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Holland M, Farinella DN, Cruz-Lorenzo E, Laubscher MI, Doakes DA, Ramos MA, Kubota N, Levin TC. L. pneumophila resists its self-harming metabolite HGA via secreted factors and collective peroxide scavenging. mBio 2023; 14:e0120723. [PMID: 37728338 PMCID: PMC10653783 DOI: 10.1128/mbio.01207-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/25/2023] [Indexed: 09/21/2023] Open
Abstract
IMPORTANCE Before environmental opportunistic pathogens can infect humans, they must first successfully grow and compete with other microbes in nature, often via secreted antimicrobials. We previously discovered that the bacterium Legionella pneumophila, the causative agent of Legionnaires' disease, can compete with other microbes via a secreted molecule called HGA. Curiously, L. pneumophila strains that produce HGA is not wholly immune to its toxicity, making it a mystery how these bacteria can withstand the "friendly fire" of potentially self-targeting antimicrobials during inter-bacterial battles. Here, we identify several strategies that allow the high-density bacterial populations that secrete HGA to tolerate its effects. Our study clarifies how HGA works. It also points to some explanations of why it is difficult to disinfect L. pneumophila from the built environment and prevent disease outbreaks.
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Affiliation(s)
- Mische Holland
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Danielle N. Farinella
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Emily Cruz-Lorenzo
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Madelyn I. Laubscher
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Darian A. Doakes
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, California, USA
| | - Maria A. Ramos
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Nanami Kubota
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Tera C. Levin
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Lopez AE, Grigoryeva LS, Barajas A, Cianciotto NP. Legionella pneumophila Rhizoferrin Promotes Bacterial Biofilm Formation and Growth within Amoebae and Macrophages. Infect Immun 2023; 91:e0007223. [PMID: 37428036 PMCID: PMC10429650 DOI: 10.1128/iai.00072-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/20/2023] [Indexed: 07/11/2023] Open
Abstract
Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine lung. Yet, past studies failed to identify a role for the rhizoferrin biosynthetic gene (lbtA) in L. pneumophila infection of host cells, suggesting the siderophore's importance was solely linked to extracellular survival. To test the possibility that rhizoferrin's relevance to intracellular infection was missed due to functional redundancy with the ferrous iron transport (FeoB) pathway, we characterized a new mutant lacking both lbtA and feoB. This mutant was highly impaired for growth on bacteriological media that were only modestly depleted of iron, confirming that rhizoferrin-mediated ferric iron uptake and FeoB-mediated ferrous iron uptake are critical for iron acquisition. The lbtA feoB mutant, but not its lbtA-containing complement, was also highly defective for biofilm formation on plastic surfaces, demonstrating a new role for the L. pneumophila siderophore in extracellular survival. Finally, the lbtA feoB mutant, but not its complement containing lbtA, proved to be greatly impaired for growth in Acanthamoeba castellanii, Vermamoeba vermiformis, and human U937 cell macrophages, revealing that rhizoferrin does promote intracellular infection by L. pneumophila. Moreover, the application of purified rhizoferrin triggered cytokine production from the U937 cells. Rhizoferrin-associated genes were fully conserved across the many sequenced strains of L. pneumophila examined but were variably present among strains from the other species of Legionella. Outside of Legionella, the closest match to the L. pneumophila rhizoferrin genes was in Aquicella siphonis, another facultative intracellular parasite of amoebae.
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Affiliation(s)
- Alberto E. Lopez
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Lubov S. Grigoryeva
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Armando Barajas
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
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Lopez AE, Mayoral J, Cianciotto NP. Complete Genome Sequence of Legionella cardiaca Strain H63 T, Isolated from a Case of Native Valve Endocarditis. Microbiol Resour Announc 2023; 12:e0017523. [PMID: 37310280 PMCID: PMC10353460 DOI: 10.1128/mra.00175-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/30/2023] [Indexed: 06/14/2023] Open
Abstract
We report the complete genome sequence of Legionella cardiaca strain H63T, which had been isolated from aortic valve tissue from a patient with native endocarditis. The genome assembly contains a single 3,477,232-bp contig, with a G+C content of 38.59%, and is predicted to encode 2,948 proteins.
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Affiliation(s)
- Alberto E. Lopez
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Joshua Mayoral
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
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Styczynski M, Rogowska A, Nyabayo C, Decewicz P, Romaniuk F, Pączkowski C, Szakiel A, Suessmuth R, Dziewit L. Heterologous production and characterization of a pyomelanin of Antarctic Pseudomonas sp. ANT_H4: a metabolite protecting against UV and free radicals, interacting with iron from minerals and exhibiting priming properties toward plant hairy roots. Microb Cell Fact 2022; 21:261. [PMID: 36527127 PMCID: PMC9756463 DOI: 10.1186/s12934-022-01990-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/10/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Antarctica has one of the most extreme environments in the world. This region is inhabited by specifically adapted microorganisms that produce various unique secondary metabolites (e.g. pigments) enabling their survival under the harsh environmental conditions. It was already shown that these natural, biologically active molecules may find application in various fields of biotechnology. RESULTS In this study, a cold-active brown-pigment-producing Pseudomonas sp. ANT_H4 strain was characterized. In-depth genomic analysis combined with the application of a fosmid expression system revealed two different pathways of melanin-like compounds biosynthesis by the ANT_H4 strain. The chromatographic behavior and Fourier-transform infrared spectroscopic analyses allowed for the identification of the extracted melanin-like compound as a pyomelanin. Furthermore, optimization of the production and thorough functional analyses of the pyomelanin were performed to test its usability in biotechnology. It was confirmed that ANT_H4-derived pyomelanin increases the sun protection factor, enables scavenging of free radicals, and interacts with the iron from minerals. Moreover, it was shown for the first time that pyomelanin exhibits priming properties toward Calendula officinalis hairy roots in in vitro cultures. CONCLUSIONS Results of the study indicate the significant biotechnological potential of ANT_H4-derived pyomelanin and open opportunities for future applications. Taking into account protective features of analyzed pyomelanin it may be potentially used in medical biotechnology and cosmetology. Especially interesting was showing that pyomelanin exhibits priming properties toward hairy roots, which creates a perspective for its usage for the development of novel and sustainable agrotechnical solutions.
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Affiliation(s)
- Michal Styczynski
- grid.12847.380000 0004 1937 1290Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Agata Rogowska
- grid.12847.380000 0004 1937 1290Department of Plant Biochemistry, Institute of Biochemistry, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Christine Nyabayo
- grid.6734.60000 0001 2292 8254Institute of Chemistry, Technical University of Berlin, Berlin, Germany
| | - Przemyslaw Decewicz
- grid.12847.380000 0004 1937 1290Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Filip Romaniuk
- grid.12847.380000 0004 1937 1290Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Cezary Pączkowski
- grid.12847.380000 0004 1937 1290Department of Plant Biochemistry, Institute of Biochemistry, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Anna Szakiel
- grid.12847.380000 0004 1937 1290Department of Plant Biochemistry, Institute of Biochemistry, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Roderich Suessmuth
- grid.6734.60000 0001 2292 8254Institute of Chemistry, Technical University of Berlin, Berlin, Germany
| | - Lukasz Dziewit
- grid.12847.380000 0004 1937 1290Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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Lorquin F, Piccerelle P, Orneto C, Robin M, Lorquin J. New insights and advances on pyomelanin production: from microbial synthesis to applications. J Ind Microbiol Biotechnol 2022; 49:6575554. [PMID: 35482661 PMCID: PMC9338888 DOI: 10.1093/jimb/kuac013] [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: 01/24/2022] [Accepted: 04/21/2022] [Indexed: 11/14/2022]
Abstract
Pyomelanin is a brown-black phenolic polymer and results from the oxidation of homogentisic acid (HGA) in the L-tyrosine pathway. As part of the research for natural and active ingredients issued from realistic bioprocesses, this work re-evaluates the HGA pigment and makes an updated inventory of its syntheses, microbial pathways, and properties, with tracks and recent advances for its large-scale production. The mechanism of the HGA polymerization is also well documented. In alkaptonuria, pyomelanin formation leads to connective tissue damages and arthritis, most probably due to the ROS issued from HGA oxidation. While UV radiation on human melanin may generate degradation products, pyomelanin is not photodegradable, is hyperthermostable, and has other properties better than the L-Dopa melanin. This review aims to raise awareness about the potential of this pigment for various applications, not only for skin coloring and protection but also for other cells, materials, and as a promising (semi)conductor for bioelectronics and energy.
