1
|
Bing H, Qi C, Gu J, Zhao T, Yu X, Cai Y, Zhang Y, Li A, Wang X, Zhao J, Xiang W. Isolation and identification of NEAU-CP5: A seed-endophytic strain of B. velezensis that controls tomato bacterial wilt. Microb Pathog 2024; 192:106707. [PMID: 38777241 DOI: 10.1016/j.micpath.2024.106707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 04/29/2024] [Accepted: 05/19/2024] [Indexed: 05/25/2024]
Abstract
Bacterial wilt of tomato caused by Ralstonia solanacearum is a critical soilborne disease that drastically reduces yield. In the current study, an endophytic strain NEAU-CP5 with strong antagonistic activity against R. solanacearum was isolated from tomato seeds and characterized. The strain was identified as Bacillus velezensis based on 16S rRNA gene and whole genome sequence analysis. NEAU-CP5 can secrete amylase, protease, and cellulase, and also produce known antibacterial metabolites, including cyclo (leucylprolyl), cyclo (phenylalanyl-prolyl), cyclo (Pro-Gly), 3-benzyl-2,5-piperazinedione, pentadecanoic acid, eicosane, 2-methyoic acid, isovaleric acid, dibuty phthalate, and esters of fatty acids (HFDU), which may be responsible for its strong antibacterial activity. Fourteen gene clusters associated with antibacterial properties were also identified in the whole genome sequence of NEAU-CP5. Pot experiment demonstrated that the application of 108 CFU/mL NEAU-CP5 on tomato plants significantly reduced the incidence of tomato bacterial wilt by 68.36 ± 1.67 %. NEAU-CP5 also increased the activity of defense-related enzymes (CAT, POD, PPO, SOD, and PAL) in tomato plants. This is the first report of an effective control of bacterial wilt on tomato plants by B. velezensis and highlights the potential of NEAU-CP5 as a potential biocontrol agent for the management of tomato bacterial wilt.
Collapse
Affiliation(s)
- Hui Bing
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Cuiping Qi
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Jinzhao Gu
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Tianxin Zhao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Xiaoyan Yu
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Yang Cai
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Yance Zhang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Ailin Li
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China
| | - Xiangjing Wang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, PR China
| | - Junwei Zhao
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China.
| | - Wensheng Xiang
- Key Laboratory of Agricultural Microbiology of Heilongjiang Province, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, PR China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, PR China.
| |
Collapse
|
2
|
Freitas M, Araujo B, Soares R, Gouveia J, Costa M, Gouveia G. Detection of Fur, AmoA and pvcAB genes in Aeromonas hydrophila isolated from aquatic organisms and impact on bacterial growth under different iron concentrations. ARQ BRAS MED VET ZOO 2022. [DOI: 10.1590/1678-4162-12491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
ABSTRACT Infection caused by Aeromonas brings great harm to fish farming. Among the factors associated with bacterial pathogenesis, iron uptake can contribute to the survival and virulence of bacteria within hosts. The aim of this study was to check the presence of genes related to iron uptake in Aeromonas hydrophila deriving from aquatic organisms in the São Francisco Valley and associate the presence of these genes with the ability to grow in media containing different concentrations of iron. The DNAs of 41 isolates were extracted and used in PCRs to verify the presence of the Fur, AmoA and pvcAB genes related to iron uptake. The growth of the isolates belonging to different genetic profiles was verified in culture media containing different iron concentrations. Two isolates were positive for the presence of the Fur gene, seven for the AmoA gene and two for the pvcAB gene. The growth test showed that the low availability of iron did not interfere in the growth of the isolates, nor in the isolate that did not contain any of the genes evaluated in this study, suggesting that the iron uptake’s mechanisms of the tested isolates may be related to other genes and proteins.
