scholarly journals Global Analysis of the Zinc Homeostasis Network in Pseudomonas aeruginosa and Its Gene Expression Dynamics

2021 ◽  
Vol 12 ◽  
Author(s):  
Verena Ducret ◽  
Melina Abdou ◽  
Catarina Goncalves Milho ◽  
Sara Leoni ◽  
Oriane Martin--Pelaud ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Global Analysis ◽  
Opportunistic Pathogen ◽  
Zinc Homeostasis ◽  
Protein Levels ◽  
Its Gene ◽  
Zn Homeostasis ◽  
Gene Expression Dynamics ◽  
Nanostring Technology

Zinc is one of the most important trace elements for life and its deficiency, like its excess, can be fatal. In the bacterial opportunistic pathogen Pseudomonas aeruginosa, Zn homeostasis is not only required for survival, but also for virulence and antibiotic resistance. Thus, the bacterium possesses multiple Zn import/export/storage systems. In this work, we determine the expression dynamics of the entire P. aeruginosa Zn homeostasis network at both transcript and protein levels. Precisely, we followed the switch from a Zn-deficient environment, mimicking the initial immune strategy to counteract bacterial infections, to a Zn-rich environment, representing the phagocyte metal boost used to eliminate an engulfed pathogen. Thanks to the use of the NanoString technology, we timed the global silencing of Zn import systems and the orchestrated induction of Zn export systems. We show that the induction of Zn export systems is hierarchically organized as a function of their impact on Zn homeostasis. Moreover, we identify PA2807 as a novel Zn resistance component in P. aeruginosa and highlight new regulatory links among Zn-homeostasis systems. Altogether, this work unveils a sophisticated and adaptive homeostasis network, which complexity is key in determining a pathogen spread in the environment and during host-colonization.

scholarly journals Global analysis of the zinc homeostasis network in Pseudomonas aeruginosa and its gene expression dynamics

2021 ◽  
Author(s):  
Verena Ducret ◽  
Melina Abdou ◽  
Catarina Goncalves Milho ◽  
Sara Leoni ◽  
Oriane Martin--Pelaud ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Global Analysis ◽  
Opportunistic Pathogen ◽  
Zinc Homeostasis ◽  
Protein Levels ◽  
Its Gene ◽  
Zn Homeostasis ◽  
Gene Expression Dynamics ◽  
Nanostring Technology

Zinc is one of the most important trace elements for life and its deficiency, like its excess, can be fatal. In the bacterial opportunistic pathogen Pseudomonas aeruginosa, Zn homeostasis is not only required for survival, but also for virulence and antibiotic resistance. Thus, the bacterium possesses multiple Zn import/export/storage systems. In this work, we determine the expression dynamics of the entire P. aeruginosa Zn homeostasis network at both transcript and protein levels. Precisely, we followed the switch from a Zn-deficient environment, mimicking the initial immune strategy to bacterial infections, to a Zn-rich environment, representing the phagocyte metal boost used to eliminate an engulfed pathogen. Thanks to the use of the NanoString technology, we timed the global silencing of Zn import systems and the orchestrated induction of Zn export systems. We show that the induction of Zn export systems is hierarchically organized as a function of their impact on Zn homeostasis. Moreover, we identify PA2807 as a novel Zn resistance component in P. aeruginosa and highlight new regulatory links among Zn-homeostasis systems. Altogether, this work unveils a sophisticated and adaptative homeostasis network, which complexity is key in determining a pathogen spread in the environment and during host-colonization.

scholarly journals Energy-Optimized Pharmacophore Coupled Virtual Screening in the Discovery of Quorum Sensing Inhibitors of LasR Protein of Pseudomonas aeruginosa

2019 ◽  
Author(s):  
Zulkar Nain ◽  
Sifat Bin Sayed ◽  
Mohammad Minnatul Karim ◽  
Md. Ariful Islam ◽  
Utpal Kumar Adhikari
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virtual Screening ◽  
Quorum Sensing ◽  
Bacterial Infections ◽  
Opportunistic Pathogen ◽  
Vital Role ◽  
Energy Calculation ◽  
Quorum Sensing Inhibitors ◽  
Binding Energy Calculation ◽  
Standard Precision

