1
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He H, Shi M, Yang X, Zhan J, Lin Y, Guo Z, Liao Z, Lai C, Ren X, Huang B, Pan X. Dissolved organic matter accelerates microbial degradation of 17 alpha-ethinylestradiol in the presence of iron mineral. J Environ Sci (China) 2024; 139:364-376. [PMID: 38105062 DOI: 10.1016/j.jes.2023.05.042] [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: 04/06/2023] [Revised: 05/30/2023] [Accepted: 05/30/2023] [Indexed: 12/19/2023]
Abstract
Dissolved organic matter (DOM) and iron minerals widely existing in the natural aquatic environment can mediate the migration and transformation of organic pollutants. However, the mechanism of interaction between DOM and iron minerals in the microbial degradation of pollutants deserves further investigation. In this study, the mechanism of 17 alpha-ethinylestradiol (EE2) biodegradation mediated by humic acid (HA) and three kinds of iron minerals (goethite, magnetite, and pyrite) was investigated. The results found that HA and iron minerals significantly accelerated the biodegradation process of EE2, and the highest degradation efficiency of EE2 (48%) was observed in the HA-mediated microbial system with pyrite under aerobic conditions. Furthermore, it had been demonstrated that hydroxyl radicals (HO•) was the main active substance responsible for the microbial degradation of EE2. HO• is primarily generated through the reaction between hydrogen peroxide secreted by microorganisms and Fe(II), with aerobic conditions being more conducive. The presence of iron minerals and HA could change the microbial communities in the EE2 biodegradation system. These findings provide new information for exploring the migration and transformation of pollutants by microorganisms in iron-rich environments.
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Affiliation(s)
- Huan He
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Min Shi
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Xiaoxia Yang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Juhong Zhan
- Research Institute for Environmental Innovation (Suzhou) Tsinghua, Suzhou 215163, China.
| | - Yanting Lin
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Ziwei Guo
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Zhicheng Liao
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Chaochao Lai
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Xiaomin Ren
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China
| | - Bin Huang
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Kunming 650500, China.
| | - Xuejun Pan
- Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, China; Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control, Kunming 650500, China
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2
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Zhou H, Zhang Y, Long CP, Xia X, Xue Y, Ma Y, Antoniewicz MR, Tao Y, Lin B. A citric acid cycle-deficient Escherichia coli as an efficient chassis for aerobic fermentations. Nat Commun 2024; 15:2372. [PMID: 38491007 PMCID: PMC10943122 DOI: 10.1038/s41467-024-46655-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 03/05/2024] [Indexed: 03/18/2024] Open
Abstract
Tricarboxylic acid cycle (TCA cycle) plays an important role for aerobic growth of heterotrophic bacteria. Theoretically, eliminating TCA cycle would decrease carbon dissipation and facilitate chemicals biosynthesis. Here, we construct an E. coli strain without a functional TCA cycle that can serve as a versatile chassis for chemicals biosynthesis. We first use adaptive laboratory evolution to recover aerobic growth in minimal medium of TCA cycle-deficient E. coli. Inactivation of succinate dehydrogenase is a key event in the evolutionary trajectory. Supply of succinyl-CoA is identified as the growth limiting factor. By replacing endogenous succinyl-CoA dependent enzymes, we obtain an optimized TCA cycle-deficient E. coli strain. As a proof of concept, the strain is engineered for high-yield production of four separate products. This work enhances our understanding of the role of the TCA cycle in E. coli metabolism and demonstrates the advantages of using TCA cycle-deficient E. coli strain for biotechnological applications.
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Affiliation(s)
- Hang Zhou
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yiwen Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Christopher P Long
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE, 19716, USA
| | - Xuesen Xia
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Yanfen Xue
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yanhe Ma
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China.
| | - Maciek R Antoniewicz
- Department of Chemical and Biomolecular Engineering, Metabolic Engineering and Systems Biology Laboratory, University of Delaware, Newark, DE, 19716, USA.
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA.
| | - Yong Tao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China.
- University of Chinese Academy of Sciences, 100049, Beijing, China.
| | - Baixue Lin
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, China.
- University of Chinese Academy of Sciences, 100049, Beijing, China.
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3
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Webster CM, Shepherd M. The nitric oxide paradox: antimicrobial and inhibitor of antibiotic efficacy. Emerg Top Life Sci 2024; 8:37-43. [PMID: 37975610 PMCID: PMC10903473 DOI: 10.1042/etls20230114] [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: 09/15/2023] [Revised: 11/09/2023] [Accepted: 11/10/2023] [Indexed: 11/19/2023]
Abstract
It is well-known that antibiotics target energy-consuming processes and a significant body of research now supports the conclusion that the metabolic state of bacteria can have a profound impact upon the efficacy of antibiotics. Several articles implicate bacterial energetics and the respiratory inhibitor nitric oxide (NO) in this process, although pinpointing the precise mechanism for how NO can diminish the potency of a range of antibiotics through modulating bacterial energy metabolism has proved challenging. Herein, we introduce the role of NO during infection, consider known links between NO and antibiotic efficacy, and discuss potential mechanisms via which NO present at the site of infection could mediate these effects through controlling bacterial energetics. This perspective article highlights an important relationship between NO and antibiotic action that has largely been overlooked and outlines future considerations for the development of new drugs and therapies that target bacterial energy metabolism.
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Affiliation(s)
- Calum M Webster
- School of Biosciences, RAPID Group, University of Kent, Canterbury CT2 7NJ, U.K
| | - Mark Shepherd
- School of Biosciences, RAPID Group, University of Kent, Canterbury CT2 7NJ, U.K
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4
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Tikhomirova A, Rahman MM, Kidd SP, Ferrero RL, Roujeinikova A. Cysteine and resistance to oxidative stress: implications for virulence and antibiotic resistance. Trends Microbiol 2024; 32:93-104. [PMID: 37479622 DOI: 10.1016/j.tim.2023.06.010] [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: 05/18/2023] [Revised: 06/28/2023] [Accepted: 06/30/2023] [Indexed: 07/23/2023]
Abstract
Reactive oxygen species (ROS), including the superoxide radical anion (O2•-), hydrogen peroxide (H2O2), and the hydroxyl radical (•HO), are inherent components of bacterial metabolism in an aerobic environment. Bacteria also encounter exogenous ROS, such as those produced by the host cells during the respiratory burst. As ROS have the capacity to damage bacterial DNA, proteins, and lipids, detoxification of ROS is critical for bacterial survival. It has been recently recognised that low-molecular-weight (LMW) thiols play a central role in this process. Here, we review the emerging role of cysteine in bacterial resistance to ROS with a link to broader elements of bacterial lifestyle closely associated with cysteine-mediated oxidative stress response, including virulence and antibiotic resistance.
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Affiliation(s)
- Alexandra Tikhomirova
- Monash University, Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia
| | - Mohammad M Rahman
- University of Kentucky, Department of Microbiology, Immunology and Molecular Genetics, Lexington, KY, USA
| | - Stephen P Kidd
- University of Adelaide, Department of Molecular and Biomedical Sciences, School of Biological Sciences, Adelaide, SA 5005, Australia; University of Adelaide, Research Centre for Infectious Disease (RCID) and Australian Centre for Antimicrobial Resistance Ecology (ACARE), Adelaide, SA 5005, Australia
| | - Richard L Ferrero
- Monash University, Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia; Hudson Institute of Medical Research, Centre for Innate Immunity and Infectious Diseases, Melbourne, VIC 3168, Australia; Monash University, Department of Molecular and Translational Science, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia
| | - Anna Roujeinikova
- Monash University, Department of Microbiology, Infection and Immunity Program, Monash Biomedicine Discovery Institute, Melbourne, VIC 3800, Australia; Monash University, Department of Biochemistry and Molecular Biology, Melbourne, VIC 3800, Australia.
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5
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Zhang F, O’Brian MR. The divalent metal ion exporter IhpABC is required to maintain iron homeostasis under low to moderate environmental iron conditions in the bacterium Bradyrhizobium japonicum. Mol Microbiol 2024; 121:85-97. [PMID: 38038163 PMCID: PMC10841971 DOI: 10.1111/mmi.15198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/06/2023] [Accepted: 11/13/2023] [Indexed: 12/02/2023]
Abstract
Bacterial iron export mitigates high iron stress, but a role for it under lower iron conditions has not been established. MbfA is the high iron stress exporter in Bradyrhizobium japonicum. Here, we identify the ihpABC genes in a selection for secondary site mutations that suppress the poor growth phenotype of feoAB mutants defective in iron acquisition. IhpABC belongs to the RND tripartite efflux pump family. High iron conditions that derepress the mbfA gene partially rescued the growth of an ihpC mutant but reverted the feoB ihpC mutant to the feoB growth phenotype. The ihpA mutant grown under low iron conditions accumulated higher levels of iron compared to the wild type, and it displayed aberrant iron-responsive gene expression. The mbfA mutant was more sensitive than the wild type to H2 O2 , but the ihpA mutant was not sensitive. The ihpA mutant accumulated more Zn, Co and Cd than was found in the wild type, and growth of the mutant was more sensitive to inhibition by ZnCl2 , CoCl2 and CdCl2 . The findings suggest that IhpABC is a divalent metal ion exporter that helps maintain iron homeostasis under low to moderate environmental iron levels. Thus, iron export is not limited to managing high iron stress.
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Affiliation(s)
- Fengyue Zhang
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, The University at Buffalo, 955 Main Street, Suite 4102, Buffalo, New York 14203 USA
| | - Mark R. O’Brian
- Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, The University at Buffalo, 955 Main Street, Suite 4102, Buffalo, New York 14203 USA
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6
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Bruna RE, Kendra CG, Pontes MH. Phosphorus starvation response and PhoB-independent utilization of organic phosphate sources by Salmonella enterica. Microbiol Spectr 2023; 11:e0226023. [PMID: 37787565 PMCID: PMC10715179 DOI: 10.1128/spectrum.02260-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 08/21/2023] [Indexed: 10/04/2023] Open
Abstract
IMPORTANCE Phosphorus (P) is the fifth most abundant element in living cells. This element is acquired mainly as inorganic phosphate (Pi, PO4 3-). In enteric bacteria, P starvation activates a two-component signal transduction system which is composed of the membrane sensor protein PhoR and its cognate transcription regulator PhoB. PhoB, in turn, promotes the transcription of genes that help maintain Pi homeostasis. Here, we characterize the P starvation response of the bacterium Salmonella enterica. We determine the PhoB-dependent and independent transcriptional changes promoted by P starvation and identify proteins enabling the utilization of a range of organic substrates as sole P sources. We show that transcription and activity of a subset of these proteins are independent of PhoB and Pi availability. These results establish that Salmonella enterica can maintain Pi homeostasis and repress PhoB/PhoR activation even when cells are grown in medium lacking Pi.