Collapse
Affiliation(s)
- M.R. Freitas
- Universidade Federal do Vale do São Francisco, Brazil
| | - B.N. Araujo
- Universidade Federal do Vale do São Francisco, Brazil
| | - R.A.N. Soares
- Universidade Federal do Vale do São Francisco, Brazil
| | | | - M.M. Costa
- Universidade Federal do Vale do São Francisco, Brazil
| | - G.V. Gouveia
- Universidade Federal do Vale do São Francisco, Brazil
| |
Collapse
|
3
|
Balado M, Souto A, Vences A, Careaga VP, Valderrama K, Segade Y, Rodríguez J, Osorio CR, Jiménez C, Lemos ML. Two Catechol Siderophores, Acinetobactin and Amonabactin, Are Simultaneously Produced by Aeromonas salmonicida subsp. salmonicida Sharing Part of the Biosynthetic Pathway. ACS Chem Biol 2015; 10:2850-60. [PMID: 26463084 DOI: 10.1021/acschembio.5b00624] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The iron uptake mechanisms based on siderophore synthesis used by the fish pathogen Aeromonas salmonicida subsp. salmonicida are still not completely understood, and the precise structure of the siderophore(s) is unknown. The analysis of genome sequences revealed that this bacterium possesses two gene clusters putatively involved in the synthesis of siderophores. One cluster is a candidate to encode the synthesis of acinetobactin, the siderophore of the human pathogen Acinetobacter baumannii, while the second cluster shows high similarity to the genes encoding amonabactin synthesis in Aeromonas hydrophila. Using a combination of genomic analysis, mutagenesis, biological assays, chemical purification, and structural determination procedures, here we demonstrate that most A. salmonicida subsp. salmonicida strains produce simultaneously the two siderophores, acinetobactin and amonabactin. Interestingly, the synthesis of both siderophores relies on a single copy of the genes encoding the synthesis of the catechol moiety (2,3-dihydroxybenzoic acid) and on one encoding a phosphopantetheinyl transferase. These genes are present only in the amonabactin cluster, and a single mutation in any of them abolishes production of both siderophores. We could also demonstrate that some strains, isolated from fish raised in seawater, produce only acinetobactin since they present a deletion in the amonabactin biosynthesis gene amoG. Our study represents the first evidence of simultaneous production of acinetobactin and amonabactin by a bacterial pathogen and reveals the plasticity of bacterial genomes and biosynthetic pathways. The fact that the same siderophore is produced by unrelated pathogens highlights the importance of these systems and their interchangeability between different bacteria.
Collapse
Affiliation(s)
- Miguel Balado
- Department
of Microbiology and Parasitology, Institute of Aquaculture, Universidade de Santiago de Compostela, Campus Sur, Santiago de Compostela 15782, Spain
| | - Alba Souto
- Centro
de Investigacións Científicas Avanzadas (CICA), Departamento
de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain
| | - Ana Vences
- Department
of Microbiology and Parasitology, Institute of Aquaculture, Universidade de Santiago de Compostela, Campus Sur, Santiago de Compostela 15782, Spain
| | - Valeria P. Careaga
- Centro
de Investigacións Científicas Avanzadas (CICA), Departamento
de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain
| | - Katherine Valderrama
- Centro
de Investigacións Científicas Avanzadas (CICA), Departamento
de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain
| | - Yuri Segade
- Centro
de Investigacións Científicas Avanzadas (CICA), Departamento
de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain
| | - Jaime Rodríguez
- Centro
de Investigacións Científicas Avanzadas (CICA), Departamento
de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain
| | - Carlos R. Osorio
- Department
of Microbiology and Parasitology, Institute of Aquaculture, Universidade de Santiago de Compostela, Campus Sur, Santiago de Compostela 15782, Spain
| | - Carlos Jiménez
- Centro
de Investigacións Científicas Avanzadas (CICA), Departamento
de Química Fundamental, Facultade de Ciencias, Universidade da Coruña, 15071 A Coruña, Spain
| | - Manuel L. Lemos
- Department
