1
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Cho THS, Murray C, Malpica R, Margain-Quevedo R, Thede GL, Lu J, Edwards RA, Glover JNM, Raivio TL. The sensor of the bacterial histidine kinase CpxA is a novel dimer of extracytoplasmic Per-ARNT-Sim domains. J Biol Chem 2024; 300:107265. [PMID: 38582452 PMCID: PMC11078701 DOI: 10.1016/j.jbc.2024.107265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 03/17/2024] [Accepted: 03/29/2024] [Indexed: 04/08/2024] Open
Abstract
Histidine kinases are key bacterial sensors that recognize diverse environmental stimuli. While mechanisms of phosphorylation and phosphotransfer by cytoplasmic kinase domains are relatively well-characterized, the ways in which extracytoplasmic sensor domains regulate activation remain mysterious. The Cpx envelope stress response is a conserved Gram-negative two-component system which is controlled by the sensor kinase CpxA. We report the structure of the Escherichia coli CpxA sensor domain (CpxA-SD) as a globular Per-ARNT-Sim (PAS)-like fold highly similar to that of Vibrio parahaemolyticus CpxA as determined by X-ray crystallography. Because sensor kinase dimerization is important for signaling, we used AlphaFold2 to model CpxA-SD in the context of its connected transmembrane domains, which yielded a novel dimer of PAS domains possessing a distinct dimer organization compared to previously characterized sensor domains. Gain of function cpxA∗ alleles map to the dimer interface, and mutation of other residues in this region also leads to constitutive activation. CpxA activation can be suppressed by mutations that restore inter-monomer interactions, suggesting that inhibitory interactions between CpxA-SD monomers are the major point of control for CpxA activation and signaling. Searching through hundreds of structural homologs revealed the sensor domain of Pseudomonas aeruginosa sensor kinase PfeS as the only PAS structure in the same novel dimer orientation as CpxA, suggesting that our dimer orientation may be utilized by other extracytoplasmic PAS domains. Overall, our findings provide insight into the diversity of the organization of PAS sensory domains and how they regulate sensor kinase activation.
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Affiliation(s)
- Timothy H S Cho
- Departments of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Cameron Murray
- Departments of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Roxana Malpica
- Departments of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; Instituto de Ciencias Biomédicas, Universidad Autónoma de Ciudad Juárez, Chihuahua, México
| | | | - Gina L Thede
- Departments of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jun Lu
- Departments of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada; Departments of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ross A Edwards
- Departments of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - J N Mark Glover
- Departments of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Tracy L Raivio
- Departments of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.
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2
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Hubert T, Madec M, Schalk IJ. Experimental and computational methods to highlight behavioural variations in TonB-dependent transporter expression in Pseudomonas aeruginosa versus siderophore concentration. Sci Rep 2023; 13:20015. [PMID: 37974013 PMCID: PMC10654771 DOI: 10.1038/s41598-023-46585-z] [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: 07/25/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
Iron is a key nutrient for bacterial growth. The source can be either heme or siderophore-Fe complexes. Siderophores are small molecules synthesized by bacteria to scavenge iron from the bacterial environment. The pathogen Pseudomonas aeruginosa can express at least 15 different iron uptake pathways and all but one involve a TonB-dependent transporter (TBDT) for the uptake of iron across the outer membrane. Little is known about how bacteria modulate and adapt the expression of their different iron import pathways according to their environment. Here, we have developed fluorescent reporters between the promoter region of genes encoding a TBDT and the fluorescent reporter mCherry. With these constructs, we can follow the expression of TBDTs under different growth conditions. Mathematical modelling of the data obtained showed the transcription and expression of the gene encoding the TBDT PfeA to have a sigmoidal shape, whereas it was logarithmic for the TBDT gene foxA. Maximum transcription for pfeA was reached in the presence of 3 µM enterobactin, the siderophore recognized by PfeA, whereas the maximum was not reached for foxA with 100 µM nocardamine, the siderophore of FoxA.
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Affiliation(s)
- Thibaut Hubert
- CNRS, UMR7242, ESBS, University of Strasbourg, Bld Sébastien Brant, 67412, Illkirch, Strasbourg, France
- ICube Laboratory, CNRS, UMR 7357, University of Strasbourg, Bld Sébastien Brant, 67412, Illkirch, Strasbourg, France
| | - Morgan Madec
- ICube Laboratory, CNRS, UMR 7357, University of Strasbourg, Bld Sébastien Brant, 67412, Illkirch, Strasbourg, France.
| | - Isabelle J Schalk
- CNRS, UMR7242, ESBS, University of Strasbourg, Bld Sébastien Brant, 67412, Illkirch, Strasbourg, France.
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3
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Kalpana S, Lin WY, Wang YC, Fu Y, Lakshmi A, Wang HY. Antibiotic Resistance Diagnosis in ESKAPE Pathogens-A Review on Proteomic Perspective. Diagnostics (Basel) 2023; 13:1014. [PMID: 36980322 PMCID: PMC10047325 DOI: 10.3390/diagnostics13061014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 02/26/2023] [Accepted: 02/28/2023] [Indexed: 03/11/2023] Open
Abstract
Antibiotic resistance has emerged as an imminent pandemic. Rapid diagnostic assays distinguish bacterial infections from other diseases and aid antimicrobial stewardship, therapy optimization, and epidemiological surveillance. Traditional methods typically have longer turn-around times for definitive results. On the other hand, proteomic studies have progressed constantly and improved both in qualitative and quantitative analysis. With a wide range of data sets made available in the public domain, the ability to interpret the data has considerably reduced the error rates. This review gives an insight on state-of-the-art proteomic techniques in diagnosing antibiotic resistance in ESKAPE pathogens with a future outlook for evading the "imminent pandemic".
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Affiliation(s)
- Sriram Kalpana
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan 333423, Taiwan
| | | | - Yu-Chiang Wang
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
| | - Yiwen Fu
- Department of Medicine, Kaiser Permanente Santa Clara Medical Center, Santa Clara, CA 95051, USA
| | - Amrutha Lakshmi
- Department of Biochemistry, University of Madras, Guindy Campus, Chennai 600025, India
| | - Hsin-Yao Wang
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan 333423, Taiwan
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4
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Sánchez-Jiménez A, Marcos-Torres FJ, Llamas MA. Mechanisms of iron homeostasis in Pseudomonas aeruginosa and emerging therapeutics directed to disrupt this vital process. Microb Biotechnol 2023. [PMID: 36857468 DOI: 10.1111/1751-7915.14241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 02/13/2023] [Indexed: 03/03/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen able to infect any human tissue. One of the reasons for its high adaptability and colonization of host tissues is its capacity of maintaining iron homeostasis through a wide array of iron acquisition and removal mechanisms. Due to their ability to cause life-threatening acute and chronic infections, especially among cystic fibrosis and immunocompromised patients, and their propensity to acquire resistance to many antibiotics, the World Health Organization (WHO) has encouraged the scientific community to find new strategies to eradicate this pathogen. Several recent strategies to battle P. aeruginosa focus on targeting iron homeostasis mechanisms, turning its greatest advantage into an exploitable weak point. In this review, we discuss the different mechanisms used by P. aeruginosa to maintain iron homeostasis and the strategies being developed to fight this pathogen by blocking these mechanisms. Among others, the use of iron chelators and mimics, as well as disruption of siderophore production and uptake, have shown promising results in reducing viability and/or virulence of this pathogen. The so-called 'Trojan-horse' strategy taking advantage of the siderophore uptake systems is emerging as an efficient method to improve delivery of antibiotics into the bacterial cells. Moreover, siderophore transporters are considered promising targets for the developing of P. aeruginosa vaccines.
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Affiliation(s)
- Ana Sánchez-Jiménez
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Francisco J Marcos-Torres
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - María A Llamas
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain
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5
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Schalk IJ, Perraud Q. Pseudomonas aeruginosa and its multiple strategies to access iron. Environ Microbiol 2022; 25:811-831. [PMID: 36571575 DOI: 10.1111/1462-2920.16328] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/21/2022] [Indexed: 12/27/2022]
Abstract
Pseudomonas aeruginosa is a ubiquitous bacterium found in many natural and man-made environments. It is also a pathogen for plants, animals, and humans. As for almost all living organisms, iron is an essential nutrient for the growth of P. aeruginosa. The bacterium has evolved complex systems to access iron and maintain its homeostasis to survive in diverse natural and dynamic host environments. To access ferric iron, P. aeruginosa is able to produce two siderophores (pyoverdine and pyochelin), as well as use a variety of siderophores produced by other bacteria (mycobactins, enterobactin, ferrioxamine, ferrichrome, vibriobactin, aerobactin, rhizobactin and schizokinen). Furthermore, it can also use citrate, in addition to catecholamine neuromediators and plant-derived mono catechols, as siderophores. The P. aeruginosa genome also encodes three heme-uptake pathways (heme being an iron source) and one ferrous iron acquisition pathway. This review aims to summarize current knowledge concerning the molecular mechanisms involved in all the iron and heme acquisition strategies used by P. aeruginosa.
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Affiliation(s)
- Isabelle J Schalk
- CNRS, UMR7242, ESBS, Strasbourg, France.,University of Strasbourg, UMR7242, ESBS, Strasbourg, France
| | - Quentin Perraud
- CNRS, UMR7242, ESBS, Strasbourg, France.,University of Strasbourg, UMR7242, ESBS, Strasbourg, France
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6
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Molecular Characteristics and Quantitative Proteomic Analysis of Klebsiella pneumoniae Strains with Carbapenem and Colistin Resistance. Antibiotics (Basel) 2022; 11:antibiotics11101341. [PMID: 36289999 PMCID: PMC9598126 DOI: 10.3390/antibiotics11101341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/27/2022] [Accepted: 09/29/2022] [Indexed: 12/05/2022] Open
Abstract
Carbapenem-resistant Klebsiella pneumoniae (CRKP) are usually multidrug resistant (MDR) and cause serious therapeutic problems. Colistin is a critical last-resort therapeutic option for MDR bacterial infections. However, increasing colistin use has led to the emergence of extensively drug-resistant (XDR) strains, raising a significant challenge for healthcare. In order to gain insight into the antibiotic resistance mechanisms of CRKP and identify potential drug targets, we compared the molecular characteristics and the proteomes among drug-sensitive (DS), MDR, and XDR K. pneumoniae strains. All drug-resistant isolates belonged to ST11, harboring blaKPC and hypervirulent genes. None of the plasmid-encoded mcr genes were detected in the colistin-resistant XDR strains. Through a tandem mass tag (TMT)-labeled proteomic technique, a total of 3531 proteins were identified in the current study. Compared to the DS strains, there were 247 differentially expressed proteins (DEPs) in the MDR strains and 346 DEPs in the XDR strains, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that a majority of the DEPs were involved in various metabolic pathways, which were beneficial to the evolution of drug resistance in K. pneumoniae. In addition, a total of 67 DEPs were identified between the MDR and XDR strains. KEGG enrichment and protein-protein interaction network analysis showed their participation in cationic antimicrobial peptide resistance and two-component systems. In conclusion, our results highlight the emergence of colistin-resistant and hypervirulent CRKP, which is a noticeable superbug. The DEPs identified in our study are of great significance for the exploration of effective control strategies against infections of CRKP.
