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Berscheid A, Straetener J, Schilling NA, Ruppelt D, Konnerth MC, Schittek B, Krismer B, Peschel A, Steinem C, Grond S, Brötz-Oesterhelt H. The microbiome-derived antibacterial lugdunin acts as a cation ionophore in synergy with host peptides. mBio 2024; 15:e0057824. [PMID: 39133006 PMCID: PMC11389392 DOI: 10.1128/mbio.00578-24] [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: 03/15/2024] [Accepted: 07/02/2024] [Indexed: 08/13/2024] Open
Abstract
Lugdunin is a microbiome-derived antibacterial agent with good activity against Gram-positive pathogens in vitro and in animal models of nose colonization and skin infection. We have previously shown that lugdunin depletes bacterial energy resources by dissipating the membrane potential of Staphylococcus aureus. Here, we explored the mechanism of action of lugdunin in more detail and show that lugdunin quickly depolarizes cytoplasmic membranes of different bacterial species and acidifies the cytoplasm of S. aureus within minutes due to protonophore activity. Varying the salt species and concentrations in buffers revealed that not only protons are transported, and we demonstrate the binding of the monovalent cations K+, Na+, and Li+ to lugdunin. By comparing known ionophores with various ion transport mechanisms, we conclude that the ion selectivity of lugdunin largely resembles that of 15-mer linear peptide gramicidin A. Direct interference with the main bacterial metabolic pathways including DNA, RNA, protein, and cell wall biosyntheses can be excluded. The previously observed synergism of lugdunin with dermcidin-derived peptides such as DCD-1 in killing S. aureus is mechanistically based on potentiated membrane depolarization. We also found that lugdunin was active against certain eukaryotic cells, however strongly depending on the cell line and growth conditions. While adherent lung epithelial cell lines were almost unaffected, more sensitive cells showed dissipation of the mitochondrial membrane potential. Lugdunin seems specifically adapted to its natural environment in the respiratory tract. The ionophore mechanism is refractory to resistance development and benefits from synergy with host-derived antimicrobial peptides. IMPORTANCE The vast majority of antimicrobial peptides produced by members of the microbiome target the bacterial cell envelope by many different mechanisms. These compounds and their producers have evolved side-by-side with their host and were constantly challenged by the host's immune system. These molecules are optimized to be well tolerated at their physiological site of production, and their modes of action have proven efficient in vivo. Imbalancing the cellular ion homeostasis is a prominent mechanism among antibacterial natural products. For instance, over 120 naturally occurring polyether ionophores are known to date, and antimicrobial peptides with ionophore activity have also been detected in microbiomes. In this study, we elucidated the mechanism underlying the membrane potential-dissipating activity of the thiazolidine-containing cycloheptapeptide lugdunin, the first member of the fibupeptides discovered in a commensal bacterium from the human nose, which is a promising future probiotic candidate that is not prone to resistance development.
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Affiliation(s)
- Anne Berscheid
- Interfaculty Institute of Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany
- Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Jan Straetener
- Interfaculty Institute of Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany
| | - Nadine A Schilling
- Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany
| | - Dominik Ruppelt
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Göttingen, Germany
| | - Martin C Konnerth
- Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany
| | - Birgit Schittek
- Department of Dermatology, Division of Dermatooncology, University of Tübingen, Tübingen, Germany
| | - Bernhard Krismer
- Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Infection Biology, University of Tübingen, Tübingen, Germany
- Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany
| | - Andreas Peschel
- Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine, Infection Biology, University of Tübingen, Tübingen, Germany
- Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany
| | - Claudia Steinem
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Göttingen, Germany
- Max-Planck-Institute for Dynamics and Self Organization, Göttingen, Germany
| | - Stephanie Grond
- Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany
- Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany
| | - Heike Brötz-Oesterhelt
- Interfaculty Institute of Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany
- Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
- Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany
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Li F, Xu T, Fang D, Wang Z, Liu Y. Inosine reverses multidrug resistance in Gram-negative bacteria carrying mobilized RND-type efflux pump gene cluster tmexCD-toprJ. mSystems 2024:e0079724. [PMID: 39254032 DOI: 10.1128/msystems.00797-24] [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: 06/11/2024] [Accepted: 08/19/2024] [Indexed: 09/11/2024] Open
Abstract
Antimicrobial resistance is rapidly increasing worldwide, highlighting the urgent need for pharmaceutical and nonpharmaceutical interventions to tackle different-to-treat bacterial infections. Tigecycline, a semi-synthesis glycylcycline for parenteral administration, is widely recognized as one of the few effective therapies available against pan-drug resistant Gram-negative pathogens. Regrettably, the efficacy of multiple drugs, including tigecycline, is currently being undermined due to the emergence of a recently discovered mobilized resistance-nodulation-division-type efflux pump gene cluster tmexCD1-toprJ1. Herein, by employing untargeted metabolomic approaches, we reveal that the expression of tmexCD1-toprJ1 disrupts bacterial purine metabolism, with inosine being identified as a crucial biomarker. Notably, the supplementation of inosine effectively reverses tigecycline resistance in tmexCD1-toprJ1-positive bacteria. Mechanistically, exogenous inosine enhanced bacterial proton motive force, which promotes the uptake of tigecycline. Furthermore, inosine enhances succinate biosynthesis by stimulating the tricarboxylic acid cycle. Succinate interacts with the two-component system EnvZ/OmpR and upregulates OmpK 36, thereby promoting the influx of tigecycline. These actions collectively lead to the increased intracellular accumulation of tigecycline. Overall, our study offers a distinct combinational strategy to manage infections caused by tmexCD-toprJ-positive bacteria. IMPORTANCE TMexCD1-TOprJ1, a mobilized resistance-nodulation-division-type efflux pump, confers phenotypic resistance to multiple classes of antibiotics. Nowadays, tmexCD-toprJ has disseminated among diverse species of clinical pathogens, exacerbating the need for novel anti-infective strategies. In this study, we report that tmexCD1-toprJ1-negative and -positive bacteria exhibit significantly different metabolic flux and characteristics, especially in purine metabolism. Intriguingly, the addition of inosine, a purine metabolite, effectively restores the antibacterial activity of tigecycline by promoting antibiotic uptake. Our findings highlight the correlation between bacterial mechanism and antibiotic resistance, and offer a distinct approach to overcome tmexCD-toprJ-mediated multidrug resistance.
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Affiliation(s)
- Fulei Li
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Tianqi Xu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Dan Fang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Zhiqiang Wang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Yuan Liu
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, the Ministry of Education of China, Yangzhou University, Yangzhou, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, China
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3
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Biquet-Bisquert A, Carrio B, Meyer N, Fernandes TFD, Abkarian M, Seduk F, Magalon A, Nord AL, Pedaci F. Spatiotemporal dynamics of the proton motive force on single bacterial cells. SCIENCE ADVANCES 2024; 10:eadl5849. [PMID: 38781330 PMCID: PMC11114223 DOI: 10.1126/sciadv.adl5849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 04/18/2024] [Indexed: 05/25/2024]
Abstract
Electrochemical gradients across biological membranes are vital for cellular bioenergetics. In bacteria, the proton motive force (PMF) drives essential processes like adenosine triphosphate production and motility. Traditionally viewed as temporally and spatially stable, recent research reveals a dynamic PMF behavior at both single-cell and community levels. Moreover, the observed lateral segregation of respiratory complexes could suggest a spatial heterogeneity of the PMF. Using a light-activated proton pump and detecting the activity of the bacterial flagellar motor, we perturb and probe the PMF of single cells. Spatially homogeneous PMF perturbations reveal millisecond-scale temporal dynamics and an asymmetrical capacitive response. Localized perturbations show a rapid lateral PMF homogenization, faster than proton diffusion, akin to the electrotonic potential spread observed in passive neurons, explained by cable theory. These observations imply a global coupling between PMF sources and consumers along the membrane, precluding sustained PMF spatial heterogeneity but allowing for rapid temporal changes.
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Affiliation(s)
- Anaïs Biquet-Bisquert
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
| | - Baptiste Carrio
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
| | - Nathan Meyer
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
| | - Thales F. D. Fernandes
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
| | - Manouk Abkarian
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
| | - Farida Seduk
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13402 Marseille, France
| | - Axel Magalon
- Aix Marseille Université, CNRS, Laboratoire de Chimie Bactérienne (UMR7283), IMM, IM2B, 13402 Marseille, France
| | - Ashley L. Nord
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
| | - Francesco Pedaci
- Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France
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Wang C, Ji Y, Huo X, Li X, Lu W, Zhang Z, Dong W, Wang X, Chen H, Tan C. Discovery of Salifungin as a Repurposed Antibiotic against Methicillin-Resistant Staphylococcus aureus with Limited Resistance Development. ACS Infect Dis 2024; 10:1576-1589. [PMID: 38581387 DOI: 10.1021/acsinfecdis.3c00611] [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] [Indexed: 04/08/2024]
Abstract
Exploring novel antimicrobial drugs and strategies has become essential to the fight MRSA-associated infections. Herein, we found that membrane-disrupted repurposed antibiotic salifungin had excellent bactericidal activity against MRSA, with limited development of drug resistance. Furthermore, adding salifungin effectively decreased the minimum inhibitory concentrations of clinical antibiotics against Staphylococcus aureus. Evaluations of the mechanism demonstrated that salifungin disrupted the level of H+ and K+ ions using hydrophilic and lipophilic groups to interact with bacterial membranes, causing the disruption of bacterial proton motive force followed by impacting on bacterial the function of the respiratory chain and adenosine 5'-triphosphate, thereby inhibiting phosphatidic acid biosynthesis. Moreover, salifungin also significantly inhibited the formation of bacterial biofilms and eliminated established bacterial biofilms by interfering with bacterial membrane potential and inhibiting biofilm-associated gene expression, which was even better than clinical antibiotics. Finally, salifungin exhibited efficacy comparable to or even better than that of vancomycin in the MRSA-infected animal models. In conclusion, these results indicate that salifungin can be a potential drug for treating MRSA-associated infections.
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Affiliation(s)
- Chenchen Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Yueyue Ji
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Xingyu Huo
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Xiaodan Li
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Wenjia Lu
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Zhaoran Zhang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Wenqi Dong
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
| | - Xiangru Wang
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
- Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430000, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan 430000, Hubei, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430000, Hubei, China
| | - Huanchun Chen
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
- Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430000, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan 430000, Hubei, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430000, Hubei, China
| | - Chen Tan
- National Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430000, Hubei, China
- Hubei Hongshan Laboratory, Wuhan 430000, Hubei, China
- Frontiers Science Center for Animal Breeding and Sustainable Production, Wuhan 430000, Hubei, China
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, Wuhan 430000, Hubei, China
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430000, Hubei, China
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5
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Gevorgyan H, Baghdasaryan L, Trchounian K. Regulation of metabolism and proton motive force generation during mixed carbon fermentation by an Escherichia coli strain lacking the F OF 1-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149034. [PMID: 38354879 DOI: 10.1016/j.bbabio.2024.149034] [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: 10/03/2023] [Revised: 01/15/2024] [Accepted: 02/09/2024] [Indexed: 02/16/2024]
Abstract
Proton FOF1-ATPase is the key enzyme in E. coli under fermentative conditions. In this study the role of E. coli proton ATPase in the μ and formation of metabolic pathways during the fermentation of mixture of glucose, glycerol and formate using the DK8 (lacking FOF1) mutant strain was investigated. It was shown that the contribution of FOF1-ATPase in the specific growth rate was ∼45 %. Formate was not taken up in the DK8 strain during the initial hours of the growth. The utilization rates of glucose and glycerol were unchanged in DK8, however, the production of succinate, lactate and ethanol was decreased causing a reduction of the redox state up to -450 mV. Moreover, the contribution of FOF1-ATPase in the interplay between H+ and H2 cycles was described depending on the bacterial growth phase and main utilizing substrate. Besides, the H2 production rate in the DK8 strain was decreased by ∼60 % at 20 h and was absent at 72 h. Δp was decreased from -157 ± 4.8 mV to -140 ± 4.2 mV at 20 h and from -195 ± 5.9 mV to -148 ± 4.4 mV at 72 h, compared to WT. Taken together it can be concluded that during fermentation of mixed carbon sources metabolic cross talk between FOF1-ATPase-TrkA-Hyd-Fdh-H is taking place for maintaining the cell energy balance via regulation proton motive force.
