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McCarlie SJ, du Preez LL, Hernandez JC, Boucher CE, Bragg RR. Transcriptomic signature of bacteria exposed to benzalkonium chloride. Res Microbiol 2024; 175:104151. [PMID: 37952705 DOI: 10.1016/j.resmic.2023.104151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 10/30/2023] [Accepted: 11/01/2023] [Indexed: 11/14/2023]
Abstract
The COVID-19 pandemic has highlighted our reliance on biocides, the increasing prevalence of resistance to biocides is a risk to public health. Bacterial exposure to the biocide, benzalkonium chloride (BAC), resulted in a unique transcriptomic profile, characterised by both a short and long-term response. Differential gene expression was observed in four main areas: motility, membrane composition, proteostasis, and the stress response. A metabolism shift to protect the proteome and the stress response were prioritised suggesting these are main resistance mechanisms. Whereas "well-established" mechanisms, such as biofilm formation, were not found to be differentially expressed after exposure to BAC.
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Affiliation(s)
- Samantha J McCarlie
- Department of Microbiology and Biochemistry, University of the Free State, South Africa
| | - Louis L du Preez
- Research & HPC: ICT Services, University of the Free State, South Africa
| | | | - Charlotte E Boucher
- Department of Microbiology and Biochemistry, University of the Free State, South Africa
| | - Robert R Bragg
- Department of Microbiology and Biochemistry, University of the Free State, South Africa.
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2
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Transcriptomic and Proteomic Analysis of Gardnerella vaginalis Responding to Acidic pH and Hydrogen Peroxide Stress. Microorganisms 2023; 11:microorganisms11030695. [PMID: 36985268 PMCID: PMC10051395 DOI: 10.3390/microorganisms11030695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/07/2023] [Accepted: 03/07/2023] [Indexed: 03/11/2023] Open
Abstract
Gardnerella vaginalis is the main pathogen that causes bacterial vaginosis. In the healthy vaginal microecological environment of a woman, the lactobacilli produce lactate and hydrogen peroxide to inhibit the growth of pathogens such as G. vaginalis. The lack of lactobacilli results in a high pH and low hydrogen peroxide in the vagina which facilitate G. vaginalis growth, leading to the imbalance of the vaginal microecology. In this study, lactate and hydrogen peroxide were added to a G. vaginalis culture medium to simulate the co-culture of the lactobacilli and G. vaginalis, and then the genes related to the stress response of G. vaginalis were identified using transcriptomics and proteomics. It was indicated that, among all the upregulated genes, most of them encoded transporters associated with the efflux of harmful substances, and the majority of the downregulated genes were related to the biofilm formation and epithelial cell adhesion. This study may help find new drug targets for G. vaginalis for the development of novel therapies for bacterial vaginosis.
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The Molecular Basis of Acinetobacter baumannii Cadmium Toxicity and Resistance. Appl Environ Microbiol 2021; 87:e0171821. [PMID: 34495707 DOI: 10.1128/aem.01718-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Acinetobacter species are ubiquitous Gram-negative bacteria that can be found in water, in soil, and as commensals of the human skin. The successful inhabitation of Acinetobacter species in diverse environments is primarily attributable to the expression of an arsenal of stress resistance determinants, which includes an extensive repertoire of metal ion efflux systems. Metal ion homeostasis in the hospital pathogen Acinetobacter baumannii contributes to pathogenesis; however, insights into its metal ion transporters for environmental persistence are lacking. Here, we studied the impact of cadmium stress on A. baumannii. Our functional genomics and independent mutant analyses revealed a primary role for CzcE, a member of the cation diffusion facilitator (CDF) superfamily, in resisting cadmium stress. We also show that the CzcCBA heavy metal efflux system contributes to cadmium efflux. Collectively, these systems provide A. baumannii with a comprehensive cadmium translocation pathway from the cytoplasm to the periplasm and subsequently the extracellular space. Furthermore, analysis of the A. baumannii metallome under cadmium stress showed zinc depletion, as well as copper enrichment, both of which are likely to influence cellular fitness. Overall, this work provides new knowledge on the role of a broad arsenal of membrane transporters in A. baumannii metal ion homeostasis. IMPORTANCE Cadmium toxicity is a widespread problem, yet the interaction of this heavy metal with biological systems is poorly understood. Some microbes have evolved traits to proactively counteract cadmium toxicity, including Acinetobacter baumannii, which is notorious for persisting in harsh environments. Here, we show that A. baumannii utilizes a dedicated cadmium efflux protein in concert with a system that is primarily attuned to zinc efflux to efficiently overcome cadmium stress. The molecular characterization of A. baumannii under cadmium stress revealed how active cadmium efflux plays a key role in preventing the dysregulation of bacterial metal ion homeostasis, which appeared to be a primary means by which cadmium exerts toxicity upon the bacterium.
