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Feng J, Zheng Y, Ma W, Weng D, Peng D, Xu Y, Wang Z, Wang X. A synthetic antibiotic class with a deeply-optimized design for overcoming bacterial resistance. Nat Commun 2024; 15:6040. [PMID: 39019927 PMCID: PMC11255307 DOI: 10.1038/s41467-024-50453-3] [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: 12/01/2023] [Accepted: 07/10/2024] [Indexed: 07/19/2024] Open
Abstract
The lack of new drugs that are effective against antibiotic-resistant bacteria has caused increasing concern in global public health. Based on this study, we report development of a modified antimicrobial drug through structure-based drug design (SBDD) and modular synthesis. The optimal modified compound, F8, was identified, which demonstrated in vitro and in vivo broad-spectrum antibacterial activity against drug-resistant bacteria and effectively mitigated the development of resistance. F8 exhibits significant bactericidal activity against bacteria resistant to antibiotics such as methicillin, polymyxin B, florfenicol (FLO), doxycycline, ampicillin and sulfamethoxazole. In a mouse model of drug-resistant bacteremia, F8 was found to increase survival and significantly reduce bacterial load in infected mice. Multi-omics analysis (transcriptomics, proteomics, and metabolomics) have indicated that ornithine carbamoyl transferase (arcB) is a antimicrobial target of F8. Further molecular docking, Isothermal Titration Calorimetry (ITC), and Differential Scanning Fluorimetry (DSF) studies verified arcB as a effective target for F8. Finally, mechanistic studies suggest that F8 competitively binds to arcB, disrupting the bacterial cell membrane and inducing a certain degree of oxidative damage. Here, we report F8 as a promising candidate drug for the development of antibiotic formulations to combat antibiotic-resistant bacteria-associated infections.
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Affiliation(s)
- Jin Feng
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Youle Zheng
- MAO Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Wanqing Ma
- MAO Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Defeng Weng
- MAO Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Dapeng Peng
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, China
- MAO Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China
| | - Yindi Xu
- Institute of Animal Husbandry and Veterinary Research, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, China
| | - Zhifang Wang
- Institute of Animal Husbandry and Veterinary Research, Henan Academy of Agricultural Sciences, Zhengzhou, Henan, China
| | - Xu Wang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, China.
- MAO Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, China.
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Bravo A, Moreno-Blanco A, Espinosa M. One Earth: The Equilibrium between the Human and the Bacterial Worlds. Int J Mol Sci 2023; 24:15047. [PMID: 37894729 PMCID: PMC10606248 DOI: 10.3390/ijms242015047] [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: 08/17/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/29/2023] Open
Abstract
Misuse and abuse of antibiotics on humans, cattle, and crops have led to the selection of multi-resistant pathogenic bacteria, the most feared 'superbugs'. Infections caused by superbugs are progressively difficult to treat, with a subsequent increase in lethality: the toll on human lives is predicted to reach 10 million by 2050. Here we review three concepts linked to the growing resistance to antibiotics, namely (i) the Resistome, which refers to the collection of bacterial genes that confer resistance to antibiotics, (ii) the Mobilome, which includes all the mobile genetic elements that participate in the spreading of antibiotic resistance among bacteria by horizontal gene transfer processes, and (iii) the Nichome, which refers to the set of genes that are expressed when bacteria try to colonize new niches. We also discuss the strategies that can be used to tackle bacterial infections and propose an entente cordiale with the bacterial world so that instead of war and destruction of the 'fierce enemy' we can achieve a peaceful coexistence (the One Earth concept) between the human and the bacterial worlds. This, in turn, will contribute to microbial biodiversity, which is crucial in a globally changing climate due to anthropogenic activities.