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Affiliation(s)
- Heghine Gevorgyan
- Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia; Scientific-Research Institute of Biology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia; Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 0025 Yerevan, Armenia
| | - Lilit Baghdasaryan
- Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia; Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 0025 Yerevan, Armenia
| | - Karen Trchounian
- Department of Biochemistry, Microbiology and Biotechnology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia; Scientific-Research Institute of Biology, Faculty of Biology, Yerevan State University, 0025 Yerevan, Armenia; Microbial Biotechnologies and Biofuel Innovation Center, Yerevan State University, 0025 Yerevan, Armenia.
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6
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Lin XQ, Liu ZZ, Zhou CK, Zhang L, Gao Y, Luo XY, Zhang JG, Chen W, Yang YJ. Trained immunity in recurrent Staphylococcus aureus infection promotes bacterial persistence. PLoS Pathog 2024; 20:e1011918. [PMID: 38241414 PMCID: PMC10798626 DOI: 10.1371/journal.ppat.1011918] [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: 10/03/2023] [Accepted: 12/20/2023] [Indexed: 01/21/2024] Open
Abstract
Bacterial persister cells, a sub-population of dormant phenotypic variants highly tolerant to antibiotics, present a significant challenge for infection control. Investigating the mechanisms of antibiotic persistence is crucial for developing effective treatment strategies. Here, we found a significant association between tolerance frequency and previous infection history in bovine mastitis. Previous S. aureus infection led to S. aureus tolerance to killing by rifampicin in subsequent infection in vivo and in vitro. Actually, the activation of trained immunity contributed to rifampicin persistence of S. aureus in secondary infection, where it reduced the effectiveness of antibiotic treatment and increased disease severity. Mechanically, we found that S. aureus persistence was mediated by the accumulation of fumarate provoked by trained immunity. Combination therapy with metformin and rifampicin promoted eradication of persisters and improved the severity of recurrent S. aureus infection. These findings provide mechanistic insight into the relationship between trained immunity and S. aureus persistence, while providing proof of concept that trained immunity is a therapeutic target in recurrent bacterial infections involving persistent pathogens.
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Affiliation(s)
- Xiao-Qi Lin
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Zhen-Zhen Liu
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Cheng-Kai Zhou
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Liang Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Yu Gao
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Xue-Yue Luo
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Jian-Gang Zhang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Wei Chen
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
| | - Yong-Jun Yang
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Jilin University, Changchun, People’s Republic of China
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7
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Lan X, Zhong J, Huang R, Liu Y, Ma X, Li X, Zhao D, Qing G, Zhang Y, Liu L, Wang J, Ma X, Luo T, Guo W, Wang Y, Li LL, Su YX, Liang XJ. Conformation Dependent Architectures of Assembled Antimicrobial Peptides with Enhanced Antimicrobial Ability. Adv Healthc Mater 2023; 12:e2301688. [PMID: 37540835 DOI: 10.1002/adhm.202301688] [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: 05/26/2023] [Revised: 07/19/2023] [Indexed: 08/06/2023]
Abstract
Antimicrobial peptides (AMPs) are a developing class of natural and synthetic oligopeptides with host defense mechanisms against a broad spectrum of microorganisms. With in-depth research on the structural conformations of AMPs, synthesis or modification of peptides has shown great potential in effectively obtaining new therapeutic agents with improved physicochemical and biological properties. Notably, AMPs with self-assembled properties have gradually become a hot research topic for various biomedical applications. Compared to monomeric peptides, these peptides can exist in diverse forms (e.g., nanoparticles, nanorods, and nanofibers) and possess several advantages, such as high stability, good biocompatibility, and potent biological functions, after forming aggregates under specific conditions. In particular, the stability and antibacterial property of these AMPs can be modulated by rationally regulating the peptide sequences to promote self-assembly, leading to the reconstruction of molecular structure and spatial orientation while introducing some peptide fragments into the scaffolds. In this work, four self-assembled AMPs are developed, and the relationship between their chemical structures and antibacterial activity is explored extensively through different experiments. Importantly, the evaluation of antibacterial performance in both in vitro and in vivo studies has provided a general guide for using self-assembled AMPs in subsequent treatments for combating bacterial infections.
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Affiliation(s)
- Xinmiao Lan
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, School of Pharmaceutical Science, Capital Medical University, Beijing, 100069, China
- Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, 999077, China
| | - Jie Zhong
- Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, 999077, China
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Regina Huang
- Discipline of Periodontology, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, 999077, China
| | - Yuhan Liu
- Department of Stomatology, Aviation General Hospital of China Medical University and Beijing Institute of Translational Medicine, Chinese Academy of Science, Beijing, 100012, China
| | - Xiaowei Ma
- National Center for Veterinary Drug Safety Evaluation, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xuan Li
- Discipline of Periodontology, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, 999077, China
| | - Dan Zhao
- Beijing Institute of Dental Research, Beijing Stomatological Hospital, Capital Medical University, Beijing, 100069, China
| | - Guangchao Qing
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
| | - Yuxuan Zhang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lu Liu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinjin Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xu Ma
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ting Luo
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
| | - Weisheng Guo
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
| | - Yuji Wang
- Beijing Area Major Laboratory of Peptide and Small Molecular Drugs, Engineering Research Center of Ministry of Education of China, Beijing Laboratory of Biomedical Materials, School of Pharmaceutical Science, Capital Medical University, Beijing, 100069, China
| | - Li-Li Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu-Xiong Su
- Discipline of Oral and Maxillofacial Surgery, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, 999077, China
| | - Xing-Jie Liang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Zhang N, Shan W, Gao L, Kou SH, Lu C, Yang H, Peng B, Tam KY, Lee LTO, Zheng J. Repurposing the Hedgehog pathway inhibitor, BMS-833923, as a phosphatidylglycerol-selective membrane-disruptive colistin adjuvant against ESKAPE pathogens. Int J Antimicrob Agents 2023; 62:106888. [PMID: 37328075 DOI: 10.1016/j.ijantimicag.2023.106888] [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: 03/18/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/18/2023]
Abstract
The rapid emergence and spread of multi-drug- or pan-drug-resistant bacterial pathogens, such as ESKAPE, pose a serious threat to global health. However, the development of novel antibiotics is hindered by difficulties in identifying new antibiotic targets and the rapid development of drug resistance. Drug repurposing is an effective alternative strategy for combating antibiotic resistance that both saves resources and extends the life of existing antibiotics in combination treatment regimens. Screening of a chemical compound library identified BMS-833923 (BMS), a smoothened antagonist that kills Gram-positive bacteria directly, and potentiates colistin to destroy various Gram-negative bacteria. BMS did not induce detectable antibiotic resistance in vitro, and showed effective activity against drug-resistant bacteria in vivo. Mechanistic studies revealed that BMS caused membrane disruption by targeting the membrane phospholipids phosphatidylglycerol and cardiolipin, promoting membrane dysfunction, metabolic disturbance, leakage of cellular components, and, ultimately, cell death. This study describes a potential strategy to enhance the efficacy of colistin and combat multi-drug-resistant ESKAPE pathogens.
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Affiliation(s)
- Nian Zhang
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Wenying Shan
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China; Cancer Centre, Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Liangliang Gao
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Si Hoi Kou
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Chang Lu
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China; Department of Laboratory Medicine, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
| | - Huilin Yang
- Department of Laboratory Medicine, Peking University Shenzhen Hospital, Shenzhen, Guangdong Province, China
| | - Bo Peng
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Kin Yip Tam
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China; Cancer Centre, Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Leo Tsz On Lee
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China; Cancer Centre, Faculty of Health Sciences, University of Macau, Taipa, Macau, China; Ministry of Education Frontiers Science Centre for Precision Oncology, University of Macau, Taipa, Macau, China; Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
| | - Jun Zheng
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China.
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9
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Wang X, van Beekveld RAM, Xu Y, Parmar A, Das S, Singh I, Breukink E. Analyzing mechanisms of action of antimicrobial peptides on bacterial membranes requires multiple complimentary assays and different bacterial strains. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184160. [PMID: 37100361 DOI: 10.1016/j.bbamem.2023.184160] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/21/2023] [Accepted: 04/03/2023] [Indexed: 04/28/2023]
Abstract
Antimicrobial peptides (AMPs) commonly target bacterial membranes and show broad-spectrum activity against microorganisms. In this research we used three AMPs (nisin, epilancin 15×, [R4L10]-teixobactin) and tested their membrane effects towards three strains (Staphylococcus simulans, Micrococcus flavus, Bacillus megaterium) in relation with their antibacterial activity. We describe fluorescence and luminescence-based assays to measure effects on membrane potential, intracellular pH, membrane permeabilization and intracellular ATP levels. The results show that our control peptide, nisin, performed mostly as expected in view of its targeted pore-forming activity, with fast killing kinetics that coincided with severe membrane permeabilization in all three strains. However, the mechanisms of action of both Epilancin 15× as well as [R4L10]-teixobactin appeared to depend strongly on the bacterium tested. In certain specific combinations of assay, peptide and bacterium, deviations from the general picture were observed. This was even the case for nisin, indicating the importance of using multiple assays and bacteria for mode of action studies to be able to draw proper conclusions on the mode of action of AMPs.
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Affiliation(s)
- Xiaoqi Wang
- Membrane Biochemistry and Biophysics, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Roy A M van Beekveld
- Membrane Biochemistry and Biophysics, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Yang Xu
- Membrane Biochemistry and Biophysics, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Anish Parmar
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX Liverpool, UK
| | - Sanjit Das
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool L7 8TX, UK; Antimicrobial Drug Discovery and Development, Department of Chemistry, The Robert Robinson Laboratories, University of Liverpool, L69 3BX Liverpool, UK
| | - Ishwar Singh
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology and Therapeutics, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, William Henry Duncan Building, 6 West Derby St, Liverpool L7 8TX, UK
| | - Eefjan Breukink
- Membrane Biochemistry and Biophysics, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, Netherlands; Zhejiang Provincial Key Laboratory of Food Microbiotechnology Research of China, the Zhejiang Gongshang University of China, Hangzhou, China.
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10
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Partipilo M, Claassens NJ, Slotboom DJ. A Hitchhiker's Guide to Supplying Enzymatic Reducing Power into Synthetic Cells. ACS Synth Biol 2023; 12:947-962. [PMID: 37052416 PMCID: PMC10127272 DOI: 10.1021/acssynbio.3c00070] [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: 01/31/2023] [Indexed: 04/14/2023]
Abstract
The construction from scratch of synthetic cells by assembling molecular building blocks is unquestionably an ambitious goal from a scientific and technological point of view. To realize functional life-like systems, minimal enzymatic modules are required to sustain the processes underlying the out-of-equilibrium thermodynamic status hallmarking life, including the essential supply of energy in the form of electrons. The nicotinamide cofactors NAD(H) and NADP(H) are the main electron carriers fueling reductive redox reactions of the metabolic network of living cells. One way to ensure the continuous availability of reduced nicotinamide cofactors in a synthetic cell is to build a minimal enzymatic module that can oxidize an external electron donor and reduce NAD(P)+. In the diverse world of metabolism there is a plethora of potential electron donors and enzymes known from living organisms to provide reducing power to NAD(P)+ coenzymes. This perspective proposes guidelines to enable the reduction of nicotinamide cofactors enclosed in phospholipid vesicles, while avoiding high burdens of or cross-talk with other encapsulated metabolic modules. By determining key requirements, such as the feasibility of the reaction and transport of the electron donor into the cell-like compartment, we select a shortlist of potentially suitable electron donors. We review the most convenient proteins for the use of these reducing agents, highlighting their main biochemical and structural features. Noting that specificity toward either NAD(H) or NADP(H) imposes a limitation common to most of the analyzed enzymes, we discuss the need for specific enzymes─transhydrogenases─to overcome this potential bottleneck.