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Affiliation(s)
- Roberto E. Bruna
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Christopher G. Kendra
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Mauricio H. Pontes
- Department of Pathology and Laboratory Medicine, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
- The One Health Microbiome Center, Huck Institute of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
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7
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Eng T, Banerjee D, Menasalvas J, Chen Y, Gin J, Choudhary H, Baidoo E, Chen JH, Ekman A, Kakumanu R, Diercks YL, Codik A, Larabell C, Gladden J, Simmons BA, Keasling JD, Petzold CJ, Mukhopadhyay A. Maximizing microbial bioproduction from sustainable carbon sources using iterative systems engineering. Cell Rep 2023; 42:113087. [PMID: 37665664 DOI: 10.1016/j.celrep.2023.113087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 07/10/2023] [Accepted: 08/18/2023] [Indexed: 09/06/2023] Open
Abstract
Maximizing the production of heterologous biomolecules is a complex problem that can be addressed with a systems-level understanding of cellular metabolism and regulation. Specifically, growth-coupling approaches can increase product titers and yields and also enhance production rates. However, implementing these methods for non-canonical carbon streams is challenging due to gaps in metabolic models. Over four design-build-test-learn cycles, we rewire Pseudomonas putida KT2440 for growth-coupled production of indigoidine from para-coumarate. We explore 4,114 potential growth-coupling solutions and refine one design through laboratory evolution and ensemble data-driven methods. The final growth-coupled strain produces 7.3 g/L indigoidine at 77% maximum theoretical yield in para-coumarate minimal medium. The iterative use of growth-coupling designs and functional genomics with experimental validation was highly effective and agnostic to specific hosts, carbon streams, and final products and thus generalizable across many systems.
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Affiliation(s)
- Thomas Eng
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Deepanwita Banerjee
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Javier Menasalvas
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yan Chen
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jennifer Gin
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Hemant Choudhary
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biomanufacturing and Biomaterials Department, Sandia National Laboratories, Livermore, CA, USA
| | - Edward Baidoo
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jian Hua Chen
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA; National Center for X-ray Tomography, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Axel Ekman
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA; National Center for X-ray Tomography, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Ramu Kakumanu
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Yuzhong Liu Diercks
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Alex Codik
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Carolyn Larabell
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA; National Center for X-ray Tomography, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - John Gladden
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biomanufacturing and Biomaterials Department, Sandia National Laboratories, Livermore, CA, USA
| | - Blake A Simmons
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Jay D Keasling
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; QB3 Institute, University of California, Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, USA; Department of Chemical & Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA; Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University Denmark, 2970 Horsholm, Denmark; Synthetic Biochemistry Center, Institute for Synthetic Biology, Shenzhen Institutes for Advanced Technologies, Shenzhen, China
| | - Christopher J Petzold
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Aindrila Mukhopadhyay
- The Joint BioEnergy Institute, Lawrence Berkeley National Laboratory, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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8
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Gao Y, Chen Z, Nakanishi H, Li Z. Highly Efficient Synthesis of Rare Sugars from Glycerol in Endotoxin-Free ClearColi by Fermentation. Foods 2023; 12:3078. [PMID: 37628077 PMCID: PMC10453619 DOI: 10.3390/foods12163078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/13/2023] [Accepted: 08/15/2023] [Indexed: 08/27/2023] Open
Abstract
Rare sugars possess potential applications as low-calorie sweeteners, especially for anti-obesity and anti-diabetes. In this study, a fermentation biosystem based on the "DHAP-dependent aldolases strategy" was established for D-allulose and D-sorbose production from glycerol in endotoxin-free ClearColi BL21 (DE3). Several engineering strategies were adopted to enhance rare sugar production. Firstly, the combination of different plasmids for aldO, rhaD, and yqaB expression was optimized. Then, the artificially constructed ribosomal binding site (RBS) libraries of aldO, rhaD, and yqaB genes were assembled individually and combinatorially. In addition, a peroxidase was overexpressed to eliminate the damage or toxicity from hydrogen peroxide generated by alditol oxidase (AldO). Finally, stepwise improvements in rare sugar synthesis were elevated to 15.01 g/L with a high yield of 0.75 g/g glycerol in a 3 L fermenter. This research enables the effective production of rare sugars from raw glycerol in high yields.
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Affiliation(s)
- Yahui Gao
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Zhou Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zijie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China
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9
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He Y, Pan J, Huang D, Sanford RA, Peng S, Wei N, Sun W, Shi L, Jiang Z, Jiang Y, Hu Y, Li S, Li Y, Li M, Dong Y. Distinct microbial structure and metabolic potential shaped by significant environmental gradient impacted by ferrous slag weathering. ENVIRONMENT INTERNATIONAL 2023; 178:108067. [PMID: 37393724 DOI: 10.1016/j.envint.2023.108067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/04/2023]
Abstract
Alkaline ferrous slags pose global environmental issues and long-term risks to ambient environments. To explore the under-investigated microbial structure and biogeochemistry in such unique ecosystems, combined geochemical, microbial, ecological and metagenomic analyses were performed in the areas adjacent to a ferrous slag disposal plant in Sichuan, China. Different levels of exposure to ultrabasic slag leachate had resulted in a significant geochemical gradient of pH (8.0-12.4), electric potential (-126.9 to 437.9 mV), total organic carbon (TOC, 1.5-17.3 mg/L), and total nitrogen (TN, 0.17-1.01 mg/L). Distinct microbial communities were observed depending on their exposure to the strongly alkaline leachate. High pH and Ca2+ concentrations were associated with low microbial diversity and enrichment of bacterial classes Gamma-proteobacteria and Deinococci in the microbial communities exposed to the leachate. Combined metagenomic analyses of 4 leachate-unimpacted and 2-impacted microbial communities led to the assembly of one Serpentinomonas pangenome and 81 phylogenetically diversified metagenome assembled genomes (MAGs). The prevailing taxa in the leachate-impacted habitats (e.g., Serpentinomonas and Meiothermus spp.) were phylogenetically related to those in active serpentinizing ecosystems, suggesting the analogous processes between the man-made and natural systems. More importantly, they accounted for significant abundance of most functional genes associated with environmental adaptation and major element cycling. Their metabolic potential (e.g., cation/H+ antiporters, carbon fixation on lithospheric carbon source, and respiration coupling sulfur oxidization and oxygen or nitrate reduction) may support these taxa to survive and prosper in these unique geochemical niches. This study provides fundamental understandings of the adaptive strategies of microorganisms in response to the strong environmental perturbation by alkali tailings. It also contributes to a better comprehension of how to remediate environments affected by alkaline industrial material.
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Affiliation(s)
- Yu He
- School of Environmental Studies, China University of Geosciences, China
| | - Jie Pan
- Archaeal Biology Center, Institute for Advanced Studies, Shenzhen University, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, China
| | - Dongmei Huang
- School of Environmental Studies, China University of Geosciences, China; Yejin Geological Team of Hubei Geological Bureau, China
| | - Robert A Sanford
- Department of Earth Science & Environmental Change, University of Illinois Urbana-Champaign, Champaign, IL, United States
| | - Shuming Peng
- Institute of Ecological Environment, Chengdu University of Technology, China
| | - Na Wei
- Department of Civil and Environmental Engineering, University of Illinois Urbana-Champaign, Champaign, IL, United States
| | - Weimin Sun
- Guangdong Institute of Eco-environmental and Soil Science, Guangdong, China
| | - Liang Shi
- School of Environmental Studies, China University of Geosciences, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China
| | - Zhou Jiang
- School of Environmental Studies, China University of Geosciences, China
| | - Yongguang Jiang
- School of Environmental Studies, China University of Geosciences, China
| | - Yidan Hu
- School of Environmental Studies, China University of Geosciences, China
| | - Shuyi Li
- School of Environmental Studies, China University of Geosciences, China
| | - Yongzhe Li
- School of Environmental Studies, China University of Geosciences, China
| | - Meng Li
- Archaeal Biology Center, Institute for Advanced Studies, Shenzhen University, China; Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, China.
| | - Yiran Dong
- School of Environmental Studies, China University of Geosciences, China; State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, China; State Environmental Protection Key Laboratory of Source Apportionment and Control of Aquatic Pollution, Ministry of Ecology and Environment, China; Hubei Key Laboratory of Yangtze Catchment Environmental Aquatic Science, China; Hubei Key Laboratory of Wetland Evolution and Ecology Restoration, China.
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10
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Hu M, Zhang Y, Huang X, He M, Zhu J, Zhang Z, Cui Y, He S, Shi X. PhoPQ Regulates Quinolone and Cephalosporin Resistance Formation in Salmonella Enteritidis at the Transcriptional Level. mBio 2023:e0339522. [PMID: 37184399 DOI: 10.1128/mbio.03395-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
The two-component system (TCS) PhoPQ has been demonstrated to be crucial for the formation of resistance to quinolones and cephalosporins in Salmonella Enteritidis (S. Enteritidis). However, the mechanism underlying PhoPQ-mediated antibiotic resistance formation remains poorly understood. Here, it was shown that PhoP transcriptionally regulated an assortment of genes associated with envelope homeostasis, the osmotic stress response, and the redox balance to confer resistance to quinolones and cephalosporins in S. Enteritidis. Specifically, cells lacking the PhoP regulator, under nalidixic acid and ceftazidime stress, bore a severely compromised membrane on the aspects of integrity, fluidity, and permeability, with deficiency to withstand osmolarity stress, an increased accumulation of intracellular reactive oxygen species, and dysregulated redox homeostasis, which are unfavorable for bacterial survival. The phosphorylated PhoP elicited transcriptional alterations of resistance-associated genes, including the outer membrane porin ompF and the aconitate hydratase acnA, by directly binding to their promoters, leading to a limited influx of antibiotics and a well-maintained intracellular metabolism. Importantly, it was demonstrated that the cavity of the PhoQ sensor domain bound to and sensed quinolones/cephalosporins via the crucial surrounding residues, as their mutations abrogated the binding and PhoQ autophosphorylation. This recognition mode promoted signal transduction that activated PhoP, thereby modulating the transcription of downstream genes to accommodate cells to antibiotic stress. These findings have revealed how bacteria employ a specific TCS to sense antibiotics and combat them, suggesting PhoPQ as a potential drug target with which to surmount S. Enteritidis. IMPORTANCE The prevalence of quinolone and cephalosporin-resistant S. Enteritidis is of increasing clinical concern. Thus, it is imperative to identify novel therapeutic targets with which to treat S. Enteritidis-associated infections. The PhoPQ two-component system is conserved across a variety of Gram-negative pathogens, by which bacteria adapt to a range of environmental stimuli. Our earlier work has demonstrated the importance of PhoPQ in the resistance formation in S. Enteritidis to quinolones and cephalosporins. In the current work, we identified a global profile of genes that are regulated by PhoP under antibiotic stresses, with a focus on how PhoP regulated downstream genes, either positively or negatively. Additionally, we established that PhoQ sensed quinolones and cephalosporins in a manner of directly binding to them. These identified genes and pathways that are mediated by PhoPQ represent promising targets for the development of a drug potentiator with which to neutralize antibiotic resistance in S. Enteritidis.