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Affiliation(s)
- Alicia Bravo
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, E-28040 Madrid, Spain
| | | | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Ramiro de Maeztu 9, E-28040 Madrid, Spain
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3
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Chan WT, Garcillán-Barcia MP, Yeo CC, Espinosa M. Type II bacterial toxin-antitoxins: hypotheses, facts, and the newfound plethora of the PezAT system. FEMS Microbiol Rev 2023; 47:fuad052. [PMID: 37715317 PMCID: PMC10532202 DOI: 10.1093/femsre/fuad052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 09/17/2023] Open
Abstract
Toxin-antitoxin (TA) systems are entities found in the prokaryotic genomes, with eight reported types. Type II, the best characterized, is comprised of two genes organized as an operon. Whereas toxins impair growth, the cognate antitoxin neutralizes its activity. TAs appeared to be involved in plasmid maintenance, persistence, virulence, and defence against bacteriophages. Most Type II toxins target the bacterial translational machinery. They seem to be antecessors of Higher Eukaryotes and Prokaryotes Nucleotide-binding (HEPN) RNases, minimal nucleotidyltransferase domains, or CRISPR-Cas systems. A total of four TAs encoded by Streptococcus pneumoniae, RelBE, YefMYoeB, Phd-Doc, and HicAB, belong to HEPN-RNases. The fifth is represented by PezAT/Epsilon-Zeta. PezT/Zeta toxins phosphorylate the peptidoglycan precursors, thereby blocking cell wall synthesis. We explore the body of knowledge (facts) and hypotheses procured for Type II TAs and analyse the data accumulated on the PezAT family. Bioinformatics analyses showed that homologues of PezT/Zeta toxin are abundantly distributed among 14 bacterial phyla mostly in Proteobacteria (48%), Firmicutes (27%), and Actinobacteria (18%), showing the widespread distribution of this TA. The pezAT locus was found to be mainly chromosomally encoded whereas its homologue, the tripartite omega-epsilon-zeta locus, was found mostly on plasmids. We found several orphan pezT/zeta toxins, unaccompanied by a cognate antitoxin.
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Affiliation(s)
- Wai Ting Chan
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Maria Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-Consejo Superior de Investigaciones Científicas, C/Albert Einstein 22, PCTCAN, 39011 Santander, Spain
| | - Chew Chieng Yeo
- Centre for Research in Infectious Diseases and Biotechnology (CeRIDB), Faculty of Medicine
, Universiti Sultan Zainal Abidin, Jalan Sultan Mahumd, 20400 Kuala Terengganu, Malaysia
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
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4
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Santos AM, Carvalho Santana Júnior C, Nascimento Júnior JAC, Andrade TDA, Shanmugam S, Thangaraj P, Frank LA, Serafini MR. Antibacterial drugs and cyclodextrin inclusion complexes: a patent review. Expert Opin Drug Deliv 2023; 20:349-366. [PMID: 36722254 DOI: 10.1080/17425247.2023.2175815] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Bacterial antibiotic resistance occurs when bacteria mutate and escape the effect of antibiotics, which makes the antibiotics no longer effective in treating infections. New solutions for bacterial infections are a persistent need including the identification of drugs with better pharmacological profiles, more potent, and safer. Cyclodextrins inclusion complexes have been able to improve the physicochemical and pharmacological properties of the formulation molecules, resulting in new alternatives with better efficacy. AREAS COVERED The patents analyzed in the review used treatments based on antibiotics already on the market, natural products, and synthesized molecules composed of the formulation with cyclodextrins. The combination between cyclodextrin and nanostructures also were presented in the patents review process. Moreover, inclusion complexes have been an alternative in developing treatment mainly in China by the pharmaceutical industries in several countries such as Germany, Hungary, the United States of America, Japan and China. EXPERT OPINION This review is broad and complete since it considers the first patent involving cyclodextrins and antibacterial drugs. Therefore, the various inclusion complexes and antibacterial drugs alternatives presented in this review offer therapeutic options to fight bacterial infections. If shown to be effective, these drugs may be extremely important in the current clinical practice.