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Affiliation(s)
- Faustine Lorquin
- Aix-Marseille Université, Mediterranean Institute of Oceanology (MIO), 163 avenue de Luminy, 13288 Marseille Cedex 9, France.,Aix-Marseille Université, Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), 27 boulevard Jean Moulin, 13385 Marseille Cedex 5, France
| | - Philippe Piccerelle
- Aix-Marseille Université, Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), 27 boulevard Jean Moulin, 13385 Marseille Cedex 5, France
| | - Caroline Orneto
- Aix-Marseille Université, Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), 27 boulevard Jean Moulin, 13385 Marseille Cedex 5, France
| | - Maxime Robin
- Aix-Marseille Université, Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), 27 boulevard Jean Moulin, 13385 Marseille Cedex 5, France
| | - Jean Lorquin
- Aix-Marseille Université, Mediterranean Institute of Oceanology (MIO), 163 avenue de Luminy, 13288 Marseille Cedex 9, France
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Pyomelanin produced by Streptomyces sp. ZL-24 and its protective effects against SH-SY5Y cells injury induced by hydrogen peroxide. Sci Rep 2021; 11:16649. [PMID: 34404820 PMCID: PMC8371117 DOI: 10.1038/s41598-021-94598-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 07/12/2021] [Indexed: 02/07/2023] Open
Abstract
A soluble melanin pigment produced by Streptomyces sp. ZL-24 was purified and named StrSM. The elemental analysis of StrSM showed it consists of carbon, hydrogen, and oxygen. The spectrum analysis, including ultraviolet-visible absorption spectrum, Fourier-transform infrared spectrum, and pyrolysis-gas chromatography-mass spectrometry, indicated that StrSM might be pyomelanin. High performance liquid chromatography and liquid chromatography-mass spectra analysis of intermediate metabolite showed the presence of homogentisic acid (HGA). Moreover, the enzyme 4-hydroxyphenylpyruvate dioxygenase, involved in HGA biosynthesis, showed high activity during melanin production. Subsequently, a tyrosinase gene (melC2) and hydroxyphenylpyruvate dioxygenase gene double mutant demonstrated StrSM is pyomelanin. In vitro bioactivity assay showed that StrSM had excellent protective capability against SH-SY5Y cell oxidative injury. To our knowledge, the results firstly provide comprehensive data on Streptomyces pyomelanin identification and a promising candidate compound to treat oxidative injury of neurocytes.
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Lorquin F, Ziarelli F, Amouric A, Di Giorgio C, Robin M, Piccerelle P, Lorquin J. Production and properties of non-cytotoxic pyomelanin by laccase and comparison to bacterial and synthetic pigments. Sci Rep 2021; 11:8538. [PMID: 33879803 PMCID: PMC8058095 DOI: 10.1038/s41598-021-87328-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 03/15/2021] [Indexed: 11/09/2022] Open
Abstract
Pyomelanin is a polymer of homogentisic acid synthesized by microorganisms. This work aimed to develop a production process and evaluate the quality of the pigment. Three procedures have been elaborated and optimized, (1) an HGA-Mn2+ chemical autoxidation (PyoCHEM yield 0.317 g/g substrate), (2) an induced bacterial culture of Halomonas titanicae through the 4-hydroxyphenylacetic acid-1-hydroxylase route (PyoBACT, 0.55 g/L), and (3) a process using a recombinant laccase extract with the highest level produced (PyoENZ, 1.25 g/g substrate) and all the criteria for a large-scale prototype. The chemical structures had been investigated by 13C solid-state NMR (CP-MAS) and FTIR. Car-Car bindings predominated in the three polymers, Car-O-Car (ether) linkages being absent, proposing mainly C3-C6 (α-bindings) and C4-C6 (β-bindings) configurations. This work highlighted a biological decarboxylation by the laccase or bacterial oxidase(s), leading to the partly formation of gentisyl alcohol and gentisaldehyde that are integral parts of the polymer. By comparison, PyoENZ exhibited an Mw of 5,400 Da, was hyperthermostable, non-cytotoxic even after irradiation, scavenged ROS induced by keratinocytes, and had a highly DPPH-antioxidant and Fe3+-reducing activity. As a representative pigment of living cells and an available standard, PyoENZ might also be useful for applications in extreme conditions and skin protection.
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Affiliation(s)
- Faustine Lorquin
- Mediterranean Institute of Oceanology (MIO), Aix-Marseille Université, 163 avenue de Luminy, 13288, Marseille Cedex 9, France.,Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), Aix-Marseille Université, 27 Boulevard Jean Moulin, 13385, Marseille Cedex 5, France
| | - Fabio Ziarelli
- Fédération Sciences Chimiques de Marseille, Aix-Marseille Université, 52 Avenue Escadrille Normandie Niemen, 13397, Marseille, France
| | - Agnès Amouric
- Mediterranean Institute of Oceanology (MIO), Aix-Marseille Université, 163 avenue de Luminy, 13288, Marseille Cedex 9, France
| | - Carole Di Giorgio
- Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), Aix-Marseille Université, 27 Boulevard Jean Moulin, 13385, Marseille Cedex 5, France
| | - Maxime Robin
- Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), Aix-Marseille Université, 27 Boulevard Jean Moulin, 13385, Marseille Cedex 5, France
| | - Philippe Piccerelle
- Mediterranean Institute of Marine and Terrestrial Biodiversity and Ecology (IMBE), Aix-Marseille Université, 27 Boulevard Jean Moulin, 13385, Marseille Cedex 5, France
| | - Jean Lorquin
- Mediterranean Institute of Oceanology (MIO), Aix-Marseille Université, 163 avenue de Luminy, 13288, Marseille Cedex 9, France.
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Tran T, Dawrs SN, Norton GJ, Virdi R, Honda JR. Brought to you courtesy of the red, white, and blue-pigments of nontuberculous mycobacteria. AIMS Microbiol 2020; 6:434-450. [PMID: 33364537 PMCID: PMC7755587 DOI: 10.3934/microbiol.2020026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 11/10/2020] [Indexed: 11/18/2022] Open
Abstract
Pigments are chromophores naturally synthesized by animals, plants, and microorganisms, as well as produced synthetically for a wide variety of industries such as food, pharmaceuticals, and textiles. Bacteria produce various pigments including melanin, pyocyanin, bacteriochlorophyll, violacein, prodigiosin, and carotenoids that exert diverse biological activities as antioxidants and demonstrate anti-inflammatory, anti-cancer, and antimicrobial properties. Nontuberculous mycobacteria (NTM) include over 200 environmental and acid-fast species; some of which can cause opportunistic disease in humans. Early in the study of mycobacteriology, the vast majority of mycobacteria were not known to synthesize pigments, particularly NTM isolates of clinical significance such as the Mycobacterium avium complex (MAC) species. This paper reviews the overall understanding of microbial pigments, their applications, as well as highlights what is currently known about pigments produced by NTM, the circumstances that trigger their production, and their potential roles in NTM survival and virulence.
