scholarly journals Coordination of Swarming Motility, Biosurfactant Synthesis, and Biofilm Matrix Exopolysaccharide Production in Pseudomonas aeruginosa

2014 ◽  
Vol 80 (21) ◽  
pp. 6724-6732 ◽  
Author(s):  
Shiwei Wang ◽  
Shan Yu ◽  
Zhenyin Zhang ◽  
Qing Wei ◽  
Lu Yan ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Bacterial Survival ◽  
Swarming Motility ◽  
Content Type ◽  
Exopolysaccharide Production ◽  
Complex Process ◽  
Exopolysaccharide Biosynthesis ◽  
Biofilm Matrix

ABSTRACTBiofilm formation is a complex process in which many factors are involved. Bacterial swarming motility and exopolysaccharides both contribute to biofilm formation, yet it is unclear how bacteria coordinate swarming motility and exopolysaccharide production. Psl and Pel are two key biofilm matrix exopolysaccharides inPseudomonas aeruginosa. This opportunistic pathogen has three types of motility, swimming, twitching, and swarming. In this study, we found that elevated Psl and/or Pel production reduced the swarming motility ofP. aeruginosabut had little effect on swimming and twitching. The reduction was due to decreased rhamnolipid production with no relation to the transcription ofrhlAB, two key genes involved in the biosynthesis of rhamnolipids. Rhamnolipid-negativerhlRandrhlABmutants synthesized more Psl, whereas exopolysaccharide-deficient strains exhibited a hyperswarming phenotype. These results suggest that competition for common sugar precursors catalyzed by AlgC could be a tactic forP. aeruginosato balance the synthesis of exopolysaccharides and rhamnolipids and to control bacterial motility and biofilm formation inversely because the biosynthesis of rhamnolipids, Psl, and Pel requires AlgC to provide the sugar precursors and an additionalalgCgene enhances the biosynthesis of Psl and rhamnolipids. In addition, our data indicate that the increase in RhlI/RhlR expression attenuated Psl production. This implied that the quorum-sensing signals could regulate exopolysaccharide biosynthesis indirectly in bacterial communities. In summary, this study represents a mechanism that bacteria utilize to coordinate swarming motility, biosurfactant synthesis, and biofilm matrix exopolysaccharide production, which is critical for biofilm formation and bacterial survival in the environment.

scholarly journals Clustered Regularly Interspaced Short Palindromic Repeat-Dependent, Biofilm-Specific Death of Pseudomonas aeruginosa Mediated by Increased Expression of Phage-Related Genes

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Gary E. Heussler ◽  
Kyle C. Cady ◽  
Katja Koeppen ◽  
Sabin Bhuju ◽  
Bruce A. Stanton ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Adaptive Immune System ◽  
Opportunistic Pathogen ◽  
Swarming Motility ◽  
Content Type ◽  
Minimal Impact ◽  
Crispr System ◽  
Alternative Function

ABSTRACTTheclusteredregularlyinterspacedshortpalindromicrepeat (CRISPR)/CRISPR-associated (CRISPR/Cas) system is an adaptive immune system present in many archaea and bacteria. CRISPR/Cas systems are incredibly diverse, and there is increasing evidence of CRISPR/Cas systems playing a role in cellular functions distinct from phage immunity. Previously, our laboratory reported one such alternate function in which the type 1-F CRISPR/Cas system of the opportunistic pathogenPseudomonas aeruginosastrain UCBPP-PA14 (abbreviated asP. aeruginosaPA14) inhibits both biofilm formation and swarming motility when the bacterium is lysogenized by the bacteriophage DMS3. In this study, we demonstrated that the presence of just the DMS3 protospacer and the protospacer-adjacent motif (PAM) on theP. aeruginosagenome is necessary and sufficient for this CRISPR-dependent loss of these group behaviors, with no requirement of additional DMS3 sequences. We also demonstrated that the interaction of the CRISPR system with the DMS3 protospacer induces expression of SOS-regulated phage-related genes, including the well-characterized pyocin operon, through the activity of the nuclease Cas3 and subsequent RecA activation. Furthermore, our data suggest that expression of the phage-related genes results in bacterial cell death on a surface due to the inability of the CRISPR-engaged strain to downregulate phage-related gene expression, while these phage-related genes have minimal impact on growth and viability under planktonic conditions. Deletion of the phage-related genes restores biofilm formation and swarming motility while still maintaining a functional CRISPR/Cas system, demonstrating that the loss of these group behaviors is an indirect effect of CRISPR self-targeting.IMPORTANCEThe various CRISPR/Cas systems found in both archaea and bacteria are incredibly diverse, and advances in understanding the complex mechanisms of these varied systems has not only increased our knowledge of host-virus interplay but has also led to a major advancement in genetic engineering. Recently, increasing evidence suggested that bacteria can co-opt the CRISPR system for functions besides adaptive immunity to phage infection. This study examined one such alternative function, and this report describes the mechanism of type 1-F CRISPR-dependent loss of the biofilm and swarming in the medically relevant opportunistic pathogenPseudomonas aeruginosa. Since both biofilm formation and swarming motility are important in the virulence ofP. aeruginosa, a full understanding of how the CRISPR system can regulate such group behaviors is fundamental to developing new therapeutics.

