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Young D, Pedre B, Ezeriņa D, De Smet B, Lewandowska A, Tossounian MA, Bodra N, Huang J, Astolfi Rosado L, Van Breusegem F, Messens J. Protein Promiscuity in H 2O 2 Signaling. Antioxid Redox Signal 2019; 30:1285-1324. [PMID: 29635930 DOI: 10.1089/ars.2017.7013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SIGNIFICANCE Decrypting the cellular response to oxidative stress relies on a comprehensive understanding of the redox signaling pathways stimulated under oxidizing conditions. Redox signaling events can be divided into upstream sensing of oxidants, midstream redox signaling of protein function, and downstream transcriptional redox regulation. Recent Advances: A more and more accepted theory of hydrogen peroxide (H2O2) signaling is that of a thiol peroxidase redox relay, whereby protein thiols with low reactivity toward H2O2 are instead oxidized through an oxidative relay with thiol peroxidases. CRITICAL ISSUES These ultrareactive thiol peroxidases are the upstream redox sensors, which form the first cellular port of call for H2O2. Not all redox-regulated interactions between thiol peroxidases and cellular proteins involve a transfer of oxidative equivalents, and the nature of redox signaling is further complicated through promiscuous functions of redox-regulated "moonlighting" proteins, of which the precise cellular role under oxidative stress can frequently be obscured by "polygamous" interactions. An ultimate goal of redox signaling is to initiate a rapid response, and in contrast to prokaryotic oxidant-responsive transcription factors, mammalian systems have developed redox signaling pathways, which intersect both with kinase-dependent activation of transcription factors, as well as direct oxidative regulation of transcription factors through peroxiredoxin (Prx) redox relays. FUTURE DIRECTIONS We highlight that both transcriptional regulation and cell fate can be modulated either through oxidative regulation of kinase pathways, or through distinct redox-dependent associations involving either Prxs or redox-responsive moonlighting proteins with functional promiscuity. These protein associations form systems of crossregulatory networks with multiple nodes of potential oxidative regulation for H2O2-mediated signaling.
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Affiliation(s)
- David Young
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Brandan Pedre
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Daria Ezeriņa
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Barbara De Smet
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Aleksandra Lewandowska
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Maria-Armineh Tossounian
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Nandita Bodra
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Jingjing Huang
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Leonardo Astolfi Rosado
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Frank Van Breusegem
- 2 Brussels Center for Redox Biology, Brussels, Belgium.,4 Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium.,5 Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Joris Messens
- 1 Center for Structural Biology, VIB, Brussels, Belgium.,2 Brussels Center for Redox Biology, Brussels, Belgium.,3 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
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102
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OxyR and the hydrogen peroxide stress response in Caulobacter crescentus. Gene 2019; 700:70-84. [PMID: 30880241 DOI: 10.1016/j.gene.2019.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 11/22/2022]
Abstract
Oxidative stress generated by hydrogen peroxide is faced by bacteria when encountering hostile environments. In order to define the physiological and regulatory networks controlling the oxidative stress response in the free-living bacterium Caulobacter crescentus, a whole transcriptome analysis of wild type and ΔoxyR strains in the presence of hydrogen peroxide for two different exposure times was carried out. The C. crescentus response to H2O2 includes a decrease of the assimilative sulfate reduction and a shift in the amino acid synthesis pathways into favoring the synthesis of histidine. Moreover, the expression of genes encoding enzymes for the depolymerization of polyhydroxybutyrate was increased, and the RpoH-dependent genes were severely repressed. Based on the expression pattern and sequence analysis, we postulate that OxyR is probably directly required for the induction of three genes (katG, ahpCF). The putative binding of OxyR to the ahpC regulatory region could be responsible for the use of one of two alternative promoters in response to oxidative stress. Nevertheless, OxyR is required for the expression of 103 genes in response to H2O2. Fur and part of its regulon were differentially expressed in response to hydrogen peroxide independently of OxyR. The non-coding RNA OsrA was upregulated in both strains, and an in silico analysis indicated that it may have a regulatory role. This work characterizes the physiological response to H2O2 in C. crescentus, the regulatory networks and differentially regulated genes in oxidative stress and the participation of OxyR in this process. It is proposed that besides OxyR, a second layer of regulation may be achieved by a small regulatory RNA and other transcriptional regulators.
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103
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The osnR gene of Corynebacterium glutamicum plays a negative regulatory role in oxidative stress responses. ACTA ACUST UNITED AC 2019; 46:241-248. [DOI: 10.1007/s10295-018-02126-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 12/20/2018] [Indexed: 11/26/2022]
Abstract
Abstract
Among the Corynebacterium glutamicum ORFs that have been implicated in stress responses, we chose ORF cg3230, designated osnR, and analyzed it further. Unlike the osnR-deleted strain (ΔosnR), the osnR-overexpressing strain (P180-osnR) developed growth defects and increased sensitivity to various oxidants including H2O2. Transcription in the P180-osnR strain of genes such as sodA (superoxide dismutase), ftn (ferritin biosynthesis), and ahpD (alkyl hydroperoxide reductase; cg2674), which are involved in the detoxification of reactive oxygen species, was only 40% that of the wild type. However, transcription of katA, encoding H2O2-detoxifying catalase, was unchanged in this strain. Genes such as trxB (thioredoxin reductase) and mtr (mycothiol disulfide reductase), which play roles in redox homeostasis, also showed decreased transcription in the strain. 2D-PAGE analysis indicated that genes involved in redox reactions were considerably affected by osnR overexpression. The NADPH/NADP+ ratio of the P180-osnR strain (1.35) was higher than that of the wild-type stain (0.78). Collectively, the phenotypes of the ΔosnR and P180-osnR strains suggest a global regulatory role as well as a negative role for the gene in stress responses, particularly in katA-independent oxidative stress responses.
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104
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Lim S, Jung JH, Blanchard L, de Groot A. Conservation and diversity of radiation and oxidative stress resistance mechanisms in Deinococcus species. FEMS Microbiol Rev 2019; 43:19-52. [PMID: 30339218 PMCID: PMC6300522 DOI: 10.1093/femsre/fuy037] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 10/17/2018] [Indexed: 12/17/2022] Open
Abstract
Deinococcus bacteria are famous for their extreme resistance to ionising radiation and other DNA damage- and oxidative stress-generating agents. More than a hundred genes have been reported to contribute to resistance to radiation, desiccation and/or oxidative stress in Deinococcus radiodurans. These encode proteins involved in DNA repair, oxidative stress defence, regulation and proteins of yet unknown function or with an extracytoplasmic location. Here, we analysed the conservation of radiation resistance-associated proteins in other radiation-resistant Deinococcus species. Strikingly, homologues of dozens of these proteins are absent in one or more Deinococcus species. For example, only a few Deinococcus-specific proteins and radiation resistance-associated regulatory proteins are present in each Deinococcus, notably the metallopeptidase/repressor pair IrrE/DdrO that controls the radiation/desiccation response regulon. Inversely, some Deinococcus species possess proteins that D. radiodurans lacks, including DNA repair proteins consisting of novel domain combinations, translesion polymerases, additional metalloregulators, redox-sensitive regulator SoxR and manganese-containing catalase. Moreover, the comparisons improved the characterisation of several proteins regarding important conserved residues, cellular location and possible protein–protein interactions. This comprehensive analysis indicates not only conservation but also large diversity in the molecular mechanisms involved in radiation resistance even within the Deinococcus genus.
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Affiliation(s)
- Sangyong Lim
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup 56212, Republic of Korea
| | - Jong-Hyun Jung
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup 56212, Republic of Korea
| | | | - Arjan de Groot
- Aix Marseille Univ, CEA, CNRS, BIAM, Saint Paul-Lez-Durance, France
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105
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Gunawardena D, Raju R, Münch G. Hydrogen peroxide mediates pro-inflammatory cell-to-cell signaling: a new therapeutic target for inflammation? Neural Regen Res 2019; 14:1430-1437. [PMID: 30964069 PMCID: PMC6524506 DOI: 10.4103/1673-5374.253529] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Nitric oxide is now universally recognized as an extracellular signaling molecule. Nitric oxide, produced in one cell, diffuses across the extracellular space and acts with targets in an adjoining cell. In this study, we present proof that hydrogen peroxide – like nitric oxide – acts as a true first (intercellular) messenger for a multitude of pro-inflammatory ligands. RAW 264.7 macrophages were activated with three different ligands, lipopolysaccharide, interferon-gamma or advanced glycation end products in the presence of increasing concentrations of (hydrogen peroxide scavenging) catalase. As inflammatory readouts, nitric oxide and tumor necrosis factor were determined. We hypothesize that hydrogen peroxide travels between cells propagating the signal, then a certain percentage of the readout should be inhibited by catalase in a concentration-dependent manner. The experiment showed concentration-dependent inhibition of nitric oxide and tumor necrosis factor-α production in response to all three ligands/ligand combinations (interferon-gamma, lipopolysaccharide, and chicken egg albumin-derived advanced glycation end product) in the presence of increasing concentration of catalase. For example, catalase inhibited 100% of nitric oxide and 40% of tumor necrosis factor-α production at its highest concentration. Our results suggest that hydrogen peroxide travels through cell membranes into the extracellular space and enters and activates adjacent cells. Like nitric oxide, we suggest that it is a ubiquitous first messenger, able to transmit cell-to-cell pro-inflammatory signals such as nitric oxide and tumor necrosis factor-α. In a therapeutic setting, our data suggest that compounds acting as hydrogen peroxide scavengers might not even need to enter the cell to act as anti-inflammatory drugs.
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Affiliation(s)
- Dhanushka Gunawardena
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Ritesh Raju
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
| | - Gerald Münch
- Department of Pharmacology, School of Medicine, Western Sydney University, Penrith, NSW, Australia
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106
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OhsR acts as an organic peroxide-sensing transcriptional activator using an S-mycothiolation mechanism in Corynebacterium glutamicum. Microb Cell Fact 2018; 17:200. [PMID: 30587200 PMCID: PMC6306002 DOI: 10.1186/s12934-018-1048-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/14/2018] [Indexed: 11/21/2022] Open
Abstract
Background Corynebacterium glutamicum is a well-known producer of various l-amino acids in industry. During the fermenting process, C. glutamicum unavoidably encounters oxidative stress due to a specific reactive oxygen species (ROS) produced by consistent adverse conditions. To combat the ROS, C. glutamicum has developed many common disulfide bond-based regulatory devices to control a specific set of antioxidant genes. However, nothing is known about the mixed disulfide between the protein thiol groups and the mycothiol (MSH) (S-mycothiolation)-based sensor. In addition, no OhrR (organic hydroperoxide resistance regulator) homologs and none of the organic hydroperoxide reductase (Ohr) sensors have been described in the alkyl hydroperoxide reductase CF-missing C. glutamicum, while organic hydroperoxides (OHPs)-specific Ohr was a core detoxification system. Results In this study, we showed that the C. glutamicum OhsR acted as an OHPs sensor that activated ohr expression. OhsR conferred resistance to cumene hydroperoxide (CHP) and t-butyl hydroperoxide but not H2O2, hypochlorous acid, and diamide; this outcome was substantiated by the fact that the ohsR-deficient mutant was sensitive to OHPs but not inorganic peroxides. The DNA binding activity of OhsR was specifically activated by CHP. Mutational analysis of the two cysteines (Cys125 and Cys261) showed that Cys125 was primarily responsible for the activation of DNA binding. The oxidation of Cys125 produced a sulfenic acid (C125-SOH) that subsequently reacted with MSH to generate S-mycothiolation that was required to activate the ohr expression. Therefore, OhsR regulated the ohr expression using an S-mycothiolation mechanism in vivo. Conclusion This is the first report demonstrating that the regulatory OhsR specifically sensed OHPs stress and responded to it by activating a specific ohr gene under its control using an S-mycothiolated mechanism. Electronic supplementary material The online version of this article (10.1186/s12934-018-1048-y) contains supplementary material, which is available to authorized users.