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Affiliation(s)
- Tru Tran
- College of Osteopathic Medicine, Lake Erie College of Osteopathic Medicine, Bradenton, Florida, USA
| | - Stephanie N Dawrs
- Center for Genes, Environment, and Health; Department of Immunology and Genomic Research, National Jewish Health, Denver, Colorado, USA
| | - Grant J Norton
- Center for Genes, Environment, and Health; Department of Immunology and Genomic Research, National Jewish Health, Denver, Colorado, USA
| | - Ravleen Virdi
- Center for Genes, Environment, and Health; Department of Immunology and Genomic Research, National Jewish Health, Denver, Colorado, USA
| | - Jennifer R Honda
- Center for Genes, Environment, and Health; Department of Immunology and Genomic Research, National Jewish Health, Denver, Colorado, USA
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9
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Mitra M, Nguyen KMAK, Box TW, Gilpin JS, Hamby SR, Berry TL, Duckett EH. Isolation and characterization of a novel bacterial strain from a Tris-Acetate-Phosphate agar medium plate of the green micro-alga Chlamydomonas reinhardtii that can utilize common environmental pollutants as a carbon source. F1000Res 2020; 9:656. [PMID: 32855811 PMCID: PMC7425125 DOI: 10.12688/f1000research.24680.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/19/2020] [Indexed: 12/28/2022] Open
Abstract
Background:Chlamydomonas reinhardtii, a green micro-alga can be grown at the lab heterotrophically or photo-heterotrophically in Tris-Phosphate-Acetate (TAP) medium which contains acetate as the sole carbon source. When grown in TAP medium,
Chlamydomonas can utilize the exogenous acetate in the medium for gluconeogenesis using the glyoxylate cycle, which is also present in many bacteria and higher plants. A novel bacterial strain, LMJ, was isolated from a contaminated TAP medium plate of
Chlamydomonas. We present our work on the isolation and physiological and biochemical characterizations of LMJ. Methods: Several microbiological tests were conducted to characterize LMJ, including its sensitivity to four antibiotics. We amplified and sequenced partially the 16S rRNA gene of LMJ. We tested if LMJ can utilize cyclic alkanes, aromatic hydrocarbons, poly-hydroxyalkanoates, and fresh and combusted car motor oil as the sole carbon source on Tris-Phosphate (TP) agar medium plates for growth. Results: LMJ is a gram-negative rod, oxidase-positive, mesophilic, non-enteric, pigmented, salt-sensitive bacterium. LMJ can ferment glucose, is starch hydrolysis-negative, and is very sensitive to penicillin and chloramphenicol. Preliminary spectrophotometric analyses indicate LMJ produces pyomelanin. NCBI-BLAST analyses of the partial 16S rRNA gene sequence of LMJ showed that it matched to that of an uncultured bacterium clone LIB091_C05_1243. The nearest genus relative of LMJ is an
Acidovorax sp. strain. LMJ was able to use alkane hydrocarbons, fresh and combusted car motor oil, poly-hydroxybutyrate, phenanthrene, naphthalene, benzoic acid and phenyl acetate as the sole carbon source for growth on TP-agar medium plates. Conclusions: LMJ has 99.14% sequence identity with the
Acidovorax sp. strain A16OP12 whose genome has not been sequenced yet. LMJ’s ability to use chemicals that are common environmental pollutants makes it a promising candidate for further investigation for its use in bioremediation and, provides us with an incentive to sequence its genome.
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Affiliation(s)
- Mautusi Mitra
- Department of Biology, University of West Georgia, Carrollton, Georgia, 30118, USA
| | - Kevin Manoap-Anh-Khoa Nguyen
- Department of Biology, University of West Georgia, Carrollton, Georgia, 30118, USA.,Department of Mechanical Engineering, Kennesaw State University, Marietta, Georgia, 30060, USA
| | - Taylor Wayland Box
- Department of Biology, University of West Georgia, Carrollton, Georgia, 30118, USA
| | - Jesse Scott Gilpin
- Department of Biology, University of West Georgia, Carrollton, Georgia, 30118, USA
| | - Seth Ryan Hamby
- Department of Biology, University of West Georgia, Carrollton, Georgia, 30118, USA
| | - Taylor Lynne Berry
- Carrollton High School, Carrollton, Georgia, 30117, USA.,Department of Chemistry and Biochemistry, University of North Georgia, Dahlonega, Georgia, 30597, USA
| | - Erin Harper Duckett
- Department of Biology, University of West Georgia, Carrollton, Georgia, 30118, USA
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Isolation of Efficient Metal-Binding Bacteria from Boreal Peat Soils and Development of Microbial Biosorbents for Improved Nickel Scavenging. WATER 2020. [DOI: 10.3390/w12072000] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Boreal peatlands with low iron availability are a potential, but rarely studied, source for the isolation of bacteria for applications in metal sorption. The present research focused on the isolation and identification of Actinobacteria from northern Finland, which can produce siderophores for metal capture. The 16S rDNA analysis showed that isolated strains belonged to Firmicutes (Bacillus sp.) and Actinobacteria (Microbacterium sp.). The culture most efficiently producing siderophores in the widest array of the media was identified as Microbacterium sp. The most appropriate media for siderophore production by the Microbacterium strain were those prepared with glucose supplemented with asparagine or glutamic acid, and those prepared with glycerol or fructose supplemented with glutamic acid. The microorganism obtained and its siderophores were used to develop Sphagnum moss-based hybrid biosorbents. It was showed that the hybrid sorbent could bind nickel ions and that the nickel removal was enhanced by the presence of siderophores. Bacterial cells did not have a significant effect on sorption efficiency compared to the use of siderophores alone. The microbial biosorbent could be applied in the final effluent treatment stage for wastewater with low metal concentrations.
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11
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Pavan ME, López NI, Pettinari MJ. Melanin biosynthesis in bacteria, regulation and production perspectives. Appl Microbiol Biotechnol 2019; 104:1357-1370. [PMID: 31811318 DOI: 10.1007/s00253-019-10245-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/25/2019] [Accepted: 11/04/2019] [Indexed: 12/26/2022]
Abstract
The production of black pigments in bacteria was discovered more than a century ago and related to tyrosine metabolism. However, their diverse biological roles and the control of melanin synthesis in different bacteria have only recently been investigated. The broad distribution of these pigments suggests that they have an important role in a variety of organisms. Melanins protect microorganisms from many environmental stress conditions, ranging from ultraviolet radiation and toxic heavy metals to oxidative stress. Melanins can also affect bacterial interactions with other organisms and are important in pathogenesis and survival in many environments. Bacteria produce several types of melanin through dedicated pathways or as a result of enzymatic imbalances in altered metabolic routes. The control of the melanin synthesis in bacteria involves metabolic and transcriptional regulation, but many aspects remain still largely unknown. The diverse properties of melanins have spurred a large number of applications, and recent efforts have been done to produce the pigment at biotechnologically relevant scales.
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Affiliation(s)
- María Elisa Pavan
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Nancy I López
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina. .,IQUIBICEN-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
| | - M Julia Pettinari
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina. .,IQUIBICEN-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
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12
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The iron-regulated vacuolar Legionella pneumophila MavN protein is a transition-metal transporter. Proc Natl Acad Sci U S A 2019; 116:17775-17785. [PMID: 31431530 DOI: 10.1073/pnas.1902806116] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Legionella pneumophila causes a potentially fatal form of pneumonia by replicating within macrophages in the Legionella-containing vacuole (LCV). Bacterial survival and proliferation within the LCV rely on hundreds of secreted effector proteins comprising high functional redundancy. The vacuolar membrane-localized MavN, hypothesized to support iron transport, is unique among effectors because loss-of-function mutations result in severe intracellular growth defects. We show here an iron starvation response by L. pneumophila after infection of macrophages that was prematurely induced in the absence of MavN, consistent with MavN granting access to limiting cellular iron stores. MavN cysteine accessibilities to a membrane-impermeant label were determined during macrophage infections, revealing a topological pattern supporting multipass membrane transporter models. Mutations to several highly conserved residues that can take part in metal recognition and transport resulted in defective intracellular growth. Purified MavN and mutant derivatives were directly tested for transporter activity after heterologous purification and liposome reconstitution. Proteoliposomes harboring MavN exhibited robust transport of Fe2+, with the severity of defect of most mutants closely mimicking the magnitude of defects during intracellular growth. Surprisingly, MavN was equivalently proficient at transporting Fe2+, Mn2+, Co2+, or Zn2+ Consequently, flooding infected cells with either Mn2+ or Zn2+ allowed collaboration with iron to enhance intracellular growth of L. pneumophila ΔmavN strains, indicating a clear role for MavN in transporting each of these ions. These findings reveal that MavN is a transition-metal-ion transporter that plays a critical role in response to iron limitation during Legionella infection.