of Microbiology and Parasitology, Institute of Aquaculture, Universidade de Santiago de Compostela, Campus Sur, Santiago de Compostela 15782, Spain
| |
Collapse
|
4
|
Ebanks RO, Goguen M, Knickle L, Dacanay A, Leslie A, Ross NW, Pinto DM. Analysis of a ferric uptake regulator (Fur) knockout mutant in Aeromonas salmonicida subsp. salmonicida. Vet Microbiol 2013; 162:831-841. [DOI: 10.1016/j.vetmic.2012.10.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 10/03/2012] [Accepted: 10/05/2012] [Indexed: 10/27/2022]
|
5
|
Nisr RB, Moody AJ, Gilpin ML. Screening microorganisms for insulin binding reveals binding by Burkholderia multivorans and Burkholderia cenocepacia and novel attachment of insulin to Aeromonas salmonicida via the A-layer. FEMS Microbiol Lett 2011; 328:93-9. [PMID: 22171975 DOI: 10.1111/j.1574-6968.2011.02484.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 12/02/2011] [Accepted: 12/06/2011] [Indexed: 11/27/2022] Open
Abstract
Exposure to microorganisms is considered an environmental factor that can contribute to Type 1 diabetes. Insulin-binding proteins (IBPs) on microorganisms may induce production of antibodies that can react with the human insulin receptor (HIR) with possible consequences in developing a diabetic autoimmune response against HIR and insulin. The interaction of insulin with microorganisms was studied by screening 45 microbial species for their ability to bind insulin. Binding assays were performed using labelled insulin to identify insulin-binding components on the microorganisms. Burkholderia multivorans and Burkholderia cenocepacia isolated from patients with cystic fibrosis (CF) and the fish pathogen Aeromonas salmonicida were the only strains of those tested, which showed insulin-binding components on their cell surfaces. Further work with A. salmonicida suggested that the insulin-binding activity of A. salmonicida is due to the A-layer. A mutant of A. salmonicida lacking the A-layer showed binding, but at a much reduced rate suggesting another insulin-binding component in addition to the high affinity of the A-protein. Soluble protein lysates were subjected to Western ligand blotting using peroxidase-labelled insulin to detect IBPs. Two positive IBPs were apparent at approximately 30 and 20 kDa in lysates from Burkholderia strains, but no IBP was detected in A. salmonicida lysates.
Collapse
Affiliation(s)
- Raid B Nisr
- Centre for Research in Translational Biomedicine, School of Biomedical and Biological Sciences, University of Plymouth, Plymouth, UK
| | | | | |
Collapse
|
6
|
Najimi M, Lemos ML, Osorio CR. Identification of iron regulated genes in the fish pathogen Aeromonas salmonicida subsp. salmonicida: genetic diversity and evidence of conserved iron uptake systems. Vet Microbiol 2008; 133:377-82. [PMID: 18774242 DOI: 10.1016/j.vetmic.2008.07.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 07/02/2008] [Accepted: 07/16/2008] [Indexed: 11/30/2022]
Abstract
In this study we applied the Fur titration assay (FURTA) to isolate iron regulated genes in Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis in fish. We have identified genes for siderophore biosynthesis and for ferri-siderophore transport, some of which have been previously described in this species. A gene for a hitherto uncharacterized functional hemin receptor HutE was identified, but its inactivation did not affect significantly the use of hemin as sole iron source, suggesting that redundant genes encoding hemin receptors exist in the A. salmonicida genome. Additional FURTA positive clones contained genes encoding a Flavoprotein, a transcriptional regulator protein, a DNA binding protein Fis, as well as genes encoding putative DapD and Flp/Fap-pilin proteins. A screening of gene distribution demonstrated that all the analyzed strains shared genes for siderophore biosynthesis and transport and for heme utilization, indicating that these two systems of iron acquisition are a conserved trait in this subspecies, whereas other genes are not common to all the isolates. Thus, the Fur regulon of A. salmonicida subsp. salmonicida includes both conserved and differentially occurring genes, suggesting that the genetic diversity within this fish pathogen might be higher than expected.