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Affiliation(s)
- Mengjun Hu
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Yuyan Zhang
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaozhen Huang
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Mu He
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Jinyu Zhu
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Zengfeng Zhang
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Cui
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Shoukui He
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xianming Shi
- Department of Food Science & Technology, School of Agriculture & Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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11
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Bruna RE, Kendra CG, Pontes MH. An intracellular phosphorus-starvation signal activates the PhoB/PhoR two-component system in Salmonella enterica. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.23.533958. [PMID: 36993483 PMCID: PMC10055408 DOI: 10.1101/2023.03.23.533958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Bacteria acquire P primarily as inorganic orthophosphate (Pi, PO43-). Once internalized, Pi is rapidly assimilated into biomass during the synthesis of ATP. Because Pi is essential, but excessive ATP is toxic, the acquisition of environmental Pi is tightly regulated. In the bacterium Salmonella enterica (Salmonella), growth in Pi-limiting environments activates the membrane sensor histidine kinase PhoR, leading to the phosphorylation of its cognate transcriptional regulator PhoB and subsequent transcription of genes involved in adaptations to low Pi. Pi limitation is thought to promote PhoR kinase activity by altering the conformation of a membrane signaling complex comprised by PhoR, the multicomponent Pi transporter system PstSACB and the regulatory protein PhoU. However, the identity of the low Pi signal and how it controls PhoR activity remain unknown. Here we characterize the PhoB-dependent and independent transcriptional changes elicited by Salmonella in response to P starvation, and identify PhoB-independent genes that are required for the utilization of several organic-P sources. We use this knowledge to identify the cellular compartment where the PhoR signaling complex senses the Pi-limiting signal. We demonstrate that the PhoB and PhoR signal transduction proteins can be maintained in an inactive state even when Salmonella is grown in media lacking Pi. Our results establish that PhoR activity is controlled by an intracellular signal resulting from P insufficiency.
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Affiliation(s)
- Roberto E. Bruna
- Department of Pathology and Laboratory Medicine, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
| | - Christopher G. Kendra
- Department of Pathology and Laboratory Medicine, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
| | - Mauricio H. Pontes
- Department of Pathology and Laboratory Medicine, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
- Department of Microbiology and Immunology, Pennsylvania State College of Medicine, Hershey, PA 17033, United States of America
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12
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Moreau PL. Regulation of phosphate starvation-specific responses in Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36972330 DOI: 10.1099/mic.0.001312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Toxic agents added into the medium of rapidly growing Escherichia coli induce specific stress responses through the activation of specialized transcription factors. Each transcription factor and downstream regulon (e.g. SoxR) are linked to a unique stress (e.g. superoxide stress). Cells starved of phosphate induce several specific stress regulons during the transition to stationary phase when the growth rate is steadily declining. Whereas the regulatory cascades leading to the expression of specific stress regulons are well known in rapidly growing cells stressed by toxic products, they are poorly understood in cells starved of phosphate. The intent of this review is to both describe the unique mechanisms of activation of specialized transcription factors and discuss signalling cascades leading to the induction of specific stress regulons in phosphate-starved cells. Finally, I discuss unique defence mechanisms that could be induced in cells starved of ammonium and glucose.
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Affiliation(s)
- Patrice L Moreau
- Laboratoire Chimie Bactérienne, LCB-UMR 7283, Institut Microbiologie Méditerranée, CNRS/Université Aix-Marseille, Marseille, France
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13
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Marcos-Fernández R, Blanco-Míguez A, Ruiz L, Margolles A, Ruas-Madiedo P, Sánchez B. Towards the isolation of more robust next generation probiotics: The first aerotolerant Bifidobacterium bifidum strain. Food Res Int 2023; 165:112481. [PMID: 36869494 DOI: 10.1016/j.foodres.2023.112481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 11/20/2022] [Accepted: 01/11/2023] [Indexed: 01/19/2023]
Abstract
This work reports on the first described aerotolerant Bifidobacterium bifidum strain, Bifidobacterium bifidum IPLA60003, which has the ability to form colonies on the surface of agar plates under aerobic conditions, a weird phenotype that to our knowledge has never been observed in B. bifidum. The strain IPLA60003 was generated after random UV mutagenesis from an intestinal isolate. It incorporates 26 single nucleotide polymorphisms that activate the expression of native oxidative-defense mechanisms such as the alkyl hydroxyperoxide reductase, the glycolytic pathway and several genes coding for enzymes involved in redox reactions. In the present work, we discuss the molecular mechanisms underlying the aerotolerance phenotype of B. bifidum IPLA60003, which will open new strategies for the selection and inclusion of probiotic gut strains and next generation probiotics into functional foods.
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Affiliation(s)
- Raquel Marcos-Fernández
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Aitor Blanco-Míguez
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Lorena Ruiz
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Abelardo Margolles
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain
| | - Patricia Ruas-Madiedo
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain.
| | - Borja Sánchez
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Department of Microbiology and Biochemistry of Dairy Products, Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Asturias, Spain.
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14
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Improving glycine utilization in Escherichia coli. Biochem Eng J 2023. [DOI: 10.1016/j.bej.2023.108834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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15
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Li L, Dong H, Lu Y, Zhang H, Li Y, Xiao J, Xiao S, Jin Z. In-depth exploration of toxicity mechanism of nanoscale zero-valent iron and its aging products toward Escherichia coli under aerobic and anaerobic conditions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 313:120118. [PMID: 36087891 DOI: 10.1016/j.envpol.2022.120118] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/22/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
The bacteria toxicity of nanoscale zero-valent iron (nZVI) can be changed during its application in water treatment but the toxicity mechanism is still not well understood, particularly under anaerobic conditions. Here, the toxicity of nZVI and its aging products towards Escherichia coli (E. coli) and the mechanisms of extracellular and intracellular reactive oxygen species (ROS) damage were deeply probed in the presence and absence of oxygen in ultrapure water. Under aerobic conditions, the ROS damage primarily caused by the generation of extracellular free •OH can be a major contributor to the toxicity of nZVI to E. coli. By contrast, in anaerobic nZVI treatment system, the intracellular •OH can be quenched by benzoic acid which is a cell permeable quencher and the electron spin resonance (ESR) signals of 5,5-dimethy-1-pyrroline (DMPO)- •OH were evidently observed in system with the addition of F- which could desorb the surface •OH into solution. It indicated that the intracellular •OH adsorbed on the particle surface can also play an indispensable role in inactivating cells under anaerobic conditions. Moreover, nZVI can steeply decline the membrane potential, causing severe membrane disruption and therefore resulting in the stronger toxicity in anaerobic conditions. Furthermore, the chemical composition transformation of nZVI and generation of benign iron corrosion products (e.g., Fe3O4, γ-Fe2O3, γ-FeOOH) are mainly responsible for the reduced toxicity with the increasing aging time. These results provide insights into the extracellular and intracellular ROS damage occurred in aerobic and anaerobic nZVI treatment systems, offering more perspective to the risk assessment of nZVI application.
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Affiliation(s)
- Long Li
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Haoran Dong
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China.
| | - Yue Lu
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Haoxuan Zhang
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Yangju Li
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Junyang Xiao
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Shuangjie Xiao
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
| | - Zilan Jin
- College of Environmental Science and Engineering, Hunan University, Changsha, Hunan, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, Hunan, 410082, China
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16
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Park M, Kim J, Feinstein J, Lang KS, Ryu S, Jeon B. Development of Fluoroquinolone Resistance through Antibiotic Tolerance in Campylobacter jejuni. Microbiol Spectr 2022; 10:e0166722. [PMID: 36066254 PMCID: PMC9602944 DOI: 10.1128/spectrum.01667-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 08/18/2022] [Indexed: 12/31/2022] Open
Abstract
Antibiotic tolerance not only enables bacteria to survive acute antibiotic exposures but also provides bacteria with a window of time in which to develop antibiotic resistance. The increasing prevalence of Campylobacter jejuni isolates resistant to clinically important antibiotics, particularly fluoroquinolones (FQs), is a global public health concern. Currently, little is known about antibiotic tolerance and its effects on resistance development in C. jejuni. Here, we show that exposure to ciprofloxacin or tetracycline at concentrations 10 and 100 times higher than the MIC induces antibiotic tolerance in C. jejuni, whereas gentamicin or erythromycin treatment causes cell death. Interestingly, FQ resistance rapidly develops in C. jejuni after tolerance induction by ciprofloxacin and tetracycline. Furthermore, after tolerance is induced, alkyl hydroperoxide reductase (AhpC) plays a critical role in reducing FQ resistance development by alleviating oxidative stress. Together, these results demonstrate that exposure of C. jejuni to antibiotics can induce antibiotic tolerance and that FQ-resistant (FQR) C. jejuni clones rapidly emerge after tolerance induction. This study elucidates the mechanisms underlying the high prevalence of FQR C. jejuni and provides insights into the effects of antibiotic tolerance on resistance development. IMPORTANCE Antibiotic tolerance compromises the efficacy of antibiotic treatment by extending bacterial survival and facilitating the development of mutations associated with antibiotic resistance. Despite growing public health concerns about antibiotic resistance in C. jejuni, antibiotic tolerance has not yet been investigated in this important zoonotic pathogen. Here, our results show that exposure of C. jejuni to ciprofloxacin or tetracycline leads to antibiotic tolerance development, which subsequently facilitates the emergence of FQR C. jejuni. Importantly, these antibiotics are commonly used in animal agriculture. Moreover, our study suggests that the use of non-FQ drugs in animal agriculture promotes FQ resistance development, which is crucial because antibiotic-resistant C. jejuni is primarily transmitted from animals to humans. Overall, these findings increase our understanding of the mechanisms of resistance development through the induction of antibiotic tolerance.
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Affiliation(s)
- Myungseo Park
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Saint Paul, Minnesota, USA
| | - Jinshil Kim
- Department of Food and Animal Biotechnology, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul, Republic of Korea
| | - Jill Feinstein
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Saint Paul, Minnesota, USA
| | - Kevin S. Lang
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, Minnesota, USA
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
- Center for Food and Bioconvergence, Seoul National University, Seoul, Republic of Korea
| | - Byeonghwa Jeon
- Division of Environmental Health Sciences, School of Public Health, University of Minnesota, Saint Paul, Minnesota, USA
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17
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Ketcham A, Freddolino PL, Tavazoie S. Intracellular acidification is a hallmark of thymineless death in E. coli. PLoS Genet 2022; 18:e1010456. [PMID: 36279294 PMCID: PMC9632930 DOI: 10.1371/journal.pgen.1010456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 11/03/2022] [Accepted: 10/01/2022] [Indexed: 11/05/2022] Open
Abstract
Thymidine starvation causes rapid cell death. This enigmatic process known as thymineless death (TLD) is the underlying killing mechanism of diverse antimicrobial and antineoplastic drugs. Despite decades of investigation, we still lack a mechanistic understanding of the causal sequence of events that culminate in TLD. Here, we used a diverse set of unbiased approaches to systematically determine the genetic and regulatory underpinnings of TLD in Escherichia coli. In addition to discovering novel genes in previously implicated pathways, our studies revealed a critical and previously unknown role for intracellular acidification in TLD. We observed that a decrease in cytoplasmic pH is a robust early event in TLD across different genetic backgrounds. Furthermore, we show that acidification is a causal event in the death process, as chemical and genetic perturbations that increase intracellular pH substantially reduce killing. We also observe a decrease in intracellular pH in response to exposure to the antibiotic gentamicin, suggesting that intracellular acidification may be a common mechanistic step in the bactericidal effects of other antibiotics.