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107
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Acinetobacter baumannii OxyR Regulates the Transcriptional Response to Hydrogen Peroxide. Infect Immun 2018; 87:IAI.00413-18. [PMID: 30297527 DOI: 10.1128/iai.00413-18] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/03/2018] [Indexed: 12/21/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic pathogen that causes diverse infections, including pneumonia, bacteremia, and wound infections. Due to multiple intrinsic and acquired antimicrobial-resistance mechanisms, A. baumannii isolates are commonly multidrug resistant, and infections are notoriously difficult to treat. The World Health Organization recently highlighted carbapenem-resistant A. baumannii as a "critical priority" for the development of new antimicrobials because of the risk to human health posed by this organism. Therefore, it is important to discover the mechanisms used by A. baumannii to survive stresses encountered during infection in order to identify new drug targets. In this study, by use of in vivo imaging, we identified hydrogen peroxide (H2O2) as a stressor produced in the lung during A. baumannii infection and defined OxyR as a transcriptional regulator of the H2O2 stress response. Upon exposure to H2O2, A. baumannii differentially transcribes several hundred genes. However, the transcriptional upregulation of genes predicted to detoxify hydrogen peroxide is abolished in an A. baumannii strain in which the transcriptional regulator oxyR is genetically inactivated. Moreover, inactivation of oxyR in both antimicrobial-susceptible and multidrug-resistant A. baumannii strains impairs growth in the presence of H2O2 OxyR is a direct regulator of katE and ahpF1, which encode the major H2O2-degrading enzymes in A. baumannii, as confirmed through measurement of promoter binding by recombinant OxyR in electromobility shift assays. Finally, an oxyR mutant is less fit than wild-type A. baumannii during infection of the murine lung. This work reveals a mechanism used by this important human pathogen to survive H2O2 stress encountered during infection.
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108
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Alloing G, Mandon K, Boncompagni E, Montrichard F, Frendo P. Involvement of Glutaredoxin and Thioredoxin Systems in the Nitrogen-Fixing Symbiosis between Legumes and Rhizobia. Antioxidants (Basel) 2018; 7:E182. [PMID: 30563061 PMCID: PMC6315971 DOI: 10.3390/antiox7120182] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 01/08/2023] Open
Abstract
Leguminous plants can form a symbiotic relationship with Rhizobium bacteria, during which plants provide bacteria with carbohydrates and an environment appropriate to their metabolism, in return for fixed atmospheric nitrogen. The symbiotic interaction leads to the formation of a new organ, the root nodule, where a coordinated differentiation of plant cells and bacteria occurs. The establishment and functioning of nitrogen-fixing symbiosis involves a redox control important for both the plant-bacteria crosstalk and the regulation of nodule metabolism. In this review, we discuss the involvement of thioredoxin and glutaredoxin systems in the two symbiotic partners during symbiosis. The crucial role of glutathione in redox balance and S-metabolism is presented. We also highlight the specific role of some thioredoxin and glutaredoxin systems in bacterial differentiation. Transcriptomics data concerning genes encoding components and targets of thioredoxin and glutaredoxin systems in connection with the developmental step of the nodule are also considered in the model system Medicago truncatula⁻Sinorhizobium meliloti.
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Affiliation(s)
| | | | | | - Françoise Montrichard
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, 49071 Beaucouzé CEDEX, France.
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109
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Pan X, Wu J, Xu S, Duan T, Duan Y, Wang J, Zhang F, Zhou M. Contribution of OxyR Towards Differential Sensitivity to Antioxidants in Xanthomonas oryzae pathovars oryzae and oryzicola. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:1244-1256. [PMID: 29905495 DOI: 10.1094/mpmi-03-18-0074-r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
OxyR and SoxR are two transcriptional regulators in response to oxidative stress in most bacteria, and SoxR has been reported to be activated by the endogenous redox-cycling compound phenazine in phenazine-producing organisms. However, which transcriptional regulator is activated in pathogens treated with the antibiotic phenazine-1-carboxylic acid (PCA) has not been determined. In this study, we found that PCA treatment activated OxyR rather than SoxR in the phytopathogenic bacteria Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola. We also found that X. oryzae pv. oryzae was much more sensitive to PCA and H2O2 and had a defective antioxidant system (i.e., less of total antioxidant capacity and total catalase activity than X. oryzae pv. oryzicola, although X. oryzae pvs. oryzae and oryzicola are very closely related). Based on KEGG sequences, OxyR differs in 10 amino acids in X. oryzae pv. oryzae versus X. oryzae pv. oryzicola. By exchanging OxyR between X. oryzae pvs. oryzae and oryzicola, we elucidated that OxyR contributed to the differences in antioxidant capacity, total catalase activity, and sensitivity to PCA and H2O2. We also found that OxyR affected X. oryzae pvs. oryzae and oryzicola growth in a nutrient-poor medium, virulence on host plants (rice), and the hypersensitive response on nonhost plants (Nicotiana benthamiana). Thus, OxyR is a critical regulator that relates to the differences in antioxidative stress between X. oryzae pvs. oryzae and oryzicola and contributes to the differences in survival of them against oxidative stress.
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Affiliation(s)
- Xiayan Pan
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jian Wu
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Shu Xu
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Tingting Duan
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yabing Duan
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jianxin Wang
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Feng Zhang
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
| | - Mingguo Zhou
- College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing, 210095, China
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Role and Function of Class III LitR, a Photosensor Homolog from Burkholderia multivorans. J Bacteriol 2018; 200:JB.00285-18. [PMID: 30249707 DOI: 10.1128/jb.00285-18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/13/2018] [Indexed: 11/20/2022] Open
Abstract
The LitR/CarH protein family is an adenosyl B12 (AdoB12)-dependent photoreceptor family with DNA-binding activity, and its homologs are widely distributed in the genomes of diverse bacterial genera. In this investigation, we studied the role and functions of a LitR homolog from a Gram-negative soil bacterium, Burkholderia multivorans, which does not possess an AdoB12-binding domain. Transcriptome analysis indicated the existence of 19 light-induced genes, including folE2, cfaB, litS, photolyase gene phrB2, and cryB, located in the region flanking litR Disruption of litR caused constitutive expression of all the light-inducible genes, while mutation in the light-induced sigma factor gene, litS, abolished the transcription of the phrB2 operon and the cfa operon, indicating that LitR and LitS play a central role in light-inducible transcription. A gel shift assay showed that recombinant protein LitR specifically binds to the promoter regions of litR and the folE2 operon, and its binding was weakened by UV-A illumination. LitR absorbs light at maximally near 340 nm and exhibited a photocyclic response and light-dependent dissociation of multimer into tetramer. The litR mutant produced a 20-fold-higher intracellular level of folate than that of the wild-type strain. Thus, the evidence suggests that LitR light-dependently regulates the transcription of litR itself and the folE2 operon, resulting in the production of folate, and then the expressed RNA polymerase complex containing σLitS directs the transcription of the phrB2 operon and the cfa operon. These light-dependent characteristics suggest that class III LitR, in complex with a UV-A-absorbing molecule, follows a novel light-sensing mechanism.IMPORTANCE Members of the LitR/CarH family are adenosyl B12-based photosensory transcriptional regulator involved in light-inducible carotenoid production in nonphototrophic bacteria. Our study provides the first evidence of the involvement of a class III LitR, which lacks an adenosyl B12-binding domain in the light response of Burkholderia multivorans belonging to betaproteobacteria. Our biochemical analysis suggests that class III LitR protein exhibits features as a photosensor including absorption of light at the UV-A region (λmax = ca. 340 nm), photocyclic response, and light-dependent dissociation. This suggests that class III LitR associates with a UV-A-absorbing molecule, and it has a photosensing mechanism distinguishable from that of the B12-based type.
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111
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Coping with Reactive Oxygen Species to Ensure Genome Stability in Escherichia coli. Genes (Basel) 2018; 9:genes9110565. [PMID: 30469410 PMCID: PMC6267047 DOI: 10.3390/genes9110565] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 11/15/2018] [Accepted: 11/16/2018] [Indexed: 12/16/2022] Open
Abstract
The facultative aerobic bacterium Escherichia coli adjusts its cell cycle to environmental conditions. Because of its lifestyle, the bacterium has to balance the use of oxygen with the potential lethal effects of its poisonous derivatives. Oxidative damages perpetrated by molecules such as hydrogen peroxide and superoxide anions directly incapacitate metabolic activities relying on enzymes co-factored with iron and flavins. Consequently, growth is inhibited when the bacterium faces substantial reactive oxygen insults coming from environmental or cellular sources. Although hydrogen peroxide and superoxide anions do not oxidize DNA directly, these molecules feed directly or indirectly the generation of the highly reactive hydroxyl radical that damages the bacterial chromosome. Oxidized bases are normally excised and the single strand gap repaired by the base excision repair pathway (BER). This process is especially problematic in E. coli because replication forks do not sense the presence of damages or a stalled fork ahead of them. As consequence, single-strand breaks are turned into double-strand breaks (DSB) through replication. Since E. coli tolerates the presence of DSBs poorly, BER can become toxic during oxidative stress. Here we review the repair strategies that E. coli adopts to preserve genome integrity during oxidative stress and their relation to cell cycle control of DNA replication.
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112
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Tung QN, Loi VV, Busche T, Nerlich A, Mieth M, Milse J, Kalinowski J, Hocke AC, Antelmann H. Stable integration of the Mrx1-roGFP2 biosensor to monitor dynamic changes of the mycothiol redox potential in Corynebacterium glutamicum. Redox Biol 2018; 20:514-525. [PMID: 30481728 PMCID: PMC6258114 DOI: 10.1016/j.redox.2018.11.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 11/08/2018] [Accepted: 11/15/2018] [Indexed: 12/20/2022] Open
Abstract
Mycothiol (MSH) functions as major low molecular weight (LMW) thiol in the industrially important Corynebacterium glutamicum. In this study, we genomically integrated an Mrx1-roGFP2 biosensor in C. glutamicum to measure dynamic changes of the MSH redox potential (EMSH) during the growth and under oxidative stress. C. glutamicum maintains a highly reducing intrabacterial EMSH throughout the growth curve with basal EMSH levels of ~- 296 mV. Consistent with its H2O2 resistant phenotype, C. glutamicum responds only weakly to 40 mM H2O2, but is rapidly oxidized by low doses of NaOCl. We further monitored basal EMSH changes and the H2O2 response in various mutants which are compromised in redox-signaling of ROS (OxyR, SigH) and in the antioxidant defense (MSH, Mtr, KatA, Mpx, Tpx). While the probe was constitutively oxidized in the mshC and mtr mutants, a smaller oxidative shift in basal EMSH was observed in the sigH mutant. The catalase KatA was confirmed as major H2O2 detoxification enzyme required for fast biosensor re-equilibration upon return to non-stress conditions. In contrast, the peroxiredoxins Mpx and Tpx had only little impact on EMSH and H2O2 detoxification. Further live imaging experiments using confocal laser scanning microscopy revealed the stable biosensor expression and fluorescence at the single cell level. In conclusion, the stably expressed Mrx1-roGFP2 biosensor was successfully applied to monitor dynamic EMSH changes in C. glutamicum during the growth, under oxidative stress and in different mutants revealing the impact of Mtr and SigH for the basal level EMSH and the role of OxyR and KatA for efficient H2O2 detoxification under oxidative stress.
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Affiliation(s)
- Quach Ngoc Tung
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195 Berlin, Germany
| | - Vu Van Loi
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195 Berlin, Germany
| | - Tobias Busche
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195 Berlin, Germany; Center for Biotechnology (CeBiTec), Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Andreas Nerlich
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité -Universitätsmedizin Berlin, D-10117 Berlin, Germany
| | - Maren Mieth
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité -Universitätsmedizin Berlin, D-10117 Berlin, Germany
| | - Johanna Milse
- Center for Biotechnology (CeBiTec), Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Jörn Kalinowski
- Center for Biotechnology (CeBiTec), Universitätsstraße 25, D-33615 Bielefeld, Germany
| | - Andreas C Hocke
- Department of Internal Medicine/Infectious Diseases and Respiratory Medicine, Charité -Universitätsmedizin Berlin, D-10117 Berlin, Germany
| | - Haike Antelmann
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195 Berlin, Germany.
