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.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

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 Synthetic Porcine Hepcidin Exhibits Different Roles in Escherichia coli and Salmonella Infections

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Dan Liu ◽  
Zhen-Shun Gan ◽  
Wan Ma ◽  
Hai-Tao Xiong ◽  
Yun-Qing Li ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Iron Status ◽  
Iron Chelator ◽  
Intracellular Iron ◽  
Content Type ◽  
Defense Strategies ◽  
Salmonella Infections

ABSTRACT Hepcidin, an antimicrobial peptide, was discovered to integrate diverse signals from iron status and an infection threat and orchestrate a series of host-protective responses. Several studies have investigated the antimicrobial role of hepcidin, but the results have been controversial. Here, we aimed to examine the role of hepcidin in bacterial adherence and invasion in vitro. We found that porcine hepcidin could decrease the amount of the extracellular pathogen enterotoxigenic Escherichia coli (ETEC) K88 that adhered to cells because it caused the aggregation of the bacteria. However, addition of hepcidin to macrophages infected with the intracellular pathogen Salmonella enterica serovar Typhimurium enhanced the intracellular growth of the pathogen through the degradation of ferroportin, an iron export protein, and then the sequestration of intracellular iron. Intracellular iron was unavailable by use of the iron chelator deferiprone (DFO), which reduced intracellular bacterial growth. These results demonstrate that hepcidin exhibits different functions in extracellular and intracellular bacterial infections, which suggests that different defense strategies should be taken to prevent bacterial infection.

scholarly journals FNR Regulates Expression of Important Virulence Factors Contributing to Pathogenicity of Uropathogenic Escherichia coli

2014 ◽  
Vol 82 (12) ◽  
pp. 5086-5098 ◽  
Author(s):  
Nicolle L. Barbieri ◽  
Bryon Nicholson ◽  
Ashraf Hussein ◽  
Wentong Cai ◽  
Yvonne M. Wannemuehler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Uropathogenic Escherichia Coli ◽  
Type I ◽  
Wild Type ◽  
Global Regulator ◽  
Content Type ◽  
Tract Infections

ABSTRACTUropathogenicEscherichia coli(UPEC) is responsible for the majority of urinary tract infections (UTIs), which are some of the world's most common bacterial infections of humans. Here, we examined the role of FNR (fumarate andnitratereduction), a well-known global regulator, in the pathogenesis of UPEC infections. We constructed anfnrdeletion mutant of UPEC CFT073 and compared it to the wild type for changes in virulence, adherence, invasion, and expression of key virulence factors. Compared to the wild type, thefnrmutant was highly attenuated in the mouse model of human UTI and showed severe defects in adherence to and invasion of bladder and kidney epithelial cells. Our results showed that FNR regulates motility and multiple virulence factors, including expression of type I and P fimbriae, modulation of hemolysin expression, and expression of a novel pathogenicity island involved in α-ketoglutarate metabolism under anaerobic conditions. Our results demonstrate that FNR is a key global regulator of UPEC virulence and controls expression of important virulence factors that contribute to UPEC pathogenicity.

scholarly journals The Effects of β-Lactam Antibiotics on Surface Modifications of Multidrug-Resistant Escherichia coli: A Multiscale Approach

2019 ◽  
Vol 25 (1) ◽  
pp. 135-150 ◽  
Author(s):  
Samuel C. Uzoechi ◽  
Nehal I. Abu-Lail
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Treatment Strategies ◽  
Multidrug Resistant ◽  
Multiscale Approach ◽  
Bacterial Cells ◽  
Adhesion Forces ◽  
E Coli ◽  
Resistant Strains

AbstractPossible multidrug-resistant (MDR) mechanisms of four resistant strains of Escherichia coli to a model β-lactam, ampicillin, were investigated using contact angle measurements of wettability, crystal violet assays of permeability, biofilm formation, fluorescence imaging, and nanoscale analyses of dimensions, adherence, and roughness. Upon exposure to ampicillin, one of the resistant strains, E. coli A5, changed its phenotype from elliptical to spherical, maintained its roughness and biofilm formation abilities, decreased its length and surface area, maintained its cell wall integrity, increased its hydrophobicity, and decreased its nanoscale adhesion to a model surface of silicon nitride. Such modifications are suggested to allow these cells to conserve energy during metabolic dormancy. In comparison, resistant strains E. coli D4, A9, and H5 elongated their cells, increased their roughness, increased their nanoscale adhesion forces, became more hydrophilic, and increased their biofilm formation upon exposure to ampicillin. These results suggest that these strains resisted ampicillin through biofilm formation that possibly introduces diffusion limitations to antibiotics. Investigations of how MDR bacterial cells modify their surfaces in response to antibiotics can guide research efforts aimed at designing more effective antibiotics and new treatment strategies for MDR bacterial infections.