Pseudomonas aeruginosa is an emerging opportunistic pathogen responsible for cystic fibrosis and nosocomial infections. In addition, empirical treatments are become inefficient due to their multiple-antibiotic resistance and extensive colonizing ability. Quorum sensing (QS) plays a vital role in the regulation of virulence factors in P. aeruginosa. Attenuation of virulence by QS inhibition could be an alternative and effective approach to control infections. Therefore, we sought to discover new QS inhibitors (QSIs) against LasR receptor in P. aeruginosa using chemoinformatics. Initially, a structure-based high-throughput virtual screening was performed using the LasR active site that identified 61404 relevant molecules. E-pharmacophore (ADAHH) screening of these molecules rendered 72 QSI candidates. In standard-precision docking, only 7 compounds were found as potential QSIs due to their higher binding affinity to LasR receptor (-7.53 to -10.32 kcal/mol compared to -7.43 kcal/mol of native ligands). The ADMET properties of these compounds were suitable to be QSIs. Later, extra-precision docking and binding energy calculation suggested ZINC19765885 and ZINC72387263 as the most promising QSIs. The dynamic simulation of the docked complexes showed good binding stability and molecular interactions. The current study suggested that these two compounds could be used in P. aeruginosa QS inhibition to combat bacterial infections.

scholarly journals Neutron crystallography reveals novel mechanisms used by Pseudomonas aeruginosa for host-cell binding

2021 ◽  
Author(s):  
Lukas Gajdos ◽  
Matthew P Blakeley ◽  
Michael Haertlein ◽  
V Trevor Forsyth ◽  
Juliette M Devos ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Calcium Ions ◽  
Bacterial Infections ◽  
Opportunistic Pathogen ◽  
Host Cells ◽  
Carbohydrate Binding ◽  
Hydrogen Atoms ◽  
High Affinity ◽  
Structural Details ◽  
Neutron Crystallography

The opportunistic pathogen Pseudomonas aeruginosa, a major cause of nosocomial infections, uses carbohydrate-binding proteins (lectins) as part of its binding to host cells. The fucose-binding lectin, LecB, displays a unique carbohydrate-binding site that incorporates two closely located calcium ions bridging between the ligand and protein, providing specificity and unusually high affinity. Here, we investigate the mechanisms involved in binding based on neutron crystallography studies of a fully deuterated LecB/fucose/calcium complex. The neutron structure, which includes the positions of all the hydrogen atoms, reveals that the high affinity of binding may be related to the occurrence of a low barrier hydrogen bond induced by the proximity of the two calcium ions, the presence of coordination rings between the sugar, calcium and LecB, and the dynamic behaviour of bridging water molecules at room temperature. These key structural details may assist in the design of anti-adhesive compounds to combat multi-resistance bacterial infections.

scholarly journals Role of RgsA in oxidative stress resistance in Pseudomonas aeruginosa

2020 ◽  
Author(s):  
Shuyi Hou ◽  
Jiaqing Zhang ◽  
Xiaobo Ma ◽  
Qiang Hong ◽  
Lili Fang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
Regulatory Function ◽  
Rna Molecules ◽  
Protein Mass ◽  
Protein Levels ◽  
Protein Mass Spectrometry ◽  
Small Regulatory Rnas

AbstractPseudomonas aeruginosa is an extremely common opportunistic pathogen in clinical practice. Patients with metabolic disorders, hematologic diseases, malignancies, who have undergone surgery or who have received certain treatments are susceptible to this bacterium. In addition, P. aeruginosa is a multidrug-resistant that tends to form biofilms and is refractory to treatment. Small regulatory RNAs are RNA molecules that are 40–500 nucleotides long, possess regulatory function, are ubiquitous in bacteria, and are also known as small RNA (sRNA). sRNAs play important regulatory roles in various vital life processes in diverse bacteria and their quantity and diversity of regulatory functions exceeds that of proteins. In this study, we showed that deletion of the sRNA RgsA decreases the growth rate and ability to resist different concentrations and durations of peroxide in P. aeruginosa. These decreases occur not only in the planktonic state, but also in the biofilm state. Finally, protein mass spectrometry was employed to understand changes in the entire protein spectrum. The results presented herein provide a description of the role of RgsA in the life activities of P. aeruginosa at the molecular, phenotypic, and protein levels.

scholarly journals Traditional Chinese Medicine Tanreqing Inhibits Quorum Sensing Systems in Pseudomonas aeruginosa

2020 ◽  
Vol 11 ◽  
Author(s):  
Weifeng Yang ◽  
Qing Wei ◽  
Qian Tong ◽  
Kaiyu Cui ◽  
Gaiying He ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Bacterial Infections ◽  
Cell Communication ◽  
Opportunistic Pathogen ◽  
Communication Process ◽  
Phenotypic Analysis

