scholarly journals Modulation of Flagellar Rotation in Surface-Attached Bacteria: A Circuit for Rapid Surface-Sensing

2019 ◽  
Author(s):  
Maren Schniederberend ◽  
Jessica F. Johnston ◽  
Emilee Shine ◽  
Cong Shen ◽  
Ruchi Jain ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Second Messenger ◽  
Switching Behavior ◽  
Scaffolding Protein ◽  
Polar Flagellum ◽  
Initial Contact ◽  
Surface Attachment ◽  
Attached Bacteria ◽  
Flagellar Rotation

AbstractAttachment is a necessary first step in bacterial commitment to surface-associated behaviors that include colonization, biofilm formation, and host-directed virulence. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa can initially attach to surfaces via its single polar flagellum. Although many bacteria quickly detach, some become irreversibly attached and express surface-associated structures, such as Type IV pili, and behaviors, including twitching motility and biofilm initiation. P. aeruginosa that lack the GTPase FlhF assemble a randomly placed flagellum that is motile; however, we observed that these mutant bacteria show defects in biofilm formation comparable to those seen for non-motile, aflagellate bacteria. This phenotype was associated with altered behavior of ΔflhF bacteria immediately following surface-attachment. Forward and reverse genetic screens led to the discovery that FlhF interacts with FimV to control flagellar rotation at a surface, and implicated cAMP signaling in this pathway. Although cAMP controls many transcriptional programs in P. aeruginosa, the known targets of this second messenger were not required to modulate flagellar rotation in surface-attached bacteria. Instead, alterations in switching behavior of the motor appear to result from previously undescribed effects of cAMP on switch complex proteins and/or the motor-stators associated with them.Author SummaryAttachment to a surface often triggers programs of gene expression that alter the behavior, virulence and fitness of bacteria. Initial contact is usually mediated by surface exposed adhesins, such as flagella or pili/fimbriae, and there is much interest in how these structures might sense and respond to surface attachment. The human bacterial pathogen Pseudomonas aeruginosa usually contacts surfaces via its polar flagellum, the rotary motor that also powers bacterial swimming. We observed that wild-type bacteria quickly stopped rotating their flagellum after surface attachment, but that a mutant lacking the flagellar-associated protein FlhF did not. Using a combination of genetic approaches, we demonstrated that FlhF interacts with a component of the flagellar rotor (FliG) and with a polar scaffolding protein that positively regulates cAMP production (FimV) to stop flagellar rotation and thereby favor bacterial persistence at a surface. We provide evidence that the second messenger cAMP is the likely signal generated by flagellar-mediated surface attachment and show that cAMP is sufficient to alter the behavior of the flagellar motor.

scholarly journals Induction of native c-di-GMP phosphodiesterases leads to dispersal of Pseudomonas aeruginosa biofilms

2021 ◽  
Author(s):  
Jens Bo Andersen ◽  
Kasper Nørskov Kragh ◽  
Louise Dahl Hultqvist ◽  
Morten Rybtke ◽  
Martin Nilsson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Single Cell ◽  
Biofilm Formation ◽  
Ectopic Expression ◽  
Second Messenger ◽  
Flow Cell ◽  
Diguanylate Cyclases ◽  
Biofilm Dispersal ◽  
High Level

A decade of research has shown that the molecule c-di-GMP functions as a central second messenger in many bacteria. A high level of c-di-GMP is associated with biofilm formation whereas a low level of c-di-GMP is associated with a planktonic single-cell bacterial lifestyle. C-di-GMP is formed by diguanylate cyclases and is degraded by specific phosphodiesterases. We have previously presented evidence that ectopic expression in Pseudomonas aeruginosa of the Escherichia coli phosphodiesterase YhjH results in biofilm dispersal. More recently, however, evidence has been presented that induction of native c-di-GMP phosphodiesterases does not lead to dispersal of P. aeruginosa biofilms. The latter result may discourage attempts to use c-di-GMP signaling as a target for development of anti-biofilm drugs. However, here we demonstrate that induction of the P. aeruginosa c-di-GMP phosphodiesterases PA2133 and BifA indeed does result in dispersal of P. aeruginosa biofilms in both a microtiter tray biofilm assay and in a flow-cell biofilm system.

EFFECT OF TOPOGRAPHICALLY PATTERNED POLY(DIMETHYLSILOXANE) SURFACES ON Pseudomonas aeruginosa ADHESION AND BIOFILM FORMATION

Nano LIFE ◽  
2012 ◽  
Vol 02 (04) ◽  
pp. 1242004 ◽  
Author(s):  
JOHN F. LING ◽  
MARY V. GRAHAM ◽  
NATHANIEL C. CADY
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Lower Surface ◽  
Bacterial Attachment ◽  
Initial Surface ◽  
Direct Role ◽  
Surface Attachment ◽  
Bacterial Surface ◽  
Static Conditions