Collapse
Affiliation(s)
- Mohsen Najimi
- Department of Microbiology and Parasitology, University of Santiago de Compostela, Santiago de Compostela 15782, Spain.
| | | | | |
Collapse
|
7
|
Najimi M, Lemos ML, Osorio CR. Identification of heme uptake genes in the fish pathogen Aeromonas salmonicida subsp. salmonicida. Arch Microbiol 2008; 190:439-49. [PMID: 18535817 DOI: 10.1007/s00203-008-0391-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2008] [Revised: 04/30/2008] [Accepted: 05/13/2008] [Indexed: 10/22/2022]
Abstract
Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis in fish, can use heme as the sole iron source. We applied the Fur Titration Assay to isolate a cluster including six genes hutAZXBCD that showed similarity to heme uptake genes of other Gram-negative bacteria, and three genes orf123 of unknown function. The spatial organization of these nine genes, arranged in five transcriptional units, was similar to that of a homologous cluster in A. hydrophila. When a TonB system was provided, this cluster allowed Escherichia coli 101ESD (an ent mutant, unable to synthesize enterobactin) to utilize hemin and hemoglobin as iron sources. Mutation of hutB, a gene that encodes a predicted periplasmic hemin-binding protein, caused a drastic defect in the ability of A. salmonicida to grow with hemin as unique source of iron. Interestingly, a mutant for hutA gene (encoding the outer membrane hemin receptor) showed initially a reduced ability to grow with hemin as sole iron source, but after 24 h it achieved growth levels similar to parental strain. Thus mutation of hutA could not abolish the growth with hemin as iron source, suggesting that redundant outer membrane heme transport functions might be encoded in the A. salmonicida genome.
Collapse
Affiliation(s)
- Mohsen Najimi
- Department of Microbiology and Parasitology, Institute of Aquaculture and Faculty of Biology, University of Santiago de Compostela, 15782 Santiago de Compostela, Galicia, Spain
| | | | | |
Collapse
|
8
|
Identification of siderophore biosynthesis genes essential for growth of Aeromonas salmonicida under iron limitation conditions. Appl Environ Microbiol 2008; 74:2341-8. [PMID: 18296539 DOI: 10.1128/aem.02728-07] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aeromonas salmonicida subsp. salmonicida, the etiological agent of furunculosis in fish, produces a catechol-type siderophore under iron-limiting conditions. In this study, the Fur titration assay (FURTA) was used to identify a cluster of six genes, asbG, asbF, asbD, asbC, asbB, and asbI, encoding proteins similar to components of the siderophore biosynthetic machinery in other bacteria. Reverse transcriptase PCR analyses showed that this cluster consists of four iron-regulated transcriptional units. Mutants with deletions in either asbD (encoding a multidomain nonribosomal peptide synthetase), asbG (encoding a histidine decarboxylase), or asbC (encoding a predicted histamine monooxygenase) did not grow under iron-limiting conditions and did not produce siderophores. Growth of the DeltaasbG strain under iron starvation conditions was restored by addition of histamine, suggesting that the siderophore in this species could contain a histamine-derived moiety. None of the mutants could grow in the presence of transferrin, indicating that A. salmonicida uses the catechol-type siderophore for removal of iron from transferrin rather than relying on a receptor for this iron-binding protein. All 18 A. salmonicida strains analyzed by DNA probe hybridization were positive in tests for the presence of the asbD gene, and all of them promoted the growth of asbD, asbG, and asbC mutants, suggesting that this siderophore-mediated iron uptake system is conserved among A. salmonicida isolates. This study provides the first description of siderophore biosynthesis genes in this fish pathogen, and the results demonstrate that the asbD, asbG, and asbC genes are necessary for the production of a catecholate siderophore that is essential for the growth of A. salmonicida under iron limitation conditions.
