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Sharma A, Shuppara AM, Padron GC, Sanfilippo JE. Combining multiple stressors unexpectedly blocks bacterial migration and growth. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.27.595753. [PMID: 38853869 PMCID: PMC11160647 DOI: 10.1101/2024.05.27.595753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
In nature, organisms experience combinations of stressors. However, laboratory studies typically simplify reality and focus on the effects of an individual stressor. Here, we use a microfluidic approach to simultaneously provide a physical stressor (shear flow) and a chemical stressor (H 2 O 2 ) to the human pathogen Pseudomonas aeruginosa . By treating cells with levels of flow and H 2 O 2 that commonly co-occur in nature, we discover that previous reports significantly overestimate the H 2 O 2 levels required to block bacterial growth. Specifically, we establish that flow increases H 2 O 2 effectiveness 50-fold, explaining why previous studies lacking flow required much higher concentrations. Using natural H 2 O 2 levels, we identify the core H 2 O 2 regulon, characterize OxyR-mediated dynamic regulation, and dissect the redundant roles of multiple H 2 O 2 scavenging systems. By examining single-cell behavior, we serendipitously discover that the combined effects of H 2 O 2 and flow block pilus-driven surface migration. Thus, our results counter previous studies and reveal that natural levels of H 2 O 2 and flow synergize to restrict bacterial colonization and survival. By studying two stressors at once, our research highlights the limitations of oversimplifying nature and demonstrates that physical and chemical stress can combine to yield unpredictable effects.
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2
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Goodyear MC, Seidel L, Krieger JR, Geddes-McAlister J, Levesque RC, Khursigara CM. Quantitative proteomics reveals unique responses to antimicrobial treatments in clinical Pseudomonas aeruginosa isolates. mSystems 2023; 8:e0049123. [PMID: 37623324 PMCID: PMC10654054 DOI: 10.1128/msystems.00491-23] [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: 05/24/2023] [Accepted: 07/05/2023] [Indexed: 08/26/2023] Open
Abstract
IMPORTANCE Pseudomonas aeruginosa is an important pathogen often associated with hospital-acquired infections and chronic lung infections in people with cystic fibrosis. P. aeruginosa possesses a wide array of intrinsic and adaptive mechanisms of antibiotic resistance, and the regulation of these mechanisms is complex. Label-free quantitative proteomics is a powerful tool to compare susceptible and resistant strains of bacteria and their responses to antibiotic treatments. Here we compare the proteomes of three isolates of P. aeruginosa with different antibiotic resistance profiles in response to five challenge conditions. We uncover unique and shared proteome changes for the widely used laboratory strain PAO1 and two isolates of the Liverpool epidemic strain of P. aeruginosa, LESlike1 and LESB58. Our data set provides insight into antibiotic resistance in clinically relevant Pseudomonas isolates and highlights proteins, including those with uncharacterized functions, which can be further investigated for their role in adaptive responses to antibiotic treatments.
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Affiliation(s)
- Mara C. Goodyear
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Laura Seidel
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | | | | | - Roger C. Levesque
- Institut de biologie integrative et des systems (IBIS), Département de microbiologie-infectiologie et d'immunologie, Université Laval, Laval, Quebec, Canada
| | - Cezar M. Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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3
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Padron GC, Shuppara AM, Sharma A, Koch MD, Palalay JJS, Radin JN, Kehl-Fie TE, Imlay JA, Sanfilippo JE. Shear rate sensitizes bacterial pathogens to H 2O 2 stress. Proc Natl Acad Sci U S A 2023; 120:e2216774120. [PMID: 36888662 PMCID: PMC10089187 DOI: 10.1073/pnas.2216774120] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 01/18/2023] [Indexed: 03/09/2023] Open
Abstract
Cells regularly experience fluid flow in natural systems. However, most experimental systems rely on batch cell culture and fail to consider the effect of flow-driven dynamics on cell physiology. Using microfluidics and single-cell imaging, we discover that the interplay of physical shear rate (a measure of fluid flow) and chemical stress trigger a transcriptional response in the human pathogen Pseudomonas aeruginosa. In batch cell culture, cells protect themselves by quickly scavenging the ubiquitous chemical stressor hydrogen peroxide (H2O2) from the media. In microfluidic conditions, we observe that cell scavenging generates spatial gradients of H2O2. High shear rates replenish H2O2, abolish gradients, and generate a stress response. Combining mathematical simulations and biophysical experiments, we find that flow triggers an effect like "wind-chill" that sensitizes cells to H2O2 concentrations 100 to 1,000 times lower than traditionally studied in batch cell culture. Surprisingly, the shear rate and H2O2 concentration required to generate a transcriptional response closely match their respective values in the human bloodstream. Thus, our results explain a long-standing discrepancy between H2O2 levels in experimental and host environments. Finally, we demonstrate that the shear rate and H2O2 concentration found in the human bloodstream trigger gene expression in the blood-relevant human pathogen Staphylococcus aureus, suggesting that flow sensitizes bacteria to chemical stress in natural environments.
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Affiliation(s)
- Gilberto C. Padron
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Alexander M. Shuppara
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Anuradha Sharma
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Matthias D. Koch
- Department of Biology, Texas A&M University, College Station, TX77843
| | | | - Jana N. Radin
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Thomas E. Kehl-Fie
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - James A. Imlay
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL61801
| | - Joseph E. Sanfilippo
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL61801
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4
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Pseudomonas aeruginosa H3-T6SS Combats H 2O 2 Stress by Diminishing the Amount of Intracellular Unincorporated Iron in a Dps-Dependent Manner and Inhibiting the Synthesis of PQS. Int J Mol Sci 2023; 24:ijms24021614. [PMID: 36675127 PMCID: PMC9866239 DOI: 10.3390/ijms24021614] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/28/2022] [Accepted: 01/10/2023] [Indexed: 01/17/2023] Open
Abstract
The type VI secretion system (T6SS), a protein translocation nanomachine, is widely distributed in Gram-negative bacteria and delivers effectors directly into target cells or the extracellular environment to help the bacteria gain a competitive fitness advantage and promote bacterial survival in harmful environments. In this study, we demonstrated that the synthesis of the Pseudomonas quinolone signal (PQS) in Pseudomonas aeruginosa PAO1 was inhibited by the H3-T6SS gene cluster under iron-rich conditions, and that this inhibition was relieved under iron starvation conditions. Conversely, PQS differentially regulated the expression of the H3-T6SS structural genes and the effector protein gene tseF. The expression of tseF was inhibited by PQS, while the expressions of the H3-T6SS structural genes were positively regulated by PQS. Further studies showed that the H3-T6SS was involved in the resistance of P. aeruginosa to oxidative stress caused by hydrogen peroxide (H2O2). Interestingly, H3-T6SS expression was neither induced by H2O2 stress nor regulated by OxyR (a global anti-oxidative transcriptional regulator) but was positively regulated by RpoS (a major transcription regulator of the stress response). In addition, we found that the clpV3 (a structural gene of H3-T6SS) mutation resulted in upregulation of two proteins related to PQS synthesis and many proteins related to oxidative stress resistance, while the expression of some iron storage proteins, especially Dps, were significantly downregulated. Furthermore, the clpV3 mutation led to an increase in the intracellular free Fe2+ content of P. aeruginosa. Further studies showed that both the PQS deficient mutation and overexpression of dps effectively restored the H2O2 sensitive phenotype of the H3-T6SS mutant. Finally, we proposed the following model of H3-T6SS-mediated resistance to H2O2 stress in P. aeruginosa. H3-T6SS not only reduces the intracellular free Fe2+ level by upregulating the expression of ferritin Dps, but also inhibits the synthesis of PQS to mediate the resistance of P. aeruginosa to H2O2 stress. This study highlights the important role of H3-T6SS in the ability of P. aeruginosa to combat H2O2 stress and provides a perspective for understanding the stress response mechanism of bacteria.
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The Pseudomonas aeruginosa RpoH (σ 32) Regulon and Its Role in Essential Cellular Functions, Starvation Survival, and Antibiotic Tolerance. Int J Mol Sci 2023; 24:ijms24021513. [PMID: 36675051 PMCID: PMC9866376 DOI: 10.3390/ijms24021513] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/23/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
The bacterial heat-shock response is regulated by the alternative sigma factor, σ32 (RpoH), which responds to misfolded protein stress and directs the RNA polymerase to the promoters for genes required for protein refolding or degradation. In P. aeruginosa, RpoH is essential for viability under laboratory growth conditions. Here, we used a transcriptomics approach to identify the genes of the RpoH regulon, including RpoH-regulated genes that are essential for P. aeruginosa. We placed the rpoH gene under control of the arabinose-inducible PBAD promoter, then deleted the chromosomal rpoH allele. This allowed transcriptomic analysis of the RpoH (σ32) regulon following a short up-shift in the cellular concentration of RpoH by arabinose addition, in the absence of a sudden change in temperature. The P. aeruginosa ∆rpoH (PBAD-rpoH) strain grew in the absence of arabinose, indicating that some rpoH expression occurred without arabinose induction. When arabinose was added, the rpoH mRNA abundance of P. aeruginosa ∆rpoH (PBAD-rpoH) measured by RT-qPCR increased five-fold within 15 min of arabinose addition. Transcriptome results showed that P. aeruginosa genes required for protein repair or degradation are induced by increased RpoH levels, and that many genes essential for P. aeruginosa growth are induced by RpoH. Other stress response genes induced by RpoH are involved in damaged nucleic acid repair and in amino acid metabolism. Annotation of the hypothetical proteins under RpoH control included proteins that may play a role in antibiotic resistances and in non-ribosomal peptide synthesis. Phenotypic analysis of P. aeruginosa ∆rpoH (PBAD-rpoH) showed that it is impaired in its ability to survive during starvation compared to the wild-type strain. P. aeruginosa ∆rpoH (PBAD-rpoH) also had increased sensitivity to aminoglycoside antibiotics, but not to other classes of antibiotics, whether cultured planktonically or in biofilms. The enhanced aminoglycoside sensitivity of the mutant strain may be due to indirect effects, such as the build-up of toxic misfolded proteins, or to the direct effect of genes, such as aminoglycoside acetyl transferases, that are regulated by RpoH. Overall, the results demonstrate that RpoH regulates genes that are essential for viability of P. aeruginosa, that it protects P. aeruginosa from damage from aminoglycoside antibiotics, and that it is required for survival during nutrient-limiting conditions.
