scholarly journals A pivotal role for the response regulator DegU in controlling multicellular behaviour

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ewan J. Murray ◽  
Taryn B. Kiley ◽  
Nicola R. Stanley-Wall
Keyword(s):  
Cell Fate ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Response Regulator ◽  
Regulatory System ◽  
Environmental Cues ◽  
Swarming Motility ◽  
Food Borne ◽  
Novel Targets ◽  
Complex Regulatory Network

Bacteria control multicellular behavioural responses, including biofilm formation and swarming motility, by integrating environmental cues through a complex regulatory network. Heterogeneous gene expression within an otherwise isogenic cell population that allows for differentiation of cell fate is an intriguing phenomenon that adds to the complexity of multicellular behaviour. This review focuses on recent data about how DegU, a pleiotropic response regulator, co-ordinates multicellular behaviour in Bacillus subtilis. We review studies that challenge the conventional understanding of the molecular mechanisms underpinning the DegU regulatory system and others that describe novel targets of DegU during activation of biofilm formation by B. subtilis. We also discuss a novel role for DegU in regulating multicellular processes in the food-borne pathogen Listeria monocytogenes.

scholarly journals Inhibition of Quorum Sensing in Serratia marcescens AS-1 by Synthetic Analogs of N-Acylhomoserine Lactone

2007 ◽  
Vol 73 (20) ◽  
pp. 6339-6344 ◽  
Author(s):  
Tomohiro Morohoshi ◽  
Toshitaka Shiono ◽  
Kiyomi Takidouchi ◽  
Masashi Kato ◽  
Norihiro Kato ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Serratia Marcescens ◽  
Biofilm Formation ◽  
Acyl Chain ◽  
Regulatory System ◽  
Homoserine Lactone ◽  
Signal Molecule ◽  
Swarming Motility ◽  
Gram Negative ◽  
Acylhomoserine Lactone

ABSTRACT Quorum sensing is a regulatory system for controlling gene expression in response to increasing cell density. N-Acylhomoserine lactone (AHL) is produced by gram-negative bacteria, which use it as a quorum-sensing signal molecule. Serratia marcescens is a gram-negative opportunistic pathogen which is responsible for an increasing number of serious nosocomial infections. S. marcescens AS-1 produces N-hexanoyl homoserine lactone (C6-HSL) and N-(3-oxohexanoyl) homoserine lactone and regulates prodigiosin production, swarming motility, and biofilm formation by AHL-mediated quorum sensing. We synthesized a series of N-acyl cyclopentylamides with acyl chain lengths ranging from 4 to 12 and estimated their inhibitory effects on prodigiosin production in AS-1. One of these molecules, N-nonanoyl-cyclopentylamide (C9-CPA), had a strong inhibitory effect on prodigiosin production. C9-CPA also inhibited the swarming motility and biofilm formation of AS-1. A competition assay revealed that C9-CPA was able to inhibit quorum sensing at four times the concentration of exogenous C6-HSL and was more effective than the previously reported halogenated furanone. Our results demonstrated that C9-CPA was an effective quorum-sensing inhibitor for S. marcescens AS-1.

scholarly journals Hik36–Hik43 and Rre6 act as a two-component regulatory system to control cell aggregation in Synechocystis sp. PCC6803

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kota Kera ◽  
Yuichiro Yoshizawa ◽  
Takehiro Shigehara ◽  
Tatsuya Nagayama ◽  
Masaru Tsujii ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Morphological Changes ◽  
Response Regulator ◽  
Control Cell ◽  
Regulatory System ◽  
Cell Aggregation ◽  
Wild Type ◽  
Type Iv ◽  
Two Component ◽  
In The Wild

Abstract In response to environmental stress the model cyanobacterium, Synechocystis sp. PCC6803 can switch from a planktonic state to autoaggregation and biofilm formation. The precise mechanism of this transition remains unknown. Here we investigated the role of a candidate two-component regulatory system (TCS) in controlling morphological changes, as a way to understand the intermediate molecular steps that are part of the signaling pathway. A bacterial two-hybrid assay showed that the response regulator Rre6 formed a TCS together with a split histidine kinase consisting of Hik36 and Hik43. Individual disruption mutants displayed autoaggregation in a static culture. In contrast, unlike in the wild type, high salinity did not induce biofilm formation in Δhik36, Δhik43 and Δrre6. The expression levels of exopolysaccharide (EPS) production genes were higher in Δhik36 and Δhik43, compared with the wild type, but lower in Δrre6, suggesting that the TCS regulated EPS production in Synechocystis. Rre6 interacted physically with the motor protein PilT2, that is a component of the type IV pilus system. This interaction was enhanced in a phosphomimic version of Rre6. Taken together, Hik36–Hik43–Rre6 function as an upstream component of the pili-related signal transduction cascade and control the prevention of cell adhesion and biofilm formation.