Bacterial pathogens, such as Pseudomonas aeruginosa, readily form biofilms on surfaces, limiting the efficacy of antimicrobial and antibiotic treatments. To mitigate biofilm formation, surfaces are often treated with antimicrobial agents, which have limited lifetime and efficacy. Recent studies have shown that well-ordered topographic patterns can limit bacterial attachment to surfaces and limit biofilm formation. In this study, nano and microscale patterned poly(dimethylsiloxane) surfaces were evaluated for their ability to affect adhesion and biofilm formation by Pseudomonas aeruginosa. Feature size and spacing were varied from 500 nm to 2 μm and included repeating arrays of square pillars, holes, lines and biomimetc Sharklet™ patterns. Bacterial surface adhesion and biofilm formation was assessed in microfluidic flow devices and under static conditions. Attachment profiles under static and fluid flow varied within topography types, sizes and spacing. Pillar structures of all sizes yielded lower surface attachment than line-based patterns and arrays of holes. This trend was also observed for biomimetic Sharklet™ patterns, with reduced bacterial attachment to "raised" features as compared to "recessed" features. Notably, none of the topographically patterned surfaces outperformed smooth surfaces (without topography) for resisting cell adhesion. Initial surface attachment patterns were indicative of subsequent biofilm formation and coverage, suggesting a direct role of surface topography in biofilm-based biofouling.

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.

scholarly journals Role of Cyclic Di-GMP and Exopolysaccharide in Type IV Pilus Dynamics

2017 ◽  
Vol 199 (8) ◽  
Author(s):  
Jan Ribbe ◽  
Amy E. Baker ◽  
Sebastian Euler ◽  
George A. O'Toole ◽  
Berenike Maier
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Molecular Motor ◽  
Type Iv Pili ◽  
Force Generation ◽  
Surface Attachment ◽  
Content Type ◽  
Type Iv ◽  
Critical Components ◽  
Planktonic State

ABSTRACT For Pseudomonas aeruginosa, levels of cyclic di-GMP (c-di-GMP) govern the transition from the planktonic state to biofilm formation. Type IV pili (T4P) are crucial determinants of biofilm structure and dynamics, but it is unknown how levels of c-di-GMP affect pilus dynamics. Here, we scrutinized how c-di-GMP affects molecular motor properties and adhesive behavior of T4P. By means of retraction, T4P generated forces of ∼30 pN. Deletion mutants in the proteins with known roles in biofilm formation, swarming motility, and exopolysaccharide (EPS) production (specifically, the diguanylate cyclases sadC and roeA or the c-di-GMP phosphodiesterase bifA) showed only modest effects on velocity or force of T4P retraction. At high levels of c-di-GMP, the production of exopolysaccharides, particularly of Pel, is upregulated. We found that Pel production strongly enhances T4P-mediated surface adhesion of P. aeruginosa, suggesting that T4P-matrix interactions may be involved in biofilm formation by P. aeruginosa. Finally, our data support the previously proposed model of slingshot-like “twitching” motility of P. aeruginosa. IMPORTANCE Type IV pili (T4P) play various important roles in the transition of bacteria from the planktonic state to the biofilm state, including surface attachment and surface sensing. Here, we investigate adhesion, dynamics, and force generation of T4P after bacteria engage a surface. Our studies showed that two critical components of biofilm formation by Pseudomonas aeruginosa, T4P and exopolysaccharides, contribute to enhanced T4P-mediated force generation by attached bacteria. These data indicate a crucial role for the coordinated impact of multiple biofilm-promoting factors during the early stages of attachment to a surface. Our data are also consistent with a previous model explaining why pilus-mediated motility in P. aeruginosa results in characteristic “twitching” behavior.

scholarly journals SadB Is Required for the Transition from Reversible to Irreversible Attachment during Biofilm Formation by Pseudomonas aeruginosa PA14

2004 ◽  
Vol 186 (14) ◽  
pp. 4476-4485 ◽  
Author(s):  
Nicky C. Caiazza ◽  
George A. O'Toole
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Unknown Function ◽  
Biofilm Formation ◽  
Planktonic Cells ◽  
Surface Attachment ◽  
Reading Frame ◽  
New Class ◽  
Transposon Insertion ◽  
Microbial Development ◽  
Mutant Cells

ABSTRACT Current models of biofilm formation by Pseudomonas aeruginosa propose that (i) planktonic cells become surface associated in a monolayer, (ii) surface-associated cells form microcolonies by clonal growth and/or aggregation, (iii) microcolonies transition to a mature biofilm comprised of exopolysaccharide-encased macrocolonies, and (iv) cells exit the mature biofilm and reenter the planktonic state. Here we report a new class of P. aeruginosa biofilm mutant that defines the transition from reversible to irreversible attachment and is thus required for monolayer formation. The transposon insertion carried by the sadB199 mutant was mapped to open reading frame PA5346 of P. aeruginosa PA14 and encodes a protein of unknown function. Complementation analysis and phage-mediated transduction demonstrated that the transposon insertion in PA5346 was the cause of the biofilm-defective phenotype. Examination of flow cell-grown biofilms showed that the sadB199 mutant could initiate surface attachment but failed to form microcolonies despite being proficient in both twitching and swimming motility. Closer examination of early attachment revealed an increased number of the sadB199 mutant cells arrested at reversible attachment, functionally defined as adherence via the cell pole. A positive correlation among biofilm formation, irreversible attachment, and SadB level was demonstrated, and furthermore, RpoN and FleR appear to negatively affect SadB levels. Fractionation studies showed that the SadB protein is localized to the cytoplasm, and with the use of GPS-linker scanning mutagenesis, the C-terminal portion of SadB was shown to be dispensable for function, whereas the two putative domains of unknown function and the linker region spanning these domains were required for function. We discuss the results presented here in the context of microbial development as it applies to biofilm formation.