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Hu Y, Kang Y, Huang F, Su Y, Zhou X, Wang AJ, Gao SH. Distinct responses of Pseudomonas aeruginosa PAO1 exposed to different levels of polystyrene nanoplastics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 852:158214. [PMID: 36028032 DOI: 10.1016/j.scitotenv.2022.158214] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/18/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Large amounts of discarded plastics in the environment can be aged into microplastics and nanoplastics, which are not easily removed, posing potential nonnegligible risks to the ecosystem and human health. Although previous studies have revealed that nanoplastics have detrimental impacts on microorganisms, the potential molecular mechanisms of nanoplastic particles' effect on microbial growth and metabolism are still lacking. Here, multiple responses of Pseudomonas aeruginosa PAO1 (PAO1) to different levels of polystyrene nanoplastics (PS NPs) exposure were investigated by physiological experiments, live/dead staining, redox status, and genome-wide RNA sequencing. The results showed that PS NPs had dual effects on PAO1, and different concentrations of PS NPs demonstrated different effects on the growth and metabolism of PAO1. All levels of PS NPs had no obvious biocidal effect on PAO1. The production and consumption of ROS were in dynamic equilibrium and could be regulated genetically to ensure that the ROS level was in the biotolerable range. 20 and 50 mg/L of PS NPs severely inhibited the nitrate reduction, while 0.1 mg/L of PS NPs promoted the denitrification and TCA cycle. Meanwhile, 20 and 50 mg/L of PS NPs resulted in intense down-regulation of genes involved in denitrification. In contrast, the expression of genes involved in respiration is promoted with generated energy to withstand stress from high-level PS NPs, coinciding with the physiological results. In addition, our results showed that PS NPs concentrations of 20 and 50 mg/L exposure substantially up-regulated the expression of genes encoding for flagellar biosynthesis and biofilm formation to tackle the stress. Our findings would provide new insights into the interactions between environmental bacteria and PS NPs at the transcriptional level, thereby enhancing our understanding of the potential risks of PS NPs to microbial ecosystems and public health.
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Affiliation(s)
- Yuxin Hu
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Yuanyuan Kang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Fang Huang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China; State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Yiyi Su
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Xu Zhou
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Ai-Jie Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Shu-Hong Gao
- State Key Laboratory of Urban Water Resource and Environment, School of Civil & Environmental Engineering, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China.
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Salgado MG, Demina IV, Maity PJ, Nagchowdhury A, Caputo A, Krol E, Loderer C, Muth G, Becker A, Pawlowski K. Legume NCRs and nodule-specific defensins of actinorhizal plants—Do they share a common origin? PLoS One 2022; 17:e0268683. [PMID: 35980975 PMCID: PMC9387825 DOI: 10.1371/journal.pone.0268683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 05/04/2022] [Indexed: 11/20/2022] Open
Abstract
The actinorhizal plant Datisca glomerata (Datiscaceae, Cucurbitales) establishes a root nodule symbiosis with actinobacteria from the earliest branching symbiotic Frankia clade. A subfamily of a gene family encoding nodule-specific defensin-like cysteine-rich peptides is highly expressed in D. glomerata nodules. Phylogenetic analysis of the defensin domain showed that these defensin-like peptides share a common evolutionary origin with nodule-specific defensins from actinorhizal Fagales and with nodule-specific cysteine-rich peptides (NCRs) from legumes. In this study, the family member with the highest expression levels, DgDef1, was characterized. Promoter-GUS studies on transgenic hairy roots showed expression in the early stage of differentiation of infected cells, and transient expression in the nodule apex. DgDef1 contains an N-terminal signal peptide and a C-terminal acidic domain which are likely involved in subcellular targeting and do not affect peptide activity. In vitro studies with E. coli and Sinorhizobium meliloti 1021 showed that the defensin domain of DgDef1 has a cytotoxic effect, leading to membrane disruption with 50% lethality for S. meliloti 1021 at 20.8 μM. Analysis of the S. meliloti 1021 transcriptome showed that, at sublethal concentrations, DgDef1 induced the expression of terminal quinol oxidases, which are associated with the oxidative stress response and are also expressed during symbiosis. Overall, the changes induced by DgDef1 are reminiscent of those of some legume NCRs, suggesting that nodule-specific defensin-like peptides were part of the original root nodule toolkit and were subsequently lost in most symbiotic legumes, while being maintained in the actinorhizal lineages.
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Affiliation(s)
- Marco Guedes Salgado
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Irina V Demina
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Pooja Jha Maity
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Anurupa Nagchowdhury
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Andrea Caputo
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Elizaveta Krol
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Christoph Loderer
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Günther Muth
- Department of Microbial Bioactive Compounds, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), Eberhard Karls University Tübingen, Tübingen, Germany
| | - Anke Becker
- Center for Synthetic Microbiology, Philipps-Universität Marburg, Marburg, Germany
- Department of Biology, Philipps-Universität Marburg, Marburg, Germany
| | - Katharina Pawlowski
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
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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: 30] [Impact Index Per Article: 10.0] [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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Mitchell AB, Glanville AR. The Impact of Resistant Bacterial Pathogens including Pseudomonas aeruginosa and Burkholderia on Lung Transplant Outcomes. Semin Respir Crit Care Med 2021; 42:436-448. [PMID: 34030205 DOI: 10.1055/s-0041-1728797] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2022]
Abstract
Pseudomonas and Burkholderia are gram-negative organisms that achieve colonization within the lungs of patients with cystic fibrosis, and are associated with accelerated pulmonary function decline. Multidrug resistance is a hallmark of these organisms, which makes eradication efforts difficult. Furthermore, the literature has outlined increased morbidity and mortality for lung transplant (LTx) recipients infected with these bacterial genera. Indeed, many treatment centers have considered Burkholderia cepacia infection an absolute contraindication to LTx. Ongoing research has delineated different species within the B. cepacia complex (BCC), with significantly varied morbidity and survival profiles. This review considers the current evidence for LTx outcomes between the different subspecies encompassed within these genera as well as prophylactic and management options. The availability of meta-genomic tools will make differentiation between species within these groups easier in the future, and will allow more evidence-based decisions to be made regarding suitability of candidates colonized with these resistant bacteria for LTx. This review suggests that based on the current evidence, not all species of BCC should be considered contraindications to LTx, going forward.
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Affiliation(s)
- Alicia B Mitchell
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Allan R Glanville
- Lung Transplant Unit, St. Vincent's Hospital, Sydney, New South Wales, Australia
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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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Oxidative Stress Produced by Paraquat Reduces Nitrogen Fixation in Soybean-Bradyrhizobium diazoefficiens Symbiosis by Decreasing Nodule Functionality. NITROGEN 2021. [DOI: 10.3390/nitrogen2010003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Soybean (Glycine max.) is one of the most important legumes cultivated worldwide. Its productivity can be altered by some biotic and abiotic stresses like global warming, soil metal pollution or over-application of herbicides like paraquat (1,1’-dimethyl-4,4’-bipyridinium dichloride). In this study, the effect of oxidative stress produced by paraquat addition (0, 20, 50 and 100 µM) during plant growth on symbiotic nitrogen fixation (SNF) and functionality of Bradyrhizobium diazoefficiens-elicited soybean nodules were evaluated. Results showed that the 50 µM was the threshold that B. diazoefficiens can tolerate under free-living conditions. In symbiosis with soybean, the paraquat addition statistically reduced the shoot and root dry weight of soybean plants, and number and development of the nodules. SNF was negatively affected by paraquat, which reduced total nitrogen content and fixed nitrogen close to 50% when 100 µM was added. These effects were due to the impairment of nodule functionality and the increased oxidative status of the nodules, as revealed by the lower leghaemoglobin content and the higher lipid peroxidation in soybean nodules from paraquat-treated plants.
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12
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Augustyniak A, Cendrowski K, Grygorcewicz B, Jabłońska J, Nawrotek P, Trukawka M, Mijowska E, Popowska M. The Response of Pseudomonas aeruginosa PAO1 to UV-activated Titanium Dioxide/Silica Nanotubes. Int J Mol Sci 2020; 21:E7748. [PMID: 33092046 PMCID: PMC7590050 DOI: 10.3390/ijms21207748] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/15/2020] [Accepted: 10/16/2020] [Indexed: 11/29/2022] Open
Abstract
Pseudomonas aeruginosa is a bacterium of high clinical and biotechnological importance thanks to its high adaptability to environmental conditions. The increasing incidence of antibiotic-resistant strains has created a need for alternative methods to increase the chance of recovery in infected patients. Various nanomaterials have the potential to be used for this purpose. Therefore, we aimed to study the physiological response of P. aeruginosa PAO1 to titanium dioxide/silica nanotubes. The results suggest that UV light-irradiated nanomaterial triggers strong agglomeration in the studied bacteria that was confirmed by microscopy, spectrophotometry, and flow cytometry. The effect was diminished when the nanomaterial was applied without initial irradiation, with UV light indicating that the creation of reactive oxygen species could play a role in this phenomenon. The nanocomposite also affected biofilm formation ability. Even though the biomass of biofilms was comparable, the viability of cells in biofilms was upregulated in 48-hour biofilms. Furthermore, from six selected genes, the mexA coding efflux pump was upregulated, which could be associated with an interaction with TiO2. The results show that titanium dioxide/silica nanotubes may alter the physiological and metabolic functions of P. aeruginosa PAO1.
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Affiliation(s)
- Adrian Augustyniak
- Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology, Szczecin, Piastów Avenue 42, 71-065 Szczecin, Poland;
- Chair of Building Materials and Construction Chemistry, Technische Universität Berlin, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
- Department of Microbiology and Biotechnology, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology, Szczecin, Piastów Avenue 45, 70-311 Szczecin, Poland;
| | - Krzysztof Cendrowski
- Department of Nanomaterials Physicochemistry, West Pomeranian University of Technology, Szczecin, Piastów Avenue 45, 70-311 Szczecin, Poland; (K.C.); (M.T.); (E.M.)
| | - Bartłomiej Grygorcewicz
- Chair of Microbiology, Immunology and Laboratory Medicine, Department of Laboratory Medicine, Pomeranian Medical University in Szczecin, Powstańców Wielkopolskich Avenue 72, 70-111 Szczecin, Poland
| | - Joanna Jabłońska
- Department of Chemical and Process Engineering, Faculty of Chemical Technology and Engineering, West Pomeranian University of Technology, Szczecin, Piastów Avenue 42, 71-065 Szczecin, Poland;
- Department of Microbiology and Biotechnology, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology, Szczecin, Piastów Avenue 45, 70-311 Szczecin, Poland;
| | - Paweł Nawrotek
- Department of Microbiology and Biotechnology, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology, Szczecin, Piastów Avenue 45, 70-311 Szczecin, Poland;
| | - Martyna Trukawka
- Department of Nanomaterials Physicochemistry, West Pomeranian University of Technology, Szczecin, Piastów Avenue 45, 70-311 Szczecin, Poland; (K.C.); (M.T.); (E.M.)