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113
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Hong EJ, Jeong H, Lee DS, Kim Y, Lee HS. TheahpDgene ofCorynebacterium glutamicumplays an important role in hydrogen peroxide-induced oxidative stress response. J Biochem 2018; 165:197-204. [DOI: 10.1093/jb/mvy097] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 11/14/2018] [Indexed: 12/17/2022] Open
Affiliation(s)
- Eun-Ji Hong
- Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong-si, Korea
| | - Haeri Jeong
- Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong-si, Korea
| | - Dong-Seok Lee
- Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong-si, Korea
| | - Younhee Kim
- Department of Korean Medicine, Semyung University, 65 Semyeong-ro, Jecheon-si, Chungbuk, Korea
| | - Heung-Shick Lee
- Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong-si, Korea
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114
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Ruhland BR, Reniere ML. Sense and sensor ability: redox-responsive regulators in Listeria monocytogenes. Curr Opin Microbiol 2018; 47:20-25. [PMID: 30412828 DOI: 10.1016/j.mib.2018.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 12/20/2022]
Abstract
Listeria monocytogenes (Lm) is a Gram-positive bacterium that thrives in nature as a saprophyte and in the mammalian host as an intracellular pathogen. Both environments pose potential danger in the form of redox stress. In addition, endogenous reactive oxygen species (ROS) are continuously generated as by-products of aerobic metabolism. Redox stress from ROS can damage proteins, lipids, and DNA, making it highly advantageous for bacteria to evolve mechanisms to sense and detoxify ROS. This review focuses on the five redox-responsive regulators in Lm: OhrR (to sense organic hydroperoxides), PerR (peroxides), Rex (NAD+/NADH homeostasis), SpxA1/2 (disulfide stress), and PrfA (redox stress during infection).
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115
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Mendis N, Trigui H, Saad M, Tsang A, Faucher SP. Deletion of oxyR in Legionella pneumophila causes growth defect on agar. Can J Microbiol 2018; 64:1030-1041. [PMID: 30212639 DOI: 10.1139/cjm-2018-0129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The intracellular pathogen Legionella pneumophila (Lp) is a strict aerobe, surviving and replicating in environments where it frequently encounters reactive oxygen species (ROS), such as the nutrient-poor water environment and its replicative niche inside host cells. In many proteobacteria, the LysR-type regulator OxyR controls the oxidative stress response; however, the importance of the OxyR homologue in Lp is still unclear. Therefore, we undertook the characterization of phenotypes associated with the deletion of oxyR in Lp. Contrary to the wild type, the oxyR deletion mutant exhibits a severe growth defect on charcoal - yeast extract (CYE) agar lacking α-ketoglutarate supplementation. Growth in AYE broth (CYE without agar and charcoal), in amoeba and in human cultured macrophages, and survival in water is unaffected by the deletion. Supplementing CYE agar with antioxidants that neutralize ROS or introducing the oxyR gene in trans rescues the observed growth defect. Moreover, the mutant grows as well as the wild type on CYE plates made with agarose instead of agar, suggesting that a compound present in the latter is responsible for the growth defect phenotype.
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Affiliation(s)
- Nilmini Mendis
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Hana Trigui
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Mariam Saad
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Adrianna Tsang
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
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116
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Abstract
SIGNIFICANCE Hydrogen peroxide (H2O2) is a key signaling molecule involved in the regulation of both physiological and pathological cellular processes. Genetically encoded HyPer probes are currently among the most effective approaches for monitoring H2O2 dynamics in various biological systems because they can be easily targeted to specific cells and organelles. Since its development in 2006, HyPer has proved to be a robust and powerful tool in redox biology research. Recent Advances: HyPer probes were used in a variety of models to study the role of H2O2 in various redox processes. HyPer has been increasingly used in the past few years for in vivo studies, which has already led to many important discoveries, for example, that H2O2 plays a key role in the regulation of signaling cascades involved in development and aging, inflammation, regeneration, photosynthetic signaling, and other biological processes. CRITICAL ISSUES In this review, we focus on the main achievements in the field of redox biology that have been obtained from in vivo experiments using HyPer probes. FUTURE DIRECTIONS Further in vivo studies of the role of H2O2 largely depend on the development of more suitable versions of HyPer for in vivo models: those having brighter fluorescence and a more stable signal in response to physiological changes in pH. Antioxid. Redox Signal. 29, 569-584.
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Affiliation(s)
- Dmitry S Bilan
- 1 Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia .,2 Pirogov Russian National Research Medical University , Moscow, Russia
| | - Vsevolod V Belousov
- 1 Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia .,2 Pirogov Russian National Research Medical University , Moscow, Russia .,3 Institute for Cardiovascular Physiology, Georg August University Göttingen , Göttingen, Germany
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117
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Romsang A, Duang-Nkern J, Khemsom K, Wongsaroj L, Saninjuk K, Fuangthong M, Vattanaviboon P, Mongkolsuk S. Pseudomonas aeruginosa ttcA encoding tRNA-thiolating protein requires an iron-sulfur cluster to participate in hydrogen peroxide-mediated stress protection and pathogenicity. Sci Rep 2018; 8:11882. [PMID: 30089777 PMCID: PMC6082896 DOI: 10.1038/s41598-018-30368-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/27/2018] [Indexed: 01/21/2023] Open
Abstract
During the translation process, transfer RNA (tRNA) carries amino acids to ribosomes for protein synthesis. Each codon of mRNA is recognized by a specific tRNA, and enzyme-catalysed modifications to tRNA regulate translation. TtcA is a unique tRNA-thiolating enzyme that requires an iron-sulfur ([Fe-S]) cluster to catalyse thiolation of tRNA. In this study, the physiological functions of a putative ttcA in Pseudomonas aeruginosa, an opportunistic human pathogen that causes serious problems in hospitals, were characterized. A P. aeruginosa ttcA-deleted mutant was constructed, and mutant cells were rendered hypersensitive to oxidative stress, such as hydrogen peroxide (H2O2) treatment. Catalase activity was lower in the ttcA mutant, suggesting that this gene plays a role in protecting against oxidative stress. Moreover, the ttcA mutant demonstrated attenuated virulence in a Drosophila melanogaster host model. Site-directed mutagenesis analysis revealed that the conserved cysteine motifs involved in [Fe-S] cluster ligation were required for TtcA function. Furthermore, ttcA expression increased upon H2O2 exposure, implying that enzyme levels are induced under stress conditions. Overall, the data suggest that P. aeruginosa ttcA plays a critical role in protecting against oxidative stress via catalase activity and is required for successful bacterial infection of the host.
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Affiliation(s)
- Adisak Romsang
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand. .,Center for Emerging Bacterial Infections, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
| | - Jintana Duang-Nkern
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Khwannarin Khemsom
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Lampet Wongsaroj
- Molecular Medicine Graduate Program, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Kritsakorn Saninjuk
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
| | - Mayuree Fuangthong
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Paiboon Vattanaviboon
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, 10210, Thailand
| | - Skorn Mongkolsuk
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Center for Emerging Bacterial Infections, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.,Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, 10210, Thailand.,Molecular Medicine Graduate Program, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand
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118
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Oladeinde A, Lipp E, Chen CY, Muirhead R, Glenn T, Cook K, Molina M. Transcriptome Changes of Escherichia coli, Enterococcus faecalis, and Escherichia coli O157:H7 Laboratory Strains in Response to Photo-Degraded DOM. Front Microbiol 2018; 9:882. [PMID: 29867797 PMCID: PMC5953345 DOI: 10.3389/fmicb.2018.00882] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/17/2018] [Indexed: 11/26/2022] Open
Abstract
In this study, we investigated gene expression changes in three bacterial strains (Escherichia coli C3000, Escherichia coli O157:H7 B6914, and Enterococcus faecalis ATCC 29212), commonly used as indicators of water quality and as control strains in clinical, food, and water microbiology laboratories. Bacterial transcriptome responses from pure cultures were monitored in microcosms containing water amended with manure-derived dissolved organic matter (DOM), previously exposed to simulated sunlight for 12 h. We used RNA sequencing (RNA-seq) and quantitative real-time reverse transcriptase (qRT-PCR) to compare differentially expressed temporal transcripts between bacteria incubated in microcosms containing sunlight irradiated and non-irradiated DOM, for up to 24 h. In addition, we used whole genome sequencing simultaneously with RNA-seq to identify single nucleotide variants (SNV) acquired in bacterial populations during incubation. These results indicate that E. coli and E. faecalis have different mechanisms for removal of reactive oxygen species (ROS) produced from irradiated DOM. They are also able to produce micromolar concentrations of H2O2 from non-irradiated DOM, that should be detrimental to other bacteria present in the environment. Notably, this study provides an assessment of the role of two conjugative plasmids carried by the E. faecalis and highlights the differences in the overall survival dynamics of environmentally-relevant bacteria in the presence of naturally-produced ROS.
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Affiliation(s)
- Adelumola Oladeinde
- National Exposure Research Laboratory, Student Volunteer, U.S. Environmental Protection Agency, Office of Research and Development, Athens, GA, United States.,Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Erin Lipp
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Chia-Ying Chen
- National Exposure Research Laboratory, National Research Council Associate, U.S. Environmental Protection Agency, Office of Research and Development, Athens, GA, United States
| | | | - Travis Glenn
- Department of Environmental Health Science, University of Georgia, Athens, GA, United States
| | - Kimberly Cook
- Bacterial Epidemiology and Antimicrobial Resistance Research Unit, U.S. National Poultry Research Center, Agricultural Research Service, United States Department of Agriculture, Athens, GA, United States
| | - Marirosa Molina
- National Exposure Research Laboratory, U.S. Environmental Protection Agency, Office of Research and Development, Athens, GA, United States
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119
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Li X, Imlay JA. Improved measurements of scant hydrogen peroxide enable experiments that define its threshold of toxicity for Escherichia coli. Free Radic Biol Med 2018; 120:217-227. [PMID: 29550333 PMCID: PMC5940505 DOI: 10.1016/j.freeradbiomed.2018.03.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/06/2023]
Abstract
Escherichia coli is a model organism that has been exploited to reveal key details of hydrogen peroxide stress: the biomolecules that H2O2 most rapidly damages and the defensive tactics that organisms use to fend it off. Much less clear is the amount of exogenous H2O2 that is sufficient to injure the bacterium and/or to trigger its stress response. To fill this gap, we need to study the behavior of cells when they are exposed to defined amounts of H2O2 on an hours-long time scale. Such experiments are difficult because bacteria rapidly consume H2O2 that is added to test cultures. Further, lab media itself can generate H2O2, and media components interfere with the quantification of H2O2 levels. In this study we describe mechanisms by which media components interfere with H2O2 determinations, and we identify simple ways to minimize and correct for this interference. Using these techniques, it was shown that standard media generate so much H2O2 that most intracellular H2O2 derives from the medium rather than from endogenous metabolism. Indeed, bacteria spread on plates must induce their stress response or else perish. Finally, two straightforward methods were used to sustain low-micromolar steady-state concentrations of H2O2. In this way we determined that > 2 μM extracellular H2O2 is sufficient to trigger the intracellular OxyR stress response, and > 5 μM begins to impair cell growth in a minimal medium. These concentrations are orders of magnitude lower than the doses that have typically been used in lab experiments. The new approaches should enable workers to study how various organisms cope with natural levels of H2O2 stress.
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Affiliation(s)
- Xin Li
- College of Food and Bioengineering, Henan University of Science and Technology, No. 263, Kaiyuan Ave., Luoyang, Henan 471023, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
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120
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Eltarahony M, Zaki S, Kheiralla Z, Abd-El-Haleem D. NAP enzyme recruitment in simultaneous bioremediation and nanoparticles synthesis. ACTA ACUST UNITED AC 2018; 18:e00257. [PMID: 29876306 PMCID: PMC5989592 DOI: 10.1016/j.btre.2018.e00257] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 11/30/2022]
Abstract
This study employed the immobilized strain MMT and its NAP enzyme in concurrent denitrification and NPs synthesis. The properties of crude NAP enzyme were assessed at different ranges of pH and temperatures and also its stability at 4 °C and 30 °C was studied. The effect of several types of additives were evaluated at concentration rang (1 mM, 2.5 mM, 5 mM and 10 mM). Concurrently, the immobilized MMT cells completely removed NO3− upon 8th day with AgNPs synthesis ranging from 23.26 to 58.14. Immobilized NAP exhibited lower efficiency with 28.6% of NO3 elimination and large aggregated AgNPs ranging from 94.44 nm to 172.22 nm.
