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Li X, Zhong Y, Zhao C. Trypsin Binding with Copper Ions Scavenges Superoxide: Molecular Dynamics-Based Mechanism Investigation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15010139. [PMID: 29342974 PMCID: PMC5800238 DOI: 10.3390/ijerph15010139] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/27/2017] [Accepted: 01/07/2018] [Indexed: 12/18/2022]
Abstract
Trypsin is a serine protease, which has been proved to be a novel superoxide scavenger. The burst of superoxide induced by polychlorinated biphenyls can be impeded by trypsin in both wild type and sod knockout mutants of Escherichia coli. The experimental results demonstrated that the activities of superoxide scavenging of trypsin were significantly accelerated by Cu ions. Also, with the addition of Cu ions, a new β-sheet (β7) transited from a random coil in the Cu(II)-trypsin (TP) system, which was favorable for the formation of more contacts with other sheets of trypsin. Residue–residue network analysis and the porcupine plots proved that the Cu ion in trypsin strengthened some native interactions among residues, which ultimately resulted in much greater stability of the Cu(II)-TP system. Moreover, compact and stable trypsin structures with Cu ions might be responsible for significantly provoking the activity of superoxide scavenging.
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Affiliation(s)
- Xin Li
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China.
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, Lanzhou University, Lanzhou 730000, China.
| | - Yongliang Zhong
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, China.
| | - Chunyan Zhao
- School of Pharmacy, Lanzhou University, Lanzhou 730000, China.
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2
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Trypsin Slows the Aging of Mice due to Its Novel Superoxide Scavenging Activity. Appl Biochem Biotechnol 2016; 181:1549-1560. [DOI: 10.1007/s12010-016-2301-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/20/2016] [Indexed: 01/08/2023]
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3
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Gade A, Adams J, Britt DW, Shen FA, McLean JE, Jacobson A, Kim YC, Anderson AJ. Ag nanoparticles generated using bio-reduction and -coating cause microbial killing without cell lysis. Biometals 2016; 29:211-23. [DOI: 10.1007/s10534-015-9906-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 12/17/2015] [Indexed: 12/11/2022]
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4
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Li X, Dong S, Yao Y, Shi W, Wu M, Xu H. Inoculation of bacteria for the bioremediation of heavy metals contaminated soil by Agrocybe aegerita. RSC Adv 2016. [DOI: 10.1039/c6ra11767h] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The combination of mushrooms and bacteria was used as a novel technique to remediate soils polluted by heavy metals.
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Affiliation(s)
- Xue Li
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education)
- College of Life Sciences
- Sichuan University
- Chengdu
- China
| | - Shunwen Dong
- Industrial Crop Research Institute of Sichuan Academy of Agricultural Sciences
- Chengdu
- China
| | - Yuan Yao
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education)
- College of Life Sciences
- Sichuan University
- Chengdu
- China
| | - Wenjin Shi
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education)
- College of Life Sciences
- Sichuan University
- Chengdu
- China
| | - Minghui Wu
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education)
- College of Life Sciences
- Sichuan University
- Chengdu
- China
| | - Heng Xu
- Key Laboratory of Bio-resources and Eco-environment (Ministry of Education)
- College of Life Sciences
- Sichuan University
- Chengdu
- China
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5
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Basu Roy A, Sauer K. Diguanylate cyclase NicD-based signalling mechanism of nutrient-induced dispersion by Pseudomonas aeruginosa. Mol Microbiol 2014; 94:771-93. [PMID: 25243483 DOI: 10.1111/mmi.12802] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2014] [Indexed: 01/15/2023]
Abstract
Dispersion enables the transition from the biofilm to the planktonic growth state in response to various cues. While several Pseudomonas aeruginosa proteins, including BdlA and the c-di-GMP phosphodiesterases DipA, RbdA, and NbdA, have been shown to be required for dispersion to occur, little is known about dispersion cue sensing and the signalling translating these cues into the modulation c-di-GMP levels to enable dispersion. Using glutamate-induced dispersion as a model, we report that dispersion-inducing nutrient cues are sensed via an outside-in signalling mechanism by the diguanylate cyclase NicD belonging to a family of seven transmembrane (7TM) receptors. NicD directly interacts with BdlA and the phosphodiesterase DipA, with NicD, BdlA, and DipA being part of the same pathway required for dispersion. Glutamate sensing by NicD results in NicD dephosphorylation and increased cyclase activity. Active NicD contributes to the non-processive proteolysis and activation of BdlA via phosphorylation and temporarily elevated c-di-GMP levels. BdlA, in turn, activates DipA, resulting in the overall reduction of c-di-GMP levels. Our results provide a basis for understanding the signalling mechanism based on NicD to induce biofilm dispersion that may be applicable to various biofilm-forming species and may have implications for the control of biofilm-related infections.
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Affiliation(s)
- Ankita Basu Roy
- Department of Biological Sciences, Binghamton University, 85 Murray Hill Road, Binghamton, NY, 13902, USA
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6
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The fatty acid signaling molecule cis-2-decenoic acid increases metabolic activity and reverts persister cells to an antimicrobial-susceptible state. Appl Environ Microbiol 2014; 80:6976-91. [PMID: 25192989 DOI: 10.1128/aem.01576-14] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Persister cells, which are tolerant to antimicrobials, contribute to biofilm recalcitrance to therapeutic agents. In turn, the ability to kill persister cells is believed to significantly improve efforts in eradicating biofilm-related, chronic infections. While much research has focused on elucidating the mechanism(s) by which persister cells form, little is known about the mechanism or factors that enable persister cells to revert to an active and susceptible state. Here, we demonstrate that cis-2-decenoic acid (cis-DA), a fatty acid signaling molecule, is able to change the status of Pseudomonas aeruginosa and Escherichia coli persister cells from a dormant to a metabolically active state without an increase in cell number. This cell awakening is supported by an increase of the persister cells' respiratory activity together with changes in protein abundance and increases of the transcript expression levels of several metabolic markers, including acpP, 16S rRNA, atpH, and ppx. Given that most antimicrobials target actively growing cells, we also explored the effect of cis-DA on enhancing antibiotic efficacy in killing persister cells due to their inability to keep a persister cell state. Compared to antimicrobial treatment alone, combinational treatments of persister cell subpopulations with antimicrobials and cis-DA resulted in a significantly greater decrease in cell viability. In addition, the presence of cis-DA led to a decrease in the number of persister cells isolated. We thus demonstrate the ability of a fatty acid signaling molecule to revert bacterial cells from a tolerant phenotype to a metabolically active, antimicrobial-sensitive state.