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Affiliation(s)
- Michele Partipilo
- Department
of Biochemistry, Groningen Institute of Biomolecular Sciences &
Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Nico J. Claassens
- Laboratory
of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Dirk Jan Slotboom
- Department
of Biochemistry, Groningen Institute of Biomolecular Sciences &
Biotechnology, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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11
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Iu HTV, Fong PM, Yam HCB, Gao P, Yan B, Lai PM, Tang VYM, Li KH, Ma CW, Ng KHK, Sze KH, Yang D, Davies J, Kao RYT. Identification of a Small Molecule Compound Active against Antibiotic-Tolerant Staphylococcus aureus by Boosting ATP Synthesis. Int J Mol Sci 2023; 24:ijms24076242. [PMID: 37047217 PMCID: PMC10094146 DOI: 10.3390/ijms24076242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/15/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023] Open
Abstract
Antibiotic tolerance poses a threat to current antimicrobial armamentarium. Bacteria at a tolerant state survive in the presence of antibiotic treatment and account for persistence, relapse and recalcitrance of infections. Antibiotic treatment failure may occur due to antibiotic tolerance. Persistent infections are difficult to treat and are often associated with poor prognosis, imposing an enormous burden on the healthcare system. Effective strategies targeting antibiotic-tolerant bacteria are therefore highly warranted. In this study, small molecule compound SA-558 was identified to be effective against Staphylococcus aureus that are tolerant to being killed by conventional antibiotics. SA-558 mediated electroneutral transport across the membrane and led to increased ATP and ROS generation, resulting in a reduction of the population of antibiotic-tolerant bacteria. In a murine chronic infection model, of which vancomycin treatment failed, we demonstrated that SA-558 alone and in combination with vancomycin caused significant reduction of MRSA abundance. Our results indicate that SA-558 monotherapy or combinatorial therapy with vancomycin is an option for managing persistent S. aureus bacteremia infection and corroborate that bacterial metabolism is an important target for counteracting antibiotic tolerance.
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12
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Lee AH, Gupta R, Nguyen HN, Schmitz IR, Siegele DA, Lele PP. Heterogeneous Distribution of Proton Motive Force in Nonheritable Antibiotic Resistance. mBio 2023; 14:e0238422. [PMID: 36598258 PMCID: PMC9973297 DOI: 10.1128/mbio.02384-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 11/21/2022] [Indexed: 01/05/2023] Open
Abstract
Bacterial infections that are difficult to eradicate are often treated by sequentially exposing the bacteria to different antibiotics. Although effective, this approach can give rise to epigenetic or other phenomena that may help some cells adapt to and tolerate the antibiotics. Characteristics of such adapted cells are dormancy and low energy levels, which promote survival without lending long-term genetic resistance against antibiotics. In this work, we quantified motility in cells of Escherichia coli that adapted and survived sequential exposure to lethal doses of antibiotics. In populations that adapted to transcriptional inhibition by rifampicin, we observed that ~1 of 3 cells continued swimming for several hours in the presence of lethal concentrations of ampicillin. As motility is powered by proton motive force (PMF), our results suggested that many adapted cells retained a high PMF. Single-cell growth assays revealed that the high-PMF cells resuscitated and divided upon the removal of ampicillin, just as the low-PMF cells did, a behavior reminiscent of persister cells. Our results are consistent with the notion that cells in a clonal population may employ multiple different mechanisms to adapt to antibiotic stresses. Variable PMF is likely a feature of a bet-hedging strategy: a fraction of the adapted cell population lies dormant while the other fraction retains high PMF to be able to swim out of the deleterious environment. IMPORTANCE Bacterial cells with low PMF may survive antibiotic stress due to dormancy, which favors nonheritable resistance without genetic mutations or acquisitions. On the other hand, cells with high PMF are less tolerant, as PMF helps in the uptake of certain antibiotics. Here, we quantified flagellar motility as an indirect measure of the PMF in cells of Escherichia coli that had adapted to ampicillin. Despite the disadvantage of maintaining a high PMF in the presence of antibiotics, we observed high PMF in ~30% of the cells, as evidenced by their ability to swim rapidly for several hours. These and other results were consistent with the idea that antibiotic tolerance can arise via different mechanisms in a clonal population.
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Affiliation(s)
- Annie H. Lee
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA
| | - Rachit Gupta
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA
| | - Hong Nhi Nguyen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Isabella R. Schmitz
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA
| | - Deborah A. Siegele
- Department of Biology, Texas A&M University, College Station, Texas, USA
| | - Pushkar P. Lele
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA
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13
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Cui K, Yang W, Liu Z, Liu G, Li D, Sun Y, He G, Ma S, Cao Y, Jiang X, Chevalier S, Cornelis P, Wei Q, Wang Y. Chenodeoxycholic Acid-Amikacin Combination Enhances Eradication of Staphylococcus aureus. Microbiol Spectr 2023; 11:e0243022. [PMID: 36625660 PMCID: PMC9927322 DOI: 10.1128/spectrum.02430-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 12/07/2022] [Indexed: 01/11/2023] Open
Abstract
The rise of antibiotic resistance and dearth of novel antibiotics have posed a serious health crisis worldwide. In this study, we screened a combination of antibiotics and nonantibiotics providing a viable strategy to solve this issue by broadening the antimicrobial spectrum. We found that chenodeoxycholic acid (CDCA), a cholic acid derivative of the traditional Chinese medicine (TCM) Tanreqing (TRQ), synergizes with amikacin against Staphylococcus aureus in vitro, and this synergistic killing was effective against diverse methicillin-resistant S. aureus (MRSA) variants, including small-colony variants (SCVs), biofilm strains, and persisters. The CDCA-amikacin combination protects a mouse model from S. aureus infections. Mechanistically, CDCA increases the uptake of aminoglycosides in a proton motive force-dependent manner by dissipating the chemical potential and potentiates reactive oxygen species (ROS) generation by inhibiting superoxide dismutase activity. This work highlights the potential use of TCM components in treating S. aureus-associated infections and extend the use of aminoglycosides in eradicating Gram-positive pathogens. IMPORTANCE Multidrug resistance (MDR) is spreading globally with increasing speed. The search for new antibiotics is one of the key strategies in the fight against MDR. Antibiotic resistance breakers that may or may not have direct antibacterial action and can either be coadministered or conjugated with other antibiotics are being studied. To better expand the antibacterial spectrum of certain antibiotics, we identified one component from a traditional Chinese medicine, Tanreqing (TRQ), that increased the activity of aminoglycosides. We found that this so-called agent, chenodeoxycholic acid (CDCA), sensitizes Staphylococcus aureus to aminoglycoside killing and protects a mouse model from S. aureus infections. CDCA increases the uptake of aminoglycosides in a proton motive force-dependent manner by dissipating the chemical potential and potentiates ROS generation by inhibiting superoxide dismutase activity in S. aureus. Our work highlights the potential use of TCM or its effective components, such as CDCA, in treating antibiotic resistance-associated infections.
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Affiliation(s)
- Kaiyu Cui
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Weifeng Yang
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhiyuan Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Guijian Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Dongying Li
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yanan Sun
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Gaiying He
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Shuhua Ma
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yu Cao
- Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xuefan Jiang
- Beijing University of Chinese Medicine, Beijing, China
| | - Sylvie Chevalier
- Normandy University, University of Rouen Normandy, Laboratory of Microbiology Signals and Microenvironment, Evreux, France
| | - Pierre Cornelis
- Normandy University, University of Rouen Normandy, Laboratory of Microbiology Signals and Microenvironment, Evreux, France
| | - Qing Wei
- Nanchang Institute of Technology, Nanchang, Jiangxi, China
| | - Yi Wang
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing, China
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14
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Guo Y, Xiang Y, Liu G, Chen Y, Liu Y, Song M, Li Y, Shi J, Hu L, Yin Y, Cai Y, Jiang G. "Trojan Horse" Type Internalization Increases the Bioavailability of Mercury Sulfide Nanoparticles and Methylation after Intracellular Dissolution. ACS NANO 2023; 17:1925-1934. [PMID: 36688800 DOI: 10.1021/acsnano.2c05657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Mercury sulfide nanoparticles (HgSNP), as natural metal-containing nanoparticles, are the dominant Hg species in anoxic zones. Although the microbial Hg methylation of HgSNP has been previously reported, the importance of this process in Hg methylation has yet to be clarified due to the lack of knowledge on the internalization and transformation of HgSNP. Here, we investigated the internalization and transformation of HgSNP in microbial methylator Geobacter sulfurreducens PCA through total Hg analysis and different Hg species quantification in medium and cytoplasm. We found that the microbial uptake of HgSNP, via a passive diffusion pathway, was significantly higher than that of the Hg2+-dissolved organic matter (Hg2+-DOM) complex. Internalized HgSNP were dissolved to Hg2+ in cytoplasm with a maximal dissolution of 41%, suggesting a "Trojan horse" mechanism. The intracellular Hg2+ from HgSNP exposure at the initial stage (8 h) was higher than that in Hg2+-DOM group, which led to higher methylation of HgSNP. Furthermore, no differences in methylmercury (MeHg) production from HgSNP were observed between the hgcAB gene knockout (ΔhgcAB) and wild-type strains, suggesting that HgSNP methylation may occur through HgcAB-independent pathways. Considering the possibility of a broad range of hgcAB-lacking microbes serving as methylators for HgSNP and the ubiquity of HgSNP in anoxic environments, this study highlights the importance of HgSNP internalization and methylation in MeHg production and demonstrates the necessity of understanding the assimilation and transformation of nutrient and toxic metal nanoparticles in general.
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Affiliation(s)
- Yingying Guo
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
| | - Yuping Xiang
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
| | - Guangliang Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Ying Chen
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanwei Liu
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
| | - Maoyong Song
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
| | - Yanbin Li
- Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China
| | - Jianbo Shi
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
| | - Ligang Hu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
| | - Yongguang Yin
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- School of Environment, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| | - Yong Cai
- Laboratory of Environmental Nanotechnology and Health Effect, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Guibin Jiang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 10085, China
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15
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Mahmoudi P, Akbarpour MR, Lakeh HB, Jing F, Hadidi MR, Akhavan B. Antibacterial Ti-Cu implants: A critical review on mechanisms of action. Mater Today Bio 2022; 17:100447. [PMID: 36278144 PMCID: PMC9579810 DOI: 10.1016/j.mtbio.2022.100447] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/06/2022] Open
Abstract
Titanium (Ti) has been widely used for manufacturing of bone implants because of its mechanical properties, biological compatibility, and favorable corrosion resistance in biological environments. However, Ti implants are prone to infection (peri-implantitis) by bacteria which in extreme cases necessitate painful and costly revision surgeries. An emerging, viable solution for this problem is to use copper (Cu) as an antibacterial agent in the alloying system of Ti. The addition of copper provides excellent antibacterial activities, but the underpinning mechanisms are still obscure. This review sheds light on such mechanisms and reviews how incorporation of Cu can render Ti-Cu implants with antibacterial activity. The review first discusses the fundamentals of interactions between bacteria and implanted surfaces followed by an overview of the most common engineering strategies utilized to endow an implant with antibacterial activity. The underlying mechanisms for antibacterial activity of Ti-Cu implants are then discussed in detail. Special attention is paid to contact killing mechanisms because the misinterpretation of this mechanism is the root of discrepancies in the literature.
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Affiliation(s)
- Pezhman Mahmoudi
- Department of Materials Science and Engineering, Sharif University of Technology, Tehran, 11365-9466, Iran
| | - Mohammad Reza Akbarpour
- Department of Materials Engineering, University of Maragheh, Maragheh, P.O. Box 55136-553, Iran
| | | | - Fengjuan Jing
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Mohammad Reza Hadidi
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Behnam Akhavan
- School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
- Hunter Medical Research Institute (HMRI), Precision Medicine Research Program, New Lambton Heights, NSW, 2305, Australia
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16
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Lu Y, Yang L, Zhang W, Li J, Peng X, Qin Z, Zeng Z, Zeng D. Pharmacokinetics and pharmacodynamics of isopropoxy benzene guanidine against Clostridium perfringens in an intestinal infection model. Front Vet Sci 2022; 9:1004248. [PMID: 36246309 PMCID: PMC9557049 DOI: 10.3389/fvets.2022.1004248] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/15/2022] [Indexed: 11/24/2022] Open
Abstract
This study aimed to evaluate the antibacterial activity of isopropoxy benzene guanidine (IBG) against C. perfringens based on pharmacokinetics/pharmacodynamics (PK/PD) modeling in broilers. The PK parameters of IBG in the plasma and ileal content of C. perfringens-infected broilers following oral administration at 2, 30, and 60 mg/kg body weight were investigated. in vivo PD studies were conducted over oral administration ranging from 2 to 60 mg/kg and repeated every 12 h for 3 days. The inhibitory Imax model was used for PK/PD modeling. Results showed that the MIC of IBG against C. perfringens was 0.5–32 mg/L. After oral administration of IBG, the peak concentration (Cmax), maximum concentration time (Tmax), and area under the concentration-time curve (AUC) in ileal content of broilers were 10.97–1,036.64 mg/L, 2.39–4.27 h, and 38.31–4,266.77 mg·h/L, respectively. After integrating the PK and PD data, the AUC0 − 24h/MIC ratios needed for the bacteriostasis, bactericidal activity, and bacterial eradication were 4.00, 240.74, and 476.98 h, respectively. For dosage calculation, a dosage regimen of 12.98 mg/kg repeated every 12 h for 3 days was be therapeutically effective in broilers against C. perfringens with MIC ≤ 2 mg/L. In addition, IBG showed potent activity against C. perfringens, which may be responsible for cell membrane destruction. These results can facilitate the evaluation of the use of IBG in the treatment of intestinal diseases in broilers caused by C. perfringens.