The periplasmic nitrate reductase enzyme (NAP) has become attractive catalyst, whose exploitation has emerged as one of the indispensable strategies toward environmentally benign applications. To achieve them efficiently and overcome the sensitivity of NAP in harsh environmental circumstances, the immobilization for denitrifying bacteria and NAP enzyme for simultaneous bioremediation and bionanoparticles synthesis was studied. NAP catalyzed NO3− reduction at Vmax of 0.811 μM/min and Km of 14.02 mM. Concurrently, the immobilized MMT cells completely removed NO3- upon 192 h with AgNPs synthesis ranging from 23.26 to 58.14 nm as indicated by SEM. Wherase, immobilized NAP exhibited lower efficiency with 28.6% of NO3− elimination within 288 h and large aggregated AgNPs ranging from 94.44 nm to 172.22 nm. To the best of author knowledge, the immobilization for denitrifying bacteria and NAP enzyme for simultaneous bioremediation and bionanoparticles synthesis was not studied before.
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Affiliation(s)
- Marwa Eltarahony
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934 Borgelarab, Alexandria, Egypt
| | - Sahar Zaki
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934 Borgelarab, Alexandria, Egypt
| | - Zeinab Kheiralla
- Botany Department, College of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt
| | - Desouky Abd-El-Haleem
- Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934 Borgelarab, Alexandria, Egypt
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121
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Pseudomonas aeruginosa gshA Mutant Is Defective in Biofilm Formation, Swarming, and Pyocyanin Production. mSphere 2018; 3:3/2/e00155-18. [PMID: 29669887 PMCID: PMC5907650 DOI: 10.1128/msphere.00155-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 03/24/2018] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous bacterium that can cause severe opportunistic infections, including many hospital-acquired infections. It is also a major cause of infections in patients with cystic fibrosis. P. aeruginosa is intrinsically resistant to a number of drugs and is capable of forming biofilms that are difficult to eradicate with antibiotics. The number of drug-resistant strains is also increasing, making treatment of P. aeruginosa infections very difficult. Thus, there is an urgent need to understand how P. aeruginosa causes disease in order to find novel ways to treat infections. We show that the principal redox buffer, glutathione (GSH), is involved in intrinsic resistance to the fosfomycin and rifampin antibiotics. We further demonstrate that GSH plays a role in P. aeruginosa disease and infection, since a mutant lacking GSH has less biofilm formation, is less able to swarm, and produces less pyocyanin, a pigment associated with infection. Pseudomonas aeruginosa is a ubiquitous Gram-negative bacterium that can cause severe opportunistic infections. The principal redox buffer employed by this organism is glutathione (GSH). To assess the role of GSH in the virulence of P. aeruginosa, a number of analyses were performed using a mutant strain deficient in gshA, which does not produce GSH. The mutant strain exhibited a growth delay in minimal medium compared to the wild-type strain. Furthermore, the gshA mutant was defective in biofilm and persister cell formation and in swimming and swarming motility and produced reduced levels of pyocyanin, a key virulence factor. Finally, the gshA mutant strain demonstrated increased sensitivity to methyl viologen (a redox cycling agent) as well as the thiol-reactive antibiotics fosfomycin and rifampin. Taken together, these data suggest a key role for GSH in the virulence of P. aeruginosa. IMPORTANCEPseudomonas aeruginosa is a ubiquitous bacterium that can cause severe opportunistic infections, including many hospital-acquired infections. It is also a major cause of infections in patients with cystic fibrosis. P. aeruginosa is intrinsically resistant to a number of drugs and is capable of forming biofilms that are difficult to eradicate with antibiotics. The number of drug-resistant strains is also increasing, making treatment of P. aeruginosa infections very difficult. Thus, there is an urgent need to understand how P. aeruginosa causes disease in order to find novel ways to treat infections. We show that the principal redox buffer, glutathione (GSH), is involved in intrinsic resistance to the fosfomycin and rifampin antibiotics. We further demonstrate that GSH plays a role in P. aeruginosa disease and infection, since a mutant lacking GSH has less biofilm formation, is less able to swarm, and produces less pyocyanin, a pigment associated with infection.
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122
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Cardinale S, Tueros FG, Sommer MOA. Genetic-Metabolic Coupling for Targeted Metabolic Engineering. Cell Rep 2018; 20:1029-1037. [PMID: 28768189 DOI: 10.1016/j.celrep.2017.07.015] [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: 01/24/2017] [Revised: 05/16/2017] [Accepted: 07/07/2017] [Indexed: 12/19/2022] Open
Abstract
Production of chemicals in microbes often employs potent biosynthetic enzymes, which can interact with the microbial native metabolism to affect cell fitness and product yield. However, production optimization largely relies on data collected from wild-type strains in the absence of metabolic perturbations, thus limiting their relevance to specific conditions. Here, we address this issue by coupling cell fitness to the production of thiamine diphosphate in Escherichia coli using a synthetic RNA biosensor. We use this strategy to interrogate a library of transposon mutants and elucidate the native gene network influencing both cell fitness and thiamine production. Ultimately, we identify effectors of the OxyR-Fur stress response that limit thiamine biosynthesis via alternative regulation of iron storage and Fe-S cluster inclusion in enzymes. This study presents a new approach for the reliable high-throughput identification of genetic targets of both known and unknown function that are directly relevant to a specific biosynthetic process.
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Affiliation(s)
- Stefano Cardinale
- NNF-CFB, Technical University of Denmark, 2800 Kongens Lyngby, Denmark.
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123
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Lee HN, Ji CJ, Lee HH, Park J, Seo YS, Lee JW, Oh JI. Roles of three FurA paralogs in the regulation of genes pertaining to peroxide defense in Mycobacterium smegmatis mc 2 155. Mol Microbiol 2018; 108:661-682. [PMID: 29569300 DOI: 10.1111/mmi.13956] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2018] [Indexed: 11/28/2022]
Abstract
Mycobacterium smegmatis mc2 155 has three genes (MSMEG_6383, furA1; MSMEG_3460, furA2; MSMEG_6253, furA3) encoding FurA (ferric-uptake regulator A) paralogs. Three FurA paralogs in M. smegmatis are functionally redundant and negatively regulate expression of a subset of genes involved in peroxide detoxification such as ahpC, katG1 and katG2, as well as their own genes. The FurA paralogs sense H2 O2 via metal-catalyzed His oxidation (MCHO) in the same way as PerR. The propensity of FurA2 and FurA3 for MCHO is greater than that of FurA1. The three furA genes are transcribed into leaderless mRNAs lacking the Shine-Dalgarno (SD) sequence. FurA1 and FurA3 have the quaternary structure of homodimers like most Fur homologs, whereas FurA2 occurs as a monomer. The monomeric structure of FurA2 is determined by the C-terminal region of its dimerization domain. FurA2 monomers appear to cooperatively bind to the FurA-binding site with an inverted repeat configuration and have a broader binding specificity for the target DNA than dimeric FurA1 and FurA3. Comparative transcriptomic analysis revealed that the FurA paralogs do not regulate genes related to iron homeostasis in M. smegmatis, and that expression of SigF-regulated genes is significantly decreased in a furA triple mutant relative to the wild-type strain of M. smegmatis.
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Affiliation(s)
- Ha-Na Lee
- Department of Microbiology, Pusan National University, Busan, 46241, Korea
| | - Chang-Jun Ji
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Korea
| | - Hyun-Hee Lee
- Department of Microbiology, Pusan National University, Busan, 46241, Korea
| | - Jungwook Park
- Department of Microbiology, Pusan National University, Busan, 46241, Korea
| | - Young-Su Seo
- Department of Microbiology, Pusan National University, Busan, 46241, Korea
| | - Jin-Won Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Korea
| | - Jeong-Il Oh
- Department of Microbiology, Pusan National University, Busan, 46241, Korea
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124
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OxyR-Dependent Transcription Response of Sinorhizobium meliloti to Oxidative Stress. J Bacteriol 2018; 200:JB.00622-17. [PMID: 29358497 DOI: 10.1128/jb.00622-17] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 01/11/2018] [Indexed: 11/20/2022] Open
Abstract
Reactive oxygen species such as peroxides play an important role in plant development, cell wall maturation, and defense responses. During nodulation with the host plant Medicago sativa, Sinorhizobium meliloti cells are exposed to H2O2 in infection threads and developing nodules (R. Santos, D. Hérouart, S. Sigaud, D. Touati, and A. Puppo, Mol Plant Microbe Interact 14:86-89, 2001, https://doi.org/10.1094/MPMI.2001.14.1.86). S. meliloti cells likely also experience oxidative stress, from both internal and external sources, during life in the soil. Here, we present microarray transcription data for S. meliloti wild-type cells compared to a mutant deficient in the key oxidative regulatory protein OxyR, each in response to H2O2 treatment. Several alternative sigma factor genes are upregulated in the response to H2O2; the stress sigma gene rpoE2 shows OxyR-dependent induction by H2O2, while rpoH1 expression is induced by H2O2 irrespective of the oxyR genotype. The activity of the RpoE2 sigma factor in turn causes increased expression of two more sigma factor genes, rpoE5 and rpoH2 Strains with deletions of rpoH1 showed improved survival in H2O2 as well as increased levels of oxyR and total catalase expression. These results imply that ΔrpoH1 strains are primed to deal with oxidative stress. This work presents a global view of S. meliloti gene expression changes, and of regulation of those changes, in response to H2O2IMPORTANCE Like all aerobic organisms, the symbiotic nitrogen-fixing bacterium Sinorhizobium meliloti experiences oxidative stress throughout its complex life cycle. This report describes the global transcriptional changes that S. meliloti makes in response to H2O2 and the roles of the OxyR transcriptional regulator and the RpoH1 sigma factor in regulating those changes. By understanding the complex regulatory response of S. meliloti to oxidative stress, we may further understand the role that reactive oxygen species play as both stressors and potential signals during symbiosis.
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125
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Enhancing the Adaptability of the Deep-Sea Bacterium Shewanella piezotolerans WP3 to High Pressure and Low Temperature by Experimental Evolution under H 2O 2 Stress. Appl Environ Microbiol 2018; 84:AEM.02342-17. [PMID: 29269502 DOI: 10.1128/aem.02342-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/10/2017] [Indexed: 11/20/2022] Open
Abstract
Oxidative stresses commonly exist in natural environments, and microbes have developed a variety of defensive systems to counteract such events. Although increasing evidence has shown that high hydrostatic pressure (HHP) and low temperature (LT) induce antioxidant defense responses in cells, there is no direct evidence to prove the connection between antioxidant defense mechanisms and the adaptation of bacteria to HHP and LT. In this study, using the wild-type (WT) strain of a deep-sea bacterium, Shewanella piezotolerans WP3, as an ancestor, we obtained a mutant, OE100, with an enhanced antioxidant defense capacity by experimental evolution under H2O2 stress. Notably, OE100 exhibited better tolerance not only to H2O2 stress but also to HHP and LT (20 MPa and 4°C, respectively). Whole-genome sequencing identified a deletion mutation in the oxyR gene, which encodes the transcription factor that controls the oxidative stress response. Comparative transcriptome analysis showed that the genes associated with oxidative stress defense, anaerobic respiration, DNA repair, and the synthesis of flagella and bacteriophage were differentially expressed in OE100 compared with the WT at 20 MPa and 4°C. Genetic analysis of oxyR and ccpA2 indicated that the OxyR-regulated cytochrome c peroxidase CcpA2 significantly contributed to the adaptation of WP3 to HHP and LT. Taken together, these results confirmed the inherent relationship between antioxidant defense mechanisms and the adaptation of a benthic microorganism to HHP and LT.IMPORTANCE Oxidative stress exists in various niches, including the deep-sea ecosystem, which is an extreme environment with conditions of HHP and predominantly LT. Although previous studies have shown that HHP and LT induce antioxidant defense responses in cells, direct evidence to prove the connection between antioxidant defense mechanisms and the adaptation of bacteria to HHP and LT is lacking. In this work, using the deep-sea bacterium Shewanella piezotolerans WP3 as a model, we proved that enhancement of the adaptability of WP3 to HHP and LT can benefit from its antioxidant defense mechanism, which provided useful insight into the ecological roles of antioxidant genes in a benthic microorganism and contributed to an improved understanding of microbial adaptation strategies in deep-sea environments.