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Protective Role of Bacterial Alkanesulfonate Monooxygenase under Oxidative Stress. Appl Environ Microbiol 2020; 86:AEM.00692-20. [PMID: 32503904 DOI: 10.1128/aem.00692-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 05/26/2020] [Indexed: 01/05/2023] Open
Abstract
Bacterial alkane metabolism is associated with a number of cellular stresses, including membrane stress and oxidative stress, and the limited uptake of charged ions such as sulfate. In the present study, the genes ssuD and tauD in Acinetobacter oleivorans DR1 cells, which encode an alkanesulfonate monooxygenase and a taurine dioxygenase, respectively, were found to be responsible for hexadecanesulfonate (C16SO3H) and taurine metabolism, and Cbl was experimentally identified as a potential regulator of ssuD and tauD expression. The expression of ssuD and tauD occurred under sulfate-limited conditions generated during n-hexadecane degradation. Interestingly, expression analysis and knockout experiments suggested that both genes are required to protect cells against oxidative stress, including that generated by n-hexadecane degradation and H2O2 exposure. Measurable levels of intracellular hexadecanesulfonate were also produced during n-hexadecane degradation. Phylogenetic analysis suggested that ssuD and tauD are mainly present in soil-dwelling aerobes within the Betaproteobacteria and Gammaproteobacteria classes, which suggests that they function as controllers of the sulfur cycle and play a protective role against oxidative stress in sulfur-limited conditions.IMPORTANCE ssuD and tauD, which play a role in the degradation of organosulfonate, were expressed during n-hexadecane metabolism and oxidative stress conditions in A. oleivorans DR1. Our study confirmed that hexadecanesulfonate was accidentally generated during bacterial n-hexadecane degradation in sulfate-limited conditions. Removal of this by-product by SsuD and TauD must be necessary for bacterial survival under oxidative stress generated during n-hexadecane degradation.
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Shin B, Park C, Park W. Stress responses linked to antimicrobial resistance in Acinetobacter species. Appl Microbiol Biotechnol 2020; 104:1423-1435. [DOI: 10.1007/s00253-019-10317-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 12/09/2019] [Accepted: 12/13/2019] [Indexed: 11/25/2022]
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Shin B, Park C, Park W. OxyR-controlled surface polysaccharide production and biofilm formation in Acinetobacter oleivorans DR1. Appl Microbiol Biotechnol 2019; 104:1259-1271. [PMID: 31863146 DOI: 10.1007/s00253-019-10303-5] [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: 07/25/2019] [Revised: 11/27/2019] [Accepted: 12/08/2019] [Indexed: 11/24/2022]
Abstract
The genomes of several Acinetobacter species possess three distinct polysaccharide-producing operons [two poly-N-acetyl glucosamine (PNAG) and one K-locus]. Using a microfluidic device, an increased amount of polysaccharides and enhanced biofilm formation were observed following continuous exposure to H2O2 and removal of the H2O2-sensing key regulator, OxyR, in Acinetobacter oleivorans DR1 cells. Gene expression analysis revealed that genes located in PNAG1, but not those in PNAG2, were induced and that genes in the K-locus were expressed in the presence of H2O2. Interestingly, the expression of the K-locus gene was enhanced in the PNAG1 mutant and vice versa. The absence of either OxyR or PNAG1 resulted in enhanced biofilm formation, higher surface hydrophobicity, and increased motility, implying that K-locus-driven polysaccharide production in both the oxyR and PNAG1 deletion mutants may be related to these phenotypes. Both the oxyR and K-locus deletion mutants were more sensitive to H2O2 compared with the wildtype and PNAG1 mutant strains. Purified OxyR binds to the promoter regions of both polysaccharide operons with a higher affinity toward the K-locus promoter. Although oxidized OxyR could bind to both promoter regions, the addition of dithiothreitol further enhanced the binding efficiency of OxyR, suggesting that OxyR might function as a repressor for controlling these polysaccharide operons.
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Affiliation(s)
- Bora Shin
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Chulwoo Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea
| | - Woojun Park
- Laboratory of Molecular Environmental Microbiology, Department of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.