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Bolognese F, Scanferla C, Caruso E, Orlandi VT. Bacterial melanin production by heterologous expression of 4‑hydroxyphenylpyruvate dioxygenase from Pseudomonas aeruginosa. Int J Biol Macromol 2019; 133:1072-1080. [DOI: 10.1016/j.ijbiomac.2019.04.061] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 03/27/2019] [Accepted: 04/10/2019] [Indexed: 02/06/2023]
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14
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Abstract
Communities of bacteria that cause Legionnaires' disease repel other bacteria by secreting an acid called HGA
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Affiliation(s)
- Elisa D Hughes
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, United States
| | - Michele S Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, United States
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15
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White RC, Cianciotto NP. Assessing the impact, genomics and evolution of type II secretion across a large, medically important genus: the Legionella type II secretion paradigm. Microb Genom 2019; 5. [PMID: 31166887 PMCID: PMC6617341 DOI: 10.1099/mgen.0.000273] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The type II secretion system (T2SS) plays a major role in promoting bacterial survival in the environment and in human hosts. One of the best characterized T2SS is that of Legionella pneumophila, the agent of Legionnaires’ disease. Secreting at least 25 proteins, including degradative enzymes, eukaryotic-like proteins and novel effectors, this T2SS contributes to the ability of L. pneumophila to grow at low temperatures, infect amoebal and macrophage hosts, damage lung tissue, evade the immune system, and undergo sliding motility. The genes encoding the T2SS are conserved across the genus Legionella, which includes 62 species and >30 pathogens in addition to L. pneumophila. The vast majority of effectors associated with L. pneumophila are shared by a large number of Legionella species, hinting at a critical role for them in the ecology of Legionella as a whole. However, no other species has the same repertoire as L. pneumophila, with, as a general rule, phylogenetically more closely related species sharing similar sets of effectors. T2SS effectors that are involved in infection of a eukaryotic host(s) are more prevalent throughout Legionella, indicating that they are under stronger selective pressure. The Legionella T2SS apparatus is closest to that of Aquicella (another parasite of amoebae), and a significant number of L. pneumophila effectors have their closest homologues in Aquicella. Thus, the T2SS of L. pneumophila probably originated within the order Legionellales, with some of its effectors having arisen within that Aquicella-like progenitor, while other effectors derived from the amoebal host, mimiviruses, fungi and less closely related bacteria.
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Affiliation(s)
- Richard C White
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
| | - Nicholas P Cianciotto
- 1 Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, IL 60611, USA
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16
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Levin TC, Goldspiel BP, Malik HS. Density-dependent resistance protects Legionella pneumophila from its own antimicrobial metabolite, HGA. eLife 2019; 8:46086. [PMID: 31134893 PMCID: PMC6598767 DOI: 10.7554/elife.46086] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/16/2019] [Indexed: 01/01/2023] Open
Abstract
To persist in microbial communities, the bacterial pathogen Legionella pneumophila must withstand competition from neighboring bacteria. Here, we find that L. pneumophila can antagonize the growth of other Legionella species using a secreted inhibitor: HGA (homogentisic acid). Unexpectedly, L. pneumophila can itself be inhibited by HGA secreted from neighboring, isogenic strains. Our genetic approaches further identify lpg1681 as a gene that modulates L. pneumophila susceptibility to HGA. We find that L. pneumophila sensitivity to HGA is density-dependent and cell intrinsic. Resistance is not mediated by the stringent response nor the previously described Legionella quorum-sensing pathway. Instead, L. pneumophila cells secrete HGA only when they are conditionally HGA-resistant, which allows these bacteria to produce a potentially self-toxic molecule while restricting the opportunity for self-harm. We propose that established Legionella communities may deploy molecules such as HGA as an unusual public good that can protect against invasion by low-density competitors. In the environment, bacteria frequently compete with each other for resources and space. These battles often involve the bacteria releasing toxins, antibiotics or other molecules that make it more difficult for their neighbors to grow. The bacteria also carry specific resistance genes that protect them from the effects of the molecules that they produce. Legionella pneumophila is a species of bacteria that infects people and causes a severe form of pneumonia known as Legionnaires’ disease. The bacteria spread in droplets of water from contaminated water systems such as sink faucets, cooling towers, water tanks, and other plumbing systems. In these water systems, L. pneumophila cells live within communities known as biofilms, which contain many different species of bacteria. These communities often include other species of Legionella that compete with L. pneumophila for similar nutrients. However, L. pneumophila was not known to produce any toxins or antibiotics, so it was not clear how it is able to survive in biofilms. Levin et al. used genetic approaches to investigate how L. pneumophila competes with other species of Legionella. The experiments found that this bacterium released a molecule called homogentisic acid (HGA) that reduced the growth of neighboring Legionella bacteria. Unexpectedly, L. pneumophila was not always resistant to HGA, despite secreting large quantities of this molecule. Instead, L. pneumophila cells were only resistant to HGA when the bacteria were living in crowded conditions. Previous studies have shown that HGA is widely produced by bacteria and other organisms – including humans – but this is the first time it has been shown that this molecule limits the ability of bacteria to grow. The work of Levin et al. suggests that HGA may help L. pneumophila bacteria to persist in biofilms, but more work needs to be done to test this idea. A possible next step is to test whether drugs that inhibit the production of HGA can eliminate Legionella bacteria from water systems. If so, similar treatments could potentially be used to stop and prevent outbreaks of Legionnaires’ disease in the future.
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Affiliation(s)
- Tera C Levin
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Brian P Goldspiel
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Harmit S Malik
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.,Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, United States
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17
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Analysis of Iron Requirements and Siderophore Production. Methods Mol Biol 2019. [PMID: 30694482 DOI: 10.1007/978-1-4939-9048-1_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
This chapter describes the methods for inducing, detecting, and purifying the Legionella pneumophila siderophore. The first protocol details the methods by which L. pneumophila is cultured to facilitate production of the siderophore, rhizoferrin. This chapter then describes how to purify siderophore from culture supernatants through sequential reversed-phase/weak-anion exchange chromatography and high-performance liquid chromatography. The next section describes assays which allow the detection of the iron-binding capability and the biological activity of the purified siderophore. Lastly, this chapter describes the growth of L. pneumophila in chemically defined liquid medium (CDM) containing various iron sources as a method to assess the iron requirements of L. pneumophila.
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18
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Mekala LP, Mohammed M, Chinthalapati S, Chinthalapati VR. Pyomelanin production: Insights into the incomplete aerobic l-phenylalanine catabolism of a photosynthetic bacterium, Rubrivivax benzoatilyticus JA2. Int J Biol Macromol 2018; 126:755-764. [PMID: 30572055 DOI: 10.1016/j.ijbiomac.2018.12.142] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 12/13/2018] [Accepted: 12/16/2018] [Indexed: 02/06/2023]
Abstract
Rubrivivax benzoatilyticus JA2 is a metabolically versatile bacterium, thrives on a wide array of organic compounds under different growth modes. Though genomic insights revealed the aromatic compound catabolic potential of strain JA2 under anaerobic/aerobic conditions, the studies are largely restricted to anaerobic metabolism. The previous study on phenylalanine metabolism in strain JA2 indicated melanin-like pigment production under aerobic conditions; however, characterization of pigment and its biosynthetic pathway is not explored. The current study aims at the characterization of pigment and elucidation of its biosynthetic pathway. Strain JA2 utilized l-phenylalanine as source of nitrogen under anaerobic/aerobic conditions but not as a carbon source. Strain JA2 produced a brown-pigment under phenylalanine-amended aerobic conditions. Spectroscopic and physicochemical analysis identified the purified brown-pigment as a melanin. Further, the genomic insights revealed the presence of a complete set of genes related to pyomelanin synthesis. Identification of key metabolites l-tyrosine, 4-hydroxyphenylpyruvic acid and homogentisic acid and their respective enzyme activities further supports the pyomelanin synthesis. Moreover, the precursors feeding, pathway specific inhibitor studies confirmed the pyomelanin synthesis in strain JA2. Our study revealed an incomplete catabolism of phenylalanine; absence of ring cleavage gene, homogentisate dioxygenase leading to homogentisate accumulation thereby pyomelanin synthesis in strain JA2.