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Affiliation(s)
| | | | | | | | - Saravanan Shanmugam
- Department of Pharmacy, Federal University of Sergipe, São Cristóvão, Brazil
| | | | - Luiza Abrahão Frank
- Postgraduate Program in Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Mairim Russo Serafini
- Postgraduate Program in Health Sciences, Federal University of Sergipe, Aracaju, Brazil.,Department of Pharmacy, Federal University of Sergipe, São Cristóvão, Brazil.,Postgraduate Program in Pharmaceutical Sciences, Federal University of Sergipe, São Cristóvão, Brazil
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Li X, Chen Z, Jiao J, Wang S, Wang Y, Wu W, Yang H, Lou H. In vitro and in vivo activity of meropenem+avibactam against MBL-producing carbapenem-resistant Klebsiella pneumoniae. Expert Rev Anti Infect Ther 2023; 21:91-98. [PMID: 36433637 DOI: 10.1080/14787210.2022.2153117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Antibiotic resistance has become a public health problem to be solved worldwide and metallo-β-lactamase (MBL)-producing bacteria make this problem even more challenging. METHODS The interactions of meropenem (MEM) in combination with avibactam (AVI) in growth inhibition on MBL-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) strains were tested. In vitro interactions of MEM+AVI were tested using the microdilution checkerboard assay and time-kill curves. In vivo interactions of MEM+AVI were tested using the Galleria mellonella model. RESULTS All strains were multi-drug resistant strains and six of them were proved to produce MBLs. We show that the combination of MEM+AVI generates profound synergistic effects on growth inhibition of all strains, which was better than that of MEM+vaborbactam or imipenem+relebactam. The time-kill curves further confirmed the potent synergistic antibacterial effects of MEM+AVI against MBL-producing CRKP strains. Galleria mellonella studies were consistent with in vitro analysis. Combining MEM with AVI improved survival rates and mean survival days were obviously prolonged compared to the drug alone and the untreated controls. CONCLUSIONS To our knowledge, this study is the first report of MEM+AVI collaborating against MBL-producing CRKP strains. Our findings showed that the combination of MEM+AVI has the potential for antibiotic drug development to combat MBL-producing pathogens.
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Affiliation(s)
- Xiuyun Li
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.,Maternal and Child Health Development Research Center, Key Laboratory of Birth Regulation and Control Technology of National Health Commission of China, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, Shandong, China
| | - Zhaowen Chen
- Medical Department, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, Shandong, China
| | - Jin Jiao
- Department of Clinical Laboratory, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, Shandong, China
| | - Shifu Wang
- Microbiology Laboratory, Children's Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Yuehua Wang
- Department of Pharmacy, the Affiliated Hospital of Qingdao University, Qingdao, Shandong, China
| | - Weiwei Wu
- Department of Clinical Laboratory, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, Shandong, China
| | - Huijun Yang
- Reproductive Medicine Center, Shandong Provincial Maternal and Child Health Care Hospital Affiliated to Qingdao University, Jinan, Shandong, China
| | - Hongxiang Lou
- Department of Natural Product Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
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Moreno-Blanco A, Solano-Collado V, Ortuno-Camuñas A, Espinosa M, Ruiz-Cruz S, Bravo A. PclR is a transcriptional activator of the gene that encodes the pneumococcal collagen-like protein PclA. Sci Rep 2022; 12:11827. [PMID: 35821046 PMCID: PMC9276737 DOI: 10.1038/s41598-022-15758-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/29/2022] [Indexed: 11/09/2022] Open
Abstract
The Gram-positive bacterium Streptococcus pneumoniae is a major human pathogen that shows high levels of genetic variability. The pneumococcal R6 genome harbours several gene clusters that are not present in all strains of the species. One of these clusters contains two divergent genes, pclA, which encodes a putative surface-exposed protein that contains large regions of collagen-like repeats, and spr1404 (here named pclR). PclA was shown to mediate pneumococcal adherence to host cells in vitro. In this work, we demonstrate that PclR (494 amino acids) is a transcriptional activator. It stimulates transcription of the pclA gene by binding to a specific DNA site upstream of the core promoter. In addition, we show that PclR has common features with the MgaSpn transcriptional regulator (493 amino acids), which is also encoded by the R6 genome. These proteins have high sequence similarity (60.3%), share the same organization of predicted functional domains, and generate multimeric complexes on linear double-stranded DNAs. However, on the PpclA promoter region, MgaSpn binds to a site different from the one recognized by PclR. Our results indicate that PclR and MgaSpn have similar DNA-binding properties but different DNA-binding specificities, pointing to a different regulatory role of both proteins.
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Affiliation(s)
- Ana Moreno-Blanco
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Virtu Solano-Collado
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.,Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Alejandro Ortuno-Camuñas
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Sofía Ruiz-Cruz
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain. .,School of Microbiology, University College Cork and APC Microbiome Ireland, Western Road, Cork, T12 YT20, Ireland.
| | - Alicia Bravo
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040, Madrid, Spain.