scholarly journals Flagellar Stators Stimulate c-di-GMP Production by Pseudomonas aeruginosa

2019 ◽  
Vol 201 (18) ◽  
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 ◽  
Flagellar Motility ◽  
Swarming Motility ◽  
Surface Attachment ◽  
Content Type ◽  
Bidirectional Interactions ◽  
Gmp Production

ABSTRACT Flagellar 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 while c-di-GMP can influence stator localization, stators can in turn 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 under 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 to define the bidirectional interactions between c-di-GMP and the flagellar machinery. IMPORTANCE The ability of bacterial cells to control motility during early steps in biofilm formation is critical for the transition to a nonmotile, 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 the 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.

scholarly journals Cyclic Di-GMP-Mediated Repression of Swarming Motility by Pseudomonas aeruginosa PA14 Requires the MotAB Stator

2014 ◽  
Vol 197 (3) ◽  
pp. 420-430 ◽  
Author(s):  
S. L. Kuchma ◽  
N. J. Delalez ◽  
L. M. Filkins ◽  
E. A. Snavely ◽  
J. P. Armitage ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Point Mutations ◽  
Second Messenger ◽  
Swarming Motility ◽  
Content Type ◽  
In The Wild ◽  
Green Fluorescent

The second messenger cyclic diguanylate (c-di-GMP) plays a critical role in the regulation of motility. InPseudomonas aeruginosaPA14, c-di-GMP inversely controls biofilm formation and surface swarming motility, with high levels of this dinucleotide signal stimulating biofilm formation and repressing swarming.P. aeruginosaencodes two stator complexes, MotAB and MotCD, that participate in the function of its single polar flagellum. Here we show that the repression of swarming motility requires a functional MotAB stator complex. Mutating themotABgenes restores swarming motility to a strain with artificially elevated levels of c-di-GMP as well as stimulates swarming in the wild-type strain, while overexpression of MotA from a plasmid represses swarming motility. Using point mutations in MotA and the FliG rotor protein of the motor supports the conclusion that MotA-FliG interactions are critical for c-di-GMP-mediated swarming inhibition. Finally, we show that high c-di-GMP levels affect the localization of a green fluorescent protein (GFP)-MotD fusion, indicating a mechanism whereby this second messenger has an impact on MotCD function. We propose that when c-di-GMP level is high, the MotAB stator can displace MotCD from the motor, thereby affecting motor function. Our data suggest a newly identified means of c-di-GMP-mediated control of surface motility, perhaps conserved amongPseudomonas,Xanthomonas, and other organisms that encode two stator systems.

Bioactivity of Phenolic Compounds Extracted from Strawberry against Formation of Pseudomonas aeruginosa Biofilm

2019 ◽  
Vol 10 (01) ◽  
Author(s):  
Baydaa Hussein ◽  
Zainab A. Aldhaher ◽  
Shahrazad Najem Abdu-Allah ◽  
Adel Hamdan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phenolic Compounds ◽  
Biofilm Formation ◽  
Opportunistic Infections ◽  
Formation Rate ◽  
Hydrocarbon Chain ◽  
Health Concern ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenolic Contents

Background: Biofilm is a bacterial way of life prevalent in the world of microbes; in addition to that it is a source of alarm in the field of health concern. Pseudomonas aeruginosa is a pathogenic bacterium responsible for all opportunistic infections such as chronic and severe. Aim of this study: This paper aims to provide an overview of the promotion of isolates to produce a biofilm in vitro under special circumstances, to expose certain antibiotics to produce phenotypic evaluation of biofilm bacteria. Methods and Materials: Three diverse ways were used to inhibited biofilm formation of P.aeruginosa by effect of phenolic compounds extracts from strawberries. Isolates produced biofilm on agar MacConkey under certain circumstances. Results: The results showed that all isolates were resistant to antibiotics except sensitive to azithromycin (AZM, 15μg), and in this study was conducted on three ways to detect the biofilm produced, has been detected by the biofilm like Tissue culture plate (TCP), Tube method (TM), Congo Red Agar (CRA). These methods gave a clear result of these isolates under study. Active compounds were analyzed in both extracts by Gas Chromatography-mass Spectrometry which indicate High molecular weight compound with a long hydrocarbon chain. Conclusion: Phenolic compounds could behave as bioactive material and can be useful to be used in pharmaceutical synthesis. Phenolic contents which found in leaves and fruits extracts of strawberries shows antibacterial activity against all strains tested by the ability to reduce the production of biofilm formation rate.

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