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Maybin JA, Thompson TP, Flynn PB, Skvortsov T, Hickok NJ, Freeman TA, Gilmore BF. Cold atmospheric pressure plasma-antibiotic synergy in Pseudomonas aeruginosa biofilms is mediated via oxidative stress response. Biofilm 2023; 5:100122. [PMID: 37214348 PMCID: PMC10196807 DOI: 10.1016/j.bioflm.2023.100122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/06/2023] [Accepted: 04/06/2023] [Indexed: 05/24/2023] Open
Abstract
Cold atmospheric-pressure plasma (CAP) has emerged as a potential alternative or adjuvant to conventional antibiotics for the treatment of bacterial infections, including those caused by antibiotic-resistant pathogens. The potential of sub-lethal CAP exposures to synergise conventional antimicrobials for the eradication of Pseudomonas aeruginosa biofilms is investigated in this study. The efficacy of antimicrobials following or in the absence of sub-lethal CAP pre-treatment in P. aeruginosa biofilms was assessed. CAP pre-treatment resulted in an increase in both planktonic and biofilm antimicrobial sensitivity for all three strains tested (PAO1, PA14, and PA10548), with both minimum inhibitory concentrations (MICs) and minimum biofilm eradication concentrations (MBECs) of individual antimicrobials, being significantly reduced following CAP pre-treatment of the biofilm (512-fold reduction with ciprofloxacin/gentamicin; and a 256-fold reduction with tobramycin). At all concentrations of antimicrobial used, the combination of sub-lethal CAP exposure and antimicrobials was effective at increasing time-to-peak metabolism, as measured by isothermal microcalorimetry, again indicating enhanced susceptibility. CAP is known to damage bacterial cell membranes and DNA by causing oxidative stress through the in situ generation of reactive oxygen and nitrogen species (RONS). While the exact mechanism is not clear, oxidative stress on outer membrane proteins is thought to damage/perturb cell membranes, confirmed by ATP and LDH leakage, allowing antimicrobials to penetrate the bacterial cell more effectively, thus increasing bacterial susceptibility. Transcriptomic analysis, reveals that cold-plasma mediated oxidative stress caused upregulation of P. aeruginosa superoxide dismutase, cbb3 oxidases, catalases, and peroxidases, and upregulation in denitrification genes, suggesting that P. aeruginosa uses these enzymes to degrade RONS and mitigate the effects of cold plasma mediated oxidative stress. CAP treatment also led to an increased production of the signalling molecule ppGpp in P. aeruginosa, indicative of a stringent response being established. Although we did not directly measure persister cell formation, this stringent response may potentially be associated with the formation of persister cells in biofilm cultures. The production of ppGpp and polyphosphate may be associated with protein synthesis inhibition and increase efflux pump activity, factors which can result in antimicrobial tolerance. The transcriptomic analysis also showed that by 6 h post-treatment, there was downregulation in ribosome modulation factor, which is involved in the formation of persister cells, suggesting that the cells had begun to resuscitate/recover. In addition, CAP treatment at 4 h post-exposure caused downregulation of the virulence factors pyoverdine and pyocyanin; by 6 h post-exposure, virulence factor production was increasing. Transcriptomic analysis provides valuable insights into the mechanisms by which P. aeruginosa biofilms exhibits enhanced susceptibility to antimicrobials. Overall, these findings suggest, for the first time, that short CAP sub-lethal pre-treatment can be an effective strategy for enhancing the susceptibility of P. aeruginosa biofilms to antimicrobials and provides important mechanistic insights into cold plasma-antimicrobial synergy. Transcriptomic analysis of the response to, and recovery from, sub-lethal cold plasma exposures in P. aeruginosa biofilms improves our current understanding of cold plasma biofilm interactions.
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Affiliation(s)
- Jordanne-Amee Maybin
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Thomas P Thompson
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Padrig B Flynn
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Timofey Skvortsov
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
| | - Noreen J Hickok
- Department of Orthopaedic Surgery Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Theresa A Freeman
- Department of Orthopaedic Surgery Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Brendan F Gilmore
- Biofilm Research Group, School of Pharmacy, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, 19 Chlorine Gardens, Belfast, BT9 5DL, UK
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M Shafik S, Abbas HA, Yousef N, Saleh MM. Crippling of Klebsiella pneumoniae virulence by metformin, N-acetylcysteine and secnidazole. BMC Microbiol 2023; 23:229. [PMID: 37608306 PMCID: PMC10464179 DOI: 10.1186/s12866-023-02969-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 08/04/2023] [Indexed: 08/24/2023] Open
Abstract
INTRODUCTION The emergence of multidrug-resistant Klebsiella pneumoniae in hospitals represents a serious threat to public health. Infections caused by Klebsiella pneumoniae are widespread in healthcare institutions, mainly pneumonia, bloodstream infections, and infections affecting neonates in intensive care units; so, it is necessary to combat this pathogen with new strategies. Targeting virulence factors necessary to induce host damage and disease is a new paradigm for antimicrobial therapy with several potential benefits that could lead to decreased resistance. BACKGROUND The influence of metformin, N-acetylcysteine, and secnidazole on Klebsiella pneumoniae virulence factors production was tested. The production of Klebsiella pneumoniae virulence factors such as biofilm formation, urease, proteases, hemolysins, and tolerance to oxidative stress was evaluated phenotypically using sub-inhibitory concentration (1/8 MIC) of metformin, N-acetylcysteine, and secnidazole. For more confirmation, qRT-PCR was used to assess the relative expression level of rmpA, wcaG, fimH-1, mrkD, ureA, and khe genes regulating virulence factors production. RESULTS Metformin, N-acetylcysteine, and secnidazole were all found to have a powerful inhibitory effect on the production of virulence factors phenotypically. Our results showed a significant reduction in the expression level of rmpA, wcaG, fimH-1, mrkD, ureA, and khe genes. Furthermore, the tested drugs were investigated in vivo to inform their ability to protect mice against Klebsiella pneumoniae pathogenesis. CONCLUSIONS Metformin, N-acetylcysteine, and secnidazole inhibited the virulence of Klebsiella pneumoniae. Besides combating resistant Klebsiella pneumoniae, the tested drugs could also serve as an adjuvant to traditional antibiotics.
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Affiliation(s)
- Shokri M Shafik
- Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig City, Egypt
| | - Hisham A Abbas
- Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig City, Egypt
| | - Nehal Yousef
- Microbiology and Immunology Department, Faculty of Pharmacy, Zagazig University, Zagazig City, Egypt
| | - Moustafa M Saleh
- Microbiology and Immunology Department, Faculty of Pharmacy, Port Said University, Port Said City, Egypt.
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Singh M, Penmatsa A, Nandi D. Functional Characterization of Salmonella Typhimurium Encoded YciF, a Domain of Unknown Function (DUF892) Family Protein, and Its Role in Protection during Bile and Oxidative Stress. J Bacteriol 2023; 205:e0005923. [PMID: 37367303 PMCID: PMC10367587 DOI: 10.1128/jb.00059-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
YciF (STM14_2092) is a member of the domain of unknown function (DUF892) family. It is an uncharacterized protein involved in stress responses in Salmonella Typhimurium. In this study, we investigated the significance of YciF and its DUF892 domain during bile and oxidative stress responses of S. Typhimurium. Purified wild-type YciF forms higher order oligomers, binds to iron, and displays ferroxidase activity. Studies on the site-specific mutants revealed that the ferroxidase activity of YciF is dependent on the two metal binding sites present within the DUF892 domain. Transcriptional analysis displayed that the ΔcspE strain, which has compromised expression of YciF, encounters iron toxicity due to dysregulation of iron homeostasis in the presence of bile. Utilizing this observation, we demonstrate that the bile mediated iron toxicity in ΔcspE causes lethality, primarily through the generation of reactive oxygen species (ROS). Expression of wild-type YciF, but not the three mutants of the DUF892 domain, in ΔcspE alleviate ROS in the presence of bile. Our results establish the role of YciF as a ferroxidase that can sequester excess iron in the cellular milieu to counter ROS-associated cell death. This is the first report of biochemical and functional characterization of a member of the DUF892 family. IMPORTANCE The DUF892 domain has a wide taxonomic distribution encompassing several bacterial pathogens. This domain belongs to the ferritin-like superfamily; however, it has not been biochemically and functionally characterized. This is the first report of characterization of a member of this family. In this study, we demonstrate that S. Typhimurium YciF is an iron binding protein with ferroxidase activity, which is dependent on the metal binding sites present within the DUF892 domain. YciF combats iron toxicity and oxidative damage caused due to exposure to bile. The functional characterization of YciF delineates the significance of the DUF892 domain in bacteria. In addition, our studies on S. Typhimurium bile stress response divulged the importance of comprehensive iron homeostasis and ROS in bacteria.
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Affiliation(s)
- Madhulika Singh
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Aravind Penmatsa
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Dipankar Nandi
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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Khayat MT, Abbas HA, Ibrahim TS, Elbaramawi SS, Khayyat AN, Alharbi M, Hegazy WAH, Yehia FAZA. Synergistic Benefits: Exploring the Anti-Virulence Effects of Metformin/Vildagliptin Antidiabetic Combination against Pseudomonas aeruginosa via Controlling Quorum Sensing Systems. Biomedicines 2023; 11:biomedicines11051442. [PMID: 37239113 DOI: 10.3390/biomedicines11051442] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/10/2023] [Accepted: 05/11/2023] [Indexed: 05/28/2023] Open
Abstract
The repurposing of drugs is one of the most competent strategies for discovering new antimicrobial agents. Vildagliptin is a dipeptidyl peptidase-4 inhibitor (DPI-4) that is used effectively in combination with metformin to control blood glucose levels in diabetic patients. This study was designed to evaluate the anti-virulence activities of this combination against one of the most clinically important pathogens, Pseudomonas aeruginosa. The current findings show a significant ability of the vildagliptin-metformin combination to diminish biofilm formation, bacterial motility, and the production of virulent extracellular enzymes and pyocyanin pigment. Furthermore, this drug combination significantly increased the susceptibility of P. aeruginosa to oxidative stress, indicating immunity enhancement in the eradication of bacterial cells. In compliance with the in vitro findings, the histopathological photomicrographs of mice showed a considerable protective effect of the metformin-vildagliptin combination against P. aeruginosa, revealing relief of inflammation due to P. aeruginosa-induced pathogenesis. P. aeruginosa mainly employs quorum sensing (QS) systems to control the production of its huge arsenal of virulence factors. The anti-virulence activities of the metformin-vildagliptin combination can be interrupted by the anti-QS activities of both metformin and vildagliptin, as both exhibited a considerable affinity to QS receptors. Additionally, the metformin-vildagliptin combination significantly downregulated the expression of the main three QS-encoding genes in P. aeruginosa. These findings show the significant anti-virulence activities of metformin-vildagliptin at very low concentrations (10, 1.25 mg/mL, respectively) compared to the concentrations (850, 50 mg/mL, respectively) used to control diabetes.
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Affiliation(s)
- Maan T Khayat
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Hisham A Abbas
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Tarek S Ibrahim
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Samar S Elbaramawi
- Medicinal Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Ahdab N Khayyat
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Majed Alharbi
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Wael A H Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
- Pharmacy Program, Department of Pharmaceutical Sciences, Oman College of Health Sciences, Muscat 113, Oman
| | - Fatma Al-Zahraa A Yehia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
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Izrael Živković L, Hüttmann N, Susevski V, Medić A, Beškoski V, Berezovski MV, Minić Z, Živković L, Karadžić I. A comprehensive proteomics analysis of the response of Pseudomonas aeruginosa to nanoceria cytotoxicity. Nanotoxicology 2023; 17:20-41. [PMID: 36861958 DOI: 10.1080/17435390.2023.2180451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
The increased commercial use and spread of nanoceria raises concerns about the risks associated with its effects on living organisms. Although Pseudomonas aeruginosa may be ubiquitous in nature, it is largely found in locations closely linked with human activity. P. aeruginosa san ai was used as a model organism for a deeper understanding of the interaction between biomolecules of the bacteria with this intriguing nanomaterial. A comprehensive proteomics approach along with analysis of altered respiration and production of targeted/specific secondary metabolites was conducted to study the response of P. aeruginosa san ai to nanoceria. Quantitative proteomics found that proteins associated with redox homeostasis, biosynthesis of amino acids, and lipid catabolism were upregulated. Proteins from outer cellular structures were downregulated, including transporters responsible for peptides, sugars, amino acids and polyamines, and the crucial TolB protein of the Tol-Pal system, required for the structural formation of the outer membrane layer. In accordance with the altered redox homeostasis proteins, an increased amount of pyocyanin, a key redox shuttle, and the upregulation of the siderophore, pyoverdine, responsible for iron homeostasis, were found. Production of extracellular molecules, e.g. pyocyanin, pyoverdine, exopolysaccharides, lipase, and alkaline protease, was significantly increased in P. aeruginosa san ai exposed to nanoceria. Overall, nanoceria at sublethal concentrations induces profound metabolic changes in P. aeruginosa san ai and provokes increased secretion of extracellular virulence factors, revealing the powerful influence this nanomaterial has on the vital functions of the microorganism.