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Miguel-Arribas A, Wu LJ, Michaelis C, Yoshida KI, Grohmann E, Meijer WJJ. Conjugation Operons in Gram-Positive Bacteria with and without Antitermination Systems. Microorganisms 2022; 10:microorganisms10030587. [PMID: 35336162 PMCID: PMC8955417 DOI: 10.3390/microorganisms10030587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 02/01/2023] Open
Abstract
Genes involved in the same cellular process are often clustered together in an operon whose expression is controlled by an upstream promoter. Generally, the activity of the promoter is strictly controlled. However, spurious transcription undermines this strict regulation, particularly affecting large operons. The negative effects of spurious transcription can be mitigated by the presence of multiple terminators inside the operon, in combination with an antitermination system. Antitermination systems modify the transcription elongation complexes and enable them to bypass terminators. Bacterial conjugation is the process by which a conjugative DNA element is transferred from a donor to a recipient cell. Conjugation involves many genes that are mostly organized in one or a few large operons. It has recently been shown that many conjugation operons present on plasmids replicating in Gram-positive bacteria possess a bipartite antitermination system that allows not only many terminators inside the conjugation operon to be bypassed, but also the differential expression of a subset of genes. Here, we show that some conjugation operons on plasmids belonging to the Inc18 family of Gram-positive broad host-range plasmids do not possess an antitermination system, suggesting that the absence of an antitermination system may have advantages. The possible (dis)advantages of conjugation operons possessing (or not) an antitermination system are discussed.
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Affiliation(s)
- Andrés Miguel-Arribas
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Instituto de Biología Molecular Eladio Viñuela (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain;
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Medical Faculty, Biosciences Institute, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, UK;
| | - Claudia Michaelis
- School of Life Sciences and Technology, Berlin University of Applied Sciences, Seestrasse 64, 13347 Berlin, Germany;
| | - Ken-ichi Yoshida
- Department of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan;
| | - Elisabeth Grohmann
- School of Life Sciences and Technology, Berlin University of Applied Sciences, Seestrasse 64, 13347 Berlin, Germany;
- Correspondence: (E.G.); (W.J.J.M.); Tel.: +49-30-4504-3942 (E.G.); +34-91-196-4539 (W.J.J.M.)
| | - Wilfried J. J. Meijer
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Instituto de Biología Molecular Eladio Viñuela (CSIC), C. Nicolás Cabrera 1, Universidad Autónoma, Canto Blanco, 28049 Madrid, Spain;
- Correspondence: (E.G.); (W.J.J.M.); Tel.: +49-30-4504-3942 (E.G.); +34-91-196-4539 (W.J.J.M.)
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Li Y, Zhang C, Mou X, Zhang P, Liang J, Wang Z. Distribution characteristics of antibiotic resistance bacteria and related genes in urban recreational lakes replenished by different supplementary water source. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2022; 85:1176-1190. [PMID: 35228362 DOI: 10.2166/wst.2022.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The distribution characteristics of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in urban recreational water from different water-supply sources might be different. In this study, water samples were collected to detect the antibiotic resistance of heterotrophic bacteria to five antibiotics, and the content, phenotype, gene type and species distribution of resistant bacteria were analyzed. The results showed that the changes of bacteria resistance rate in two lakes to five kinds of antibiotics were synchronous with time, and it would reach its maximum in autumn. The detection of ARGs and int I in 80 resistance strains showed that the detection rate of tetG, tetA and int I was high. Here, 51.25% of the bacteria were doubly resistant to AMP-CTX. The 80 isolate strains were of nine genera and 19 species, among which Bacillus cereus, Escherichia coli, Aeromonas veronii, Aeromonas caviae and Raoultella ornithinolytica were the common ARB species in two lakes. Correlation analysis showed that the water temperature was significantly correlated with the content of ARB in sulfamethoxazole (SMZ) and cefotaxime (CTX) (p < 0.05), and the total phosphorus (TP) in FQ lake was significantly correlated with the content of AMP-resistant bacteria (p < 0.05), while there were no other correlations between the changes of other water quality indexes and the content of ARB (p > 0.05).