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Affiliation(s)
- Yixing Lu
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Liuye Yang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Wanying Zhang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Jie Li
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Xianfeng Peng
- Guangzhou Insighter Biotechnology Co., Ltd., Guangzhou, China
| | - Zonghua Qin
- Guangzhou Insighter Biotechnology Co., Ltd., Guangzhou, China
| | - Zhenling Zeng
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- *Correspondence: Zhenling Zeng
| | - Dongping Zeng
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- Dongping Zeng
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Płocińska R, Wasik K, Płociński P, Lechowicz E, Antczak M, Błaszczyk E, Dziadek B, Słomka M, Rumijowska-Galewicz A, Dziadek J. The Orphan Response Regulator Rv3143 Modulates the Activity of the NADH Dehydrogenase Complex (Nuo) in Mycobacterium tuberculosis via Protein–Protein Interactions. Front Cell Infect Microbiol 2022; 12:909507. [PMID: 35837472 PMCID: PMC9274095 DOI: 10.3389/fcimb.2022.909507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Two-component signal transduction systems enable mycobacterial cells to quickly adapt and adequately respond to adverse environmental conditions encountered at various stages of host infection. We attempted to determine the role of the Rv3143 “orphan” response regulator in the physiology of Mycobacterium tuberculosis and its orthologue Msmeg_2064 in Mycobacterium smegmatis. We identified the Rv3143 protein as an interaction partner for NuoD, a member of the type I NADH dehydrogenase complex involved in oxidative phosphorylation. The mutants Δrv3143 and Δmsmeg_2064 were engineered in M. tuberculosis and M. smegmatis cells, respectively. The Δmsmeg_2064 strain exhibited a significant reduction in growth and viability in the presence of reactive nitrogen species. The Rv3143-deficient strain was sensitive to valinomycin, which is known to reduce the electrochemical potential of the cell and overexpressed genes required for nitrate respiration. An increased level of reduction of the 2,3,5-triphenyltetrazolium chloride (TTC) electron acceptor in Δrv3143 and Δmsmeg_2064 cells was also evident. The silencing of ndh expression using CRISPRi/dCas9 affected cell survival under limited oxygen conditions. Oxygen consumption during entry to hypoxia was most severely affected in the double-mutant Δmsmeg_2064 ndhCRISPRi/dCas9. We propose that the regulatory protein Rv3143 is a component of the Nuo complex and modulates its activity.
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Affiliation(s)
- Renata Płocińska
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
| | - Karolina Wasik
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
| | - Przemysław Płociński
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
- Department of Immunology and Infectious Biology, Faculty of Biology and Environmental Protection, University of Łódz, Łódź, Poland
| | - Ewelina Lechowicz
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
| | - Magdalena Antczak
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
| | - Ewelina Błaszczyk
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
| | - Bożena Dziadek
- Department of Molecular Microbiology, Faculty of Biology and Environmental Protection, University of Łódz, Łódź, Poland
| | - Marcin Słomka
- Biobank Lab, Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Łódź, Łódź, Poland
| | - Anna Rumijowska-Galewicz
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
| | - Jarosław Dziadek
- Department of Genetics and Physiology of Mycobacteria, Institute of Medical Biology of the Polish Academy of Sciences, Łódź, Poland
- *Correspondence: Jarosław Dziadek,
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18
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Antibacterial efficacy and possible mechanism of action of 2-hydroxyisocaproic acid (HICA). PLoS One 2022; 17:e0266406. [PMID: 35363830 PMCID: PMC8975099 DOI: 10.1371/journal.pone.0266406] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/18/2022] [Indexed: 12/15/2022] Open
Abstract
The exploitation of natural antimicrobial compounds that can be used in food preservation has been fast tracked by the development of antimicrobial resistance to existing antimicrobials and the increasing consumer demand for natural food preservatives. 2-hydroxyisocaproic acid (HICA) is a natural compound produced through the leucine degradation pathway and is produced in humans and by certain microorganisms such as lactic acid bacteria and Clostridium species. The present study investigated the antibacterial efficacy of HICA against some important bacteria associated with food quality and safety and provided some insights into its possible antimicrobial mechanisms against bacteria. The results revealed that HICA was effective in inhibiting the growth of tested Gram-positive and Gram-negative bacteria including a multi-drug resistant P. aeruginosa strain in this study. The underlying mechanism was investigated by measuring the cell membrane integrity, membrane permeability, membrane depolarisation, and morphological and ultrastructural changes after HICA treatment in bacterial cells. The evidence supports that HICA exerts its activity via penetration of the bacterial cell membranes, thereby causing depolarisation, rupture of membranes, subsequent leakage of cellular contents and cell death. The current study suggests that HICA has potential to be used as an antibacterial agent against food spoilage and food-borne pathogenic bacteria, targeting the bacterial cell envelope.
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19
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Sun L, Sun L, Li X, Hu X, Wang X, Nie T, Zhang Y, You X. A Novel Tigecycline Adjuvant ML-7 Reverses the Susceptibility of Tigecycline-Resistant Klebsiella pneumoniae. Front Cell Infect Microbiol 2022; 11:809542. [PMID: 35071055 PMCID: PMC8766836 DOI: 10.3389/fcimb.2021.809542] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 12/09/2021] [Indexed: 12/01/2022] Open
Abstract
The increasing incidence of tigecycline resistance undoubtedly constitutes a serious threat to global public health. The combination therapies had become the indispensable strategy against this threat. Herein, 11 clinical tigecycline-resistant Klebsiella pneumoniae which mainly has mutations in ramR, acrR, or macB were collected for tigecycline adjuvant screening. Interestingly, ML-7 hydrochloride (ML-7) dramatically potentiated tigecycline activity. We further picked up five analogs of ML-7 and evaluated their synergistic activities with tigecycline by using checkerboard assay. The results revealed that ML-7 showed certain synergy with tigecycline, while other analogs exerted attenuated synergistic effects among tigecycline-resistant isolates. Thus, ML-7 was selected for further investigation. The results from growth curves showed that ML-7 combined with tigecycline could completely inhibit the growth of bacteria, and the time-kill analysis revealed that the combination exhibited synergistic bactericidal activities for tigecycline-resistant isolates during 24 h. The ethidium bromide (EtBr) efflux assay demonstrated that ML-7 could inhibit the functions of efflux pump. Besides, ML-7 disrupted the proton motive force (PMF) via increasing ΔpH, which in turn lead to the inhibition of the functions of efflux pump, reduction of intracellular ATP levels, as well as accumulation of ROS. All of which promoted the death of bacteria. And further transcriptomic analysis revealed that genes related to the mechanism of ML-7 mainly enriched in ABC transporters. Taken together, these results revealed the potential of ML-7 as a novel tigecycline adjuvant to circumvent tigecycline-resistant Klebsiella pneumoniae.
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Affiliation(s)
- Lilan Sun
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Lang Sun
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xue Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xinxin Hu
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xiukun Wang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Tongying Nie
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Youwen Zhang
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xuefu You
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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20
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Bhaumik KN, Hetényi A, Olajos G, Martins A, Spohn R, Németh L, Jojart B, Szili P, Dunai A, Jangir PK, Daruka L, Földesi I, Kata D, Pál C, Martinek TA. Rationally designed foldameric adjuvants enhance antibiotic efficacy via promoting membrane hyperpolarization. MOLECULAR SYSTEMS DESIGN & ENGINEERING 2022; 7:21-33. [PMID: 35127141 PMCID: PMC8724909 DOI: 10.1039/d1me00118c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/06/2021] [Indexed: 05/26/2023]
Abstract
The negative membrane potential of bacterial cells influences crucial cellular processes. Inspired by the molecular scaffold of the antimicrobial peptide PGLa, we have developed antimicrobial foldamers with a computer-guided design strategy. The novel PGLa analogues induce sustained membrane hyperpolarization. When co-administered as an adjuvant, the resulting compounds - PGLb1 and PGLb2 - have substantially reduced the level of antibiotic resistance of multi-drug resistant Escherichia coli, Klebsiella pneumoniae and Shigella flexneri clinical isolates. The observed antibiotic potentiation was mediated by hyperpolarization of the bacterial membrane caused by the alteration of cellular ion transport. Specifically, PGLb1 and PGLb2 are selective ionophores that enhance the Goldman-Hodgkin-Katz potential across the bacterial membrane. These findings indicate that manipulating bacterial membrane electrophysiology could be a valuable tool to overcome antimicrobial resistance.
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Affiliation(s)
- Kaushik Nath Bhaumik
- Department of Medical Chemistry, University of Szeged Dóm tér 8 Szeged HU-6720 Hungary
| | - Anasztázia Hetényi
- Department of Medical Chemistry, University of Szeged Dóm tér 8 Szeged HU-6720 Hungary
| | - Gábor Olajos
- Department of Medical Chemistry, University of Szeged Dóm tér 8 Szeged HU-6720 Hungary
| | - Ana Martins
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
| | - Réka Spohn
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
| | - Lukács Németh
- Institute of Food Engineering, University of Szeged Szeged Hungary
| | - Balázs Jojart
- Institute of Food Engineering, University of Szeged Szeged Hungary
| | - Petra Szili
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
- Doctoral School of Multidisciplinary Medical Sciences, University of Szeged Szeged Hungary
| | - Anett Dunai
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
| | - Pramod K Jangir
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
| | - Lejla Daruka
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged Szeged Hungary
| | - Imre Földesi
- Department of Laboratory Medicine, University of Szeged Szeged Hungary
| | - Diána Kata
- Doctoral School of Biology, Faculty of Science and Informatics, University of Szeged Szeged Hungary
| | - Csaba Pál
- Synthetic and Systems Biology Unit, Biological Research Centre, Eötvös Loránd Research Network (ELKH) Szeged Hungary
| | - Tamás A Martinek
- Department of Medical Chemistry, University of Szeged Dóm tér 8 Szeged HU-6720 Hungary
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21
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Unappreciated Roles for K+ Channels in Bacterial Physiology. Trends Microbiol 2021; 29:942-950. [DOI: 10.1016/j.tim.2020.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/07/2020] [Accepted: 11/09/2020] [Indexed: 01/03/2023]
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Le D, Krasnopeeva E, Sinjab F, Pilizota T, Kim M. Active Efflux Leads to Heterogeneous Dissipation of Proton Motive Force by Protonophores in Bacteria. mBio 2021; 12:e0067621. [PMID: 34253054 PMCID: PMC8406135 DOI: 10.1128/mbio.00676-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/04/2021] [Indexed: 11/26/2022] Open
Abstract
Various toxic compounds disrupt bacterial physiology. While bacteria harbor defense mechanisms to mitigate the toxicity, these mechanisms are often coupled to the physiological state of the cells and become ineffective when the physiology is severely disrupted. Here, we characterized such feedback by exposing Escherichia coli to protonophores. Protonophores dissipate the proton motive force (PMF), a fundamental force that drives physiological functions. We found that E. coli cells responded to protonophores heterogeneously, resulting in bimodal distributions of cell growth, substrate transport, and motility. Furthermore, we showed that this heterogeneous response required active efflux systems. The analysis of underlying interactions indicated the heterogeneous response results from efflux-mediated positive feedback between PMF and protonophores' action. Our studies have broad implications for bacterial adaptation to stress, including antibiotics. IMPORTANCE An electrochemical proton gradient across the cytoplasmic membrane, alternatively known as proton motive force, energizes vital cellular processes in bacteria, including ATP synthesis, nutrient uptake, and cell division. Therefore, a wide range of organisms produce the agents that collapse the proton motive force, protonophores, to gain a competitive advantage. Studies have shown that protonophores have significant effects on microbial competition, host-pathogen interaction, and antibiotic action and resistance. Furthermore, protonophores are extensively used in various laboratory studies to perturb bacterial physiology. Here, we have characterized cell growth, substrate transport, and motility of Escherichia coli cells exposed to protonophores. Our findings demonstrate heterogeneous effects of protonophores on cell physiology and the underlying mechanism.