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7
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Moynié L, Hoegy F, Milenkovic S, Munier M, Paulen A, Gasser V, Faucon AL, Zill N, Naismith JH, Ceccarelli M, Schalk IJ, Mislin GLA. Hijacking of the Enterobactin Pathway by a Synthetic Catechol Vector Designed for Oxazolidinone Antibiotic Delivery in Pseudomonas aeruginosa. ACS Infect Dis 2022; 8:1894-1904. [PMID: 35881068 DOI: 10.1021/acsinfecdis.2c00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Enterobactin (ENT) is a tris-catechol siderophore used to acquire iron by multiple bacterial species. These ENT-dependent iron uptake systems have often been considered as potential gates in the bacterial envelope through which one can shuttle antibiotics (Trojan horse strategy). In practice, siderophore analogues containing catechol moieties have shown promise as vectors to which antibiotics may be attached. Bis- and tris-catechol vectors (BCVs and TCVs, respectively) were shown using structural biology and molecular modeling to mimic ENT binding to the outer membrane transporter PfeA in Pseudomonas aeruginosa. TCV but not BCV appears to cross the outer membrane via PfeA when linked to an antibiotic (linezolid). TCV is therefore a promising vector for Trojan horse strategies against P. aeruginosa, confirming the ENT-dependent iron uptake system as a gate to transport antibiotics into P. aeruginosa cells.
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Affiliation(s)
- Lucile Moynié
- The Rosalind Franklin Institute, Harwell Campus, Oxfordshire OX11 0QS, U.K
| | - Françoise Hoegy
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Stefan Milenkovic
- Department of Physics, University of Cagliari, 09042 Monserrato, Italy
| | - Mathilde Munier
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Aurélie Paulen
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Véronique Gasser
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Aline L Faucon
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Nicolas Zill
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - James H Naismith
- The Rosalind Franklin Institute, Harwell Campus, Oxfordshire OX11 0QS, U.K.,Division of Structural Biology, Wellcome Trust Centre of Human Genomics, 7 Roosevelt Drive, Oxford OX3 7BN, U.K
| | - Matteo Ceccarelli
- Department of Physics, University of Cagliari, 09042 Monserrato, Italy.,IOM/CNR, Sezione di Cagliari, University of Cagliari, 09042 Monserrato, Italy
| | - Isabelle J Schalk
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Gaëtan L A Mislin
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
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8
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Plant-Derived Catechols Are Substrates of TonB-Dependent Transporters and Sensitize Pseudomonas aeruginosa to Siderophore-Drug Conjugates. mBio 2022; 13:e0149822. [PMID: 35770947 PMCID: PMC9426570 DOI: 10.1128/mbio.01498-22] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen responsible for acute and chronic infections in immunocompromised hosts. This organism is known to compete efficiently against coinfecting microorganisms, due in part to the secretion of antimicrobial molecules and the synthesis of siderophore molecules with high affinity for iron. P. aeruginosa possess a large repertoire of TonB-dependent transporters for the uptake of its own, as well as xenosiderophores released from other bacteria or fungi. Here, we show that P. aeruginosa is also capable of utilizing plant-derived polyphenols as an iron source. We found that exclusively plant-derived phenols containing a catechol group (i.e., chlorogenic acid, caffeic acid, quercetin, luteolin) induce the expression of the TonB-dependent transporters PiuA or PirA. This induction requires the two-component system PirR-PirS. Chlorogenic acid in its Fe(III)-loaded form was actively transported by PiuA and PirA and supported growth under iron-limiting conditions. Coincidentally, PiuA and PirA are also the main TonB transporters for the recently approved siderophore-drug conjugate cefiderocol. Surprisingly, quercetin supplementation increased the susceptibility of P. aeruginosa to siderophore-drug conjugates, due to induction of piuA and pirA expression mediated by the PirR-PirS two-component system. These findings suggest a potential novel therapeutic application for these biologically active dietary polyphenols.
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9
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Fritsch S, Gasser V, Peukert C, Pinkert L, Kuhn L, Perraud Q, Normant V, Brönstrup M, Schalk IJ. Uptake Mechanisms and Regulatory Responses to MECAM- and DOTAM-Based Artificial Siderophores and Their Antibiotic Conjugates in Pseudomonas aeruginosa. ACS Infect Dis 2022; 8:1134-1146. [PMID: 35500104 DOI: 10.1021/acsinfecdis.2c00049] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The development of new antibiotics against Gram-negative bacteria has to deal with the low permeability of the outer membrane. This obstacle can be overcome by utilizing siderophore-dependent iron uptake pathways as entrance routes for antibiotic uptake. Iron-chelating siderophores are actively imported by bacteria, and their conjugation to antibiotics allows smuggling the latter into bacterial cells. Synthetic siderophore mimetics based on MECAM (1,3,5-N,N',N″-tris-(2,3-dihydroxybenzoyl)-triaminomethylbenzene) and DOTAM (1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane) cores, both chelating iron via catechol groups, have been recently applied as versatile carriers of functional cargo. In the present study, we show that MECAM and the MECAM-ampicillin conjugate 3 transport iron into Pseudomonas aeruginosa cells via the catechol-type outer membrane transporters PfeA and PirA and DOTAM solely via PirA. Differential proteomics and quantitative real-time polymerase chain reaction (qRT-PCR) showed that MECAM import induced the expression of pfeA, whereas 3 led to an increase in the expression of pfeA and ampc, a gene conferring ampicillin resistance. The presence of DOTAM did not induce the expression of pirA but upregulated the expression of two zinc transporters (cntO and PA0781), pointing out that bacteria become zinc starved in the presence of this compound. Iron uptake experiments with radioactive 55Fe demonstrated that import of this nutrient by MECAM and DOTAM was as efficient as with the natural siderophore enterobactin. The study provides a functional validation for DOTAM- and MECAM-based artificial siderophore mimetics as vehicles for the delivery of cargo into Gram-negative bacteria.
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Affiliation(s)
- Sarah Fritsch
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Véronique Gasser
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Carsten Peukert
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany
| | - Lukas Pinkert
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, Strasbourg Cedex F-67084, France
| | - Quentin Perraud
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Vincent Normant
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany
- German Center for Infection Research (DZIF), Site Hannover-Braunschweig, Braunschweig 38124, Germany
- Center of Biomolecular Drug Research (BMWZ), Leibniz Universität, Hannover 30159, Germany
| | - Isabelle J. Schalk
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
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10
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Normant V, Kuhn L, Munier M, Hammann P, Mislin GLA, Schalk IJ. How the Presence of Hemin Affects the Expression of the Different Iron Uptake Pathways in Pseudomonas aeruginosa Cells. ACS Infect Dis 2022; 8:183-196. [PMID: 34878758 DOI: 10.1021/acsinfecdis.1c00525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron is an essential nutriment for almost all organisms, but this metal is poorly bioavailable. During infection, bacteria access iron from the host by importing either iron or heme. Pseudomonas aeruginosa, a gram-negative pathogen, secretes two siderophores, pyoverdine (PVD) and pyochelin (PCH), to access iron and is also able to use many siderophores produced by other microorganisms (called xenosiderophores). To access heme, P. aeruginosa uses three distinct uptake pathways, named Has, Phu, and Hxu. We previously showed that P. aeruginosa expresses the Has and Phu heme uptake systems and the PVD- and PCH-dependent iron uptake pathways in iron-restricted growth conditions, using proteomic and RT-qPCR approaches. Here, using the same approaches, we show that physiological concentrations of hemin in the bacterial growth medium result in the repression of the expression of the proteins of the PVD- and PCH-dependent iron uptake pathways, leading to less production of these two siderophores. This indicates that the pathogen adapts its phenotype to use hemin as an iron source rather than produce PVD and PCH to access iron. Moreover, the presence of both hemin and a xenosiderophore resulted in (i) the strong induction of the expression of the proteins of the added xenosiderophore uptake pathway, (ii) repression of the PVD- and PCH-dependent iron uptake pathways, and (iii) no effect on the expression levels of the Has, Phu, or Hxu systems, indicating that bacteria use both xenosiderophores and heme to access iron.
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Affiliation(s)
- Vincent Normant
- CNRS/Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67412 Strasbourg, France
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Mathilde Munier
- CNRS/Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67412 Strasbourg, France
| | - Philippe Hammann
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Gaëtan L. A. Mislin
- CNRS/Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67412 Strasbourg, France
| | - Isabelle J. Schalk
- CNRS/Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, Illkirch, F-67412 Strasbourg, France
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11
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Iron Homeostasis in Pseudomonas aeruginosa: Targeting Iron Acquisition and Storage as an Antimicrobial Strategy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:29-68. [DOI: 10.1007/978-3-031-08491-1_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Two TonB-dependent transporters in Methylosinus trichosporium OB3b are responsible for uptake of different forms of methanobactin and are involved in the canonical 'copper switch'. Appl Environ Microbiol 2021; 88:e0179321. [PMID: 34669437 DOI: 10.1128/aem.01793-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Copper is an important component of methanotrophic physiology as it controls the expression and activity of alternative forms of methane monooxygenase (MMO). To collect copper, some methanotrophs secrete a chalkophore or copper-binding compound called methanobactin (MB). MB is a ribosomally synthesized post-translationally modified polypeptide (RiPP) that, after binding copper, is collected by MbnT, a TonB-dependent transporter (TBDT). Structurally different forms of MB have been characterized, and here we show that different forms of MB are collected by specific TBDTs. Further, we report that in the model methanotroph, Methylosinus trichosporium OB3b, expression of the TBDT required for uptake of a different MB made by Methylocystis sp. strain SB2 (MB-SB2), is induced in the presence of MB-SB2, suggesting that methanotrophs have developed specific machinery and regulatory systems to actively take up MB from other methanotrophs for copper collection. Moreover, the canonical "copper-switch" in Ms. trichosporium OB3b that controls expression of alternative MMOs is apparent if one of the two TBDTs required for MB-OB3b and MB-SB2 uptake is knocked out, but is disrupted if both TBDTs are knocked out. These data indicate that MB uptake, including the uptake of exogenous MB, plays an important role in the copper switch in M. trichosporium OB3b and thus overall activity. Based on these data, we propose a revised model for the "copper-switch" in this methanotroph that involves MB uptake. IMPORTANCE In this study, we demonstrate that different TonB-dependent transporters (TBDTs) in the model methanotroph Methylosinus trichosporium OB3b are responsible for uptake of either endogenous MB or exogenous MB. Interestingly, the presence of exogenous MB induces expression of its specific TBDT in M. trichosporium OB3b, suggesting that this methanotroph is able to actively take up MB produced by others. This work contributes to our understanding of how microbes collect and compete for copper, and also helps inform how such uptake coordinates the expression of different forms of methane monooxygenase. Such studies are likely to be very important to develop a better understanding of methanotrophic interactions via synthesis and secretion of secondary metabolites such as methanobactin and thus provide additional means whereby these microbes can be manipulated for a variety of environmental and industrial purposes.