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Affiliation(s)
| | - Nico Hüttmann
- John L. Holmes Mass Spectrometry Facility, University of Ottawa, Ottawa, Ontario, Canada
| | - Vanessa Susevski
- John L. Holmes Mass Spectrometry Facility, University of Ottawa, Ottawa, Ontario, Canada
| | - Ana Medić
- Department of Chemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Vladimir Beškoski
- Department of Biochemistry, Faculty of Chemistry, University of Belgrade, Belgrade, Serbia
| | - Maxim V Berezovski
- John L. Holmes Mass Spectrometry Facility, University of Ottawa, Ottawa, Ontario, Canada
| | - Zoran Minić
- John L. Holmes Mass Spectrometry Facility, University of Ottawa, Ottawa, Ontario, Canada
| | - Ljiljana Živković
- The Vinča Institute of Nuclear Sciences, University of Belgrade, Belgrade, Serbia
| | - Ivanka Karadžić
- Department of Chemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
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Monothiol Glutaredoxin Is Essential for Oxidative Stress Protection and Virulence in Pseudomonas aeruginosa. Appl Environ Microbiol 2023; 89:e0171422. [PMID: 36533942 PMCID: PMC9888271 DOI: 10.1128/aem.01714-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Glutaredoxins (Grxs), ubiquitous redox enzymes belonging to the thioredoxin family, catalyze the reduction of thiol-disulfide exchange reactions in a glutathione-dependent manner. A Pseudomonas aeruginosa ΔgrxD mutant exhibited hypersensitivity to oxidative stress-generating agents, such as paraquat (PQ) and cumene hydroperoxide (CHP). In vitro studies showed that P. aeruginosa GrxD acts as an electron donor for organic hydroperoxide resistance enzyme (Ohr) during CHP degradation. The ectopic expression of iron-sulfur cluster ([Fe-S]) carrier proteins, including ErpA, IscA, and NfuA, complements the function of GrxD in the ΔgrxD mutant under PQ toxicity. Constitutively high expression of iscR, nfuA, tpx, and fprB was observed in the ΔgrxD mutant. These results suggest that GrxD functions as a [Fe-S] cluster carrier protein involved in [Fe-S] cluster maturation. Moreover, the ΔgrxD mutant demonstrates attenuated virulence in a Drosophila melanogaster host model. Altogether, the data shed light on the physiological role of GrxD in oxidative stress protection and virulence of the human pathogen, P. aeruginosa. IMPORTANCE Glutaredoxins (Grxs) are ubiquitous disulfide reductase enzymes. Monothiol Grxs, containing a CXXS motif, play an essential role in iron homeostasis and maturation of [Fe-S] cluster proteins in various organisms. We now establish that the human pathogen Pseudomonas aeruginosa GrxD is crucial for bacterial virulence, maturation of [Fe-S] clusters and facilitation of Ohr enzyme activity. GrxD contains a conserved signature monothiol motif (C29GFS), in which C29 is essential for its function in an oxidative stress protection. Our findings reveal the physiological roles of GrxD in oxidative stress protection and virulence of P. aeruginosa.
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Saleh MM, Yousef N, Shafik SM, Abbas HA. Attenuating the virulence of the resistant superbug Staphylococcus aureus bacteria isolated from neonatal sepsis by ascorbic acid, dexamethasone, and sodium bicarbonate. BMC Microbiol 2022; 22:268. [PMID: 36348266 PMCID: PMC9644464 DOI: 10.1186/s12866-022-02684-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/29/2022] [Indexed: 11/11/2022] Open
Abstract
Background Infections affecting neonates caused by Staphylococcus aureus are widespread in healthcare facilities; hence, novel strategies are needed to fight this pathogen. In this study, we aimed to investigate the effectiveness of the FDA-approved medications ascorbic acid, dexamethasone, and sodium bicarbonate to reduce the virulence of the resistant Staphylococcus aureus bacteria that causes neonatal sepsis and seek out suitable alternatives to the problem of multi-drug resistance. Methods Tested drugs were assessed phenotypically and genotypically for their effects on virulence factors and virulence-encoding genes in Staphylococcus aureus. Furthermore, drugs were tested in vivo for their ability to reduce Staphylococcus aureus pathogenesis. Results Sub-inhibitory concentrations (1/8 MIC) of ascorbic acid, dexamethasone, and sodium bicarbonate reduced the production of Staphylococcus aureus virulence factors, including biofilm formation, staphyloxanthin, proteases, and hemolysin production, as well as resistance to oxidative stress. At the molecular level, qRT-PCR was used to assess the relative expression levels of crtM, sigB, sarA, agrA, hla, fnbA, and icaA genes regulating virulence factors production and showed a significant reduction in the relative expression levels of all the tested genes. Conclusions The current findings reveal that ascorbic acid, dexamethasone, and sodium bicarbonate have strong anti-virulence effects against Staphylococcus aureus. Thus, suggesting that they might be used as adjuvants to treat infections caused by Staphylococcus aureus in combination with conventional antimicrobials or as alternative therapies.
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Rodríguez-Esperón MC, Eastman G, Sandes L, Garabato F, Eastman I, Iriarte A, Fabiano E, Sotelo-Silveira JR, Platero R. Genomics and transcriptomics insights into luteolin effects on the beta-rhizobial strain Cupriavidus necator UYPR2.512. Environ Microbiol 2021; 24:240-264. [PMID: 34811861 DOI: 10.1111/1462-2920.15845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 11/04/2021] [Accepted: 11/08/2021] [Indexed: 11/28/2022]
Abstract
Cupriavidus necator UYPR2.512 is a rhizobial strain that belongs to the Beta-subclass of proteobacteria, able to establish successful symbiosis with Mimosoid legumes. The initial steps of rhizobium-legumes symbioses involve the reciprocal recognition by chemical signals, being luteolin one of the molecules involved. However, there is a lack of information on the effect of luteolin in beta-rhizobia. In this work, we used long-read sequencing to complete the genome of UYPR2.512 providing evidence for the existence of four closed circular replicons. We used an RNA-Seq approach to analyse the response of UYPR2.512 to luteolin. One hundred and forty-five genes were differentially expressed, with similar numbers of downregulated and upregulated genes. Most repressed genes were mapped to the main chromosome, while the upregulated genes were overrepresented among pCne512e, containing the symbiotic genes. Induced genes included the nod operon and genes implicated in exopolysaccharides and flagellar biosynthesis. We identified many genes involved in iron, copper and other heavy metals metabolism. Among repressed genes, we identified genes involved in basal carbon and nitrogen metabolism. Our results suggest that in response to luteolin, C. necator strain UYPR2.512 reshapes its metabolism in order to be prepared for the forthcoming symbiotic interaction.
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Affiliation(s)
- M C Rodríguez-Esperón
- Laboratorio de Microbiología Ambiental, Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - G Eastman
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - L Sandes
- Laboratorio de Microbiología Ambiental, Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - F Garabato
- Laboratorio de Microbiología Ambiental, Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - I Eastman
- Laboratorio de Microbiología Ambiental, Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - A Iriarte
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Instituto de Higiene, Montevideo, Uruguay
| | - E Fabiano
- Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - J R Sotelo-Silveira
- Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - R Platero
- Laboratorio de Microbiología Ambiental, Departamento de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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The Human Innate Immune Protein Calprotectin Elicits a Multimetal Starvation Response in Pseudomonas aeruginosa. Microbiol Spectr 2021; 9:e0051921. [PMID: 34549997 PMCID: PMC8557868 DOI: 10.1128/spectrum.00519-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
To combat infections, the mammalian host limits availability of essential transition metals such as iron (Fe), zinc (Zn), and manganese (Mn) in a strategy termed "nutritional immunity." The innate immune protein calprotectin (CP) contributes to nutritional immunity by sequestering these metals to exert antimicrobial activity against a broad range of microbial pathogens. One such pathogen is Pseudomonas aeruginosa, which causes opportunistic infections in vulnerable populations, including individuals with cystic fibrosis. CP was previously shown to withhold Fe(II) and Zn(II) from P. aeruginosa and induce Fe and Zn starvation responses in this pathogen. In this work, we performed quantitative, label-free proteomics to further elucidate how CP impacts metal homeostasis pathways in P. aeruginosa. We report that CP induces an incomplete Fe starvation response, as many Fe-containing proteins that are repressed by Fe limitation are not affected by CP treatment. The Zn starvation response elicited by CP seems to be more complete than the Fe starvation response and includes increases in Zn transporters and Zn-independent proteins. CP also induces the expression of membrane-modifying proteins, and metal depletion studies indicate this response results from the sequestration of multiple metals. Moreover, the increased expression of membrane-modifying enzymes upon CP treatment correlates with increased tolerance to polymyxin B. Thus, the response of P. aeruginosa to CP treatment includes both single- and multimetal starvation responses and includes many factors related to virulence potential, broadening our understanding of this pathogen's interaction with the host. IMPORTANCE Transition metal nutrients are critical for growth and infection by all pathogens, and the innate immune system withholds these metals from pathogens to limit their growth in a strategy termed "nutritional immunity." While multimetal depletion by the host is appreciated, the majority of studies have focused on individual metals. Here, we use the innate immune protein calprotectin (CP), which complexes with several metals, including iron (Fe), zinc (Zn), and manganese (Mn), and the opportunistic pathogen Pseudomonas aeruginosa to investigate multimetal starvation. Using an unbiased label-free proteomics approach, we demonstrate that multimetal withholding by CP induces a regulatory response that is not merely additive of individual metal starvation responses, including the induction of lipid A modification proteins.
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Decreased biofilm formation in Proteus mirabilis after short-term exposure to a simulated microgravity environment. Braz J Microbiol 2021; 52:2021-2030. [PMID: 34558030 PMCID: PMC8578233 DOI: 10.1007/s42770-021-00588-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 08/03/2021] [Indexed: 11/30/2022] Open
Abstract
Background Microbes threaten human health in space exploration. Studies have shown that Proteus mirabilis has been found in human space habitats. In addition, the biological characteristics of P. mirabilis in space have been studied unconditionally. The simulated microgravity environment provides a platform for understanding the changes in the biological characteristics of P. mirabilis. Objective This study intends to explore the effect of simulated microgravity on P. mirabilis, the formation of P. mirabilis biofilm, and its related mechanism. Methods The strange deformable rods were cultured continuously for 14 days under microgravity simulated in high-aspect rotating vessels (HARVs). The morphology, growth rate, metabolism, and biofilm formation of the strain were measured, and the phenotypic changes of P. mirabilis were evaluated. Transcriptome sequencing was used to detect differentially expressed genes under simulated microgravity and compared with phenotype. Results The growth rate, metabolic ability, and biofilm forming ability of P. mirabilis were lower than those of normal gravity culture under the condition of simulated microgravity. Further analysis showed that the decrease of growth rate, metabolic ability, and biofilm forming ability may be caused by the downregulation of related genes (pstS, sodB, and fumC). Conclusion The simulated microgravity condition enables us to explore the potential relationship between bacterial phenotype and molecular biology, thus opening up a suitable and constructive method for medical fields that have not been explored before. It provides a certain strategy for the treatment of P. mirabilis infectious diseases in space environment by exploring the microgravity of P. mirabilis. Supplementary Information The online version contains supplementary material available at 10.1007/s42770-021-00588-y.
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Oxidative Stress Response in Pseudomonas aeruginosa. Pathogens 2021; 10:pathogens10091187. [PMID: 34578219 PMCID: PMC8466533 DOI: 10.3390/pathogens10091187] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative environmental and human opportunistic pathogen highly adapted to many different environmental conditions. It can cause a wide range of serious infections, including wounds, lungs, the urinary tract, and systemic infections. The high versatility and pathogenicity of this bacterium is attributed to its genomic complexity, the expression of several virulence factors, and its intrinsic resistance to various antimicrobials. However, to thrive and establish infection, P. aeruginosa must overcome several barriers. One of these barriers is the presence of oxidizing agents (e.g., hydrogen peroxide, superoxide, and hypochlorous acid) produced by the host immune system or that are commonly used as disinfectants in a variety of different environments including hospitals. These agents damage several cellular molecules and can cause cell death. Therefore, bacteria adapt to these harsh conditions by altering gene expression and eliciting several stress responses to survive under oxidative stress. Here, we used PubMed to evaluate the current knowledge on the oxidative stress responses adopted by P. aeruginosa. We will describe the genes that are often differently expressed under oxidative stress conditions, the pathways and proteins employed to sense and respond to oxidative stress, and how these changes in gene expression influence pathogenicity and the virulence of P. aeruginosa. Understanding these responses and changes in gene expression is critical to controlling bacterial pathogenicity and developing new therapeutic agents.