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Affiliation(s)
- Alexandra Ketcham
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
- Department of Systems Biology, Columbia University, New York, New York, United States of America
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
| | - Peter L. Freddolino
- Department of Systems Biology, Columbia University, New York, New York, United States of America
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
| | - Saeed Tavazoie
- Department of Biological Sciences, Columbia University, New York, New York, United States of America
- Department of Systems Biology, Columbia University, New York, New York, United States of America
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York, United States of America
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18
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Seregina TA, Lobanov KV, Shakulov RS, Mironov AS. Inactivation of Terminal Oxidase bd-I Leads to Supersensitivity of E. coli to Quinolone and Beta-Lactam Antibiotics. Mol Biol 2022. [DOI: 10.1134/s0026893322040100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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19
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Forte E, Nastasi MR, Borisov VB. Preparations of Terminal Oxidase Cytochrome bd-II Isolated from Escherichia coli Reveal Significant Hydrogen Peroxide Scavenging Activity. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:720-730. [PMID: 36171653 DOI: 10.1134/s0006297922080041] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/29/2022] [Accepted: 04/29/2022] [Indexed: 06/16/2023]
Abstract
Cytochrome bd-II is one of the three terminal quinol oxidases of the aerobic respiratory chain of Escherichia coli. Preparations of the detergent-solubilized untagged bd-II oxidase isolated from the bacterium were shown to scavenge hydrogen peroxide (H2O2) with high rate producing molecular oxygen (O2). Addition of H2O2 to the same buffer that does not contain enzyme or contains thermally denatured cytochrome bd-II does not lead to any O2 production. The latter observation rules out involvement of adventitious transition metals bound to the protein. The H2O2-induced O2 production is not susceptible to inhibition by N-ethylmaleimide (the sulfhydryl binding compound), antimycin A (the compound that binds specifically to a quinol binding site), and CO (diatomic gas that binds specifically to the reduced heme d). However, O2 formation is inhibited by cyanide (IC50 = 4.5 ± 0.5 µM) and azide. Addition of H2O2 in the presence of dithiothreitol and ubiquinone-1 does not inactivate cytochrome bd-II and apparently does not affect the O2 reductase activity of the enzyme. The ability of cytochrome bd-II to detoxify H2O2 could play a role in bacterial physiology by conferring resistance to the peroxide-mediated stress.
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Affiliation(s)
- Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, I-00185, Italy
| | - Martina R Nastasi
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, I-00185, Italy
| | - Vitaliy B Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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20
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Impaired Succinate Oxidation Prevents Growth and Influences Drug Susceptibility in Mycobacterium tuberculosis. mBio 2022; 13:e0167222. [PMID: 35856639 PMCID: PMC9426501 DOI: 10.1128/mbio.01672-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Succinate is a major focal point in mycobacterial metabolism and respiration, serving as both an intermediate of the tricarboxylic acid (TCA) cycle and a direct electron donor for the respiratory chain. Mycobacterium tuberculosis encodes multiple enzymes predicted to be capable of catalyzing the oxidation of succinate to fumarate, including two different succinate dehydrogenases (Sdh1 and Sdh2) and a separate fumarate reductase (Frd) with possible bidirectional behavior. Previous attempts to investigate the essentiality of succinate oxidation in M. tuberculosis have relied on the use of single-gene deletion mutants, raising the possibility that the remaining enzymes could catalyze succinate oxidation in the absence of the other. To address this, we report on the use of mycobacterial CRISPR interference (CRISPRi) to construct single, double, and triple transcriptional knockdowns of sdhA1, sdhA2, and frdA in M. tuberculosis. We show that the simultaneous knockdown of sdhA1 and sdhA2 is required to prevent succinate oxidation and overcome the functional redundancy within these enzymes. Succinate oxidation was demonstrated to be essential for the optimal growth of M. tuberculosis, with the combined knockdown of sdhA1 and sdhA2 significantly impairing the activity of the respiratory chain and preventing growth on a range of carbon sources. Moreover, impaired succinate oxidation was shown to influence the activity of cell wall-targeting antibiotics and bioenergetic inhibitors against M. tuberculosis. Together, these data provide fundamental insights into mycobacterial physiology, energy metabolism, and antimicrobial susceptibility. IMPORTANCE New drugs are urgently required to combat the tuberculosis epidemic that claims 1.5 million lives annually. Inhibitors of mycobacterial energy metabolism have shown significant promise clinically; however, further advancing this nascent target space requires a more fundamental understanding of the respiratory enzymes and pathways used by Mycobacterium tuberculosis. Succinate is a major focal point in mycobacterial metabolism and respiration; yet, the essentiality of succinate oxidation and the consequences of inhibiting this process are poorly defined. In this study, we demonstrate that impaired succinate oxidation prevents the optimal growth of M. tuberculosis on a range of carbon sources and significantly reduces the activity of the electron transport chain. Moreover, we show that impaired succinate oxidation both positively and negatively influences the activity of a variety of antituberculosis drugs. Combined, these findings provide fundamental insights into mycobacterial physiology and drug susceptibility that will be useful in the continued development of bioenergetic inhibitors.
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21
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Eisenreich W, Rudel T, Heesemann J, Goebel W. Link Between Antibiotic Persistence and Antibiotic Resistance in Bacterial Pathogens. Front Cell Infect Microbiol 2022; 12:900848. [PMID: 35928205 PMCID: PMC9343593 DOI: 10.3389/fcimb.2022.900848] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 06/21/2022] [Indexed: 12/15/2022] Open
Abstract
Both, antibiotic persistence and antibiotic resistance characterize phenotypes of survival in which a bacterial cell becomes insensitive to one (or even) more antibiotic(s). However, the molecular basis for these two antibiotic-tolerant phenotypes is fundamentally different. Whereas antibiotic resistance is genetically determined and hence represents a rather stable phenotype, antibiotic persistence marks a transient physiological state triggered by various stress-inducing conditions that switches back to the original antibiotic sensitive state once the environmental situation improves. The molecular basics of antibiotic resistance are in principle well understood. This is not the case for antibiotic persistence. Under all culture conditions, there is a stochastically formed, subpopulation of persister cells in bacterial populations, the size of which depends on the culture conditions. The proportion of persisters in a bacterial population increases under different stress conditions, including treatment with bactericidal antibiotics (BCAs). Various models have been proposed to explain the formation of persistence in bacteria. We recently hypothesized that all physiological culture conditions leading to persistence converge in the inability of the bacteria to re-initiate a new round of DNA replication caused by an insufficient level of the initiator complex ATP-DnaA and hence by the lack of formation of a functional orisome. Here, we extend this hypothesis by proposing that in this persistence state the bacteria become more susceptible to mutation-based antibiotic resistance provided they are equipped with error-prone DNA repair functions. This is - in our opinion - in particular the case when such bacterial populations are exposed to BCAs.
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Affiliation(s)
- Wolfgang Eisenreich
- Bavarian NMR Center – Structural Membrane Biochemistry, Department of Chemistry, Technische Universität München, Garching, Germany
- *Correspondence: Wolfgang Eisenreich,
| | - Thomas Rudel
- Chair of Microbiology, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jürgen Heesemann
- Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich, München, Germany
| | - Werner Goebel
- Max von Pettenkofer-Institute, Ludwig Maximilian University of Munich, München, Germany
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22
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Salmonella Central Carbon Metabolism Enhances Bactericidal Killing by Fluoroquinolone Antibiotics. Antimicrob Agents Chemother 2022; 66:e0234421. [PMID: 35658490 DOI: 10.1128/aac.02344-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The efficacy of killing by bactericidal antibiotics has been reported to depend in large part on the ATP levels, with low levels of ATP leading to increased persistence after antibiotic challenge. Here, we show that an atp operon deletion strain of Salmonella enterica serovar Typhimurium lacking the ATP synthase was at least 10-fold more sensitive to killing by the fluoroquinolone antibiotic ciprofloxacin and yet showed either increased survival or no significant difference compared with the wild-type strain when challenged with aminoglycoside or β-lactam antibiotics, respectively. The increased cell killing and reduced bacterial survival (persistence) after fluoroquinolone challenge were found to involve metabolic compensation for the loss of the ATP synthase through central carbon metabolism reactions and increased NAD(P)H levels. We conclude that the intracellular ATP levels per se do not correlate with bactericidal antibiotic persistence to fluoroquinolone killing; rather, the central carbon metabolic pathways active at the time of challenge and the intracellular target of the antibiotic determine the efficacy of treatment.
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23
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Lin L, Zou M, Lu Z. The aerobic electron flux is deficient in fumarate respiration of a strict anaerobe Bacteroides thetaiotaomicron. Biochem Biophys Res Commun 2022; 614:213-218. [PMID: 35623108 DOI: 10.1016/j.bbrc.2022.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/05/2022] [Indexed: 11/28/2022]
Abstract
Why oxygen ceases the growth of strictly anaerobic bacteria is a longstanding question, yet the answer remains unclear. Studies have confirmed that the dehydratase-fumarase containing an iron-sulfur cluster ([4Fe-4S]) is inactivated upon exposure to oxygen in the intestinal obligate anaerobe, Bacteroides thetaiotaomicron (B. thetaiotaomicron); this blocks fumarate respiration, which is the essential energy-producing pathway in anaerobes. Here, we substituted the [4Fe-4S]-dependent fumarase in B. thetaiotaomicron with an iron-free isozyme from E. coli (Ec-FumC). Results show that Ec-FumC successfully performed the catalytic function of fumarase in B. thetaiotaomicron, as the fum-mutant strain that expressed Ec-FumC exhibited succinate-producing ability under anaerobic growth conditions. Ec-FumC is oxygen-resistant and remains active to produce fumarate upon aeration; however, B. thetaiotaomicron mutant that expressed Ec-FumC did not convert fumarate to succinate during air exposure. Biochemical assays of inverted membrane vesicles from wild-type B. thetaiotaomicron confirmed that the electron flux from NADH to fumarate was less efficient in the presence of air as compared to that without oxygen. Our findings suggest that the anaerobic fumarate respiration might be paralyzed due to electron dissipations upon aeration of the obligate anaerobe.
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Affiliation(s)
- Luyou Lin
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Meng Zou
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China
| | - Zheng Lu
- Department of Biology, Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Sciences, Shantou University, Shantou, 515063, China.