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13
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Klebba PE, Newton SMC, Six DA, Kumar A, Yang T, Nairn BL, Munger C, Chakravorty S. Iron Acquisition Systems of Gram-negative Bacterial Pathogens Define TonB-Dependent Pathways to Novel Antibiotics. Chem Rev 2021; 121:5193-5239. [PMID: 33724814 PMCID: PMC8687107 DOI: 10.1021/acs.chemrev.0c01005] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iron is an indispensable metabolic cofactor in both pro- and eukaryotes, which engenders a natural competition for the metal between bacterial pathogens and their human or animal hosts. Bacteria secrete siderophores that extract Fe3+ from tissues, fluids, cells, and proteins; the ligand gated porins of the Gram-negative bacterial outer membrane actively acquire the resulting ferric siderophores, as well as other iron-containing molecules like heme. Conversely, eukaryotic hosts combat bacterial iron scavenging by sequestering Fe3+ in binding proteins and ferritin. The variety of iron uptake systems in Gram-negative bacterial pathogens illustrates a range of chemical and biochemical mechanisms that facilitate microbial pathogenesis. This document attempts to summarize and understand these processes, to guide discovery of immunological or chemical interventions that may thwart infectious disease.
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Affiliation(s)
- Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Salete M C Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - David A Six
- Venatorx Pharmaceuticals, Inc., 30 Spring Mill Drive, Malvern, Pennsylvania 19355, United States
| | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Brittany L Nairn
- Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, Minnesota 55112, United States
| | - Colton Munger
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Somnath Chakravorty
- Jacobs School of Medicine and Biomedical Sciences, SUNY Buffalo, Buffalo, New York 14203, United States
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14
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Wang X, Zhang M, Loh B, Leptihn S, Ahmed T, Li B. A novel NRPS cluster, acquired by horizontal gene transfer from algae, regulates siderophore iron metabolism in Burkholderia seminalis R456. Int J Biol Macromol 2021; 182:838-848. [PMID: 33862079 DOI: 10.1016/j.ijbiomac.2021.04.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/06/2021] [Accepted: 04/07/2021] [Indexed: 11/27/2022]
Abstract
In an environment with limited iron levels, sufficiently high intracellular iron concentrations are critical for bacterial survival. When iron levels are low, many bacteria including those of the Burkholderia cepacia group secrete chemically diverse siderophores to capture Fe3+. The synthesis of the two main siderophores, ornibactin and pyochelin, is regulated in an iron concentration dependent manner via the regulator protein Fur. In this study, we identified a novel Nonribosomal Peptide Synthetase (NRPS) cluster in strain R456 of Burkholderia seminalis, a member of the B. cepacia group. We show that the NRPS cluster not only allows the production of a so-far undescribed siderophore, but is also required for ornibactin and pyochelin production as it is a crucial component in the signaling pathway targeting the global iron regulating effector Fur which regulates siderophore production. Furthermore, the NRPS cluster is also involved in cell motility and biofilm formation, both of which are directly dependent on iron concentration in various bacteria. Interestingly, our data suggests that this newly discovered NRPS cluster which regulates siderophore iron metabolism in bacteria was obtained by horizontal gene transfer from algae.
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Affiliation(s)
- Xiaoxuan Wang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058 Hangzhou, China
| | - Muchen Zhang
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058 Hangzhou, China
| | - Belinda Loh
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Hangzhou 314400, China
| | - Sebastian Leptihn
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Hangzhou 314400, China
| | - Temoor Ahmed
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058 Hangzhou, China
| | - Bin Li
- State Key Laboratory of Rice Biology and Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058 Hangzhou, China.
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15
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Umasuthan N, Valderrama K, Vasquez I, Segovia C, Hossain A, Cao T, Gnanagobal H, Monk J, Boyce D, Santander J. A Novel Marine Pathogen Isolated from Wild Cunners ( Tautogolabrus adspersus): Comparative Genomics and Transcriptome Profiling of Pseudomonas sp. Strain J380. Microorganisms 2021; 9:812. [PMID: 33921528 PMCID: PMC8069873 DOI: 10.3390/microorganisms9040812] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 12/13/2022] Open
Abstract
Cunner (Tautogolabrus adspersus) is a cleaner fish being considered for utilized in the North Atlantic salmon (Salmo salar) aquaculture industry to biocontrol sea lice infestations. However, bacterial diseases due to natural infections in wild cunners have yet to be described. This study reports the isolation of Pseudomonas sp. J380 from infected wild cunners and its phenotypic, genomic, and transcriptomic characterization. This Gram-negative motile rod-shaped bacterium showed a mesophilic (4-28 °C) and halotolerant growth. Under iron-limited conditions, Pseudomonas sp. J380 produced pyoverdine-type fluorescent siderophore. Koch's postulates were verified in wild cunners by intraperitoneally (i.p.) injecting Pseudomonas sp. J380 at 4 × 103, 4 × 105, and 4 × 107 colony forming units (CFU)/dose. Host-range and comparative virulence were also investigated in lumpfish and Atlantic salmon i.p. injected with ~106 CFU/dose. Lumpfish were more susceptible compared to cunners, and Atlantic salmon was resistant to Pseudomonas sp. J380 infection. Cunner tissues were heavily colonized by Pseudomonas sp. J380 compared to lumpfish and Atlantic salmon suggesting that it might be an opportunistic pathogen in cunners. The genome of Pseudomonas sp. J380 was 6.26 megabases (Mb) with a guanine-cytosine (GC) content of 59.7%. Biochemical profiles, as well as comparative and phylogenomic analyses, suggested that Pseudomonas sp. J380 belongs to the P. fluorescens species complex. Transcriptome profiling under iron-limited vs. iron-enriched conditions identified 1159 differentially expressed genes (DEGs). Cellular metabolic processes, such as ribosomal and energy production, and protein synthesis, were impeded by iron limitation. In contrast, genes involved in environmental adaptation mechanisms including two-component systems, histidine catabolism, and redox balance were transcriptionally up-regulated. Furthermore, iron limitation triggered the differential expression of genes encoding proteins associated with iron homeostasis. As the first report on a bacterial infection in cunners, the current study provides an overview of a new marine pathogen, Pseudomonas sp. J380.
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Affiliation(s)
- Navaneethaiyer Umasuthan
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Katherinne Valderrama
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Ignacio Vasquez
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Cristopher Segovia
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Ahmed Hossain
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Trung Cao
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Hajarooba Gnanagobal
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
| | - Jennifer Monk
- Dr. Joe Brown Aquatic Research Building (JBARB), Department of Ocean Sciences, Memorial University of Newfoundland, Logy Bay, NL A1C 5S7, Canada; (J.M.); (D.B.)
| | - Danny Boyce
- Dr. Joe Brown Aquatic Research Building (JBARB), Department of Ocean Sciences, Memorial University of Newfoundland, Logy Bay, NL A1C 5S7, Canada; (J.M.); (D.B.)
| | - Javier Santander
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada; (N.U.); (K.V.); (I.V.); (C.S.); (A.H.); (T.C.); (H.G.)
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16
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Gasser V, Kuhn L, Hubert T, Aussel L, Hammann P, Schalk IJ. The Esterase PfeE, the Achilles' Heel in the Battle for Iron between Pseudomonas aeruginosa and Escherichia coli. Int J Mol Sci 2021; 22:ijms22062814. [PMID: 33802163 PMCID: PMC8001512 DOI: 10.3390/ijms22062814] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/23/2021] [Accepted: 03/02/2021] [Indexed: 11/16/2022] Open
Abstract
Bacteria access iron, a key nutrient, by producing siderophores or using siderophores produced by other microorganisms. The pathogen Pseudomonas aeruginosa produces two siderophores but is also able to pirate enterobactin (ENT), the siderophore produced by Escherichia coli. ENT-Fe complexes are imported across the outer membrane of P. aeruginosa by the two outer membrane transporters PfeA and PirA. Iron is released from ENT in the P. aeruginosa periplasm by hydrolysis of ENT by the esterase PfeE. We show here that pfeE gene deletion renders P. aeruginosa unable to grow in the presence of ENT because it is unable to access iron via this siderophore. Two-species co-cultures under iron-restricted conditions show that P. aeruginosa strongly represses the growth of E. coli as long it is able to produce its own siderophores. Both strains are present in similar proportions in the culture as long as the siderophore-deficient P. aeruginosa strain is able to use ENT produced by E. coli to access iron. If pfeE is deleted, E. coli has the upper hand in the culture and P. aeruginosa growth is repressed. Overall, these data show that PfeE is the Achilles' heel of P. aeruginosa in communities with bacteria producing ENT.
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Affiliation(s)
- Véronique Gasser
- InnoVec, UMR7242, Université de Strasbourg, ESBS, Bld Sébastien Brant, F-67413 Illkirch, France; (V.G.); (T.H.)
- UMR7242, CNRS, ESBS, Bld Sébastien Brant, F-67413 Illkirch, France
| | - Laurianne Kuhn
- Plateforme Proteomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg CEDEX, France; (L.K.); (P.H.)
| | - Thibaut Hubert
- InnoVec, UMR7242, Université de Strasbourg, ESBS, Bld Sébastien Brant, F-67413 Illkirch, France; (V.G.); (T.H.)
- UMR7242, CNRS, ESBS, Bld Sébastien Brant, F-67413 Illkirch, France
| | - Laurent Aussel
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie de la Méditerranée, Aix-Marseille University, CNRS, 13 900 Marseille, France;
| | - Philippe Hammann
- Plateforme Proteomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg CEDEX, France; (L.K.); (P.H.)
| | - Isabelle J. Schalk
- InnoVec, UMR7242, Université de Strasbourg, ESBS, Bld Sébastien Brant, F-67413 Illkirch, France; (V.G.); (T.H.)
- UMR7242, CNRS, ESBS, Bld Sébastien Brant, F-67413 Illkirch, France
- Correspondence:
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17
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Pierce EC, Morin M, Little JC, Liu RB, Tannous J, Keller NP, Pogliano K, Wolfe BE, Sanchez LM, Dutton RJ. Bacterial-fungal interactions revealed by genome-wide analysis of bacterial mutant fitness. Nat Microbiol 2021; 6:87-102. [PMID: 33139882 PMCID: PMC8515420 DOI: 10.1038/s41564-020-00800-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/16/2020] [Indexed: 11/09/2022]
Abstract
Microbial interactions are expected to be major determinants of microbiome structure and function. Although fungi are found in diverse microbiomes, their interactions with bacteria remain largely uncharacterized. In this work, we characterize interactions in 16 different bacterial-fungal pairs, examining the impacts of 8 different fungi isolated from cheese rind microbiomes on 2 bacteria (Escherichia coli and a cheese-isolated Pseudomonas psychrophila). Using random barcode transposon-site sequencing with an analysis pipeline that allows statistical comparisons between different conditions, we observed that fungal partners caused widespread changes in the fitness of bacterial mutants compared to growth alone. We found that all fungal species modulated the availability of iron and biotin to bacterial species, which suggests that these may be conserved drivers of bacterial-fungal interactions. Species-specific interactions were also uncovered, a subset of which suggested fungal antibiotic production. Changes in both conserved and species-specific interactions resulted from the deletion of a global regulator of fungal specialized metabolite production. This work highlights the potential for broad impacts of fungi on bacterial species within microbiomes.
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Affiliation(s)
- Emily C Pierce
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Manon Morin
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Jessica C Little
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - Roland B Liu
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Joanna Tannous
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Food Research Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Kit Pogliano
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | | | - Laura M Sanchez
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - Rachel J Dutton
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.
- Center for Microbiome Innovation, Jacobs School of Engineering, University of California, San Diego, La Jolla, CA, USA.