| | - Ewa Mijowska
- Department of Nanomaterials Physicochemistry, West Pomeranian University of Technology, Szczecin, Piastów Avenue 45, 70-311 Szczecin, Poland; (K.C.); (M.T.); (E.M.)
| | - Magdalena Popowska
- Department of Bacterial Physiology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Miecznikowa Street 1, 02-096 Warsaw, Poland;
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Adewunmi Y, Namjilsuren S, Walker WD, Amato DN, Amato DV, Mavrodi OV, Patton DL, Mavrodi DV. Antimicrobial Activity of, and Cellular Pathways Targeted by, p-Anisaldehyde and Epigallocatechin Gallate in the Opportunistic Human Pathogen Pseudomonas aeruginosa. Appl Environ Microbiol 2020; 86:e02482-19. [PMID: 31811038 PMCID: PMC6997733 DOI: 10.1128/aem.02482-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 12/04/2019] [Indexed: 12/13/2022] Open
Abstract
Plant-derived aldehydes are constituents of essential oils that possess broad-spectrum antimicrobial activity and kill microorganisms without promoting resistance. In our previous study, we incorporated p-anisaldehyde from star anise into a polymer network called proantimicrobial networks via degradable acetals (PANDAs) and used it as a novel drug delivery platform. PANDAs released p-anisaldehyde upon a change in pH and humidity and controlled the growth of the multidrug-resistant pathogen Pseudomonas aeruginosa PAO1. In this study, we identified the cellular pathways targeted by p-anisaldehyde by generating 10,000 transposon mutants of PAO1 and screened them for hypersensitivity to p-anisaldehyde. To improve the antimicrobial efficacy of p-anisaldehyde, we combined it with epigallocatechin gallate (EGCG), a polyphenol from green tea, and demonstrated that it acts synergistically with p-anisaldehyde in killing P. aeruginosa We then used transcriptome sequencing to profile the responses of P. aeruginosa to p-anisaldehyde, EGCG, and their combination. The exposure to p-anisaldehyde altered the expression of genes involved in modification of the cell envelope, membrane transport, drug efflux, energy metabolism, molybdenum cofactor biosynthesis, and the stress response. We also demonstrate that the addition of EGCG reversed many p-anisaldehyde-coping effects and induced oxidative stress. Our results provide insight into the antimicrobial activity of p-anisaldehyde and its interactions with EGCG and may aid in the rational identification of new synergistically acting combinations of plant metabolites. Our study also confirms the utility of the thiol-ene polymer platform for the sustained and effective delivery of hydrophobic and volatile antimicrobial compounds.IMPORTANCE Essential oils (EOs) are plant-derived products that have long been exploited for their antimicrobial activities in medicine, agriculture, and food preservation. EOs represent a promising alternative to conventional antibiotics due to their broad-range antimicrobial activity, low toxicity to human commensal bacteria, and capacity to kill microorganisms without promoting resistance. Despite the progress in the understanding of the biological activity of EOs, our understanding of many aspects of their mode of action remains inconclusive. The overarching aim of this work was to address these gaps by studying the molecular interactions between an antimicrobial plant aldehyde and the opportunistic human pathogen Pseudomonas aeruginosa The results of this study identify the microbial genes and associated pathways involved in the response to antimicrobial phytoaldehydes and provide insights into the molecular mechanisms governing the synergistic effects of individual constituents within essential oils.
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Affiliation(s)
- Yetunde Adewunmi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Sanchirmaa Namjilsuren
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - William D Walker
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Dahlia N Amato
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Douglas V Amato
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Olga V Mavrodi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
- South MS Branch Experiment Station, Mississippi State University, Poplarville, Mississippi, USA
| | - Derek L Patton
- School of Polymer Science and Engineering, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
| | - Dmitri V Mavrodi
- School of Biological, Environmental, and Earth Sciences, The University of Southern Mississippi, Hattiesburg, Mississippi, USA
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14
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Guo W, Sun C, Jiang G, Xin Y. Recent Developments of Nanoparticles in the Treatment of Photodynamic Therapy for Cervical Cancer. Anticancer Agents Med Chem 2019; 19:1809-1819. [PMID: 30973114 DOI: 10.2174/1871520619666190411121953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/08/2019] [Accepted: 03/01/2019] [Indexed: 01/06/2023]
Abstract
Photodynamic therapy (PDT) is a photoactivation or photosensitization process, wherein the photosensitizer
(PS) is activated under appropriate wavelengths. Conventional antitumor therapy for cervical cancer
includes surgery, radiotherapy, and chemotherapy. However, these techniques are accompanied by some evident
shortcomings. PDT is considered an emerging minimally invasive treatment for cervical cancer. In recent years,
new PSs have been synthesized because of the long absorption wavelength, good solubility, and high tumor
targeting ability. Studies also showed that the synergistic combination of nanomaterials with PSs resulted in
considerable benefits compared with the use of small-molecule PSs alone. The compounds can act both as a
drug delivery system and PS and enhance the photodynamic effect. This review summarizes the application of
some newly synthesized PSs and PS-combined nanoparticles in cervical cancer treatment to enhance the efficiency
of PDT. The mechanism and influencing factors of PDT are further elaborated.
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Affiliation(s)
- Wenwen Guo
- Department of Radiation, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China
| | - Chao Sun
- Department of Dermatology, Xinyi People's Hospital, Xuzhou 221002, China
| | - Guan Jiang
- Department of Dermatology, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China
| | - Yong Xin
- Department of Radiation, Affiliated Hospital of Xuzhou Medical University, Xuzhou 221002, China
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15
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Acinetobacter baumannii OxyR Regulates the Transcriptional Response to Hydrogen Peroxide. Infect Immun 2018; 87:IAI.00413-18. [PMID: 30297527 DOI: 10.1128/iai.00413-18] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/03/2018] [Indexed: 12/21/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic pathogen that causes diverse infections, including pneumonia, bacteremia, and wound infections. Due to multiple intrinsic and acquired antimicrobial-resistance mechanisms, A. baumannii isolates are commonly multidrug resistant, and infections are notoriously difficult to treat. The World Health Organization recently highlighted carbapenem-resistant A. baumannii as a "critical priority" for the development of new antimicrobials because of the risk to human health posed by this organism. Therefore, it is important to discover the mechanisms used by A. baumannii to survive stresses encountered during infection in order to identify new drug targets. In this study, by use of in vivo imaging, we identified hydrogen peroxide (H2O2) as a stressor produced in the lung during A. baumannii infection and defined OxyR as a transcriptional regulator of the H2O2 stress response. Upon exposure to H2O2, A. baumannii differentially transcribes several hundred genes. However, the transcriptional upregulation of genes predicted to detoxify hydrogen peroxide is abolished in an A. baumannii strain in which the transcriptional regulator oxyR is genetically inactivated. Moreover, inactivation of oxyR in both antimicrobial-susceptible and multidrug-resistant A. baumannii strains impairs growth in the presence of H2O2 OxyR is a direct regulator of katE and ahpF1, which encode the major H2O2-degrading enzymes in A. baumannii, as confirmed through measurement of promoter binding by recombinant OxyR in electromobility shift assays. Finally, an oxyR mutant is less fit than wild-type A. baumannii during infection of the murine lung. This work reveals a mechanism used by this important human pathogen to survive H2O2 stress encountered during infection.
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Chen W, Wang B, Gruber JD, Zhang YM, Davies C. Acyl Carrier Protein 3 Is Involved in Oxidative Stress Response in Pseudomonas aeruginosa. Front Microbiol 2018; 9:2244. [PMID: 30294316 PMCID: PMC6158461 DOI: 10.3389/fmicb.2018.02244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/03/2018] [Indexed: 12/01/2022] Open
Abstract
The human opportunistic pathogen Pseudomonas aeruginosa expresses three acyl carrier proteins (ACPs): AcpP, Acp1, and Acp3. The function of AcpP in membrane fatty acid synthesis (FAS) was confirmed recently, but the physiological roles of Acp1 and Acp3 remain unclear. To address this, we investigated the physiological role of Acp3 in P. aeruginosa. We found that expression of Acp3 dramatically increases in the log phase of cell growth and that its transcription is under the control of the QS regulators LasR and RhlR. Deletion of acp3 from P. aeruginosa strain PAO1 results in thicker biofilm formation, increased resistance of the strain to hydrogen peroxide, and higher persistence in a mouse infection model. Tandem affinity purification (TAP) experiments revealed several novel protein-binding partners of Acp3, including KatA, the major catalase in P. aeruginosa. Acp3 was found to repress the catalase activity of KatA and, consistent with inhibition by Acp3, less reactive oxygen species are present in the acp3 deletion strain. Overall, our study reveals that Acp3 has a distinct function from that of the canonical AcpP and may be involved in the oxidative stress response.
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Affiliation(s)
- Wei Chen
- Clinical Research Center, The Second Affiliated Hospital of the Southeast University, Nanjing, China.,Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Bo Wang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jordon D Gruber
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Yong-Mei Zhang
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, United States
| | - Christopher Davies
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, United States
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17
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Polymorphonuclear Leukocytes or Hydrogen Peroxide Enhance Biofilm Development of Mucoid Pseudomonas aeruginosa. Mediators Inflamm 2018; 2018:8151362. [PMID: 30116152 PMCID: PMC6079396 DOI: 10.1155/2018/8151362] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/13/2018] [Accepted: 04/16/2018] [Indexed: 01/05/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogenic bacterium involved in many human infections, including pneumonia, diabetic foot ulcers, and ventilator-associated pneumonia. P. aeruginosa cells usually undergo mucoid conversion during chronic lung infection in patients with cystic fibrosis (CF) and resist destruction by polymorphonuclear leukocytes (PMNs), which release free oxygen radicals (ROS), such as H2O2. PMNs are the main leucocytes in the CF sputum of patients who are infected with P. aeruginosa, which usually forms biofilms. Here, we report that PMNs or H2O2 can promote biofilm formation by mucoid P. aeruginosa FRD1 with the use of the hanging-peg method. The mucoid strain infecting CF patients overproduces alginate. In this study, PMNs and H2O2 promoted alginate production, and biofilms treated with PMNs or H2O2 exhibited higher expression of alginate genes. Additionally, PMNs increased the activity of GDP-mannose dehydrogenase, which is the key enzyme in alginate biosynthesis. Our results demonstrate that PMNs or H2O2 can enhance mucoid P. aeruginosa biofilms.