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Chautrand T, Souak D, Chevalier S, Duclairoir-Poc C. Gram-Negative Bacterial Envelope Homeostasis under Oxidative and Nitrosative Stress. Microorganisms 2022; 10:924. [PMID: 35630368 PMCID: PMC9144841 DOI: 10.3390/microorganisms10050924] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/15/2022] [Accepted: 04/21/2022] [Indexed: 12/15/2022] Open
Abstract
Bacteria are frequently exposed to endogenous and exogenous reactive oxygen and nitrogen species which can damage various biomolecules such as DNA, lipids, and proteins. High concentrations of these molecules can induce oxidative and nitrosative stresses in the cell. Reactive oxygen and nitrogen species are notably used as a tool by prokaryotes and eukaryotes to eradicate concurrent species or to protect themselves against pathogens. The main example is mammalian macrophages that liberate high quantities of reactive species to kill internalized bacterial pathogens. As a result, resistance to these stresses is determinant for the survival of bacteria, both in the environment and in a host. The first bacterial component in contact with exogenous molecules is the envelope. In Gram-negative bacteria, this envelope is composed of two membranes and a layer of peptidoglycan lodged between them. Several mechanisms protecting against oxidative and nitrosative stresses are present in the envelope, highlighting the importance for the cell to deal with reactive species in this compartment. This review aims to provide a comprehensive view of the challenges posed by oxidative and nitrosative stresses to the Gram-negative bacterial envelope and the mechanisms put in place in this compartment to prevent and repair the damages they can cause.
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Affiliation(s)
| | | | | | - Cécile Duclairoir-Poc
- Research Unit Bacterial Communication and Anti-infectious Strategies (UR CBSA), Rouen Normandy University, Normandy University, 55 rue Saint-Germain, 27000 Evreux, France; (T.C.); (D.S.); (S.C.)
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25
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Luo Z, Wang Z, Wang B, Lu Y, Yan L, Zhao Z, Bai T, Zhang J, Li H, Wang W, Cheng J. An Artificial Pathway for N-Hydroxy-Pipecolic Acid Production From L-Lysine in Escherichia coli. Front Microbiol 2022; 13:842804. [PMID: 35350620 PMCID: PMC8957990 DOI: 10.3389/fmicb.2022.842804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/26/2022] [Indexed: 11/30/2022] Open
Abstract
N-hydroxy-pipecolic acid (NHP) is a hydroxylated product of pipecolic acid and an important systemic acquired resistance signal molecule. However, the biosynthesis of NHP does not have a natural metabolic pathway in microorganisms. Here, we designed and constructed a promising artificial pathway in Escherichia coli for the first time to produce NHP from biomass-derived lysine. This biosynthesis route expands the lysine catabolism pathway and employs six enzymes to sequentially convert lysine into NHP. This artificial route involves six functional enzyme coexpression: lysine α-oxidase from Scomber japonicus (RaiP), glucose dehydrogenase from Bacillus subtilis (GDH), Δ1-piperideine-2-carboxylase reductase from Pseudomonas putida (DpkA), lysine permease from E. coli (LysP), flavin-dependent monooxygenase (FMO1), and catalase from E. coli (KatE). Moreover, different FMO1s are used to evaluate the performance of the produce NHP. A titer of 111.06 mg/L of NHP was yielded in shake flasks with minimal medium containing 4 g/L of lysine. By this approach, NHP has so far been produced at final titers reaching 326.42 mg/L by 48 h in a 5-L bioreactor. To the best of our knowledge, this is the first NHP process using E. coli and the first process to directly synthesize NHP by microorganisms. This study lays the foundation for the development and utilization of renewable resources to produce NHP in microorganisms.
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Affiliation(s)
- Zhou Luo
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Zhen Wang
- College of Science and Technology, Hebei Agricultural University, Cangzhou, China
| | - Bangxu Wang
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Yao Lu
- College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou, China
| | - Lixiu Yan
- Chongqing Academy of Metrology and Quality Inspection, Chongqing, China
| | - Zhiping Zhao
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Ting Bai
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Jiamin Zhang
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Hanmei Li
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Wei Wang
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
| | - Jie Cheng
- Meat Processing Key Laboratory of Sichuan Province, College of Food and Biological Engineering, Chengdu University, Chengdu, China
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26
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RNase III Participates in the Adaptation to Temperature Shock and Oxidative Stress in Escherichia coli. Microorganisms 2022; 10:microorganisms10040699. [PMID: 35456749 PMCID: PMC9032294 DOI: 10.3390/microorganisms10040699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 02/05/2023] Open
Abstract
Bacteria thrive in ever-changing environments by quickly remodeling their transcriptome and proteome via complex regulatory circuits. Regulation occurs at multiple steps, from the transcription of genes to the post-translational modification of proteins, via both protein and RNA regulators. At the post-transcriptional level, the RNA fate is balanced through the binding of ribosomes, chaperones and ribonucleases. We aim to decipher the role of the double-stranded-RNA-specific endoribonuclease RNase III and to evaluate its biological importance in the adaptation to modifications of the environment. The inactivation of RNase III affects a large number of genes and leads to several phenotypical defects, such as reduced thermotolerance in Escherichia coli. In this study, we reveal that RNase III inactivation leads to an increased sensitivity to temperature shock and oxidative stress. We further show that RNase III is important for the induction of the heat shock sigma factor RpoH and for the expression of the superoxide dismutase SodA.
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27
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Abstract
Over the last decade, the genomes of several Bifidobacterium strains have been sequenced, delivering valuable insights into their genetic makeup. However, bifidobacterial genomes have not yet been systematically mined for genes associated with stress response functions and their regulation. In this work, a list of 76 genes related to stress response in bifidobacteria was compiled from previous studies. The prevalence of the genes was evaluated among the genome sequences of 171 Bifidobacterium strains. Although genes of the protein quality control and DNA repair systems appeared to be highly conserved, genome-wide in silico screening for consensus sequences of putative regulators suggested that the regulation of these systems differs among phylogenetic groups. Homologs of multiple oxidative stress-associated genes are shared across species, albeit at low sequence similarity. Bee isolates were confirmed to harbor unique genetic features linked to oxygen tolerance. Moreover, most studied Bifidobacterium adolescentis and all Bifidobacterium angulatum strains lacked a set of reactive oxygen species-detoxifying enzymes, which might explain their high sensitivity to oxygen. Furthermore, the presence of some putative transcriptional regulators of stress responses was found to vary across species and strains, indicating that different regulation strategies of stress-associated gene transcription contribute to the diverse stress tolerance. The presented stress response gene profiles of Bifidobacterium strains provide a valuable knowledge base for guiding future studies by enabling hypothesis generation and the identification of key genes for further analyses. IMPORTANCE Bifidobacteria are Gram-positive bacteria that naturally inhabit diverse ecological niches, including the gastrointestinal tract of humans and animals. Strains of the genus Bifidobacterium are widely used as probiotics, since they have been associated with health benefits. In the course of their production and administration, probiotic bifidobacteria are exposed to several stressors that can challenge their survival. The stress tolerance of probiotic bifidobacteria is, therefore, an important selection criterion for their commercial application, since strains must maintain their viability to exert their beneficial health effects. As the ability to cope with stressors varies among Bifidobacterium strains, comprehensive understanding of the underlying stress physiology is required for enabling knowledge-driven strain selection and optimization of industrial-scale production processes.
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28
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Chen Z, Fei K, Hu Y, Xu X, Gao XD, Li Z. Identification of a Novel Alditol Oxidase from Thermopolyspora flexuosa with Potential Application in D-Glyceric Acid Production. Mol Biotechnol 2022; 64:804-813. [PMID: 35129810 DOI: 10.1007/s12033-022-00459-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/30/2022] [Indexed: 10/19/2022]
Abstract
Glycerol is a potential sustainable feedstock, and biorefining processes to convert glycerol into value-added chemicals have been developed over the past decade. Alditol oxidase (AldO) is capable of selectively oxidizing the primary hydroxyl groups of alditols such as glycerol. In this study, a new FAD-binding protein from Thermopolyspora flexuosa was expressed and identified as a novel alditol oxidase (AldOT. fle). AldOT. fle displayed the optimal activity at pH 8.0 and 25 °C. AldOT. fle was not metal-dependent, but the activity was completely inhibited by Fe3+. AldOT. fle had a wide substrate specificity and high catalytic efficiency for glycerol. Furthermore, the recombinant AldOT. fle could produce D-glyceric acid from glycerol with a conversion rate ranging from 86.6% (5 mM glycerol) to 20.5% (500 mM glycerol). The recombinant E. coli with AldOT. fle could also produce 23.8 mM D-glyceric acid from 100 mM glycerol. The recombinant AldOT. fle had the potential to produce other aldehyde products by selectively oxidizing the hydroxyl groups of alditols and many other commodity chemicals by redesigning glycerol metabolism.
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Affiliation(s)
- Zhou Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Kangqing Fei
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Yangfan Hu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Xiangyang Xu
- Zaozhuang Jienuo Enzyme Co., Ltd, Zaozhuang, 277100, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Zijie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China.
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29
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Chakravarty D, Bihani SC, Banerjee M, Kalwani P, Ballal A. Unique functional insights into the antioxidant response of the cyanobacterial Mn-catalase (KatB). Free Radic Biol Med 2022; 179:266-276. [PMID: 34793931 DOI: 10.1016/j.freeradbiomed.2021.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 11/12/2021] [Indexed: 01/06/2023]
Abstract
KatB, a hexameric Mn-catalase, plays a vital role in overcoming oxidative and salinity stress in the ecologically important, N2-fixing cyanobacterium, Anabaena. The 5 N-terminal residues of KatB, which show a high degree of conservation in cyanobacteria, form an antiparallel β-strand at the subunit interface of the KatB hexamer. In this study, the contribution of these N-terminal non-active site residues, towards the maintenance of the structure, biochemical properties, and redox balance was evaluated. Each N-terminal amino acid residue from the 2nd to the 7th position of KatB was individually mutated to Ala (to express KatBF2A/KatBF3A/KatBH4A/KatBK5E/KatBK6A/KatBE7A) or this entire 6 amino acid stretch was deleted (to yield KatBTrunc). All the above-mentioned KatB variants, along with the wild-type KatB protein (KatBWT), were overproduced in E. coli and purified. In comparison to KatBWT, the KatBF2A/KatBH4A/KatBTrunc proteins were less compact, more prone to chemical/thermal denaturation, and were unexpectedly inactive. KatBF3A/KatBK5E/KatBK6A showed biophysical/biochemical properties that were in between that of KatBWT and KatBF2A/KatBH4A/KatBTrunc. Surprisingly, KatBE7A was more thermostable with higher activity than KatBWT. On exposure to H2O2, E. coli expressing KatBWT/KatBE7A showed considerably reduced formation of ROS and increased survival than the other KatB variants. Utilizing the KatB structure, the molecular basis responsible for the altered stability/activity of the KatB mutants was delineated. This study demonstrates the physiological importance of the N-terminal β-strand of Mn-catalases in combating H2O2 stress and shows that the non-active site residues can be used for rational protein engineering to develop Mn-catalases with improved characteristics.
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Affiliation(s)
- Dhiman Chakravarty
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Subhash C Bihani
- Radiation Biology & Health Sciences Division, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
| | - Manisha Banerjee
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Prakash Kalwani
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India
| | - Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai, 400094, India.