Collapse
|
9
|
Contribution of type IV pili to the virulence of Aeromonas salmonicida subsp. salmonicida in Atlantic salmon (Salmo salar L.). Infect Immun 2008; 76:1445-55. [PMID: 18212071 DOI: 10.1128/iai.01019-07] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Aeromonas salmonicida subsp. salmonicida, a bacterial pathogen of Atlantic salmon, has no visible pili, yet its genome contains genes for three type IV pilus systems. One system, Tap, is similar to the Pseudomonas aeruginosa Pil system, and a second, Flp, resembles the Actinobacillus actinomycetemcomitans Flp pilus, while the third has homology to the mannose-sensitive hemagglutinin pilus of Vibrio cholerae. The latter system is likely nonfunctional since eight genes, including the gene encoding the main pilin subunit, are deleted compared with the orthologous V. cholerae locus. The first two systems were characterized to investigate their expression and role in pathogenesis. The pili of A. salmonicida subsp. salmonicida were imaged using atomic force microscopy and Tap- and Flp-overexpressing strains. The Tap pili appeared to be polar, while the Flp pili appeared to be peritrichous. Strains deficient in tap and/or flp were used in live bacterial challenges of Atlantic salmon, which showed that the Tap pilus made a moderate contribution to virulence, while the Flp pilus made little or no contribution. Delivery of the tap mutant by immersion resulted in reduced cumulative morbidity compared with the cumulative morbidity observed with the wild-type strain; however, delivery by intraperitoneal injection resulted in cumulative morbidity similar to that of the wild type. Unlike the pili of other piliated bacterial pathogens, A. salmonicida subsp. salmonicida type IV pili are not absolutely required for virulence in Atlantic salmon. Significant differences in the behavior of the two mutant strains indicated that the two pilus systems are not redundant.
Collapse
|
10
|
Dacanay A, Knickle L, Solanky KS, Boyd JM, Walter JA, Brown LL, Johnson SC, Reith M. Contribution of the type III secretion system (TTSS) to virulence of Aeromonas salmonicida subsp. salmonicida. Microbiology (Reading) 2006; 152:1847-1856. [PMID: 16735747 DOI: 10.1099/mic.0.28768-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recently described type III secretion system (TTSS) of Aeromonas salmonicida subsp. salmonicida has been linked to virulence in salmonids. In this study, three TTSS effector genes, aexT, aopH or aopO, were inactivated by deletion, as was ascC, the gene encoding the outer-membrane pore of the secretion apparatus. Effects on virulence were assayed by live challenge of Atlantic salmon (Salmo salar). The ΔascC mutant strain was avirulent by both intraperitoneal (i.p.) injection and immersion, did not appear to establish a clinically inapparent infection and did not confer protection from subsequent rechallenge with the parental strain. 1H NMR spectroscopy-based metabolite profiling of plasma from all fish showed significant differences in the metabolite profiles between the animals exposed to the parental strain or ΔascC. The experimental infection by immersion with ΔaopO was indistinguishable from that of the parental strain, that of ΔaexT was delayed, whilst the virulence of ΔaopH was reduced significantly but not abolished. By i.p. injection, ΔaexT, ΔaopH and ΔaopO caused an experimental disease indistinguishable from that of the parental strain. These data demonstrate that while the TTSS is absolutely essential for virulence of A. salmonicida subsp. salmonicida in Atlantic salmon, removal of individual effectors has little influence on virulence but has a significant effect on colonization. The ΔascC i.p. injection data also suggest that in addition to host invasion there is a second step in A. salmonicida pathogenesis that requires an active TTSS.