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 Effects of a Mutation in thegyrAGene on the Virulence of Uropathogenic Escherichia coli

2015 ◽  
Vol 59 (8) ◽  
pp. 4662-4668 ◽  
Author(s):  
Javier Sánchez-Céspedes ◽  
Emma Sáez-López ◽  
N. Frimodt-Møller ◽  
Jordi Vila ◽  
Sara M. Soto
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Dna Supercoiling ◽  
Uropathogenic Escherichia Coli ◽  
Topoisomerase Iv ◽  
Content Type ◽  
E Coli ◽  
Type Gene ◽  
Encoding Genes

ABSTRACTFluoroquinolones are among the drugs most extensively used for the treatment of bacterial infections in human and veterinary medicine. Resistance to quinolones can be chromosome or plasmid mediated. The chromosomal mechanism of resistance is associated with mutations in the DNA gyrase- and topoisomerase IV-encoding genes and mutations in regulatory genes affecting different efflux systems, among others. We studied the role of the acquisition of a mutation in thegyrAgene in the virulence and protein expression of uropathogenicEscherichia coli(UPEC). The HC14366M strain carrying a mutation in thegyrAgene (S83L) was found to lose the capacity to cause cystitis and pyelonephritis mainly due to a decrease in the expression of thefimA,papA,papB, andompAgenes. The levels of expression of thefimA,papB, andompAgenes were recovered on complementing the strain with a plasmid containing thegyrAwild-type gene. However, only a slight recovery was observed in the colonization of the bladder in the GyrA complement strain compared to the mutant strain in a murine model of ascending urinary tract infection. In conclusion, a mutation in thegyrAgene of uropathogenicE. colireduced the virulence of the bacteria, likely in association with the effect of DNA supercoiling on the expression of several virulence factors and proteins, thereby decreasing their capacity to cause cystitis and pyelonephritis.

scholarly journals Effect of Micro- and Nanoscale Topography on the Adhesion of Bacterial Cells to Solid Surfaces

2013 ◽  
Vol 79 (8) ◽  
pp. 2703-2712 ◽  
Author(s):  
Lillian C. Hsu ◽  
Jean Fang ◽  
Diana A. Borca-Tasciuc ◽  
Randy W. Worobo ◽  
Carmen I. Moraru
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Bacterial Attachment ◽  
Listeria Innocua ◽  
Solid Surfaces ◽  
Bacterial Cells ◽  
Content Type ◽  
Nanoscale Topography ◽  
Key Microorganisms ◽  
Financial Losses

ABSTRACTAttachment and biofilm formation by bacterial pathogens on surfaces in natural, industrial, and hospital settings lead to infections and illnesses and even death. Minimizing bacterial attachment to surfaces using controlled topography could reduce the spreading of pathogens and, thus, the incidence of illnesses and subsequent human and financial losses. In this context, the attachment of key microorganisms, includingEscherichia coli,Listeria innocua, andPseudomonas fluorescens, to silica and alumina surfaces with micron and nanoscale topography was investigated. The results suggest that orientation of the attached cells occurs preferentially such as to maximize their contact area with the surface. Moreover, the bacterial cells exhibited different morphologies, including different number and size of cellular appendages, depending on the topographical details of the surface to which they attached. This suggests that bacteria may utilize different mechanisms of attachment in response to surface topography. These results are important for the design of novel microbe-repellant materials.

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 Flagellar stators stimulate c-di-GMP production by Pseudomonas aeruginosa

2018 ◽  
Author(s):  
Amy E. Baker ◽  
Shanice S. Webster ◽  
Andreas Diepold ◽  
Sherry L. Kuchma ◽  
Eric Bordeleau ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Feedback Loop ◽  
Bacterial Cells ◽  
Diguanylate Cyclase ◽  
Flagellar Motility ◽  
Swarming Motility ◽  
Surface Attachment ◽  
Bidirectional Interactions ◽  
Gmp Production

AbstractFlagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. C-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here we show that just as c-di-GMP can influence the stators, stators can impact c-di-GMP levels. We demonstrate that the swarming motility-driving stator MotC physically interacts with the transmembrane region of the diguanylate cyclase SadC. Furthermore, we demonstrate that this interaction is capable of stimulating SadC activity. We propose a model by which the MotCD stator set interacts with SadC to stimulate c-di-GMP production in conditions not permissive to motility. This regulation implies a positive feedback loop in which c-di-GMP signaling events cause MotCD stators to disengage from the motor; then disengaged stators stimulate c-di-GMP production to reinforce a biofilm mode of growth. Our studies help define the bidirectional interactions between c-di-GMP and the motility machinery.Importance.The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a non-motile, biofilm lifestyle. Recent studies have clearly demonstrated the ability of c-di-GMP to control motility via a number of mechanisms, including through controlling transcription of motility-related genes and modulating motor function. Here we provide evidence that motor components can in turn impact c-di-GMP levels. We propose that communication between motor components and c-di-GMP synthesis machinery allows the cell to have a robust and sensitive switching mechanism to control motility during early events in biofilm formation.

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