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7
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Kim J, Park W. Oxidative stress response in Pseudomonas putida. Appl Microbiol Biotechnol 2014; 98:6933-46. [PMID: 24957251 DOI: 10.1007/s00253-014-5883-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 06/04/2014] [Accepted: 06/05/2014] [Indexed: 11/30/2022]
Abstract
Pseudomonas putida is widely distributed in nature and is capable of degrading various organic compounds due to its high metabolic versatility. The survival capacity of P. putida stems from its frequent exposure to various endogenous and exogenous oxidative stresses. Oxidative stress is an unavoidable consequence of interactions with various reactive oxygen species (ROS)-inducing agents existing in various niches. ROS could facilitate the evolution of bacteria by mutating genomes. Aerobic bacteria maintain defense mechanisms against oxidative stress throughout their evolution. To overcome the detrimental effects of oxidative stress, P. putida has developed defensive cellular systems involving induction of stress-sensing proteins and detoxification enzymes as well as regulation of oxidative stress response networks. Genetic responses to oxidative stress in P. putida differ markedly from those observed in Escherichia coli and Salmonella spp. Two major redox-sensing transcriptional regulators, SoxR and OxyR, are present and functional in the genome of P. putida. However, the novel regulators FinR and HexR control many genes belonging to the E. coli SoxR regulon. Oxidative stress can be generated by exposure to antibiotics, and iron homeostasis in P. putida is crucial for bacterial cell survival during treatment with antibiotics. This review highlights and summarizes current knowledge of oxidative stress in P. putida, as a model soil bacterium, together with recent studies from molecular genetics perspectives.
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Affiliation(s)
- Jisun Kim
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Anam-Dong 5Ga, Seungbuk-Ku, Seoul, 136-713, Republic of Korea
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8
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Oh SA, Kim JS, Park JY, Han SH, Dimkpa C, Anderson AJ, Kim YC. The RpoS Sigma Factor Negatively Regulates Production of IAA and Siderophore in a Biocontrol Rhizobacterium, Pseudomonas chlororaphis O6. THE PLANT PATHOLOGY JOURNAL 2013; 29:323-9. [PMID: 25288959 PMCID: PMC4174801 DOI: 10.5423/ppj.nt.01.2013.0013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 03/03/2013] [Accepted: 03/03/2013] [Indexed: 05/07/2023]
Abstract
The stationary-phase sigma factor, RpoS, influences the expression of factors important in survival of Pseudomonas chlororaphis O6 in the rhizosphere. A partial proteomic profile of a rpoS mutant in P. chlororaphis O6 was conducted to identify proteins under RpoS regulation. Five of 14 differentially regulated proteins had unknown roles. Changes in levels of proteins in P. chlororaphis O6 rpoS mutant were associated with iron metabolism, and protection against oxidative stress. The P. chlororaphis O6 rpoS mutant showed increased production of a pyoverdine-like siderophore, indole acetic acid, and altered isozyme patterns for peroxidase, catalase and superoxide dismutase. Consequently, sensitivity to hydrogen peroxide exposure increased in the P. chlororaphis O6 rpoS mutant, compared with the wild type. Taken together, RpoS exerted regulatory control over factors important for the habitat of P. chlororaphis O6 in soil and on root surfaces. The properties of several of the proteins in the RpoS regulon are currently unknown.
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Affiliation(s)
- Sang A Oh
- Institute of Environmentally-Friendly Agriculture, Chonnam National University, Gwangju 500-757, Korea
| | - Ji Soo Kim
- Institute of Environmentally-Friendly Agriculture, Chonnam National University, Gwangju 500-757, Korea
| | - Ju Yeon Park
- Institute of Environmentally-Friendly Agriculture, Chonnam National University, Gwangju 500-757, Korea
| | - Song Hee Han
- Institute of Environmentally-Friendly Agriculture, Chonnam National University, Gwangju 500-757, Korea
| | | | | | - Young Cheol Kim
- Institute of Environmentally-Friendly Agriculture, Chonnam National University, Gwangju 500-757, Korea
- Corresponding author. Phone) +82-62-530-2071, FAX) +82-62-530-0208, E-mail)
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9
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The phosphodiesterase DipA (PA5017) is essential for Pseudomonas aeruginosa biofilm dispersion. J Bacteriol 2012; 194:2904-15. [PMID: 22493016 DOI: 10.1128/jb.05346-11] [Citation(s) in RCA: 133] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although little is known regarding the mechanism of biofilm dispersion, it is becoming clear that this process coincides with alteration of cyclic di-GMP (c-di-GMP) levels. Here, we demonstrate that dispersion by Pseudomonas aeruginosa in response to sudden changes in nutrient concentrations resulted in increased phosphodiesterase activity and reduction of c-di-GMP levels compared to biofilm and planktonic cells. By screening mutants inactivated in genes encoding EAL domains for nutrient-induced dispersion, we identified in addition to the previously reported ΔrbdA mutant a second mutant, the ΔdipA strain (PA5017 [dispersion-induced phosphodiesterase A]), to be dispersion deficient in response to glutamate, nitric oxide, ammonium chloride, and mercury chloride. Using biochemical and in vivo studies, we show that DipA associates with the membrane and exhibits phosphodiesterase activity but no detectable diguanylate cyclase activity. Consistent with these data, a ΔdipA mutant exhibited reduced swarming motility, increased initial attachment, and polysaccharide production but only somewhat increased biofilm formation and c-di-GMP levels. DipA harbors an N-terminal GAF (cGMP-specific phosphodiesterases, adenylyl cyclases, and FhlA) domain and two EAL motifs within or near the C-terminal EAL domain. Mutational analyses of the two EAL motifs of DipA suggest that both are important for the observed phosphodiesterase activity and dispersion, while the GAF domain modulated DipA function both in vivo and in vitro without being required for phosphodiesterase activity. Dispersion was found to require protein synthesis and resulted in increased dipA expression and reduction of c-di-GMP levels. We propose a role of DipA in enabling dispersion in P. aeruginosa biofilms.