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Could the analgesic drugs, paracetamol and indomethacin, function as quorum sensing inhibitors? Microb Pathog 2021; 158:105097. [PMID: 34284088 DOI: 10.1016/j.micpath.2021.105097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/05/2020] [Accepted: 07/15/2021] [Indexed: 11/22/2022]
Abstract
The current failure of antimicrobials in treating life-threatening diseases, the high rate of multidrug resistant pathogens and the slow progress in the development of new antibiotics directed scientists to develop antivirulence drugs that targets quorum sensing (QS). In many microbes, QS acts as a communication system which control pathogenicity of microbes. Analgesics can be beneficial in controlling virulence traits of microbes and hence they may augment the efficacy of antimicrobials. In this study, two analgesics were screened for the inhibition of QS in Chromobacterium violaceum CV026 and their effects on virulence production in Pseudomonas aeruginosa PAO1 strain and clinical isolates of Acinetobacter baumannii were evaluated. The traits investigated were biofilm formation, pyocyanin and rhamnolipid production, twitching, swarming or surface associated motilities, production of protease, phospholipase and gelatinase enzymes and sensitivity to oxidative stress. Relative expression of abaI gene was calculated by performing qRT-PCR. Docking analysis of paracetamol as QSI (quorum sensing inhibitor) of AbaI and AbaR proteins was performed. Paracetamol inhibited QS in CV026, but indomethacin devoids anti-QS activity. Paracetamol inhibited virulence factors of PAO1. It strongly inhibited biofilm formation, and swarming by 66.4% and 57.1%, respectively. While, it moderately to slightly inhibited rhamnolipid, pyocyanin, gelatinase, resistance to oxidative stress, protease and twitching motility by 33.3%, 33.1% 17.5%, 9.1%, 8.7% and 7.7%, respectively. For A. baumannii, paracetamol strongly inhibited biofilm by 39.7-93% and phospholipase enzyme by 8.7-100%, reduced twitching and surface motility by 6.7-82.5% and 7.7-29.4%, respectively, And slightly reduced sensitivity to oxidative stress by 3.3-36.4%. Paracetamol at sub-MIC suppressed the expression of abaI gene by 32% in A. baumannii. Docking studies suggested that paracetamol can bind to AbaR and AbaI proteins and bind more to AbaR, hence it may act by inhibiting AHL signal reception. As a conclusion, paracetamol, beside its analgesic activity, has anti-QS activity and could be used in the eradication of P. aeruginosa and A. baumannii infections in combination with antibiotics.
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13
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Khayyat AN, Hegazy WAH, Shaldam MA, Mosbah R, Almalki AJ, Ibrahim TS, Khayat MT, Khafagy ES, Soliman WE, Abbas HA. Xylitol Inhibits Growth and Blocks Virulence in Serratia marcescens. Microorganisms 2021; 9:microorganisms9051083. [PMID: 34070043 PMCID: PMC8158113 DOI: 10.3390/microorganisms9051083] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/09/2021] [Accepted: 05/12/2021] [Indexed: 12/15/2022] Open
Abstract
Serratia marcescens is an opportunistic nosocomial pathogen and causes wound and burn infections. It shows high resistance to antibiotics and its pathogenicity is mediated by an arsenal of virulence factors. Another therapeutic option to such infections is targeting quorum sensing (QS), which controls the expression of different S. marcescens virulence factors. Prevention of QS can deprive S. marcescens from its bacterial virulence without applying stress on the bacterial growth and facilitates the eradication of the bacteria by immunity. The objective of the current study is to explore the antimicrobial and antivirulence activities of xylitol against S. marcescens. Xylitol could inhibit the growth of S. marcescens. Sub-inhibitory concentrations of xylitol could inhibit biofilm formation, reduce prodigiosin production, and completely block protease activity. Moreover, xylitol decreased swimming motility, swarming motility and increased the sensitivity to hydrogen peroxide. The expression of rsmA, pigP, flhC, flhD fimA, fimC, shlA bsmB, and rssB genes that regulate virulence factor production was significantly downregulated by xylitol. In silico study showed that xylitol could bind with the SmaR receptor by hydrophobic interaction and hydrogen bonding, and interfere with the binding of the natural ligand with SmaR receptor. An in vivo mice survival test confirmed the ability of xylitol to protect mice against the virulence of S. marcescens. In conclusion, xylitol is a growth and virulence inhibitor in S. marcescens and can be employed for the treatment of S. marcescens wound and burn infections.
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Affiliation(s)
- Ahdab N. Khayyat
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (A.N.K.); (A.J.A.); (T.S.I.); (M.T.K.)
| | - Wael A. H. Hegazy
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;
- Correspondence: ; Tel.: +20-1101188800
| | - Moataz A. Shaldam
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt;
| | - Rasha Mosbah
- Infection control Unit, Zagazig University Hospitals, Zagazig University, Zagazig 44519, Egypt;
- Faculty of Oral and Dental medicine, Ahram Canadian University, Giza Governorate 12573, Egypt
| | - Ahmad J. Almalki
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (A.N.K.); (A.J.A.); (T.S.I.); (M.T.K.)
| | - Tarek S. Ibrahim
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (A.N.K.); (A.J.A.); (T.S.I.); (M.T.K.)
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt
| | - Maan T. Khayat
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Jeddah 21589, Saudi Arabia; (A.N.K.); (A.J.A.); (T.S.I.); (M.T.K.)
| | - El-Sayed Khafagy
- Department of Pharmaceutics, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-kharj 11942, Saudi Arabia;
- Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Suez Canal University, Ismailia 41552, Egypt
| | - Wafaa E. Soliman
- Department of Biomedical science, Faculty of Clinical Pharmacy, King Faisal University, Alhofuf, Al-Ahsa 36362, Saudi Arabia;
- Department of Microbiology and Biotechnology, Faculty of Pharmacy, Delta University for Science and Technology, Mansoura 11152, Egypt
| | - Hisham A. Abbas
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig 44519, Egypt;
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14
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Cianciulli Sesso A, Lilić B, Amman F, Wolfinger MT, Sonnleitner E, Bläsi U. Gene Expression Profiling of Pseudomonas aeruginosa Upon Exposure to Colistin and Tobramycin. Front Microbiol 2021; 12:626715. [PMID: 33995291 PMCID: PMC8120321 DOI: 10.3389/fmicb.2021.626715] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/31/2021] [Indexed: 11/22/2022] Open
Abstract
Pseudomonas aeruginosa (Pae) is notorious for its high-level resistance toward clinically used antibiotics. In fact, Pae has rendered most antimicrobials ineffective, leaving polymyxins and aminoglycosides as last resort antibiotics. Although several resistance mechanisms of Pae are known toward these drugs, a profounder knowledge of hitherto unidentified factors and pathways appears crucial to develop novel strategies to increase their efficacy. Here, we have performed for the first time transcriptome analyses and ribosome profiling in parallel with strain PA14 grown in synthetic cystic fibrosis medium upon exposure to polymyxin E (colistin) and tobramycin. This approach did not only confirm known mechanisms involved in colistin and tobramycin susceptibility but revealed also as yet unknown functions/pathways. Colistin treatment resulted primarily in an anti-oxidative stress response and in the de-regulation of the MexT and AlgU regulons, whereas exposure to tobramycin led predominantly to a rewiring of the expression of multiple amino acid catabolic genes, lower tricarboxylic acid (TCA) cycle genes, type II and VI secretion system genes and genes involved in bacterial motility and attachment, which could potentially lead to a decrease in drug uptake. Moreover, we report that the adverse effects of tobramycin on translation are countered with enhanced expression of genes involved in stalled ribosome rescue, tRNA methylation and type II toxin-antitoxin (TA) systems.
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Affiliation(s)
- Anastasia Cianciulli Sesso
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Branislav Lilić
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Fabian Amman
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Michael T Wolfinger
- Institute for Theoretical Chemistry, University of Vienna, Vienna, Austria.,Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
| | - Elisabeth Sonnleitner
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Udo Bläsi
- Max Perutz Labs, Vienna Biocenter (VBC), Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
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15
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Dulyayangkul P, Satapoomin N, Avison MB, Charoenlap N, Vattanaviboon P, Mongkolsuk S. Over-Expression of Hypochlorite Inducible Major Facilitator Superfamily (MFS) Pumps Reduces Antimicrobial Drug Susceptibility by Increasing the Production of MexXY Mediated by ArmZ in Pseudomonas aeruginosa. Front Microbiol 2021; 11:592153. [PMID: 33510718 PMCID: PMC7835679 DOI: 10.3389/fmicb.2020.592153] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022] Open
Abstract
Pseudomonas aeruginosa, a well-known cause of nosocomial infection, is frequently antibiotic resistant and this complicates treatment. Links between oxidative stress responses inducing antibiotic resistance through over-production of RND-type efflux pumps have been reported in P. aeruginosa, but this has not previously been associated with MFS-type efflux pumps. Two MFS efflux pumps encoded by mfs1 and mfs2 were selected for study because they were found to be sodium hypochlorite (NaOCl) inducible. Antibiotic susceptibility testing was used to define the importance of these MFS pumps in antibiotic resistance and proteomics was used to characterize the resistance mechanisms involved. The results revealed that mfs1 is NaOCl inducible whereas mfs2 is NaOCl, N-Ethylmaleimide and t-butyl hydroperoxide inducible. Deletion of mfs1 or mfs2 did not affect antibiotic or paraquat susceptibility. However, over-production of Mfs1 and Mfs2 reduced susceptibility to aminoglycosides, quinolones, and paraquat. Proteomics, gene expression analysis and targeted mutagenesis showed that over-production of the MexXY RND-type efflux pump in a manner dependent upon armZ, but not amgRS, is the cause of reduced antibiotic susceptibility upon over-production of Mfs1 and Mfs2. mexXY operon expression analysis in strains carrying various lengths of mfs1 and mfs2 revealed that at least three transmembrane domains are necessary for mexXY over-expression and decreased antibiotic susceptibility. Over-expression of the MFS-type efflux pump gene tetA(C) did not give the same effect. Changes in paraquat susceptibility were independent of mexXY and armZ suggesting that it is a substrate of Mfs1 and Mfs2. Altogether, this is the first evidence of cascade effects where the over-production of an MFS pump causes over-production of an RND pump, in this case MexXY via increased armZ expression.
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Affiliation(s)
- Punyawee Dulyayangkul
- Program in Applied Biological Sciences: Environmental Health, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Naphat Satapoomin
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Matthew B Avison
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Nisanart Charoenlap
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Paiboon Vattanaviboon
- Program in Applied Biological Sciences: Environmental Health, Chulabhorn Graduate Institute, Chulabhorn Royal Academy, Bangkok, Thailand.,Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | - Skorn Mongkolsuk
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
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16
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Wu Y, Deng G, Jiang K, Wang H, Song Z, Han H. Photothermally triggered nitric oxide nanogenerator targeting type IV pili for precise therapy of bacterial infections. Biomaterials 2020; 268:120588. [PMID: 33307370 DOI: 10.1016/j.biomaterials.2020.120588] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/27/2020] [Accepted: 11/27/2020] [Indexed: 12/24/2022]
Abstract
Nitric oxide (NO) is an important biological messenger involved in the treatment of bacterial infections, but its controlled and targeted release in bacterial infections remains a major challenge. Herein, an intelligent NO nanogenerator triggered by near-infrared (NIR) light is constructed for targeted treatment of P. aeruginosa bacterial infection. Since maleimide can recognize and attach to the pilus of T4P of P. aeruginosa, we adopt this strategy to achieve the accurate release of therapeutic drugs at the infection site, i.e., after maleimide targets Gram-negative bacteria, the SNP@MOF@Au-Mal nanogenerator will release NO and generate ROS in situ from the inorganic photosensitizer gold nanoparticles under NIR irradiation to achieve synergistic antibacterial effect. In vivo experiments proved that the bacterial burden on the wound was reduced by 97.7%. Additionally, the nanogenerator was shown to promote the secretion of growth factors, which play a key role in regulating inflammation and inducing angiogenesis. This strategy has the advantage of generating a high concentration of NO in situ to promote the transfer of more NO and its derivatives (N2O3, ONOO-) to bacteria, thereby significantly improving the antibacterial effect. The multifunctional antibacterial platform has been demonstrated as a good carrier for gas therapy because of its simple and efficient gas release performance, indicating its great potential for the treatment of drug-resistant bacterial infections.