scholarly journals σ Factor and Anti-σ Factor That Control Swarming Motility and Biofilm Formation in Pseudomonas aeruginosa

2015 ◽  
Vol 198 (5) ◽  
pp. 755-765 ◽  
Author(s):  
Bryan A. McGuffie ◽  
Isabelle Vallet-Gely ◽  
Simon L. Dove
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Cell Envelope ◽  
Opportunistic Pathogen ◽  
Chronic Infections ◽  
Swarming Motility ◽  
Content Type ◽  
Σ Factor ◽  
Stress Response System

ABSTRACTPseudomonas aeruginosais capable of causing a variety of acute and chronic infections. Here, we provide evidence thatsbrR(PA2895), a gene previously identified as required during chronicP. aeruginosarespiratory infection, encodes an anti-σ factor that inhibits the activity of its cognate extracytoplasmic-function σ factor, SbrI (PA2896). Bacterial two-hybrid analysis identified an N-terminal region of SbrR that interacts directly with SbrI and that was sufficient for inhibition of SbrI-dependent gene expression. We show that SbrI associates with RNA polymerasein vivoand identify the SbrIR regulon. In cells lacking SbrR, the SbrI-dependent expression ofmuiAwas found to inhibit swarming motility and promote biofilm formation. Our findings reveal SbrR and SbrI as a novel set of regulators of swarming motility and biofilm formation inP. aeruginosathat mediate their effects throughmuiA, a gene not previously known to influence surface-associated behaviors in this organism.IMPORTANCEThis study characterizes a σ factor/anti-σ factor system that reciprocally regulates the surface-associated behaviors of swarming motility and biofilm formation in the opportunistic pathogenPseudomonas aeruginosa. We present evidence that SbrR is an anti-σ factor specific for its cognate σ factor, SbrI, and identify the SbrIR regulon inP. aeruginosa. We find that cells lacking SbrR are severely defective in swarming motility and exhibit enhanced biofilm formation. Moreover, we identifymuiA(PA1494) as the SbrI-dependent gene responsible for mediating these effects. SbrIR have been implicated in virulence and in responding to antimicrobial and cell envelope stress. SbrIR may therefore represent a stress response system that influences the surface behaviors ofP. aeruginosaduring infection.

scholarly journals Effect of Nitroxides on Swarming Motility and Biofilm Formation, Multicellular Behaviors in Pseudomonas aeruginosa

2013 ◽  
Vol 57 (10) ◽  
pp. 4877-4881 ◽  
Author(s):  
César de la Fuente-Núñez ◽  
Fany Reffuveille ◽  
Kathryn E. Fairfull-Smith ◽  
Robert E. W. Hancock
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Wild Type ◽  
Planktonic Cells ◽  
Swarming Motility ◽  
Content Type ◽  
Exogenous Addition ◽  
Biofilm Dispersion ◽  
Dispersal Activity

ABSTRACTThe ability of nitric oxide (NO) to induce biofilm dispersion has been well established. Here, we investigated the effect of nitroxides (sterically hindered nitric oxide analogues) on biofilm formation and swarming motility inPseudomonas aeruginosa. A transposon mutant unable to produce nitric oxide endogenously (nirS) was deficient in swarming motility relative to the wild type and the complemented strain. Moreover, expression of thenirSgene was upregulated by 9.65-fold in wild-type swarming cells compared to planktonic cells. Wild-type swarming levels were substantially restored upon the exogenous addition of nitroxide containing compounds, a finding consistent with the hypothesis that NO is necessary for swarming motility. Here, we showed that nitroxides not only mimicked the dispersal activity of NO but also prevented biofilms from forming in flow cell chambers. In addition, anirStransposon mutant was deficient in biofilm formation relative to the wild type and the complemented strain, thus implicating NO in the formation of biofilms. Intriguingly, despite its stand-alone action in inhibiting biofilm formation and promoting dispersal, a nitroxide partially restored the ability of anirSmutant to form biofilms.