Pseudomonas aeruginosa is an opportunistic pathogen that can infect a wide variety of hosts including humans, plants, and animals. The production of virulence factors is the determinant of the infection paradigm and is under orchestrated regulation via cell-to-cell communication process called quorum sensing (QS). To disable QS circuits and prevent bacterial infections, a large battery of anti-QS agents, particularly from traditional Chinese medicine have been developed. Here, we used P. aeruginosa as a model microorganism to investigate the effect of traditional Chinese medicine Tanreqing (TRQ) formula on bacterial pathogenicity. Phenotypic analysis showed that TRQ treatment could completely inhibit the production of phenazine pyocyanin and moderately inhibit the production of virulence factors such as rhamnolipids, elastase, and alkaline protease. Further transcriptomic analyses revealed that TRQ treatment could significantly attenuate the expression of QS-regulated genes in P. aeruginosa and TRQ-treated P. aeruginosa regulon shared a large overlap with QS regulon. Component contribution to QS inhibition shed light on the indispensable role of all five components in TRQ formula. Further genetic analysis indicated that upstream regulators of QS systems, including two-component systems GacS/GacA and PprA/PprB, were both inhibited by TRQ treatment. Finally, our TRQ formula could efficiently protect Caenorhabditis elegans from killing by P. aeruginosa. Altogether, we have proved TRQ formula as an effective and specific agent to attenuate bacterial virulence and combat bacterial infections.

scholarly journals Minimum Inhibitory Concentration of Ciprofloxacin against Pseudomonas Aeruginosa in the Presence of the Efflux Inhibitor Phenylalanine-arginine Beta-naphthylamide

2018 ◽  
Vol 3 (4) ◽  
Author(s):  
Fatemeh Abbasi ◽  
Saber Yusefi ◽  
Shohreh Afshar Yavar
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Minimum Inhibitory Concentration ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Opportunistic Pathogen ◽  
Outpatient Clinics ◽  
Multi Drug Resistance ◽  
Efflux System ◽  
Concentration Test ◽  
Multiple Drugs

Introduction: Pseudomonas aeruginosa is a gram-negative, opportunistic pathogen causing infections in patients staying in the hospital and is resistant to multiple drugs. This study investigated the resistance to ciprofloxacin by the efflux system of Pseudomonas aeruginosa.Materials and Methods: For this purpose, the inhibitor of the efflux system phenylalanine-arginine beta-naphthylamide was used. In this study, 135 isolates of Pseudomonas aeruginosa were collected from the hospitalized patients of Imam Khomeini Hospital and outpatient clinics in Urmia during a ten-month period from June 2015 to March 2016. These isolates were re-identified by standard microbiological and biochemical methods. Finally, 51 isolates were selected for antibiotic susceptibility testing.Results: According to the antibiogram test, the Pseudomonas aeruginosa isolates exhibited highest resistance against ciprofloxacin (90.2%), tobramycin (88.2%), and gentamycin (86.3%) and the highest sensitivity towards colistin (76.4%), and imipenem (72.5%). The 51 isolates, which were selected for the minimum inhibitory concentration test, had multi-drug resistance regulators.Conclusion: The discovery and development of the efflux system inhibitors is an important strategy to deal with bacterial infections.

scholarly journals Genetic and transcriptomic characteristics of RhlR-dependent quorum sensing in cystic fibrosis isolates of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Kyle L Asfahl ◽  
Nicole E Smalley ◽  
Alexandria P Chang ◽  
Ajai A Dandekar
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Bacterial Infections ◽  
Opportunistic Pathogen ◽  
Homoserine Lactone ◽  
Signaling Mechanism ◽  
Genetic Characteristics ◽  
Genes Encoding ◽  
A Cell

In people with the genetic disease cystic fibrosis (CF), bacterial infections involving the opportunistic pathogen Pseudomonas aeruginosa are a significant cause of morbidity and mortality. P. aeruginosa uses a cell-cell signaling mechanism called quorum sensing (QS) to regulate many virulence functions. One type of QS consists of acyl-homoserine lactone (AHL) signals produced by LuxI-type signal synthases, which bind a cognate LuxR-type transcription factor. In laboratory strains and conditions, P. aeruginosa employs two AHL synthase/receptor pairs arranged in a hierarchy, with the LasI/R system controlling the RhlI/R system and many downstream virulence factors. However, P. aeruginosa isolates with inactivating mutations in lasR are frequently isolated from chronic CF infections. We and others have shown that these isolates frequently use RhlR as the primary QS regulator. RhlR is rarely mutated in CF and environmental settings. We were interested if there were reproducible genetic characteristics of these isolates and if there was a central group of genes regulated by RhlR in all isolates. We examined five isolates and found signatures of adaptation common to CF isolates. We did not identify a common genetic mechanism to explain the switch from Las- to Rhl-dominated QS. We describe a core RhlR regulon encompassing 20 genes encoding 7 products. These results suggest a key group of QS-regulated factors important for pathogenesis of chronic infection, and position RhlR as a target for anti-QS therapeutics. Our work underscores the need to sample a diversity of isolates to understanding QS beyond what has been described in laboratory strains.