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Affiliation(s)
- Yang Wu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Guiyun Deng
- State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kai Jiang
- State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huajuan Wang
- State Key Laboratory of Agricultural Microbiology, College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhiyong Song
- State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Heyou Han
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China; State Key Laboratory of Agricultural Microbiology, College of Science, Huazhong Agricultural University, Wuhan, 430070, China; State Key Laboratory of Agricultural Microbiology, College of Food Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China.
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17
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Martins D, McKay GA, English AM, Nguyen D. Sublethal Paraquat Confers Multidrug Tolerance in Pseudomonas aeruginosa by Inducing Superoxide Dismutase Activity and Lowering Envelope Permeability. Front Microbiol 2020; 11:576708. [PMID: 33101252 PMCID: PMC7546422 DOI: 10.3389/fmicb.2020.576708] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/31/2020] [Indexed: 12/17/2022] Open
Abstract
Stressors and environmental cues shape the physiological state of bacteria, and thus how they subsequently respond to antibiotic toxicity. To understand how superoxide stress can modulate survival to bactericidal antibiotics, we examined the effect of intracellular superoxide generators, paraquat and menadione, on stationary-phase antibiotic tolerance of the opportunistic pathogen, Pseudomonas aeruginosa. We tested how pre-challenge with sublethal paraquat and menadione alters the tolerance to ofloxacin and meropenem in wild-type P. aeruginosa and mutants lacking superoxide dismutase (SOD) activity (sodAB), the paraquat responsive regulator soxR, (p)ppGpp signaling (relA spoT mutant), or the alternative sigma factor rpoS. We confirmed that loss of SOD activity impairs ofloxacin and meropenem tolerance in stationary phase cells, and found that sublethal superoxide generators induce drug tolerance by stimulating SOD activity. This response is rapid, requires de novo protein synthesis, and is RpoS-dependent but does not require (p)ppGpp signaling nor SoxR. We further showed that pre-challenge with sublethal paraquat induces a SOD-dependent reduction in cell-envelope permeability and ofloxacin penetration. Our results highlight a novel mechanism of hormetic protection by superoxide generators, which may have important implications for stress-induced antibiotic tolerance in P. aeruginosa cells.
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Affiliation(s)
- Dorival Martins
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada
| | - Geoffrey A McKay
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Ann M English
- Department of Chemistry and Biochemistry, Concordia University, Montreal, QC, Canada
| | - Dao Nguyen
- Meakins-Christie Laboratories, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, QC, Canada.,Department of Medicine, McGill University, Montreal, QC, Canada
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18
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Sotolon is a natural virulence mitigating agent in Serratia marcescens. Arch Microbiol 2020; 203:533-541. [PMID: 32970221 DOI: 10.1007/s00203-020-02039-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/25/2020] [Accepted: 09/12/2020] [Indexed: 12/12/2022]
Abstract
Serratia marcescens is an emerging opportunistic bacterium that can cause healthcare-associated infections. The high rate of multidrug resistance and the ability to produce a set of virulence factors, by which it can produce infectious diseases makes it urgent to find an alternative approach to the treatment of such infections. Disarming of virulence by targeting of quorum sensing (QS) as the regulating mechanism of virulence is a promising approach that has no effect on bacterial growth that is considered a key factor in emergence of resistance. This study was designed to investigate the ability of sub-inhibitory concentrations (sub-MICs) of sotolon to attenuate virulence of a clinical isolate of S. marcescens. Sotolon at 25 and 50 μg/ml inhibited 35.2 and 47.5% of biofilm formation, respectively. The inhibition of swimming motility were 41.4 and 69.3%, while that of swarming motility were 77.6 and 86.8% at 25 and 50 µg/ml, respectively. Moreover, sotolon reduced prodigiosin production by 76.6 and 87.6% at concentrations of 25 and 50 µg/ml, respectively. Protease activity was reduced by 25 µg/ml of sotolon by 54.8% and was completely blocked at 50 µg/ml. The relative expression of genes regulating virulence factors decreased by 40% for fimA, 29% for fimC, 59% for flhC, 57% for flhD, 39% for bsmB, 37% for rssB, 49% for rsmA, 54% for pigP, and 62% for shlA gene in the presence of 50 µg/ml sotolon. In conclusion, sotolon is an anti-virulence agent that could be used for the treatment of S.marcescens hospital-acquired infections.
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19
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Repurposing Anti-diabetic Drugs to Cripple Quorum Sensing in Pseudomonas aeruginosa. Microorganisms 2020; 8:microorganisms8091285. [PMID: 32842696 PMCID: PMC7569791 DOI: 10.3390/microorganisms8091285] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa is a significant human pathogen, it possesses almost all of the known antimicrobial resistance mechanisms. Quorum sensing (QS) is an intercellular communication system that orchestrates bacterial virulence and its targeting is an effective approach to diminish its pathogenesis. Repurposing of drugs is an advantageous strategy, in this study we aimed to repurpose the anti-diabetic drugs sitagliptin, metformin and vildagliptin as anti-QS in P. aeruginosa. The effects of sub-inhibitory concentrations of the tested drugs on the expression of QS-encoding genes and QS-regulated virulence factors were assessed. The protective activity of tested drugs on P. aeruginosa pathogenesis was evaluated in vivo on mice. In silico analysis was performed to evaluate the interference capabilities of the tested drugs on QS-receptors. Although the three drugs reduced the expression of QS-encoding genes, only sitagliptin inhibited the P. aeruginosa virulence in vitro and protected mice from it. In contrast, metformin showed significant in vitro anti-QS activities but failed to protect mice from P. aeruginosa. Vildagliptin did not show any in vitro or in vivo efficacy. Sitagliptin is a promising anti-QS agent because of its chemical nature that hindered QS-receptors. Moreover, it gives an insight to consider their similar chemical structures as anti-QS agents or even design new chemically similar anti-QS pharmacophores.
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20
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Henríquez T, Stein NV, Jung H. Resistance to Bipyridyls Mediated by the TtgABC Efflux System in Pseudomonas putida KT2440. Front Microbiol 2020; 11:1974. [PMID: 32973714 PMCID: PMC7461776 DOI: 10.3389/fmicb.2020.01974] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 07/27/2020] [Indexed: 01/26/2023] Open
Abstract
Resistance-nodulation-division (RND) transporters are involved in antibiotic resistance and have a broad substrate specificity. However, the physiological significance of these efflux pumps is not fully understood. Here, we have investigated the role of the RND system TtgABC in resistance to metal ion chelators in the soil bacterium Pseudomonas putida KT2440. We observed that the combined action of an RND inhibitor and the chelator 2,2'-bipyridyl inhibited bacterial growth. In addition, the deletion of ttgB made the strain susceptible to 2,2'-bipyridyl and natural bipyridyl derivatives such as caerulomycin A, indicating that TtgABC is required for detoxification of compounds of the bipyridyl family. Searching for the basis of growth inhibition by bipyridyls, we found reduced adenosine triphosphate (ATP) levels in the ttgB mutant compared to the wild type. Furthermore, the expression of genes related to iron acquisition and the synthesis of the siderophore pyoverdine were reduced in the mutant compared to the wild type. Investigating the possibility that 2,2'-bipyridyl in the ttgB mutant mediates iron accumulation in cells (which would cause the upregulation of genes involved in oxidative stress via the Fenton reaction), we measured the expression of genes coding for proteins involved in intracellular iron storage and the response to oxidative stress. However, none of the genes was significantly upregulated. In a further search for a possible link between 2,2'-bipyridyl and the observed phenotypes, we considered the possibility that the ion chelator limits the intracellular availability of metabolically important metal ions. In this context, we found that the addition of copper restores the growth of the ttgB mutant and the production of pyoverdine, suggesting a relationship between copper availability and iron acquisition. Taken together, the results suggest that detoxification of metal chelating compounds of the bipyridyl family produced by other bacteria or higher ordered organisms is one of the native functions of the RND efflux pump TtgABC. Without the efflux pump, these compounds may interfere with cell ion homeostasis with adverse effects on cell metabolism, including siderophore production. Finally, our results suggest that TtgABC is involved in resistance to bile salts and deoxycholate.
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Affiliation(s)
- Tania Henríquez
- Mikrobiologie, Biozentrum, Ludwig-Maximilians-Universität München, Munich, Germany
| | | | - Heinrich Jung
- Mikrobiologie, Biozentrum, Ludwig-Maximilians-Universität München, Munich, Germany
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21
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Luo J, Li X, Zhang J, Feng A, Xia M, Zhou M. Global regulator engineering enhances bioelectricity generation in Pseudomonas aeruginosa-inoculated MFCs. Biosens Bioelectron 2020; 163:112269. [PMID: 32568691 DOI: 10.1016/j.bios.2020.112269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 04/21/2020] [Accepted: 04/30/2020] [Indexed: 01/24/2023]
Abstract
The electricigens with high-electroactivity is essential for resolving the low electricity power output (EPT) of microbial fuel cells (MFCs). However, the manipulation by single functional genes shows limitation because electroactivity is a complex phenotype controlled by multiple genes. Herein, global regulator engineering (GRE) was developed to optimize the electroactivity of an isolated strain (Pseudomonas aeruginosa P3-A-11) using an exogenous global regulator IrrE (ionizing radiation resistance E linkage group) as an object. The GRE was implemented through in vitro random mutagenesis by error-prone PCR and in vivo high-through screening comprised of cultures color assay, PYO measurement and MFCs operation. Four mutants with higher electroactivity were obtained, among which, the mutant 11/M2-59 not only displayed the maximal power density, but also exhibited stronger salt tolerance, consequently showing good performance of MFCs in the presence of salt. Apart from the reduced internal resistance, the increase in phenazines amounts primarily contributed to EPT improvement, which was realized by enhancing the core biosynthesis pathway and affecting other pathways (such as central metabolism pathway, quorum sensing system, regulatory network). Notably, IrrE exerted its positive effect on electroactivity even without native regulators (such as PmpR and RpoS). In addition, the significant fluctuations in expression levels of stress-responsive genes mediated by GRE were closely associated with the enhanced salt tolerance. This work demonstrated that GRE was an effective approach for simultaneously optimizing multiple phenotypes (such as electroactivity and stress tolerance), and thus would provide more opportunities to create high-efficiency electricigens and further promoted the practical application of MFCs.
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Affiliation(s)
- Jianmei Luo
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China.
| | - Xiao Li
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - Jingmei Zhang
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - An Feng
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - Menglei Xia
- Key Laboratory of Industrial Fermentation Microbiology (Tianjin University of Science &Technology), Ministry of Education, Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, PR China
| | - Minghua Zhou
- Key Laboratory of Pollution Process and Environmental Criteria, Ministry of Education, Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300350, PR China.
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22
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Seleem NM, Abd El Latif HK, Shaldam MA, El-Ganiny A. Drugs with new lease of life as quorum sensing inhibitors: for combating MDR Acinetobacter baumannii infections. Eur J Clin Microbiol Infect Dis 2020; 39:1687-1702. [PMID: 32328851 PMCID: PMC7180647 DOI: 10.1007/s10096-020-03882-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/27/2020] [Indexed: 12/21/2022]
Abstract
The emergence of multidrug-resistant (MDR) strains is a major health problem worldwide. There is an urgent need for novel strategies to combat bacterial infections caused by MDR strains like Pseudomonas aeruginosa and Acinetobacter baumannii. Quorum sensing (QS) is a critical communication system in bacterial community controlling survival and virulence. The awareness of the importance of QS in bacterial infections has stimulated research to identify QS inhibitors (QSIs) to defeat microbes. In this study, four FDA-approved drugs (besides azithromycin as positive QSI) were tested for potential QS inhibition against clinical A. baumannii isolates and P. aeruginosa (PAO1) standard strain. The inhibitory effect of these drugs on virulence factors of both microbes has been investigated. The studied virulence factors include biofilm formation, twitching and swarming motilities, proteolytic enzyme production, and resistance to oxidative stress. The four tested drugs (erythromycin, levamisole, chloroquine, and propranolol) inhibited QS in Chromobacterium violaceum by 84, 72, 55.1, and 37.3%, respectively. They also significantly inhibited virulence factors in both PAO1 and A. baumannii at sub-inhibitory concentrations. These findings were confirmed by qRT-PCR and mice mortality test, where tested drugs highly repressed the expression of abaI gene and showed significantly improved mice survival rates. In addition, molecular docking studies against AbaI and AbaR proteins of QS system in A. baumannii revealed the potential inhibition of QS by tested drugs. Beside their known activities, the tested drugs could be given new life as QSIs to combat A. baumannii nosocomial infections (alone or in combination with antimicrobials).
