Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Pyocyanin degradation by a tautomerizing demethylase inhibits Pseudomonas aeruginosa biofilms.

ABSTRACT: The opportunistic pathogen Pseudomonas aeruginosa produces colorful redox-active metabolites called phenazines, which underpin biofilm development, virulence, and clinical outcomes. Although phenazines exist in many forms, the best studied is pyocyanin. Here, we describe pyocyanin demethylase (PodA), a hitherto uncharacterized protein that oxidizes the pyocyanin methyl group to formaldehyde and reduces the pyrazine ring via an unusual tautomerizing demethylation reaction. Treatment with PodA disrupts P. aeruginosa biofilm formation similarly to DNase, suggesting interference with the pyocyanin-dependent release of extracellular DNA into the matrix. PodA-dependent pyocyanin demethylation also restricts established biofilm aggregate populations experiencing anoxic conditions. Together, these results show that modulating extracellular redox-active metabolites can influence the fitness of a biofilm-forming microorganism.

SUBMITTER: Costa KC

PROVIDER: S-EPMC5303695 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Pyocyanin degradation by a tautomerizing demethylase inhibits Pseudomonas aeruginosa biofilms.

Costa Kyle C KC Glasser Nathaniel R NR Conway Stuart J SJ Newman Dianne K DK

Science (New York, N.Y.) 20161208 6321

The opportunistic pathogen Pseudomonas aeruginosa produces colorful redox-active metabolites called phenazines, which underpin biofilm development, virulence, and clinical outcomes. Although phenazines exist in many forms, the best studied is pyocyanin. Here, we describe pyocyanin demethylase (PodA), a hitherto uncharacterized protein that oxidizes the pyocyanin methyl group to formaldehyde and reduces the pyrazine ring via an unusual tautomerizing demethylation reaction. Treatment with PodA dis ...[more]

PMID: 27940577

Similar Datasets

Computationally designed pyocyanin demethylase acts synergistically with tobramycin to kill recalcitrant <i>Pseudomonas aeruginosa</i> biofilms.

Project description:Pseudomonas aeruginosa is an opportunistic human pathogen that develops difficult-to-treat biofilms in immunocompromised individuals, cystic fibrosis patients, and in chronic wounds. P. aeruginosa has an arsenal of physiological attributes that enable it to evade standard antibiotic treatments, particularly in the context of biofilms where it grows slowly and becomes tolerant to many drugs. One of its survival strategies involves the production of the redox-active phenazine, pyocyanin, which promotes biofilm development. We previously identified an enzyme, PodA, that demethylated pyocyanin and disrupted P. aeruginosa biofilm development in vitro. Here, we asked if this protein could be used as a potential therapeutic for P. aeruginosa infections together with tobramycin, an antibiotic typically used in the clinic. A major roadblock to answering this question was the poor yield and stability of wild-type PodA purified from standard Escherichia coli overexpression systems. We hypothesized that the insufficient yields were due to poor packing within PodA's obligatory homotrimeric interfaces. We therefore applied the protein design algorithm, AffiLib, to optimize the symmetric core of this interface, resulting in a design that incorporated five mutations leading to a 20-fold increase in protein yield from heterologous expression and purification and a substantial increase in stability to environmental conditions. The addition of the designed PodA with tobramycin led to increased killing of P. aeruginosa cultures under oxic and hypoxic conditions in both the planktonic and biofilm states. This study highlights the potential for targeting extracellular metabolites to assist the control of P. aeruginosa biofilms that tolerate conventional antibiotic treatment.

| S-EPMC8000102 | biostudies-literature

Extracellular DNA Promotes Efficient Extracellular Electron Transfer by Pyocyanin in Pseudomonas aeruginosa Biofilms.

Project description:Redox cycling of extracellular electron shuttles can enable the metabolic activity of subpopulations within multicellular bacterial biofilms that lack direct access to electron acceptors or donors. How these shuttles catalyze extracellular electron transfer (EET) within biofilms without being lost to the environment has been a long-standing question. Here, we show that phenazines mediate efficient EET through interactions with extracellular DNA (eDNA) in Pseudomonas aeruginosa biofilms. Retention of pyocyanin (PYO) and phenazine carboxamide in the biofilm matrix is facilitated by eDNA binding. In vitro, different phenazines can exchange electrons in the presence or absence of DNA and can participate directly in redox reactions through DNA. In vivo, biofilm eDNA can also support rapid electron transfer between redox active intercalators. Together, these results establish that PYO:eDNA interactions support an efficient redox cycle with rapid EET that is faster than the rate of PYO loss from the biofilm.

| S-EPMC7457544 | biostudies-literature

Human targets of Pseudomonas aeruginosa pyocyanin.