scholarly journals A Cationic Porphyrin, ZnPor, Disassembles Pseudomonas aeruginosa Biofilm Matrix, Kills Cells Directly, and Enhances Antibiotic Activity of Tobramycin

Antibiotics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 875
Author(s):  
Neha Patel ◽  
Shawn Swavey ◽  
Jayne Robinson
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Opportunistic Pathogen ◽  
Uptake System ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Antibiotic Resistant ◽  
The Matrix ◽  
Life Threatening ◽  
Pre Treatment

One of the greatest threats to human health is the rise in antibiotic-resistant bacterial infections. Pseudomonas aeruginosa (PsA) is an “opportunistic” pathogen known to cause life-threatening infections in immunocompromised individuals and is the most common pathogen in adults with cystic fibrosis (CF). We report here a cationic zinc (II) porphyrin, ZnPor, that effectively kills planktonic and biofilm-associated cells of PsA. In standard tests against 16–18 h-old biofilms, concentrations as low as 16 µg/mL resulted in the extensive disruption and detachment of the matrix. The pre-treatment of biofilms for 30 min with ZnPor at minimum inhibitory concentration (MIC) levels (4 µg/mL) substantially enhanced the ability of tobramycin (Tobra) to kill biofilm-associated cells. We demonstrate the rapid uptake and accumulation of ZnPor in planktonic cells even in dedicated heme-uptake system mutants (ΔPhu, ΔHas, and the double mutant). Furthermore, uptake was unaffected by the ionophore carbonyl cyanide m-chlorophenyl hydrazine (CCCP). Cells pre-exposed to ZnPor took up the cell-impermeant dye SYTOXTM Green in a concentration-dependent manner. The accumulation of ZnPor did not result in cell lysis, nor did the cells develop resistance. Taken together, these properties make ZnPor a promising candidate for treating multi-drug-resistant infections, including persistent, antibiotic-resistant biofilms.

scholarly journals Food as a Source for Quorum Sensing Inhibitors: Iberin from Horseradish Revealed as a Quorum Sensing Inhibitor of Pseudomonas aeruginosa

2012 ◽  
Vol 78 (7) ◽  
pp. 2410-2421 ◽  
Author(s):  
Tim Holm Jakobsen ◽  
Steinn Kristinn Bragason ◽  
Richard Kerry Phipps ◽  
Louise Dahl Christensen ◽  
Maria van Gennip ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Bacterial Infections ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Array Detector ◽  
Content Type ◽  
Health Promoting ◽  
Microarray Studies

ABSTRACTFoods with health-promoting effects beyond nutritional values have been gaining increasing research focus in recent years, although not much has been published on this subject in relation to bacterial infections. With respect to treatment, a novel antimicrobial strategy, which is expected to transcend problems with selective pressures for antibiotic resistance, is to interrupt bacterial communication, also known as quorum sensing (QS), by means of signal antagonists, the so-called QS inhibitors (QSIs). Furthermore, QSI agents offer a potential solution to the deficiencies associated with use of traditional antibiotics to treat infections caused by bacterial biofilms and multidrug-resistant bacteria. Several QSIs of natural origin have been identified, and in this study, several common food products and plants were extracted and screened for QSI activity in an attempt to isolate and characterize previously unknown QSI compounds active against the common opportunistic pathogenPseudomonas aeruginosa. Several extracts displayed activity, but horseradish exhibited the highest activity. Chromatographic separation led to the isolation of a potent QSI compound that was identified by liquid chromatography-diode array detector-mass spectrometry (LC-DAD-MS) and nuclear magnetic resonance (NMR) spectroscopy as iberin—an isothiocyanate produced by many members of theBrassicaceaefamily. Real-time PCR (RT-PCR) and DNA microarray studies showed that iberin specifically blocks expression of QS-regulated genes inP. aeruginosa.

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