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10
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Dimkpa CO, McLean JE, Britt DW, Johnson WP, Arey B, Lea AS, Anderson AJ. Nanospecific Inhibition of Pyoverdine Siderophore Production in Pseudomonas chlororaphis O6 by CuO Nanoparticles. Chem Res Toxicol 2012; 25:1066-74. [DOI: 10.1021/tx3000285] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christian O. Dimkpa
- Department of Biological Engineering, Utah State University, Logan Utah 84322, United States
- Department of Biology,
Utah
State University, Logan Utah 84322, United States
| | - Joan E. McLean
- Utah Water Research Laboratory, Utah State University, Logan, Utah 84322, United States
| | - David W. Britt
- Department of Biological Engineering, Utah State University, Logan Utah 84322, United States
| | - William P. Johnson
- Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112, United
States
| | - Bruce Arey
- Pacific Northwest National Laboratory, Richland, Washington 99352, United
States
| | - A. Scott Lea
- Pacific Northwest National Laboratory, Richland, Washington 99352, United
States
| | - Anne J. Anderson
- Department of Biological Engineering, Utah State University, Logan Utah 84322, United States
- Department of Biology,
Utah
State University, Logan Utah 84322, United States
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11
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Fedosov DV, Podkopaeva DA, Miroshnichenko ML, Bonch-Osmolovskaya EA, Lebedinsky AV, Grabovich MY. Investigation of the catabolism of acetate and peptides in the new anaerobic thermophilic bacterium Caldithrix abyssi. Microbiology (Reading) 2006. [DOI: 10.1134/s0026261706020020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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Miller CD, Hall K, Liang YN, Nieman K, Sorensen D, Issa B, Anderson AJ, Sims RC. Isolation and characterization of polycyclic aromatic hydrocarbon-degrading Mycobacterium isolates from soil. MICROBIAL ECOLOGY 2004; 48:230-8. [PMID: 15107954 DOI: 10.1007/s00248-003-1044-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2003] [Accepted: 08/07/2003] [Indexed: 05/19/2023]
Abstract
Bioremediation of soils contaminated with wood preservatives containing polycyclic aromatic hydrocarbons (PAHs) is desired because of their toxic, mutagenic, and carcinogenic properties. Creosote wood preservative-contaminated soils at the Champion International Superfund Site in Libby, Montana currently undergo bioremediation in a prepared-bed land treatment unit (LTU) process. Microbes isolated from these LTU soils rapidly mineralized the (14)C-labeled PAH pyrene in the LTU soil. Gram staining, electron microscopy, and 16S rDNA-sequencing revealed that three of these bacteria, JLS, KMS, and MCS, were Mycobacterium strains. The phylogeny of the 16S rDNA showed that they were distinct from other Mycobacterium isolates with PAH-degrading activities. Catalase and superoxide dismutase (SOD) isozyme profiles confirmed that each isolate was distinct from each other and from the PAH-degrading mycobacterium, Mycobacterium vanbaalenii sp. nov, isolated from a petroleum-contaminated soil. We find that dioxygenase genes nidA and nidB are present in each of the Libby Mycobacterium isolates and are adjacent to each other in the sequence nidB-nidA, an order that is unique to the PAH-degrading mycobacteria.
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Affiliation(s)
- C D Miller
- Department of Biology, Utah State University, Logan, UT 84322, USA.
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13
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Ito SI, Eto T, Tanaka S, Yamauchi N, Takahara H, Ikeda T. Tomatidine and lycotetraose, hydrolysis products of α-tomatine byFusarium oxysporumtomatinase, suppress induced defense responses in tomato cells. FEBS Lett 2004; 571:31-4. [PMID: 15280013 DOI: 10.1016/j.febslet.2004.06.053] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 06/21/2004] [Accepted: 06/21/2004] [Indexed: 11/29/2022]
Abstract
Many fungal pathogens of tomato produce extracellular enzymes, collectively known as tomatinases, that detoxify the preformed antifungal steroidal glycoalkaloid alpha-tomatine. Tomatinase from the vascular wilt pathogen of tomato Fusarium oxysporum f. sp. lycopersici cleaves alpha-tomatine into the aglycon tomatidine (Td) and the tetrasaccharide lycotetraose (Lt). Although modes of action of alpha-tomatine have been extensively studied, those of Td and Lt are poorly understood. Here, we show that both Td and Lt inhibit the oxidative burst and hypersensitive cell death in suspension-cultured tomato cells. A tomatinase-negative F. oxysporum strain inherently non-pathogenic on tomato was able to infect tomato cuttings when either Td or Lt was present. These results suggest that tomatinase from F. oxysporum is required not only for detoxification of alpha-tomatine but also for suppression of induced defense responses of host.