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18
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Normant V, Josts I, Kuhn L, Perraud Q, Fritsch S, Hammann P, Mislin GLA, Tidow H, Schalk IJ. Nocardamine-Dependent Iron Uptake in Pseudomonas aeruginosa: Exclusive Involvement of the FoxA Outer Membrane Transporter. ACS Chem Biol 2020; 15:2741-2751. [PMID: 32902248 DOI: 10.1021/acschembio.0c00535] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron is a key nutrient for almost all living organisms. Paradoxically, it is poorly soluble and consequently poorly bioavailable. Bacteria have thus developed multiple strategies to access this metal. One of the most common consists of the use of siderophores, small compounds that chelate ferric iron with very high affinity. Many bacteria are able to produce their own siderophores or use those produced by other microorganisms (exosiderophores) in a piracy strategy. Pseudomonas aeruginosa produces two siderophores, pyoverdine and pyochelin, and is also able to use a large panel of exosiderophores. We investigated the ability of P. aeruginosa to use nocardamine (NOCA) and ferrioxamine B (DFOB) as exosiderophores under iron-limited planktonic growth conditions. Proteomic and RT-qPCR approaches showed induction of the transcription and expression of the outer membrane transporter FoxA in the presence of NOCA or DFOB in the bacterial environment. Expression of the proteins of the heme- or pyoverdine- and pyochelin-dependent iron uptake pathways was not affected by the presence of these two tris-hydroxamate siderophores. 55Fe uptake assays using foxA mutants showed ferri-NOCA to be exclusively transported by FoxA, whereas ferri-DFOB was transported by FoxA and at least one other unidentified transporter. The crystal structure of FoxA complexed with NOCA-Fe revealed very similar siderophore binding sites between NOCA-Fe and DFOB-Fe. We discuss iron uptake by hydroxamate exosiderophores in P. aeruginosa cells in light of these results.
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Affiliation(s)
- Vincent Normant
- CNRS, UMR7242, ESBS, Université de Strasbourg, Bld Sébastien Brant, F-67412 Illkirch, France
| | - Inokentijs Josts
- The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Quentin Perraud
- CNRS, UMR7242, ESBS, Université de Strasbourg, Bld Sébastien Brant, F-67412 Illkirch, France
| | - Sarah Fritsch
- CNRS, UMR7242, ESBS, Université de Strasbourg, Bld Sébastien Brant, F-67412 Illkirch, France
| | - Philippe Hammann
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Gaëtan L. A. Mislin
- CNRS, UMR7242, ESBS, Université de Strasbourg, Bld Sébastien Brant, F-67412 Illkirch, France
| | - Henning Tidow
- The Hamburg Centre for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany
| | - Isabelle J. Schalk
- CNRS, UMR7242, ESBS, Université de Strasbourg, Bld Sébastien Brant, F-67412 Illkirch, France
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19
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Transcriptomic Study of Substrate-Specific Transport Mechanisms for Iron and Carbon in the Marine Copiotroph Alteromonas macleodii. mSystems 2020; 5:5/2/e00070-20. [PMID: 32345736 PMCID: PMC7190382 DOI: 10.1128/msystems.00070-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
As the major facilitators of the turnover of organic matter in the marine environment, the ability of heterotrophic bacteria to acquire specific compounds within the diverse range of dissolved organic matter will affect the regeneration of essential nutrients such as iron and carbon. TonB-dependent transporters are a prevalent cellular tool in Gram-negative bacteria that allow a relatively high-molecular-weight fraction of organic matter to be directly accessed. However, these transporters are not well characterized in marine bacteria, limiting our understanding of the flow of specific substrates through the marine microbial loop. Here, we characterize the TonB-dependent transporters responsible for iron and carbon acquisition in a representative marine copiotroph and examine their distribution across the genus Alteromonas. We provide evidence that substrate-specific bioavailability is niche specific, particularly for iron complexes, indicating that transport capacity may serve as a significant control on microbial community dynamics and the resultant cycling of organic matter. Iron is an essential micronutrient for all microbial growth in the marine environment, and in heterotrophic bacteria, iron is tightly linked to carbon metabolism due to its central role as a cofactor in enzymes of the respiratory chain. Here, we present the iron- and carbon-regulated transcriptomes of a representative marine copiotroph, Alteromonas macleodii ATCC 27126, and characterize its cellular transport mechanisms. ATCC 27126 has distinct metabolic responses to iron and carbon limitation and, accordingly, uses distinct sets of TonB-dependent transporters for the acquisition of iron and carbon. These distinct sets of TonB-dependent transporters were of a similar number, indicating that the diversity of carbon and iron substrates available to ATCC 27126 is of a similar scale. For the first time in a marine bacterium, we have also identified six characteristic inner membrane permeases for the transport of siderophores via an ATPase-independent mechanism. An examination of the distribution of specific TonB-dependent transporters in 31 genomes across the genus Alteromonas points to niche specialization in transport capacity, particularly for iron. We conclude that the substrate-specific bioavailability of both iron and carbon in the marine environment will likely be a key control on the processing of organic matter through the microbial loop. IMPORTANCE As the major facilitators of the turnover of organic matter in the marine environment, the ability of heterotrophic bacteria to acquire specific compounds within the diverse range of dissolved organic matter will affect the regeneration of essential nutrients such as iron and carbon. TonB-dependent transporters are a prevalent cellular tool in Gram-negative bacteria that allow a relatively high-molecular-weight fraction of organic matter to be directly accessed. However, these transporters are not well characterized in marine bacteria, limiting our understanding of the flow of specific substrates through the marine microbial loop. Here, we characterize the TonB-dependent transporters responsible for iron and carbon acquisition in a representative marine copiotroph and examine their distribution across the genus Alteromonas. We provide evidence that substrate-specific bioavailability is niche specific, particularly for iron complexes, indicating that transport capacity may serve as a significant control on microbial community dynamics and the resultant cycling of organic matter.
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20
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Perraud Q, Cantero P, Roche B, Gasser V, Normant VP, Kuhn L, Hammann P, Mislin GLA, Ehret-Sabatier L, Schalk IJ. Phenotypic Adaption of Pseudomonas aeruginosa by Hacking Siderophores Produced by Other Microorganisms. Mol Cell Proteomics 2020; 19:589-607. [PMID: 32024770 PMCID: PMC7124469 DOI: 10.1074/mcp.ra119.001829] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/23/2019] [Indexed: 12/31/2022] Open
Abstract
Bacteria secrete siderophores to access iron, a key nutrient poorly bioavailable and the source of strong competition between microorganisms in most biotopes. Many bacteria also use siderophores produced by other microorganisms (exosiderophores) in a piracy strategy. Pseudomonas aeruginosa, an opportunistic pathogen, produces two siderophores, pyoverdine and pyochelin, and is also able to use a panel of exosiderophores. We first investigated expression of the various iron-uptake pathways of P. aeruginosa in three different growth media using proteomic and RT-qPCR approaches and observed three different phenotypic patterns, indicating complex phenotypic plasticity in the expression of the various iron-uptake pathways. We then investigated the phenotypic plasticity of iron-uptake pathway expression in the presence of various exosiderophores (present individually or as a mixture) under planktonic growth conditions, as well as in an epithelial cell infection assay. In all growth conditions tested, catechol-type exosiderophores were clearly more efficient in inducing the expression of their corresponding transporters than the others, showing that bacteria opt for the use of catechol siderophores to access iron when they are present in the environment. In parallel, expression of the proteins of the pyochelin pathway was significantly repressed under most conditions tested, as well as that of proteins of the pyoverdine pathway, but to a lesser extent. There was no effect on the expression of the heme and ferrous uptake pathways. Overall, these data provide precise insights on how P. aeruginosa adjusts the expression of its various iron-uptake pathways (phenotypic plasticity and switching) to match varying levels of iron and competition.
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Affiliation(s)
- Quentin Perraud
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Paola Cantero
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Béatrice Roche
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Véronique Gasser
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Vincent P Normant
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Philippe Hammann
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, F-67084 Strasbourg Cedex, France
| | - Gaëtan L A Mislin
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Laurence Ehret-Sabatier
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Isabelle J Schalk
- Université de Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France; CNRS, UMR7242, ESBS, Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France.
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21
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Kurth C, Wasmuth I, Wichard T, Pohnert G, Nett M. Algae induce siderophore biosynthesis in the freshwater bacterium Cupriavidus necator H16. Biometals 2018; 32:77-88. [PMID: 30474772 DOI: 10.1007/s10534-018-0159-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/20/2018] [Indexed: 12/20/2022]
Abstract
Cupriachelin is a photoreactive lipopeptide siderophore produced by the freshwater bacterium Cupriavidus necator H16. In the presence of sunlight, the iron-loaded siderophore undergoes photolytic cleavage, thereby releasing solubilized iron into the environment. This iron is not only available to the siderophore producer, but also to the surrounding microbial community. In this study, the cupriachelin-based interaction between C. necator H16 and the freshwater diatom Navicula pelliculosa was investigated. A reporter strain of the bacterium was constructed to study differential expression levels of the cupriachelin biosynthesis gene cucJ in response to varying environmental conditions. Not only iron starvation, but also culture supernatants of N. pelliculosa were found to induce cupriachelin biosynthesis. The transcription factors involved in this differential gene expression were identified using DNA-protein pulldown assays. Besides the well-characterized ferric uptake regulator, a two-component system was found to tune the expression of cupriachelin biosynthesis genes in the presence of diatom supernatants.
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Affiliation(s)
- Colette Kurth
- Leibniz Institute for Natural Product Research and Infection Biology, Hans Knöll Institute, Beutenbergstr. 11a, 07745, Jena, Germany
| | - Ina Wasmuth
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstrasse 8, 07743, Jena, Germany
| | - Thomas Wichard
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstrasse 8, 07743, Jena, Germany
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Lessingstrasse 8, 07743, Jena, Germany
| | - Markus Nett
- Laboratory of Technical Biology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany.
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22
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Perraud Q, Moynié L, Gasser V, Munier M, Godet J, Hoegy F, Mély Y, Mislin GLA, Naismith JH, Schalk IJ. A Key Role for the Periplasmic PfeE Esterase in Iron Acquisition via the Siderophore Enterobactin in Pseudomonas aeruginosa. ACS Chem Biol 2018; 13:2603-2614. [PMID: 30086222 DOI: 10.1021/acschembio.8b00543] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Enterobactin (ENT) is a siderophore (iron-chelating compound) produced by Escherichia coli to gain access to iron, an indispensable nutrient for bacterial growth. ENT is used as an exosiderophore by Pseudomonas aeruginosa with transport of ferri-ENT across the outer membrane by the PfeA transporter. Next to the pfeA gene on the chromosome is localized a gene encoding for an esterase, PfeE, whose transcription is regulated, as for pfeA, by the presence of ENT in bacterial environment. Purified PfeE hydrolyzed ferri-ENT into three molecules of 2,3-DHBS (2,3-dihydroxybenzoylserine) still complexed with ferric iron, and complete dissociation of iron from ENT chelating groups was only possible in the presence of both PfeE and an iron reducer, such as DTT. The crystal structure of PfeE and an inactive PfeE mutant complexed with ferri-ENT or a nonhydrolyzable ferri-catechol complex allowed identification of the enzyme binding site and the catalytic triad. Finally, cell fractionation and fluorescence microscopy showed periplasmic localization of PfeE in P. aeruginosa cells. Thus, the molecular mechanism of iron dissociation from ENT in P. aeruginosa differs from that previously described in E. coli. In P. aeruginosa, siderophore hydrolysis occurs in the periplasm, with ENT never reaching the bacterial cytoplasm. In E. coli, ferri-ENT crosses the inner membrane via the ABC transporter FepBCD and ferri-ENT is hydrolyzed by the esterase Fes only once it is in the cytoplasm.
