANCEEscherichia colicells possess several mechanisms to cope with stresses. BolA has been described as a protein important for survival in late stages of bacterial growth and under harsh environmental conditions. BolA-like proteins are widely conserved from prokaryotes to eukaryotes. Although their exact function is not fully established at the molecular level, they seem to be involved in cell proliferation or cell cycle regulation. Here, we unraveled the role of BolA in biofilm development and bacterial motility. Our work suggests that BolA actively contributes to the decision of bacteria to arrest flagellar production and initiate the attachment to form structured communities, such as biofilms. The molecular studies of different lifestyles coupled with the comprehension of the BolA functions may be an important step for future perspectives, with health care and biotechnology applications.

scholarly journals Role of quorum sensing in UVA-induced biofilm formation in Pseudomonas aeruginosa

Microbiology ◽  
2020 ◽  
Vol 166 (8) ◽  
pp. 735-750 ◽  
Author(s):  
Magdalena Pezzoni ◽  
Ramón A. Pizarro ◽  
Cristina S. Costa
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Type Species ◽  
Transcriptional Level ◽  
Content Type ◽  
Link Type ◽  
Opportunistic Human Pathogen ◽  
Biofilm Development

Pseudomonas aeruginosa , a versatile bacterium present in terrestrial and aquatic environments and a relevant opportunistic human pathogen, is largely known for the production of robust biofilms. The unique properties of these structures complicate biofilm eradication, because they make the biofilms very resistant to diverse antibacterial agents. Biofilm development and establishment is a complex process regulated by multiple regulatory genetic systems, among them is quorum sensing (QS), a mechanism employed by bacteria to regulate gene transcription in response to population density. In addition, environmental factors such as UVA radiation (400–315 nm) have been linked to biofilm formation. In this work, we further investigate the mechanism underlying the induction of biofilm formation by UVA, analysing the role of QS in this phenomenon. We demonstrate that UVA induces key genes of the Las and Rhl QS systems at the transcriptional level. We also report that pelA and pslA genes, which are essential for biofilm formation and whose transcription depends in part on QS, are significantly induced under UVA exposure. Finally, the results demonstrate that in a relA strain (impaired for ppGpp production), the UVA treatment does not induce biofilm formation or QS genes, suggesting that the increase of biofilm formation due to exposure to UVA in P. aeruginosa could rely on a ppGpp-dependent QS induction.

scholarly journals Role of PBPD1 in Stimulation of Listeria monocytogenes Biofilm Formation by Subminimal Inhibitory β-Lactam Concentrations

2014 ◽  
Vol 58 (11) ◽  
pp. 6508-6517 ◽  
Author(s):  
Uyen T. Nguyen ◽  
Hanjeong Harvey ◽  
Andrew J. Hogan ◽  
Alexandria C. F. Afonso ◽  
Gerard D. Wright ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Biofilm Formation ◽  
Regulatory System ◽  
Content Type ◽  
Food Borne ◽  
Approved Drugs ◽  
Biofilm Development ◽  
Fda Approved Drugs ◽  
Stimulation Of

ABSTRACTDisinfectant-tolerantListeria monocytogenesbiofilms can colonize surfaces that come into contact with food, leading to contamination and, potentially, food-borne illnesses. To better understand the process ofL. monocytogenesbiofilm formation and dispersal, we screened 1,120 off-patent FDA-approved drugs and identified several that modulateListeriabiofilm development. Among the hits were more than 30 β-lactam antibiotics, with effects ranging from inhibiting (≤50%) to stimulating (≥200%) biofilm formation compared to control. Most β-lactams also dispersed a substantial proportion of established biofilms. This phenotype did not necessarily involve killing, as >50% dispersal could be achieved with concentrations as low as 1/20 of the MIC of some cephalosporins. Penicillin-binding protein (PBP) profiling using a fluorescent penicillin analogue showed similar inhibition patterns for most β-lactams, except that biofilm-stimulatory drugs did not bind PBPD1, a low-molecular-weightd,d-carboxypeptidase. Compared to the wild type, apbpD1mutant had an attenuated biofilm response to stimulatory β-lactams. The cephalosporin-responsive CesRK two-component regulatory system, whose regulon includes PBPs, was not required for the response. The requirement for PBPD1 activity for β-lactam stimulation ofL. monocytogenesbiofilms shows that the specific set of PBPs that are inactivated by a particular drug dictates whether a protective biofilm response is provoked.

scholarly journals Evidence for Escherichia coli Diguanylate Cyclase DgcZ Interlinking Surface Sensing and Adhesion via Multiple Regulatory Routes

2016 ◽  
Vol 198 (18) ◽  
pp. 2524-2535 ◽  
Author(s):  
Egidio Lacanna ◽  
Colette Bigosch ◽  
Volkhard Kaever ◽  
Alex Boehm ◽  
Anke Becker
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Primary Role ◽  
Bacterial Cells ◽  
Diguanylate Cyclase ◽  
Surface Attachment ◽  
Content Type ◽  
Surface Sensing

ABSTRACTDgcZ is the main cyclic dimeric GMP (c-di-GMP)-producing diguanylate cyclase (DGC) controlling biosynthesis of the exopolysaccharide poly-β-1,6-N-acetylglucosamine (poly-GlcNAc or PGA), which is essential for surface attachment ofEscherichia coli. Although the complex regulation of DgcZ has previously been investigated, its primary role and the physiological conditions under which the protein is active are not fully understood. Transcription ofdgcZis regulated by the two-component system CpxAR activated by the lipoprotein NlpE in response to surface sensing. Here, we show that the negative effect of acpxRmutation and the positive effect ofnlpEoverexpression on biofilm formation both depend on DgcZ. Coimmunoprecipitation data suggest several potential interaction partners of DgcZ. Interaction with FrdB, a subunit of the fumarate reductase complex (FRD) involved in anaerobic respiration and in control of flagellum assembly, was further supported by a bacterial-two-hybrid assay. Furthermore, the FRD complex was required for the increase in DgcZ-mediated biofilm formation upon induction of oxidative stress by addition of paraquat. A DgcZ-mVENUS fusion protein was found to localize at one bacterial cell pole in response to alkaline pH and carbon starvation. Based on our data and previous knowledge, an integrative role of DgcZ in regulation of surface attachment is proposed. We speculate that both DgcZ-stimulated PGA biosynthesis and interaction of DgcZ with the FRD complex contribute to impeding bacterial escape from the surface.IMPORTANCEBacterial cells can grow by clonal expansion to surface-associated biofilms that are ubiquitous in the environment but also constitute a pervasive problem related to bacterial infections. Cyclic dimeric GMP (c-di-GMP) is a widespread bacterial second messenger involved in regulation of motility and biofilm formation, and plays a primary role in bacterial surface attachment.E. colipossesses a plethora of c-di-GMP-producing diguanylate cyclases, including DgcZ. Our study expands the knowledge on the role of DgcZ in regulation of surface attachment and suggests that it interconnects surface sensing and adhesion via multiple routes.

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