scholarly journals Pseudomonas aeruginosa Requires the DNA-Specific Endonuclease EndA To Degrade Extracellular Genomic DNA To Disperse from the Biofilm

2019 ◽  
Vol 201 (18) ◽  
Author(s):  
Kathryn E. Cherny ◽  
Karin Sauer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Genomic Dna ◽  
Early Stage ◽  
Content Type ◽  
Biofilm Dispersion ◽  
Biofilm Structure ◽  
First Time ◽  
Biofilm Matrix ◽  
Dispersed Cells

ABSTRACT The dispersion of biofilms is an active process resulting in the release of planktonic cells from the biofilm structure. While much is known about the process of dispersion cue perception and the subsequent modulation of the c-di-GMP pool, little is known about subsequent events resulting in the release of cells from the biofilm. Given that dispersion coincides with void formation and an overall erosion of the biofilm structure, we asked whether dispersion involves degradation of the biofilm matrix. Here, we focused on extracellular genomic DNA (eDNA) due to its almost universal presence in the matrix of biofilm-forming species. We identified two probable nucleases, endA and eddB, and eddA encoding a phosphatase that were significantly increased in transcript abundance in dispersed cells. However, only inactivation of endA but not eddA or eddB impaired dispersion by Pseudomonas aeruginosa biofilms in response to glutamate and nitric oxide (NO). Heterologously produced EndA was found to be secreted and active in degrading genomic DNA. While endA inactivation had little effect on biofilm formation and the presence of eDNA in biofilms, eDNA degradation upon induction of dispersion was impaired. In contrast, induction of endA expression coincided with eDNA degradation and resulted in biofilm dispersion. Thus, released cells demonstrated a hyperattaching phenotype but remained as resistant to tobramycin as biofilm cells from which they egress, indicating EndA-dispersed cells adopted some but not all of the phenotypes associated with dispersed cells. Our findings indicate for the first time a role of DNase EndA in dispersion and suggest weakening of the biofilm matrix is a requisite for biofilm dispersion. IMPORTANCE The finding that exposure to DNase I impairs biofilm formation or leads to the dispersal of early stage biofilms has led to the realization of extracellular genomic DNA (eDNA) as a structural component of the biofilm matrix. However, little is known about the contribution of intrinsic DNases to the weakening of the biofilm matrix and dispersion of established biofilms. Here, we demonstrate for the first time that nucleases are induced in dispersed Pseudomonas aeruginosa cells and are essential to the dispersion response and that degradation of matrix eDNA by endogenously produced/secreted EndA is required for P. aeruginosa biofilm dispersion. Our findings suggest that dispersing cells mediate their active release from the biofilm matrix via the induction of nucleases.

scholarly journals PQS Produced by the Pseudomonas aeruginosa Stress Response Repels Swarms Away from Bacteriophage and Antibiotics

2019 ◽  
Vol 201 (23) ◽  
Author(s):  
Jean-Louis Bru ◽  
Brandon Rawson ◽  
Calvin Trinh ◽  
Katrine Whiteson ◽  
Nina Molin Høyland-Kroghsbo ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Stress Response ◽  
Antibiotic Treatment ◽  
Bacterial Pathogen ◽  
Warning Signal ◽  
Opportunistic Pathogen ◽  
Evolutionary Strategy ◽  
Swarming Motility ◽  
Content Type ◽  
Bacteriophage Infection