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Affiliation(s)
- Quentin Perraud
- Université de Strasbourg, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
- CNRS, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Lucile Moynié
- Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
- Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7BN, United Kingdom
| | - Véronique Gasser
- Université de Strasbourg, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
- CNRS, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Mathilde Munier
- Université de Strasbourg, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
- CNRS, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Julien Godet
- Université de Strasbourg, Laboratoire de BioImagerie et Pathologies, UMR CNRS 7021, F-67413 Illkirch, Strasbourg, France
| | - Françoise Hoegy
- Université de Strasbourg, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
- CNRS, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - Yves Mély
- Université de Strasbourg, Laboratoire de BioImagerie et Pathologies, UMR CNRS 7021, F-67413 Illkirch, Strasbourg, France
| | - Gaëtan. L. A. Mislin
- Université de Strasbourg, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
- CNRS, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
| | - James H. Naismith
- Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, United Kingdom
- Research Complex at Harwell, Didcot OX11 0FA, United Kingdom
- Division of Structural Biology, University of Oxford, Roosevelt Drive, Headington, Oxford OX3 7BN, United Kingdom
| | - Isabelle J. Schalk
- Université de Strasbourg, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
- CNRS, UMR7242, ESBS, 300 Bld Sébastien Brant, F-67413 Illkirch, Strasbourg, France
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23
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Synthetic biology for microbial heavy metal biosensors. Anal Bioanal Chem 2017; 410:1191-1203. [DOI: 10.1007/s00216-017-0751-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 10/23/2017] [Accepted: 11/07/2017] [Indexed: 11/26/2022]
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24
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Paulen A, Hoegy F, Roche B, Schalk IJ, Mislin GL. Synthesis of conjugates between oxazolidinone antibiotics and a pyochelin analogue. Bioorg Med Chem Lett 2017; 27:4867-4870. [DOI: 10.1016/j.bmcl.2017.09.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/15/2017] [Accepted: 09/16/2017] [Indexed: 10/18/2022]
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25
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Ravikumar S, Baylon MG, Park SJ, Choi JI. Engineered microbial biosensors based on bacterial two-component systems as synthetic biotechnology platforms in bioremediation and biorefinery. Microb Cell Fact 2017; 16:62. [PMID: 28410609 PMCID: PMC5391612 DOI: 10.1186/s12934-017-0675-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 04/04/2017] [Indexed: 12/30/2022] Open
Abstract
Two-component regulatory systems (TCRSs) mediate cellular response by coupling sensing and regulatory mechanisms. TCRSs are comprised of a histidine kinase (HK), which serves as a sensor, and a response regulator, which regulates expression of the effector gene after being phosphorylated by HK. Using these attributes, bacterial TCRSs can be engineered to design microbial systems for different applications. This review focuses on the current advances in TCRS-based biosensors and on the design of microbial systems for bioremediation and their potential application in biorefinery.
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Affiliation(s)
- Sambandam Ravikumar
- Biomolecules Engineering Lab, Department of Biotechnology and Bioengineering, Chonnam National University, 77 Yongbong-ro, Gwangju, 61186, Republic of Korea
| | - Mary Grace Baylon
- Division of Chemical Engineering and Materials Science, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul, 03760, Republic of Korea
| | - Si Jae Park
- Division of Chemical Engineering and Materials Science, Ewha Womans University, 52 Ewhayeodae-gil, Seodaemun-gu, Seoul, 03760, Republic of Korea.
| | - Jong-Il Choi
- Biomolecules Engineering Lab, Department of Biotechnology and Bioengineering, Chonnam National University, 77 Yongbong-ro, Gwangju, 61186, Republic of Korea.
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26
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Schalk IJ, Cunrath O. An overview of the biological metal uptake pathways in Pseudomonas aeruginosa. Environ Microbiol 2016; 18:3227-3246. [PMID: 27632589 DOI: 10.1111/1462-2920.13525] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 09/07/2016] [Indexed: 12/21/2022]
Abstract
Biological metal ions, including Co, Cu, Fe, Mg, Mn, Mo, Ni and Zn ions, are necessary for the survival and the growth of all microorganisms. Their biological functions are linked to their particular chemical properties: they play a role in structuring macromolecules and/or act as co-factors catalyzing diverse biochemical reactions. These metal ions are also essential for microbial pathogens during infection: they are involved in bacterial metabolism and various virulence factor functions. Therefore, during infection, bacteria need to acquire biological metal ions from the host such that there is competition for these ions between the bacterium and the host. Evidence is increasingly emerging of "nutritional immunity" against pathogens in the hosts; this includes strategies making access to metals difficult for infecting bacteria. It is clear that biological metals play key roles during infection and in the battle between the pathogens and the host. Here, we summarize current knowledge about the strategies used by Pseudomonas aeruginosa to access the various biological metals it requires. P. aeruginosa is a medically significant Gram-negative bacterial opportunistic pathogen that can cause severe chronic lung infections in cystic fibrosis patients and that is responsible for nosocomial infections worldwide.
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Affiliation(s)
- Isabelle J Schalk
- UMR 7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brant, F-67413, Illkirch, Strasbourg, France.
| | - Olivier Cunrath
- UMR 7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brant, F-67413, Illkirch, Strasbourg, France
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27
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Gasser V, Baco E, Cunrath O, August PS, Perraud Q, Zill N, Schleberger C, Schmidt A, Paulen A, Bumann D, Mislin GLA, Schalk IJ. Catechol siderophores repress the pyochelin pathway and activate the enterobactin pathway in Pseudomonas aeruginosa: an opportunity for siderophore-antibiotic conjugates development. Environ Microbiol 2016; 18:819-32. [PMID: 26718479 DOI: 10.1111/1462-2920.13199] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 12/20/2015] [Accepted: 12/23/2015] [Indexed: 01/08/2023]
Abstract
Previous studies have suggested that antibiotic vectorization by siderophores (iron chelators produced by bacteria) considerably increases the efficacy of such drugs. The siderophore serves as a vector: when the pathogen tries to take up iron via the siderophore, it also takes up the antibiotic. Catecholates are among the most common iron-chelating compounds used in synthetic siderophore-antibiotic conjugates. Using reverse transcription polymerase chain reaction and proteomic approaches, we showed that the presence of catecholate compounds in the medium of Pseudomonas aeruginosa led to strong activation of the transcription and expression of the outer membrane transporter PfeA, the ferri-enterobactin importer. Iron-55 uptake assays on bacteria with and without PfeA expression confirmed that catechol compounds imported iron into P. aeruginosa cells via PfeA. Uptake rates were between 0.3 × 10(3) and 2 × 10(3) Fe atoms/bacterium/min according to the used catechol siderophore in iron-restricted medium, and remained as high as 0.8 × 10(3) Fe atoms/bacterium/min for enterobactin, even in iron-rich medium. Reverse transcription polymerase chain reaction and proteomic approaches showed that in parallel to this switching on of PfeA expression, a repression of the expression of pyochelin (PCH) pathway genes (PCH being one of the two siderophores produced by P. aeruginosa for iron acquisition) was observed.
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Affiliation(s)
- Véronique Gasser
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | - Etienne Baco
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | - Olivier Cunrath
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | - Pamela Saint August
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Quentin Perraud
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | - Nicolas Zill
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | | | - Alexander Schmidt
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Aurélie Paulen
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | - Dirk Bumann
- Focal Area Infection Biology, Biozentrum, University of Basel, Basel, Switzerland
| | - Gaëtan L A Mislin
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
| | - Isabelle J Schalk
- Université de Strasbourg, ESBS, F-67413, Illkirch, France.,UMR 7242, CNRS, F-67413, Illkirch, France
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28
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Tanabe T, Kato A, Shiuchi K, Miyamoto K, Tsujibo H, Maki J, Yamamoto S, Funahashi T. Regulation of the expression of the Vibrio parahaemolyticus peuA gene encoding an alternative ferric enterobactin receptor. PLoS One 2014; 9:e105749. [PMID: 25148374 PMCID: PMC4141801 DOI: 10.1371/journal.pone.0105749] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 07/27/2014] [Indexed: 11/18/2022] Open
Abstract
A pvsB-vctA-irgA triple deletion mutant of Vibrio parahaemolyticus can utilize enterobactin under iron-limiting conditions by inducing a previously undescribed receptor, PeuA (VPA0150), in response to extracellular alkaline pH and enterobactin. In silico analyses revealed the existence of a two-component regulatory system operon, peuRS, immediately upstream of peuA, which constitutes an operon with the TonB2 system genes. Both the peuRS and peuA-tonB2 operons were found to be upregulated under iron-limiting conditions in a ferric uptake regulator (Fur)-dependent manner. The involvement of peuA and peuRS in enterobactin utilization was analyzed by complementation experiments using deletion mutants. Primer extension analysis indicated that, under iron-limiting conditions, the transcription of peuA was initiated from the +1 site at pH 7.0 and from both the +1 and +39 sites at pH 8.0 in the presence of enterobactin. The +39 transcript was absent from the peuRS deletion mutant. Secondary structure prediction of their 5′-untranslated regions suggested that translation initiation is blocked in the +1 transcript, but not in the +39 transcript. Consistent with this, in vitro translation analysis demonstrated that production of PeuA was determined only by the +39 transcript. These studies establish a novel gene regulation mechanism in which the two-component regulatory system PeuRS enhances expression of the alternative +39 transcript that possesses non-inhibitory structure, allowing the peuA expression to be regulated at the translation stage.
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Affiliation(s)
- Tomotaka Tanabe
- Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan
- * E-mail:
| | - Ayaka Kato
- Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan
| | - Keiichi Shiuchi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Katsushiro Miyamoto
- Department of Microbiology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan
| | - Hiroshi Tsujibo
- Department of Microbiology, Osaka University of Pharmaceutical Sciences, Takatsuki, Osaka, Japan
| | - Jun Maki
- Laboratory of Infectious Diseases, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan
| | - Shigeo Yamamoto
- Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan
| | - Tatsuya Funahashi
- Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime, Japan
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29
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Synthesis and antibacterial activity of catecholate–ciprofloxacin conjugates. Bioorg Med Chem 2014; 22:4049-60. [DOI: 10.1016/j.bmc.2014.05.067] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/09/2014] [Accepted: 05/29/2014] [Indexed: 01/07/2023]
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30
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Mislin GLA, Schalk IJ. Siderophore-dependent iron uptake systems as gates for antibiotic Trojan horse strategies against Pseudomonas aeruginosa. Metallomics 2014; 6:408-20. [PMID: 24481292 DOI: 10.1039/c3mt00359k] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen responsible for nosocomial infections. The prevalence of antibiotic-resistant P. aeruginosa strains is increasing, necessitating the urgent development of new strategies to improve the control of this pathogen. Its bacterial envelope constitutes of an outer and an inner membrane enclosing the periplasm. This structure plays a key role in the resistance of the pathogen, by decreasing the penetration and the biological impact of many antibiotics. However, this barrier may also be seen as the "Achilles heel" of the bacterium as some of its functions provide opportunities for breaching bacterial defenses. Siderophore-dependent iron uptake systems act as gates in the bacterial envelope and could be used in a "Trojan horse" strategy, in which the conjugation of an antibiotic to a siderophore could significantly increase the biological activity of the antibiotic, by enhancing its transport into the bacterium. In this review, we provide an overview of the various siderophore-antibiotic conjugates that have been developed for use against P. aeruginosa and show that an accurate knowledge of the structural and functional features of the proteins involved in this transmembrane transport is required for the design and synthesis of effective siderophore-antibiotic Trojan horse conjugates.