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18
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Aharoni N, Mamane H, Biran D, Lakretz A, Ron EZ. Gene expression in Pseudomonas aeruginosa exposed to hydroxyl-radicals. CHEMOSPHERE 2018; 199:243-250. [PMID: 29448190 DOI: 10.1016/j.chemosphere.2018.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/23/2017] [Accepted: 02/03/2018] [Indexed: 06/08/2023]
Abstract
Recent studies have shown the efficiency of hydroxyl radicals generated via ultraviolet (UV)-based advanced oxidation processes (AOPs) combined with hydrogen peroxide (UV/H2O2) as a treatment process in water. The effects of AOP treatments on bacterial gene expression was examined using Pseudomonas aeruginosa strain PAO1 as a model-organism bacterium. Many bacterial genes are not expressed all the time, but their expression is regulated. The regulation is at the beginning of the gene, in a genetic region called "promoter" and affects the level of transcription (synthesis of messenger RNA) and translation (synthesis of protein). The level of expression of the regulated genes can change as a function of environmental conditions, and they can be expressed more (induced, upregulated) or less (downregulated). Exposure of strain PAO1 to UV/H2O2 treatment resulted in a major change in gene expression, including elevated expression of several genes. One interesting gene is PA3237, which was significantly upregulated under UV/H2O2 as compared to UV or H2O2 treatments alone. The induction of this gene is probably due to formation of radicals, as it is abolished in the presence of the radical scavenger tert-butanol (TBA) and is seen even when the bacteria are added after the treatment (post-treatment exposure). Upregulation of the PA3237 promoter could also be detected using a reporter gene, suggesting the use of such genetic constructs to develop biosensors for monitoring AOPs in water-treatment plants. Currently biosensors for AOPs do not exist, consequently impairing the ability to monitor these processes on-line according to radical exposure in natural waters.
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Affiliation(s)
- Noa Aharoni
- Porter School of Environmental Studies, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hadas Mamane
- School of Mechanical Engineering, Environmental Engineering Program, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Dvora Biran
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anat Lakretz
- School of Mechanical Engineering, Environmental Engineering Program, Tel Aviv University, Tel Aviv 69978, Israel; Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Eliora Z Ron
- Department of Molecular Microbiology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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19
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Strempel N, Nusser M, Neidig A, Brenner-Weiss G, Overhage J. The Oxidative Stress Agent Hypochlorite Stimulates c-di-GMP Synthesis and Biofilm Formation in Pseudomonas aeruginosa. Front Microbiol 2017; 8:2311. [PMID: 29213262 PMCID: PMC5702645 DOI: 10.3389/fmicb.2017.02311] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/08/2017] [Indexed: 01/25/2023] Open
Abstract
The opportunistic human pathogen Pseudomonas aeruginosa is able to survive under a variety of often harmful environmental conditions due to a multitude of intrinsic and adaptive resistance mechanisms, including biofilm formation as one important survival strategy. Here, we investigated the adaptation of P. aeruginosa PAO1 to hypochlorite (HClO), a phagocyte-derived host defense compound and frequently used disinfectant. In static biofilm assays, we observed a significant enhancement in initial cell attachment in the presence of sublethal HClO concentrations. Subsequent LC-MS analyses revealed a strong increase in cyclic-di-GMP (c-di-GMP) levels suggesting a key role of this second messenger in HClO-induced biofilm development. Using DNA microarrays, we identified a 26-fold upregulation of ORF PA3177 coding for a putative diguanylate cyclase (DGC), which catalyzes the synthesis of the second messenger c-di-GMP – an important regulator of bacterial motility, sessility and persistence. This DGC PA3177 was further characterized in more detail demonstrating its impact on P. aeruginosa motility and biofilm formation. In addition, cell culture assays attested a role for PA3177 in the response of P. aeruginosa to human phagocytes. Using a subset of different mutants, we were able to show that both Pel and Psl exopolysaccharides are effectors in the PA3177-dependent c-di-GMP network.
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Affiliation(s)
- Nikola Strempel
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Michael Nusser
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Anke Neidig
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Gerald Brenner-Weiss
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Joerg Overhage
- Institute of Functional Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Department of Health Sciences, Carleton University, Ottawa, ON, Canada
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20
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Okon E, Dethlefsen S, Pelnikevich A, Barneveld AV, Munder A, Tümmler B. Key role of an ADP - ribose - dependent transcriptional regulator of NAD metabolism for fitness and virulence of Pseudomonas aeruginosa. Int J Med Microbiol 2016; 307:83-94. [PMID: 27865623 DOI: 10.1016/j.ijmm.2016.09.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 08/31/2016] [Accepted: 09/25/2016] [Indexed: 10/20/2022] Open
Abstract
NAD is an essential co-factor of redox reactions and metabolic conversions of NAD-dependent enzymes. NAD biosynthesis in the opportunistic pathogen Pseudomonas aeruginosa has yet not been experimentally explored. The in silico search for orthologs in the P. aeruginosa PAO1 genome identified the operon pncA - pncB1-nadE (PA4918-PA4920) to encode the nicotinamidase, nicotinate phosporibosyltransferase and Nad synthase of salvage pathway I. The functional role of the preceding genes PA4917 and PA4916 was resolved by the characterization of recombinant protein. PA4917 turned out to encode the nicotinate mononucleotide adenylyltransferase NadD2 and PA4916 was determined to encode the transcriptional repressor NrtR that binds to an intergenic sequence between nadD2 and pncA. Complex formation between the catalytically inactive Nudix protein NrtR and its DNA binding site was suppressed by the antirepressor ADP-ribose. NrtR plasposon mutagenesis abrogated virulence of P. aeruginosa TBCF10839 in a murine acute airway infection model and constrained its metabolite profile. When grown together with other isogenic plasposon mutants, the nrtR knock-out was most compromised in competitive fitness to persist in nutrient-rich medium in vitro or murine airways in vivo. This example demonstrates how tightly metabolism and virulence can be intertwined by key elements of metabolic control.
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Affiliation(s)
- Elza Okon
- Klinische Forschergruppe, OE 6710, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Sarah Dethlefsen
- Klinische Forschergruppe, OE 6710, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Anna Pelnikevich
- Klinische Forschergruppe, OE 6710, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Andrea van Barneveld
- Klinische Forschergruppe, OE 6710, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany
| | - Antje Munder
- Klinische Forschergruppe, OE 6710, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany
| | - Burkhard Tümmler
- Klinische Forschergruppe, OE 6710, Klinik für Pädiatrische Pneumologie, Allergologie und Neonatologie, Medizinische Hochschule Hannover, Hannover, Germany; Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research, Hannover, Germany.
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21
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Topaloglu N, Guney M, Aysan N, Gulsoy M, Yuksel S. The role of reactive oxygen species in the antibacterial photodynamic treatment: photoinactivation vs
proliferation. Lett Appl Microbiol 2016; 62:230-6. [DOI: 10.1111/lam.12538] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/27/2015] [Accepted: 12/08/2015] [Indexed: 11/30/2022]
Affiliation(s)
- N. Topaloglu
- Institute of Biomedical Engineering; Bogazici University; Istanbul Turkey
| | - M. Guney
- Institute of Biomedical Engineering; Bogazici University; Istanbul Turkey
- Department of Biomedical Engineering; Istanbul Medeniyet University; Istanbul Turkey
| | - N. Aysan
- Institute of Biomedical Engineering; Bogazici University; Istanbul Turkey
| | - M. Gulsoy
- Institute of Biomedical Engineering; Bogazici University; Istanbul Turkey
| | - S. Yuksel
- Molecular Biology and Genetics Department; Bogazici University; Istanbul Turkey
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22
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Contribution of stress responses to antibiotic tolerance in Pseudomonas aeruginosa biofilms. Antimicrob Agents Chemother 2015; 59:3838-47. [PMID: 25870065 DOI: 10.1128/aac.00433-15] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/07/2015] [Indexed: 11/20/2022] Open
Abstract
Enhanced tolerance of biofilm-associated bacteria to antibiotic treatments is likely due to a combination of factors, including changes in cell physiology as bacteria adapt to biofilm growth and the inherent physiological heterogeneity of biofilm bacteria. In this study, a transcriptomics approach was used to identify genes differentially expressed during biofilm growth of Pseudomonas aeruginosa. These genes were tested for statistically significant overlap, with independently compiled gene lists corresponding to stress responses and other putative antibiotic-protective mechanisms. Among the gene groups tested were those associated with biofilm response to tobramycin or ciprofloxacin, drug efflux pumps, acyl homoserine lactone quorum sensing, osmotic shock, heat shock, hypoxia stress, and stationary-phase growth. Regulons associated with Anr-mediated hypoxia stress, RpoS-regulated stationary-phase growth, and osmotic stress were significantly enriched in the set of genes induced in the biofilm. Mutant strains deficient in rpoS, relA and spoT, or anr were cultured in biofilms and challenged with ciprofloxacin and tobramycin. When challenged with ciprofloxacin, the mutant strain biofilms had 2.4- to 2.9-log reductions in viable cells compared to a 0.9-log reduction of the wild-type strain. Interestingly, none of the mutants exhibited a statistically significant alteration in tobramycin susceptibility compared to that with the wild-type biofilm. These results are consistent with a model in which multiple genes controlled by overlapping starvation or stress responses contribute to the protection of a P. aeruginosa biofilm from ciprofloxacin. A distinct and as yet undiscovered mechanism protects the biofilm bacteria from tobramycin.
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23
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 920] [Impact Index Per Article: 102.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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Green LK, La Flamme AC, Ackerley DF. Pseudomonas aeruginosa MdaB and WrbA are water-soluble two-electron quinone oxidoreductases with the potential to defend against oxidative stress. J Microbiol 2014; 52:771-7. [DOI: 10.1007/s12275-014-4208-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 06/25/2014] [Accepted: 07/02/2014] [Indexed: 10/25/2022]
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25
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Llamas MA, Imperi F, Visca P, Lamont IL. Cell-surface signaling inPseudomonas: stress responses, iron transport, and pathogenicity. FEMS Microbiol Rev 2014; 38:569-97. [DOI: 10.1111/1574-6976.12078] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 05/20/2014] [Accepted: 05/27/2014] [Indexed: 01/06/2023] Open
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26
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Steady-state hydrogen peroxide induces glycolysis in Staphylococcus aureus and Pseudomonas aeruginosa. J Bacteriol 2014; 196:2499-513. [PMID: 24769698 DOI: 10.1128/jb.01538-14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from human pathogens Staphylococcus aureus and Pseudomonas aeruginosa can be readily inhibited by reactive oxygen species (ROS)-mediated direct oxidation of their catalytic active cysteines. Because of the rapid degradation of H2O2 by bacterial catalase, only steady-state but not one-dose treatment with H2O2 rapidly induces glycolysis and the pentose phosphate pathway (PPP). We conducted transcriptome sequencing (RNA-seq) analyses to globally profile the bacterial transcriptomes in response to a steady level of H2O2, which revealed profound transcriptional changes, including the induced expression of glycolytic genes in both bacteria. Our results revealed that the inactivation of GAPDH by H2O2 induces metabolic levels of glycolysis and the PPP; the elevated levels of fructose 1,6-biphosphate (FBP) and 2-keto-3-deoxy-6-phosphogluconate (KDPG) lead to dissociation of their corresponding glycolytic repressors (GapR and HexR, respectively) from their cognate promoters, thus resulting in derepression of the glycolytic genes to overcome H2O2-stalled glycolysis in S. aureus and P. aeruginosa, respectively. Both GapR and HexR may directly sense oxidative stresses, such as menadione.