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Affiliation(s)
- Dai Le
- Department of Physics, Emory University, Atlanta, Georgia, USA
- Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
| | - Ekaterina Krasnopeeva
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Faris Sinjab
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Minsu Kim
- Department of Physics, Emory University, Atlanta, Georgia, USA
- Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
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23
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Crisan CV, Chandrashekar H, Everly C, Steinbach G, Hill SE, Yunker PJ, Lieberman RR, Hammer BK. A New Contact Killing Toxin Permeabilizes Cells and Belongs to a Broadly Distributed Protein Family. mSphere 2021; 6:e0031821. [PMID: 34287011 PMCID: PMC8386463 DOI: 10.1128/msphere.00318-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/21/2021] [Indexed: 01/12/2023] Open
Abstract
Vibrio cholerae is an aquatic Gram-negative bacterium that causes severe diarrheal cholera disease when ingested by humans. To eliminate competitor cells in both the external environment and inside hosts, V. cholerae uses the type VI secretion system (T6SS). The T6SS is a macromolecular contact-dependent weapon employed by many Gram-negative bacteria to deliver cytotoxic proteins into adjacent cells. In addition to canonical T6SS gene clusters encoded by all sequenced V. cholerae isolates, strain BGT49 encodes another locus, which we named auxiliary (Aux) cluster 4. The Aux 4 cluster is located on a mobile genetic element and can be used by killer cells to eliminate both V. cholerae and Escherichia coli cells in a T6SS-dependent manner. A putative toxin encoded in the cluster, which we name TpeV (type VI permeabilizing effector Vibrio), shares no homology to known proteins and does not contain motifs or domains indicative of function. Ectopic expression of TpeV in the periplasm of E. coli permeabilizes cells and disrupts the membrane potential. Using confocal microscopy, we confirm that susceptible target cells become permeabilized when competed with killer cells harboring the Aux 4 cluster. We also determine that tpiV, the gene located immediately downstream of tpeV, encodes an immunity protein that neutralizes the toxicity of TpeV. Finally, we show that TpeV homologs are broadly distributed across important human, animal, and plant pathogens and are localized in proximity to other T6SS genes. Our results suggest that TpeV is a toxin that belongs to a large family of T6SS proteins. IMPORTANCE Bacteria live in polymicrobial communities where competition for resources and space is essential for survival. Proteobacteria use the T6SS to eliminate neighboring cells and cause disease. However, the mechanisms by which many T6SS toxins kill or inhibit susceptible target cells are poorly understood. The sequence of the TpeV toxin that we describe here is unlike any previously described protein. We demonstrate that it has antimicrobial activity by permeabilizing cells, eliminating membrane potentials, and causing severe cytotoxicity. TpeV homologs are found near known T6SS genes in human, animal, and plant bacterial pathogens, indicating that the toxin is a representative member of a broadly distributed protein family. We propose that TpeV-like toxins contribute to the fitness of many bacteria. Finally, since antibiotic resistance is a critical global health threat, the discovery of new antimicrobial mechanisms could lead to the development of new treatments against resistant strains.
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Affiliation(s)
- Cristian V. Crisan
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Harshini Chandrashekar
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Catherine Everly
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Gabi Steinbach
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Shannon E. Hill
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Peter J. Yunker
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Raquel R. Lieberman
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Brian K. Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Dynamics and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
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24
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Borovsky D, Deckers K, Vanhove AC, Verstraete M, Rougé P, Shatters RG, Powell CA. Cloning and Characterization of Aedes aegypti Trypsin Modulating Oostatic Factor (TMOF) Gut Receptor. Biomolecules 2021; 11:biom11070934. [PMID: 34201823 PMCID: PMC8301768 DOI: 10.3390/biom11070934] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/18/2021] [Accepted: 06/20/2021] [Indexed: 12/17/2022] Open
Abstract
Trypsin Modulating Oostatic Factor (TMOF) receptor was solubilized from the guts of female Ae. Aegypti and cross linked to His6-TMOF and purified by Ni affinity chromatography. SDS PAGE identified two protein bands (45 and 61 kDa). The bands were cut digested and analyzed using MS/MS identifying a protein sequence (1306 amino acids) in the genome of Ae. aegypti. The mRNA of the receptor was extracted, the cDNA sequenced and cloned into pTAC-MAT-2. E. coli SbmA− was transformed with the recombinant plasmid and the receptor was expressed in the inner membrane of the bacterial cell. The binding kinetics of TMOF-FITC was then followed showing that the cloned receptor exhibits high affinity to TMOF (KD = 113.7 ± 18 nM ± SEM and Bmax = 28.7 ± 1.8 pmol ± SEM). Incubation of TMOF-FITC with E. coli cells that express the receptor show that the receptor binds TMOF and imports it into the bacterial cells, indicating that in mosquitoes the receptor imports TMOF into the gut epithelial cells. A 3D modeling of the receptor indicates that the receptor has ATP binding sites and TMOF transport into recombinant E. coli cells is inhibited with ATPase inhibitors Na Arsenate and Na Azide.
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Affiliation(s)
- Dov Borovsky
- Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz School of Medicine, Aurora, CO 80045, USA
- Correspondence:
| | - Kato Deckers
- Zoological Institute, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; (K.D.); (A.C.V.); (M.V.)
| | - Anne Catherine Vanhove
- Zoological Institute, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; (K.D.); (A.C.V.); (M.V.)
| | - Maud Verstraete
- Zoological Institute, Katholieke Universiteit Leuven, 3000 Leuven, Belgium; (K.D.); (A.C.V.); (M.V.)
| | - Pierre Rougé
- UMR 152 Pharma-Dev, Faculté des Sciences Pharmaceutiques, Institut de Recherche et Développement, Université Toulouse 3, F-31062 Toulouse, France;
| | - Robert G. Shatters
- USDA ARS, Subtropical Horticultural Laboratory, 2001 Rock Road, Ft. Pierce, FL 34945, USA;
| | - Charles A. Powell
- UF-IFAS Indian River Research and Education Center, Fort Pierce, FL 34945, USA;
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25
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Alegun O, Pandeya A, Cui J, Ojo I, Wei Y. Donnan Potential across the Outer Membrane of Gram-Negative Bacteria and Its Effect on the Permeability of Antibiotics. Antibiotics (Basel) 2021; 10:701. [PMID: 34208097 PMCID: PMC8230823 DOI: 10.3390/antibiotics10060701] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/01/2021] [Accepted: 06/07/2021] [Indexed: 11/16/2022] Open
Abstract
The cell envelope structure of Gram-negative bacteria is unique, composed of two lipid bilayer membranes and an aqueous periplasmic space sandwiched in between. The outer membrane constitutes an extra barrier to limit the exchange of molecules between the cells and the exterior environment. Donnan potential is a membrane potential across the outer membrane, resulted from the selective permeability of the membrane, which plays a pivotal role in the permeability of many antibiotics. In this review, we discussed factors that affect the intensity of the Donnan potential, including the osmotic strength and pH of the external media, the osmoregulated periplasmic glucans trapped in the periplasmic space, and the displacement of cell surface charges. The focus of our discussion is the impact of Donnan potential on the cellular permeability of selected antibiotics including fluoroquinolones, tetracyclines, β-lactams, and trimethoprim.
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Affiliation(s)
| | | | | | | | - Yinan Wei
- Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA; (O.A.); (A.P.); (J.C.); (I.O.)
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26
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Turton N, Bowers N, Khajeh S, Hargreaves IP, Heaton RA. Coenzyme Q10 and the exclusive club of diseases that show a limited response to treatment. Expert Opin Orphan Drugs 2021. [DOI: 10.1080/21678707.2021.1932459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Nadia Turton
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool UK
| | - Nathan Bowers
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool UK
| | - Sam Khajeh
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool UK
| | - Iain P Hargreaves
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool UK
| | - Robert A Heaton
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool UK
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27
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Biquet-Bisquert A, Labesse G, Pedaci F, Nord AL. The Dynamic Ion Motive Force Powering the Bacterial Flagellar Motor. Front Microbiol 2021; 12:659464. [PMID: 33927708 PMCID: PMC8076557 DOI: 10.3389/fmicb.2021.659464] [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: 01/27/2021] [Accepted: 03/02/2021] [Indexed: 11/13/2022] Open
Abstract
The bacterial flagellar motor (BFM) is a rotary molecular motor embedded in the cell membrane of numerous bacteria. It turns a flagellum which acts as a propeller, enabling bacterial motility and chemotaxis. The BFM is rotated by stator units, inner membrane protein complexes that stochastically associate to and dissociate from individual motors at a rate which depends on the mechanical and electrochemical environment. Stator units consume the ion motive force (IMF), the electrochemical gradient across the inner membrane that results from cellular respiration, converting the electrochemical energy of translocated ions into mechanical energy, imparted to the rotor. Here, we review some of the main results that form the base of our current understanding of the relationship between the IMF and the functioning of the flagellar motor. We examine a series of studies that establish a linear proportionality between IMF and motor speed, and we discuss more recent evidence that the stator units sense the IMF, altering their rates of dynamic assembly. This, in turn, raises the question of to what degree the classical dependence of motor speed on IMF is due to stator dynamics vs. the rate of ion flow through the stators. Finally, while long assumed to be static and homogeneous, there is mounting evidence that the IMF is dynamic, and that its fluctuations control important phenomena such as cell-to-cell signaling and mechanotransduction. Within the growing toolbox of single cell bacterial electrophysiology, one of the best tools to probe IMF fluctuations may, ironically, be the motor that consumes it. Perfecting our incomplete understanding of how the BFM employs the energy of ion flow will help decipher the dynamical behavior of the bacterial IMF.
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Affiliation(s)
- Anaïs Biquet-Bisquert
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université Montpellier, Montpellier, France
| | - Gilles Labesse
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université Montpellier, Montpellier, France
| | - Francesco Pedaci
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université Montpellier, Montpellier, France
| | - Ashley L Nord
- Centre de Biologie Structurale (CBS), INSERM, CNRS, Université Montpellier, Montpellier, France
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28
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Marco ML, Sanders ME, Gänzle M, Arrieta MC, Cotter PD, De Vuyst L, Hill C, Holzapfel W, Lebeer S, Merenstein D, Reid G, Wolfe BE, Hutkins R. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nat Rev Gastroenterol Hepatol 2021; 18:196-208. [PMID: 33398112 PMCID: PMC7925329 DOI: 10.1038/s41575-020-00390-5] [Citation(s) in RCA: 255] [Impact Index Per Article: 85.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/11/2020] [Indexed: 02/07/2023]
Abstract
An expert panel was convened in September 2019 by The International Scientific Association for Probiotics and Prebiotics (ISAPP) to develop a definition for fermented foods and to describe their role in the human diet. Although these foods have been consumed for thousands of years, they are receiving increased attention among biologists, nutritionists, technologists, clinicians and consumers. Despite this interest, inconsistencies related to the use of the term 'fermented' led the panel to define fermented foods and beverages as "foods made through desired microbial growth and enzymatic conversions of food components". This definition, encompassing the many varieties of fermented foods, is intended to clarify what is (and is not) a fermented food. The distinction between fermented foods and probiotics is further clarified. The panel also addressed the current state of knowledge on the safety, risks and health benefits, including an assessment of the nutritional attributes and a mechanistic rationale for how fermented foods could improve gastrointestinal and general health. The latest advancements in our understanding of the microbial ecology and systems biology of these foods were discussed. Finally, the panel reviewed how fermented foods are regulated and discussed efforts to include them as a separate category in national dietary guidelines.
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Affiliation(s)
- Maria L Marco
- Department of Food Science and Technology, University of California-Davis, Davis, CA, USA
| | - Mary Ellen Sanders
- International Scientific Association for Probiotics and Prebiotics, Centennial, CO, USA
| | - Michael Gänzle
- University of Alberta, Department of Agricultural, Food and Nutritional Science, Edmonton, Canada
| | - Marie Claire Arrieta
- Department of Physiology and Pharmacology, International Microbiome Center, University of Calgary, Calgary, Canada
| | - Paul D Cotter
- Teagasc Food Research Centre, Moorepark, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
- VistaMilk, Cork, Ireland
| | - Luc De Vuyst
- Research Group of Industrial Microbiology and Food Biotechnology, Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Colin Hill
- APC Microbiome Ireland and School of Microbiology, University College Cork, Cork, Ireland
| | - Wilhelm Holzapfel
- Advanced Green Energy and Environment Institute, Handong Global University, Pohang, Gyeongbuk, South Korea
| | - Sarah Lebeer
- Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Dan Merenstein
- Department of Family Medicine, Georgetown University, Washington, DC, USA
| | - Gregor Reid
- Lawson Health Research Institute, and Departments of Microbiology & Immunology and Surgery, University of Western Ontario, London, Ontario, Canada
| | | | - Robert Hutkins
- Department of Food Science and Technology, University of Nebraska - Lincoln, Lincoln, NE, USA.