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Wan F, Kong L, Gao H. Defining the binding determinants of Shewanella oneidensis OxyR: Implications for the link between the contracted OxyR regulon and adaptation. J Biol Chem 2018; 293:4085-4096. [PMID: 29367341 DOI: 10.1074/jbc.ra117.001530] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 01/16/2018] [Indexed: 01/06/2023] Open
Abstract
It is well-established that OxyR functions as a transcriptional activator of the peroxide stress response in bacteria, primarily based on studies on Escherichia coli Recent investigations have revealed that OxyRs of some other bacteria can regulate gene expression through both repression and activation or repression only; however, the underlying mechanisms remain largely unknown. Here, we demonstrated in γ-proteobacteriumShewanella oneidensis regulation of OxyR on expression of major catalase gene katB in a dual-control manner through interaction with a single site in the promoter region. Under non-stress conditions, katB expression was repressed by reduced OxyR (OxyRred), whereas when oxidized, OxyR (OxyRoxi) outcompeted OxyRred for the site because of substantially enhanced affinity, resulting in a graded response to oxidative stress, from repression to derepression to activation. The OxyR-binding motif is characterized as a combination of the E. coli motif (tetranucleotides spaced by heptanucleotide) and palindromic structure. We provided evidence to suggest that the S. oneidensis OxyR regulon is significantly contracted compared with those reported, probably containing only five members that are exclusively involved in oxygen reactive species scavenging and iron sequestering. These characteristics probably reflect the adapting strategy of the bacteria that S. oneidensis represents to thrive in redox-stratified microaerobic and anaerobic environments.
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Affiliation(s)
- Fen Wan
- From the Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Linggen Kong
- From the Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Haichun Gao
- From the Institute of Microbiology and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Park SC, Kwak YM, Song WS, Hong M, Yoon SI. Structural basis of effector and operator recognition by the phenolic acid-responsive transcriptional regulator PadR. Nucleic Acids Res 2018; 45:13080-13093. [PMID: 29136175 PMCID: PMC5728393 DOI: 10.1093/nar/gkx1055] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 10/19/2017] [Indexed: 12/24/2022] Open
Abstract
The PadR family is a large group of transcriptional regulators that function as environmental sensors. PadR negatively controls the expression of phenolic acid decarboxylase, which detoxifies harmful phenolic acids. To identify the mechanism by which PadR regulates phenolic acid-mediated gene expression, we performed structural and mutational studies of effector and operator recognition by Bacillus subtilis PadR. PadR contains an N-terminal winged helix-turn-helix (wHTH) domain (NTD) and a C-terminal homodimerization domain (CTD) and dimerizes into a dolmen shape. The PadR dimer interacts with the palindromic sequence of the operator DNA using the NTD. Two tyrosine residues and a positively charged residue in the NTD provide major DNA-binding energy and are highly conserved in the PadR family, suggesting that these three residues represent the canonical DNA-binding motif of the PadR family. PadR directly binds a phenolic acid effector molecule using a unique interdomain pocket created between the NTD and the CTD. Although the effector-binding site of PadR is positionally segregated from the DNA-binding site, effector binding to the interdomain pocket causes PadR to be rearranged into a DNA binding-incompatible conformer through an allosteric interdomain-reorganization mechanism.
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Affiliation(s)
- Sun Cheol Park
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Yun Mi Kwak
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Wan Seok Song
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Minsun Hong
- Division of Biological Science and Technology, Yonsei University, Wonju 26493, Republic of Korea
| | - Sung-Il Yoon
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon 24341, Republic of Korea.,Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon 24341, Republic of Korea
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128
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The metabolic enzyme fructose-1,6-bisphosphate aldolase acts as a transcriptional regulator in pathogenic Francisella. Nat Commun 2017; 8:853. [PMID: 29021545 PMCID: PMC5636795 DOI: 10.1038/s41467-017-00889-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 08/02/2017] [Indexed: 12/31/2022] Open
Abstract
The enzyme fructose-bisphosphate aldolase occupies a central position in glycolysis and gluconeogenesis pathways. Beyond its housekeeping role in metabolism, fructose-bisphosphate aldolase has been involved in additional functions and is considered as a potential target for drug development against pathogenic bacteria. Here, we address the role of fructose-bisphosphate aldolase in the bacterial pathogen Francisella novicida. We demonstrate that fructose-bisphosphate aldolase is important for bacterial multiplication in macrophages in the presence of gluconeogenic substrates. In addition, we unravel a direct role of this metabolic enzyme in transcription regulation of genes katG and rpoA, encoding catalase and an RNA polymerase subunit, respectively. We propose a model in which fructose-bisphosphate aldolase participates in the control of host redox homeostasis and the inflammatory immune response.The enzyme fructose-bisphosphate aldolase (FBA) plays central roles in glycolysis and gluconeogenesis. Here, Ziveri et al. show that FBA of the pathogen Francisella novicida acts, in addition, as a transcriptional regulator and is important for bacterial multiplication in macrophages.
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129
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Wang P, Lee Y, Igo MM, Roper MC. Tolerance to oxidative stress is required for maximal xylem colonization by the xylem-limited bacterial phytopathogen, Xylella fastidiosa. MOLECULAR PLANT PATHOLOGY 2017; 18:990-1000. [PMID: 27377476 PMCID: PMC6638236 DOI: 10.1111/mpp.12456] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/24/2016] [Accepted: 06/28/2016] [Indexed: 05/07/2023]
Abstract
Bacterial plant pathogens often encounter reactive oxygen species (ROS) during host invasion. In foliar bacterial pathogens, multiple regulatory proteins are involved in the sensing of oxidative stress and the activation of the expression of antioxidant genes. However, it is unclear whether xylem-limited bacteria, such as Xylella fastidiosa, experience oxidative stress during the colonization of plants. Examination of the X. fastidiosa genome uncovered only one homologue of oxidative stress regulatory proteins, OxyR. Here, a knockout mutation in the X. fastidiosa oxyR gene was constructed; the resulting strain was significantly more sensitive to hydrogen peroxide (H2 O2 ) relative to the wild-type. In addition, during early stages of grapevine infection, the survival rate was 1000-fold lower for the oxyR mutant than for the wild-type. This supports the hypothesis that grapevine xylem represents an oxidative environment and that X. fastidiosa must overcome this challenge to achieve maximal xylem colonization. Finally, the oxyR mutant exhibited reduced surface attachment and cell-cell aggregation and was defective in biofilm maturation, suggesting that ROS could be a potential environmental cue stimulating biofilm development during the early stages of host colonization.
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Affiliation(s)
- Peng Wang
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA92521USA
| | - Yunho Lee
- Department of Microbiology and Molecular GeneticsUniversity of CaliforniaDavisCA95616USA
| | - Michele M. Igo
- Department of Microbiology and Molecular GeneticsUniversity of CaliforniaDavisCA95616USA
| | - M. Caroline Roper
- Department of Plant Pathology and MicrobiologyUniversity of CaliforniaRiversideCA92521USA
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Lethality of MalE-LacZ hybrid protein shares mechanistic attributes with oxidative component of antibiotic lethality. Proc Natl Acad Sci U S A 2017; 114:9164-9169. [PMID: 28794281 DOI: 10.1073/pnas.1707466114] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Downstream metabolic events can contribute to the lethality of drugs or agents that interact with a primary cellular target. In bacteria, the production of reactive oxygen species (ROS) has been associated with the lethal effects of a variety of stresses including bactericidal antibiotics, but the relative contribution of this oxidative component to cell death depends on a variety of factors. Experimental evidence has suggested that unresolvable DNA problems caused by incorporation of oxidized nucleotides into nascent DNA followed by incomplete base excision repair contribute to the ROS-dependent component of antibiotic lethality. Expression of the chimeric periplasmic-cytoplasmic MalE-LacZ72-47 protein is an historically important lethal stress originally identified during seminal genetic experiments that defined the SecY-dependent protein translocation system. Multiple, independent lines of evidence presented here indicate that the predominant mechanism for MalE-LacZ lethality shares attributes with the ROS-dependent component of antibiotic lethality. MalE-LacZ lethality requires molecular oxygen, and its expression induces ROS production. The increased susceptibility of mutants sensitive to oxidative stress to MalE-LacZ lethality indicates that ROS contribute causally to cell death rather than simply being produced by dying cells. Observations that support the proposed mechanism of cell death include MalE-LacZ expression being bacteriostatic rather than bactericidal in cells that overexpress MutT, a nucleotide sanitizer that hydrolyzes 8-oxo-dGTP to the monophosphate, or that lack MutM and MutY, DNA glycosylases that process base pairs involving 8-oxo-dGTP. Our studies suggest stress-induced physiological changes that favor this mode of ROS-dependent death.
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131
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Sporer AJ, Kahl LJ, Price-Whelan A, Dietrich LE. Redox-Based Regulation of Bacterial Development and Behavior. Annu Rev Biochem 2017; 86:777-797. [DOI: 10.1146/annurev-biochem-061516-044453] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Abigail J. Sporer
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Lisa J. Kahl
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Alexa Price-Whelan
- Department of Biological Sciences, Columbia University, New York, NY 10027
| | - Lars E.P. Dietrich
- Department of Biological Sciences, Columbia University, New York, NY 10027
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132
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Meristem Plant Cells as a Sustainable Source of Redox Actives for Skin Rejuvenation. Biomolecules 2017; 7:biom7020040. [PMID: 28498360 PMCID: PMC5485729 DOI: 10.3390/biom7020040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/03/2017] [Accepted: 05/08/2017] [Indexed: 12/30/2022] Open
Abstract
Recently, aggressive advertisement claimed a “magic role” for plant stem cells in human skin rejuvenation. This review aims to shed light on the scientific background suggesting feasibility of using plant cells as a basis of anti-age cosmetics. When meristem cell cultures obtained from medicinal plants are exposed to appropriate elicitors/stressors (ultraviolet, ultrasound ultraviolet (UV), ultrasonic waves, microbial/insect metabolites, heavy metals, organic toxins, nutrient deprivation, etc.), a protective/adaptive response initiates the biosynthesis of secondary metabolites. Highly bioavailable and biocompatible to human cells, low-molecular weight plant secondary metabolites share structural/functional similarities with human non-protein regulatory hormones, neurotransmitters, pigments, polyamines, amino-/fatty acids. Their redox-regulated biosynthesis triggers in turn plant cell antioxidant and detoxification molecular mechanisms resembling human cell pathways. Easily isolated in relatively large quantities from contaminant-free cell cultures, plant metabolites target skin ageing mechanisms, above all redox imbalance. Perfect modulators of cutaneous oxidative state via direct/indirect antioxidant action, free radical scavenging, UV protection, and transition-metal chelation, they are ideal candidates to restore photochemical/redox/immune/metabolic barriers, gradually deteriorating in the ageing skin. The industrial production of plant meristem cell metabolites is toxicologically and ecologically sustainable for fully “biological” anti-age cosmetics.
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133
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Li Z, Tan J, Shao L, Dong X, Ye RD, Chen D. Selenium-mediated protection in reversing the sensitivity of bacterium to the bactericidal antibiotics. J Trace Elem Med Biol 2017; 41:23-31. [PMID: 28347459 DOI: 10.1016/j.jtemb.2017.02.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 01/12/2017] [Accepted: 02/08/2017] [Indexed: 02/07/2023]
Abstract
Inducing production of damaging reactive oxygen species (ROS) is an important criterion to distinguish the bactericidal antibiotics from bacteriostatic antibiotics. Selenoenzymes were generally recognized to be a powerful antioxidant capable of scavenging free radicals, protecting the cells from the harmful effects of ROS. Therefore, the present study was carried out to investigate the selenium (Se)-mediated protection in reversing antibiotic sensitivity and the role of selenoenzymes in alleviating the negative effects of oxidative stress. The cellular antioxidant activity of Se-enriched bacteria was analyzed, as well as intracellular ROS production and elimination when Se-enriched bacteria in the presence of various antibiotics. Compared to complete inhibition of the parental strain by bactericidal antibiotics, it only exhibited slight and reversible inhibition of Se-enriched Escherichia coli ATCC25922 and Staphylococcus aureus ATCC25923 at the same conditions, which indicated that intracellular selenium provided substantial protection against antibiotics. ROS generation caused by bactericidal antibiotics was confirmed by fluorescence spectrophotometry using 2', 7'-dichloro- uorescein diacetate (DCFH-DA) as substrate. The time course experiments of pretreatment with selenium showed significant decrease of ROS level at 2h. In summary, the present study provides experimental evidence supporting selenoenzymes has good scavenging effect to ROS and can protect bacteria from oxidative stress injury induced by bactericidal antibiotics.
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Affiliation(s)
- Zhonglei Li
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; China State Institute of Pharmaceutical Industry, Shanghai Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Jun Tan
- China State Institute of Pharmaceutical Industry, Shanghai Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Lei Shao
- China State Institute of Pharmaceutical Industry, Shanghai Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Xiaojing Dong
- China State Institute of Pharmaceutical Industry, Shanghai Institute of Pharmaceutical Industry, Shanghai 201203, China
| | - Richard D Ye
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Daijie Chen
- School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; China State Institute of Pharmaceutical Industry, Shanghai Institute of Pharmaceutical Industry, Shanghai 201203, China.