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Affiliation(s)
- Yongqiang Li
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China E-mail: ; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Chongmiao Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China E-mail: ; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China; International Science and Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Xiao Mou
- Shaanxi Institute for Food and Drug Control, Xi'an, 710065, China
| | - Peipei Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China E-mail: ; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Jie Liang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China E-mail: ; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Zhen Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China E-mail: ; Key Lab of Northwest Water Resource, Environment and Ecology, Ministry of Education, Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
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The Facts and Family Secrets of Plasmids That Replicate via the Rolling-Circle Mechanism. Microbiol Mol Biol Rev 2021; 86:e0022220. [PMID: 34878299 DOI: 10.1128/mmbr.00222-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plasmids are self-replicative DNA elements that are transferred between bacteria. Plasmids encode not only antibiotic resistance genes but also adaptive genes that allow their hosts to colonize new niches. Plasmid transfer is achieved by conjugation (or mobilization), phage-mediated transduction, and natural transformation. Thousands of plasmids use the rolling-circle mechanism for their propagation (RCR plasmids). They are ubiquitous, have a high copy number, exhibit a broad host range, and often can be mobilized among bacterial species. Based upon the replicon, RCR plasmids have been grouped into several families, the best known of them being pC194 and pUB110 (Rep_1 family), pMV158 and pE194 (Rep_2 family), and pT181 and pC221 (Rep_trans family). Genetic traits of RCR plasmids are analyzed concerning (i) replication mediated by a DNA-relaxing initiator protein and its interactions with the cognate DNA origin, (ii) lagging-strand origins of replication, (iii) antibiotic resistance genes, (iv) mobilization functions, (v) replication control, performed by proteins and/or antisense RNAs, and (vi) the participating host-encoded functions. The mobilization functions include a relaxase initiator of transfer (Mob), an origin of transfer, and one or two small auxiliary proteins. There is a family of relaxases, the MOBV family represented by plasmid pMV158, which has been revisited and updated. Family secrets, like a putative open reading frame of unknown function, are reported. We conclude that basic research on RCR plasmids is of importance, and our perspectives contemplate the concept of One Earth because we should incorporate bacteria into our daily life by diminishing their virulence and, at the same time, respecting their genetic diversity.
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10
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Solano-Collado V, Ruiz-Cruz S, Lorenzo-Díaz F, Pluta R, Espinosa M, Bravo A. Recognition of Streptococcal Promoters by the Pneumococcal SigA Protein. Front Mol Biosci 2021; 8:666504. [PMID: 34250014 PMCID: PMC8264293 DOI: 10.3389/fmolb.2021.666504] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/14/2021] [Indexed: 11/13/2022] Open
Abstract
Promoter recognition by RNA polymerase is a key step in the regulation of gene expression. The bacterial RNA polymerase core enzyme is a complex of five subunits that interacts transitory with one of a set of sigma factors forming the RNA polymerase holoenzyme. The sigma factor confers promoter specificity to the RNA polymerase. In the Gram-positive pathogenic bacterium Streptococcus pneumoniae, most promoters are likely recognized by SigA, a poorly studied housekeeping sigma factor. Here we present a sequence conservation analysis and show that SigA has similar protein architecture to Escherichia coli and Bacillus subtilis homologs, namely the poorly conserved N-terminal 100 residues and well-conserved rest of the protein (domains 2, 3, and 4). Further, we have purified the native (untagged) SigA protein encoded by the pneumococcal R6 strain and reconstituted an RNA polymerase holoenzyme composed of the E. coli core enzyme and the sigma factor SigA (RNAP-SigA). By in vitro transcription, we have found that RNAP-SigA was able to recognize particular promoters, not only from the pneumococcal chromosome but also from the S. agalactiae promiscuous antibiotic-resistance plasmid pMV158. Specifically, SigA was able to direct the RNA polymerase to transcribe genes involved in replication and conjugative mobilization of plasmid pMV158. Our results point to the versatility of SigA in promoter recognition and its contribution to the promiscuity of plasmid pMV158.