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Affiliation(s)
- Lakshmi Prasuna Mekala
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Mujahid Mohammed
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India
| | - Sasikala Chinthalapati
- Bacterial Discovery Laboratory, Centre for Environment, IST, JNT University Hyderabad, Kukatpally, Hyderabad 500 085, India
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19
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Bacterial Enzymes Catalyzing the Synthesis of 1,8-Dihydroxynaphthalene, a Key Precursor of Dihydroxynaphthalene Melanin, from Sorangium cellulosum. Appl Environ Microbiol 2018; 84:AEM.00258-18. [PMID: 29500263 DOI: 10.1128/aem.00258-18] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 02/21/2018] [Indexed: 12/27/2022] Open
Abstract
1,8-Dihydroxynaphthalene (1,8-DHN) is a key intermediate in the biosynthesis of DHN melanin, which is specific to fungi. In this study, we characterized the enzymatic properties of the gene products of an operon consisting of soceCHS1, bdsA, and bdsB from the Gram-negative bacterium Sorangium cellulosum Heterologous expression of soceCHS1, bdsA, and bdsB in Streptomyces coelicolor caused secretion of a dark-brown pigment into the broth. High-performance liquid chromatography (HPLC) analysis of the broth revealed that the recombinant strain produced 1,8-DHN, indicating that the operon encoded a novel enzymatic system for the synthesis of 1,8-DHN. Simultaneous incubation of the recombinant SoceCHS1, BdsA, and BdsB with malonyl-coenzyme A (malonyl-CoA) and NADPH resulted in the synthesis of 1,8-DHN. SoceCHS1, a type III polyketide synthase (PKS), catalyzed the synthesis of 1,3,6,8-tetrahydroxynaphthalene (T4HN) in vitro T4HN was in turn converted to 1,8-DHN by successive steps of reduction and dehydration, which were catalyzed by BdsA and BdsB. BdsA, which is a member of the aldo-keto reductase (AKR) superfamily, catalyzed the reduction of T4HN and 1,3,8-tetrahydroxynaphthalene (T3HN) to scytalone and vermelone, respectively. The stereoselectivity of T4HN reduction by BdsA occurred on the si-face to give (R)-scytalone with more than 99% optical purity. BdsB, a SnoaL2-like protein, catalyzed the dehydration of scytalone and vermelone to T3HN and 1,8-DHN, respectively. The fungal pathway for the synthesis of 1,8-DHN is composed of a type I PKS, naphthol reductases of the short-chain dehydrogenase/reductase (SDR) superfamily, and scytalone dehydratase (SD). These findings demonstrated 1,8-DHN synthesis by novel enzymes of bacterial origin.IMPORTANCE Although the DHN biosynthetic pathway was thought to be specific to fungi, we discovered novel DHN synthesis enzymes of bacterial origin. The biosynthesis of bacterial DHN utilized a type III PKS for polyketide synthesis, an AKR superfamily for reduction, and a SnoaL2-like NTF2 superfamily for dehydration, whereas the biosynthesis of fungal DHN utilized a type I PKS, SDR superfamily enzyme, and SD-like NTF2 superfamily. Surprisingly, the enzyme systems comprising the pathway were significantly different from each other, suggesting independent, parallel evolution leading to the same biosynthesis. DHN melanin plays roles in host invasion and adaptation to stress in pathogenic fungi and is therefore important to study. However, it is unclear whether DHN biosynthesis occurs in bacteria. Importantly, we did find that bacterial DHN biosynthetic enzymes were conserved among pathogenic bacteria.
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20
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Zeng Z, Cai X, Wang P, Guo Y, Liu X, Li B, Wang X. Biofilm Formation and Heat Stress Induce Pyomelanin Production in Deep-Sea Pseudoalteromonas sp. SM9913. Front Microbiol 2017; 8:1822. [PMID: 28983293 PMCID: PMC5613676 DOI: 10.3389/fmicb.2017.01822] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 09/06/2017] [Indexed: 01/24/2023] Open
Abstract
Pseudoalteromonas is an important bacterial genus present in various marine habitats. Many strains of this genus are found to be surface colonizers on marine eukaryotes and produce a wide range of pigments. However, the exact physiological role and mechanism of pigmentation were less studied. Pseudoalteromonas sp. SM9913 (SM9913), an non-pigmented strain isolated from the deep-sea sediment, formed attached biofilm at the solid–liquid interface and pellicles at the liquid–air interface at a wide range of temperatures. Lower temperatures and lower nutrient levels promoted the formation of attached biofilm, while higher nutrient levels promoted pellicle formation of SM9913. Notably, after prolonged incubation at higher temperatures growing planktonically or at the later stage of the biofilm formation, we found that SM9913 released a brownish pigment. By comparing the protein profile at different temperatures followed by qRT-PCR, we found that the production of pigment at higher temperatures was due to the induction of melA gene which is responsible for the synthesis of homogentisic acid (HGA). The auto-oxidation of HGA can lead to the formation of pyomelanin, which has been shown in other bacteria. Fourier Transform Infrared Spectrometer analysis confirmed that the pigment produced in SM9913 was pyomelanin-like compound. Furthermore, we demonstrated that, during heat stress and during biofilm formation, the induction level of melA gene was significantly higher than that of the hmgA gene which is responsible for the degradation of HGA in the L-tyrosine catabolism pathway. Collectively, our results suggest that the production of pyomelanin of SM9913 at elevated temperatures or during biofilm formation might be one of the adaptive responses of marine bacteria to environmental cues.
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Affiliation(s)
- Zhenshun Zeng
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China
| | - Xingsheng Cai
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China
| | - Yunxue Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China
| | - Xiaoxiao Liu
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China
| | - Baiyuan Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China.,Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of MicrobiologyGuangzhou, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, The South China Sea Institute of Oceanology, Chinese Academy of SciencesGuangzhou, China
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21
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Zeng Z, Guo XP, Cai X, Wang P, Li B, Yang JL, Wang X. Pyomelanin from Pseudoalteromonas lipolytica reduces biofouling. Microb Biotechnol 2017; 10:1718-1731. [PMID: 28834245 PMCID: PMC5658579 DOI: 10.1111/1751-7915.12773] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/14/2017] [Accepted: 06/15/2017] [Indexed: 01/11/2023] Open
Abstract
Members of the marine bacterial genus Pseudoalteromonas are efficient producers of antifouling agents that exert inhibitory effects on the settlement of invertebrate larvae. The production of pigmented secondary metabolites by Pseudoalteromonas has been suggested to play a role in surface colonization. However, the physiological characteristics of the pigments produced by Pseudoalteromonas remain largely unknown. In this study, we identified and characterized a genetic variant that hyperproduces a dark‐brown pigment and was generated during Pseudoalteromonas lipolytica biofilm formation. Through whole‐genome resequencing combined with targeted gene deletion and complementation, we found that a point mutation within the hmgA gene, which encodes homogentisate 1,2‐dioxygenase, is solely responsible for the overproduction of the dark‐brown pigment pyomelanin. In P. lipolytica, inactivation of the hmgA gene led to the formation of extracellular pyomelanin and greatly reduced larval settlement and metamorphosis of the mussel Mytilus coruscus. Additionally, the extracted pyomelanin from the hmgA deletion mutant and the in vitro‐synthesized pyomelanin also reduced larval settlement and metamorphosis of M. coruscus, suggesting that extracellular pyomelanin released from marine Pseudoalteromonas biofilm can inhibit the settlement of fouling organisms.
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Affiliation(s)
- Zhenshun Zeng
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Xing-Pan Guo
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, International Research Center for Marine Biosciences, Shanghai Ocean University, Shanghai, China
| | - Xingsheng Cai
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Pengxia Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Baiyuan Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
| | - Jin-Long Yang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, International Research Center for Marine Biosciences, Shanghai Ocean University, Shanghai, China
| | - Xiaoxue Wang
- Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
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22
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Abstract
Iron is an essential micronutrient for both microbes and humans alike. For well over half a century we have known that this element, in particular, plays a pivotal role in health and disease and, most especially, in shaping host-pathogen interactions. Intracellular iron concentrations serve as a critical signal in regulating the expression not only of high-affinity iron acquisition systems in bacteria, but also of toxins and other noted virulence factors produced by some major human pathogens. While we now are aware of many strategies that the host has devised to sequester iron from invading microbes, there are as many if not more sophisticated mechanisms by which successful pathogens overcome nutritional immunity imposed by the host. This review discusses some of the essential components of iron sequestration and scavenging mechanisms of the host, as well as representative Gram-negative and Gram-positive pathogens, and highlights recent advances in the field. Last, we address how the iron acquisition strategies of pathogenic bacteria may be exploited for the development of novel prophylactics or antimicrobials.