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Kim JH, Yang YM, Ji CJ, Ryu SH, Won YB, Ju SY, Kwon Y, Lee YE, Youn H, Lee JW. The inability of Bacillus licheniformis perR mutant to grow is mainly due to the lack of PerR-mediated fur repression. J Microbiol 2017; 55:457-463. [PMID: 28434086 DOI: 10.1007/s12275-017-7051-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/27/2017] [Accepted: 02/27/2017] [Indexed: 11/25/2022]
Abstract
PerR, a member of Fur family protein, is a metal-dependent H2O2 sensing transcription factor that regulates genes involved in peroxide stress response. Industrially important bacterium Bacillus licheniformis contains three PerR-like proteins (PerRBL, PerR2, and PerR3) compared to its close relative Bacillus subtilis. Interestingly, unlike other bacteria including B. subtilis, no authentic perR BL null mutant could be established for B. licheniformis. Thus, we constructed a conditional perR BL mutant using a xylose-inducible promoter, and investigated the genes under the control of PerRBL. PerRBL regulon genes include katA, mrgA, ahpC, pfeT, hemA, fur, and perR as observed for PerRBS. However, there is some variation in the expression levels of fur and hemA genes between B. subtilis and B. licheniformis in the derepressed state. Furthermore, katA, mrgA, and ahpC are strongly induced, whereas the others are only weakly or not induced by H2O2 treatment. In contrast to the B. subtilis perR null mutant which frequently gives rise to large colony phenotype mainly due to the loss of katA, the suppressors of B. licheniformis perR mutant, which can form colonies on LB agar, were all catalase-positive. Instead, many of the suppressors showed increased levels of siderophore production, suggesting that the suppressor mutation is linked to the fur gene. Consistent with this, perR fur double mutant could grow on LB agar without Fe supplementation, whereas perR katA double mutant could only grow on LB agar with Fe supplementation. Taken together, our data suggest that in B. licheniformis, despite the similarity in PerRBL and PerRBS regulon genes, perR is an essential gene required for growth and that the inability of perR null mutant to grow is mainly due to elevated expression of Fur.
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Affiliation(s)
- Jung-Hoon Kim
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yoon-Mo Yang
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Chang-Jun Ji
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Su-Hyun Ryu
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Young-Bin Won
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Shin-Yeong Ju
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yumi Kwon
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yeh-Eun Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea
| | - Hwan Youn
- Department of Biology, California State University Fresno, Fresno, CA, 93740-8034, USA.
| | - Jin-Won Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul, 04763, Republic of Korea.
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Molina-García L, Moreno-Del Álamo M, Botias P, Martín-Moldes Z, Fernández M, Sánchez-Gorostiaga A, Alonso-Del Valle A, Nogales J, García-Cantalejo J, Giraldo R. Outlining Core Pathways of Amyloid Toxicity in Bacteria with the RepA-WH1 Prionoid. Front Microbiol 2017; 8:539. [PMID: 28421043 PMCID: PMC5378768 DOI: 10.3389/fmicb.2017.00539] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/14/2017] [Indexed: 12/14/2022] Open
Abstract
The synthetic bacterial prionoid RepA-WH1 causes a vertically transmissible amyloid proteinopathy in Escherichia coli that inhibits growth and eventually kills the cells. Recent in vitro studies show that RepA-WH1 builds pores through model lipid membranes, suggesting a possible mechanism for bacterial cell death. By comparing acutely (A31V) and mildly (ΔN37) cytotoxic mutant variants of the protein, we report here that RepA-WH1(A31V) expression decreases the intracellular osmotic pressure and compromise bacterial viability under either aerobic or anaerobic conditions. Both are effects expected from threatening membrane integrity and are in agreement with findings on the impairment by RepA-WH1(A31V) of the proton motive force (PMF)-dependent transport of ions (Fe3+) and ATP synthesis. Systems approaches reveal that, in aerobiosis, the PMF-independent respiratory dehydrogenase NdhII is induced in response to the reduction in intracellular levels of iron. While NdhII is known to generate H2O2 as a by-product of the autoxidation of its FAD cofactor, key proteins in the defense against oxidative stress (OxyR, KatE), together with other stress-resistance factors, are sequestered by co-aggregation with the RepA-WH1(A31V) amyloid. Our findings suggest a route for RepA-WH1 toxicity in bacteria: a primary hit of damage to the membrane, compromising bionergetics, triggers a stroke of oxidative stress, which is exacerbated due to the aggregation-dependent inactivation of enzymes and transcription factors that enable the cellular response to such injury. The proteinopathy caused by the prion-like protein RepA-WH1 in bacteria recapitulates some of the core hallmarks of human amyloid diseases.
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Affiliation(s)
- Laura Molina-García
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - María Moreno-Del Álamo
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Pedro Botias
- Genomics Unit, Complutense UniversityMadrid, Spain
| | - Zaira Martín-Moldes
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - María Fernández
- Proteomics Facility, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Alicia Sánchez-Gorostiaga
- Department of Microbial Biotechnology, National Centre for Biotechnology, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Aída Alonso-Del Valle
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | - Juan Nogales
- Department of Environmental Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
| | | | - Rafael Giraldo
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones CientíficasMadrid, Spain
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136
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Sies H. Hydrogen peroxide as a central redox signaling molecule in physiological oxidative stress: Oxidative eustress. Redox Biol 2017; 11:613-619. [PMID: 28110218 PMCID: PMC5256672 DOI: 10.1016/j.redox.2016.12.035] [Citation(s) in RCA: 1441] [Impact Index Per Article: 205.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 12/09/2016] [Accepted: 12/16/2016] [Indexed: 11/29/2022] Open
Abstract
Hydrogen peroxide emerged as major redox metabolite operative in redox sensing, signaling and redox regulation. Generation, transport and capture of H2O2 in biological settings as well as their biological consequences can now be addressed. The present overview focuses on recent progress on metabolic sources and sinks of H2O2 and on the role of H2O2 in redox signaling under physiological conditions (1-10nM), denoted as oxidative eustress. Higher concentrations lead to adaptive stress responses via master switches such as Nrf2/Keap1 or NF-κB. Supraphysiological concentrations of H2O2 (>100nM) lead to damage of biomolecules, denoted as oxidative distress. Three questions are addressed: How can H2O2 be assayed in the biological setting? What are the metabolic sources and sinks of H2O2? What is the role of H2O2 in redox signaling and oxidative stress?
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Affiliation(s)
- Helmut Sies
- Institute of Biochemistry and Molecular Biology I, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; Leibniz Institute for Research in Environmental Medicine, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
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137
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Boonma S, Romsang A, Duang-Nkern J, Atichartpongkul S, Trinachartvanit W, Vattanaviboon P, Mongkolsuk S. The FinR-regulated essential gene fprA, encoding ferredoxin NADP+ reductase: Roles in superoxide-mediated stress protection and virulence of Pseudomonas aeruginosa. PLoS One 2017; 12:e0172071. [PMID: 28187184 PMCID: PMC5302815 DOI: 10.1371/journal.pone.0172071] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/30/2017] [Indexed: 11/23/2022] Open
Abstract
Pseudomonas aeruginosa has two genes encoding ferredoxin NADP(+) reductases, denoted fprA and fprB. We show here that P. aeruginosa fprA is an essential gene. However, the ΔfprA mutant could only be successfully constructed in PAO1 strains containing an extra copy of fprA on a mini-Tn7 vector integrated into the chromosome or carrying it on a temperature-sensitive plasmid. The strain containing an extra copy of the ferredoxin gene (fdx1) could suppress the essentiality of FprA. Other ferredoxin genes could not suppress the requirement for FprA, suggesting that Fdx1 mediates the essentiality of FprA. The expression of fprA was highly induced in response to treatments with a superoxide generator, paraquat, or sodium hypochlorite (NaOCl). The induction of fprA by these treatments depended on FinR, a LysR-family transcription regulator. In vivo and in vitro analysis suggested that oxidized FinR acted as a transcriptional activator of fprA expression by binding to its regulatory box, located 20 bases upstream of the fprA -35 promoter motif. This location of the FinR box also placed it between the -35 and -10 motifs of the finR promoter, where the reduced regulator functions as a repressor. Under uninduced conditions, binding of FinR repressed its own transcription but had no effect on fprA expression. Exposure to paraquat or NaOCl converted FinR to a transcriptional activator, leading to the expression of both fprA and finR. The ΔfinR mutant showed an increased paraquat sensitivity phenotype and attenuated virulence in the Drosophila melanogaster host model. These phenotypes could be complemented by high expression of fprA, indicating that the observed phenotypes of the ΔfinR mutant arose from the inability to up-regulate fprA expression. In addition, increased expression of fprB was unable to rescue essentiality of fprA or the superoxide-sensitive phenotype of the ΔfinR mutant, suggesting distinct mechanisms of the FprA and FprB enzymes.
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Affiliation(s)
- Siriwan Boonma
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Adisak Romsang
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Jintana Duang-Nkern
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand
| | | | | | - Paiboon Vattanaviboon
- Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.,Center of Excellence on Environmental Health and Toxicology, CHE, Ministry Of Education, Bangkok, Thailand.,Program in Applied Biological Sciences: Environmental Health, Chulabhorn Graduate Institute, Bangkok, Thailand
| | - Skorn Mongkolsuk
- Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok, Thailand.,Center of Excellence on Environmental Health and Toxicology, CHE, Ministry Of Education, Bangkok, Thailand.,Center for Emerging Bacterial Infections, Faculty of Science, Mahidol University, Bangkok, Thailand
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138
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Charbon G, Campion C, Chan SHJ, Bjørn L, Weimann A, da Silva LCN, Jensen PR, Løbner-Olesen A. Re-wiring of energy metabolism promotes viability during hyperreplication stress in E. coli. PLoS Genet 2017; 13:e1006590. [PMID: 28129339 PMCID: PMC5302844 DOI: 10.1371/journal.pgen.1006590] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 02/10/2017] [Accepted: 01/18/2017] [Indexed: 11/23/2022] Open
Abstract
Chromosome replication in Escherichia coli is initiated by DnaA. DnaA binds ATP which is essential for formation of a DnaA-oriC nucleoprotein complex that promotes strand opening, helicase loading and replisome assembly. Following initiation, DnaAATP is converted to DnaAADP primarily by the Regulatory Inactivation of DnaA process (RIDA). In RIDA deficient cells, DnaAATP accumulates leading to uncontrolled initiation of replication and cell death by accumulation of DNA strand breaks. Mutations that suppress RIDA deficiency either dampen overinitiation or permit growth despite overinitiation. We characterize mutations of the last group that have in common that distinct metabolic routes are rewired resulting in the redirection of electron flow towards the cytochrome bd-1. We propose a model where cytochrome bd-1 lowers the formation of reactive oxygen species and hence oxidative damage to the DNA in general. This increases the processivity of replication forks generated by overinitiation to a level that sustains viability. In most bacteria chromosome replication is initiated by the DnaA protein. In Escherichia coli, DnaA binds ATP and ADP with similar affinity but only the ATP bound form is active. An increased level of DnaAATP causes overinitiation and cell death by accumulation of DNA strand breaks. These strand breaks often result from forks encountering gapped DNA formed during repair of oxidative damage. We provide evidence that cell death in overinitiating cells can be prevented by rewiring the metabolism to favor the micro-aerobic respiratory chain with the cytochrome bd-1 as terminal oxidase. Cytochrome bd-1 is found in aerobic as well as anaerobic bacteria. Its role is to reduce O2 in micro-aerobic conditions and work as an electron sink to prevent the formation of reactive oxygen species. Our results suggest that bacteria can cope with replication stress by increasing respiration through cytochrome bd-1 to reduce the formation of reactive oxygen species, and hence oxidative damage to a level that does not interfere with replication fork progression.