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Donati AJ, Lee HI, Leveau JHJ, Chang WS. Effects of indole-3-acetic acid on the transcriptional activities and stress tolerance of Bradyrhizobium japonicum. PLoS One 2013; 8:e76559. [PMID: 24098533 PMCID: PMC3788728 DOI: 10.1371/journal.pone.0076559] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/28/2013] [Indexed: 11/18/2022] Open
Abstract
A genome-wide transcriptional profile of Bradyrhizobium japonicum, the nitrogen-fixing endosymbiont of the soybean plant, revealed differential expression of approximately 15% of the genome after a 1 mM treatment with the phytohormone indole-3-acetic acid (IAA). A total of 1,323 genes were differentially expressed (619 up-regulated and 704 down-regulated) at a two-fold cut off with q value ≤ 0.05. General stress response genes were induced, such as those involved in response to heat, cold, oxidative, osmotic, and desiccation stresses and in exopolysaccharide (EPS) biosynthesis. This suggests that IAA is effective in activating a generalized stress response in B. japonicum. The transcriptional data were corroborated by the finding that stress tolerance of B. japonicum in cell viability assays was enhanced when pre-treated with 1 mM IAA compared to controls. The IAA treatment also stimulated biofilm formation and EPS production by B. japonicum, especially acidic sugar components in the total EPS. The IAA pre-treatment did not influence the nodulation ability of B. japonicum. The data provide a comprehensive overview of the potential transcriptional responses of the symbiotic bacterium when exposed to the ubiquitous hormone of its plant host.
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Affiliation(s)
- Andrew J. Donati
- Department of Biology, University of Texas, Arlington, Texas, United States of America
| | - Hae-In Lee
- Department of Biology, University of Texas, Arlington, Texas, United States of America
| | - Johan H. J. Leveau
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Woo-Suk Chang
- Department of Biology, University of Texas, Arlington, Texas, United States of America
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28
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Deng X, Weerapana E, Ulanovskaya O, Sun F, Liang H, Ji Q, Ye Y, Fu Y, Zhou L, Li J, Zhang H, Wang C, Alvarez S, Hicks LM, Lan L, Wu M, Cravatt BF, He C. Proteome-wide quantification and characterization of oxidation-sensitive cysteines in pathogenic bacteria. Cell Host Microbe 2013; 13:358-70. [PMID: 23498960 DOI: 10.1016/j.chom.2013.02.004] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Revised: 12/03/2012] [Accepted: 02/11/2013] [Indexed: 12/29/2022]
Abstract
Thiol-group oxidation of active and allosteric cysteines is a widespread regulatory posttranslational protein modification. Pathogenic bacteria, including Pseudomonas aeruginosa and Staphylococcus aureus, use regulatory cysteine oxidation to respond to and overcome reactive oxygen species (ROS) encountered in the host environment. To obtain a proteome-wide view of oxidation-sensitive cysteines in these two pathogens, we employed a competitive activity-based protein profiling approach to globally quantify hydrogen peroxide (H2O2) reactivity with cysteines across bacterial proteomes. We identified ∼200 proteins containing H2O2-sensitive cysteines, including metabolic enzymes, transcription factors, and uncharacterized proteins. Additional biochemical and genetic studies identified an oxidation-responsive cysteine in the master quorum-sensing regulator LasR and redox-regulated activities for acetaldehyde dehydrogenase ExaC, arginine deiminase ArcA, and glyceraldehyde 3-phosphate dehydrogenase. Taken together, our data indicate that pathogenic bacteria exhibit a complex, multilayered response to ROS that includes the rapid adaption of metabolic pathways to oxidative-stress challenge.
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Affiliation(s)
- Xin Deng
- Department of Chemistry and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA
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Cierniak P, Jübner M, Müller S, Bender K. Insights into mechanisms and proteomic characterisation of Pseudomonas aeruginosa adaptation to a novel antimicrobial substance. PLoS One 2013; 8:e66862. [PMID: 23869205 PMCID: PMC3711899 DOI: 10.1371/journal.pone.0066862] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Accepted: 05/11/2013] [Indexed: 11/22/2022] Open
Abstract
Antibiotic resistance has been reported since the introduction of synthetic antibiotics. Bacteria, such as one of the most common nosocomial pathogens P. aeruginosa, adapt quickly to changing environmental conditions, due to their short generation time. Thus microevolutional changes can be monitored in situ. In this study, the microevolutional process of Pseudomonas aeruginosa PAO1 resistance against a recently developed novel antibacterial zinc Schiff-base (ZSB) was investigated at the proteome level. After extended exposure to ZSB the passaged strain differed in tolerance against ZSB, with the adapted P. aeruginosa PAO1 exhibiting 1.6 times higher minimal inhibitory concentration. Using Two-dimensional Difference Gel Electrophoresis, the changes in the proteome of ZSB adapted P. aeruginosa PAO1 were examined by comparison with the non-adapted P. aeruginosa PAO1. The proteome of the adapted P. aeruginosa PAO1 strain differed significantly from the non-adapted in the abundance of two proteins when both strains were grown under stressing conditions. One protein could be identified as the outer membrane protein D that plays a role in uptake of basic amino acids as well as in carbapeneme resistance. The second protein has been identified as alkyl peroxide reductase subunit F. Our data indicated a slight increase in abundance of alkyl peroxide reductase F (AhpF) in the case of ZSB passaged P. aeruginosa PAO1. Higher abundance of Ahp has been discussed in the literature as a promoter of accelerated detoxification of benzene derivatives. The observed up-regulated AhpF thus appears to be connected to an increased tolerance against ZSB. Changes in the abundance of proteins connected to oxidative stress were also found after short-time exposure of P. aeruginosa PAO1 to the ZSB. Furthermore, adapted P. aeruginosa PAO1 showed increased tolerance against hydrogen peroxide and, in addition, showed accelerated degradation of ZSB, as determined by HPLC measurements.
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Affiliation(s)
- Peter Cierniak
- Institute of Legal Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Martin Jübner
- Institute of Legal Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Stefan Müller
- Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Katja Bender
- Institute of Legal Medicine, Medical Faculty, University of Cologne, Cologne, Germany
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30
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Reen FJ, Haynes JM, Mooij MJ, O'Gara F. A non-classical LysR-type transcriptional regulator PA2206 is required for an effective oxidative stress response in Pseudomonas aeruginosa. PLoS One 2013; 8:e54479. [PMID: 23382903 PMCID: PMC3557286 DOI: 10.1371/journal.pone.0054479] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 12/12/2012] [Indexed: 01/13/2023] Open
Abstract
LysR-type transcriptional regulators (LTTRs) are emerging as key circuit components in regulating microbial stress responses and are implicated in modulating oxidative stress in the human opportunistic pathogen Pseudomonas aeruginosa. The oxidative stress response encapsulates several strategies to overcome the deleterious effects of reactive oxygen species. However, many of the regulatory components and associated molecular mechanisms underpinning this key adaptive response remain to be characterised. Comparative analysis of publically available transcriptomic datasets led to the identification of a novel LTTR, PA2206, whose expression was altered in response to a range of host signals in addition to oxidative stress. PA2206 was found to be required for tolerance to H2O2in vitro and lethality in vivo in the Zebrafish embryo model of infection. Transcriptomic analysis in the presence of H2O2 showed that PA2206 altered the expression of 58 genes, including a large repertoire of oxidative stress and iron responsive genes, independent of the master regulator of oxidative stress, OxyR. Contrary to the classic mechanism of LysR regulation, PA2206 did not autoregulate its own expression and did not influence expression of adjacent or divergently transcribed genes. The PA2214-15 operon was identified as a direct target of PA2206 with truncated promoter fragments revealing binding to the 5′-ATTGCCTGGGGTTAT-3′ LysR box adjacent to the predicted −35 region. PA2206 also interacted with the pvdS promoter suggesting a global dimension to the PA2206 regulon, and suggests PA2206 is an important regulatory component of P. aeruginosa adaptation during oxidative stress.
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Affiliation(s)
| | | | | | - Fergal O'Gara
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Cork, Ireland
- * E-mail:
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31
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Wang X, Li M, Liu L, Mou R, Zhang X, Bai Y, Xu H, Qiao M. DsbM, a novel disulfide oxidoreductase affects aminoglycoside resistance in Pseudomonas aeruginosa by OxyR-regulated response. J Microbiol 2012; 50:932-8. [PMID: 23274979 DOI: 10.1007/s12275-012-2177-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/04/2012] [Indexed: 11/30/2022]
Abstract
A Pseudomonas aeruginosa mutant strain M122 was isolated from a Mu transposon insertion mutant library. In our prophase research, we have found that PA0058, a novel gene encodes a 234-residue conserved protein, was disrupted in the M122 mutant. In this study, the bacteriostatic experiment in vitro indicates that M122 has abnormally high aminoglycoside resistance. We expressed PA0058 in E. coli and found that PA0058 oxidizes and reduces disulfide. This biochemical characterization suggests that PA0058 is a novel disulfide oxidoreductase. Hence, the protein was designated as DsbM. Microarray analysis of the M122 mutant showed its unusual phenotype might be related to the bacterial antioxidant defense system mediated by the oxyR regulon. Meanwhile, we detected -SH content in the periplasm of M122 and wild strain and found a lower -SH/S-S ratio in M122. Therefore, we consider that the loss of dsbM function decreased the -SH/S-S ratio, which then prolongs the OxyR-regulated response, thereby conferring high aminoglycoside resistance to the M122 mutant strain. Our findings have important implications for understanding the mechanisms underlying aminoglycoside resistance in P. aeruginosa.