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Affiliation(s)
- Gaëtan L A Mislin
- UMR 7242, Université de Strasbourg-CNRS, ESBS, 300 Boulevard, Sébastien Brant, F-67413 Illkirch, Strasbourg, France.
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31
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Nader M, Journet L, Meksem A, Guillon L, Schalk IJ. Mechanism of Ferripyoverdine Uptake by Pseudomonas aeruginosa Outer Membrane Transporter FpvA: No Diffusion Channel Formed at Any Time during Ferrisiderophore Uptake. Biochemistry 2011; 50:2530-40. [DOI: 10.1021/bi101821n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mirella Nader
- UMR7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brandt, F-67513 Illkirch, France
| | - Laure Journet
- UMR7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brandt, F-67513 Illkirch, France
| | - Ahmed Meksem
- UMR7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brandt, F-67513 Illkirch, France
| | - Laurent Guillon
- UMR7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brandt, F-67513 Illkirch, France
| | - Isabelle J. Schalk
- UMR7242, Université de Strasbourg-CNRS, ESBS, Blvd Sébastien Brandt, F-67513 Illkirch, France
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32
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Hartney SL, Mazurier S, Kidarsa TA, Quecine MC, Lemanceau P, Loper JE. TonB-dependent outer-membrane proteins and siderophore utilization in Pseudomonas fluorescens Pf-5. Biometals 2010; 24:193-213. [PMID: 21080032 DOI: 10.1007/s10534-010-9385-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 10/16/2010] [Indexed: 12/30/2022]
Abstract
The soil bacterium Pseudomonas fluorescens Pf-5 produces two siderophores, a pyoverdine and enantio-pyochelin, and its proteome includes 45 TonB-dependent outer-membrane proteins, which commonly function in uptake of siderophores and other substrates from the environment. The 45 proteins share the conserved β-barrel and plug domains of TonB-dependent proteins but only 18 of them have an N-terminal signaling domain characteristic of TonB-dependent transducers (TBDTs), which participate in cell-surface signaling systems. Phylogenetic analyses of the 18 TBDTs and 27 TonB-dependent receptors (TBDRs), which lack the N-terminal signaling domain, suggest a complex evolutionary history including horizontal transfer among different microbial lineages. Putative functions were assigned to certain TBDRs and TBDTs in clades including well-characterized orthologs from other Pseudomonas spp. A mutant of Pf-5 with deletions in pyoverdine and enantio-pyochelin biosynthesis genes was constructed and characterized for iron-limited growth and utilization of a spectrum of siderophores. The mutant could utilize as iron sources a large number of pyoverdines with diverse structures as well as ferric citrate, heme, and the siderophores ferrichrome, ferrioxamine B, enterobactin, and aerobactin. The diversity and complexity of the TBDTs and TBDRs with roles in iron uptake clearly indicate the importance of iron in the fitness and survival of Pf-5 in the environment.
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Affiliation(s)
- Sierra L Hartney
- Department of Botany and Plant Pathology, Oregon State University, 2082 Cordley Hall, Corvallis, OR 97331, USA
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33
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Cornelis P, Matthijs S, Van Oeffelen L. Iron uptake regulation in Pseudomonas aeruginosa. Biometals 2009; 22:15-22. [PMID: 19130263 DOI: 10.1007/s10534-008-9193-0] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Accepted: 12/07/2008] [Indexed: 01/18/2023]
Abstract
The Pseudomonas genus belongs to the gamma division of Proteobacteria and many species produce the characteristic yellow-green siderophore pyoverdine, and often a second siderophore, of lower affinity for iron. These bacteria are known for their ability to colonize different ecological niches and for their versatile metabolism. It is therefore not surprising that they are endowed with the capacity to take up exogenous xenosiderophores via different TonB-dependent receptors. Uptake of iron is controlled by the central regulator Fur, and via extracytoplasmic sigma factors or other types of regulators (two-component systems, AraC regulators). In this review the Fur regulon (experimentally proven and/or predicted) of P. aeruginosa will be presented. An interesting feature revealed by this analysis of Fur-regulated genes is the overlap between the iron and the sulfur regulons as well with the quorum sensing system.
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Affiliation(s)
- Pierre Cornelis
- Department of Molecular and Cellular Interactions, Laboratory of Microbial Interactions, Flanders Interuniversity Institute for Biotechnology, Vrije Universiteit Brussel, Brussels, Belgium.
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34
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Michel L, Bachelard A, Reimmann C. Ferripyochelin uptake genes are involved in pyochelin-mediated signalling in Pseudomonas aeruginosa. MICROBIOLOGY-SGM 2007; 153:1508-1518. [PMID: 17464065 DOI: 10.1099/mic.0.2006/002915-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In response to iron starvation, Pseudomonas aeruginosa produces the siderophore pyochelin. When secreted to the extracellular environment, pyochelin chelates iron and transports it to the bacterial cytoplasm via its specific outer-membrane receptor FptA and the inner-membrane permease FptX. Exogenously added pyochelin also acts as a signal which induces the expression of the pyochelin biosynthesis and uptake genes by activating PchR, a cytoplasmic regulatory protein of the AraC/XylS family. The importance of ferripyochelin uptake genes in this regulation was evaluated. The fptA and fptX genes were shown to be part of the fptABCX ferripyochelin transport operon, which is conserved in Burkholderia sp. and Rhodospirillum rubrum. The fptB and fptC genes were found to be dispensable for utilization of pyochelin as an iron source, for signalling and for pyochelin production. By contrast, mutations in fptA and fptX not only interfered with pyochelin utilization, but also affected signalling and diminished siderophore production. It is concluded from this that pyochelin-mediated signalling operates to a large extent via the ferripyochelin transport system.
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Affiliation(s)
- Laurent Michel
- Département de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland
| | - Aude Bachelard
- Département de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland
| | - Cornelia Reimmann
- Département de Microbiologie Fondamentale, Université de Lausanne, CH-1015 Lausanne, Switzerland
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Greenwald J, Hoegy F, Nader M, Journet L, Mislin GLA, Graumann PL, Schalk IJ. Real Time Fluorescent Resonance Energy Transfer Visualization of Ferric Pyoverdine Uptake in Pseudomonas aeruginosa. J Biol Chem 2007; 282:2987-95. [PMID: 17148441 DOI: 10.1074/jbc.m609238200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To acquire iron, Pseudomonas aeruginosa secretes a major fluorescent siderophore, pyoverdine (PvdI), that chelates iron and shuttles it into the cells via the specific outer membrane transporter, FpvAI. We took advantage of the fluorescence properties of PvdI and its metal chelates as well as the efficient FRET between donor tryptophans in FpvAI and PvdI to follow the fate of the siderophore during iron uptake. Our findings with PvdI-Ga and PvdI-Cr uptake indicate that iron reduction is required for the dissociation of PvdI-Fe, that a ligand exchange for iron occurs, and that this dissociation occurs in the periplasm. We also observed a delay between PvdI-Fe dissociation and the rebinding of PvdI to FpvAI, underlining the kinetic independence of metal release and siderophore recycling. Meanwhile, PvdI is not modified but recycled to the medium, still competent for iron chelation and transport. Finally, in vivo fluorescence microscopy revealed patches of PvdI, suggesting that uptake occurs via macromolecular assemblies on the cell surface.
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Affiliation(s)
- Jason Greenwald
- Métaux et Microorganismes: Chimie, Biologie, et Applications, UMR 7175-LC1 Institut Gilbert-Laustriat, CNRS-Université Louis Pasteur, ESBS, Boulevard Sébastien Brant, F-67413 Illkirch, Strasbourg, France
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Morales SE, Lewis TA. Transcriptional regulation of the pdt gene cluster of Pseudomonas stutzeri KC involves an AraC/XylS family transcriptional activator (PdtC) and the cognate siderophore pyridine-2,6-bis(thiocarboxylic acid). Appl Environ Microbiol 2006; 72:6994-7002. [PMID: 16936044 PMCID: PMC1636214 DOI: 10.1128/aem.01518-06] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to gain an understanding of the molecular mechanisms dictating production of the siderophore and dechlorination agent pyridine-2,6-bis(thiocarboxylic acid) (PDTC), we have begun characterization of a gene found in the pdt gene cluster of Pseudomonas stutzeri KC predicted to have a regulatory role. That gene product is an AraC family transcriptional activator, PdtC. Quantitative reverse transcription-PCR and expression of transcriptional reporter fusions were used to assess a role for pdtC in the transcription of pdt genes. PdtC and an upstream, promoter-proximal DNA segment were required for wild-type levels of expression from the promoter of a predicted biosynthesis operon (P(pdtF)). At least two other transcriptional units within the pdt cluster were also dependent upon pdtC for expression at wild-type levels. The use of a heterologous, Pseudomonas putida host demonstrated that pdtC and an exogenously added siderophore were necessary and sufficient for expression from the pdtF promoter, i.e., none of the PDTC utilization genes within the pdt cluster were required for transcriptional signaling. Tests using the promoter of the pdtC gene in transcriptional reporter fusions indicated siderophore-dependent negative autoregulation similar to that seen with other AraC-type regulators of siderophore biosynthesis and utilization genes. The data increase the repertoire of siderophore systems known to be regulated by this type of transcriptional activator and have implications for PDTC signaling.
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Affiliation(s)
- Sergio E Morales
- Department of Microbiology and Molecular Genetics, University of Vermont, 95 Carrigan Dr., Burlington, VT 05405, USA
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Anderson MT, Armstrong SK. The Bordetella bfe system: growth and transcriptional response to siderophores, catechols, and neuroendocrine catecholamines. J Bacteriol 2006; 188:5731-40. [PMID: 16885441 PMCID: PMC1540089 DOI: 10.1128/jb.00495-06] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Accepted: 05/30/2006] [Indexed: 11/20/2022] Open
Abstract
Ferric enterobactin utilization by Bordetella bronchiseptica and Bordetella pertussis requires the BfeA outer membrane receptor. Under iron-depleted growth conditions, transcription of bfeA is activated by the BfeR regulator by a mechanism requiring the siderophore enterobactin. In this study, enterobactin-inducible bfeA transcription was shown to be TonB independent. To determine whether other siderophores or nonsiderophore catechols could be utilized by the Bfe system, various compounds were tested for the abilities to promote the growth of iron-starved B. bronchiseptica and induce bfeA transcription. The BfeA receptor transported ferric salmochelin, corynebactin, and the synthetic siderophores TRENCAM and MECAM. Salmochelin and MECAM induced bfeA transcription in iron-starved Bordetella cells, but induction by corynebactin and TRENCAM was minimal. The neuroendocrine catecholamines epinephrine, norepinephrine, and dopamine exhibited a remarkable capacity to induce transcription of bfeA. Norepinephrine treatment of B. bronchiseptica resulted in BfeR-dependent bfeA transcription, elevated BfeA receptor production, and growth stimulation. Pyrocatechol, carbidopa, and isoproterenol were similarly strong inducers of bfeA transcription, whereas tyramine and 3,4-dihydroxymandelic acid demonstrated low inducing activity. The results indicate that the inducer structure requires a catechol group for function and that the ability to induce bfeA transcription does not necessarily correlate with the ability to stimulate bacterial growth. The expanded range of catechol siderophores transported by the BfeA receptor demonstrates the potential versatility of the Bordetella Bfe iron retrieval system. The finding that catecholamine neurotransmitters activate bfeA transcription and promote growth suggests that Bordetella cells can perceive and may benefit from neuroendocrine catecholamines on the respiratory epithelium.