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Affiliation(s)
- Shin-ichi Ito
- Department of Biological and Environmental Sciences, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Yamaguchi 753-8515, Japan.
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14
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Miller CD, Rangel D, Braga GUL, Flint S, Kwon SI, Messias CL, Roberts DW, Anderson AJ. Enzyme activities associated with oxidative stress in Metarhizium anisopliae during germination, mycelial growth, and conidiation and in response to near-UV irradiation. Can J Microbiol 2004; 50:41-9. [PMID: 15052320 DOI: 10.1139/w03-097] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Metarhizium anisopliae isolates have a wide insect host range, but an impediment to their commercial use as a biocontrol agent of above-ground insects is the high susceptibility of spores to the near-UV present in solar irradiation. To understand stress responses in M. anisopliae, we initiated studies of enzymes that protect against oxidative stress in two strains selected because their spores differed in sensitivity to UV-B. Spores of the more near-UV resistant strain in M. anisopliae 324 displayed different isozyme profiles for catalase-peroxidase, glutathione reductase, and superoxide dismutase when compared with the less resistant strain 2575. A transient loss in activity of catalase-peroxidase and glutathione reductase was observed during germination of the spores, whereas the intensity of isozymes displaying superoxide dismutase did not change as the mycelium developed. Isozyme composition for catalase-peroxidases and glutathione reductase in germlings changed with growth phase. UV-B exposure from lamps reduced the activity of isozymes displaying catalase-peroxidase and glutathione reductase activities in 2575 more than in 324. The major effect of solar UV-A plus UV-B also was a reduction in catalase-peroxidases isozyme level, a finding confirmed by measurement of catalase specific activity. Impaired growth of M. anisopliae after near-UV exposure may be related to reduced abilities to handle oxidative stress.
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Affiliation(s)
- Charles D Miller
- Department of Bioloogy, Utah State University, Logan 84322-5305, USA
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15
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Miller CD, Kim YC, Anderson AJ. Competitiveness in root colonization by Pseudomonas putida requires the rpoS gene. Can J Microbiol 2004; 47:41-8. [PMID: 15049448 DOI: 10.1139/w00-123] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The rpoS gene in Pseudomonas putida was essential for plant root colonization under competitive conditions from other microbes. The RpoS- mutant survived less well than the wild-type strain in culture medium, and unlike the wild-type, failed to colonize the roots in a peat matrix containing an established diverse microflora. The RpoS-deficient P. putida isolate was generated by insertion of a glucuronidase-npt cassette into the rpoS gene. The RpoS mutant had dose-dependent increased sensitivity to oxidative stress and produced Mn-superoxide dismutase activity earlier than the parent. While extracts from wild-type P. putida stationary-phase cells contained three isozymes of catalase (CatA, CatB, and CatC), the sigma38-deficient P. putida lacked CatB. These results are consistent with previous findings that CatB is induced in stationary-phase.
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Affiliation(s)
- C D Miller
- Department of Biology, Utah State University, Logan, UT 84522-5305, USA
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16
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Kang BR, Cho BH, Anderson AJ, Kim YC. The global regulator GacS of a biocontrol bacterium Pseudomonas chlororaphis O6 regulates transcription from the rpoS gene encoding a stationary-phase sigma factor and affects survival in oxidative stress. Gene 2004; 325:137-43. [PMID: 14697518 DOI: 10.1016/j.gene.2003.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The global regulator, GacS (global activator for antibiotics and cyanide sensor kinase), of the rhizosphere bacterium Pseudomonas chlororaphis O6 (Pc O6) was required for increased resistance to hydrogen peroxide as cultures mature. Specific bands of peroxidase and catalase activity were absent in the stationary-phase cells of the Pc O6 gacS mutant, whereas a manganese superoxide dismutase (MnSOD) isozyme was expressed earlier and to a greater extent than in the wild-type. In the wild-type cell, transcript accumulation of rpoS was higher in late logarithmic (log)-phase cells than cells from mid log-phase or stationary-phase. Transcript abundance from rpoS was reduced in the gacS mutant throughout the growth phase compared to the wild-type expression. The sequence of a small RNA, rsmZ, found downstream of rpoS in other pseudomonads was lacking in Pc O6. This RNA is implicated in the control of genes activated by the GacS system. Thus, the mechanism by which GacS mediates the activation of genes under its control requires further investigation in Pc O6.
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Affiliation(s)
- Beom Ryong Kang
- Agricultural Plant Stress Research Center and Institute of Agriculture Science, and Technology, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, South Korea
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17
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Anderson AJ, Miller CD. Catalase activity and the survival of Pseudomonas putida, a root colonizer, upon treatment with peracetic acid. Can J Microbiol 2001; 47:222-8. [PMID: 11315113 DOI: 10.1139/w01-002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peracetic acid is used as a sterilant in several industrial settings. Cells of a plant-colonizing bacterium, Pseudomonas putida in liquid suspension, were more sensitive to killing by peracetic acid when they lacked a major catalase activity, catalase A. Low doses of peracetic acid induced promoter activity of the gene encoding catalase A and increased total catalase specific activity in cell extracts. Microbes present in native agricultural soils rapidly degraded the active oxygen species present in peracetic acid. The simultaneous release of oxygen was consistent with a role for catalase in degrading the hydrogen peroxide that is part of the peracetic acid-equilibrium mixture. Amendment of sterilized soils with wild-type P. putida restored the rate of degradation of peracetic acid to a higher level than was observed in the soils amended with the catalase A-deficient mutant. The association of the bacteria with the plant roots resulted in protection of the wild-type as well as the catalase-deficient mutant from killing by peracetic acid. No differential recovery of the wild-type and catalase A mutant of P. putida was observed from roots after the growth matrix containing the plants was flushed with peracetic acid.