scholarly journals Polymyxin B Resistance and Biofilm Formation in Vibrio cholerae Are Controlled by the Response Regulator CarR

2015 ◽  
Vol 83 (3) ◽  
pp. 1199-1209 ◽  
Author(s):  
Kivanc Bilecen ◽  
Jiunn C. N. Fong ◽  
Andrew Cheng ◽  
Christopher J. Jones ◽  
David Zamorano-Sánchez ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Lipid A ◽  
Response Regulator ◽  
Regulatory Region ◽  
Regulatory System ◽  
Polymyxin B ◽  
Content Type ◽  
Two Component ◽  
Antimicrobial Peptide Resistance

Two-component systems play important roles in the physiology of many bacterial pathogens.Vibrio cholerae's CarRS two-component regulatory system negatively regulates expression ofvps(Vibriopolysaccharide) genes and biofilm formation. In this study, we report that CarR confers polymyxin B resistance by positively regulating expression of thealmEFGgenes, whose products are required for glycine and diglycine modification of lipid A. We determined that CarR directly binds to the regulatory region of thealmEFGoperon. Similarly to acarRmutant, strains lackingalmE,almF, andalmGexhibited enhanced polymyxin B sensitivity. We also observed that strains lackingalmEor thealmEFGoperon have enhanced biofilm formation. Our results reveal that CarR regulates biofilm formation and antimicrobial peptide resistance inV. cholerae.

scholarly journals The prevalence and origin of exoprotease-producing cells in the Bacillus subtilis biofilm

Microbiology ◽  
2014 ◽  
Vol 160 (1) ◽  
pp. 56-66 ◽  
Author(s):  
Victoria L. Marlow ◽  
Francesca R. Cianfanelli ◽  
Michael Porter ◽  
Lynne S. Cairns ◽  
J. Kim Dale ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Biofilm Formation ◽  
Single Cell Analysis ◽  
Response Regulator ◽  
Cell Types ◽  
Cell Analysis ◽  
Swarming Motility ◽  
Specialized Cell ◽  
Differentiated Cells ◽  
First Time

Biofilm formation by the Gram-positive bacterium Bacillus subtilis is tightly controlled at the level of transcription. The biofilm contains specialized cell types that arise from controlled differentiation of the resident isogenic bacteria. DegU is a response regulator that controls several social behaviours exhibited by B. subtilis including swarming motility, biofilm formation and extracellular protease (exoprotease) production. Here, for the first time, we examine the prevalence and origin of exoprotease-producing cells within the biofilm. This was accomplished using single-cell analysis techniques including flow cytometry and fluorescence microscopy. We established that the number of exoprotease-producing cells increases as the biofilm matures. This is reflected by both an increase at the level of transcription and an increase in exoprotease activity over time. We go on to demonstrate that exoprotease-producing cells arise from more than one cell type, namely matrix-producing and non-matrix-producing cells. In toto these findings allow us to add exoprotease-producing cells to the list of specialized cell types that are derived during B. subtilis biofilm formation and furthermore the data highlight the plasticity in the origin of differentiated cells.

scholarly journals Regulation of bacterial surface attachment by a network of sensory transduction proteins

2019 ◽  
Author(s):  
Leila M. Reyes Ruiz ◽  
Aretha Fiebig ◽  
Sean Crosson
Keyword(s):  
Transcription Factors ◽  
Caulobacter Crescentus ◽  
Response Regulator ◽  
Genetic Selection ◽  
Regulatory System ◽  
Sensory Transduction ◽  
Environmental Cues ◽  
Bacterial Cells ◽  
Natural Ecosystems ◽  
Bacterial Surface