Project description:Pseudomonas aeruginosa produces copious amounts of the redoxactive tricyclic compound pyocyanin that kills competing microbes and mammalian cells, especially during cystic fibrosis lung infection. Cross-phylum susceptibility to pyocyanin suggests the existence of evolutionarily conserved physiological targets. We screened a Saccharomyces cerevisiae deletion library to identify presumptive pyocyanin targets with the expectation that similar targets would be conserved in humans. Fifty S. cerevisiae targets were provisionally identified, of which 60% have orthologous human counterparts. These targets encompassed major cellular pathways involved in the cell cycle, electron transport and respiration, epidermal cell growth, protein sorting, vesicle transport, and the vacuolar ATPase. Using cultured human lung epithelial cells, we showed that pyocyanin-mediated reactive oxygen intermediates inactivate human vacuolar ATPase, supporting the validity of the yeast screen. We discuss how the inactivation of V-ATPase may negatively impact the lung function of cystic fibrosis patients.

| S-EPMC283589 | biostudies-literature

Raloxifene attenuates Pseudomonas aeruginosa pyocyanin production and virulence.

Project description:There has been growing interest in disrupting bacterial virulence mechanisms as a form of infectious disease control through the use of 'anti-infective' drugs. Pseudomonas aeruginosa is an opportunistic pathogen noted for its intrinsic antibiotic resistance that causes serious infections requiring new therapeutic options. In this study, an analysis of the P. aeruginosa PAO1 deduced proteome was performed to identify pathogen-associated proteins. A computational screening approach was then used to discover drug repurposing opportunities, i.e. identifying approved drugs that bind and potentially disrupt the pathogen-associated protein targets. The selective oestrogen receptor modulator raloxifene, a drug currently used in the prevention of osteoporosis and/or invasive breast cancer in post-menopausal women, was predicted from this screen to bind P. aeruginosa PhzB2. PhzB2 is involved in production of the blue pigment pyocyanin produced via the phenazine biosynthesis pathway. Pyocyanin is toxic to eukaryotic cells and has been shown to play a role in infection in a mouse model, making it an attractive target for anti-infective drug discovery. Raloxifene was found to strongly attenuate P. aeruginosa virulence in a Caenorhabditis elegans model of infection. Treatment of P. aeruginosa wild-type strains PAO1 and PA14 with raloxifene resulted in a dose-dependent reduction in pyocyanin production in vitro; pyocyanin production and virulence were also reduced for a phzB2 insertion mutant. These results suggest that raloxifene may be suitable for further development as a therapeutic for P. aeruginosa infection and that such already approved drugs may be computationally screened and potentially repurposed as novel anti-infective/anti-virulence agents.

| S-EPMC5511546 | biostudies-literature

Pyocyanin biosynthesis protects Pseudomonas aeruginosa from nonthermal plasma inactivation.

Project description:Pseudomonas aeruginosa is an important opportunistic human pathogen, which raises a worldwide concern for its increasing resistance. Nonthermal plasma, which is also called cold atmospheric plasma (CAP), is an alternative therapeutic approach for clinical infectious diseases. However, the bacterial factors that affect CAP treatment remain unclear. The sterilization effect of a portable CAP device on different P. aeruginosa strains was investigated in this study. Results revealed that CAP can directly or indirectly kill P. aeruginosa in a time-dependent manner. Scanning electron microscopy and transmission electron microscope showed negligible surface changes between CAP-treated and untreated P. aeruginosa cells. However, cell leakage occurred during the CAP process with increased bacterial lactate dehydrogenase release. More importantly, pigmentation of the P. aeruginosa culture was remarkably reduced after CAP treatment. Further mechanical exploration was performed by utilizing mutants with loss of functional genes involved in pyocyanin biosynthesis, including P. aeruginosa PAO1 strain-derived phzA1::Tn, phzA2::Tn, ΔphzA1/ΔphzA2, phzM::Tn and phzS::Tn, as well as corresponding gene deletion mutants based on clinical PA1 isolate. The results indicated that pyocyanin and its intermediate 5-methyl phenazine-1-carboxylic acid (5-Me-PCA) play important roles in P. aeruginosa resistance to CAP treatment. The unique enzymes, such as PhzM in the pyocyanin biosynthetic pathway, could be novel targets for the therapeutic strategy design to control the growing P. aeruginosa infections.

| S-EPMC9151332 | biostudies-literature

Pyocyanin Restricts Social Cheating in <i>Pseudomonas aeruginosa</i>.

Project description:Quorum sensing (QS) in Pseudomonas aeruginosa coordinates the expression of virulence factors, such as exoproteases and siderophores, that are public goods utilized by the whole population of bacteria, regardless of whether they invested or not in their production. These public goods can be used by QS defective mutants for growth, and since these mutants do not contribute to public goods production, they are considered social cheaters. Pyocyanin is a phenazine that is a toxic, QS-controlled metabolite produced by P. aeruginosa. It is a redox-active compound and promotes the generation of reactive oxygen species; it also possesses antibacterial properties and increases fitness in competition with other bacterial species. Since QS-deficient individuals are less able to tolerate oxidative stress, we hypothesized that the pyocyanin produced by the wild-type population could promote selection of functional QS systems in this bacterium. Here, we demonstrate, using competition experiments and mathematical models, that, indeed, pyocyanin increases the fitness of the cooperative QS-proficient individuals and restricts the appearance of social cheaters. In addition, we also show that pyocyanin is able to select QS in other bacteria such as Acinetobacter baumannii.

| S-EPMC6030374 | biostudies-literature

Pyocyanin production by Pseudomonas aeruginosa confers resistance to ionic silver.