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Affiliation(s)
| | - Sofía Ruiz-Cruz
- School of Microbiology, University College Cork, Cork, Ireland
| | - Fabián Lorenzo-Díaz
- Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Universidad de La Laguna, Tenerife, Spain
| | - Radoslaw Pluta
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Alicia Bravo
- Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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11
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Yin B, Umar T, Ma X, Chen Y, Chen N, Wu Z, Deng G. MiR-193a-3p targets LGR4 to promote the inflammatory response in endometritis. Int Immunopharmacol 2021; 98:107718. [PMID: 34139630 DOI: 10.1016/j.intimp.2021.107718] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/17/2021] [Accepted: 04/21/2021] [Indexed: 01/02/2023]
Abstract
Solving the reproductive barriers of dairy cows has become one of the most critical factors determining the dairy industry's development. Clinically, inflammation disease like endometritis is the most crucial cause in reducing dairy production's financial viability. MiR-193 family can induce cell apoptosis and differentiation has been reported in various diseases. LGR4 plays a vital role in reproductive system development and immune system regulation, and it is closely related to animal reproductive function and cytokine regulation. In this study, we observed a negative relationship between miR-193a-3p and LGR4 expression level in both inflammatory tissues and cells. The expression level of miR-193a-3p and LGR4 in bovine endometrial epithelial cells (BENDs) is regulated by lipopolysaccharide (LPS) stimulation time and dose-dependent. Subsequently, miR-193a-3p mimics and inhibitors were used to explore its functions in the inflammation response process, finding that overexpression of miR-193a-3p markedly increases the expression level of pro-inflammatory cytokines induced by LPS, such as IL-1β, IL-6 and TNF-α, while the group in which transfected inhibitor is on the contrary. Of note, immunofluorescence and western blot results showed that miR-193a-3p enhanced LPS-induced NF-κB p65 phosphorylation through targeting LGR4, whereas inhibiting miR-193a-3p could suppress the activation of NF-κB pathway significantly. In conclusion, our study firstly reported the mechanism by which miR-193a-3p targets LGR4 to elevate the inflammatory response in bovine endometrium injury, thereby implying that knockdown miR-193a-3p may lay the theoretical and practical basis for drug development of alleviating endometritis in dairy cows.
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Affiliation(s)
- Baoyi Yin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Talha Umar
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Xiaofei Ma
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Yu Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Nuoer Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Zhimin Wu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Ganzhen Deng
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China.
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12
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Akeda Y. Current situation of carbapenem-resistant Enterobacteriaceae and Acinetobacter in Japan and Southeast Asia. Microbiol Immunol 2021; 65:229-237. [PMID: 33913535 DOI: 10.1111/1348-0421.12887] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/18/2021] [Accepted: 04/21/2021] [Indexed: 11/30/2022]
Abstract
In the recent years, issues related to drug-resistant bacteria have evolved worldwide, and various countermeasures have been taken to control their spread. Among a wide variety of drug-resistant bacterial species, carbapenem-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Acinetobacter baumannii (CRAb), are those for which countermeasures are particularly important. Carbapenems are the last resort antibiotics for any bacterial infection; therefore, infectious diseases caused by these drug-resistant bacteria are difficult to treat. In the case of CRE, since carbapenemases responsible for carbapenem resistance are mostly encoded on transmissible plasmids, it is known that susceptible bacteria can easily become carbapenem-resistant by transfer of plasmids between Enterobacteriaceae. In addition, Enterobacteriaceae are common bacterial species found in the guts of animals, including humans. Acinetobacter is ubiquitously isolated in the environment. Due to these characteristics, it is quite difficult to prevent the intrusion of multi-drug resistant pathogens in hospitals. Therefore, effective countermeasures should be developed and utilized against such dangerous pathogens based on molecular epidemiological analyses. In this review, there are also some examples presented on how to manage to monitor and control those troublesome drug-resistant bacteria conducted in Japan and Southeast Asia.