ABSTRACT We investigate the effect of bacteriophage infection and antibiotic treatment on the coordination of swarming, a collective form of flagellum- and pilus-mediated motility in bacteria. We show that phage infection of the opportunistic bacterial pathogen Pseudomonas aeruginosa abolishes swarming motility in the infected subpopulation and induces the release of the Pseudomonas quinolone signaling molecule PQS, which repulses uninfected subpopulations from approaching the infected area. These mechanisms have the overall effect of limiting the infection to a subpopulation, which promotes the survival of the overall population. Antibiotic treatment of P. aeruginosa elicits the same response, abolishing swarming motility and repulsing approaching swarms away from the antibiotic-treated area through a PQS-dependent mechanism. Swarms are entirely repelled from the zone of antibiotic-treated P. aeruginosa, consistent with a form of antibiotic evasion, and are not repelled by antibiotics alone. PQS has multiple functions, including serving as a quorum-sensing molecule, activating an oxidative stress response, and regulating the release of virulence and host-modifying factors. We show that PQS serves additionally as a stress warning signal that causes the greater population to physically avoid cell stress. The stress response at the collective level observed here in P. aeruginosa is consistent with a mechanism that promotes the survival of bacterial populations. IMPORTANCE We uncover a phage- and antibiotic-induced stress response in the clinically important opportunistic pathogen Pseudomonas aeruginosa. Phage-infected P. aeruginosa subpopulations are isolated from uninfected subpopulations by the production of a stress-induced signal. Activation of the stress response by antibiotics causes P. aeruginosa to physically be repelled from the area containing antibiotics altogether, consistent with a mechanism of antibiotic evasion. The stress response observed here could increase P. aeruginosa resilience against antibiotic treatment and phage therapy in health care settings, as well as provide a simple evolutionary strategy to avoid areas containing stress.

scholarly journals Deletion Mutant Library for Investigation of Functional Outputs of Cyclic Diguanylate Metabolism in Pseudomonas aeruginosa PA14

2014 ◽  
Vol 80 (11) ◽  
pp. 3384-3393 ◽  
Author(s):  
Dae-Gon Ha ◽  
Megan E. Richman ◽  
George A. O'Toole
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Deletion Mutant ◽  
Deletion Mutants ◽  
Mutant Library ◽  
Potential Utility ◽  
Cyclic Diguanylate ◽  
Swarming Motility ◽  
Content Type ◽  
Swimming Motility

ABSTRACTWe constructed a library of in-frame deletion mutants targeting each gene inPseudomonas aeruginosaPA14 predicted to participate in cyclic di-GMP (c-di-GMP) metabolism (biosynthesis or degradation) to provide a toolkit to assist investigators studying c-di-GMP-mediated regulation by this microbe. We present phenotypic assessments of each mutant, including biofilm formation, exopolysaccharide (EPS) production, swimming motility, swarming motility, and twitch motility, as a means to initially characterize these mutants and to demonstrate the potential utility of this library.

scholarly journals Signal Sensing and Transduction Are Conserved between the Periplasmic Sensory Domains of BifA and SagS

mSphere ◽  
2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Jozef Dingemans ◽  
Rebecca E. Al-Feghali ◽  
Holger Sondermann ◽  
Karin Sauer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Structural Similarity ◽  
Opportunistic Pathogen ◽  
Sequence Conservation ◽  
Sensor Kinase ◽  
Antibiotic Tolerance ◽  
Bacterial Cells ◽  
Chronic Infections ◽  
Content Type

ABSTRACT The hybrid sensor kinase SagS of Pseudomonas aeruginosa plays a key role in the transition from the planktonic to the biofilm mode of growth. Recently, we have shown that distinct sets of residues in its periplasmic HmsP sensory domain are involved in the regulation of biofilm formation or antibiotic tolerance. Interestingly, the HmsP domain of the phosphodiesterase BifA shows great predicted structural similarity to that of SagS, despite moderate sequence conservation and only a number of residues involved in SagS signaling being conserved between both proteins. Based on this observation, we hypothesized that BifA and SagS may use similar mechanisms to sense and transduce signals perceived at their periplasmic HmsP domains and, therefore, may be interchangeable. To test this hypothesis, we constructed SagS hybrids in which the HmsP domain of SagS was replaced by that of BifA (and vice versa) or by the DISMED2 sensory domain of NicD. The SagS-BifA hybrid restored attachment and biofilm formation by the ΔbifA mutant. Likewise, while the NicD-SagS hybrid was nonfunctional, the BifA-SagS hybrid partially restored pathways leading to biofilm formation and antibiotic tolerance in a ΔsagS mutant background. Furthermore, alanine substitution of key residues previously associated with the biofilm formation and antibiotic tolerance pathways of SagS impaired signal transduction by the BifA-SagS hybrid in a similar way to SagS. In conclusion, our data indicate that the nature of the sensory domain is important for proper functionality of the cytoplasmic effector domains and that signal sensing and transduction are likely conserved in SagS and BifA. IMPORTANCE Biofilms have been associated with more than 60% of all recalcitrant and chronic infections and can render bacterial cells up to a thousand times more resistant to antibiotics than planktonic cells. Although it is known that the transition from the planktonic to the biofilm mode of growth involves two-component regulatory systems, increased c-di-GMP levels, and quorum sensing systems among others, the exact signaling events that lead to biofilm formation remain unknown. In the opportunistic pathogen Pseudomonas aeruginosa, the hybrid sensor kinase SagS regulates biofilm formation and antibiotic tolerance through two independent pathways via distinct residues in its periplasmic sensory domain. Interestingly, the sensory domains of SagS and BifA show great predicted structural similarity despite moderate sequence conservation. Here we show that the sensory domains of BifA and SagS are functionally interchangeable and that they use a similar mechanism of signal sensing and transduction, which broadens our understanding of how bacteria perceive and transduce signals when transitioning to the biofilm mode of growth.