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Affiliation(s)
- Xuehan Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, PR China
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Tribelli PM, Nikel PI, Oppezzo OJ, López NI. Anr, the anaerobic global regulator, modulates the redox state and oxidative stress resistance in Pseudomonas extremaustralis. MICROBIOLOGY-SGM 2012; 159:259-268. [PMID: 23223440 DOI: 10.1099/mic.0.061085-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The role of Anr in oxidative stress resistance was investigated in Pseudomonas extremaustralis, a polyhydroxybutyrate-producing Antarctic bacterium. The absence of Anr caused increased sensitivity to hydrogen peroxide under low oxygen tension. This phenomenon was associated with a decrease in the redox ratio, higher oxygen consumption and higher reactive oxygen species production. Physiological responses of the mutant to the oxidized state included an increase in NADP(H) content, catalase activity and exopolysaccharide production. The wild-type strain showed a sharp decrease in the reduced thiol pool when exposed to hydrogen peroxide, not observed in the mutant strain. In silico analysis of the genome sequence of P. extremaustralis revealed putative Anr binding sites upstream from genes related to oxidative stress. Genes encoding several chaperones and cold shock proteins, a glutathione synthase, a sulfate transporter and a thiol peroxidase were identified as potential targets for Anr regulation. Our results suggest a novel role for Anr in oxidative stress resistance and in redox balance maintenance under conditions of restricted oxygen supply.
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Affiliation(s)
- Paula M Tribelli
- Dpto de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Pablo I Nikel
- Instituto de Investigaciones Biotecnológicas 'Dr. Rodolfo A. Ugalde', IQUIBICEN-CONICET, Universidad Nacional de San Martín, Buenos Aires, Argentina.,Dpto de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Oscar J Oppezzo
- Departamento de Radiobiología, Comisión Nacional de Energía Atómica, Buenos Aires, Argentina
| | - Nancy I López
- Dpto de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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33
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Liu X, Li J, Wang Y, Li T, Zhao J, Zhang C. Green tea polyphenols function as prooxidants to inhibit Pseudomonas aeruginosa and induce the expression of oxidative stress-related genes. Folia Microbiol (Praha) 2012; 58:211-7. [PMID: 23054687 DOI: 10.1007/s12223-012-0198-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 09/19/2012] [Indexed: 10/27/2022]
Abstract
Green tea polyphenols (GTP) are widely believed to function as antioxidants and antimicrobial agents. Here we observed that GTP and epigallocatechin gallate, the most abundant catechin in GTP, could also function as prooxidants and produce hydrogen peroxide (H2O2) to inhibit the growth of Pseudomonas aeruginosa. pH value of the medium was the key factor that affected prooxidant versus antioxidant property of GTP. Under weakly acidic conditions (pH 5.5-6.5), GTP showed antioxidant activity by eliminating H2O2; whereas, under neutral and weakly alkaline conditions (pH 7.0-8.0), GTP showed prooxidant activity and inhibited the growth of P. aeruginosa. Furthermore, we studied the effects of GTP on gene expression profiles of a few oxidative stress-related genes by quantitative real-time PCR analysis. After 10 min to 1 h of exposure under weakly alkaline condition, GTP significantly up-regulated expression levels of katB, sodM, ohr, lexA, and recN gene. These findings highlight that the pH-dependent H2O2 production by GTP contributes to the antibacterial activity and can induce oxidative stress-related responses in P. aeruginosa.
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Affiliation(s)
- Xiaoxiang Liu
- Faculty of Basic Medicine, Zhejiang Medical College, Hangzhou, Zhejiang 310053, China
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34
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Comparative analysis of temperature-dependent transcriptome of Pseudomonas aeruginosa strains from rhizosphere and human habitats. Appl Microbiol Biotechnol 2012; 96:1007-19. [PMID: 23053111 DOI: 10.1007/s00253-012-4466-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 09/19/2012] [Accepted: 09/21/2012] [Indexed: 01/13/2023]
Abstract
In this study, we investigated the effects of a change in growth temperature on the transcriptome of two strains of Pseudomonas aeruginosa. The chosen P. aeruginosa strains were M18 and PAO1, which are adapted to two different niches, rhizosphere and human, respectively. To assess the changes induced by a change in temperature, we used a newly designed microarray covering the complete genome of four P. aeruginosa strains: PAO1, M18, PA14 and LESB58, which proved informative and reliable for the transcriptome study. Using the microarray, we analysed the transcriptome profile changes of two P. aeruginosa strains of M18 and PAO1 at their originating and non-originating temperatures: 28 °C for the rhizosphere and 37 °C for the human. The transcriptome profiles showed significant temperature-dependent differences (64.8 % in M18 and 66.8 % in PAO1) compared with the genome structure (6 % in M18 and 4.1 % in PAO1). Furthermore, we found that the specific induced genes at the non-originating growth temperature of the each strain (207 genes in M18 and 229 genes in PAO1) were evidently more than those induced at the originating growth temperature (158 genes in M18 and 169 genes in PAO1). The functional analysis of several newly found specific regulated operons (such as phh, liu, hmg) in the two strains indicated possible strategies implemented to respond to the non-originating temperature. This study provides new insight into how P. aeruginosa species responds to temperature change and a microarray platform covering the complete genomes of four widely studied P. aeruginosa strains.
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35
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Brul S, Bassett J, Cook P, Kathariou S, McClure P, Jasti P, Betts R. ‘Omics’ technologies in quantitative microbial risk assessment. Trends Food Sci Technol 2012. [DOI: 10.1016/j.tifs.2012.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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36
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Klockgether J, Miethke N, Kubesch P, Bohn YS, Brockhausen I, Cramer N, Eberl L, Greipel J, Herrmann C, Herrmann S, Horatzek S, Lingner M, Luciano L, Salunkhe P, Schomburg D, Wehsling M, Wiehlmann L, Davenport CF, Tümmler B. Intraclonal diversity of the Pseudomonas aeruginosa cystic fibrosis airway isolates TBCF10839 and TBCF121838: distinct signatures of transcriptome, proteome, metabolome, adherence and pathogenicity despite an almost identical genome sequence. Environ Microbiol 2012; 15:191-210. [PMID: 22882573 DOI: 10.1111/j.1462-2920.2012.02842.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microevolution of closely related Pseudomonas aeruginosa was compared in the clone TB strains TBCF10839 and TBCF121838 which had been isolated from two unrelated individuals with cystic fibrosis who had acquired clone TB during a local outbreak. Compared with the strain PAO1 reference sequence the two clone TB genomes shared 23 155 nucleotide exchanges, 32 out-of-frame indels in the coding region and another repertoire of replacement and genomic islands such as PAGI-1, PAGI-2, PAGI-5, LESGI-1 and LES-prophage 4. Only TBCF121838 carried a genomic island known from Ralstonia pickettii. Six of the seven strain-specific sequence variations in the core genome were detected in genes affecting motility, biofilm formation or virulence, i.e. non-synonymous nucleotide substitutions in mexS, PA3729, PA5017, mifR, a frameshift mutation in pilF (TBCF121838) and an intragenic deletion in pilQ (TBCF10839). Despite their almost identical genome sequence the two strains differed strongly from each other in transcriptome and metabolome profiles, mucin adherence and phagocytosis assays. TBCF121838 was susceptible to killing by neutrophils, but TBCF10839 could grow in leucocytes. Microevolution in P. aeruginosa apparently can generate novel complex traits by few or even single mutations provided that predisposing mutational events had occurred before in the clonal lineage.
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Affiliation(s)
- Jens Klockgether
- Klinische Forschergruppe, Zentrum Biochemie und Zentrum Kinder- und Jugendmedizin, OE 6710, D-30625 Hannover, Germany.
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37
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McKenzie RME, Johnson NA, Aruni W, Dou Y, Masinde G, Fletcher HM. Differential response of Porphyromonas gingivalis to varying levels and duration of hydrogen peroxide-induced oxidative stress. MICROBIOLOGY-SGM 2012; 158:2465-2479. [PMID: 22745271 DOI: 10.1099/mic.0.056416-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Porphyromonas gingivalis, an anaerobic oral pathogen implicated in adult periodontitis, can exist in an environment of oxidative stress. To evaluate its adaptation to this environment, we have assessed the response of P. gingivalis W83 to varying levels and durations of hydrogen peroxide (H(2)O(2))-induced stress. When P. gingivalis was initially exposed to a subinhibitory concentration of H(2)O(2) (0.1 mM), an adaptive response to higher concentrations could be induced. Transcriptome analysis demonstrated that oxidative stress can modulate several functional classes of genes depending on the severity and duration of the exposure. A 10 min exposure to H(2)O(2) revealed increased expression of genes involved in DNA damage and repair, while after 15 min, genes involved in protein fate, protein folding and stabilization were upregulated. Approximately 9 and 2.8% of the P. gingivalis genome displayed altered expression in response to H(2)O(2) exposure at 10 and 15 min, respectively. Substantially more genes were upregulated (109 at 10 min; 47 at 15 min) than downregulated (76 at 10 min; 11 at 15 min) by twofold or higher in response to H(2)O(2) exposure. The majority of these modulated genes were hypothetical or of unknown function. One of those genes (pg1372) with DNA-binding properties that was upregulated during prolonged oxidative stress was inactivated by allelic exchange mutagenesis. The isogenic mutant P. gingivalis FLL363 (pg1372 : : ermF) showed increased sensitivity to H(2)O(2) compared with the parent strain. Collectively, our data indicate the adaptive ability of P. gingivalis to oxidative stress and further underscore the complex nature of its resistance strategy under those conditions.
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Affiliation(s)
- Rachelle M E McKenzie
- Center for Dental Research, School of Dentistry, Loma Linda University, Loma Linda, CA 92350, USA.,Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Neal A Johnson
- Department of Oral Diagnosis, Radiology, and Pathology, School of Dentistry, Loma Linda University, Loma Linda, CA 92350, USA.,Center for Dental Research, School of Dentistry, Loma Linda University, Loma Linda, CA 92350, USA
| | - Wilson Aruni
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Yuetan Dou
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Godfred Masinde
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
| | - Hansel M Fletcher
- Division of Microbiology and Molecular Genetics, School of Medicine, Loma Linda University, Loma Linda, CA 92350, USA
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38
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Chuanchuen R, Schweizer HP. Global transcriptional responses to triclosan exposure in Pseudomonas aeruginosa. Int J Antimicrob Agents 2012; 40:114-22. [PMID: 22704809 DOI: 10.1016/j.ijantimicag.2012.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 02/29/2012] [Accepted: 04/10/2012] [Indexed: 10/28/2022]
Abstract
Global gene transcription was assessed by microarray experiments following treatment of a triclosan-susceptible Δ(mexAB-oprM) Pseudomonas aeruginosa strain with subinhibitory concentrations of triclosan. Expression patterns of selected genes were verified by quantitative real-time PCR analysis. The results showed that triclosan exposure had a profound effect on gene expression, affecting 44% of the genes present on the Affymetrix GeneChip(®), with 28% of genes being significantly upregulated and 16% being significantly downregulated in triclosan-treated cells. Genes encoding membrane proteins, transporters of small molecules, aspects of amino acid metabolism, and transcriptional regulators were significantly over-represented among the more strongly upregulated or downregulated genes in triclosan-treated cells. Quorum sensing-regulated genes were among the most strongly downregulated genes, presumably because of decreased acyl-acyl carrier protein pools and the resulting reduced acyl-homoserine lactone molecule synthesis. Surprisingly, iron homeostasis was completed perturbed in triclosan-exposed cells, with iron acquisition systems being strongly downregulated and iron storage systems significantly upregulated, thus mimicking conditions of excess iron. The profound perturbations of cellular metabolism via specific and global mechanisms may explain why triclosan is such a potent antimicrobial in susceptible bacteria.