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Affiliation(s)
- Mark T Anderson
- Department of Microbiology, University of Minnesota, MMC 196, 420 Delaware Street S.E., Minneapolis, MN 55455-0312, USA
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Voulhoux R, Filloux A, Schalk IJ. Pyoverdine-mediated iron uptake in Pseudomonas aeruginosa: the Tat system is required for PvdN but not for FpvA transport. J Bacteriol 2006; 188:3317-23. [PMID: 16621825 PMCID: PMC1447448 DOI: 10.1128/jb.188.9.3317-3323.2006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Under iron-limiting conditions, Pseudomonas aeruginosa PAO1 secretes a fluorescent siderophore called pyoverdine (Pvd). After chelating iron, this ferric siderophore is transported back into the cells via the outer membrane receptor FpvA. The Pvd-dependent iron uptake pathway requires several essential genes involved in both the synthesis of Pvd and the uptake of ferric Pvd inside the cell. A previous study describing the global phenotype of a tat-deficient P. aeruginosa strain showed that the defect in Pvd-mediated iron uptake was due to the Tat-dependent export of proteins involved in Pvd biogenesis and ferric Pvd uptake (U. Ochsner, A. Snyder, A. I. Vasil, and M. L. Vasil, Proc. Natl. Acad. Sci. USA 99:8312-8317, 2002). Using biochemical and biophysical tools, we showed that despite its predicted Tat signal sequence, FpvA is correctly located in the outer membrane of a tat mutant and is fully functional for all steps of the iron uptake process (ferric Pvd uptake and recycling of Pvd on FpvA after iron release). However, in the tat mutant, no Pvd was produced. This suggested that a key element in the Pvd biogenesis pathway must be exported to the periplasm by the Tat pathway. We located PvdN, a still unknown but essential component in Pvd biogenesis, at the periplasmic side of the cytoplasmic membrane and showed that its export is Tat dependent. Our results further support the idea that a critical step of the Pvd biogenesis pathway involving PvdN occurs at the periplasmic side of the cytoplasmic membrane.
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Fischbach MA, Lin H, Liu DR, Walsh CT. How pathogenic bacteria evade mammalian sabotage in the battle for iron. Nat Chem Biol 2006; 2:132-8. [PMID: 16485005 DOI: 10.1038/nchembio771] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many bacteria, including numerous human pathogens, synthesize small molecules known as siderophores to scavenge iron. Enterobactin, a siderophore produced by enteric bacteria, is surprisingly ineffective as an iron-scavenging agent for bacteria growing in animals because of its hydrophobicity and its sequestration by the mammalian protein siderocalin, a component of the innate immune system. However, pathogenic strains of Escherichia coli and Salmonella use enzymes encoded by the iroA gene cluster to tailor enterobactin by glycosylation and linearization. The resulting modified forms of enterobactin, known as salmochelins, can evade siderocalin and are less hydrophobic than enterobactin, restoring this siderophore's iron-scavenging ability in mammals.
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Affiliation(s)
- Michael A Fischbach
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, USA
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Zhu M, Valdebenito M, Winkelmann G, Hantke K. Functions of the siderophore esterases IroD and IroE in iron-salmochelin utilization. Microbiology (Reading) 2005; 151:2363-2372. [PMID: 16000726 DOI: 10.1099/mic.0.27888-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The siderophore salmochelin is produced under iron-poor conditions bySalmonellaand many uropathogenicEscherichia colistrains. The production of salmochelin, a C-glucosylated enterobactin, is dependent on the synthesis of enterobactin and theiroBCDENgene cluster. AnE. coliIroD protein with an N-terminal His-tag cleaved cyclic salmochelin S4 to the linear trimer salmochelin S2, the dimer salmochelin S1, and the monomers dihydroxybenzoylserine and C-glucosylated dihydroxybenzoylserine (salmochelin SX, pacifarinic acid). The periplasmic IroE protein was purified as a MalE–IroE fusion protein. This enzyme degraded salmochelin S4 and ferric-salmochelin S4 to salmochelin S2 and ferric-salmochelin S2, respectively. InE. coli, uptake of ferric-salmochelin S4 was dependent on the cleavage by IroE, and independent of the FepBDGC ABC transporter in the cytoplasmic membrane. IroC, which has similarities to ABC-multidrug-resistance proteins, was necessary for the uptake of salmochelin S2 from the periplasm into the cytoplasm. IroE did not function as a classical binding protein since salmochelin S2 was taken up in the absence of a functional IroE protein. IroC mediated the uptake of iron via enterobactin in afepBmutant. IroE was also necessary in this case for the uptake of ferric-enterobactin, which indicated that only the linear degradation products of enterobactin were taken up via IroC. PfeE, thePseudomonas aeruginosaIroE homologue, was cloned, and its enzymic activity was shown to be very similar to that of IroE. It is suggested that homologues in other bacteria are also periplasmic IroE-type esterases of siderophores.
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Affiliation(s)
- Mingang Zhu
- Mikrobiologie/Membranphysiologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
| | - Marianne Valdebenito
- Mikrobiologie/Biotechnologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
| | - Günther Winkelmann
- Mikrobiologie/Biotechnologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
| | - Klaus Hantke
- Mikrobiologie/Membranphysiologie, Universität Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany
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Zolfaghar I, Angus AA, Kang PJ, To A, Evans DJ, Fleiszig SMJ. Mutation of retS, encoding a putative hybrid two-component regulatory protein in Pseudomonas aeruginosa, attenuates multiple virulence mechanisms. Microbes Infect 2005; 7:1305-16. [PMID: 16027020 DOI: 10.1016/j.micinf.2005.04.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2004] [Revised: 04/21/2005] [Accepted: 04/25/2005] [Indexed: 10/25/2022]
Abstract
Two-component regulatory systems play an important role in bacterial virulence. We report that mutation of a Pseudomonas aeruginosa gene designated retS (previously designated fimK; accession number PA4856) encoding a putative hybrid two-component regulator, attenuates multiple virulence mechanisms. The retS mutant was selected from a Tn5 transposon library of the cytotoxic P. aeruginosa strain PA103 based upon expression of a small-colony phenotype suggestive of reduced surface-associated "twitching" motility, a property dependent upon type IV pili. Subsequent analysis revealed that the mutant expressed pilin, albeit at lower levels than wild-type PA103. In a murine model of corneal infection, retS mutation was associated with delayed disease development and altered pathology. In vitro, retS mutants demonstrated loss of acute cytotoxic activity towards corneal epithelia as determined by trypan blue exclusion and by LDH release assays (P<0.0001). This coincided with loss of ExsA-regulated type III secretion. Mutation of retS also impaired ExsA-independent pathogenic mechanisms. When compared to the exsA mutant of PA103, retS mutants exhibited reduced epithelial adherence and invasion and reduced intracellular survival within the cells after invasion. Time-lapse video microscopy revealed that retS mutants, compared to exsA mutants, had a reduced capacity to access, and move along, the basal cell surfaces of corneal epithelial cell monolayers. Taken together, these data suggest that the protein encoded by retS regulates various properties of P. aeruginosa including both ExsA-dependent and ExsA-independent virulence mechanisms.
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Affiliation(s)
- Irandokht Zolfaghar
- School of Optometry, 688 Minor Hall, University of California, Berkeley, CA 94720-2020, USA
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42
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Anderson MT, Armstrong SK. The BfeR regulator mediates enterobactin-inducible expression of Bordetella enterobactin utilization genes. J Bacteriol 2004; 186:7302-11. [PMID: 15489442 PMCID: PMC523226 DOI: 10.1128/jb.186.21.7302-7311.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Accepted: 08/10/2004] [Indexed: 11/20/2022] Open
Abstract
Utilization of the enterobactin siderophore by the respiratory pathogens Bordetella pertussis and Bordetella bronchiseptica is dependent on the BfeA outer membrane receptor. This study determined that production of BfeA was increased significantly in iron-starved bacteria upon supplementation of cultures with enterobactin. A 1.01-kb open reading frame, designated bfeR, encoding a predicted positive transcriptional regulator of the AraC family was identified upstream and divergently oriented from bfeA. In iron-depleted cultures containing enterobactin, a Bordetella bfeR mutant exhibited markedly decreased BfeA receptor production compared to that of the wild-type strain. Additionally, B. pertussis and B. bronchiseptica bfeR mutants exhibited impaired growth with ferric enterobactin as the sole source of iron, demonstrating that effective enterobactin utilization is bfeR dependent. Transcriptional analysis using bfeA-lacZ reporter fusions in wild-type strains demonstrated that bfeA transcription was stimulated in iron-depleted conditions in the presence of enterobactin, compared to modest expression levels in cultures lacking enterobactin. In contrast, bfeA transcription in B. pertussis and B. bronchiseptica bfeR mutants was completely unresponsive to the enterobactin inducer. bfeA transcriptional analyses of a bfeA mutant demonstrated that induction by enterobactin did not require BfeA receptor-mediated uptake of the siderophore. These studies establish that bfeR encodes an enterobactin-dependent positive regulator of bfeA transcription in these Bordetella species.
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Affiliation(s)
- Mark T Anderson
- Department of Microbiology, University of Minnesota, MMC 196, 420 Delaware Street S.E., Minneapolis, MN 55455-0312, USA
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Vanderpool CK, Armstrong SK. Integration of environmental signals controls expression of Bordetella heme utilization genes. J Bacteriol 2004; 186:938-48. [PMID: 14761988 PMCID: PMC344224 DOI: 10.1128/jb.186.4.938-948.2004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Bordetella pertussis heme utilization gene cluster hurIR bhuRSTUV encodes regulatory and transport functions required for assimilation of iron from heme and hemoproteins. Expression of the bhu genes is iron regulated and heme inducible. The putative extracytoplasmic function (ECF) sigma factor, HurI, is required for heme-responsive bhu gene expression. In this study, transcriptional activation of B. pertussis bhu genes in response to heme compounds was shown to be dose dependent and specific for heme; protoporphyrin IX and other heme structural analogs did not activate bhu gene expression. Two promoters controlling expression of the heme utilization genes were mapped by primer extension analysis. The hurI promoter showed similarity to sigma(70)-like promoters, and its transcriptional activity was iron regulated and heme independent. A second promoter identified upstream of bhuR exhibited little similarity to previously characterized ECF sigma factor-dependent promoters. Expression of bhuR was iron regulated, heme responsive, and hurI dependent in B. pertussis, as shown in a previous study with Bordetella bronchiseptica. Further analyses showed that transcription originating at a distal upstream site and reading through the hurR-bhuR intergenic region contributes to bhuR expression under iron starvation conditions in the absence of heme inducer. The pattern of regulation of the readthrough transcript was consistent with transcription from the hurI promoter. The positions and regulation of the two promoters within the hur-bhu gene cluster influence the production of heme transport machinery so that maximal expression of the bhu genes occurs under iron starvation conditions only in the presence of heme iron sources.