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23
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Characterization of 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione resistance in pyomelanogenic Pseudomonas aeruginosa DKN343. PLoS One 2017; 12:e0178084. [PMID: 28570601 PMCID: PMC5453437 DOI: 10.1371/journal.pone.0178084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 05/07/2017] [Indexed: 01/11/2023] Open
Abstract
Pyomelanin is a reddish-brown pigment that provides bacteria and fungi protection from oxidative stress, and is reported to contribute to infection persistence. Production of this pigment can be inhibited by the anti-virulence agent 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC). The Pseudomonas aeruginosa clinical isolate DKN343 exhibited high levels of resistance to NTBC, and the mechanism of pyomelanin production in this strain was uncharacterized. We determined that pyomelanin production in the clinical Pseudomonas aeruginosa isolate DKN343 was due to a loss of function in homogentisate 1,2-dioxygenase (HmgA). Several potential resistance mechanisms were investigated, and the MexAB-OprM efflux pump is required for resistance to NTBC. DKN343 has a frameshift mutation in NalC, which is a known indirect repressor of the mexAB-oprM operon. This frameshift mutation may contribute to the increased resistance of DKN343 to NTBC. Additional studies investigating the prevalence of resistance in pyomelanogenic microbes are necessary to determine the future applications of NTBC as an anti-virulence therapy.
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24
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Poyntner C, Blasi B, Arcalis E, Mirastschijski U, Sterflinger K, Tafer H. The Transcriptome of Exophiala dermatitidis during Ex-vivo Skin Model Infection. Front Cell Infect Microbiol 2016; 6:136. [PMID: 27822460 PMCID: PMC5075926 DOI: 10.3389/fcimb.2016.00136] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/06/2016] [Indexed: 12/12/2022] Open
Abstract
The black yeast Exophiala dermatitidis is a widespread polyextremophile and human pathogen, that is found in extreme natural habitats and man-made environments such as dishwashers. It can cause various diseases ranging from phaeohyphomycosis and systemic infections, with fatality rates reaching 40%. While the number of cases in immunocompromised patients are increasing, knowledge of the infections, virulence factors and host response is still scarce. In this study, for the first time, an artificial infection of an ex-vivo skin model with Exophiala dermatitidis was monitored microscopically and transcriptomically. Results show that Exophiala dermatitidis is able to actively grow and penetrate the skin. The analysis of the genomic and RNA-sequencing data delivers a rich and complex transcriptome where circular RNAs, fusion transcripts, long non-coding RNAs and antisense transcripts are found. Changes in transcription strongly affect pathways related to nutrients acquisition, energy metabolism, cell wall, morphological switch, and known virulence factors. The L-Tyrosine melanin pathway is specifically upregulated during infection. Moreover the production of secondary metabolites, especially alkaloids, is increased. Our study is the first that gives an insight into the complexity of the transcriptome of Exophiala dermatitidis during artificial skin infections and reveals new virulence factors.
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Affiliation(s)
- Caroline Poyntner
- Department of Biotechnology, VIBT EQ Extremophile Center, University of Natural Resources and Life Sciences Vienna, Austria
| | - Barbara Blasi
- Department of Biotechnology, VIBT EQ Extremophile Center, University of Natural Resources and Life Sciences Vienna, Austria
| | - Elsa Arcalis
- Department for Applied Genetics and Cell Biology, Molecular Plant Physiology and Crop Biotechnology, University of Natural Resources and Life Sciences Vienna, Austria
| | - Ursula Mirastschijski
- Klinikum Bremen-Mitte, Department of Plastic, Reconstructive and Aesthetic Surgery, Faculty of Biology and Chemistry, Center for Biomolecular Interactions Bremen, University Bremen Bremen, Germany
| | - Katja Sterflinger
- Department of Biotechnology, VIBT EQ Extremophile Center, University of Natural Resources and Life Sciences Vienna, Austria
| | - Hakim Tafer
- Department of Biotechnology, VIBT EQ Extremophile Center, University of Natural Resources and Life Sciences Vienna, Austria
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25
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Iron Limitation Triggers Early Egress by the Intracellular Bacterial Pathogen Legionella pneumophila. Infect Immun 2016; 84:2185-2197. [PMID: 27185787 DOI: 10.1128/iai.01306-15] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/11/2016] [Indexed: 11/20/2022] Open
Abstract
Legionella pneumophila is an intracellular bacterial pathogen that replicates in alveolar macrophages, causing a severe form of pneumonia. Intracellular growth of the bacterium depends on its ability to sequester iron from the host cell. In the L. pneumophila strain 130b, one mechanism used to acquire this essential nutrient is the siderophore legiobactin. Iron-bound legiobactin is imported by the transport protein LbtU. Here, we describe the role of LbtP, a paralog of LbtU, in iron acquisition in the L. pneumophila strain Philadelphia-1. Similar to LbtU, LbtP is a siderophore transport protein and is required for robust growth under iron-limiting conditions. Despite their similar functions, however, LbtU and LbtP do not contribute equally to iron acquisition. The Philadelphia-1 strain lacking LbtP is more sensitive to iron deprivation in vitro Moreover, LbtP is important for L. pneumophila growth within macrophages while LbtU is dispensable. These results demonstrate that LbtP plays a dominant role over LbtU in iron acquisition. In contrast, loss of both LbtP and LbtU does not impair L. pneumophila growth in the amoebal host Acanthamoeba castellanii, demonstrating a host-specific requirement for the activities of these two transporters in iron acquisition. The growth defect of the ΔlbtP mutant in macrophages is not due to alterations in growth kinetics. Instead, the absence of LbtP limits L. pneumophila replication and causes bacteria to prematurely exit the host cell. These results demonstrate the existence of a preprogrammed exit strategy in response to iron limitation that allows L. pneumophila to abandon the host cell when nutrients are exhausted.
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26
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Cianciotto NP. An update on iron acquisition by Legionella pneumophila: new pathways for siderophore uptake and ferric iron reduction. Future Microbiol 2016; 10:841-51. [PMID: 26000653 DOI: 10.2217/fmb.15.21] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Iron acquisition is critical for the growth and pathogenesis of Legionella pneumophila, the causative agent of Legionnaires' disease. L. pneumophila utilizes two main modes of iron assimilation, namely ferrous iron uptake via the FeoB system and ferric iron acquisition through the action of the siderophore legiobactin. This review highlights recent studies concerning the mechanism of legiobactin assimilation, the impact of c-type cytochromes on siderophore production, the importance of legiobactin in lung infection and a newfound role for a bacterial pyomelanin in iron acquisition. These data demonstrate that key aspects of L. pneumophila iron acquisition are significantly distinct from those of long-studied, 'model' organisms. Indeed, L. pneumophila may represent a new paradigm for a variety of other intracellular parasites, pathogens and under-studied bacteria.
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27
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Aubi O, Flydal MI, Zheng H, Skjærven L, Rekand I, Leiros HKS, Haug BE, Cianciotto NP, Martinez A, Underhaug J. Discovery of a Specific Inhibitor of Pyomelanin Synthesis in Legionella pneumophila. J Med Chem 2015; 58:8402-12. [DOI: 10.1021/acs.jmedchem.5b01589] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Oscar Aubi
- Department
of Biomedicine, University of Bergen, Bergen, Norway
| | - Marte I. Flydal
- Department
of Biomedicine, University of Bergen, Bergen, Norway
| | - Huaixin Zheng
- Department
of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois 60611, United States
| | - Lars Skjærven
- Department
of Biomedicine, University of Bergen, Bergen, Norway
| | - Illimar Rekand
- Department
of Chemistry and Centre for Pharmacy, University of Bergen, Bergen, Norway
| | - Hanna-Kirsti S. Leiros
- The
Norwegian Structural Biology Centre (NorStruct), Department of Chemistry, UiT The Arctic University of Norway, Tromsø, Norway
| | - Bengt Erik Haug
- Department
of Chemistry and Centre for Pharmacy, University of Bergen, Bergen, Norway
| | - Nicholas P. Cianciotto
- Department
of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois 60611, United States
| | - Aurora Martinez
- Department
of Biomedicine, University of Bergen, Bergen, Norway
| | - Jarl Underhaug
- Department
of Biomedicine, University of Bergen, Bergen, Norway
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Mendis N, McBride P, Faucher SP. Short-Term and Long-Term Survival and Virulence of Legionella pneumophila in the Defined Freshwater Medium Fraquil. PLoS One 2015; 10:e0139277. [PMID: 26406895 PMCID: PMC4583229 DOI: 10.1371/journal.pone.0139277] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/09/2015] [Indexed: 12/03/2022] Open
Abstract
Legionella pneumophila (Lp) is the etiological agent responsible for Legionnaires’ disease, a potentially fatal pulmonary infection. Lp lives and multiplies inside protozoa in a variety of natural and man-made water systems prior to human infection. Fraquil, a defined freshwater medium, was used as a highly reproducible medium to study the behaviour of Lp in water. Adopting a reductionist approach, Fraquil was used to study the impact of temperature, pH and trace metal levels on the survival and subsequent intracellular multiplication of Lp in Acanthamoeba castellanii, a freshwater protozoan and a natural host of Legionella. We show that temperature has a significant impact on the short- and long-term survival of Lp, but that the bacterium retains intracellular multiplication potential for over six months in Fraquil. Moreover, incubation in Fraquil at pH 4.0 resulted in a rapid decline in colony forming units, but was not detrimental to intracellular multiplication. In contrast, variations in trace metal concentrations had no impact on either survival or intracellular multiplication in amoeba. Our data show that Lp is a resilient bacterium in the water environment, remaining infectious to host cells after six months under the nutrient-deprived conditions of Fraquil.