Project description:Silver in its ionic form (Ag+), but not the bulk metal (Ag0), is toxic to microbial life forms and has been used for many years in the treatment of wound infections. The prevalence of bacterial resistance to silver is considered low due to the nonspecific nature of its toxicity. However, the recent increased use of silver as an antimicrobial agent for medical, consumer, and industrial products has raised concern that widespread silver resistance may emerge. Pseudomonas aeruginosa is a common pathogen that produces pyocyanin, a redox toxin and a reductant for molecular oxygen and ferric (Fe3+) ions. The objective of this study was to determine whether pyocyanin reduces Ag+ to Ag0, which may contribute to silver resistance due to lower bioavailability of the cation. Using surface plasmon resonance spectroscopy and scanning electron microscopy, pyocyanin was confirmed to be a reductant for Ag+, forming Ag0 nanoparticles and reducing the bioavailability of free Ag+ by >95% within minutes. Similarly, a pyocyanin-producing strain of P. aeruginosa (PA14) reduced Ag+ but not a pyocyanin-deficient (?phzM) strain of the bacterium. Challenge of each strain with Ag+ (as AgNO3) gave MICs of 20 and 5 ?g/ml for the PA14 and ?phzM strains, respectively. Removal of pyocyanin from the medium strain PA14 was grown in or its addition to the medium that ?phzM mutant was grown in gave MICs of 5 and 20 ?g/ml, respectively. Clinical isolates demonstrated similar pyocyanin-dependent resistance to Ag+. We conclude that pseudomonal silver resistance exists independently of previously recognized intracellular mechanisms and may be more prevalent than previously considered.

| S-EPMC4135871 | biostudies-other

Development of potent inhibitors of pyocyanin production in Pseudomonas aeruginosa.

Project description:The development of new approaches for the treatment of antimicrobial-resistant infections is an urgent public health priority. The Pseudomonas aeruginosa pathogen, in particular, is a leading source of infection in hospital settings, with few available treatment options. In the context of an effort to develop antivirulence strategies to combat bacterial infection, we identified a series of highly effective small molecules that inhibit the production of pyocyanin, a redox-active virulence factor produced by P. aeruginosa. Interestingly, these new antagonists appear to suppress P. aeruginosa virulence factor production through a pathway that is independent of LasR and RhlR.

| S-EPMC4332565 | biostudies-literature

Electroceutical Treatment of Pseudomonas aeruginosa Biofilms.

Project description:Electroceutical wound dressings, especially those involving current flow with silver based electrodes, show promise for treating biofilm infections. However, their mechanism of action is poorly understood. We have developed an in vitro agar based model using a bioluminescent strain of Pseudomonas aeruginosa to measure loss of activity and killing when direct current was applied. Silver electrodes were overlaid with agar and lawn biofilms grown for 24 h. A 6 V battery with 1 kΩ ballast resistor was used to treat the biofilms for 1 h or 24 h. Loss of bioluminescence and a 4-log reduction in viable cells was achieved over the anode. Scanning electron microscopy showed damaged cells and disrupted biofilm architecture. The antimicrobial activity continued to spread from the anode for at least 2 days, even after turning off the current. Based on possible electrochemical ractions of silver electrodes in chlorine containing medium; pH measurements of the medium post treatment; the time delay between initiation of treatment and observed bactericidal effects; and the presence of chlorotyrosine in the cell lysates, hypochlorous acid is hypothesized to be the chemical agent responsible for the observed (destruction/killing/eradication) of these biofilm forming bacteria. Similar killing was obtained with gels containing only bovine synovial fluid or human serum. These results suggest that our in vitro model could serve as a platform for fundamental studies to explore the effects of electrochemical treatment on biofilms, complementing clinical studies with electroceutical dressings.

| S-EPMC6375951 | biostudies-literature

Thermal mitigation of Pseudomonas aeruginosa biofilms.

Project description:Bacterial biofilms infect 2-4% of medical devices upon implantation, resulting in multiple surgeries and increased recovery time due to the very great increase in antibiotic resistance in the biofilm phenotype. This work investigates the feasibility of thermal mitigation of biofilms at physiologically accessible temperatures. Pseudomonas aeruginosa biofilms were cultured to high bacterial density (1.7 × 10(9) CFU cm(-2)) and subjected to thermal shocks ranging from 50°C to 80°C for durations of 1-30 min. The decrease in viable bacteria was closely correlated with an Arrhenius temperature dependence and Weibull-style time dependence, demonstrating up to six orders of magnitude reduction in bacterial load. The bacterial load for films with more conventional initial bacterial densities dropped below quantifiable levels, indicating thermal mitigation as a viable approach to biofilm control.

| S-EPMC4617618 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data