scholarly journals Role of Intracellular Proteases in the Antibiotic Resistance, Motility, and Biofilm Formation of Pseudomonas aeruginosa

2011 ◽  
Vol 56 (2) ◽  
pp. 1128-1132 ◽  
Author(s):  
Lucía Fernández ◽  
Elena B. M. Breidenstein ◽  
Diana Song ◽  
Robert E. W. Hancock
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Biofilm Formation ◽  
Regulatory Networks ◽  
Swarming Motility ◽  
Content Type ◽  
Adverse Conditions ◽  
Related Proteins ◽  
Intracellular Proteases

ABSTRACTPseudomonas aeruginosapossesses complex regulatory networks controlling virulence and survival under adverse conditions, including antibiotic pressure, which are interconnected and share common regulatory proteins. Here, we screen a panel of 13 mutants defective in intracellular proteases and demonstrate that, in addition to the known alterations in Lon and AsrA mutants, mutation of three protease-related proteins PfpI, ClpS, and ClpP differentially affected antibiotic resistance, swarming motility, and biofilm formation.

scholarly journals PilZ Domain Protein FlgZ Mediates Cyclic Di-GMP-Dependent Swarming Motility Control in Pseudomonas aeruginosa

2016 ◽  
Vol 198 (13) ◽  
pp. 1837-1846 ◽  
Author(s):  
Amy E. Baker ◽  
Andreas Diepold ◽  
Sherry L. Kuchma ◽  
Jessie E. Scott ◽  
Dae Gon Ha ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Fluorescent Protein ◽  
Bacterial Species ◽  
Dependent Manner ◽  
Swarming Motility ◽  
Content Type ◽  
Bacterial Surface ◽  
Important Regulator ◽  
Green Fluorescent

ABSTRACTThe second messenger cyclic diguanylate (c-di-GMP) is an important regulator of motility in many bacterial species. InPseudomonas aeruginosa, elevated levels of c-di-GMP promote biofilm formation and repress flagellum-driven swarming motility. The rotation ofP. aeruginosa's polar flagellum is controlled by two distinct stator complexes, MotAB, which cannot support swarming motility, and MotCD, which promotes swarming motility. Here we show that when c-di-GMP levels are elevated, swarming motility is repressed by the PilZ domain-containing protein FlgZ and by Pel polysaccharide production. We demonstrate that FlgZ interacts specifically with the motility-promoting stator protein MotC in a c-di-GMP-dependent manner and that a functional green fluorescent protein (GFP)-FlgZ fusion protein shows significantly reduced polar localization in a strain lacking the MotCD stator. Our results establish FlgZ as a c-di-GMP receptor affecting swarming motility byP. aeruginosaand support a model wherein c-di-GMP-bound FlgZ impedes motility via its interaction with the MotCD stator.IMPORTANCEThe regulation of surface-associated motility plays an important role in bacterial surface colonization and biofilm formation. c-di-GMP signaling is a widespread means of controlling bacterial motility, and yet the mechanism whereby this signal controls surface-associated motility inP. aeruginosaremains poorly understood. Here we identify a PilZ domain-containing c-di-GMP effector protein that contributes to c-di-GMP-mediated repression of swarming motility byP. aeruginosa. We provide evidence that this effector, FlgZ, impacts swarming motility via its interactions with flagellar stator protein MotC. Thus, we propose a new mechanism for c-di-GMP-mediated regulation of motility for a bacterium with two flagellar stator sets, increasing our understanding of surface-associated behaviors, a key prerequisite to identifying ways to control the formation of biofilm communities.

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