AbstractBacteria are often attached to surfaces in natural ecosystems. A surface-associated lifestyle can have advantages, but shifts in the physiochemical state of the environment may result in conditions in which attachment has a negative fitness impact. Therefore, bacterial cells employ numerous mechanisms to control the transition from an unattached to a sessile state. TheCaulobacter crescentusprotein HfiA is a potent developmental inhibitor of the secreted polysaccharide adhesin known as the holdfast, which enables permanent attachment to surfaces. Multiple environmental cues influence expression ofhfiA, but mechanisms ofhfiAregulation remain largely undefined. Through a forward genetic selection, we have discovered a multi-gene network encoding a suite of two-component system (TCS) proteins and transcription factors that coordinately controlhfiAtranscription and surface adhesion. The hybrid HWE-family histidine kinase, SkaH, is central among these regulators and forms heteromeric complexes with the kinases, LovK and SpdS. The response regulator SpdR indirectly inhibitshfiAexpression by activating two XRE-family transcription factors that directly bind thehfiApromoter to repress its transcription. This study provides evidence for a model in which a consortium of environmental sensors and transcriptional regulators integrate environmental cues at thehfiApromoter to control the attachment decision.Author summaryLiving on a surface within a community of cells confers a number of advantages to a bacterium. However, the transition from a free-living state to a surface-attached lifestyle should be tightly regulated to ensure that cells avoid adhering to toxic or resource-limited niches. Many bacteria build adhesive structures at their surfaces that enable attachment. We sought to discover genes that control development of theCaulobacter crescentussurface adhesin known as the holdfast. Our studies uncovered a network of signal transduction proteins that coordinately control the biosynthesis of the holdfast by regulating transcription of the holdfast inhibitor,hfiA. We conclude thatC. crescentususes a multi-component regulatory system to sense and integrate environmental information to determine whether to attach to a surface, or to remain in an unattached state.

scholarly journals Identification of LuxR Family Regulators That Integrate Into Quorum Sensing Circuit in Vibrio parahaemolyticus

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaojun Zhong ◽  
Ranran Lu ◽  
Fuwen Liu ◽  
Jinjie Ye ◽  
Junyang Zhao ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Biofilm Formation ◽  
Vibrio Parahaemolyticus ◽  
Wide Spectrum ◽  
Cell Communication ◽  
Systematic Research ◽  
Global Regulator ◽  
Food Borne ◽  
Reporter Assays ◽  
Complex Regulatory Network

Vibrio parahaemolyticus is one of the most important food-borne pathogens that cause economic and public health problems worldwide. Quorum sensing (QS) is a way for the cell-cell communication between bacteria that controls a wide spectrum of processes and phenotypic behaviors. In this study, we performed a systematic research of LuxR family regulators in V. parahaemolyticus and found that they influence the bacterial growth and biofilm formation. We then established a QS reporter plasmid based on bioluminescence luxCDABE operon of Vibrio harveyi and demonstrated that several LuxR family regulators integrated into QS circuit in V. parahaemolyticus. Thereinto, a novel LuxR family regulator, named RobA, was identified as a global regulator by RNA-sequencing analyses, which affected the transcription of 515 genes in V. parahaemolyticus. Subsequent studies confirmed that RobA regulated the expression of the exopolysaccharides (EPS) synthesis cluster and thus controlled the biofilm formation. In addition, bioluminescence reporter assays showed that RobA plays a key role in the QS circuit by regulating the expression of opaR, aphA, cpsQ-mfpABC, cpsS, and scrO. We further demonstrated that the regulation of RobA to EPS and MfpABC depended on OpaR and CpsQ, which combined the QS signal with bis-(3′-5′)-cyclic dimeric GMP to construct a complex regulatory network of biofilm formation. Our data provided new insights into the bacterial QS mechanisms and biofilm formation in V. parahaemolyticus.

scholarly journals Structural Basis for DNA Recognition by the Two-Component Response Regulator RcsB

mBio ◽  
2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Ekaterina V. Filippova ◽  
Bozena Zemaitaitis ◽  
Theint Aung ◽  
Alan J. Wolfe ◽  
Wayne F. Anderson
Keyword(s):  
Dna Sequences ◽  
Biofilm Formation ◽  
Molecular Mechanisms ◽  
Response Regulator ◽  
Structural Basis ◽  
Oligomeric State ◽  
Link Type ◽  
The Family ◽  
Two Component ◽  
Bacterial Genes

ABSTRACT RcsB is a highly conserved transcription regulator of the Rcs phosphorelay system, a complex two-component signal transduction system (N. Majdalani and S. Gottesman, Annu Rev Microbiol 59:379–405, 2005; A. J. Wolfe, Curr Opin Microbiol 13:204–209, 2010, https://doi.org/10.1016/j.mib.2010.01.002; D. J. Clarke, Future Microbiol 5:1173–1184, 2010, https://doi.org/10.2217/fmb.10.83). RcsB plays an important role in virulence and pathogenicity in human hosts by regulating biofilm formation. RcsB can regulate transcription alone or together with its auxiliary transcription regulators by forming heterodimers. This complexity allows RcsB to regulate transcription of more than 600 bacterial genes in response to different stresses (D. Wang et al., Mol Plant Microbe Interact 25:6–17, 2012, https://doi.org/10.1094/MPMI-08-11-0207). Despite increasing knowledge of RcsB importance, molecular mechanisms that drive the ability of RcsB to control transcription of a large number of genes remain unclear. Here, we present crystal structures of unphosphorylated RcsB in complex with the consensus DNA-binding sequence of 22-mer (DNA22) and 18-mer (DNA18) of the flhDC operon from Escherichia coli determined at 3.15- and 3.37-Å resolution, respectively. The results of our structural analysis combined with the results of in vitro binding assays provide valuable insights to the protein regulatory mechanism, demonstrate how RcsB recognizes target DNA sequences, and reveal a unique oligomeric state that allows RcsB to form homo- and heterodimers. This information will help us understand the complex mechanisms of transcriptional regulation by RcsB in bacteria. IMPORTANCE RcsB is a well-studied two-component response regulator of the Rcs phosphorelay system, conserved within the family Enterobacteriaceae, which includes many pathogens. It is a global regulator, controlling more than 5% of bacterial genes associated with capsule biosynthesis, flagellar biogenesis, cell wall biosynthesis, antibiotic resistance, biofilm formation, and virulence in pathogens. Knowledge of RcsB structure represents a unique opportunity to explore mechanisms that regulate the Rcs phosphorelay system and its role in the family Enterobacteriaceae.