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Affiliation(s)
- Carin K Vanderpool
- Department of Microbiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455-0312, USA
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Beare PA, For RJ, Martin LW, Lamont IL. Siderophore-mediated cell signalling in Pseudomonas aeruginosa: divergent pathways regulate virulence factor production and siderophore receptor synthesis. Mol Microbiol 2003; 47:195-207. [PMID: 12492864 DOI: 10.1046/j.1365-2958.2003.03288.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Under iron-limiting conditions, Pseudomonas aeruginosa produces a siderophore called pyoverdine. Pyoverdine is secreted into the extracellular environment where it chelates iron, and the resulting ferri-pyoverdine complexes are transported back into the bacteria by a cell surface receptor protein FpvA. Pyoverdine also acts as a signalling molecule inducing the production of three secreted virulence factors. Binding of ferri-pyoverdine to FpvA transduces a signal to the periplasmic part of the membrane-spanning antisigma factor FpvR. The signal is transmitted to the cytoplasmic part of FpvR, which controls the activity of an extracytoplasmic family (ECF) sigma factor protein PvdS. This results in the production of the virulence factors pyoverdine, exotoxin A and PrpL endoprotease. Here, we show that a second divergent branch of this signalling pathway regulates the production of the FpvA protein. FpvR negatively regulates the activity of a second ECF sigma factor, FpvI, which is required for the synthesis of FpvA, and the presence of ferri-pyoverdine greatly increases the activity of FpvI so that production of FpvA is induced. To the best of our knowledge, this is the first example of a branched signalling system of this sort and the first example of an antisigma factor protein (FpvR) that directly regulates the activities of two different ECF sigma factor proteins (PvdS and FpvI).
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Affiliation(s)
- Paul A Beare
- Department of Biochemistry, University of Otago, PO Box 56, Dunedin, New Zealand
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Visca P, Leoni L, Wilson MJ, Lamont IL. Iron transport and regulation, cell signalling and genomics: lessons from Escherichia coli and Pseudomonas. Mol Microbiol 2002; 45:1177-90. [PMID: 12207687 DOI: 10.1046/j.1365-2958.2002.03088.x] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A variety of bacterial species secrete and take up chelating compounds that enable acquisition of iron (siderophores). It has become clear that a common feature in regulation of different iron acquisition systems is the involvement of alternative sigma factor proteins of the extracytoplasmic function (ECF) family. Two of these proteins, PvdS from Pseudomonas aeruginosa and FecI from Escherichia coli K-12, have been studied extensively. PvdS directs transcription of genes required for the biosynthesis of a siderophore, pyoverdine, and FecI causes expression of genes for uptake of ferric citrate. FecI forms part of a signalling system that responds to the presence of ferric citrate. Here, we review recent advances in understanding of PvdS and of the Fec signalling system. PvdS and FecI are part of a distinct subfamily of ECF sigma factors involved in iron acquisition and hence named the iron-starvation sigmas. Analysis of microbial genome sequences shows that Fec-like signalling systems are present in a wide range of species and many such systems may be present in a single species. The availability of tools for large-scale genome analysis is likely to lead to rapid advances in our understanding of this expanding family of proteins.
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Affiliation(s)
- Paolo Visca
- Molecular Microbiology Unit, National Institute for Infectious Diseases, Via Portuense 292, 00149 Rome, Italy
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46
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Ekins A, Niven DF. Production of transferrin receptors by Histophilus ovis: three of five strains require two signals. Can J Microbiol 2001; 47:417-23. [PMID: 11400732 DOI: 10.1139/w01-022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Five strains of Histophilus ovis (9L, 642A, 714, 5688T, and 3384Y) were investigated with respect to iron acquisition. All strains used ovine, bovine, and goat transferrins (Tfs), but not porcine or human Tfs, as iron sources for growth. In solid phase binding assays, total membranes from only two (9L and 642A) of the five strains, grown under iron-restricted conditions, were able to bind Tfs (ovine, bovine, and goat, but not porcine or human). However, when the organisms were grown under iron-restricted conditions in the presence of bovine transferrin (Tf), total membranes from all strains exhibited Tf binding (as above); competition experiments demonstrated that all three Tfs (ovine, bovine, and goat) were bound by the same receptor(s). Membranes from organisms grown under iron-replete conditions in the presence or absence of bovine Tf failed to bind any of the test Tfs. An affinity-isolation procedure allowed the isolation of two putative Tf-binding polypeptides (78 and 66 kDa) from total membranes of strains 9L and 642A grown under iron-restricted conditions, and from membranes of all strains if the growth medium also contained Tf. It is concluded that all strains tested acquire Tf-bound iron by means of siderophore-independent mechanisms involving surface receptors analogous to the Tf-binding proteins (TbpA and TbpB) found in comparable organisms; although iron restriction alone is sufficient to promote the expression of these proteins by strains 9L and 642A, their production by strains 714, 5688T, and 3384Y appears to require two signals, iron restriction and the presence of Tf.
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Affiliation(s)
- A Ekins
- Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, QC, Canada
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Pradel E, Locht C. Expression of the putative siderophore receptor gene bfrZ is controlled by the extracytoplasmic-function sigma factor BupI in Bordetella bronchiseptica. J Bacteriol 2001; 183:2910-7. [PMID: 11292812 PMCID: PMC99509 DOI: 10.1128/jb.183.9.2910-2917.2001] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2000] [Accepted: 01/30/2001] [Indexed: 11/20/2022] Open
Abstract
A new gene from Bordetella bronchiseptica, bfrZ encoding a putative siderophore receptor, was identified in a Fur-repressor titration assay. A bfrZ null mutant was constructed by allelic exchange. The protein profile of this mutant is similar to that of the wild-type parent strain. The BfrZ(-)-BfrZ(+) isogenic pair was tested for utilization of 132 different siderophores as iron sources. None of these iron sources acted as a ligand for BfrZ. Translational bfrZ::phoA and transcriptional bfrZ::lacZ fusions were introduced into the B. bronchiseptica bfrZ locus. No alkaline phosphatase or beta-galactosidase activity was detected. Sequence analysis of the bfrZ upstream region revealed the presence of two tightly linked genes, bupI and bupR. Both of these genes are located downstream from a Fur-binding sequence. BupI is homologous to Escherichia coli FecI and Pseudomonas putida PupI and belongs to the family of extracytoplasmic-function sigma factors involved in transcription of genes with extracytoplasmic functions. BupR is homologous to the FecR and PupR antisigma factors and is predicted to be localized in the inner membrane. Similar to the surface signaling receptors FecA and PupB, BfrZ bears an N-terminal extension. We found that bfrZ is not transcribed when bupI and bupR are expressed at the same level. However, overexpression of bupI from a multicopy plasmid triggers bfrZ transcription, and under these conditions BfrZ was detected in membrane fractions. By analogy with the FecI-FecR-FecA and PupI-PupR-PupB systems, our data suggest that bfrZ expression is inducible by binding of the cognate ligand to BfrZ and transduction of a signal through the envelope.
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Affiliation(s)
- E Pradel
- INSERM U447, Institut Pasteur de Lille, 59019 Lille Cedex, France
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Brickman TJ, Kang HY, Armstrong SK. Transcriptional activation of Bordetella alcaligin siderophore genes requires the AlcR regulator with alcaligin as inducer. J Bacteriol 2001; 183:483-9. [PMID: 11133941 PMCID: PMC94903 DOI: 10.1128/jb.183.2.483-489.2001] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genetic and biochemical studies have established that Fur and iron mediate repression of Bordetella alcaligin siderophore system (alc) genes under iron-replete nutritional growth conditions. In this study, transcriptional analyses using Bordetella chromosomal alc-lacZ operon fusions determined that maximal alc gene transcriptional activity under iron starvation stress conditions is dependent on the presence of alcaligin siderophore. Mutational analysis and genetic complementation confirmed that alcaligin-responsive transcriptional activation of Bordetella alcaligin system genes is dependent on AlcR, a Fur-regulated AraC-like positive transcriptional regulator encoded within the alcaligin gene cluster. AlcR-mediated transcriptional activation is remarkably sensitive to inducer, occurring at extremely low alcaligin concentrations. This positive autogenous control circuit involving alcaligin siderophore as the inducer for AlcR-mediated transcriptional activation of alcaligin siderophore biosynthesis and transport genes coordinates environmental and intracellular signals for maximal expression of these genes under conditions in which the presence of alcaligin in the environment is perceived.
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Affiliation(s)
- T J Brickman
- Department of Microbiology and Immunology, East Carolina University School of Medicine, Greenville, North Carolina 27858-4354, USA
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Rodrigue A, Quentin Y, Lazdunski A, Méjean V, Foglino M. Two-component systems in Pseudomonas aeruginosa: why so many? Trends Microbiol 2000; 8:498-504. [PMID: 11121759 DOI: 10.1016/s0966-842x(00)01833-3] [Citation(s) in RCA: 179] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Screening the Pseudomonas aeruginosa genome has led to the identification of the highest number of putative genes encoding two-component regulatory systems of all bacterial genomes sequenced to date (64 and 63 encoding response regulators and histidine kinases, respectively). Sixteen atypical kinases, among them 11 devoid of an Hpt domain, and three independent Hpt modules were retrieved. These data suggest that P. aeruginosa possesses complex control strategies with which to respond to environmental challenges.
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Affiliation(s)
- A Rodrigue
- Laboratoire d'Ingiénérie des Systemes Macromoléculaires, Centre National de la Recherche Scientifique, Marseille, France
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Abstract
During the past decade significant progress has been made towards identifying some of the schemes that Pseudomonas aeruginosa uses to obtain iron and towards cataloguing and characterizing many of the genes and gene products that are likely to play a role in these processes. This review will largely recount what we have learned in the past few years about how P. aeruginosa regulates its acquisition, intake and, to some extent, trafficking of iron, and the role of iron acquisition systems in the virulence of this remarkable opportunistic pathogen. More specifically, the genetics, biochemistry and biology of an essential regulator (Ferric uptake regulator - Fur) and a Fur-regulated alternative sigma factor (PvdS), which are central to these processes, will be discussed. These regulatory proteins directly or indirectly regulate a substantial number of other genes encoding proteins with remarkably diverse functions. These genes include: (i) other regulatory genes, (ii) genes involved in basic metabolic processes (e.g. Krebs cycle), (iii) genes required to survive oxidative stress (e.g. superoxide dismutase), (iv) genes necessary for scavenging iron (e.g. siderophores and their cognate receptors) or genes that contribute to the virulence (e.g. exotoxin A) of this opportunistic pathogen. Despite this recent expansion of knowledge about the response of P. aeruginosa to iron, many significant biological issues surrounding iron acquisition still need to be addressed. Virtually nothing is known about which of the distinct iron acquisition mechanisms P. aeruginosa brings to bear on these questions outside the laboratory, whether it be in soil, in a pipeline, on plants or in the lungs of cystic fibrosis patients.
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Affiliation(s)
- M L Vasil
- Department of Microbiology, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
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