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Affiliation(s)
- A J Anderson
- Department of Biology, Utah State University, Logan 84322-5305, USA.
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18
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Miller CD, Kim YC, Walsh MK, Anderson AJ. Characterization and expression of the pseudomonas putida bacterioferritin alpha subunit gene. Gene 2000; 247:199-207. [PMID: 10773460 DOI: 10.1016/s0378-1119(00)00095-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The root-colonizing pseudomonad Pseudomonas putida (Pp) appears to produce two subunits, alpha and beta, of the iron-binding protein, bacterioferritin. A gene encoding the alpha-bacterioferritin subunit was located adjacent to the major catalase in Pp. The deduced protein sequence of the Pp bfralpha gene had a very high identity with other alpha-subunits, possessing conserved amino acids responsible for ferroxidase activity. The gene also lacked a deduced methionine at residue 52, associated with heme binding in beta-subunits. An antibody generated toward the Escherichia coli (E. coli) multifunctional single subunit bacterioferritin recognized two proteins in the Pp extract, a 22 kDa protein likely to be a beta-subunit and, to a lesser extent, a 23 kDa band. The 23 kDa band was absent in a Pp mutant in which the bfralpha gene was disrupted. Loss of alpha-bacterioferritin stimulated production of fluorescent siderophore. Growth on media and on root surfaces was not impaired by deletion of the alpha-bacterioferritin. Transcription of bfralpha was independent of the catalase gene and was dependent on iron. The transcript levels from bfralpha decreased in iron deficiency experienced during stationary-phase or upon treatment during growth with an iron chelator.
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Affiliation(s)
- C D Miller
- Department of Biology, Utah State University, Logan, UT 84322-5305, USA
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19
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Kim YC, Miller CD, Anderson AJ. Superoxide dismutase activity in Pseudomonas putida affects utilization of sugars and growth on root surfaces. Appl Environ Microbiol 2000; 66:1460-7. [PMID: 10742227 PMCID: PMC92008 DOI: 10.1128/aem.66.4.1460-1467.2000] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To investigate the role of superoxide dismutases (SOD) in root colonization and oxidative stress, mutants of Pseudomonas putida lacking manganese-superoxide dismutase (MnSOD) (sodA), iron-superoxide dismutase (FeSOD) (sodB), or both were generated. The sodA sodB mutant did not grow on components washed from bean root surfaces or glucose in minimal medium. The sodB and sodA sodB mutants were more sensitive than wild type to oxidative stress generated within the cell by paraquat treatment. In single inoculation of SOD mutants on bean, only the sodA sodB double mutant was impaired in growth on root surfaces. In mixed inoculations with wild type, populations of the sodA mutant were equal to those of the wild type, but levels of the sodB mutant and, to a great extent, the sodA sodB mutant, were reduced. Confocal microscopy of young bean roots inoculated with green fluorescent protein-tagged cells showed that wild type and SOD single mutants colonized well predominantly at the root tip but that the sodA sodB double mutant grew poorly at the tip. Our results indicate that FeSOD in P. putida is more important than MnSOD in aerobic metabolism and oxidative stress. Inhibition of key metabolic enzymes by increased levels of superoxide anion may cause the impaired growth of SOD mutants in vitro and in planta.
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Affiliation(s)
- Y C Kim
- Department of Biology, Utah State University, Logan, Utah 84322-5305, USA
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20
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Mascher F, Hase C, Moënne-Loccoz Y, Défago G. The viable-but-nonculturable state induced by abiotic stress in the biocontrol agent Pseudomonas fluorescens CHA0 does not promote strain persistence in soil. Appl Environ Microbiol 2000; 66:1662-7. [PMID: 10742257 PMCID: PMC92038 DOI: 10.1128/aem.66.4.1662-1667.2000] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of oxygen limitation, low redox potential, and high NaCl stress for 7 days in vitro on the rifampin-resistant biocontrol inoculant Pseudomonas fluorescens CHA0-Rif and its subsequent persistence in natural soil for 54 days were investigated. Throughout the experiment, the strain was monitored using total cell counts (immunofluorescence microscopy), Kogure's direct viable counts, and colony counts (on rifampin-containing plates). Under in vitro conditions, viable-but-nonculturable (VBNC) cells of CHA0-Rif were obtained when the strain was exposed to a combination of low redox potential (230 mV) and oxygen limitation. This mimics a situation observed in the field, where VBNC cells of the strain were found in the water-logged soil layer above the plow pan. Here, VBNC cells were also observed in vitro when CHA0-Rif was subjected to high NaCl levels (i.e., NaCl at 1.5 M but not 0.7 M). In all treatments, cell numbers remained close to the inoculum level for the first 12 days after inoculation of soil, regardless of the cell enumeration method used, but decreased afterwards. At the last two samplings in soil, VBNC cells of CHA0-Rif were found in all treatments except the one in which log-phase cells had been used. In the two treatments that generated high numbers of VBNC cells in vitro, VBNC cells did not display enhanced persistence compared with culturable cells once introduced into soil, which suggests that this VBNC state did not represent a physiological strategy to improve survival under adverse conditions.