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Affiliation(s)
- Noura M Seleem
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Hemat K Abd El Latif
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Moataz A Shaldam
- Department of Medicinal Chemistry, Faculty of Pharmacy, Kafr-elsheikh University, Kafr El Sheikh, 33516, Egypt
| | - Amira El-Ganiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
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Cavinato L, Genise E, Luly FR, Di Domenico EG, Del Porto P, Ascenzioni F. Escaping the Phagocytic Oxidative Burst: The Role of SODB in the Survival of Pseudomonas aeruginosa Within Macrophages. Front Microbiol 2020; 11:326. [PMID: 32210934 PMCID: PMC7077434 DOI: 10.3389/fmicb.2020.00326] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/14/2020] [Indexed: 12/25/2022] Open
Abstract
Reactive oxygen species (ROS) are small oxygen-derived molecules that are used to control infections by phagocytic cells. In macrophages, the oxidative burst produced by the NOX2 NADPH-oxidase is essential to eradicate engulfed pathogens by both oxidative and non-oxidative killing. Indeed, while the superoxide anion (O2-) produced by NOX2, and the other ROS derived from its transformation, can directly target pathogens, ROS also contribute to activation of non-oxidative microbicidal effectors. The response of pathogens to the phagocytic oxidative burst includes the expression of different enzymes that target ROS to reduce their toxicity. Superoxide dismutases (SODs) are the primary scavengers of O2-, which is transformed into H2O2. In the Gram-negative Salmonella typhimurium, periplasmic SODCI has a major role in bacterial resistance to NOX-mediated oxidative stress. In Pseudomonas aeruginosa, the two periplasmic SODs, SODB, and SODM, appear to contribute to bacterial virulence in small-animal models. Furthermore, NOX2 oxidative stress is essential to restrict P. aeruginosa survival in macrophages early after infection. Here, we focused on the role of P. aeruginosa SODs in the counteracting of the lethal effects of the macrophage oxidative burst. Through this study of the survival of sod mutants in macrophages and the measurement of ROS in infected macrophages, we have identified a dual, antagonistic, role for SODB in P. aeruginosa survival. Indeed, the survival of the sodB mutants, but not of the sodM mutants, was greater than that of the wild-type (WT) bacteria early after infection, and sodB-infected macrophages showed higher levels of O2- and lower levels of H2O2. This suggests that SODB contributes to the production of lethal doses of H2O2 within the phagosome. However, later on following infection, the sodB mutants survived less that the WT bacteria, which highlights the pro-survival role of SODB. We have explained this defensive role through an investigation of the activation of autophagy, which was greater in the sodB-infected macrophages.
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Affiliation(s)
- Luca Cavinato
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Elena Genise
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Francesco R Luly
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Enea G Di Domenico
- Microbiology and Virology, San Gallicano Dermatologic Institute, IRCCS, Rome, Italy
| | - Paola Del Porto
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
| | - Fiorentina Ascenzioni
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Rome, Italy
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Tribelli PM, Pezzoni M, Brito MG, Montesinos NV, Costa CS, López NI. Response to lethal UVA radiation in the Antarctic bacterium Pseudomonas extremaustralis: polyhydroxybutyrate and cold adaptation as protective factors. Extremophiles 2019; 24:265-275. [DOI: 10.1007/s00792-019-01152-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 12/03/2019] [Indexed: 12/14/2022]
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Effects of phenotypic variations on the microbial hydroxylation of fatty acids by Pseudomonas sp. NRRL B-2994. J Biosci Bioeng 2019; 129:41-46. [PMID: 31375401 DOI: 10.1016/j.jbiosc.2019.06.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 06/01/2019] [Accepted: 06/15/2019] [Indexed: 11/23/2022]
Abstract
Hydroxy fatty acids (HFAs) are highly valued industrial materials. Pseudomonas sp. NRRL B-2994 was used for stereospecific microbial biotransformation to hydroxylate unsaturated fatty acids (UFAs). As Pseudomonas sp. was continuously subcultured, the hydroxylation capability (both conversion rate and productivity) decreased. A morphology change was observed from large to small colonies. To produce stereospecific 10-hydroxy-12(Z)-octadecenoic acid from plant oils by using Pseudomonas sp. NRRL B-2994, the effect of phenotypic variations related to microbial hydroxylation of UFAs was confirmed. The conversion rate and the total productivity of creating HFAs from UFAs by microbial hydroxylation were highly dependent upon colony phenotype variations of Pseudomonas sp. NRRL B-2994. The morphological change was responsible for a lower rate of hydroxylation. The small colony variants showed increased hydrophobicity of the cell surface resulting in cell aggregation in liquid culture and lower hydroxylation due to limited exposure of substrates, UFAs. Small colony variants could be reverted to typical large colony variants. An economically feasible process was established for microbial hydroxylation using large colony variants with 50% HFA conversion rate and 10-15 g/L of productivity.
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Chen Y, Wu F, Pang H, Tang J, Cai S, Jian J. Superoxide dismutase B (sodB), an important virulence factor of Vibrio alginolyticus, contributes to antioxidative stress and its potential application for live attenuated vaccine. FISH & SHELLFISH IMMUNOLOGY 2019; 89:354-360. [PMID: 30959182 DOI: 10.1016/j.fsi.2019.03.061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/18/2019] [Accepted: 03/26/2019] [Indexed: 06/09/2023]
Abstract
Vibrio alginolyticus is an opportunistic and halophilic Gram-negative pathogen in limiting the development of aquatic industry and affecting human health. SODs are oxidative enzymes that play a critical role in oxidative defense. In this study, an in-frame deleted mutant strain (ΔsodB) was constructed by allelic exchange mutagenesis to investigate physiological role of sodB in pathogenicity of V. alginolyticus. The results exhibited that ΔsodB showed no differences in growth compared with wild-type strain HY9901 (WT), but led to increasing in biofilm formation, ECPase activity and sensitivity to hydrogen peroxide, decreasing in swarming motility, adherence to CIK cells, SOD activity and virulence. In addition, ΔsodB induced a high antibody titer and provided a valid protection with a relative percent survival value of 86.5% without inducing clinical symptoms after challenging with WT. These results suggest that sodB is important for normal physiological function, oxidation resistance and virulence in V. alginolyticus, and ΔsodB may be considered as an effective live attenuated vaccine against V. alginolyticus.
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Affiliation(s)
- Yanyan Chen
- Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, China
| | - Fenglei Wu
- Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, China
| | - Huanying Pang
- Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, China
| | - Jufen Tang
- Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, China
| | - Shuanghu Cai
- Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, China.
| | - Jichang Jian
- Fisheries College of Guangdong Ocean University, Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Zhanjiang, China.
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Sazykin I, Makarenko M, Khmelevtsova L, Seliverstova E, Rakin A, Sazykina M. Cyclohexane, naphthalene, and diesel fuel increase oxidative stress, CYP153, sodA, and recA gene expression in Rhodococcus erythropolis. Microbiologyopen 2019; 8:e00855. [PMID: 31119875 PMCID: PMC6816061 DOI: 10.1002/mbo3.855] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 04/13/2019] [Accepted: 04/16/2019] [Indexed: 12/27/2022] Open
Abstract
In this study, we compared the expression of CYP153, sodA, sodC, and recA genes and ROS generation in hydrocarbon-degrading Rhodococcus erythropolis in the presence of cyclohexane, naphthalene, and diesel fuel. The expression of cytochrome P450, sodA (encoding Fe/Mn superoxide dismutase), recA, and superoxide anion radical generation rate increased after the addition of all studied hydrocarbons. The peak of CYP153, sodA, and recA gene expression was registered in the presence of naphthalene. The same substrate upregulated the Cu/Zn superoxide dismutase gene, sodC. Cyclohexane generated the highest level of superoxide anion radical production. Hydrogen peroxide accumulated in the medium enriched with diesel fuel. Taken together, hydrocarbon biotransformation leads to oxidative stress and upregulation of antioxidant enzymes and CYP153 genes, and increases DNA reparation levels in R. erythropolis cells.
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Affiliation(s)
- Ivan Sazykin
- Southern Federal University, Rostov-on-Don, Russian Federation
| | | | | | | | - Alexander Rakin
- Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Jena, Germany
| | - Marina Sazykina
- Southern Federal University, Rostov-on-Don, Russian Federation
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Jair HW, Lu HF, Huang YW, Pan SY, Lin IL, Huang HH, Yang TC. Roles of the Two-MnSOD System of Stenotrophomonas maltophilia in the Alleviation of Superoxide Stress. Int J Mol Sci 2019; 20:ijms20071770. [PMID: 30974814 PMCID: PMC6479884 DOI: 10.3390/ijms20071770] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 03/28/2019] [Accepted: 04/09/2019] [Indexed: 01/04/2023] Open
Abstract
Manganese-dependent superoxide dismutase (MnSOD, SodA) and iron-dependent SOD (FeSOD, SodB) are critical cytosolic enzymes for alleviating superoxide stress. Distinct from the singular sodA gene in most bacteria, Stenotrophomonas maltophilia harbors two sodA genes, sodA1 and sodA2. The roles of SodA1, SodA2, and SodB of S. maltophilia in alleviating superoxide stress were investigated. The expression of sod genes was determined by promoter–xylE transcriptional fusion assay and qRT–PCR. SodA2 and sodB expressions were proportional to the bacterial logarithmic growth, but unaffected by menadione (MD), iron, or manganese challenges. SodA1 was intrinsically unexpressed and inducibly expressed by MD. Complementary expression of sodA1 was observed when sodA2 was inactivated. The individual or combined sod deletion mutants were constructed using the gene replacement strategy. The functions of SODs were assessed by evaluating cell viabilities of different sod mutants in MD, low iron-stressed, and/or low manganese-stressed conditions. Inactivation of SodA1 or SodA2 alone did not affect bacterial viability; however, simultaneously inactivating sodA1 and sodA2 significantly compromised bacterial viability in both aerobic growth and stressed conditions. SodA1 can either rescue or support SodA2 when SodA2 is defective or insufficiently potent. The presence of two MnSODs gives S. maltophilia an advantage against superoxide stress.
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Affiliation(s)
- Herng-Woei Jair
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei 11220; Taiwan.
| | - Hsu-Feng Lu
- Department of Clinical Pathology, Cheng Hsin General Hospital, Taipei 11220; Taiwan.
- Department of Restaurant, Hotel and Institutional Management, 24205, Fu-Jen Catholic University, New Taipei City 24205, Taiwan.
| | - Yi-Wei Huang
- Department of Biotechnology and Laboratory Science in Medicine, 11221, National Yang-Ming University, Taipei 11221, Taiwan.
| | - Sz-Yun Pan
- Department of Biotechnology and Laboratory Science in Medicine, 11221, National Yang-Ming University, Taipei 11221, Taiwan.
| | - I-Ling Lin
- Department of Biotechnology and Laboratory Science in Medicine, 11221, National Yang-Ming University, Taipei 11221, Taiwan.
| | - Hsin-Hui Huang
- Department of Biotechnology and Laboratory Science in Medicine, 11221, National Yang-Ming University, Taipei 11221, Taiwan.
| | - Tsuey-Ching Yang
- Department of Biotechnology and Laboratory Science in Medicine, 11221, National Yang-Ming University, Taipei 11221, Taiwan.
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29
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Abbas HA, Elsherbini AM, Shaldam MA. Glyceryl trinitrate blocks staphyloxanthin and biofilm formation in Staphylococcus aureus. Afr Health Sci 2019; 19:1376-1384. [PMID: 31148964 PMCID: PMC6531949 DOI: 10.4314/ahs.v19i1.10] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Staphylococcus aureus is an important nosocomial bacterium that is responsible for a number of infections that may be fatal. The treatment of such infections is limited by emergence of antibiotic resistance. Targeting virulence of Staphylococcus aureus may provide an alternative option to antibiotic that may bypass the emergence of resistant strains due to lack of stress on viability. Objectives Investigation of the ability of glyceryl trinitrate (GTN) to inhibit staphyloxanthin, biofilm and tolerance to oxidative stress. Methods The disk sensitivity method was used to detect the methicillin resistance of Staphylococcus aureus. The effect of sub-inhibitory concentration of GTN on biofilm formation, staphyloxanthin production and tolerance to oxidative stress was evaluated. Molecular docking study was used to investigate the ability of GTN to bind to dehydrosqualene synthase enzyme. Results GTN showed a significant inhibition of biofilm, staphyloxanthin and tolerance to oxidative stress. In the molecular docking study, it was found that GTN could bind to dehydrosqualene synthase enzyme by hydrogen bonding, electrostatic interaction and pi-cation interaction. Conclusion The present study revealed the ability of GTN to serve as a potential anti-virulence candidate for attenuation of S. aureus pathogenicity.