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30
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Gupta A, Imlay JA. Escherichia coli induces DNA repair enzymes to protect itself from low-grade hydrogen peroxide stress. Mol Microbiol 2021; 117:754-769. [PMID: 34942039 DOI: 10.1111/mmi.14870] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/18/2021] [Accepted: 12/18/2021] [Indexed: 11/30/2022]
Abstract
E. coli responds to hydrogen peroxide (H2 O2 ) by inducing defenses that protect H2 O2 -sensitive enzymes. DNA is believed to be another important target of oxidation, and E. coli contains enzymes that can repair oxidative lesions in vitro. However, those enzymes are not known to be induced by H2 O2 , and experiments have indicated that they are not necessary for the cell to withstand natural (low-micromolar) concentrations. In this study we used H2 O2 -scavenging mutants to impose controlled doses of H2 O2 for extended time. Transcriptomic analysis revealed that in the presence of 1 µM cytoplasmic H2 O2 , the OxyR transcription factor induced xthA, encoding exonuclease III. The xthA mutants survived a conventional 15-minute exposure to even 100 times this level of H2 O2 . However, when these mutants were exposed to 1 µM H2 O2 for hours, they accumulated DNA lesions, failed to propagate, and eventually died. Although endonuclease III (nth) was not induced, nth mutants struggled to grow. Low-grade H2 O2 stress also activated the SOS regulon, and when this induction was blocked, cell replication stopped. Collectively, these data indicate that physiological levels of H2 O2 are a real threat to DNA, and the engagement of the base-excision-repair and SOS systems is necessary to enable propagation during protracted stress.
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Affiliation(s)
- Anshika Gupta
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave, Urbana, IL, 61801, USA
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31
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Gugala N, Salazar-Alemán DA, Chua G, Turner RJ. Using a chemical genetic screen to enhance our understanding of the antimicrobial properties of copper. Metallomics 2021; 14:6449381. [PMID: 34865058 DOI: 10.1093/mtomcs/mfab071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 11/30/2021] [Indexed: 11/12/2022]
Abstract
The competitive toxic and stress inducing nature of copper necessitates systems that sequester and export this metal from the cytoplasm of bacterial cells. Several predicted mechanisms of toxicity include the production of reactive oxygen species, thiol depletion, DNA and iron-sulfur cluster disruption. Accompanying these mechanisms include pathways of homeostasis such as chelation, oxidation, and transport. Still, the mechanisms of copper resistance and sensitivity are not fully understood. Furthermore, studies fail to recognize that the response to copper is likely a result of numerous mechanisms, as in the case for homeostasis, in which proteins and enzymes work as a collective to maintain appropriate copper concentrations. In this study we used the Keio collection, an array of 3985 Escherichia coli mutants, each with a deleted non-essential gene, to gain a better understanding of prolonged copper exposure. In short, we recovered two copper homeostatic gene and genes involved in transporting and assembling to be involved in mediating prolonged copper stress under the conditions assessed. The gene coding for the protein TolC was uncovered as a sensitive hit and we demonstrated that tolC, an outer membrane efflux channel, is key in mitigating copper sensitivity. Additionally, the activity of tRNA processing was enriched and the deletion of several proteins involved in import generated copper tolerance. Lastly, key genes belonging to central carbon metabolism and nicotinamide adenine dinucleotide biosynthesis were uncovered as tolerant hits. Overall, this study shows that copper sensitivity and tolerance are a result of numerous mechanisms acting in combination within the cell.
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Affiliation(s)
- Natalie Gugala
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | | | - Gordon Chua
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada
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32
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When anaerobes encounter oxygen: mechanisms of oxygen toxicity, tolerance and defence. Nat Rev Microbiol 2021; 19:774-785. [PMID: 34183820 PMCID: PMC9191689 DOI: 10.1038/s41579-021-00583-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/19/2021] [Indexed: 02/06/2023]
Abstract
The defining trait of obligate anaerobes is that oxygen blocks their growth, yet the underlying mechanisms are unclear. A popular hypothesis was that these microorganisms failed to evolve defences to protect themselves from reactive oxygen species (ROS) such as superoxide and hydrogen peroxide, and that this failure is what prevents their expansion to oxic habitats. However, studies reveal that anaerobes actually wield most of the same defences that aerobes possess, and many of them have the capacity to tolerate substantial levels of oxygen. Therefore, to understand the structures and real-world dynamics of microbial communities, investigators have examined how anaerobes such as Bacteroides, Desulfovibrio, Pyrococcus and Clostridium spp. struggle and cope with oxygen. The hypoxic environments in which these organisms dwell - including the mammalian gut, sulfur vents and deep sediments - experience episodic oxygenation. In this Review, we explore the molecular mechanisms by which oxygen impairs anaerobes and the degree to which bacteria protect their metabolic pathways from it. The emergent view of anaerobiosis is that optimal strategies of anaerobic metabolism depend upon radical chemistry and low-potential metal centres. Such catalytic sites are intrinsically vulnerable to direct poisoning by molecular oxygen and ROS. Observations suggest that anaerobes have evolved tactics that either minimize the extent to which oxygen disrupts their metabolism or restore function shortly after the stress has dissipated.
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33
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Qin Z, Yu S, Chen J, Zhou J. Dehydrogenases of acetic acid bacteria. Biotechnol Adv 2021; 54:107863. [PMID: 34793881 DOI: 10.1016/j.biotechadv.2021.107863] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 12/13/2022]
Abstract
Acetic acid bacteria (AAB) are a group of bacteria that can oxidize many substrates such as alcohols and sugar alcohols and play important roles in industrial biotechnology. A majority of industrial processes that involve AAB are related to their dehydrogenases, including PQQ/FAD-dependent membrane-bound dehydrogenases and NAD(P)+-dependent cytoplasmic dehydrogenases. These cofactor-dependent dehydrogenases must effectively regenerate their cofactors in order to function continuously. For PQQ, FAD and NAD(P)+ alike, regeneration is directly or indirectly related to the electron transport chain (ETC) of AAB, which plays an important role in energy generation for aerobic cell growth. Furthermore, in changeable natural habitats, ETC components of AAB can be regulated so that the bacteria survive in different environments. Herein, the progressive cascade in an application of AAB, including key dehydrogenases involved in the application, regeneration of dehydrogenase cofactors, ETC coupling with cofactor regeneration and ETC regulation, is systematically reviewed and discussed. As they have great application value, a deep understanding of the mechanisms through which AAB function will not only promote their utilization and development but also provide a reference for engineering of other industrial strains.
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Affiliation(s)
- Zhijie Qin
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Shiqin Yu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jian Chen
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China
| | - Jingwen Zhou
- School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China; Jiangsu Provisional Research Center for Bioactive Product Processing Technology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
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34
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Looking into a highly thermostable and efficient recombinant manganese-catalase from Geobacillusthermopakistaniensis. J Biosci Bioeng 2021; 133:25-32. [PMID: 34642121 DOI: 10.1016/j.jbiosc.2021.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/09/2021] [Accepted: 09/17/2021] [Indexed: 01/17/2023]
Abstract
Catalases, heme or non-heme, are catalysts that decompose hydrogen peroxide. Among them, non-heme or manganese-catalases have been studied from limited organisms. We report here heterologous production of a manganese-catalase, Cat-IIGt, previously annotated as a hypothetical protein, from a thermophilic bacterium Geobacillus thermopakistaniensis. Recombinant Cat-IIGt, produced as inactive inclusion bodies in Escherichia coli, was solubilized and refolded into a soluble and highly active form. Sequence homology, absorption spectra, resistance to sodium azide inhibition and activation by Mn2+ indicated that it was a manganese-catalase. Metal analysis revealed the presence of ∼2 Mn2+ and ∼2 Ca2+ per subunit of Cat-IIGt. Recombinant Cat-IIGt exhibited highest activity at pH 10.0 and 70°C. The enzyme was highly active with a specific activity of 40,529 μmol min-1 mg-1. The apparent Km and kcat values were 75 mM and 1.5 × 104 s-1 subunit-1, respectively. Recombinant Cat-IIGt was highly thermostable with a half-life of 30 min at 100°C. The structural attributes of Cat-IIGt, including the metal and substrate binding residues, were predicted by homology modeling and molecular docking studies. High activity and thermostability and alkaline nature make Cat-IIGt a potential candidate for textile and paper processing industries.
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35
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Oxidative Stress Response in Pseudomonas aeruginosa. Pathogens 2021; 10:pathogens10091187. [PMID: 34578219 PMCID: PMC8466533 DOI: 10.3390/pathogens10091187] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/06/2021] [Accepted: 09/08/2021] [Indexed: 12/17/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative environmental and human opportunistic pathogen highly adapted to many different environmental conditions. It can cause a wide range of serious infections, including wounds, lungs, the urinary tract, and systemic infections. The high versatility and pathogenicity of this bacterium is attributed to its genomic complexity, the expression of several virulence factors, and its intrinsic resistance to various antimicrobials. However, to thrive and establish infection, P. aeruginosa must overcome several barriers. One of these barriers is the presence of oxidizing agents (e.g., hydrogen peroxide, superoxide, and hypochlorous acid) produced by the host immune system or that are commonly used as disinfectants in a variety of different environments including hospitals. These agents damage several cellular molecules and can cause cell death. Therefore, bacteria adapt to these harsh conditions by altering gene expression and eliciting several stress responses to survive under oxidative stress. Here, we used PubMed to evaluate the current knowledge on the oxidative stress responses adopted by P. aeruginosa. We will describe the genes that are often differently expressed under oxidative stress conditions, the pathways and proteins employed to sense and respond to oxidative stress, and how these changes in gene expression influence pathogenicity and the virulence of P. aeruginosa. Understanding these responses and changes in gene expression is critical to controlling bacterial pathogenicity and developing new therapeutic agents.
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Counts JA, Willard DJ, Kelly RM. Life in hot acid: a genome-based reassessment of the archaeal order Sulfolobales. Environ Microbiol 2021; 23:3568-3584. [PMID: 32776389 PMCID: PMC10560490 DOI: 10.1111/1462-2920.15189] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 01/07/2023]
Abstract
The order Sulfolobales was one of the first named Archaeal lineages, with globally distributed members from terrestrial thermal acid springs (pH < 4; T > 65°C). The Sulfolobales represent broad metabolic capabilities, ranging from lithotrophy, based on inorganic iron and sulfur biotransformations, to autotrophy, to chemoheterotrophy in less acidophilic species. Components of the 3-hydroxypropionate/4-hydroxybutyrate carbon fixation cycle, as well as sulfur oxidation, are nearly universally conserved, although dissimilatory sulfur reduction and disproportionation (Acidianus, Stygiolobus and Sulfurisphaera) and iron oxidation (Acidianus, Metallosphaera, Sulfurisphaera, Sulfuracidifex and Sulfodiicoccus) are limited to fewer lineages. Lithotrophic marker genes appear more often in highly acidophilic lineages. Despite the presence of facultative anaerobes and one confirmed obligate anaerobe, oxidase complexes (fox, sox, dox and a new putative cytochrome bd) are prevalent in many species (even facultative/obligate anaerobes), suggesting a key role for oxygen among the Sulfolobales. The presence of fox genes tracks with a putative antioxidant OsmC family peroxiredoxin, an indicator of oxidative stress derived from mixing reactive metals and oxygen. Extreme acidophily appears to track inversely with heterotrophy but directly with lithotrophy. Recent phylogenetic re-organization efforts are supported by the comparative genomics here, although several changes are proposed, including the expansion of the genus Saccharolobus.