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Affiliation(s)
- F Mascher
- Phytopathology Group, Institute of Plant Science, Swiss Federal Institute of Technology (ETH), CH-8092 Zürich, Switzerland
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21
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Kim YC, Miller CD, Anderson AJ. Transcriptional regulation by iron of genes encoding iron- and manganese-superoxide dismutases from Pseudomonas putida. Gene 1999; 239:129-35. [PMID: 10571042 DOI: 10.1016/s0378-1119(99)00369-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Genes from Pseudomonas putida (Pp), sodA, encoding manganese-superoxide dismutase (MnSOD) and, sodB, iron-superoxide dismutase (FeSOD) were cloned by hybridization with digoxigenin (dig)-labeled PCR products generated from Pp genomic DNA. The sodB gene had a 594 bp open reading frame (ORF), corresponding to 198 amino acids (aa), and a transcript of 880 bases. The sodA gene contained a 609 bp ORF encoding 203 aa and was transcribed as part of a polycistronic operon, consisting of orfY-fumC-orfX-sodA. Pp sodA or sodB genes both restored aerobic growth, growth on paraquat, and growth on minimal medium to an Escherichia coli (Ec) mutant deficient in SOD activity. Paraquat treatment did not enhance mRNA transcription of the sod genes or increase SOD activity in Pp. The Pp sodB gene was highly expressed throughout logarithmic-(log) growth phase and stationary-phase cells grown in medium supplemented with FeCl3, but was down-regulated in iron-deficient conditions, such as in stationary-phase or generated by 2,2'-dipyridyl (DP) treatment. This is the first evidence that iron regulates expression of the sodB gene at the transcriptional level. In contrast, iron-deficient conditions, or addition of MnCl2 to the growth medium, induced transcripts (2.4 kb and 1.2 kb) from the sodA operon. Our results reveal an intricate role of iron in the transcriptional regulation of both Pp sodA and sodB genes.
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Affiliation(s)
- Y C Kim
- Department of Biology, Utah State University, Logan 84322-5305, USA
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22
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Jennings DB, Ehrenshaft M, Pharr DM, Williamson JD. Roles for mannitol and mannitol dehydrogenase in active oxygen-mediated plant defense. Proc Natl Acad Sci U S A 1998; 95:15129-33. [PMID: 9844027 PMCID: PMC24587 DOI: 10.1073/pnas.95.25.15129] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Reactive oxygen species (ROS) are both signal molecules and direct participants in plant defense against pathogens. Many fungi synthesize mannitol, a potent quencher of ROS, and there is growing evidence that at least some phytopathogenic fungi use mannitol to suppress ROS-mediated plant defenses. Here we show induction of mannitol production and secretion in the phytopathogenic fungus Alternaria alternata in the presence of host-plant extracts. Conversely, we show that the catabolic enzyme mannitol dehydrogenase is induced in a non-mannitol-producing plant in response to both fungal infection and specific inducers of plant defense responses. This provides a mechanism whereby the plant can counteract fungal suppression of ROS-mediated defenses by catabolizing mannitol of fungal origin.
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Affiliation(s)
- D B Jennings
- Department of Horticultural Science, North Carolina State University, Raleigh, NC 27695-7609, USA
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23
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Garre V, Müller U, Tudzynski P. Cloning, characterization, and targeted disruption of cpcat1, coding for an in planta secreted catalase of Claviceps purpurea. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 1998; 11:772-783. [PMID: 9675893 DOI: 10.1094/mpmi.1998.11.8.772] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Claviceps purpurea has been shown to secrete catalases in axenic and parasitic culture. In order to determine the importance of these enzymes in the host-parasite interaction, especially their role in overcoming oxidative stress imposed on the pathogen by the plant's defense system, the catR gene from A. niger was used to isolate a putative catalase gene from a genomic library of C. purpurea, cpcat1 consists of an open reading frame of 2,148 bp that is interrupted by five introns. Its derived gene product shows significant homology to fungal catalases and contains a putative signal peptide of 19 amino acids and three putative N-glycosylation sites, which indicates that CPCAT1 is a secreted catalase. Disruption of the gene by a gene replacement approach resulted in the loss of two catalase isoforms, CATC and CATD, strongly suggesting that they are both encoded by cpcat1. CATD is the major secreted catalase of C. purpurea and is furthermore the only catalase present in the honeydew of infected rye ears. Deletion mutants of cpcat1 were inoculated on rye plants and showed no significant reduction in virulence. Ovarian tissue and honeydew of plants inoculated with the mutants lacked CATD, confirming that this catalase is not essential for colonization of the host tissue by C. purpurea.
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Affiliation(s)
- V Garre
- Institut für Botanik, Westfälische Wilhelms-Universität, Münster, Germany
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24
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Kim YC, Miller CD, Anderson AJ. Identification of adjacent genes encoding the major catalase and a bacterioferritin from the plant-beneficial bacterium Pseudomonas putida. Gene X 1997; 199:219-24. [PMID: 9358059 DOI: 10.1016/s0378-1119(97)00370-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The catA gene, encoding the major CatA from a root-colonizing isolate Pseudomonas putida (Pp), was cloned by complementation into a catalase (Cat)-deficient Escherichia coli (Ec) strain UM2. The ORF for catA consisted of 479 aa with a higher degree of identity with typical Cat from eukaryotes than prokaryotes. Chromosomal homologous exchange with a mutant gene bearing an insertion of a luxAB-npt cassette into the SfiI site of catA generated a CatA-deficient Pp isolate. This mutant and another mutant, J1M, derived by EMS mutagenesis, were highly sensitive to hydrogen peroxide. CatA activity and resistance to hydrogen peroxide were restored in both mutants by catA. Adjacent to the 3' end of catA was a potential ORF of 462 nt that had high identitity with other bfr genes that encode iron-storage proteins. Northern analysis of the bfr gene from Pp revealed a transcript of approximately 500 nt. CatA and bfr probes hybridized to the same size restriction fragments in genomic DNAs from other root-colonizing and plant pathogenic pseudomonads. Thus, the genes for an iron-storage protein and the heme-containing Cat appear to be conserved in adjacent loci in certain pseudomonads.