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Affiliation(s)
- Godefroid Charbon
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Christopher Campion
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Siu Hung Joshua Chan
- National Food Institute, Microbial Biotechnology and Biorefining, Technical University of Denmark, Lyngby, Denmark
| | - Louise Bjørn
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Allan Weimann
- Laboratory of Clinical Pharmacology, Rigshospitalet, Section Q7642, Copenhagen Denmark and Department of Clinical Pharmacology, Bispebjerg Frederiksberg Hospitals, Copenhagen Denmark
| | - Luís Cláudio Nascimento da Silva
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
| | - Peter Ruhdal Jensen
- National Food Institute, Microbial Biotechnology and Biorefining, Technical University of Denmark, Lyngby, Denmark
| | - Anders Løbner-Olesen
- Dept. of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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139
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Kim JH, Won YB, Ji CJ, Yang YM, Ryu SH, Ju SY, Kwon Y, Lee YE, Lee JW. The difference in in vivo sensitivity between Bacillus licheniformis PerR and Bacillus subtilis PerR is due to the different cellular environments. Biochem Biophys Res Commun 2017; 484:125-131. [PMID: 28104400 DOI: 10.1016/j.bbrc.2017.01.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/16/2022]
Abstract
PerR, a member of Fur family of metal-dependent regulators, is a major peroxide sensor in many Gram positive bacteria, and controls the expression of genes involved in peroxide resistance. Bacillus licheniformis, a close relative to the well-studied model organism Bacillus subtilis, contains three PerR-like proteins (PerRBL, PerR2 and PerR3) in addition to Fur and Zur. In the present study, we characterized the role of PerRBL in B. licheniformis. In vitro and in vivo studies indicate that PerRBL, like PerRBS, uses either Fe2+ or Mn2+ as a corepressor and only the Fe2+-bound form of PerRBL senses low levels of H2O2 by iron-mediated histidine oxidation. Interestingly, regardless of the difference in H2O2 sensitivity, if any, between PerRBL and PerRBS, B. licheniformis expressing PerRBL or PerRBS could sense lower levels of H2O2 and was more sensitive to H2O2 than B. subtilis expressing PerRBL or PerRBS. This result suggests that the differences in cellular milieu between B. subtilis and B. licheniformis, rather than the intrinsic differences in PerRBS and PerRBLper se, affect the H2O2 sensing ability of PerR inside the cell and the H2O2 resistance of cell. In contrast, B. licheniformis and B. subtilis expressing Staphylococcus aureus PerR (PerRSA), which is more sensitive to H2O2 than PerRBL and PerRBS, were more resistant to H2O2 than those expressing either PerRBL or PerRBS. This result indicates that the sufficient difference in H2O2 susceptibility of PerR proteins can override the difference in cellular environment and affect the resistance of cell to H2O2.
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Affiliation(s)
- Jung-Hoon Kim
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Young-Bin Won
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Chang-Jun Ji
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Yoon-Mo Yang
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Su-Hyun Ryu
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Shin-Yeong Ju
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Yumi Kwon
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Yeh-Eun Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Jin-Won Lee
- Department of Life Science and Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea.
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140
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Kim J, Park C, Imlay JA, Park W. Lineage-specific SoxR-mediated Regulation of an Endoribonuclease Protects Non-enteric Bacteria from Redox-active Compounds. J Biol Chem 2017; 292:121-133. [PMID: 27895125 PMCID: PMC5217672 DOI: 10.1074/jbc.m116.757500] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/17/2016] [Indexed: 11/06/2022] Open
Abstract
Bacteria use redox-sensitive transcription factors to coordinate responses to redox stress. The [2Fe-2S] cluster-containing transcription factor SoxR is particularly tuned to protect cells against redox-active compounds (RACs). In enteric bacteria, SoxR is paired with a second transcription factor, SoxS, that activates downstream effectors. However, SoxS is absent in non-enteric bacteria, raising questions as to how SoxR functions. Here, we first show that SoxR of Acinetobacter oleivorans displayed similar activation profiles in response to RACs as did its homolog from Escherichia coli but controlled a different set of target genes, including sinE, which encodes an endoribonuclease. Expression, gel mobility shift, and mutational analyses indicated that sinE is a direct target of SoxR. Redox potentials and permeability of RACs determined optimal sinE induction. Bioinformatics suggested that only a few γ- and β-proteobacteria might have SoxR-regulated sinE Purified SinE, in the presence of Mg2+ ions, degrades rRNAs, thus inhibiting protein synthesis. Similarly, pretreatment of cells with RACs demonstrated a role for SinE in promoting persistence in the presence of antibiotics that inhibit protein synthesis. Our data improve our understanding of the physiology of soil microorganisms by suggesting that both non-enteric SoxR and its target SinE play protective roles in the presence of RACs and antibiotics.
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Affiliation(s)
- Jisun Kim
- From the Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Korea and
| | - Chulwoo Park
- From the Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Korea and
| | - James A Imlay
- the Department of Microbiology, University of Illinois, Urbana, Illinois 61801
| | - Woojun Park
- From the Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Korea and
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141
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Biological and Chemical Adaptation to Endogenous Hydrogen Peroxide Production in Streptococcus pneumoniae D39. mSphere 2017; 2:mSphere00291-16. [PMID: 28070562 PMCID: PMC5214746 DOI: 10.1128/msphere.00291-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/04/2016] [Indexed: 12/29/2022] Open
Abstract
Adaptation to endogenous oxidative stress is an integral aspect of Streptococcus pneumoniae colonization and virulence. In this work, we identify key transcriptomic and proteomic features of the pneumococcal endogenous oxidative stress response. The thiol peroxidase TpxD plays a critical role in adaptation to endogenous H2O2 and serves to limit protein sulfenylation of glycolytic, capsule, and nucleotide biosynthesis enzymes in S. pneumoniae. The catalase-negative, facultative anaerobe Streptococcus pneumoniae D39 is naturally resistant to hydrogen peroxide (H2O2) produced endogenously by pyruvate oxidase (SpxB). Here, we investigate the adaptive response to endogenously produced H2O2. We show that lactate oxidase, which converts lactate to pyruvate, positively impacts pyruvate flux through SpxB and that ΔlctO mutants produce significantly lower H2O2. In addition, both the SpxB pathway and a candidate pyruvate dehydrogenase complex (PDHC) pathway contribute to acetyl coenzyme A (acetyl-CoA) production during aerobic growth, and the pyruvate format lyase (PFL) pathway is the major acetyl-CoA pathway during anaerobic growth. Microarray analysis of the D39 strain cultured under aerobic versus strict anaerobic conditions shows upregulation of spxB, a gene encoding a rhodanese-like protein (locus tag spd0091), tpxD, sodA, piuB, piuD, and an Fe-S protein biogenesis operon under H2O2-producing conditions. Proteome profiling of H2O2-induced sulfenylation reveals that sulfenylation levels correlate with cellular H2O2 production, with endogenous sulfenylation of ≈50 proteins. Deletion of tpxD increases cellular sulfenylation 5-fold and has an inhibitory effect on ATP generation. Two major targets of protein sulfenylation are glyceraldehyde-3-phosphate dehydrogenase (GapA) and SpxB itself, but targets also include pyruvate kinase, LctO, AdhE, and acetate kinase (AckA). Sulfenylation of GapA is inhibitory, while the effect on SpxB activity is negligible. Strikingly, four enzymes of capsular polysaccharide biosynthesis are sulfenylated, as are enzymes associated with nucleotide biosynthesis via ribulose-5-phosphate. We propose that LctO/SpxB-generated H2O2 functions as a signaling molecule to downregulate capsule production and drive altered flux through sugar utilization pathways. IMPORTANCE Adaptation to endogenous oxidative stress is an integral aspect of Streptococcus pneumoniae colonization and virulence. In this work, we identify key transcriptomic and proteomic features of the pneumococcal endogenous oxidative stress response. The thiol peroxidase TpxD plays a critical role in adaptation to endogenous H2O2 and serves to limit protein sulfenylation of glycolytic, capsule, and nucleotide biosynthesis enzymes in S. pneumoniae.
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142
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Regulation of Gene and Protein Expression in the Lyme Disease Spirochete. Curr Top Microbiol Immunol 2017; 415:83-112. [PMID: 29064060 DOI: 10.1007/82_2017_49] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The infectious cycle of Borrelia burgdorferi necessitates persistent infection of both vertebrates and ticks, and efficient means of transmission between those two very different types of hosts. The Lyme disease spirochete has evolved mechanisms to sense its location in the infectious cycle, and use that information to control production of the proteins and other factors required for each step. Numerous components of borrelial regulatory pathways have been characterized to date. Their effects are being pieced together, thereby providing glimpses into a complex web of cooperative and antagonistic interactions. In this chapter, we present a broad overview of B. burgdorferi gene and protein regulation during the natural infectious cycle, discussions of culture-based methods for elucidating regulatory mechanisms, and summaries of many of the known regulatory proteins and small molecules. We also highlight areas that are in need of substantially more research.
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143
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OxyR-regulated catalase CatB promotes the virulence in rice via detoxifying hydrogen peroxide in Xanthomonas oryzae pv. oryzae. BMC Microbiol 2016; 16:269. [PMID: 27825304 PMCID: PMC5101826 DOI: 10.1186/s12866-016-0887-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 11/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To facilitate infection, Xanthomonas oryzae pv. oryzae (Xoo), the bacterial blight pathogen of rice, needs to degrade hydrogen peroxide (H2O2) generated by the host defense response via a mechanism that is mediated by the transcriptional regulator OxyR. The catalase (CAT) gene catB has previously been shown to belong to the OxyR regulon in Xoo. However, its expression patterns and function in H2O2 detoxification and bacterial pathogenicity on rice remain to be elucidated. RESULTS The catB gene encodes a putative catalase and is highly conserved in the sequenced strains of Xanthomonas spp. β-galactosidase analysis and electrophoretic mobility shift assays (EMSA) showed that OxyR positively regulated the transcription of catB by directly binding to its promoter region. The quantitative real-time PCR (qRT-PCR) assays revealed that the expression levels of catB and oxyR were significantly induced by H2O2. Deletion of catB or oxyR drastically impaired bacterial viability in the presence of extracellular H2O2 and reduced CAT activity, demonstrating that CatB and OxyR contribute to H2O2 detoxification in Xoo. In addition, ΔcatB and ΔoxyR displayed shorter bacterial blight lesions and reduced bacterial growth in rice compared to the wild-type stain, indicating that CatB and OxyR play essential roles in the virulence of Xoo. CONCLUSIONS Transcription of catB is enhanced by OxyR in response to exogenous H2O2. CatB functions as an active catalase that is required for the full virulence of Xoo in rice.
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144
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Petkau K, Fast D, Duggal A, Foley E. Comparative evaluation of the genomes of three common Drosophila-associated bacteria. Biol Open 2016; 5:1305-16. [PMID: 27493201 PMCID: PMC5051641 DOI: 10.1242/bio.017673] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Drosophila melanogaster is an excellent model to explore the molecular exchanges that occur between an animal intestine and associated microbes. Previous studies in Drosophila uncovered a sophisticated web of host responses to intestinal bacteria. The outcomes of these responses define critical events in the host, such as the establishment of immune responses, access to nutrients, and the rate of larval development. Despite our steady march towards illuminating the host machinery that responds to bacterial presence in the gut, there are significant gaps in our understanding of the microbial products that influence bacterial association with a fly host. We sequenced and characterized the genomes of three common Drosophila-associated microbes: Lactobacillus plantarum, Lactobacillus brevis and Acetobacter pasteurianus. For each species, we compared the genomes of Drosophila-associated strains to the genomes of strains isolated from alternative sources. We found that environmental Lactobacillus strains readily associated with adult Drosophila and were similar to fly isolates in terms of genome organization. In contrast, we identified a strain of A. pasteurianus that apparently fails to associate with adult Drosophila due to an inability to grow on fly nutrient food. Comparisons between association competent and incompetent A. pasteurianus strains identified a short list of candidate genes that may contribute to survival on fly medium. Many of the gene products unique to fly-associated strains have established roles in the stabilization of host-microbe interactions. These data add to a growing body of literature that examines the microbial perspective of host-microbe relationships. Summary: We examined the genomes of Drosophila-associated bacteria to identify factors that allow survival within the host. These preliminary studies may point at bacterial products that influence host health.