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Affiliation(s)
- Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Peter McBride
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
| | - Sébastien P. Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University, Sainte-Anne-de-Bellevue, QC, Canada
- * E-mail:
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MavN is a Legionella pneumophila vacuole-associated protein required for efficient iron acquisition during intracellular growth. Proc Natl Acad Sci U S A 2015; 112:E5208-17. [PMID: 26330609 DOI: 10.1073/pnas.1511389112] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Iron is essential for the growth and virulence of most intravacuolar pathogens. The mechanisms by which microbes bypass host iron restriction to gain access to this metal across the host vacuolar membrane are poorly characterized. In this work, we identify a unique intracellular iron acquisition strategy used by Legionella pneumophila. The bacterial Icm/Dot (intracellular multiplication/defect in organelle trafficking) type IV secretion system targets the bacterial-derived MavN (more regions allowing vacuolar colocalization N) protein to the surface of the Legionella-containing vacuole where this putative transmembrane protein facilitates intravacuolar iron acquisition. The ΔmavN mutant exhibits a transcriptional iron-starvation signature before its growth is arrested during the very early stages of macrophage infection. This intracellular growth defect is rescued only by the addition of excess exogenous iron to the culture medium and not a variety of other metals. Consistent with MavN being a translocated substrate that plays an exclusive role during intracellular growth, the mutant shows no defect for growth in broth culture, even under severe iron-limiting conditions. Putative iron-binding residues within the MavN protein were identified, and point mutations in these residues resulted in defects specific for intracellular growth that are indistinguishable from the ΔmavN mutant. This model of a bacterial protein inserting into host membranes to mediate iron transport provides a paradigm for how intravacuolar pathogens can use virulence-associated secretion systems to manipulate and acquire host iron.
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The Legionella pneumophila Siderophore Legiobactin Is a Polycarboxylate That Is Identical in Structure to Rhizoferrin. Infect Immun 2015. [PMID: 26195554 DOI: 10.1128/iai.00808-15] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Legionella pneumophila, the agent of Legionnaires' disease, secretes a siderophore (legiobactin) that promotes bacterial infection of the lung. In past work, we determined that cytoplasmic LbtA (from Legiobactin gene A) promotes synthesis of legiobactin, inner membrane LbtB aids in export of the siderophore, and outer membrane LbtU and inner membrane LbtC help mediate ferrilegiobactin uptake and assimilation. However, the past studies examined legiobactin contained within bacterial culture supernatants. By utilizing high-pressure liquid chromatography that incorporates hydrophilic interaction-based chemistry, we have now purified legiobactin from supernatants of virulent strain 130b that is suitable for detailed chemical analysis. High-resolution mass spectrometry (MS) revealed that the molecular mass of (protonated) legiobactin is 437.140 Da. On the basis of the results obtained from both MS analysis and various forms of nuclear magnetic resonance, we found that legiobactin is composed of two citric acid residues linked by a putrescine bridge and thus is identical in structure to rhizoferrin, a polycarboxylate-type siderophore made by many fungi and several unrelated bacteria. Both purified legiobactin and rhizoferrin obtained from the fungus Cunninghamella elegans were able to promote Fe(3+) uptake by wild-type L. pneumophila as well as enhance growth of iron-starved bacteria. These results did not occur with 130b mutants lacking lbtU or lbtC, indicating that both endogenously made legiobactin and exogenously derived rhizoferrin are assimilated by L. pneumophila in an LbtU- and LbtC-dependent manner.
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Selective requirement of the shikimate pathway of Legionella pneumophila for intravacuolar growth within human macrophages but not within Acanthamoeba. Infect Immun 2015; 83:2487-95. [PMID: 25847958 DOI: 10.1128/iai.00294-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 03/26/2015] [Indexed: 11/20/2022] Open
Abstract
Legionella pneumophila utilizes the Dot/Icm type IV translocation system to proliferate within a vacuole in a wide variety of natural amoebal hosts and in alveolar macrophages of the human accidental host. Although L. pneumophila utilizes host amino acids as the main sources of carbon and energy, it is not known whether de novo synthesis of amino acids by intravacuolar L. pneumophila contributes to its nutrition. The aroB and aroE genes encode enzymes for the shikimate pathway that generates the aromatic amino acids Phe, Trp, and Tyr. Here we show the aroB and aroE mutants of L. pneumophila to be defective in growth in human monocyte-derived macrophages (hMDMs) but not in Acanthamoeba spp. The aroB and aroE mutants are severely attenuated in intrapulmonary proliferation in the A/J mouse model of Legionnaires' disease, and the defect is fully complemented by the respective wild-type alleles. The two mutants grow normally in rich media but do not grow in defined media lacking aromatic amino acids, and the growth defect is rescued by inclusion of the aromatic amino acids, which are essential for production of the pyomelanin pigment. Interestingly, supplementation of infected hMDMs with the three aromatic amino acids or with Trp alone rescues the intramacrophage defect of the aroE but not the aroB mutant. Therefore, the shikimate pathway of L. pneumophila is differentially required for optimal growth within human macrophages, which are auxotrophic for Trp and Phe, but is dispensable for growth within the Acanthamoeba spp. that synthesize the aromatic amino acids.
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Isolation and identification of a gene encoding 4-hydroxyphenylpyruvate dioxygenase from the red-brown pigment-producing bacterium Alteromonas stellipolaris LMG 21856. Folia Microbiol (Praha) 2015; 60:309-16. [DOI: 10.1007/s12223-015-0386-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 03/08/2015] [Indexed: 01/26/2023]
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Factors influencing persistence of Legionella pneumophila serogroup 1 in laboratory cocultures. BMC Microbiol 2014; 14:249. [PMID: 25277877 PMCID: PMC4195868 DOI: 10.1186/s12866-014-0249-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/17/2014] [Indexed: 12/03/2022] Open
Abstract
Background Risk for infections from Legionella pneumophila for immunocompromised individuals increases greatly when this species is present within the biofilm of the water distribution systems of hospitals or other health facilities. Multiplication and persistence of Legionella may dependent also upon planktonic growth in alternative to sessile growth. Here we compared the persistence of L. pneumophila serogroup 1 in experimental planktonic co-cultures subsided with iron, Pseudomonas aeruginosa and other non Legionella bacteria (quantified as Heterotrophic Plate Count, HPC at 37°C), isolated from drinking water sources of a large hospital. Results Concentrations of L. pneumophila showed a decreasing pattern with incubation time in all co-cultures, the degree of reduction depending on the experimental treatment. In co-cultures with added P. aeruginosa, no L. pneumophila was detectable already after 4 days of incubation. In contrast in co-cultures without P. aeruginosa, HPC but not iron were significant factors in explaining the pattern of L. pneumophila, although the HPC effect was different according to the incubation time (HPC x time interaction, p < 0.01). Conclusions Our results highlight the need of controlling for both HPC and metal constituents of the water systems of buildings used by individuals at particular risk to the effects of Legionella exposure.