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Watkins LC, DeGrado WF, Voth GA. Influenza A M2 Inhibitor Binding Understood through Mechanisms of Excess Proton Stabilization and Channel Dynamics. J Am Chem Soc 2020; 142:17425-17433. [PMID: 32933245 PMCID: PMC7564090 DOI: 10.1021/jacs.0c06419] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
![]()
Prevalent resistance to inhibitors
that target the influenza A
M2 proton channel has necessitated a continued drug design effort,
supported by a sustained study of the mechanism of channel function
and inhibition. Recent high-resolution X-ray crystal structures present
the first opportunity to see how the adamantyl amine class of inhibitors
bind to M2 and disrupt and interact with the channel’s water
network, providing insight into the critical properties that enable
their effective inhibition in wild-type M2. In this work, we examine
the hypothesis that these drugs act primarily as mechanism-based inhibitors
by comparing hydrated excess proton stabilization during proton transport
in M2 with the interactions revealed in the crystal structures, using
the Multiscale Reactive Molecular Dynamics (MS-RMD) methodology. MS-RMD,
unlike classical molecular dynamics, models the hydrated proton (hydronium-like
cation) as a dynamic excess charge defect and allows bonds to break
and form, capturing the intricate interactions between the hydrated
excess proton, protein atoms, and water. Through this, we show that
the ammonium group of the inhibitors is effectively positioned to
take advantage of the channel’s natural ability to stabilize
an excess protonic charge and act as a hydronium mimic. Additionally,
we show that the channel is especially stable in the drug binding
region, highlighting the importance of this property for binding the
adamantane group. Finally, we characterize an additional hinge point
near Val27, which dynamically responds to charge and inhibitor binding.
Altogether, this work further illuminates a dynamic understanding
of the mechanism of drug inhibition in M2, grounded in the fundamental
properties that enable the channel to transport and stabilize excess
protons, with critical implications for future drug design efforts.
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Affiliation(s)
- Laura C Watkins
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
| | - William F DeGrado
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94158, United States
| | - Gregory A Voth
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, United States
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30
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Kornspan D, Zahavi T, Salmon-Divon M. The Acidic Stress Response of the Intracellular Pathogen Brucella melitensis: New Insights from a Comparative, Genome-Wide Transcriptome Analysis. Genes (Basel) 2020; 11:genes11091016. [PMID: 32872264 PMCID: PMC7563570 DOI: 10.3390/genes11091016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/23/2020] [Accepted: 08/25/2020] [Indexed: 11/30/2022] Open
Abstract
The intracellular pathogenic bacteria belonging to the genus Brucella must cope with acidic stress as they penetrate the host via the gastrointestinal route, and again during the initial stages of intracellular infection. A transcription-level regulation has been proposed to explain this but the specific molecular mechanisms are yet to be determined. We recently reported a comparative transcriptomic analysis of the attenuated vaccine Brucella melitensis strain Rev.1 against the virulent strain 16M in cultures grown under either neutral or acidic conditions. Here, we re-analyze the RNA-seq data of 16M from our previous study and compare it to published transcriptomic data of this strain from both an in cellulo and an in vivo model. We identify 588 genes that are exclusively differentially expressed in 16M grown under acidic versus neutral pH conditions, including 286 upregulated genes and 302 downregulated genes that are not differentially expressed in either the in cellulo or the in vivo model. Of these, we highlight 13 key genes that are known to be associated with a bacterial response to acidic stress and, in our study, were highly upregulated under acidic conditions. These genes provide new molecular insights into the mechanisms underlying the acid-resistance of Brucella within its host.
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Affiliation(s)
- David Kornspan
- Department of Bacteriology, Kimron Veterinary Institute, Bet Dagan 50250, Israel
- Correspondence: ; Tel.: +972-3-968-1745
| | - Tamar Zahavi
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel 40700, Israel; (T.Z.); (M.S.-D.)
| | - Mali Salmon-Divon
- Genomic Bioinformatics Laboratory, Department of Molecular Biology, Ariel University, Ariel 40700, Israel; (T.Z.); (M.S.-D.)
- Adelson School of Medicine, Ariel University, Ariel 40700, Israel
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31
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Seto M, Iwasa Y. Microbial material cycling, energetic constraints and ecosystem expansion in subsurface ecosystems. Proc Biol Sci 2020; 287:20200610. [PMID: 33043868 PMCID: PMC7423649 DOI: 10.1098/rspb.2020.0610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
To harvest energy from chemical reactions, microbes engage in diverse catabolic interactions that drive material cycles in the environment. Here, we consider a simple mathematical model for cycling reactions between alternative forms of an element (A and Ae), where reaction 1 converts A to Ae and reaction 2 converts Ae to A. There are two types of microbes: type 1 microbes harness reaction 1, and type 2 microbes harness reaction 2. Each type receives its own catabolic resources from the other type and provides the other type with the by-products as the catabolic resources. Analyses of the model show that each type increases its steady-state abundance in the presence of the other type. The flux of material flow becomes faster in the presence of microbes. By coupling two catabolic reactions, types 1 and 2 can also expand their realized niches through the abundant resource premium, the effect of relative quantities of products and reactants on the available chemical energy, which is especially important for microbes under strong energetic limitations. The plausibility of mutually beneficial interactions is controlled by the available chemical energy (Gibbs energy) of the system. We conclude that mutualistic catabolic interactions can be an important factor that enables microbes in subsurface ecosystems to increase ecosystem productivity and expand the ecosystem.
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Affiliation(s)
- Mayumi Seto
- Department of Chemistry, Biology, and Environmental Sciences, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Yoh Iwasa
- Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda-shi, Hyogo 669-1337, Japan
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32
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Cho ER, Kim SS, Kang DH. Inactivation Kinetics and Membrane Potential of Pathogens in Soybean Curd Subjected to Pulsed Ohmic Heating Depending on Applied Voltage and Duty Ratio. Appl Environ Microbiol 2020; 86:e00656-20. [PMID: 32385086 PMCID: PMC7357481 DOI: 10.1128/aem.00656-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 04/28/2020] [Indexed: 11/20/2022] Open
Abstract
The aim of this research was to investigate the efficacy of the duty ratio and applied voltage in the inactivation of pathogens in soybean curd by pulsed ohmic heating (POH). The heating rate of soybean curd increased rapidly as the applied voltage increased, although the duty ratio did not affect the temperature profile. We supported this result by verifying that electrical conductivity increased with the applied voltage. Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes in soybean curd were significantly (P < 0.05) inactivated by more than 1 log unit at 80 Vrms (root mean square voltage). To elucidate the mechanism underlying these results, the membrane potential of the pathogens was examined using DiBAC4(3) [bis-(1,3-dibutylbarbituric acid)trimethine oxonol] on the basis of a previous study showing that the electric field generated by ohmic heating affected the membrane potential of cells. The values of DiBAC4(3) accumulation increased under increasing applied voltage, and they were significantly (P < 0.05) higher at 80 Vrms, while the duty ratio had no effect. In addition, morphological analysis via transmission electron microscopy showed that electroporation and expulsion of intracellular materials were predominant at 80 Vrms Moreover, electrode corrosion was overcome by the POH technique, and the textural and color properties of soybean curd were preserved. These results substantiate the idea that the applied voltage has a profound effect on the microbial inactivation of POH as a consequence of not only the thermal effect, but also the nonthermal effect, of the electric field, whereas the duty ratio does not have such an effect.IMPORTANCE High-water-activity food products, such as soybean curd, are vulnerable to microbial contamination, which causes fatal foodborne diseases and food spoilage. Inactivating microorganisms inside food is difficult because the transfer of thermal energy is slower inside than it is outside the food. POH is an adequate sterilization technique because of its rapid and uniform heating without causing electrode corrosion. To elucidate the electrical factors associated with POH performance in the inactivation of pathogens, the effects of the applied voltage and duty ratio on POH were investigated. In this study, we verified that a high applied voltage (80 Vrms) at a duty ratio of 0.1 caused thermal and nonthermal effects on pathogens that led to an approximately 4-log-unit reduction in a significantly short time. Therefore, the results of this research corroborate database predictions of the inactivation efficiency of POH based on pathogen control strategy modeling.
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Affiliation(s)
- Eun-Rae Cho
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sang-Soon Kim
- Department of Food Engineering, Dankook University, Cheonan, Chungnam, Republic of Korea
| | - Dong-Hyun Kang
- Department of Agricultural Biotechnology, Center for Food and Bioconvergence, and Research Institute for Agricultural and Life Sciences, Seoul National University, Seoul, Republic of Korea
- Institutes of Green Bio Science and Technology, Seoul National University, Seoul, Republic of Korea
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33
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Liu Y, Jia Y, Yang K, Li R, Xiao X, Zhu K, Wang Z. Metformin Restores Tetracyclines Susceptibility against Multidrug Resistant Bacteria. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:1902227. [PMID: 32596101 PMCID: PMC7312304 DOI: 10.1002/advs.201902227] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 03/29/2020] [Indexed: 05/22/2023]
Abstract
Highly persistent incidence of multidrug resistant (MDR) bacterial pathogens constitutes a global burden for public health. An alternative strategy to alleviate such a crisis is to identify promising compounds to restore antibiotics activity against MDR bacteria. It is reported that the antidiabetic drug metformin exhibits the potentiation effect on tetracycline antibiotics, particularly doxycycline and minocycline, against MDR S. aureus, E. faecalis, E. coli, and S. enteritidis. Mechanistic studies demonstrate that metformin promotes intracellular accumulation of doxycycline in tetracycline-resistant E. coli. In addition, metformin boosts the immune response and alleviates the inflammatory responses in vitro. Last, metformin fully restores the activity of doxycycline in three animal infection models. Collectively, these results reveal the potential of metformin as a novel tetracyclines adjuvant to circumvent MDR bacterial pathogens and to improve the treatment outcome of recalcitrant infections.