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Affiliation(s)
- James A. Counts
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Daniel J. Willard
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695 USA
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Borisov VB, Siletsky SA, Paiardini A, Hoogewijs D, Forte E, Giuffrè A, Poole RK. Bacterial Oxidases of the Cytochrome bd Family: Redox Enzymes of Unique Structure, Function, and Utility As Drug Targets. Antioxid Redox Signal 2021; 34:1280-1318. [PMID: 32924537 PMCID: PMC8112716 DOI: 10.1089/ars.2020.8039] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 12/23/2022]
Abstract
Significance: Cytochrome bd is a ubiquinol:oxygen oxidoreductase of many prokaryotic respiratory chains with a unique structure and functional characteristics. Its primary role is to couple the reduction of molecular oxygen, even at submicromolar concentrations, to water with the generation of a proton motive force used for adenosine triphosphate production. Cytochrome bd is found in many bacterial pathogens and, surprisingly, in bacteria formally denoted as anaerobes. It endows bacteria with resistance to various stressors and is a potential drug target. Recent Advances: We summarize recent advances in the biochemistry, structure, and physiological functions of cytochrome bd in the light of exciting new three-dimensional structures of the oxidase. The newly discovered roles of cytochrome bd in contributing to bacterial protection against hydrogen peroxide, nitric oxide, peroxynitrite, and hydrogen sulfide are assessed. Critical Issues: Fundamental questions remain regarding the precise delineation of electron flow within this multihaem oxidase and how the extraordinarily high affinity for oxygen is accomplished, while endowing bacteria with resistance to other small ligands. Future Directions: It is clear that cytochrome bd is unique in its ability to confer resistance to toxic small molecules, a property that is significant for understanding the propensity of pathogens to possess this oxidase. Since cytochrome bd is a uniquely bacterial enzyme, future research should focus on harnessing fundamental knowledge of its structure and function to the development of novel and effective antibacterial agents.
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Affiliation(s)
- Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Sergey A. Siletsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | | | - David Hoogewijs
- Department of Medicine/Physiology, University of Fribourg, Fribourg, Switzerland
| | - Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | | | - Robert K. Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, United Kingdom
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Borisov VB, Siletsky SA, Nastasi MR, Forte E. ROS Defense Systems and Terminal Oxidases in Bacteria. Antioxidants (Basel) 2021; 10:antiox10060839. [PMID: 34073980 PMCID: PMC8225038 DOI: 10.3390/antiox10060839] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 02/07/2023] Open
Abstract
Reactive oxygen species (ROS) comprise the superoxide anion (O2•−), hydrogen peroxide (H2O2), hydroxyl radical (•OH), and singlet oxygen (1O2). ROS can damage a variety of macromolecules, including DNA, RNA, proteins, and lipids, and compromise cell viability. To prevent or reduce ROS-induced oxidative stress, bacteria utilize different ROS defense mechanisms, of which ROS scavenging enzymes, such as superoxide dismutases, catalases, and peroxidases, are the best characterized. Recently, evidence has been accumulating that some of the terminal oxidases in bacterial respiratory chains may also play a protective role against ROS. The present review covers this role of terminal oxidases in light of recent findings.
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Affiliation(s)
- Vitaliy B. Borisov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russia;
- Correspondence: (V.B.B.); (E.F.)
| | - Sergey A. Siletsky
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991 Moscow, Russia;
| | - Martina R. Nastasi
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy;
| | - Elena Forte
- Department of Biochemical Sciences, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy;
- Correspondence: (V.B.B.); (E.F.)
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Fasnacht M, Polacek N. Oxidative Stress in Bacteria and the Central Dogma of Molecular Biology. Front Mol Biosci 2021; 8:671037. [PMID: 34041267 PMCID: PMC8141631 DOI: 10.3389/fmolb.2021.671037] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/26/2021] [Indexed: 11/13/2022] Open
Abstract
Ever since the "great oxidation event," Earth's cellular life forms had to cope with the danger of reactive oxygen species (ROS) affecting the integrity of biomolecules and hampering cellular metabolism circuits. Consequently, increasing ROS levels in the biosphere represented growing stress levels and thus shaped the evolution of species. Whether the ROS were produced endogenously or exogenously, different systems evolved to remove the ROS and repair the damage they inflicted. If ROS outweigh the cell's capacity to remove the threat, we speak of oxidative stress. The injuries through oxidative stress in cells are diverse. This article reviews the damage oxidative stress imposes on the different steps of the central dogma of molecular biology in bacteria, focusing in particular on the RNA machines involved in transcription and translation.
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Affiliation(s)
- Michel Fasnacht
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Norbert Polacek
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
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Sen A, Imlay JA. How Microbes Defend Themselves From Incoming Hydrogen Peroxide. Front Immunol 2021; 12:667343. [PMID: 33995399 PMCID: PMC8115020 DOI: 10.3389/fimmu.2021.667343] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/19/2021] [Indexed: 12/02/2022] Open
Abstract
Microbes rely upon iron as a cofactor for many enzymes in their central metabolic processes. The reactive oxygen species (ROS) superoxide and hydrogen peroxide react rapidly with iron, and inside cells they can generate both enzyme and DNA damage. ROS are formed in some bacterial habitats by abiotic processes. The vulnerability of bacteria to ROS is also apparently exploited by ROS-generating host defense systems and bacterial competitors. Phagocyte-derived O 2 - can toxify captured bacteria by damaging unidentified biomolecules on the cell surface; it is unclear whether phagocytic H2O2, which can penetrate into the cell interior, also plays a role in suppressing bacterial invasion. Both pathogenic and free-living microbes activate defensive strategies to defend themselves against incoming H2O2. Most bacteria sense the H2O2via OxyR or PerR transcription factors, whereas yeast uses the Grx3/Yap1 system. In general these regulators induce enzymes that reduce cytoplasmic H2O2 concentrations, decrease the intracellular iron pools, and repair the H2O2-mediated damage. However, individual organisms have tailored these transcription factors and their regulons to suit their particular environmental niches. Some bacteria even contain both OxyR and PerR, raising the question as to why they need both systems. In lab experiments these regulators can also respond to nitric oxide and disulfide stress, although it is unclear whether the responses are physiologically relevant. The next step is to extend these studies to natural environments, so that we can better understand the circumstances in which these systems act. In particular, it is important to probe the role they may play in enabling host infection by microbial pathogens.
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Affiliation(s)
| | - James A. Imlay
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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Anand A, Olson CA, Sastry AV, Patel A, Szubin R, Yang L, Feist AM, Palsson BO. Restoration of fitness lost due to dysregulation of the pyruvate dehydrogenase complex is triggered by ribosomal binding site modifications. Cell Rep 2021; 35:108961. [PMID: 33826886 PMCID: PMC8489512 DOI: 10.1016/j.celrep.2021.108961] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 02/22/2021] [Accepted: 03/16/2021] [Indexed: 11/23/2022] Open
Abstract
Pyruvate dehydrogenase complex (PDC) functions as the main determinant of the respiro-fermentative balance because it converts pyruvate to acetyl-coenzyme A (CoA), which then enters the TCA (tricarboxylic acid cycle). PDC is repressed by the pyruvate dehydrogenase complex regulator (PdhR) in Escherichia coli. The deletion of the pdhR gene compromises fitness in aerobic environments. We evolve the E. coli pdhR deletion strain to examine its achievable growth rate and the underlying adaptive strategies. We find that (1) optimal proteome allocation to PDC is critical in achieving optimal growth rate; (2) expression of PDC in evolved strains is reduced through mutations in the Shine-Dalgarno sequence; (3) rewiring of the TCA flux and increased reactive oxygen species (ROS) defense occur in the evolved strains; and (4) the evolved strains adapt to an efficient biomass yield. Together, these results show how adaptation can find alternative regulatory mechanisms for a key cellular process if the primary regulatory mode fails.
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Affiliation(s)
- Amitesh Anand
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Connor A Olson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anand V Sastry
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Arjun Patel
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Richard Szubin
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Laurence Yang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA; Department of Chemical Engineering, Queen's University, Kingston, ON, Canada
| | - Adam M Feist
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kongens, Lyngby, Denmark
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA; Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kongens, Lyngby, Denmark.
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Zhou H, Gao S, Zeng W, Zhou J. Improving bioconversion of eugenol to coniferyl alcohol by constitutive promoters in Escherichia coli. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.107953] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Shaeer A, Aslam M, Rashid N. Structural and functional analyses of a novel manganese-catalase from Bacillus subtilis R5. Int J Biol Macromol 2021; 180:222-233. [PMID: 33737179 DOI: 10.1016/j.ijbiomac.2021.03.074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/13/2021] [Accepted: 03/13/2021] [Indexed: 12/24/2022]
Abstract
Catalases catalyze the decomposition of hydrogen peroxide into water and oxygen. Limited reports are available on characterization of manganese-catalases. We describe here molecular cloning and expression in Escherichia coli of a putative manganese-catalase gene from mesophilic bacterium, Bacillus subtilis R5. The gene product, CatBsu, produced as a soluble protein, was purified to apparent homogeneity and biochemically characterized. The absorption spectra and nonsignificant inhibition by sodium azide indicated that it is a manganese-catalase. The protein was in homohexameric form in solution, with a subunit molecular weight of 30 kDa, containing ~2 Mn2+ and ~1 Ca2+ per subunit. CatBsu showed highest activity at pH 8.0 and 55 °C. It was found to be highly active with a specific activity of 25,290 μmol min-1 mg-1 and apparent Km and kcat values of 98 mM and 1.27 × 104 s-1 subunit-1, respectively. Although from a mesophilic source, it exhibited a half-life of 2 h at 80 °C. Furthermore, the active site and metal binding residues in CatBsu were predicted by homology modelling and molecular docking. To the best of our knowledge, this is the first characterization of a manganese-catalase from genus Bacillus.
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Affiliation(s)
- Abeera Shaeer
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan
| | - Mehwish Aslam
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan
| | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore 54590, Pakistan.
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Redox Active Antimicrobial Peptides in Controlling Growth of Microorganisms at Body Barriers. Antioxidants (Basel) 2021; 10:antiox10030446. [PMID: 33805777 PMCID: PMC7998263 DOI: 10.3390/antiox10030446] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/05/2021] [Accepted: 03/09/2021] [Indexed: 01/14/2023] Open
Abstract
Epithelia in the skin, gut and other environmentally exposed organs display a variety of mechanisms to control microbial communities and limit potential pathogenic microbial invasion. Naturally occurring antimicrobial proteins/peptides and their synthetic derivatives (here collectively referred to as AMPs) reinforce the antimicrobial barrier function of epithelial cells. Understanding how these AMPs are functionally regulated may be important for new therapeutic approaches to combat microbial infections. Some AMPs are subject to redox-dependent regulation. This review aims to: (i) explore cysteine-based redox active AMPs in skin and intestine; (ii) discuss casual links between various redox environments of these barrier tissues and the ability of AMPs to control cutaneous and intestinal microbes; (iii) highlight how bacteria, through intrinsic mechanisms, can influence the bactericidal potential of redox-sensitive AMPs.