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7
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Lipus D, Vikram A, Gulliver D, Bibby K. Upregulation of peroxide scavenging enzymes and multidrug efflux proteins highlight an active sodium hypochlorite response in Pseudomonas fluorescens biofilms. BIOFOULING 2019; 35:329-339. [PMID: 31066290 DOI: 10.1080/08927014.2019.1605357] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
The oxidative biocide sodium hypochlorite is among the most commonly used antimicrobial agents in the control of surface-attached microbial communities (biofilms). Clarifying the genetic response of microorganisms in biofilms to hypochlorite may contribute to improved biofilm control strategies. Here, RNA-seq was used to investigate the differential gene expression response of industrially relevant Pseudomonas fluorescens biofilms to sub-lethal concentrations of sodium hypochlorite. Pseudomonas biofilms responded to hypochlorite exposure with increased transcription of genes encoding peroxide scavenging enzymes (e.g., alkyl hydroperoxide reductase (Ahp) and hydroperoxide resistance protein (Ohr)), oxidative stress repair enzymes (e.g., the periplasmic sulfoxide reductase YedYZ complex), and multidrug efflux (e.g., MexEF pumps). In addition, genes involved in amino acid synthesis and energy metabolism were down-regulated following hypochlorite exposure. This work improves the current understanding of genetic response mechanisms to biocides and contributes to the optimization of biocides and application strategies.
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Affiliation(s)
- Daniel Lipus
- a National Energy Technology Laboratory (NETL) , Pittsburgh , Pennsylvania , USA
- b Oak Ridge Institute for Science and Education , Oak Ridge , Tennessee , USA
- c Department of Civil and Environmental Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania , USA
| | - Amit Vikram
- d US Department of Agriculture , Agricultural Research Service, Roman L. Hruska US Meat Animal Research Center, Clay Center , Nebraska
| | - Djuna Gulliver
- a National Energy Technology Laboratory (NETL) , Pittsburgh , Pennsylvania , USA
| | - Kyle Bibby
- b Oak Ridge Institute for Science and Education , Oak Ridge , Tennessee , USA
- c Department of Civil and Environmental Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania , USA
- e Department of Civil & Environmental Engineering & Earth Sciences , University of Notre Dame , South Bend , Indiana , USA
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8
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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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Mechanism of antagonistic effects of Andrographis paniculata methanolic extract against Staphylococcus aureus. ASIAN PAC J TROP MED 2017; 10:685-695. [DOI: 10.1016/j.apjtm.2017.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 05/17/2017] [Accepted: 06/23/2017] [Indexed: 11/19/2022] Open
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10
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Solyanikova IP, Suzina NE, Emelyanova EV, Polivtseva VN, Pshenichnikova AB, Lobanok AG, Golovleva LA. Morphological, physiological, and biochemical characteristics of a benzoate-degrading strain Rhodococcus opacus 1CP under stress conditions. Microbiology (Reading) 2017. [DOI: 10.1134/s0026261717020199] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
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11
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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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12
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Liu W, Golshan NH, Deng X, Hickey DJ, Zeimer K, Li H, Webster TJ. Selenium nanoparticles incorporated into titania nanotubes inhibit bacterial growth and macrophage proliferation. NANOSCALE 2016; 8:15783-15794. [PMID: 27533297 DOI: 10.1039/c6nr04461a] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Since implants often fail due to infection and uncontrolled inflammatory responses, we designed an in vitro study to investigate the antibacterial and anti-inflammatory properties of titanium dioxide nanotubes (TNTs) incorporated with selenium nanoparticles (SeNPs). Selenium incorporation was achieved by the reaction of sodium selenite (Na2SeO3) with glutathione (GSH) under a vacuum in the presence of TNTs. Two types of bacteria and macrophages were cultured on the samples to determine their respective antibacterial and anti-inflammatory properties. The results showed that the TNT samples incorporating SeNPs (TNT-Se) inhibited the growth of Escherichia coli and Staphylococcus aureus compared to unmodified TNTs, albeit the SeNP concentration still needs to be optimized for maximal effect. At their maximum effect, the TNT-Se samples reduced the density of E. coli by 94.6% and of S. aureus by 89.6% compared to titanium controls. To investigate the underlying mechanism of this effect, the expression of six E. coli genes were tracked using qRT-PCR. Results indicated that SeNPs weakened E. coli membranes (ompA and ompF were down-regulated), decreased the function of adhesion-mediating proteins (csgA and csgG were progressively down-regulated with increasing SeNP content), and induced the production of damaging reactive oxygen species (ahpF was up-regulated). Moreover, TNT-Se samples inhibited the proliferation of macrophages, indicating that they can be used to control the inflammatory response and even prevent chronic inflammation, a condition that often leads to implant failure. In conclusion, we demonstrated that SeNP-TNTs display antibacterial and anti-inflammatory properties that are promising for improving the performance of titanium-based implants for numerous orthopedic and dental applications.