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Portier E, Zheng H, Sahr T, Burnside DM, Mallama C, Buchrieser C, Cianciotto NP, Héchard Y. IroT/mavN, a new iron-regulated gene involved in Legionella pneumophila virulence against amoebae and macrophages. Environ Microbiol 2014; 17:1338-50. [PMID: 25141909 DOI: 10.1111/1462-2920.12604] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 08/14/2014] [Indexed: 10/24/2022]
Abstract
Legionella pneumophila is a pathogenic bacterium commonly found in water. Eventually, it could be transmitted to humans via inhalation of contaminated aerosols. Iron is known as a key requirement for the growth of L. pneumophila in the environment and within its hosts. Many studies were performed to understand iron utilization by L. pneumophila but no global approaches were conducted. In this study, transcriptomic analyses were performed, comparing gene expression in L. pneumophila in standard versus iron restricted conditions. Among the regulated genes, a newly described one, lpp_2867, was highly induced in iron-restricted conditions. Mutants lacking this gene in L. pneumophila were not affected in siderophore synthesis or utilization. On the contrary, they were defective for growth on iron-depleted solid media and for ferrous iron uptake. A sequence analysis predicts that Lpp_2867 is a membrane protein, suggesting that it is involved in ferrous iron transport. We thus named it IroT, for iron transporter. Infection assays showed that the mutants are highly impaired in intracellular growth within their environmental host Acanthamoeba castellanii and human macrophages. Taken together, our results show that IroT is involved, directly or indirectly, in ferrous iron transport and is a key virulence factor for L. pneumophila.
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Affiliation(s)
- Emilie Portier
- Laboratoire Ecologie et Biologie des Interactions, UMR CNRS 7267, Equipe Microbiologie de l'Eau, Université de Poitiers, Poitiers, France
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Manske C, Hilbi H. Metabolism of the vacuolar pathogen Legionella and implications for virulence. Front Cell Infect Microbiol 2014; 4:125. [PMID: 25250244 PMCID: PMC4158876 DOI: 10.3389/fcimb.2014.00125] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/20/2014] [Indexed: 11/17/2022] Open
Abstract
Legionella pneumophila is a ubiquitous environmental bacterium that thrives in fresh water habitats, either as planktonic form or as part of biofilms. The bacteria also grow intracellularly in free-living protozoa as well as in mammalian alveolar macrophages, thus triggering a potentially fatal pneumonia called “Legionnaires' disease.” To establish its intracellular niche termed the “Legionella-containing vacuole” (LCV), L. pneumophila employs a type IV secretion system and translocates ~300 different “effector” proteins into host cells. The pathogen switches between two distinct forms to grow in its extra- or intracellular niches: transmissive bacteria are virulent for phagocytes, and replicative bacteria multiply within their hosts. The switch between these forms is regulated by different metabolic cues that signal conditions favorable for replication or transmission, respectively, causing a tight link between metabolism and virulence of the bacteria. Amino acids represent the prime carbon and energy source of extra- or intracellularly growing L. pneumophila. Yet, the genome sequences of several Legionella spp. as well as transcriptome and proteome data and metabolism studies indicate that the bacteria possess broad catabolic capacities and also utilize carbohydrates such as glucose. Accordingly, L. pneumophila mutant strains lacking catabolic genes show intracellular growth defects, and thus, intracellular metabolism and virulence of the pathogen are intimately connected. In this review we will summarize recent findings on the extra- and intracellular metabolism of L. pneumophila using genetic, biochemical and cellular microbial approaches. Recent progress in this field sheds light on the complex interplay between metabolism, differentiation and virulence of the pathogen.
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Affiliation(s)
- Christian Manske
- Max von Pettenkofer Institute, Faculty of Medicine, Ludwig-Maximilians University Munich, Germany
| | - Hubert Hilbi
- Max von Pettenkofer Institute, Faculty of Medicine, Ludwig-Maximilians University Munich, Germany ; Institute of Medical Microbiology, Faculty of Medicine, University of Zürich Zürich, Switzerland
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Greene GH, McGary KL, Rokas A, Slot JC. Ecology drives the distribution of specialized tyrosine metabolism modules in fungi. Genome Biol Evol 2014; 6:121-32. [PMID: 24391152 PMCID: PMC3914699 DOI: 10.1093/gbe/evt208] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Gene clusters encoding accessory or environmentally specialized metabolic pathways likely play a significant role in the evolution of fungal genomes. Two such gene clusters encoding enzymes associated with the tyrosine metabolism pathway (KEGG #00350) have been identified in the filamentous fungus Aspergillus fumigatus. The l-tyrosine degradation (TD) gene cluster encodes a functional module that facilitates breakdown of the phenolic amino acid, l-tyrosine through a homogentisate intermediate, but is also involved in the production of pyomelanin, a fungal pathogenicity factor. The gentisate catabolism (GC) gene cluster encodes a functional module likely involved in phenolic compound degradation, which may enable metabolism of biphenolic stilbenes in multiple lineages. Our investigation of the evolution of the TD and GC gene clusters in 214 fungal genomes revealed spotty distributions partially shaped by gene cluster loss and horizontal gene transfer (HGT). Specifically, a TD gene cluster shows evidence of HGT between the extremophilic, melanized fungi Exophiala dermatitidis and Baudoinia compniacensis, and a GC gene cluster shows evidence of HGT between Sordariomycete and Dothideomycete grass pathogens. These results suggest that the distribution of specialized tyrosine metabolism modules is influenced by both the ecology and phylogeny of fungal species.
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NTBC treatment of the pyomelanogenic Pseudomonas aeruginosa clinical isolate PA1111 inhibits pigment production and increases sensitivity to oxidative stress. Curr Microbiol 2014; 69:343-8. [PMID: 24801336 PMCID: PMC4113677 DOI: 10.1007/s00284-014-0593-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/01/2014] [Indexed: 10/26/2022]
Abstract
Pyomelanin is a brown/black extracellular pigment with antioxidant and iron acquisition properties that is produced by a number of different bacteria. Production of pyomelanin in Pseudomonas aeruginosa contributes to increased resistance to oxidative stress and persistence in chronic infections. We demonstrate that pyomelanin production can be inhibited by 2-[2-nitro-4-(trifluoromethyl) benzoyl]-1,3-cyclohexanedione (NTBC). This treatment increases sensitivity of pyomelanogenic P. aeruginosa strains to oxidative stress, without altering the growth rate or resistance to aminoglycosides. As such, NTBC has potential to function as an anti-virulence factor in treating pyomelanogenic bacterial infections.
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Fonseca MV, Swanson MS. Nutrient salvaging and metabolism by the intracellular pathogen Legionella pneumophila. Front Cell Infect Microbiol 2014; 4:12. [PMID: 24575391 PMCID: PMC3920079 DOI: 10.3389/fcimb.2014.00012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 01/23/2014] [Indexed: 11/13/2022] Open
Abstract
The Gram-negative bacterium Legionella pneumophila is ubiquitous in freshwater environments as a free-swimming organism, resident of biofilms, or parasite of protozoa. If the bacterium is aerosolized and inhaled by a susceptible human host, it can infect alveolar macrophages and cause a severe pneumonia known as Legionnaires' disease. A sophisticated cell differentiation program equips L. pneumophila to persist in both extracellular and intracellular niches. During its life cycle, L. pneumophila alternates between at least two distinct forms: a transmissive form equipped to infect host cells and evade lysosomal degradation, and a replicative form that multiplies within a phagosomal compartment that it has retooled to its advantage. The efficient changeover between transmissive and replicative states is fundamental to L. pneumophila's fitness as an intracellular pathogen. The transmission and replication programs of L. pneumophila are governed by a number of metabolic cues that signal whether conditions are favorable for replication or instead trigger escape from a spent host. Several lines of experimental evidence gathered over the past decade establish strong links between metabolism, cellular differentiation, and virulence of L. pneumophila. Herein, we focus on current knowledge of the metabolic components employed by intracellular L. pneumophila for cell differentiation, nutrient salvaging and utilization of host factors. Specifically, we highlight the metabolic cues that are coupled to bacterial differentiation, nutrient acquisition systems, and the strategies utilized by L. pneumophila to exploit host metabolites for intracellular replication.
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Affiliation(s)
- Maris V Fonseca
- Science and Mathematics Division, Monroe County Community College Monroe, MI, USA
| | - Michele S Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School Ann Arbor, MI, USA
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