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Affiliation(s)
- Y C Kim
- Department of Biology, Utah State University, Logan 84322-5305, USA
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25
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Miller CD, Kim YC, Anderson AJ. Cloning and mutational analysis of the gene for the stationary-phase inducible catalase (catC) from Pseudomonas putida. J Bacteriol 1997; 179:5241-5. [PMID: 9260972 PMCID: PMC179388 DOI: 10.1128/jb.179.16.5241-5245.1997] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Pseudomonas putida, a bacterium that colonizes plant roots and enhances plant growth, produces three isozymes of catalase (A, B, and C) in stationary-phase cells. A catalase probe, generated by PCR analysis of P. putida genomic DNA with oligomers based on typical catalase sequences, hybridized to a genomic clone that expressed catalase C in Escherichia coli. The catC gene from this clone had a 2,133-bp open reading frame with a high level of identity to the stationary-phase-specific E. coli katE. Chromosomal mutants of P. putida deficient in catalase C, obtained by gene interruption with a luxAB-npt cassette, demonstrated enhanced catC transcription in stationary-phase cells and, upon exposure to phenol, in logarithmic-phase cells. The catalase C-deficient cells were not impaired in their ability to colonize roots of bean or wheat plants grown under sterile conditions.
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Affiliation(s)
- C D Miller
- Department of Biology, Utah State University, Logan 84322-5305, USA
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26
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Glick BR, Bashan Y. Genetic manipulation of plant growth-promoting bacteria to enhance biocontrol of phytopathogens. Biotechnol Adv 1997; 15:353-78. [PMID: 14538716 DOI: 10.1016/s0734-9750(97)00004-9] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Plant growth-promoting bacteria (PGPB) control the damage to plants from phytopathogens by a number of different mechanisms including: outcompeting the phytopathogen, physical displacement of the phytopathogen, secretion of siderophores to prevent pathogens in the immediate vicinity from proliferating, synthesis of antibiotics, synthesis of a variety of small molecules that can inhibit phytopathogen growth, production of enzymes that inhibit the phytopathogen and stimulation of the systemic resistance of the plant. Biocontrol PGPB may be improved by genetically engineering them to overexpress one or more of these traits so that strains with several different anti-phytopathogen traits which can act synergistically are created. In engineering these strains it is essential to ensure that the normal functioning of the bacterium is not impaired, i.e., that there is no problem with metabolic load.
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Affiliation(s)
- B R Glick
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
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27
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Mongkolsuk S, Loprasert S, Vattanaviboon P, Chanvanichayachai C, Chamnongpol S, Supsamran N. Heterologous growth phase- and temperature-dependent expression and H2O2 toxicity protection of a superoxide-inducible monofunctional catalase gene from Xanthomonas oryzae pv. oryzae. J Bacteriol 1996; 178:3578-84. [PMID: 8655557 PMCID: PMC178129 DOI: 10.1128/jb.178.12.3578-3584.1996] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Catalase is an important protective enzyme against H2O2 toxicity. Here, we report the characterization of a Xanthomonas oryzae pv. oryzae catalase gene (katX). The gene was localized and its nucleotide sequence was determined. The gene codes for a 77-kDa polypeptide. The deduced katX amino acid sequence shares regions of high identity with other monofunctional catalases in a range of organisms from bacteria to eukaryotes. The transcriptional regulation of katX was atypical of bacterial monofunctional kat genes. Northern (RNA) analysis showed that katX transcription was highly induced by treatments with low concentrations of menadione, a superoxide generator, and methyl methanesulfonate, a mutagen. It was only weakly induced by H2O2. Unlike in other bacteria, a high level of catalase in Xanthomonas spp. provided protection from the growth-inhibitory and killing effects of H2O2 but not from those of organic peroxides and superoxide generators. Unexpectedly, heterologous expression of katX in Escherichia coli was both growth phase and temperature dependent. Catalase activity in E. coli kat mutants harboring katX on an expression vector was detectable only when the cells entered the stationary phase of growth and at 28 degrees C. The patterns of transcription regulation, heterologous expression, and physiological function of katX are different from previously studied bacterial kat genes.
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Affiliation(s)
- S Mongkolsuk
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok, Thailand
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28
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Sarniguet A, Kraus J, Henkels MD, Muehlchen AM, Loper JE. The sigma factor sigma s affects antibiotic production and biological control activity of Pseudomonas fluorescens Pf-5. Proc Natl Acad Sci U S A 1995; 92:12255-9. [PMID: 8618880 PMCID: PMC40335 DOI: 10.1073/pnas.92.26.12255] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Pseudomonas fluorescens Pf-5, a rhizosphere-inhabiting bacterium that suppresses several soilborne pathogens of plants, produces the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol. A gene necessary for pyrrolnitrin production by Pf-5 was identified as rpoS, which encodes the stationary-phase sigma factor sigma s. Several pleiotropic effects of an rpoS mutation in Escherichia coli also were observed in an RpoS- mutant of Pf-5. These included sensitivities of stationary-phase cells to stresses imposed by hydrogen peroxide or high salt concentration. A plasmid containing the cloned wild-type rpoS gene restored pyrrolnitrin production and stress tolerance to the RpoS- mutant of Pf-5. The RpoS- mutant overproduced pyoluteorin and 2,4-diacetyl-phloroglucinol, two antibiotics that inhibit growth of the phytopathogenic fungus Pythium ultimum, and was superior to the wild type in suppression of seedling damping-off of cucumber caused by Pythium ultimum. When inoculated onto cucumber seed at high cell densities, the RpoS- mutant did not survive as well as the wild-type strain on surfaces of developing seedlings. Other stationary-phase-specific phenotypes of Pf-5, such as the production of cyanide and extracellular protease(s) were expressed by the RpoS- mutant, suggesting that sigma s is only one of the sigma factors required for the transcription of genes in stationary-phase cells of P. fluorescens. These results indicate that a sigma factor encoded by rpoS influences antibiotic production, biological control activity, and survival of P. fluorescens on plant surfaces.