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Superoxide dismutase activity confers (p)ppGpp-mediated antibiotic tolerance to stationary-phase Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2018; 115:9797-9802. [PMID: 30201715 PMCID: PMC6166797 DOI: 10.1073/pnas.1804525115] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Metabolically quiescent bacteria represent a large proportion of those in natural and host environments, and they are often refractory to antibiotic treatment. Such drug tolerance is also observed in the laboratory during stationary phase, when bacteria face stress and starvation-induced growth arrest. Tolerance requires (p)ppGpp signaling, which mediates the stress and starvation stringent response (SR), but the downstream effectors that confer tolerance are unclear. We previously demonstrated that the SR is linked to increased antioxidant defenses in Pseudomonas aeruginosa We now demonstrate that superoxide dismutase (SOD) activity is a key factor in SR-mediated multidrug tolerance in stationary-phase P. aeruginosa Inactivation of the SR leads to loss of SOD activity and decreased multidrug tolerance during stationary phase. Genetic or chemical complementation of SOD activity of the ΔrelA spoT mutant (ΔSR) is sufficient to restore antibiotic tolerance to WT levels. Remarkably, we observe high membrane permeability and increased drug internalization upon ablation of SOD activity. Combined, our results highlight an unprecedented mode of SR-mediated multidrug tolerance in stationary-phase P. aeruginosa and suggest that inhibition of SOD activity may potentiate current antibiotics.
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Enhancement of bioelectricity generation via heterologous expression of IrrE in Pseudomonas aeruginosa-inoculated MFCs. Biosens Bioelectron 2018; 117:23-31. [PMID: 29879584 DOI: 10.1016/j.bios.2018.05.052] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 02/28/2018] [Accepted: 05/28/2018] [Indexed: 01/31/2023]
Abstract
Low electricity power output (EPT) is still the main bottleneck limited the industrial application of microbial fuel cells (MFCs). Herein, EPT enhancement by introducing an exogenous global regulator IrrE derived from Deinococcus radiodurans into electrochemically active bacteria (EAB) was explored using Pseudomonas aeruginosa PAO1 as a model strain, achieving a power density 71% higher than that of the control strain. Moreover, IrrE-expressing strain exhibited a remarkable increase in the total amount of electron shuttles (majorly phenazines compounds) and a little decrease in internal resistance, which should underlie the enhancement in extracellular electron transfer (EET) efficiency and EPT. Strikingly, IrrE significantly affected substrate utilization profiling, improved cell growth characterization and cell tolerance to various stresses. Further quantitative RT-PCR analysis revealed that IrrE led to many differentially expressed genes, which were responsible for phenazines core biosynthesis, biofilm formation, QS systems, transcriptional regulation, glucose metabolism and general stress response. The results substantiated that targeting cellular regulatory network by the introduction of exogenous global regulators could be a facile and promising approach for the enhancement of bioelectricity generation and cell multiple phenotypes, and thus would be of great potential application in the practical MFCs.
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32
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Si M, Feng Y, Chen K, Kang Y, Chen C, Wang Y, Shen X. Functional comparison of methionine sulphoxide reductase A and B in Corynebacterium glutamicum. J GEN APPL MICROBIOL 2017; 63:280-286. [PMID: 28904252 DOI: 10.2323/jgam.2017.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Methionine sulphoxide reductases (Msr) are able to reduce methionine sulfoxide to methionine and protect bacteria against reactive oxygen species (ROS). Many organisms express both methionine sulphoxide reductase A (MsrA), specific for methionine-S-sulfoxide and methionine sulphoxide reductase B (MsrB), active against methionine-R-sulfoxide. Corynebacterium glutamicum expresses MsrA, the function of which has been well defined; however, the function of MsrB has not been studied. Whether MsrB and MsrA play an equally important role in the antioxidant process is also poorly understood. In this study, we identified MsrB encoded by ncgl1823 in C. glutamicum, investigated its function and made a comparison with MsrA. The msrB gene showed a slight effect on utilizing methionine sulfoxide (MetO) as the sole Met source; however, the survival rates showed no sensitivity to oxidants. MsrB showed catalytic activity using thioredoxin/thioredoxin reductase (Trx/TrxR) reducing system as electron donors, but independent from the mycoredoxin 1/mycothione reductase/mycothiol (Mrx1/Mtr/MSH) system. Therefore, MsrB plays a limited role in resisting oxidative stress and it could reduce MetO to Met by the Trx/TrxR reducing system, which is useful for expanding the understanding of the functions of Msr in this important industrial microbe.
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Affiliation(s)
- Meiru Si
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University.,College of Life Sciences, Qufu Normal University
| | - Yanyan Feng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Keqi Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Yiwen Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Can Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University.,College of Life Science and Agronomy, Zhoukou Normal University
| | - Yao Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
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Abbas HA, Elsherbini AM, Shaldam MA. Repurposing metformin as a quorum sensing inhibitor in Pseudomonas aeruginosa. Afr Health Sci 2017; 17:808-819. [PMID: 29085409 PMCID: PMC5656202 DOI: 10.4314/ahs.v17i3.24] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Background Quorum sensing is a mechanism of intercellular communication that controls the production of virulence factors in Pseudomonas aeruginosa. Inhibition of quorum sensing can disarm the virulence factors without exerting stress on bacterial growth that leads to emergence of antibiotic resistance. Objectives Finding a new quorum sensing inhibitor and determining its inhibitory activities against virulence factors of Pseudomonas aeruginosa PAO1 strain. Methods Quorum sensing was evaluated by estimation of violacein production by Chromobacterium violaceum CV026. Molecular docking was used to investigate the possible binding of metformin to LasR and rhlR receptors. The inhibition of pyocyanin, hemolysin, protease, elastase in addition to swimming and twitching motilities, biofilm formation and resistance to oxidative stress by metformin was also assessed. Results Metformin significantly reduced the production of violacein pigment. Significant inhibition of pyocyanin, hemolysin, protease and elastase was achieved. Metformin markedly decreased biofilm formation, swimming and twitching motilities and increased the sensitivity to oxidative stress. In the molecular docking study, metformin could bind to LasR by hydrogen bonding and electrostatic interaction and to rhlR by hydrogen bonding only. Conclusion Metformin can act as a quorum sensing inhibitor and virulence inhibiting agent that may be useful in the treatment of Pseudomonas aeruginosa infection.
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34
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Schönherr-Hellec S, Klein G, Delannoy J, Ferraris L, Friedel I, Rozé JC, Butel MJ, Aires J. Comparative phenotypic analysis of "Clostridium neonatale" and Clostridium butyricum isolates from neonates. Anaerobe 2017; 48:76-82. [PMID: 28739338 DOI: 10.1016/j.anaerobe.2017.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/19/2017] [Accepted: 07/20/2017] [Indexed: 12/30/2022]
Abstract
"Clostridium neonatale" was recently described as a new species within the Cluster I of the Clostridium genus sensu stricto. In this study, we characterized "C. neonatale" isolates (n = 42) and compared their phenotypic properties with those of Clostridium butyricum (n = 26), a close related species. Strains isolated from fecal samples of healthy neonates were tested for different phenotypic characteristics. Compared to C. butyricum, "C. neonatale" showed a significant higher surface hydrophobicity (p = 0.0047), exopolysaccharide production (p = 0.0069), aero-tolerance (p = 0.0222) and viability at 30 °C (p = 0.0006). A lower swimming ability (p = 0.0146) and tolerance against bile (0.3%) (p = 0.0494), acid (pH 4.5) (p < 0.0001), osmolarity (NaCl 5%, p = 0.0188) and temperature at 50 °C (p = 0.0013) characterized "C. neonatale" strains. Our results showed that "C. neonatale" behaves very differently from C. butyricum and suggests specific responses to environmental changes. Besides it is the first study on clinical isolates for these two anaerobic members of the newborns' gut microbiota and broadens our knowledge about their phenotypic traits.
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Affiliation(s)
| | - G Klein
- EA 4065, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - J Delannoy
- EA 4065, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - L Ferraris
- EA 4065, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - I Friedel
- EA 4065, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - J C Rozé
- Department of Neonatal Medicine, Nantes University Hospital, Nantes, France
| | - M J Butel
- EA 4065, Faculty of Pharmacy, Paris Descartes University, Paris, France
| | - J Aires
- EA 4065, Faculty of Pharmacy, Paris Descartes University, Paris, France.
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Boonma S, Romsang A, Duang-Nkern J, Atichartpongkul S, Trinachartvanit W, Vattanaviboon P, Mongkolsuk S. The FinR-regulated essential gene fprA, encoding ferredoxin NADP+ reductase: Roles in superoxide-mediated stress protection and virulence of Pseudomonas aeruginosa. PLoS One 2017; 12:e0172071. [PMID: 28187184 PMCID: PMC5302815 DOI: 10.1371/journal.pone.0172071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/30/2017] [Indexed: 11/23/2022] Open
Abstract
Pseudomonas aeruginosa has two genes encoding ferredoxin NADP(+) reductases, denoted fprA and fprB. We show here that P. aeruginosa fprA is an essential gene. However, the ΔfprA mutant could only be successfully constructed in PAO1 strains containing an extra copy of fprA on a mini-Tn7 vector integrated into the chromosome or carrying it on a temperature-sensitive plasmid. The strain containing an extra copy of the ferredoxin gene (fdx1) could suppress the essentiality of FprA. Other ferredoxin genes could not suppress the requirement for FprA, suggesting that Fdx1 mediates the essentiality of FprA. The expression of fprA was highly induced in response to treatments with a superoxide generator, paraquat, or sodium hypochlorite (NaOCl). The induction of fprA by these treatments depended on FinR, a LysR-family transcription regulator. In vivo and in vitro analysis suggested that oxidized FinR acted as a transcriptional activator of fprA expression by binding to its regulatory box, located 20 bases upstream of the fprA -35 promoter motif. This location of the FinR box also placed it between the -35 and -10 motifs of the finR promoter, where the reduced regulator functions as a repressor. Under uninduced conditions, binding of FinR repressed its own transcription but had no effect on fprA expression. Exposure to paraquat or NaOCl converted FinR to a transcriptional activator, leading to the expression of both fprA and finR. The ΔfinR mutant showed an increased paraquat sensitivity phenotype and attenuated virulence in the Drosophila melanogaster host model. These phenotypes could be complemented by high expression of fprA, indicating that the observed phenotypes of the ΔfinR mutant arose from the inability to up-regulate fprA expression. In addition, increased expression of fprB was unable to rescue essentiality of fprA or the superoxide-sensitive phenotype of the ΔfinR mutant, suggesting distinct mechanisms of the FprA and FprB enzymes.
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Affiliation(s)
- Siriwan Boonma
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Adisak Romsang
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Jintana Duang-Nkern
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | | | | | - Paiboon Vattanaviboon
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.,Center of Excellence on Environmental Health and Toxicology, CHE, Ministry Of Education, Bangkok, Thailand.,Program in Applied Biological Sciences: Environmental Health, Chulabhorn Graduate Institute, Bangkok, Thailand
| | - Skorn Mongkolsuk
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.,Center of Excellence on Environmental Health and Toxicology, CHE, Ministry Of Education, Bangkok, Thailand.,Center for Emerging Bacterial Infections, Faculty of Science, Mahidol University, Bangkok, Thailand
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Guttenberger N, Blankenfeldt W, Breinbauer R. Recent developments in the isolation, biological function, biosynthesis, and synthesis of phenazine natural products. Bioorg Med Chem 2017; 25:6149-6166. [PMID: 28094222 DOI: 10.1016/j.bmc.2017.01.002] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/29/2016] [Accepted: 01/04/2017] [Indexed: 12/24/2022]
Abstract
Phenazines are natural products which are produced by bacteria or by archaeal Methanosarcina species. The tricyclic ring system enables redox processes, which producing organisms use for oxidation of NADH or for the generation of reactive oxygen species (ROS), giving them advantages over other microorganisms. In this review we summarize the progress in the field since 2005 regarding the isolation of new phenazine natural products, new insights in their biological function, and particularly the now almost completely understood biosynthesis. The review is complemented by a description of new synthetic methods and total syntheses of phenazines.