scholarly journals ResDE-Dependent Regulation of Enterotoxin Gene Expression in Bacillus cereus: Evidence for Multiple Modes of Binding for ResD and Interaction with Fnr

2009 ◽  
Vol 191 (13) ◽  
pp. 4419-4426 ◽  
Author(s):  
Julia Esbelin ◽  
Jean Armengaud ◽  
Assia Zigha ◽  
Catherine Duport
Keyword(s):  
Bacillus Cereus ◽  
Response Regulator ◽  
Regulatory System ◽  
Molecular Evidence ◽  
Promoter Regions ◽  
Food Borne ◽  
Regulator Genes ◽  
Hemolysin Bl

ABSTRACT In the food-borne pathogen Bacillus cereus F4430/73, the production of major virulence factors hemolysin BL (Hbl) and nonhemolytic enterotoxin (Nhe) is regulated through complex mechanisms. The two-component regulatory system ResDE is involved in the activation of hbl and nhe transcription. Here, the response regulator ResD and the sensor kinase ResE were overexpressed and purified, and autophosphorylation of ResE and transphosphorylation of ResD by ResE were demonstrated in vitro. ResD is mainly monomeric in solution, regardless of its phosphorylation state. ResD was shown to interact directly with promoter regions (p) of the enterotoxin regulator genes resDE, fnr, and plcR and the enterotoxin structural genes nhe and hbl, but with different affinities. Binding of ResD to pplcR, pnhe, and phbl was not dependent on the ResD phosphorylation status. In contrast, ResD phosphorylation significantly increased interactions between ResD and presDE and pfnr. Taken together, these results showed that phosphorylation of ResD results in a different target expression pattern. Furthermore, ResD and the redox activator Fnr were found to physically interact and simultaneously bind their target DNAs. We propose that unphosphorylated ResD acts as an antiactivator of Fnr, while phosphorylated ResD acts as a coactivator of Fnr. Finally, our findings represent the first molecular evidence of the role of ResDE as a sentinel system capable of sensing redox changes and coordinating a response that modulates B. cereus virulence.

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 The horizontally-acquired response regulator SsrB drives a Salmonella lifestyle switch by relieving biofilm silencing

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Stuti K Desai ◽  
Ricksen S Winardhi ◽  
Saravanan Periasamy ◽  
Michal M Dykas ◽  
Yan Jie ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Virulence Genes ◽  
Response Regulator ◽  
Regulatory System ◽  
Systemic Infection ◽  
Transcriptional Regulator ◽  
Carrier State ◽  
Present Evidence ◽  
Two Component ◽  
Common Strategy

A common strategy by which bacterial pathogens reside in humans is by shifting from a virulent lifestyle, (systemic infection), to a dormant carrier state. Two major serovars of Salmonella enterica, Typhi and Typhimurium, have evolved a two-component regulatory system to exist inside Salmonella-containing vacuoles in the macrophage, as well as to persist as asymptomatic biofilms in the gallbladder. Here we present evidence that SsrB, a transcriptional regulator encoded on the SPI-2 pathogenicity-island, determines the switch between these two lifestyles by controlling ancestral and horizontally-acquired genes. In the acidic macrophage vacuole, the kinase SsrA phosphorylates SsrB, and SsrB~P relieves silencing of virulence genes and activates their transcription. In the absence of SsrA, unphosphorylated SsrB directs transcription of factors required for biofilm formation specifically by activating csgD (agfD), the master biofilm regulator by disrupting the silenced, H-NS-bound promoter. Anti-silencing mechanisms thus control the switch between opposing lifestyles.

Sign in / Sign up

Export Citation Format

Share Document