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Affiliation(s)
- A Sarniguet
- Institut National de la Recherche Agronomique, Centre de Recherches de Rennes, Le Rheu, France
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29
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Baker CJ, Harmon GL, Glazener JA, Orlandi EW. A Noninvasive Technique for Monitoring Peroxidative and H2O2-Scavenging Activities during Interactions between Bacterial Plant Pathogens and Suspension Cells. PLANT PHYSIOLOGY 1995; 108:353-359. [PMID: 12228480 PMCID: PMC157341 DOI: 10.1104/pp.108.1.353] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Stimulation of active oxygen metabolism occurs during the early stages of interactions involving bacteria and plant cell suspensions. Although many cellular processes are known to affect active oxygen metabolism in plants, it is not known which of these factors affect active oxygen levels during plant-bacteria interactions. Extracellular peroxidases have been shown to participate in both the production and utilization of active oxygen species such as H2O2 and superoxide. Catalase and other scavenging mechanisms also affect the overall level of active oxygen. In this study the luminol-dependent chemiluminescent reaction previously used to measure H2O2 levels in suspension cells was modified to allow the assay of both peroxidase and H2O2-scavenging activity. The early stages of the interactions between tobacco (Nicotiana tabacum) and Pseudomonas syringae pv syringae, as well as between soybean (Glycine max) and P. syringae pv glycinea, were investigated. This method of monitoring peroxidase and H2O2-scavenging activity proved to be rapid, sensitive, and nonintrusive, allowing the processing of multiple samples using intact cells or cell-free preparations. The results from the study demonstrate that the scavenging activities can be significant and must be considered when studying active oxygen production in biological interactions.
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Affiliation(s)
- C. J. Baker
- Molecular Plant Pathology Laboratory, United States Department of Agriculture, Agricultural Research Service, Beltsville, Maryland 20705
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30
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Abstract
The ways in which plant growth promoting rhizobacteria facilitate the growth of plants are considered and discussed. Both indirect and direct mechanisms of plant growth promotion are dealt with. The possibility of improving plant growth promoting rhizobacteria by specific genetic manipulation is critically examined.Key words: plant growth promoting rhizobacteria, PGPR, bacterial fertilizer, soil bacteria.
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31
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Chamnongpol S, Mongkolsuk S, Vattanaviboon P, Fuangthong M. Unusual Growth Phase and Oxygen Tension Regulation of Oxidative Stress Protection Enzymes, Catalase and Superoxide Dismutase, in the Phytopathogen Xanthomonas oryzae pv. oryzae. Appl Environ Microbiol 1995; 61:393-6. [PMID: 16534917 PMCID: PMC1388338 DOI: 10.1128/aem.61.1.393-396.1995] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The enzymes catalase and superoxide dismutase play major roles in protecting phytopathogenic bacteria from oxidative stress. In Xanthomonas species, these enzymes are regulated by both growth phase and oxygen tension. The highest enzyme levels were detected within 1 h of growth. Continued growth resulted in a decline of both enzyme activities. High oxygen tension was an inducing signal for both enzyme activities. An 80,000-Da monofunctional catalase and a manganese superoxide dismutase were the major forms of the enzymes detected at different stages of growth. The unusual regulatory patterns are common among several Xanthomonas strains tested and may be advantageous to Xanthomonas species during the initial stage of plant-microorganism interactions.
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32
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Binnerup SJÃ, Sørensen J. Long-term oxidant deficiency in Pseudomonas aeruginosa PAO303 results in cells which are non-culturable under aerobic conditions. FEMS Microbiol Ecol 1993. [DOI: 10.1111/j.1574-6941.1993.tb00053.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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33
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Klotz MG, Hutcheson SW. Multiple periplasmic catalases in phytopathogenic strains of Pseudomonas syringae. Appl Environ Microbiol 1992; 58:2468-73. [PMID: 1514792 PMCID: PMC195805 DOI: 10.1128/aem.58.8.2468-2473.1992] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Phytopathogenic strains of Pseudomonas syringae are exposed to plant-produced, detrimental levels of hydrogen peroxide during invasion and colonization of host plant tissue. When P. syringae strains were investigated for their capacity to resist H2O2, they were found to contain 10- to 100-fold-higher levels of total catalase activity than selected strains belonging to nonpathogenic related taxa (Pseudomonas fluorescens and Pseudomonas putida) or Escherichia coli. Multiple catalase activities were identified in both periplasmic and cytoplasmic fluids of exponential- and stationary-phase P. syringae cells. Two of these activities were unique to the periplasm of P. syringae pv. glycinea. During the stationary growth phase, the specific activity of cytoplasmic catalases increased four- to eightfold. The specific activities of catalases in both fluids from exponential-phase cells increased in response to treatment with 0.25 to 10 mM H2O2 but decreased when higher H2O2 concentrations were used. In stationary-growth phase cultures, the specific activities of cytoplasmic catalases increased remarkably after treatment with 0.25 to 50 mM H2O2. The growth of P. syringae into stationary phase and H2O2 treatment did not induce synthesis of additional catalase isozymes. Only the stationary-phase cultures of all of the P. syringae strains which we tested were capable of surviving high H2O2 stress at concentrations up to 50 mM. Our results are consistent with the involvement of multiple catalase isozymes in the reduction of oxidative stress during plant pathogenesis by these bacteria.
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Affiliation(s)
- M G Klotz
- Department of Botany, University of Maryland, College Park 20742
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