Collapse
Affiliation(s)
- A Dacanay
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - L Knickle
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - K S Solanky
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - J M Boyd
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - J A Walter
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - L L Brown
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - S C Johnson
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| | - M Reith
- National Research Council of Canada Institute for Marine Biosciences, 1411 Oxford Street, Halifax, Nova Scotia, Canada
| |
Collapse
|
11
|
Shanmuganathan A, Avery SV, Willetts SA, Houghton JE. Copper-induced oxidative stress inSaccharomyces cerevisiaetargets enzymes of the glycolytic pathway. FEBS Lett 2003; 556:253-9. [PMID: 14706859 DOI: 10.1016/s0014-5793(03)01428-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Increased cellular levels of reactive oxygen species are known to arise during exposure of organisms to elevated metal concentrations, but the consequences for cells in the context of metal toxicity are poorly characterized. Using two-dimensional gel electrophoresis, combined with immunodetection of protein carbonyls, we report here that exposure of the yeast Saccharomyces cerevisiae to copper causes a marked increase in cellular protein carbonyl levels, indicative of oxidative protein damage. The response was time dependent, with total-protein oxidation peaking approximately 15 min after the onset of copper treatment. Moreover, this oxidative damage was not evenly distributed among the expressed proteins of the cell. Rather, in a similar manner to peroxide-induced oxidative stress, copper-dependent protein carbonylation appeared to target glycolytic pathway and related enzymes, as well as heat shock proteins. Oxidative targeting of these and other enzymes was isoform-specific and, in most cases, was also associated with a decline in the proteins' relative abundance. Our results are consistent with a model in which copper-induced oxidative stress disables the flow of carbon through the preferred glycolytic pathway, and promotes the production of glucose-equivalents within the pentose phosphate pathway. Such re-routing of the metabolic flux may serve as a rapid-response mechanism to help cells counter the damaging effects of copper-induced oxidative stress.
Collapse
Affiliation(s)
- Anupama Shanmuganathan
- Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA
| | | | | | | |
Collapse
|
12
|
Holmstrøm K, Gram L. Elucidation of the Vibrio anguillarum genetic response to the potential fish probiont Pseudomonas fluorescens AH2, using RNA-arbitrarily primed PCR. J Bacteriol 2003; 185:831-42. [PMID: 12533458 PMCID: PMC142799 DOI: 10.1128/jb.185.3.831-842.2003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Accepted: 10/30/2002] [Indexed: 11/20/2022] Open
Abstract
The antagonistic interaction between a potential fish probiont, Pseudomonas fluorescens strain AH2, and its target organism, Vibrio anguillarum, was investigated by studying the genetic response of the target organism when it was exposed to the antagonist. We compared the differential display of arbitrarily PCR-amplified gene transcripts in V. anguillarum serotype O1 when it was exposed to AH2 supernatant with the display of transcripts in nonexposed control cultures. Growth of V. anguillarum was immediately arrested when the organism was exposed to 50% (vol/vol) AH2 supernatant. A total of 10 potentially differentially expressed transcripts were identified. Among these we identified a gene homologous to rpoS that was induced in a dose-dependent manner when V. anguillarum was cultured in media supplemented with sterile filtered supernatant from AH2. rpoS was also induced when growth was arrested with the iron chelator 2,2-dipyridyl. A chromosomal transcript homologous to vibE that participates in vibriobactin synthesis in Vibrio cholerae was also upregulated during AH2 exposure. This transcript could represent a functionally active gene in V. anguillarum involved in biosynthesis of anguibactin or another V. anguillarum siderophore. On the pJM1 plasmid of V. anguillarum serotype O1, a pseudogene designated open reading frame E (ORF E) that contains a frameshift mutation was previously identified. The gene homologous to vibE identified in this study, interestingly, also has significant homology to ORF E on the amino acid level and does not possess the frameshift mutation. Thus, the chromosomally encoded vibE homologue could fulfil the role of the inactive plasmid-encoded ORF E pseudogene. Addition of Fe(3+) to the system eliminated the growth arrest, and the genes homologous to rpoS and vibE were not induced. To our knowledge, this is the first study linking rpoS induction to iron starvation. Taken together, the results of this study suggest that a major part of the antagonistic property exhibited by strain AH2 is caused by the ability of siderophores in the supernatant to efficiently chelate iron, which results in instant iron deprivation of the pathogen V. anguillarum and complete growth arrest.
Collapse
Affiliation(s)
- Kim Holmstrøm
- Biotechnological Institute, Department of Molecular Characterization, Kogle Allé 2, DK-2970 Hørsholm, Denmark.
| | | |
Collapse
|