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Kirthika P, Senevirathne A, Jawalagatti V, Park S, Lee JH. Deletion of the lon gene augments expression of Salmonella Pathogenicity Island (SPI)-1 and metal ion uptake genes leading to the accumulation of bactericidal hydroxyl radicals and host pro-inflammatory cytokine-mediated rapid intracellular clearance. Gut Microbes 2020; 11:1695-1712. [PMID: 32567462 PMCID: PMC7524146 DOI: 10.1080/19490976.2020.1777923] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In the present study, we characterized the involvement of Lon protease in bacterial virulence and intracellular survival in Salmonella under abiotic stress conditions resembling the conditions of a natural infection. Wild type (JOL401) and the lon mutant (JOL909) Salmonella Typhimurium were exposed to low temperature, pH, osmotic, and oxidative stress conditions and changes in gene expression profiles related to virulence and metal ion uptake were investigated. Expression of candidate genes invF and hilC of Salmonella Pathogenicity Island (SPI)-1 and sifA and sseJ of SPI-2 revealed that Lon protease controls SPI-1 genes and not SPI-2 genes under all stress conditions tested. The lon mutant exhibited increased accumulation of hydroxyl (OH·) ions that lead to cell damage due to oxidative stress. This oxidative damage can also be linked to an unregulated influx of iron due to the upregulation of ion channel genes such as fepA in the lon mutant. The deletion of lon from the Salmonella genome causes oxidative damage and increased expression of virulence genes. It also prompts the secretion of host pro-inflammatory cytokines leading to early clearance of the bacteria from host cells. We conclude that poor bacterial recovery from mice infected with the lon mutant is a result of disrupted bacterial intracellular equilibrium and rapid activation of cytokine expression leading to bacterial lysis.
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Affiliation(s)
- Perumalraja Kirthika
- College of Veterinary Medicine, Jeonbuk National University, Iksan, Republic of Korea
| | - Amal Senevirathne
- College of Veterinary Medicine, Jeonbuk National University, Iksan, Republic of Korea
| | | | - SungWoo Park
- College of Veterinary Medicine, Jeonbuk National University, Iksan, Republic of Korea
| | - John Hwa Lee
- College of Veterinary Medicine, Jeonbuk National University, Iksan, Republic of Korea,CONTACT John Hwa Lee College of Veterinary Medicine, Jeonbuk National University, 54596, Republic of Korea
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Khademian M, Imlay JA. Do reactive oxygen species or does oxygen itself confer obligate anaerobiosis? The case of Bacteroides thetaiotaomicron. Mol Microbiol 2020; 114:333-347. [PMID: 32301184 DOI: 10.1111/mmi.14516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023]
Abstract
Bacteroides thetaiotaomicron was examined to determine whether its obligate anaerobiosis is imposed by endogenous reactive oxygen species or by molecular oxygen itself. Previous analyses established that aerated B. thetaiotaomicron loses some enzyme activities due to a high rate of endogenous superoxide formation. However, the present study establishes that another key step in central metabolism is poisoned by molecular oxygen itself. Pyruvate dissimilation was shown to depend upon two enzymes, pyruvate:formate lyase (PFL) and pyruvate:ferredoxin oxidoreductase (PFOR), that lose activity upon aeration. PFL is a glycyl-radical enzyme whose vulnerability to oxygen is already understood. The rate of PFOR damage was unaffected by the level of superoxide or peroxide, showing that molecular oxygen itself is the culprit. The cell cannot repair PFOR, which amplifies the impact of damage. The rates of PFOR and fumarase inactivation are similar, suggesting that superoxide dismutase is calibrated so the oxygen- and superoxide-sensitive enzymes are equally sensitive to aeration. The physiological purpose of PFL and PFOR is to degrade pyruvate without disrupting the redox balance, and they do so using catalytic mechanisms that are intrinsically vulnerable to oxygen. In this way, the anaerobic excellence and oxygen sensitivity of B. thetaiotaomicron are two sides of the same coin.
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Affiliation(s)
- Maryam Khademian
- Department of Microbiology, University of Illinois, Urbana, IL, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, USA
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Ciemniecki JA, Newman DK. The Potential for Redox-Active Metabolites To Enhance or Unlock Anaerobic Survival Metabolisms in Aerobes. J Bacteriol 2020; 202:e00797-19. [PMID: 32071098 PMCID: PMC7221258 DOI: 10.1128/jb.00797-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Classifying microorganisms as "obligate" aerobes has colloquially implied death without air, leading to the erroneous assumption that, without oxygen, they are unable to survive. However, over the past few decades, more than a few obligate aerobes have been found to possess anaerobic energy conservation strategies that sustain metabolic activity in the absence of growth or at very low growth rates. Similarly, studies emphasizing the aerobic prowess of certain facultative aerobes have sometimes led to underrecognition of their anaerobic capabilities. Yet an inescapable consequence of the affinity both obligate and facultative aerobes have for oxygen is that the metabolism of these organisms may drive this substrate to scarcity, making anoxic survival an essential skill. To illustrate this, we highlight the importance of anaerobic survival strategies for Pseudomonas aeruginosa and Streptomyces coelicolor, representative facultative and obligate aerobes, respectively. Included among these strategies, we describe a role for redox-active secondary metabolites (RAMs), such as phenazines made by P. aeruginosa, in enhancing substrate-level phosphorylation. Importantly, RAMs are made by diverse bacteria, often during stationary phase in the absence of oxygen, and can sustain anoxic survival. We present a hypothesis for how RAMs may enhance or even unlock energy conservation pathways that facilitate the anaerobic survival of both RAM producers and nonproducers.
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Affiliation(s)
- John A Ciemniecki
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
| | - Dianne K Newman
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California, USA
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA
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48
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Chen Z, Li Z, Li F, Wang N, Gao XD. Characterization of alditol oxidase from Streptomyces coelicolor and its application in the production of rare sugars. Bioorg Med Chem 2020; 28:115464. [DOI: 10.1016/j.bmc.2020.115464] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 02/21/2020] [Accepted: 03/23/2020] [Indexed: 01/06/2023]
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Mosteo R, Varon Lopez A, Muzard D, Benitez N, Giannakis S, Pulgarin C. Visible light plays a significant role during bacterial inactivation by the photo-fenton process, even at sub-critical light intensities. WATER RESEARCH 2020; 174:115636. [PMID: 32109753 DOI: 10.1016/j.watres.2020.115636] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/15/2020] [Accepted: 02/18/2020] [Indexed: 06/10/2023]
Abstract
The aim of this research is to clarify the contribution of sunlight wavelengths, irradiance and Fe2+/H2O2 during bacterial disinfection by the photo-Fenton process in clear surface waters. We considered different solar spectrum distributions (visible, UVA-Visible), sub-critical irradiances (0-400 W/m2), focusing on the action modes of E. coli inactivation by the constituents involved in the composite process, at low μM reactants concentration (Fe2+/H2O2) in in ultrapure (MQ) water. We report that solar disinfection improved with Fenton reagents (photo-Fenton process) is a reality from very low light irradiance values (200 W/m2), and made possible even without the presence of UVA radiation, even when using low quantities of the Fenton reagents (0.5 mg/L Fe2+, 5 mg/L H2O2). Under light exposure, H2O2 was found to augment the intracellular Fenton process and Fe2+ to initiate further, distinct oxidative actions. Finally, validation was performed in Lake Geneva water over a wider irradiance range, where the photo-Fenton process was found to be reagent-dependent in low irradiance, shifting to light-driven in the higher values.
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Affiliation(s)
- Rosa Mosteo
- Department of Chemical Engineering and Environmental Technology, Environmental Sciences Institute (IUCA), University of Zaragoza, Zaragoza, Spain; School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Angelica Varon Lopez
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland; Universidad del Valle, Departamento de Química, Grupo de Investigación en Procesos Avanzados de Oxidación (GAOX), A.A. 25360 Cali, Colombia
| | - David Muzard
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland
| | - Norberto Benitez
- Universidad del Valle, Departamento de Química, Grupo de Investigación en Procesos Avanzados de Oxidación (GAOX), A.A. 25360 Cali, Colombia
| | - Stefanos Giannakis
- Universidad Politécnica de Madrid (UPM), E.T.S. Ingenieros de Caminos, Canales y Puertos, Departamento de Ingeniería Civil: Hidráulica, Energía y Medio Ambiente, Unidad docente Ingeniería Sanitaria, c/ Profesor Aranguren, s/n, ES-28040, Madrid, Spain.
| | - Cesar Pulgarin
- School of Basic Sciences (SB), Institute of Chemical Science and Engineering (ISIC), Group of Advanced Oxidation Processes (GPAO), École Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015, Lausanne, Switzerland.
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50
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Nicol MJ, Brubaker TR, Honish BJ, Simmons AN, Kazemi A, Geissel MA, Whalen CT, Siedlecki CA, Bilén SG, Knecht SD, Kirimanjeswara GS. Antibacterial effects of low-temperature plasma generated by atmospheric-pressure plasma jet are mediated by reactive oxygen species. Sci Rep 2020; 10:3066. [PMID: 32080228 PMCID: PMC7033188 DOI: 10.1038/s41598-020-59652-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/13/2019] [Indexed: 12/05/2022] Open
Abstract
Emergence and spread of antibiotic resistance calls for development of non-chemical treatment options for bacterial infections. Plasma medicine applies low-temperature plasma (LTP) physics to address biomedical problems such as wound healing and tumor suppression. LTP has also been used for surface disinfection. However, there is still much to be learned regarding the effectiveness of LTP on bacteria in suspension in liquids, and especially on porous surfaces. We investigated the efficacy of LTP treatments against bacteria using an atmospheric-pressure plasma jet and show that LTP treatments have the ability to inhibit both gram-positive (S. aureus) and gram-negative (E. coli) bacteria on solid and porous surfaces. Additionally, both direct LTP treatment and plasma-activated media were effective against the bacteria suspended in liquid culture. Our data indicate that reactive oxygen species are the key mediators of the bactericidal effects of LTP and hydrogen peroxide is necessary but not sufficient for antibacterial effects. In addition, our data suggests that bacteria exposed to LTP do not develop resistance to further treatment with LTP. These findings suggest that this novel atmospheric-pressure plasma jet could be used as a potential alternative to antibiotic treatments in vivo.
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Affiliation(s)
- McKayla J Nicol
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
- Pathobiology Graduate Program, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Timothy R Brubaker
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Brian J Honish
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Alyssa N Simmons
- Department of Mechanical Engineering and Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Ali Kazemi
- Department of Mechanical Engineering and Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Madison A Geissel
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Connor T Whalen
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | | | - Sven G Bilén
- School of Engineering Design, Technology, and Professional Programs, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Sean D Knecht
- School of Engineering Design, Technology, and Professional Programs, The Pennsylvania State University, University Park, PA, 16802, USA.
| | - Girish S Kirimanjeswara
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
- The Center for Molecular Immunology and Infectious Disease, The Pennsylvania State University, University Park, PA, 16802, USA.
- The Center for Infectious Disease Dynamics, The Pennsylvania State University, University Park, PA, 16802, USA.
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