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Affiliation(s)
- Rungtip Chuanchuen
- Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand.
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39
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Orlandi VT, Caruso E, Banfi S, Barbieri P. Effect of Organic Matter on the In Vitro Photoeradication of Pseudomonas aeruginosa by Means of a Cationic Tetraaryl-porphyrin†. Photochem Photobiol 2012; 88:557-64. [DOI: 10.1111/j.1751-1097.2012.01122.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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40
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Jeon JM, Lee HI, Donati AJ, So JS, Emerich DW, Chang WS. Whole-genome expression profiling of Bradyrhizobium japonicum in response to hydrogen peroxide. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:1472-81. [PMID: 21864047 DOI: 10.1094/mpmi-03-11-0072] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Bradyrhizobium japonicum, a nitrogen-fixing bacterium in soil, establishes a symbiotic relationship with the leguminous soybean plant. Despite a mutualistic association between the two partners, the host plant produces an oxidative burst to protect itself from the invasion of rhizobial cells. We investigated the effects of H(2)O(2)-mediated oxidative stress on B. japonicum gene expression in both prolonged exposure (PE) and fulminant shock (FS) conditions. In total, 439 and 650 genes were differentially expressed for the PE and FS conditions, respectively, at a twofold cut-off with q < 0.05. A number of genes within the transport and binding proteins category were upregulated during PE and a majority of those genes are involved in ABC transporter systems. Many genes encoding ? factors, global stress response proteins, the FixK(2) transcription factor, and its regulatory targets were found to be upregulated in the FS condition. Surprisingly, catalase and peroxidase genes which are typically expressed in other bacteria under oxidative stress were not differentially expressed in either condition. The isocitrate lyase gene (aceA) was induced by fulminant H(2)O(2) shock, as was evident at both the transcriptional and translational levels. Interestingly, there was no significant effect of H(2)O(2) on exopolysaccharide production at the given experimental conditions.
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Affiliation(s)
- Jeong-Min Jeon
- Department of Biology, University of Texas, Arlington, TX, USA
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41
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Goldová J, Ulrych A, Hercík K, Branny P. A eukaryotic-type signalling system of Pseudomonas aeruginosa contributes to oxidative stress resistance, intracellular survival and virulence. BMC Genomics 2011; 12:437. [PMID: 21880152 PMCID: PMC3224232 DOI: 10.1186/1471-2164-12-437] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 08/31/2011] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The genome of Pseudomonas aeruginosa contains at least three genes encoding eukaryotic-type Ser/Thr protein kinases, one of which, ppkA, has been implicated in P. aeruginosa virulence. Together with the adjacent pppA phosphatase gene, they belong to the type VI secretion system (H1-T6SS) locus, which is important for bacterial pathogenesis. To determine the biological function of this protein pair, we prepared a pppA-ppkA double mutant and characterised its phenotype and transcriptomic profiles. RESULTS Phenotypic studies revealed that the mutant grew slower than the wild-type strain in minimal media and exhibited reduced secretion of pyoverdine. In addition, the mutant had altered sensitivity to oxidative and hyperosmotic stress conditions. Consequently, mutant cells had an impaired ability to survive in murine macrophages and an attenuated virulence in the plant model of infection. Whole-genome transcriptome analysis revealed that pppA-ppkA deletion affects the expression of oxidative stress-responsive genes, stationary phase σ-factor RpoS-regulated genes, and quorum-sensing regulons. The transcriptome of the pppA-ppkA mutant was also analysed under conditions of oxidative stress and showed an impaired response to the stress, manifested by a weaker induction of stress adaptation genes as well as the genes of the SOS regulon. In addition, expression of either RpoS-regulated genes or quorum-sensing-dependent genes was also affected. Complementation analysis confirmed that the transcription levels of the differentially expressed genes were specifically restored when the pppA and ppkA genes were expressed ectopically. CONCLUSIONS Our results suggest that in addition to its crucial role in controlling the activity of P. aeruginosa H1-T6SS at the post-translational level, the PppA-PpkA pair also affects the transcription of stress-responsive genes. Based on these data, it is likely that the reduced virulence of the mutant strain results from an impaired ability to survive in the host due to the limited response to stress conditions.
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Affiliation(s)
- Jana Goldová
- Cell and Molecular Microbiology Division, Institute of Microbiology of the ASCR, v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Aleš Ulrych
- Cell and Molecular Microbiology Division, Institute of Microbiology of the ASCR, v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic
| | - Kamil Hercík
- Cell and Molecular Microbiology Division, Institute of Microbiology of the ASCR, v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic
- Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pavel Branny
- Cell and Molecular Microbiology Division, Institute of Microbiology of the ASCR, v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic
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Hare NJ, Scott NE, Shin EHH, Connolly AM, Larsen MR, Palmisano G, Cordwell SJ. Proteomics of the oxidative stress response induced by hydrogen peroxide and paraquat reveals a novel AhpC-like protein in Pseudomonas aeruginosa. Proteomics 2011; 11:3056-69. [DOI: 10.1002/pmic.201000807] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 03/01/2011] [Accepted: 03/07/2011] [Indexed: 12/26/2022]
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Sanders LH, Devadoss B, Raja GV, O'Connor J, Su S, Wozniak DJ, Hassett DJ, Berdis AJ, Sutton MD. Epistatic roles for Pseudomonas aeruginosa MutS and DinB (DNA Pol IV) in coping with reactive oxygen species-induced DNA damage. PLoS One 2011; 6:e18824. [PMID: 21533111 PMCID: PMC3078926 DOI: 10.1371/journal.pone.0018824] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 03/10/2011] [Indexed: 12/04/2022] Open
Abstract
Pseudomonas aeruginosa is especially adept at colonizing the airways of individuals afflicted with the autosomal recessive disease cystic fibrosis (CF). CF patients suffer from chronic airway inflammation, which contributes to lung deterioration. Once established in the airways, P. aeruginosa continuously adapts to the changing environment, in part through acquisition of beneficial mutations via a process termed pathoadaptation. MutS and DinB are proposed to play opposing roles in P. aeruginosa pathoadaptation: MutS acts in replication-coupled mismatch repair, which acts to limit spontaneous mutations; in contrast, DinB (DNA polymerase IV) catalyzes error-prone bypass of DNA lesions, contributing to mutations. As part of an ongoing effort to understand mechanisms underlying P. aeruginosa pathoadaptation, we characterized hydrogen peroxide (H2O2)-induced phenotypes of isogenic P. aeruginosa strains bearing different combinations of mutS and dinB alleles. Our results demonstrate an unexpected epistatic relationship between mutS and dinB with respect to H2O2-induced cell killing involving error-prone repair and/or tolerance of oxidized DNA lesions. In striking contrast to these error-prone roles, both MutS and DinB played largely accurate roles in coping with DNA lesions induced by ultraviolet light, mitomycin C, or 4-nitroquinilone 1-oxide. Models discussing roles for MutS and DinB functionality in DNA damage-induced mutagenesis, particularly during CF airway colonization and subsequent P. aeruginosa pathoadaptation are discussed.
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Affiliation(s)
- Laurie H. Sanders
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, United States of America
- Witebsky Center for Microbial Pathogenesis and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, United States of America
| | - Babho Devadoss
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Geraldine V. Raja
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, United States of America
| | - Jaime O'Connor
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, United States of America
| | - Shengchang Su
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Daniel J. Wozniak
- Department of Infectious Disease and Microbiology, Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Daniel J. Hassett
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Anthony J. Berdis
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Mark D. Sutton
- Department of Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, United States of America
- Witebsky Center for Microbial Pathogenesis and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, United States of America
- * E-mail:
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Genome-wide transcriptional and physiological responses of Bradyrhizobium japonicum to paraquat-mediated oxidative stress. Appl Environ Microbiol 2011; 77:3633-43. [PMID: 21498770 DOI: 10.1128/aem.00047-11] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The rhizobial bacterium Bradyrhizobium japonicum functions as a nitrogen-fixing symbiont of the soybean plant (Glycine max). Plants are capable of producing an oxidative burst, a rapid proliferation of reactive oxygen species (ROS), as a defense mechanism against pathogenic and symbiotic bacteria. Therefore, B. japonicum must be able to resist such a defense mechanism to initiate nodulation. In this study, paraquat, a known superoxide radical-inducing agent, was used to investigate this response. Genome-wide transcriptional profiles were created for both prolonged exposure (PE) and fulminant shock (FS) conditions. These profiles revealed that 190 and 86 genes were up- and downregulated for the former condition, and that 299 and 105 genes were up- and downregulated for the latter condition, respectively (>2.0-fold; P < 0.05). Many genes within putative operons for F(0)F(1)-ATP synthase, chemotaxis, transport, and ribosomal proteins were upregulated during PE. The transcriptional profile for the FS condition strangely resembled that of a bacteroid condition, including the FixK(2) transcription factor and most of its response elements. However, genes encoding canonical ROS scavenging enzymes, such as superoxide dismutase and catalase, were not detected, suggesting constitutive expression of those genes by endogenous ROS. Various physiological tests, including exopolysaccharide (EPS), cellular protein, and motility characterization, were performed to corroborate the gene expression data. The results suggest that B. japonicum responds to tolerable oxidative stress during PE through enhanced motility, increased translational activity, and EPS production, in addition to the expression of genes involved in global stress responses, such as chaperones and sigma factors.
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Döring G, Parameswaran IG, Murphy TF. Differential adaptation of microbial pathogens to airways of patients with cystic fibrosis and chronic obstructive pulmonary disease. FEMS Microbiol Rev 2011; 35:124-46. [PMID: 20584083 DOI: 10.1111/j.1574-6976.2010.00237.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cystic fibrosis (CF), the most common autosomal recessive disorder in Caucasians, and chronic obstructive pulmonary disease (COPD), a disease of adults, are characterized by chronic lung inflammation, airflow obstruction and extensive tissue remodelling, which have a major impact on patients' morbidity and mortality. Airway inflammation is stimulated in CF by chronic bacterial infections and in COPD by environmental stimuli, particularly from smoking. Pseudomonas aeruginosa is the major bacterial pathogen in CF, while in COPD, Haemophilus influenzae is most frequently observed. Molecular studies indicate that during chronic pulmonary infection, P. aeruginosa clones genotypically and phenotypically adapt to the CF niche, resulting in a highly diverse bacterial community that is difficult to eradicate therapeutically. Pseudomonas aeruginosa clones from COPD patients remain within the airways only for limited time periods, do not adapt and are easily eradicated. However, in a subgroup of severely ill COPD patients, P. aeruginosa clones similar to those in CF persist. In this review, we will discuss the pathophysiology of lung disease in CF and COPD, the complex genotypic and phenotypic adaptation processes of the opportunistic bacterial pathogens and novel treatment options.