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Affiliation(s)
- Nikolaus Guttenberger
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria; Institute of Chemistry-Analytical Chemistry, University of Graz, Universitaetsplatz 1, 8010 Graz, Austria
| | - Wulf Blankenfeldt
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany; Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.
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Wang L, Pan Y, Yuan ZH, Zhang H, Peng BY, Wang FF, Qian W. Two-Component Signaling System VgrRS Directly Senses Extracytoplasmic and Intracellular Iron to Control Bacterial Adaptation under Iron Depleted Stress. PLoS Pathog 2016; 12:e1006133. [PMID: 28036380 PMCID: PMC5231390 DOI: 10.1371/journal.ppat.1006133] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 01/12/2017] [Accepted: 12/16/2016] [Indexed: 12/02/2022] Open
Abstract
Both iron starvation and excess are detrimental to cellular life, especially for animal and plant pathogens since they always live in iron-limited environments produced by host immune responses. However, how organisms sense and respond to iron is incompletely understood. Herein, we reveal that in the phytopathogenic bacterium Xanthomonas campestris pv. campestris, VgrS (also named ColS) is a membrane-bound receptor histidine kinase that senses extracytoplasmic iron limitation in the periplasm, while its cognate response regulator, VgrR (ColR), detects intracellular iron excess. Under iron-depleted conditions, dissociation of Fe3+ from the periplasmic sensor region of VgrS activates the VgrS autophosphorylation and subsequent phosphotransfer to VgrR, an OmpR-family transcription factor that regulates bacterial responses to take up iron. VgrR-VgrS regulon and the consensus DNA binding motif of the transcription factor VgrR were dissected by comparative proteomic and ChIP-seq analyses, which revealed that in reacting to iron-depleted environments, VgrR directly or indirectly controls the expressions of hundreds of genes that are involved in various physiological cascades, especially those associated with iron-uptake. Among them, we demonstrated that the phosphorylated VgrR tightly represses the transcription of a special TonB-dependent receptor gene, tdvA. This regulation is a critical prerequisite for efficient iron uptake and bacterial virulence since activation of tdvA transcription is detrimental to these processes. When the intracellular iron accumulates, the VgrR-Fe2+ interaction dissociates not only the binding between VgrR and the tdvA promoter, but also the interaction between VgrR and VgrS. This relieves the repression in tdvA transcription to impede continuous iron uptake and avoids possible toxic effects of excessive iron accumulation. Our results revealed a signaling system that directly senses both extracytoplasmic and intracellular iron to modulate bacterial iron homeostasis. The biological function of iron is like a “double-edge sword” to all cellular life since iron starvation or iron excess leads to cell death. For animal and plant pathogens, they have to compete for iron with their hosts since iron-limitation generally is an immune response against microbial infection. However, how pathogens detect extracellular and intracellular iron concentrations remains unclear. Here we show that a plant bacterial pathogen employs a membrane-bound sensor histidine kinase, VgrS, to directly detect extracytoplasmic iron starvation and activate iron uptake accordingly. As a prerequisite, VgrS phosphorylates cognate VgrR to shut down the transcription of a downstream gene, tdvA, whose expression is harmful to absorb iron and bacterial virulence. However, as intracellular iron concentration increases, the ferrous iron binds to VgrR to release its repression on the tdvA transcription, which results in the block of continuous iron uptake to avoid toxic effect of the metal. Therefore, VgrS and VgrR detect extracytoplasmic and intracellular iron, respectively, and systematically modulate cellular homeostasis to promote bacterial survival in iron-depleted environments, such as in host plant.
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Affiliation(s)
- Li Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yue Pan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhi-Hui Yuan
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Huan Zhang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Bao-Yu Peng
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- School of Biological Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Fang-Fang Wang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wei Qian
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Brinkman CL, Schmidt-Malan SM, Karau MJ, Greenwood-Quaintance K, Hassett DJ, Mandrekar JN, Patel R. Exposure of Bacterial Biofilms to Electrical Current Leads to Cell Death Mediated in Part by Reactive Oxygen Species. PLoS One 2016; 11:e0168595. [PMID: 27992529 PMCID: PMC5167413 DOI: 10.1371/journal.pone.0168595] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 12/02/2016] [Indexed: 01/01/2023] Open
Abstract
Bacterial biofilms may form on indwelling medical devices such as prosthetic joints, heart valves and catheters, causing challenging-to-treat infections. We have previously described the ‘electricidal effect’, in which bacterial biofilms are decreased following exposure to direct electrical current. Herein, we sought to determine if the decreased bacterial quantities are due to detachment of biofilms or cell death and to investigate the role that reactive oxygen species (ROS) play in the observed effect. Using confocal and electron microscopy and flow cytometry, we found that direct current (DC) leads to cell death and changes in the architecture of biofilms formed by Gram-positive and Gram-negative bacteria. Reactive oxygen species (ROS) appear to play a role in DC-associated cell death, as there was an increase in ROS-production by Staphylococcus aureus and Staphylococcus epidermidis biofilms following exposure to DC. An increase in the production of ROS response enzymes catalase and superoxide dismutase (SOD) was observed for S. aureus, S. epidermidis and Pseudomonas aeruginosa biofilms following exposure to DC. Additionally, biofilms were protected from cell death when supplemented with antioxidants and oxidant scavengers, including catalase, mannitol and Tempol. Knocking out SOD (sodAB) in P. aeruginosa led to an enhanced DC effect. Microarray analysis of P. aeruginosa PAO1 showed transcriptional changes in genes related to the stress response and cell death. In conclusion, the electricidal effect results in death of bacteria in biofilms, mediated, at least in part, by production of ROS.
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Affiliation(s)
- Cassandra L. Brinkman
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Suzannah M. Schmidt-Malan
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Melissa J. Karau
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Kerryl Greenwood-Quaintance
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Daniel J. Hassett
- Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States of America
| | - Jayawant N. Mandrekar
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research Mayo Clinic, Rochester, MN, United States of America
| | - Robin Patel
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
- Division of Infectious Diseases, Department of Medicine, Mayo Clinic, Rochester, MN, United States of America
- * E-mail:
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Abbas HA, Shaldam MA. Glyceryl trinitrate is a novel inhibitor of quorum sensing in Pseudomonas aeruginosa. Afr Health Sci 2016; 16:1109-1117. [PMID: 28479904 DOI: 10.4314/ahs.v16i4.29] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Targeting quorum sensing is an alternative approach to antibiotics.Targeting quorum sensing-regulated virulence will disarm the pathogen without exerting pressure on its growth. As a result, emergence of resistance is avoided and the immune system can easily eradicate bacteria. OBJECTIVES Investigation of the possible inhibition of quorum sensing-regulated virulence of Pseudomonas aeruginosa by glyceryltrinitrate. METHODS The quorum sensing inhibiting activity of glyceryl trinitrate was assessed by inhibition of violacein production in Chromobacterium violaceum ATCC 12472. Its ability to inhibit pyocyanin, protease, biofilm and tolerance to oxidative stress was evaluated. Docking study was performed to study the interference of glyceryl trinitrate with the binding of autoinducers with LasR and rhlR receptors. RESULTS Glyceryl trinitrate exerted a significant biofilm inhibiting and eradicating activities. It decreased the production of quorum-sensing dependent violacein production. It significantly inhibited the production of pyocyanin and protease and diminished the tolerance against oxidative stress. Molecular docking study showed that glyceryl trinitrate interferes with the binding of autoinducers to their receptors. It could bind to Las Rand rhlr receptors with binding energy of -93.47 and -77.23, respectively. CONCLUSION Glyceryl trinitrate can be an antivirulence agent in the treatment of Pseudomonas aeruginosa topical infections such as burn infections.
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Affiliation(s)
- Hisham A Abbas
- Department of Microbiology and Immunology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
| | - Moutaz A Shaldam
- Department of Medicinal Chemistry, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
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40
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Zhao X, Chen C, Jiang X, Shen W, Huang G, Le S, Lu S, Zou L, Ni Q, Li M, Zhao Y, Wang J, Rao X, Hu F, Tan Y. Transcriptomic and Metabolomic Analysis Revealed Multifaceted Effects of Phage Protein Gp70.1 on Pseudomonas aeruginosa. Front Microbiol 2016; 7:1519. [PMID: 27725812 PMCID: PMC5035744 DOI: 10.3389/fmicb.2016.01519] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 09/12/2016] [Indexed: 12/13/2022] Open
Abstract
The impact of phage infection on the host cell is severe. In order to take over the cellular machinery, some phage proteins were produced to shut off the host biosynthesis early in the phage infection. The discovery and identification of these phage-derived inhibitors have a significant prospect of application in antibacterial treatment. This work presented a phage protein, gp70.1, with non-specific inhibitory effects on Pseudomonas aeruginosa and Escherichia coli. Gp70.1 was encoded by early gene – orf 70.1 from P. aeruginosa phage PaP3. The P. aeruginosa with a plasmid encoding gp70.1 showed with delayed growth and had the appearance of a small colony. The combination of multifaceted analysis including microarray-based transcriptomic analysis, RT-qPCR, nuclear magnetic resonance (NMR) spectroscopy-based metabolomics and phenotype experiments were performed to investigate the effects of gp70.1 on P. aeruginosa. A total of 178 genes of P. aeruginosa mainly involved in extracellular function and metabolism were differentially expressed in the presence of gp70.1 at three examined time points. Furthermore, our results indicated that gp70.1 had an extensive impact on the extracellular phenotype of P. aeruginosa, such as motility, pyocyanin, extracellular protease, polysaccharide, and cellulase. For the metabolism of P. aeruginosa, the main effect of gp70.1 was the reduction of amino acid consumption. Finally, the RNA polymerase sigma factor RpoS was identified as a potential cellular target of gp70.1. Gp70.1 was the first bacterial inhibitor identified from Pseudomonas aeruginosa phage PaP3. It was also the first phage protein that interacted with the global regulator RpoS of bacteria. Our results indicated the potential value of gp70.1 in antibacterial applications. This study preliminarily revealed the biological function of gp70.1 and provided a reference for the study of other phage genes sharing similarities with orf70.1.
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Affiliation(s)
- Xia Zhao
- Department of Microbiology, Third Military Medical University Chongqing, China
| | | | - Xingyu Jiang
- Department of Clinical Laboratory, Xinqiao Hospital, Third Military Medical University Chongqing, China
| | - Wei Shen
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Guangtao Huang
- Institute of Burn Research, Southwest Hospital, Third Military Medical University Chongqing, China
| | - Shuai Le
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Shuguang Lu
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Lingyun Zou
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Qingshan Ni
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Ming Li
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Yan Zhao
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Jing Wang
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Xiancai Rao
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Fuquan Hu
- Department of Microbiology, Third Military Medical University Chongqing, China
| | - Yinling Tan
- Department of Microbiology, Third Military Medical University Chongqing, China
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Sethupathy S, Prasath KG, Ananthi S, Mahalingam S, Balan SY, Pandian SK. Proteomic analysis reveals modulation of iron homeostasis and oxidative stress response in Pseudomonas aeruginosa PAO1 by curcumin inhibiting quorum sensing regulated virulence factors and biofilm production. J Proteomics 2016; 145:112-126. [DOI: 10.1016/j.jprot.2016.04.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Revised: 04/15/2016] [Accepted: 04/17/2016] [Indexed: 01/01/2023]
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42
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Antioxidant Defense Mechanisms in Pseudomonas aeruginosa: Role of Iron-Cofactored Superoxide Dismutase in Response to UV-C Radiations. Curr Microbiol 2016; 73:159-64. [DOI: 10.1007/s00284-016-1043-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 03/09/2016] [Indexed: 11/26/2022]
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43
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Park AJ, Murphy K, Surette MD, Bandoro C, Krieger JR, Taylor P, Khursigara CM. Tracking the Dynamic Relationship between Cellular Systems and Extracellular Subproteomes in Pseudomonas aeruginosa Biofilms. J Proteome Res 2015; 14:4524-37. [PMID: 26378716 DOI: 10.1021/acs.jproteome.5b00262] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The transition of the opportunistic pathogen Pseudomonas aeruginosa from free-living bacteria into surface-associated biofilm communities represents a viable target for the prevention and treatment of chronic infectious disease. We have established a proteomics platform that identified 2443 and 1142 high-confidence proteins in P. aeruginosa whole cells and outer-membrane vesicles (OMVs), respectively, at three time points during biofilm development (ProteomeXchange identifier PXD002605). The analysis of cellular systems, specifically the phenazine biosynthetic pathway, demonstrates that whole-cell protein abundance correlates to end product (i.e., pyocyanin) concentrations in biofilm but not in planktonic cultures. Furthermore, increased cellular protein abundance in this pathway results in quantifiable pyocyanin in early biofilm OMVs and OMVs from both growth modes isolated at later time points. Overall, our data indicate that the OMVs being released from the surface of the biofilm whole cells have unique proteomes in comparison to their planktonic counterparts. The relative abundance of OMV proteins from various subcellular sources showed considerable differences between the two growth modes over time, supporting the existence and preferential activation of multiple OMV biogenesis mechanisms under different conditions. The consistent detection of cytoplasmic proteins in all of the OMV subproteomes challenges the notion that OMVs are composed of outer membrane and periplasmic proteins alone. Direct comparisons of outer-membrane protein abundance levels between OMVs and whole cells shows ratios that vary greatly from 1:1 and supports previous studies that advocate the specific inclusion, or "packaging", of proteins into OMVs. The quantitative analysis of packaged protein groups suggests biogenesis mechanisms that involve untethered, rather than absent, peptidoglycan-binding proteins. Collectively, individual protein and biological system analyses of biofilm OMVs show that drug-binding cytoplasmic proteins and porins are potentially shuttled from the whole cell into the OMVs and may contribute to the antibiotic resistance of P. aeruginosa whole cells within biofilms.