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Affiliation(s)
- Yuan Liu
- Institute of Comparative MedicineCollege of Veterinary MedicineYangzhou UniversityYangzhouJiangsu225009China
- Jiangsu Co‐innovation Center for Prevention and Control of Important Animal Infectious Diseases and ZoonosesYangzhouJiangsu225009China
| | - Yuqian Jia
- Institute of Comparative MedicineCollege of Veterinary MedicineYangzhou UniversityYangzhouJiangsu225009China
| | - Kangni Yang
- Institute of Comparative MedicineCollege of Veterinary MedicineYangzhou UniversityYangzhouJiangsu225009China
| | - Ruichao Li
- Institute of Comparative MedicineCollege of Veterinary MedicineYangzhou UniversityYangzhouJiangsu225009China
- Jiangsu Co‐innovation Center for Prevention and Control of Important Animal Infectious Diseases and ZoonosesYangzhouJiangsu225009China
| | - Xia Xiao
- Institute of Comparative MedicineCollege of Veterinary MedicineYangzhou UniversityYangzhouJiangsu225009China
- Jiangsu Co‐innovation Center for Prevention and Control of Important Animal Infectious Diseases and ZoonosesYangzhouJiangsu225009China
| | - Kui Zhu
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Veterinary MedicineChina Agricultural UniversityBeijing100193China
| | - Zhiqiang Wang
- Institute of Comparative MedicineCollege of Veterinary MedicineYangzhou UniversityYangzhouJiangsu225009China
- Jiangsu Co‐innovation Center for Prevention and Control of Important Animal Infectious Diseases and ZoonosesYangzhouJiangsu225009China
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34
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Benarroch JM, Asally M. The Microbiologist’s Guide to Membrane Potential Dynamics. Trends Microbiol 2020; 28:304-314. [DOI: 10.1016/j.tim.2019.12.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/25/2019] [Accepted: 12/09/2019] [Indexed: 10/25/2022]
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35
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Affiliation(s)
- Rimzhim Gupta
- Department of Chemical EngineeringIndian Institute of Science Bangalore, Karnataka 560012 India
| | - Jayant Modak
- Department of Chemical EngineeringIndian Institute of Science Bangalore, Karnataka 560012 India
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36
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Ito T, Gallegos R, Matano LM, Butler NL, Hantman N, Kaili M, Coyne MJ, Comstock LE, Malamy MH, Barquera B. Genetic and Biochemical Analysis of Anaerobic Respiration in Bacteroides fragilis and Its Importance In Vivo. mBio 2020; 11:e03238-19. [PMID: 32019804 PMCID: PMC7002350 DOI: 10.1128/mbio.03238-19] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 12/13/2019] [Indexed: 12/14/2022] Open
Abstract
In bacteria, the respiratory pathways that drive molecular transport and ATP synthesis include a variety of enzyme complexes that utilize different electron donors and acceptors. This property allows them to vary the efficiency of energy conservation and to generate different types of electrochemical gradients (H+ or Na+). We know little about the respiratory pathways in Bacteroides species, which are abundant in the human gut, and whether they have a simple or a branched pathway. Here, we combined genetics, enzyme activity measurements, and mammalian gut colonization assays to better understand the first committed step in respiration, the transfer of electrons from NADH to quinone. We found that a model gut Bacteroides species, Bacteroides fragilis, has all three types of putative NADH dehydrogenases that typically transfer electrons from the highly reducing molecule NADH to quinone. Analyses of NADH oxidation and quinone reduction in wild-type and deletion mutants showed that two of these enzymes, Na+-pumping NADH:quinone oxidoreductase (NQR) and NADH dehydrogenase II (NDH2), have NADH dehydrogenase activity, whereas H+-pumping NADH:ubiquinone oxidoreductase (NUO) does not. Under anaerobic conditions, NQR contributes more than 65% of the NADH:quinone oxidoreductase activity. When grown in rich medium, none of the single deletion mutants had a significant growth defect; however, the double Δnqr Δndh2 mutant, which lacked almost all NADH:quinone oxidoreductase activity, had a significantly increased doubling time. Despite unaltered in vitro growth, the single nqr deletion mutant was unable to competitively colonize the gnotobiotic mouse gut, confirming the importance of NQR to respiration in B. fragilis and the overall importance of respiration to this abundant gut symbiont.IMPORTANCEBacteroides species are abundant in the human intestine and provide numerous beneficial properties to their hosts. The ability of Bacteroides species to convert host and dietary glycans and polysaccharides to energy is paramount to their success in the human gut. We know a great deal about the molecules that these bacteria extract from the human gut but much less about how they convert those molecules into energy. Here, we show that B. fragilis has a complex respiratory pathway with two different enzymes that transfer electrons from NADH to quinone and a third enzyme complex that may use an electron donor other than NADH. Although fermentation has generally been believed to be the main mechanism of energy generation in Bacteroides, we found that a mutant lacking one of the NADH:quinone oxidoreductases was unable to compete with the wild type in the mammalian gut, revealing the importance of respiration to these abundant gut symbionts.
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Affiliation(s)
- Takeshi Ito
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Rene Gallegos
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Leigh M Matano
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Nicole L Butler
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Noam Hantman
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Matthew Kaili
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Michael J Coyne
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Laurie E Comstock
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael H Malamy
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Blanca Barquera
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York, USA
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37
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Mariano G, Trunk K, Williams DJ, Monlezun L, Strahl H, Pitt SJ, Coulthurst SJ. A family of Type VI secretion system effector proteins that form ion-selective pores. Nat Commun 2019; 10:5484. [PMID: 31792213 PMCID: PMC6889166 DOI: 10.1038/s41467-019-13439-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 11/05/2019] [Indexed: 12/25/2022] Open
Abstract
Type VI secretion systems (T6SSs) are nanomachines widely used by bacteria to deliver toxic effector proteins directly into neighbouring cells. However, the modes of action of many effectors remain unknown. Here we report that Ssp6, an anti-bacterial effector delivered by a T6SS of the opportunistic pathogen Serratia marcescens, is a toxin that forms ion-selective pores. Ssp6 inhibits bacterial growth by causing depolarisation of the inner membrane in intoxicated cells, together with increased outer membrane permeability. Reconstruction of Ssp6 activity in vitro demonstrates that it forms cation-selective pores. A survey of bacterial genomes reveals that genes encoding Ssp6-like effectors are widespread in Enterobacteriaceae and often linked with T6SS genes. We conclude that Ssp6 and similar proteins represent a new family of T6SS-delivered anti-bacterial effectors.
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Affiliation(s)
- Giuseppina Mariano
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Katharina Trunk
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - David J Williams
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Laura Monlezun
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, UK
| | - Henrik Strahl
- Centre for Bacterial Cell Biology, Newcastle University, Richardson Road, Newcastle-upon-Tyne, NE2 4AX, UK
| | - Samantha J Pitt
- School of Medicine, University of St Andrews, North Haugh, St Andrews, KY16 9TF, UK
| | - Sarah J Coulthurst
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dow St, Dundee, DD1 5EH, UK.
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38
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Glucose-Induced Cyclic Lipopeptides Resistance in Bacteria via ATP Maintenance through Enhanced Glycolysis. iScience 2019; 21:135-144. [PMID: 31655254 PMCID: PMC6820274 DOI: 10.1016/j.isci.2019.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/20/2019] [Accepted: 10/01/2019] [Indexed: 01/28/2023] Open
Abstract
Cyclic lipopeptide (CLP) antibiotics have a mechanism that causes membrane malfunction. Thus mechanisms of bacterial resistance to CLPs are thought to modify cell surfaces. However, we found that bacterial resistance to CLPs was strongly related to energy metabolism. Using polymyxin B (PB) as a model of CLPs, we showed that PB causes malfunction of respiration and serious depletion of ATP, contributing to PB-induced cell death and carbon starvation. Glucose addition could maintain the intracellular ATP level and reverse the carbon starvation response resulting from PB treatment. Another study revealed that glycolysis was stimulated by the presence of PB and glucose. The mechanism underlying glucose-enabled CLPs' resistance suggests that glucose could maintain the ATP level in PB-treated bacteria by enhancing glycolysis. Similar results were observed in Staphylococcus aureus, where daptomycin resistance was enhanced by glucose. These findings provide insight into the mode of action of CLPs and resistance to these antibiotics. Glucose induces the drug resistance to CLPs CLPs significantly inhibit energy metabolism and result in ATP depletion Glucose maintains the intracellular ATP level in CLP-treated bacteria
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39
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General Mechanisms Leading to Persister Formation and Awakening. Trends Genet 2019; 35:401-411. [DOI: 10.1016/j.tig.2019.03.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/20/2019] [Accepted: 03/27/2019] [Indexed: 11/18/2022]
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40
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Quintero-Yanes A, Monson RE, Salmond GPC. Environmental potassium regulates bacterial flotation, antibiotic production and turgor pressure in Serratia through the TrkH transporter. Environ Microbiol 2019; 21:2499-2510. [PMID: 31012245 PMCID: PMC6617781 DOI: 10.1111/1462-2920.14637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/16/2019] [Accepted: 04/21/2019] [Indexed: 11/28/2022]
Abstract
Serratia sp. strain ATCC 39006 (S39006) can float in aqueous environments due to natural production of gas vesicles (GVs). Expression of genes for GV morphogenesis is stimulated in low oxygen conditions, thereby enabling migration to the air–liquid interface. Quorum sensing (via SmaI and SmaR) and transcriptional and post‐transcriptional regulators, including RbsR and RsmA, respectively, connect the control of cell buoyancy, motility and secondary metabolism. Here, we define a new pleiotropic regulator found in screens of GV mutants. A mutation in the gene trkH, encoding a potassium transporter, caused upregulation of GV formation, flotation, and the prodigiosin antibiotic, and downregulation of flagellar motility. Pressure nephelometry revealed that the mutation in trkH affected cell turgor pressure. Our results show that osmotic change is an important physiological parameter modulating cell buoyancy and antimicrobial production in S39006, in response to environmental potassium levels.
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Affiliation(s)
- Alex Quintero-Yanes
- Department of Biochemistry, University of Cambridge, Hopkins Building, Downing Site. Cambridge, CB2 1QW, UK
| | - Rita E Monson
- Department of Biochemistry, University of Cambridge, Hopkins Building, Downing Site. Cambridge, CB2 1QW, UK
| | - George P C Salmond
- Department of Biochemistry, University of Cambridge, Hopkins Building, Downing Site. Cambridge, CB2 1QW, UK
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41
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Zarco-Zavala M, Mendoza-Hoffmann F, García-Trejo JJ. Unidirectional regulation of the F 1F O-ATP synthase nanomotor by the ζ pawl-ratchet inhibitor protein of Paracoccus denitrificans and related α-proteobacteria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2018; 1859:762-774. [PMID: 29886048 DOI: 10.1016/j.bbabio.2018.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/28/2018] [Accepted: 06/05/2018] [Indexed: 12/20/2022]
Abstract
The ATP synthase is a reversible nanomotor that gyrates its central rotor clockwise (CW) to synthesize ATP and in counter clockwise (CCW) direction to hydrolyse it. In bacteria and mitochondria, two natural inhibitor proteins, namely the ε and IF1 subunits, prevent the wasteful CCW F1FO-ATPase activity by blocking γ rotation at the αDP/βDP/γ interface of the F1 portion. In Paracoccus denitrificans and related α-proteobacteria, we discovered a different natural F1-ATPase inhibitor named ζ. Here we revise the functional and structural data showing that this novel ζ subunit, although being different to ε and IF1, it also binds to the αDP/βDP/γ interface of the F1 of P. denitrificans. ζ shifts its N-terminal inhibitory domain from an intrinsically disordered protein region (IDPr) to an α-helix when inserted in the αDP/βDP/γ interface. We showed for the first time the key role of a natural ATP synthase inhibitor by the distinctive phenotype of a Δζ knockout mutant in P. denitrificans. ζ blocks exclusively the CCW F1FO-ATPase rotation without affecting the CW-F1FO-ATP synthase turnover, confirming that ζ is important for respiratory bacterial growth by working as a unidirectional pawl-ratchet PdF1FO-ATPase inhibitor, thus preventing the wasteful consumption of cellular ATP. In summary, ζ is a useful model that mimics mitochondrial IF1 but in α-proteobacteria. The structural, functional, and endosymbiotic evolutionary implications of this ζ inhibitor are discussed to shed light on the natural control mechanisms of the three natural inhibitor proteins (ε, ζ, and IF1) of this unique ATP synthase nanomotor, essential for life.
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Affiliation(s)
- Mariel Zarco-Zavala
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX), CP 04510, Mexico; Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Francisco Mendoza-Hoffmann
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX), CP 04510, Mexico
| | - José J García-Trejo
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX), CP 04510, Mexico.
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Cholo MC, Mothiba MT, Fourie B, Anderson R. Mechanisms of action and therapeutic efficacies of the lipophilic antimycobacterial agents clofazimine and bedaquiline. J Antimicrob Chemother 2016; 72:338-353. [PMID: 27798208 DOI: 10.1093/jac/dkw426] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Drug-resistant (DR)-TB is the major challenge confronting the global TB control programme, necessitating treatment with second-line anti-TB drugs, often with limited therapeutic efficacy. This scenario has resulted in the inclusion of Group 5 antibiotics in various therapeutic regimens, two of which promise to impact significantly on the outcome of the therapy of DR-TB. These are the 're-purposed' riminophenazine, clofazimine, and the recently approved diarylquinoline, bedaquiline. Although they differ structurally, both of these lipophilic agents possess cationic amphiphilic properties that enable them to target and inactivate essential ion transporters in the outer membrane of Mycobacterium tuberculosis. In the case of bedaquiline, the primary target is the key respiratory chain enzyme F1/F0-ATPase, whereas clofazimine is less selective, apparently inhibiting several targets, which may underpin the extremely low level of resistance to this agent. This review is focused on similarities and differences between clofazimine and bedaquiline, specifically in respect of molecular mechanisms of antimycobacterial action, targeting of quiescent and metabolically active organisms, therapeutic efficacy in the clinical setting of DR-TB, resistance mechanisms, pharmacodynamics, pharmacokinetics and adverse events.