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Affiliation(s)
- Gerd Döring
- Institute of Medical Microbiology and Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany.
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Lee B, Schjerling CK, Kirkby N, Hoffmann N, Borup R, Molin S, Høiby N, Ciofu O. Mucoid Pseudomonas aeruginosa isolates maintain the biofilm formation capacity and the gene expression profiles during the chronic lung infection of CF patients. APMIS 2011; 119:263-74. [PMID: 21492226 DOI: 10.1111/j.1600-0463.2011.02726.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Phenotypic and genotypic diversifications of Pseudomonas aeruginosa in the airways of patients with cystic fibrosis (CF) promote long-term survival of bacteria during chronic lung infection. Twelve clonally related, sequential mucoid and non-mucoid paired P. aeruginosa isolates obtained from three Danish CF patients were investigated. The in vitro biofilm formation capacity was studied under static and flow through conditions and the global gene expression profiles were investigated by Affymetrix GeneChip. Regulatory genes of alginate production and quorum sensing (QS) system were sequenced and measurements of the alginate production and the detection of the QS signal molecules were performed. Comparisons of mucoid and non-mucoid isolates from early and late stages of the infection showed that the mucoid phenotype maintained over a decade the capacity to form in vitro biofilm and showed an unaltered transcriptional profile, whereas substantial alterations in the transcriptional profiles and loss of the capacity to form in vitro biofilms were observed in corresponding isolates of the non-mucoid phenotype. The conserved gene expression pattern in the mucoid isolates vs the diversity of changes in non-mucoid isolates observed in this particular P. aeruginosa clone reflects different adaptation strategies used by these two phenotypes in the different niches of the CF lung environment.
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Affiliation(s)
- Baoleri Lee
- Department of International Health, Immunology and Microbiology, Panum Institute, University of Copenhagen, Denmark
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Cleiss-Arnold J, Koechler S, Proux C, Fardeau ML, Dillies MA, Coppee JY, Arsène-Ploetze F, Bertin PN. Temporal transcriptomic response during arsenic stress in Herminiimonas arsenicoxydans. BMC Genomics 2010; 11:709. [PMID: 21167028 PMCID: PMC3022917 DOI: 10.1186/1471-2164-11-709] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2010] [Accepted: 12/17/2010] [Indexed: 02/02/2023] Open
Abstract
Background Arsenic is present in numerous ecosystems and microorganisms have developed various mechanisms to live in such hostile environments. Herminiimonas arsenicoxydans, a bacterium isolated from arsenic contaminated sludge, has acquired remarkable capabilities to cope with arsenic. In particular our previous studies have suggested the existence of a temporal induction of arsenite oxidase, a key enzyme in arsenic metabolism, in the presence of As(III). Results Microarrays were designed to compare gene transcription profiles under a temporal As(III) exposure. Transcriptome kinetic analysis demonstrated the existence of two phases in arsenic response. The expression of approximatively 14% of the whole genome was significantly affected by an As(III) early stress and 4% by an As(III) late exposure. The early response was characterized by arsenic resistance, oxidative stress, chaperone synthesis and sulfur metabolism. The late response was characterized by arsenic metabolism and associated mechanisms such as phosphate transport and motility. The major metabolic changes were confirmed by chemical, transcriptional, physiological and biochemical experiments. These early and late responses were defined as general stress response and specific response to As(III), respectively. Conclusion Gene expression patterns suggest that the exposure to As(III) induces an acute response to rapidly minimize the immediate effects of As(III). Upon a longer arsenic exposure, a broad metabolic response was induced. These data allowed to propose for the first time a kinetic model of the As(III) response in bacteria.
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Affiliation(s)
- Jessica Cleiss-Arnold
- Département Microorganismes, UMR7156 Université de Strasbourg/CNRS, Génétique Moléculaire, Génomique et Microbiologie, 28 rue Goethe, 67083 Strasbourg cedex, France
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Folsom JP, Richards L, Pitts B, Roe F, Ehrlich GD, Parker A, Mazurie A, Stewart PS. Physiology of Pseudomonas aeruginosa in biofilms as revealed by transcriptome analysis. BMC Microbiol 2010; 10:294. [PMID: 21083928 PMCID: PMC2998477 DOI: 10.1186/1471-2180-10-294] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 11/17/2010] [Indexed: 11/23/2022] Open
Abstract
Background Transcriptome analysis was applied to characterize the physiological activities of Pseudomonas aeruginosa grown for three days in drip-flow biofilm reactors. Conventional applications of transcriptional profiling often compare two paired data sets that differ in a single experimentally controlled variable. In contrast this study obtained the transcriptome of a single biofilm state, ranked transcript signals to make the priorities of the population manifest, and compared ranki ngs for a priori identified physiological marker genes between the biofilm and published data sets. Results Biofilms tolerated exposure to antibiotics, harbored steep oxygen concentration gradients, and exhibited stratified and heterogeneous spatial patterns of protein synthetic activity. Transcriptional profiling was performed and the signal intensity of each transcript was ranked to gain insight into the physiological state of the biofilm population. Similar rankings were obtained from data sets published in the GEO database http://www.ncbi.nlm.nih.gov/geo. By comparing the rank of genes selected as markers for particular physiological activities between the biofilm and comparator data sets, it was possible to infer qualitative features of the physiological state of the biofilm bacteria. These biofilms appeared, from their transcriptome, to be glucose nourished, iron replete, oxygen limited, and growing slowly or exhibiting stationary phase character. Genes associated with elaboration of type IV pili were strongly expressed in the biofilm. The biofilm population did not indicate oxidative stress, homoserine lactone mediated quorum sensing, or activation of efflux pumps. Using correlations with transcript ranks, the average specific growth rate of biofilm cells was estimated to be 0.08 h-1. Conclusions Collectively these data underscore the oxygen-limited, slow-growing nature of the biofilm population and are consistent with antimicrobial tolerance due to low metabolic activity.
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Affiliation(s)
- James P Folsom
- Center for Biofilm Engineering and Department of Chemical and Biological Engineering, PO Box 173980, Montana State University-Bozeman, Bozeman, Montana 59717-3980, USA
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Tremblay J, Déziel E. Gene expression in Pseudomonas aeruginosa swarming motility. BMC Genomics 2010; 11:587. [PMID: 20961425 PMCID: PMC3091734 DOI: 10.1186/1471-2164-11-587] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 10/20/2010] [Indexed: 12/25/2022] Open
Abstract
Background The bacterium Pseudomonas aeruginosa is capable of three types of motilities: swimming, twitching and swarming. The latter is characterized by a fast and coordinated group movement over a semi-solid surface resulting from intercellular interactions and morphological differentiation. A striking feature of swarming motility is the complex fractal-like patterns displayed by migrating bacteria while they move away from their inoculation point. This type of group behaviour is still poorly understood and its characterization provides important information on bacterial structured communities such as biofilms. Using GeneChip® Affymetrix microarrays, we obtained the transcriptomic profiles of both bacterial populations located at the tip of migrating tendrils and swarm center of swarming colonies and compared these profiles to that of a bacterial control population grown on the same media but solidified to not allow swarming motility. Results Microarray raw data were corrected for background noise with the RMA algorithm and quantile normalized. Differentially expressed genes between the three conditions were selected using a threshold of 1.5 log2-fold, which gave a total of 378 selected genes (6.3% of the predicted open reading frames of strain PA14). Major shifts in gene expression patterns are observed in each growth conditions, highlighting the presence of distinct bacterial subpopulations within a swarming colony (tendril tips vs. swarm center). Unexpectedly, microarrays expression data reveal that a minority of genes are up-regulated in tendril tip populations. Among them, we found energy metabolism, ribosomal protein and transport of small molecules related genes. On the other hand, many well-known virulence factors genes were globally repressed in tendril tip cells. Swarm center cells are distinct and appear to be under oxidative and copper stress responses. Conclusions Results reported in this study show that, as opposed to swarm center cells, tendril tip populations of a swarming colony displays general down-regulation of genes associated with virulence and up-regulation of genes involved in energy metabolism. These results allow us to propose a model where tendril tip cells function as «scouts» whose main purpose is to rapidly spread on uncolonized surfaces while swarm center population are in a state allowing a permanent settlement of the colonized area (biofilm-like).
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Affiliation(s)
- Julien Tremblay
- INRS-Institut Armand-Frappier, Laval (Québec), H7V 1B7, Canada
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Frimmersdorf E, Horatzek S, Pelnikevich A, Wiehlmann L, Schomburg D. How Pseudomonas aeruginosa adapts to various environments: a metabolomic approach. Environ Microbiol 2010; 12:1734-47. [PMID: 20553553 DOI: 10.1111/j.1462-2920.2010.02253.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In addition to transcriptome and proteome studies, metabolome analysis represents a third complementary approach to identify metabolic pathways and adaptation processes. In order to elucidate basic principles of metabolic versatility of Pseudomonas aeruginosa, we investigated the metabolome profiles of two genetically and morphologically divergent strains, the reference strain PAO1 and the mucoid clinical isolate TBCF10839 in exponential growth and stationary phase in six different carbon sources (cadaverine, casamino acids, citrate, glucose, succinate and tryptone). Both strains exhibited strong similarities in mode of growth; the metabolite patterns were mainly defined by the growth condition. Besides this adaptive response, a basic core metabolism shapes the P. aeruginosa metabolome, independent of growth phase, carbon source and genetic background. This core metabolism includes pathways related to the central energy and amino acid metabolism. These consistently utilized metabolic pathways are closely related to glutamate which represents a dominant metabolite in all conditions analysed. In nutrient-depleted media of stationary phase cultures, P. aeruginosa maintains a specific repertoire of metabolic pathways that are related to the carbon source formerly available. This specified adaptation strategy combined with the invariant basic core metabolism may represent a fundamental requirement for the metabolic versatility of this organism.
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Affiliation(s)
- Eliane Frimmersdorf
- Department of Biochemistry and Bioinformatics, Institute for Biochemistry & Biotechnology, Technische Universitaet Braunschweig, 38106 Braunschweig, Germany
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