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Affiliation(s)
- Wenwen Liu
- Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, PR China. and Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
| | - Negar H Golshan
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
| | - Xuliang Deng
- Department of Geriatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, PR China.
| | - Daniel J Hickey
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
| | - Katherine Zeimer
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA.
| | - Hongyi Li
- Photoelectrochemical Research Group, Key Laboratory of Advanced Functional Materials, School of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
| | - Thomas J Webster
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA. and Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia
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Peralta DR, Adler C, Corbalán NS, Paz García EC, Pomares MF, Vincent PA. Enterobactin as Part of the Oxidative Stress Response Repertoire. PLoS One 2016; 11:e0157799. [PMID: 27310257 PMCID: PMC4911079 DOI: 10.1371/journal.pone.0157799] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 06/03/2016] [Indexed: 12/28/2022] Open
Abstract
Microorganisms produce siderophores to facilitate iron uptake and even though this trait has been extensively studied, there is growing evidence suggesting that siderophores may have other physiological roles aside from iron acquisition. In support of this notion, we previously linked the archetypal siderophore enterobactin with oxidative stress alleviation. To further characterize this association, we studied the sensitivity of Escherichia coli strains lacking different components of the enterobactin system to the classical oxidative stressors hydrogen peroxide and paraquat. We observed that strains impaired in enterobactin production, uptake and hydrolysis were more susceptible to the oxidative damage caused by both compounds than the wild-type strain. In addition, meanwhile iron supplementation had little impact on the sensitivity, the reducing agent ascorbic acid alleviated the oxidative stress and therefore significantly decreased the sensitivity to the stressors. This indicated that the enterobactin-mediated protection is independent of its ability to scavenge iron. Furthermore, enterobactin supplementation conferred resistance to the entE mutant but did not have any protective effect on the fepG and fes mutants. Thus, we inferred that only after enterobactin is hydrolysed by Fes in the cell cytoplasm and iron is released, the free hydroxyl groups are available for radical stabilization. This hypothesis was validated testing the ability of enterobactin to scavenge radicals in vitro. Given the strong connection between enterobactin and oxidative stress, we studied the transcription of the entE gene and the concomitant production of the siderophore in response to such kind of stress. Interestingly, we observed that meanwhile iron represses the expression and production of the siderophore, hydrogen peroxide and paraquat favour these events even if iron is present. Our results support the involvement of enterobactin as part of the oxidative stress response and highlight the existence of a novel regulation mechanism for enterobactin biosynthesis.
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Affiliation(s)
- Daiana R. Peralta
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica “Dr. Bernabé Bloj”, Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI -San Miguel de Tucumán, Tucumán, Argentina
| | - Conrado Adler
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica “Dr. Bernabé Bloj”, Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI -San Miguel de Tucumán, Tucumán, Argentina
| | - Natalia S. Corbalán
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica “Dr. Bernabé Bloj”, Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI -San Miguel de Tucumán, Tucumán, Argentina
| | - Enrique Carlos Paz García
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica “Dr. Bernabé Bloj”, Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI -San Miguel de Tucumán, Tucumán, Argentina
| | - María Fernanda Pomares
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica “Dr. Bernabé Bloj”, Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI -San Miguel de Tucumán, Tucumán, Argentina
| | - Paula A. Vincent
- Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT and Instituto de Química Biológica “Dr. Bernabé Bloj”, Facultad de Bioquímica, Química y Farmacia, UNT. Chacabuco 461, T4000ILI -San Miguel de Tucumán, Tucumán, Argentina
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14
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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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15
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Endogenous hydrogen peroxide increases biofilm formation by inducing exopolysaccharide production in Acinetobacter oleivorans DR1. Sci Rep 2016; 6:21121. [PMID: 26884212 PMCID: PMC4756669 DOI: 10.1038/srep21121] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 01/05/2016] [Indexed: 12/15/2022] Open
Abstract
In this study, we investigated differentially expressed proteins in Acinetobacter oleivorans cells during planktonic and biofilm growth by using 2-dimensional gel electrophoresis combined with matrix-assisted laser desorption time-of-flight mass spectrometry. We focused on the role of oxidative stress resistance during biofilm formation using mutants defective in alkyl hydroperoxide reductase (AhpC) because its production in aged biofilms was enhanced compared to that in planktonic cells. Results obtained using an ahpC promoter-gfp reporter vector showed that aged biofilms expressed higher ahpC levels than planktonic cells at 48 h. However, at 24 h, ahpC expression was higher in planktonic cells than in biofilms. Deletion of ahpC led to a severe growth defect in rich media that was not observed in minimal media and promoted early biofilm formation through increased production of exopolysaccharide (EPS) and EPS gene expression. Increased endogenous H2O2 production in the ahpC mutant in rich media enhanced biofilm formation, and this enhancement was not observed in the presence of antioxidants. Exogenous addition of H2O2 promoted biofilm formation in wild type cells, which suggested that biofilm development is linked to defense against H2O2. Collectively, our data showed that EPS production caused by H2O2 stress enhances biofilm formation in A. oleivorans.
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