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Affiliation(s)
- Moloko C Cholo
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
| | - Maborwa T Mothiba
- Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
| | - Bernard Fourie
- Department of Medical Microbiology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
| | - Ronald Anderson
- Institute for Cellular and Molecular Medicine, Department of Immunology, Faculty of Health Sciences, University of Pretoria, Pretoria 0001, South Africa
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Carlson ML, Bao H, Duong F. Formation of a Chloride-conducting State in the Maltose ATP-binding Cassette (ABC) Transporter. J Biol Chem 2016; 291:12119-25. [PMID: 27059961 DOI: 10.1074/jbc.m115.711622] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Indexed: 11/06/2022] Open
Abstract
ATP-binding cassette transporters use an alternating access mechanism to move substrates across cellular membranes. This mode of transport ensures the selective passage of molecules while preserving membrane impermeability. The crystal structures of MalFGK2, inward- and outward-facing, show that the transporter is sealed against ions and small molecules. It has yet to be determined whether membrane impermeability is maintained when MalFGK2 cycles between these two conformations. Through the use of a mutant that resides in intermediate conformations close to the transition state, we demonstrate that not only is chloride conductance occurring, but also to a degree large enough to compromise cell viability. Introduction of mutations in the periplasmic gate lead to the formation of a channel that is quasi-permanently open. MalFGK2 must therefore stay away from these ion-conducting conformations to preserve the membrane barrier; otherwise, a few mutations that increase access to the ion-conducting states are enough to convert an ATP-binding cassette transporter into a channel.
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Affiliation(s)
- Michael L Carlson
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Huan Bao
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Franck Duong
- From the Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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44
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Affiliation(s)
- Sundus Erbas-Cakmak
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - David A. Leigh
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Charlie T. McTernan
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Alina
L. Nussbaumer
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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45
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Biology and Assembly of the Bacterial Envelope. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 883:41-76. [PMID: 26621461 DOI: 10.1007/978-3-319-23603-2_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
All free-living bacterial cells are delimited and protected by an envelope of high complexity. This physiological barrier is essential for bacterial survival and assures multiple functions. The molecular assembly of the different envelope components into a functional structure represents a tremendous biological challenge and is of high interest for fundamental sciences. The study of bacterial envelope assembly has also been fostered by the need for novel classes of antibacterial agents to fight the problematic of bacterial resistance to antibiotics. This chapter focuses on the two most intensively studied classes of bacterial envelopes that belong to the phyla Firmicutes and Proteobacteria. The envelope of Firmicutes typically has one membrane and is defined as being monoderm whereas the envelope of Proteobacteria contains two distinct membranes and is referred to as being diderm. In this chapter, we will first discuss the multiple roles of the bacterial envelope and clarify the nomenclature used to describe the different types of envelopes. We will then define the architecture and composition of the envelopes of Firmicutes and Proteobacteria while outlining their similarities and differences. We will further cover the extensive progress made in the field of bacterial envelope assembly over the last decades, using Bacillus subtilis and Escherichia coli as model systems for the study of the monoderm and diderm bacterial envelopes, respectively. We will detail our current understanding of how molecular machines assure the secretion, insertion and folding of the envelope proteins as well as the assembly of the glycosidic components of the envelope. Finally, we will highlight the topics that are still under investigation, and that will surely lead to important discoveries in the near future.
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Ehrensberger MT, Tobias ME, Nodzo SR, Hansen LA, Luke-Marshall NR, Cole RF, Wild LM, Campagnari AA. Cathodic voltage-controlled electrical stimulation of titanium implants as treatment for methicillin-resistant Staphylococcus aureus periprosthetic infections. Biomaterials 2014; 41:97-105. [PMID: 25522969 DOI: 10.1016/j.biomaterials.2014.11.013] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/31/2014] [Accepted: 11/07/2014] [Indexed: 11/17/2022]
Abstract
Effective treatment options are often limited for implant-associated orthopedic infections. In this study we evaluated the antimicrobial effects of applying cathodic voltage-controlled electrical stimulation (CVCES) of -1.8 V (vs. Ag/AgCl) to commercially pure titanium (cpTi) substrates with preformed biofilm-like structures of methicillin-resistant Staphylococcus aureus (MRSA). The in vitro studies showed that as compared to the open circuit potential (OCP) conditions, CVCES of -1.8 V for 1 h significantly reduced the colony-forming units (CFU) of MRSA enumerated from the cpTi by 97% (1.89 × 106 vs 6.45 × 104 CFU/ml) and from the surrounding solution by 92% (6.63 × 105 vs. 5.15 × 104 CFU/ml). The in vivo studies, utilizing a rodent periprosthetic infection model, showed that as compared to the OCP conditions, CVCES at -1.8 V for 1 h significantly reduced MRSA CFUs in the bone tissue by 87% (1.15 × 105 vs. 1.48 × 104 CFU/ml) and reduced CFU on the cpTi implant by 98% (5.48 × 104 vs 1.16 × 103 CFU/ml). The stimulation was not associated with histological changes in the host tissue surrounding the implant. As compared to the OCP conditions, the -1.8 V stimulation significantly increased the interfacial capacitance (18.93 vs. 98.25 μF/cm(2)) and decreased polarization resistance (868,250 vs. 108 Ω-cm(2)) of the cpTi. The antimicrobial effects are thought to be associated with these voltage-dependent electrochemical surface properties of the cpTi.
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Affiliation(s)
- Mark T Ehrensberger
- Department of Biomedical Engineering, State University of New York at Buffalo, 162 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA; Department of Orthopedics, State University of New York at Buffalo, 162 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA.
| | - Menachem E Tobias
- Department of Orthopedics, State University of New York at Buffalo, 162 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA
| | - Scott R Nodzo
- Department of Orthopedics, State University of New York at Buffalo, 162 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA
| | - Lisa A Hansen
- Department of Microbiology and Immunology, State University of New York at Buffalo, 140 Biomedical Research Building, 3435 Main Street, Buffalo, NY 14214, USA
| | - Nicole R Luke-Marshall
- Department of Microbiology and Immunology, State University of New York at Buffalo, 140 Biomedical Research Building, 3435 Main Street, Buffalo, NY 14214, USA
| | - Ross F Cole
- Department of Orthopedics, State University of New York at Buffalo, 162 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA
| | - Linda M Wild
- Department of Pathology and Anatomical Sciences, State University of New York at Buffalo, 204 Farber Hall, 3435 Main Street, Buffalo, NY 14214, USA
| | - Anthony A Campagnari
- Department of Microbiology and Immunology, State University of New York at Buffalo, 140 Biomedical Research Building, 3435 Main Street, Buffalo, NY 14214, USA
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Ruhe ZC, Nguyen JY, Beck CM, Low DA, Hayes CS. The proton-motive force is required for translocation of CDI toxins across the inner membrane of target bacteria. Mol Microbiol 2014; 94:466-81. [PMID: 25174572 DOI: 10.1111/mmi.12779] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2014] [Indexed: 01/09/2023]
Abstract
Contact-dependent growth inhibition (CDI) is a mode of bacterial competition orchestrated by the CdiB/CdiA family of two-partner secretion proteins. The CdiA effector extends from the surface of CDI(+) inhibitor cells, binds to receptors on neighbouring bacteria and delivers a toxin domain derived from its C-terminal region (CdiA-CT). Here, we show that CdiA-CT toxin translocation requires the proton-motive force (pmf) within target bacteria. The pmf is also critical for the translocation of colicin toxins, which exploit the energized Ton and Tol systems to cross the outer membrane. However, CdiA-CT translocation is clearly distinct from known colicin-import pathways because ΔtolA ΔtonB target cells are fully sensitive to CDI. Moreover, we provide evidence that CdiA-CT toxins can be transferred into the periplasm of de-energized target bacteria, indicating that transport across the outer membrane is independent of the pmf. Remarkably, CDI toxins transferred under de-energized conditions remain competent to enter the target-cell cytoplasm once the pmf is restored. Collectively, these results indicate that outer- and inner-membrane translocation steps can be uncoupled, and that the pmf is required for CDI toxin transport from the periplasm to the target-cell cytoplasm.
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Affiliation(s)
- Zachary C Ruhe
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA, 93106-9625, USA
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Temperton B, Gilbert JA, Quinn JP, McGrath JW. Novel analysis of oceanic surface water metagenomes suggests importance of polyphosphate metabolism in oligotrophic environments. PLoS One 2011; 6:e16499. [PMID: 21305044 PMCID: PMC3030594 DOI: 10.1371/journal.pone.0016499] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Accepted: 12/20/2010] [Indexed: 11/21/2022] Open
Abstract
Polyphosphate is a ubiquitous linear homopolymer of phosphate residues linked by high-energy bonds similar to those found in ATP. It has been associated with many processes including pathogenicity, DNA uptake and multiple stress responses across all domains. Bacteria have also been shown to use polyphosphate as a way to store phosphate when transferred from phosphate-limited to phosphate-rich media--a process exploited in wastewater treatment and other environmental contaminant remediation. Despite this, there has, to date, been little research into the role of polyphosphate in the survival of marine bacterioplankton in oligotrophic environments. The three main proteins involved in polyphosphate metabolism, Ppk1, Ppk2 and Ppx are multi-domain and have differential inter-domain and inter-gene conservation, making unbiased analysis of relative abundance in metagenomic datasets difficult. This paper describes the development of a novel Isofunctional Homolog Annotation Tool (IHAT) to detect homologs of genes with a broad range of conservation without bias of traditional expect-value cutoffs. IHAT analysis of the Global Ocean Sampling (GOS) dataset revealed that genes associated with polyphosphate metabolism are more abundant in environments where available phosphate is limited, suggesting an important role for polyphosphate metabolism in marine oligotrophs.
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Affiliation(s)
- Ben Temperton
- School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom.
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49
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Northen H, Paterson GK, Constantino-Casas F, Bryant CE, Clare S, Mastroeni P, Peters SE, Maskell DJ. Salmonella enterica serovar Typhimurium mutants completely lacking the F(0)F(1) ATPase are novel live attenuated vaccine strains. Vaccine 2009; 28:940-9. [PMID: 19925904 PMCID: PMC3898827 DOI: 10.1016/j.vaccine.2009.10.146] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 10/27/2009] [Accepted: 10/29/2009] [Indexed: 12/31/2022]
Abstract
The F0F1 ATPase plays a central role in both the generation of ATP and the utilisation of ATP for cellular processes such as rotation of bacterial flagella. We have deleted the entire operon encoding the F0F1 ATPase, as well as genes encoding individual F0 or F1 subunits, in Salmonella enteric serovar Typhimurium. These mutants were attenuated for virulence, as assessed by bacterial counts in the livers and spleens of intravenously infected mice. The attenuated in vivo growth of the entire atp operon mutant was complemented by the insertion of the atp operon into the malXY pseudogene region. Following clearance of the attenuated mutants from the organs, mice were protected against challenge with the virulent wild type parent strain. We have shown that the F0F1 ATPase is important for bacterial growth in vivo and that atp mutants are effective live attenuated vaccines against Salmonella infection.
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Affiliation(s)
- H Northen
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
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50
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Facucho-Oliveira JM, St John JC. The relationship between pluripotency and mitochondrial DNA proliferation during early embryo development and embryonic stem cell differentiation. Stem Cell Rev Rep 2009; 5:140-58. [PMID: 19521804 DOI: 10.1007/s12015-009-9058-0] [Citation(s) in RCA: 172] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 02/04/2009] [Indexed: 01/01/2023]
Abstract
Pluripotent blastomeres of mammalian pre-implantation embryos and embryonic stem cells (ESCs) are characterized by limited oxidative capacity and great reliance on anaerobic respiration. Early pre-implantation embryos and undifferentiated ESCs possess small and immature mitochondria located around the nucleus, have low oxygen consumption and express high levels of glycolytic enzymes. However, as embryonic cells and ESCs lose pluripotency and commit to a specific cell fate, the expression of mtDNA transcription and replication factors is upregulated and the number of mitochondria and mtDNA copies/cell increases. Moreover, upon cellular differentiation, mitochondria acquire an elongated morphology with swollen cristae and dense matrices, migrate into wider cytoplasmic areas and increase the levels of oxygen consumption and ATP production as a result of the activation of the more efficient, aerobic metabolism. Since pluripotency seems to be associated with anaerobic metabolism and a poorly developed mitochondrial network and differentiation leads to activation of mitochondrial biogenesis according to the metabolic requirements of the specific cell type, it is hypothesized that reprogramming of somatic cells towards a pluripotent state, by somatic cell nuclear transfer (SCNT), transcription-induced pluripotency or creation of pluripotent cell hybrids, requires acquisition of mitochondrial properties characteristic of pluripotent blastomeres and ESCs.
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Affiliation(s)
- J M Facucho-Oliveira
- The Mitochondrial and Reproductive Genetics Group, Clinical Sciences Research Institute, Warwick Medical School, University of Warwick, Warwick CV2 2DX, UK
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