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Affiliation(s)
- Kristina Petkau
- Department of Medical Microbiology and Immunology, Institute of Virology, University of Alberta, Edmonton AB, T6G 2E1 Canada
| | - David Fast
- Department of Medical Microbiology and Immunology, Institute of Virology, University of Alberta, Edmonton AB, T6G 2E1 Canada
| | - Aashna Duggal
- Department of Medical Microbiology and Immunology, Institute of Virology, University of Alberta, Edmonton AB, T6G 2E1 Canada
| | - Edan Foley
- Department of Medical Microbiology and Immunology, Institute of Virology, University of Alberta, Edmonton AB, T6G 2E1 Canada
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145
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Trautwein K, Will SE, Hulsch R, Maschmann U, Wiegmann K, Hensler M, Michael V, Ruppersberg H, Wünsch D, Feenders C, Neumann-Schaal M, Kaltenhäuser S, Ulbrich M, Schmidt-Hohagen K, Blasius B, Petersen J, Schomburg D, Rabus R. Native plasmids restrict growth of Phaeobacter inhibens DSM 17395: Energetic costs of plasmids assessed by quantitative physiological analyses. Environ Microbiol 2016; 18:4817-4829. [PMID: 27233797 DOI: 10.1111/1462-2920.13381] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Plasmid carriage is associated with energetic costs, and thus only those plasmids providing fitness benefits are stably maintained in the host lineage. Marine bacteria of the Roseobacter clade harbor up to 11 extrachromosomal replicons, adding lifestyle-relevant and possibly habitat success-promoting functions to their genomic repertoire. Phaeobacter inhibens DSM 17395 is a nutritionally versatile representative, carrying three stable and functionally distinct plasmids (65, 78, and 262 kb). The present study investigates the physiological and energetic consequences of plasmid carriage in P. inhibens DSM 17395, employing mutants cured from all native plasmids in every possible combination (seven different). Cultivation in process-controlled bioreactors with casamino acids as organic substrate revealed a complex physiological response, suggesting existence of functional interconnections between the replicons. Deletion of the 262 kb plasmid boosted growth rate (>3-fold) and growth efficiency (yields for carbon, O2 and CO2 ), which was not observed for the 65 or 78 kb plasmid. Carriage of the 262 kb plasmid was most costly for the wild type, i.e. contributing ∼50% to its energetic (dissimilatory) expenditures. Cost-benefit analysis of plasmid carriage reflects the high value of plasmids for niche specialization of P. inhibens DSM 17395 and most likely also for related Phaeobacter species.
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Affiliation(s)
- Kathleen Trautwein
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Sabine Eva Will
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Reiner Hulsch
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Uwe Maschmann
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Katharina Wiegmann
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Michael Hensler
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Victoria Michael
- Department Microbial Ecology and Diversity Projects, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Hanna Ruppersberg
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Daniel Wünsch
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Christoph Feenders
- Mathematical Modelling, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Meina Neumann-Schaal
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Sabine Kaltenhäuser
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Marcus Ulbrich
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Kerstin Schmidt-Hohagen
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Bernd Blasius
- Mathematical Modelling, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Jörn Petersen
- Department Microbial Ecology and Diversity Projects, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Dietmar Schomburg
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Carolo-Wilhelmina Braunschweig, Braunschweig, Germany
| | - Ralf Rabus
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University Oldenburg, Oldenburg, Germany
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146
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The anti-sigma factor RsrA responds to oxidative stress by reburying its hydrophobic core. Nat Commun 2016; 7:12194. [PMID: 27432510 PMCID: PMC4960319 DOI: 10.1038/ncomms12194] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 06/08/2016] [Indexed: 12/22/2022] Open
Abstract
Redox-regulated effector systems that counteract oxidative stress are essential for all forms of life. Here we uncover a new paradigm for sensing oxidative stress centred on the hydrophobic core of a sensor protein. RsrA is an archetypal zinc-binding anti-sigma factor that responds to disulfide stress in the cytoplasm of Actinobacteria. We show that RsrA utilizes its hydrophobic core to bind the sigma factor σR preventing its association with RNA polymerase, and that zinc plays a central role in maintaining this high-affinity complex. Oxidation of RsrA is limited by the rate of zinc release, which weakens the RsrA–σR complex by accelerating its dissociation. The subsequent trigger disulfide, formed between specific combinations of RsrA's three zinc-binding cysteines, precipitates structural collapse to a compact state where all σR-binding residues are sequestered back into its hydrophobic core, releasing σR to activate transcription of anti-oxidant genes. Counteracting oxidative stress is essential in all organisms. Here, the authors outline a mechanism used by actinomycete bacteria in which oxidation of zinc-binding RsrA blocks its interaction with σR by sequestering hydrophobic residues used to bind σR within its own core.
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147
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Ma Z, Russo VC, Rabadi SM, Jen Y, Catlett SV, Bakshi CS, Malik M. Elucidation of a mechanism of oxidative stress regulation in Francisella tularensis live vaccine strain. Mol Microbiol 2016; 101:856-78. [PMID: 27205902 DOI: 10.1111/mmi.13426] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2016] [Indexed: 12/21/2022]
Abstract
Francisella tularensis causes a lethal human disease known as tularemia. As an intracellular pathogen, Francisella survives and replicates in phagocytic cells, such as macrophages. However, to establish an intracellular niche, Francisella must overcome the oxidative stress posed by the reactive oxygen species (ROS) produced by the infected macrophages. OxyR and SoxR/S are two well-characterized transcriptional regulators of oxidative stress responses in several bacterial pathogens. Only the OxyR homolog is present in F. tularensis, while the SoxR homologs are absent. The functional role of OxyR has not been established in F. tularensis. We demonstrate that OxyR regulates oxidative stress responses and provides resistance against ROS, thereby contributing to the survival of the F. tularensis subsp. holarctica live vaccine strain (LVS) in macrophages and epithelial cells and contributing to virulence in mice. Proteomic analysis reveals the differential production of 128 proteins in the oxyR gene deletion mutant, indicating its global regulatory role in the oxidative stress response of F. tularensis. Moreover, OxyR regulates the transcription of the primary antioxidant enzyme genes by binding directly to their putative promoter regions. This study demonstrates that OxyR is an important virulence factor and transcriptional regulator of the oxidative stress response of the F. tularensis LVS.
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Affiliation(s)
- Zhuo Ma
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | - Vincenzo C Russo
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | - Seham M Rabadi
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA
| | - Yu Jen
- Department of Pathology, Westchester Medical Center, Valhalla, NY, USA
| | - Sally V Catlett
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
| | | | - Meenakshi Malik
- Department of Basic and Social Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, USA
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148
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Sethu R, Gouré E, Signor L, Caux-Thang C, Clémancey M, Duarte V, Latour JM. Reaction of PerR with Molecular Oxygen May Assist H2O2 Sensing in Anaerobes. ACS Chem Biol 2016; 11:1438-44. [PMID: 26963368 DOI: 10.1021/acschembio.5b01054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PerR is the peroxide resistance regulator found in several pathogenic bacteria and governs their resistance to peroxide stress by inducing enzymes that destroy peroxides. However, it has recently been implicated as a key component of the aerotolerance in several facultative or strict anaerobes, including the highly pathogenic Staphylococcus aureus. By combining (18)O labeling studies to ESI- and MALDI-TOF MS detection and EMSA experiments, we demonstrate that the active form of PerR reacts with dioxygen, which leads ultimately to disruption of the PerR/DNA complex and is thus physiologically meaningful. Moreover, we show that the presence of O2 assists PerR sensing of H2O2, another feature likely to be important for anaerobic organisms. These results allow one to envisage different scenarios for the response of anaerobes to air exposure.
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Affiliation(s)
- Ramakrishnan Sethu
- Université Grenoble Alpes, LCBM, F-38054 Grenoble, France
- CEA, DSV, BIG, LCBM, PMB, F-38054 Grenoble, France
- CNRS UMR 5249, LCBM, F-38054 Grenoble, France
| | - Eric Gouré
- Université Grenoble Alpes, LCBM, F-38054 Grenoble, France
- CEA, DSV, BIG, LCBM, PMB, F-38054 Grenoble, France
- CNRS UMR 5249, LCBM, F-38054 Grenoble, France
| | - Luca Signor
- Université Grenoble Alpes, IBS, F-38044 Grenoble, France
- CNRS, IBS, F-38044 Grenoble, France
- CEA, IBS, F-38044 Grenoble, France
| | - Christelle Caux-Thang
- Université Grenoble Alpes, LCBM, F-38054 Grenoble, France
- CEA, DSV, BIG, LCBM, PMB, F-38054 Grenoble, France
- CNRS UMR 5249, LCBM, F-38054 Grenoble, France
| | - Martin Clémancey
- Université Grenoble Alpes, LCBM, F-38054 Grenoble, France
- CEA, DSV, BIG, LCBM, PMB, F-38054 Grenoble, France
- CNRS UMR 5249, LCBM, F-38054 Grenoble, France
| | - Victor Duarte
- Université Grenoble Alpes, LCBM, F-38054 Grenoble, France
- CEA, DSV, BIG, LCBM, PMB, F-38054 Grenoble, France
- CNRS UMR 5249, LCBM, F-38054 Grenoble, France
| | - Jean-Marc Latour
- Université Grenoble Alpes, LCBM, F-38054 Grenoble, France
- CEA, DSV, BIG, LCBM, PMB, F-38054 Grenoble, France
- CNRS UMR 5249, LCBM, F-38054 Grenoble, France
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Pratte BS, Thiel T. Homologous regulators, CnfR1 and CnfR2, activate expression of two distinct nitrogenase gene clusters in the filamentous cyanobacterium Anabaena variabilis ATCC 29413. Mol Microbiol 2016; 100:1096-109. [PMID: 26950042 DOI: 10.1111/mmi.13370] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2016] [Indexed: 02/06/2023]
Abstract
The cyanobacterium Anabaena variabilis has two Mo-nitrogenases that function under different environmental conditions in different cell types. The heterocyst-specific nitrogenase encoded by the large nif1 gene cluster and the similar nif2 gene cluster that functions under anaerobic conditions in vegetative cells are under the control of the promoter for the first gene of each cluster, nifB1 or nifB2 respectively. Associated with each of these clusters is a putative regulatory gene called cnfR (patB) whose product has a C-terminal HTH domain and an N-terminal ferredoxin-like domain. CnfR1 activates nifB1 expression in heterocysts, while CnfR2 activates nifB2 expression. A cnfR1 mutant was unable to make nitrogenase under aerobic conditions in heterocysts while the cnfR2 mutant was unable to make nitrogenase under anaerobic conditions. Mutations in cnfR1 and cnfR2 reduced transcripts for the nif1 and nif2 genes respectively. The closely related cyanobacterium, Anabaena sp. PCC 7120 has the nif1 system but lacks nif2. Expression of nifB2:lacZ from A. variabilis in anaerobic vegetative cells of Anabaena sp. PCC 7120 depended on the presence of cnfR2. This suggests that CnfR2 is necessary and sufficient for activation of the nifB2 promoter and that the CnfR1/CnfR2 family of proteins are the primary activators of nitrogenase gene expression in cyanobacteria.
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Affiliation(s)
- Brenda S Pratte
- Department of Biology, University of Missouri - St. Louis, Research 223, St. Louis, MO, 63121, USA
| | - Teresa Thiel
- Department of Biology, University of Missouri - St. Louis, Research 223, St. Louis, MO, 63121, USA
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Chen S, Thompson KM, Francis MS. Environmental Regulation of Yersinia Pathophysiology. Front Cell Infect Microbiol 2016; 6:25. [PMID: 26973818 PMCID: PMC4773443 DOI: 10.3389/fcimb.2016.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/15/2016] [Indexed: 12/26/2022] Open
Abstract
Hallmarks of Yersinia pathogenesis include the ability to form biofilms on surfaces, the ability to establish close contact with eukaryotic target cells and the ability to hijack eukaryotic cell signaling and take over control of strategic cellular processes. Many of these virulence traits are already well-described. However, of equal importance is knowledge of both confined and global regulatory networks that collaborate together to dictate spatial and temporal control of virulence gene expression. This review has the purpose to incorporate historical observations with new discoveries to provide molecular insight into how some of these regulatory mechanisms respond rapidly to environmental flux to govern tight control of virulence gene expression by pathogenic Yersinia.
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Affiliation(s)
- Shiyun Chen
- Key Laboratory of Special Pathogens and Biosafety, Wuhan Institute of Virology, Chinese Academy of Sciences Wuhan, China
| | - Karl M Thompson
- Department of Microbiology, College of Medicine, Howard University Washington, DC, USA
| | - Matthew S Francis
- Umeå Centre for Microbial Research, Umeå UniversityUmeå, Sweden; Department of Molecular Biology, Umeå UniversityUmeå, Sweden
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