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Affiliation(s)
- Amber J Park
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada , N1G 2W1
| | - Kathleen Murphy
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada , N1G 2W1
| | - Matthew D Surette
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada , N1G 2W1
| | - Christopher Bandoro
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada , N1G 2W1
| | - Jonathan R Krieger
- SPARC BioCentre, The Hospital for Sick Children , Toronto, Ontario, Canada , M5G 0A4
| | - Paul Taylor
- SPARC BioCentre, The Hospital for Sick Children , Toronto, Ontario, Canada , M5G 0A4
| | - Cezar M Khursigara
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario, Canada , N1G 2W1
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Ranjani J, Pushpanathan M, Mahesh A, Niraimathi M, Gunasekaran P, Rajendhran J. Pseudomonas aeruginosa PAO1 induces distinct cell death mechanisms in H9C2 cells and its differentiated form. J Basic Microbiol 2015; 55:1191-202. [PMID: 26011149 DOI: 10.1002/jobm.201500037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 05/02/2015] [Indexed: 12/23/2022]
Abstract
Bacterial infections in myocardium may lead to the myocardial damage, which may progress to dilated cardiomyopathy and cardiac arrest. Pseudomonas aeruginosa has been reported to cause myocarditis and other systemic infections especially in immunocompromised patients. To understand the cellular responses during the establishment of infection in myocardium, we challenged differentiated H9C2 cells with P. aeruginosa PAO1. We also did comparison studies with infected undifferentiated form of H9C2 cells. Invasion studies revealed that PAO1 can invade both forms of cells and is able to survive and replicate within the host. Internalization of PAO1 was confirmed by live cell imaging and flow cytometry analysis. Though invasion of the pathogen triggered an increased ROS production in the host cells at earlier post-infection periods, it was decreased at later post-infection periods. Invasion of PAO1 induced cell death through apoptosis in differentiated H9C2 cells. Significant decrease in cell size, formation of polarized mitochondria, and nuclear fragmentation were observed in the infected differentiated cells. On the contrary, cell death preceded by multinucleation was observed in infected undifferentiated H9C2 cells. Morphological markers such as multinuclei and micro nuclei were observed. Cell cycle arrest in G2/M phase corroborates that the undifferentiated H9C2 cells experienced cell death preceded by multinucleation.
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Affiliation(s)
- Jothi Ranjani
- Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Muthuirulan Pushpanathan
- Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Ayyavu Mahesh
- IPLS Program, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Marimuthu Niraimathi
- IPLS Program, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Paramasamy Gunasekaran
- Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India.,Thiruvalluvar University, Vellore, Tamil Nadu, India
| | - Jeyaprakash Rajendhran
- Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
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Mousa WK, Raizada MN. Biodiversity of genes encoding anti-microbial traits within plant associated microbes. FRONTIERS IN PLANT SCIENCE 2015; 6:231. [PMID: 25914708 PMCID: PMC4392301 DOI: 10.3389/fpls.2015.00231] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 03/23/2015] [Indexed: 05/10/2023]
Abstract
The plant is an attractive versatile home for diverse associated microbes. A subset of these microbes produces a diversity of anti-microbial natural products including polyketides, non-ribosomal peptides, terpenoids, heterocylic nitrogenous compounds, volatile compounds, bacteriocins, and lytic enzymes. In recent years, detailed molecular analysis has led to a better understanding of the underlying genetic mechanisms. New genomic and bioinformatic tools have permitted comparisons of orthologous genes between species, leading to predictions of the associated evolutionary mechanisms responsible for diversification at the genetic and corresponding biochemical levels. The purpose of this review is to describe the biodiversity of biosynthetic genes of plant-associated bacteria and fungi that encode selected examples of antimicrobial natural products. For each compound, the target pathogen and biochemical mode of action are described, in order to draw attention to the complexity of these phenomena. We review recent information of the underlying molecular diversity and draw lessons through comparative genomic analysis of the orthologous coding sequences (CDS). We conclude by discussing emerging themes and gaps, discuss the metabolic pathways in the context of the phylogeny and ecology of their microbial hosts, and discuss potential evolutionary mechanisms that led to the diversification of biosynthetic gene clusters.
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Affiliation(s)
- Walaa K. Mousa
- Department of Plant Agriculture, University of GuelphGuelph, ON, Canada
- Department of Pharmacognosy, Faculty of Pharmacy, Mansoura UniversityMansoura, Egypt
| | - Manish N. Raizada
- Department of Plant Agriculture, University of GuelphGuelph, ON, Canada
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46
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General and condition-specific essential functions of Pseudomonas aeruginosa. Proc Natl Acad Sci U S A 2015; 112:5189-94. [PMID: 25848053 DOI: 10.1073/pnas.1422186112] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The essential functions of a bacterial pathogen reflect the most basic processes required for its viability and growth, and represent potential therapeutic targets. Most screens for essential genes have assayed a single condition--growth in a rich undefined medium--and thus have not distinguished genes that are generally essential from those that are specific to this particular condition. To help define these classes for Pseudomonas aeruginosa, we identified genes required for growth on six different media, including a medium made from cystic fibrosis patient sputum. The analysis used the Tn-seq circle method to achieve high genome coverage and analyzed more than 1,000,000 unique insertion positions (an average of one insertion every 6.0 bp). We identified 352 general and 199 condition-specific essential genes. A subset of assignments was verified in individual strains with regulated expression alleles. The profile of essential genes revealed that, compared with Escherichia coli, P. aeruginosa is highly vulnerable to mutations disrupting central carbon-energy metabolism and reactive oxygen defenses. These vulnerabilities may arise from the stripped-down architecture of the organism's carbohydrate utilization pathways and its reliance on respiration for energy generation. The essential function profile thus provides fundamental insights into P. aeruginosa physiology as well as identifying candidate targets for new antibacterial agents.
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47
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Sakamoto A, Terui Y, Horie C, Fukui T, Masuzawa T, Sugawara S, Shigeta K, Shigeta T, Igarashi K, Kashiwagi K. Antibacterial effects of protruding and recessed shark skin micropatterned surfaces of polyacrylate plate with a shallow groove. FEMS Microbiol Lett 2014; 361:10-16. [DOI: 10.1111/1574-6968.12604] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 09/15/2014] [Accepted: 09/15/2014] [Indexed: 12/01/2022] Open
Affiliation(s)
- Akihiko Sakamoto
- Faculty of Pharmacy; Chiba Institute of Science; Choshi Chiba Japan
| | - Yusuke Terui
- Faculty of Pharmacy; Chiba Institute of Science; Choshi Chiba Japan
| | - Chihiro Horie
- Faculty of Pharmacy; Chiba Institute of Science; Choshi Chiba Japan
| | - Takashi Fukui
- Faculty of Pharmacy; Chiba Institute of Science; Choshi Chiba Japan
| | | | | | | | | | | | - Keiko Kashiwagi
- Faculty of Pharmacy; Chiba Institute of Science; Choshi Chiba Japan
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48
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Involvement of stress-related genes polB and PA14_46880 in biofilm formation of Pseudomonas aeruginosa. Infect Immun 2014; 82:4746-57. [PMID: 25156741 DOI: 10.1128/iai.01915-14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chronic infections of Pseudomonas aeruginosa are generally established through production of biofilm. During biofilm formation, production of an extracellular matrix and establishment of a distinct bacterial phenotype make these infections difficult to eradicate. However, biofilm studies have been hampered by the fact that most assays utilize nonliving surfaces as biofilm attachment substrates. In an attempt to better understand the mechanisms behind P. aeruginosa biofilm formation, we performed a genetic screen to identify novel factors involved in biofilm formation on biotic and abiotic surfaces. We found that deletion of genes polB and PA14_46880 reduced biofilm formation significantly compared to that in the wild-type strain PA14 in an abiotic biofilm system. In a biotic biofilm model, wherein biofilms form on cultured airway cells, the ΔpolB and ΔPA14_46880 strains showed increased cytotoxic killing of the airway cells independent of the total number of bacteria bound. Notably, deletion mutant strains were more resistant to ciprofloxacin treatment. This phenotype was linked to decreased expression of algR, an alginate transcriptional regulatory gene, under ciprofloxacin pressure. Moreover, we found that pyocyanin production was increased in planktonic cells of mutant strains. These results indicate that inactivation of polB and PA14_46880 may inhibit transition of P. aeruginosa from a more acute infection lifestyle to the biofilm phenotype. Future investigation of these genes may lead to a better understanding of P. aeruginosa biofilm formation and chronic biofilm infections.
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49
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Resveratrol induced inhibition of Escherichia coli proceeds via membrane oxidation and independent of diffusible reactive oxygen species generation. Redox Biol 2014; 2:865-72. [PMID: 25009788 PMCID: PMC4087184 DOI: 10.1016/j.redox.2014.06.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 06/06/2014] [Accepted: 06/11/2014] [Indexed: 11/22/2022] Open
Abstract
Resveratrol (5-[(E)-2-(4-hydroxyphenyl)ethenyl]benzene-1,3-diol), a redox active phytoalexin with a large number of beneficial activities is also known for antibacterial property. However the mechanism of action of resveratrol against bacteria remains unknown. Due to its extensive redox property it was envisaged if reactive oxygen species (ROS) generation by resveratrol could be a reason behind its antibacterial activity. Employing Escherichia coli as a model organism we have evaluated the role of diffusible reactive oxygen species in the events leading to inhibition of this organism by resveratrol. Evidence for the role of ROS in E. coli treated with resveratrol was investigated by direct quantification of ROS by flow cytometry, supplementation with ROS scavengers, depletion of intracellular glutathione, employing mutants devoid of enzymatic antioxidant defences, induction of adaptive response prior to resveratrol challenge and monitoring oxidative stress response elements oxyR, soxS and soxR upon resveratrol treatment. Resveratrol treatment did not result in scavengable ROS generation in E. coli cells. However, evidence towards membrane damage was obtained by potassium leakage (atomic absorption spectrometry) and propidium iodide uptake (flow cytometry and microscopy) as an early event. Based on the comprehensive evidences this study concludes for the first time the antibacterial property of resveratrol against E. coli does not progress via the diffusible ROS but is mediated by site-specific oxidative damage to the cell membrane as the primary event. Resveratrol possesses antibacterial property among a myriad of properties. However the reasons behind its antibacterial property remains poorly understood. We investigated the role of its redox property against the bacterium Escherichia coli. We reveal the process is free of diffusible reactive oxygen species (ROS). The initial event encompasses membrane damage.
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50
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Intarak N, Muangsombut V, Vattanaviboon P, Stevens MP, Korbsrisate S. Growth, motility and resistance to oxidative stress of the melioidosis pathogenBurkholderia pseudomalleiare enhanced by epinephrine. Pathog Dis 2014; 72:24-31. [DOI: 10.1111/2049-632x.12181] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 03/28/2014] [Accepted: 04/10/2014] [Indexed: 01/07/2023] Open
Affiliation(s)
- Narin Intarak
- Department of Immunology; Faculty of Medicine Siriraj Hospital; Mahidol University; Bangkok Thailand
| | - Veerachat Muangsombut
- Department of Immunology; Faculty of Medicine Siriraj Hospital; Mahidol University; Bangkok Thailand
| | | | - Mark P. Stevens
- The Roslin Institute & Royal (Dick) School of Veterinary Studies; University of Edinburgh; Edinburgh UK
| | - Sunee Korbsrisate
- Department of Immunology; Faculty of Medicine Siriraj Hospital; Mahidol University; Bangkok Thailand
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