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Affiliation(s)
- Yukihiro Akeda
- Division of Infection Control and Prevention, Osaka University Hospital, Osaka University, Osaka, Japan.,Department of Infection Control and Prevention, Graduate School of Medicine, Osaka University, Osaka, Japan.,Japan-Thailand Research Collaboration Center on Emerging and Re-emerging Infections, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
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13
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Liu S, Wang T, Lu Q, Li F, Wu G, Jiang Z, Habden X, Liu L, Zhang X, Lukianov DA, Osterman IA, Sergiev PV, Dontsova OA, Sun C. Bioprospecting of Soil-Derived Actinobacteria Along the Alar-Hotan Desert Highway in the Taklamakan Desert. Front Microbiol 2021; 12:604999. [PMID: 33790875 PMCID: PMC8005632 DOI: 10.3389/fmicb.2021.604999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/22/2021] [Indexed: 02/04/2023] Open
Abstract
Taklamakan desert is known as the largest dunefield in China and as the second largest shifting sand desert in the world. Although with long history and glorious culture, the Taklamakan desert remains largely unexplored and numerous microorganisms have not been harvested in culture or taxonomically identified yet. The main objective of this study is to explore the diversity, novelty, and pharmacological potential of the cultivable actinomycetes from soil samples at various sites along the Alar-Hotan desert highway in the Taklamakan desert. A total of 590 actinobacterial strains were recovered by the culture-dependent approach. Phylogenetic analysis based on 16S ribosomal RNA (rRNA) gene sequences unveiled a significant level of actinobacterial diversity with 55 genera distributed in 27 families of 12 orders. Thirty-six strains showed relatively low 16S rRNA similarities (<98.65%) with validly described species, among which four strains had already been characterized as novel taxa by our previous research. One hundred and forty-six actinobacterial isolates were selected as representatives to evaluate the antibacterial activities and mechanism of action by the paper-disk diffusion method and a double fluorescent protein reporter "pDualrep2" system, respectively. A total of 61 isolates exhibited antagonistic activity against the tested "ESKAPE" pathogens, among which seven strains could produce bioactive metabolites either to be able to block translation machinery or to induce SOS-response in the pDualrep2 system. Notably, Saccharothrix sp. 16Sb2-4, harboring a promising antibacterial potential with the mechanism of interfering with protein translation, was analyzed in detail to gain deeper insights into its bioactive metabolites. Through ultra-performance liquid chromatography (UPLC)-quadrupole time-of-flight (QToF)-MS/MS based molecular networking analysis and databases identification, four families of compounds (1-16) were putatively identified. Subsequent bioassay-guided separation resulted in purification of four 16-membered macrolide antibiotics, aldgamycin H (8), aldgamycin K (9), aldgamycin G (10), and swalpamycin B (11), and their structures were elucidated by HR-electrospray ionization source (ESI)-MS and NMR spectroscopy. All compounds 8-11 displayed antibacterial activities by inhibiting protein synthesis in the pDualrep2 system. In conclusion, this work demonstrates that Taklamakan desert is a potentially unique reservoir of versatile actinobacteria, which can be a promising source for discovery of novel species and diverse bioactive compounds.
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Affiliation(s)
- Shaowei Liu
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ting Wang
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Qinpei Lu
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Feina Li
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Gang Wu
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Zhongke Jiang
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xugela Habden
- College of Life Science, Xinjiang Normal University, Urumchi, China
| | - Lin Liu
- School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Xiaolin Zhang
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, China
| | - Dmitry A. Lukianov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Ilya A. Osterman
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Department of Chemistry, A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Petr V. Sergiev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Department of Chemistry, A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Olga A. Dontsova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
- Department of Chemistry, A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Chenghang Sun
- Department of Microbial Chemistry, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- 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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Delvaux C, Dauvin M, Boulanger M, Quinton L, Mengin-Lecreulx D, Joris B, Pauw ED, Far J. Use of Capillary Zone Electrophoresis Coupled to Electrospray Mass Spectrometry for the Detection and Absolute Quantitation of Peptidoglycan-Derived Peptides in Bacterial Cytoplasmic Extracts. Anal Chem 2021; 93:2342-2350. [PMID: 33470796 DOI: 10.1021/acs.analchem.0c04218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptidoglycan (PGN) is an essential structure found in the bacterial cell wall. During the bacterial life cycle, PGN continuously undergoes biosynthesis and degradation to ensure bacterial growth and division. The resulting PGN fragments (muropeptides and peptides), which are generated by the bacterial autolytic system, are usually transported into the cytoplasm to be recycled. On the other hand, PGN fragments can act as messenger molecules involved in the bacterial cell wall stress response as in the case of β-lactamase induction in the presence of β-lactam antibiotic or in triggering mammalian innate immune response. During their cellular life, bacteria modulate their PGN degradation by their autolytic system or their recognition by the mammalian innate immune system by chemically modifying their PGN. Among these modifications, the amidation of the ε-carboxyl group of meso-diaminopimelic acid present in the PGN peptide chain is frequently observed. Currently, the detection and quantitation of PGN-derived peptides is still challenging because of the difficulty in separating these highly hydrophilic molecules by RP-HPLC as these compounds are eluted closely after the column void volume or coeluted in many cases. Here, we report the use of capillary zone electrophoresis coupled via an electrospray-based CE-MS interface to high-resolution mass spectrometry for the quantitation of three PGN peptides of interest and their amidated derivatives in bacterial cytoplasmic extracts. The absolute quantitation of the tripeptide based on the [13C,15N] isotopically labeled standard was also performed in crude cytoplasmic extracts of bacteria grown in the presence or absence of a β-lactam antibiotic (cephalosporin C). Despite the high complexity of the samples, the repeatability of the CZE-MS quantitation results was excellent, with relative standard deviations close to 1%. The global reproducibility of the method including biological handling was better than 20%.
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Affiliation(s)
- Cédric Delvaux
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Marjorie Dauvin
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Madeleine Boulanger
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Bernard Joris
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
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15
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Characterization of permissive and non-permissive peptide insertion sites in chloramphenicol acetyltransferase. Microb Pathog 2020; 149:104395. [DOI: 10.1016/j.micpath.2020.104395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/02/2020] [Accepted: 07/10/2020] [Indexed: 12/11/2022]
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16
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Targeting Type II Toxin-Antitoxin Systems as Antibacterial Strategies. Toxins (Basel) 2020; 12:toxins12090568. [PMID: 32899634 PMCID: PMC7551001 DOI: 10.3390/toxins12090568] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022] Open
Abstract
The identification of novel targets for antimicrobial agents is crucial for combating infectious diseases caused by evolving bacterial pathogens. Components of bacterial toxin–antitoxin (TA) systems have been recognized as promising therapeutic targets. These widespread genetic modules are usually composed of two genes that encode a toxic protein targeting an essential cellular process and an antitoxin that counteracts the activity of the toxin. Uncontrolled toxin expression may elicit a bactericidal effect, so they may be considered “intracellular molecular bombs” that can lead to elimination of their host cells. Based on the molecular nature of antitoxins and their mode of interaction with toxins, TA systems have been classified into six groups. The most prevalent are type II TA systems. Due to their ubiquity among clinical isolates of pathogenic bacteria and the essential processes targeted, they are promising candidates for the development of novel antimicrobial strategies. In this review, we describe the distribution of type II TA systems in clinically relevant human pathogens, examine how these systems could be developed as the targets for novel antibacterials, and discuss possible undesirable effects of such therapeutic intervention, such as the induction of persister cells, biofilm formation and toxicity to eukaryotic cells.
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17
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Lorenzo-Diaz F, Moreno-Córdoba I, Espinosa M. Complete labelling of pneumococcal DNA-binding proteins with seleno-L-methionine. J Microbiol Methods 2019; 166:105720. [PMID: 31518592 DOI: 10.1016/j.mimet.2019.105720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 10/26/2022]
Abstract
Streptococcus pneumoniae is a pathogenic and opportunistic Gram-positive bacterium that is the leading cause of community-acquired respiratory diseases, varying from mild- to deathly- infections. The appearance of antibiotic-resistant isolates has prompted the search for novel strategies and targets to tackle the bacterial resistances. One of the most promising approaches is the structure-based knowledge of possible targets in conjunction with rational design and docking of inhibitors of the chosen targets. A useful technique that helps to solve protein structures is to label them with an amino acid derivative like seleno-methionine that facilitates tracing of some of the amino acid residues. We have chosen two pneumococcal DNA-binding proteins, namely the relaxase domain of MobM protein from plasmid pMV158, and the RelB-RelE antitoxin-toxin protein complex. Through several changes that improve substantially a previous protocol (Budisa et al., 1995), we have used seleno-L-methionine to incorporate selenium into the amino acid sequence of the selected proteins. We have achieved 100% labelling of the proteins and could demonstrate that the labelled proteins retained full activity as judged from the relaxation of supercoiled plasmid DNA and from gel-retardation assays.
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Affiliation(s)
- Fabián Lorenzo-Diaz
- Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Universidad de La Laguna, Santa Cruz de Tenerife, Spain
| | - Inmaculada Moreno-Córdoba
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Manuel Espinosa
- Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu, 9, 28040 Madrid, Spain.
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