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Shi X, Xia Y, Wei W, Ni BJ. Accelerated spread of antibiotic resistance genes (ARGs) induced by non-antibiotic conditions: Roles and mechanisms. WATER RESEARCH 2022; 224:119060. [PMID: 36096030 DOI: 10.1016/j.watres.2022.119060] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/28/2022] [Accepted: 09/04/2022] [Indexed: 05/28/2023]
Abstract
The global spread of antibiotic resistance genes (ARGs) has wreaked havoc with the treatment efficiency of antibiotics and, ultimately, anti-microbial chemotherapy, and has been conventionally attributed to the abuse and misuse of antibiotics. However, the ancient ARGs have alterative functions in bacterial physiology and thus they could be co-regulated by non-antibiotic conditions. Recent research has demonstrated that many non-antibiotic chemicals such as microplastics, metallic nanoparticles and non-antibiotic drugs, as well as some non-antibiotic conditions, can accelerate the dissemination of ARGs. These results suggested that the role of antibiotics might have been previously overestimated whereas the effects of non-antibiotic conditions were possibly ignored. Thus, in an attempt to fully understand the fate and behavior of ARGs in the eco-system, it is urgent to critically highlight the role and mechanisms of non-antibiotic chemicals and related environmental factors in the spread of ARGs. To this end, this timely review assessed the evolution of ARGs, especially its function alteration, summarized the non-antibiotic chemicals promoting the spread of ARGs, evaluated the non-antibiotic conditions related to ARG dissemination and analyzed the molecular mechanisms related to spread of ARGs induced by the non-antibiotic factors. Finally, this review then provided several critical perspectives for future research.
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Affiliation(s)
- Xingdong Shi
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Yu Xia
- School of Environmental Science and Engineering, College of Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wei Wei
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, Sydney, NSW 2007, Australia.
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2
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Yin CM, Pan XY, Cao XT, Li T, Zhang YH, Lan JF. A crayfish ALF inhibits the proliferation of microbiota by binding to RPS4 and MscL of E. coli. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 121:104106. [PMID: 33878364 DOI: 10.1016/j.dci.2021.104106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
Antimicrobial peptides (AMPs), most of which are small proteins, are necessary for innate immunity against pathogens. Anti-lipopolysaccharide factor (ALF) with a conserved lipopolysaccharide binding domain (LBD) can bind to lipopolysaccharide (LPS) and neutralize LPS activity. The antibacterial mechanism of ALF, especially its role in bacteria, needs to be further investigated. In this study, the antibacterial role of an anti-lipopolysaccharide factor (PcALF5) derived from Procambarus clarkii was analyzed. PcALF5 could inhibit the replication of the microbiota in vitro and enhance the bacterial clearance ability in crayfish in vivo. Far-western blot assay results indicated that PcALF5 bound to two proteins of E. coli (approximately 25 kDa and 15 kDa). Mass spectrometry (MS), far-western blot assay, and pull-down results showed that 30S ribosomal protein S4 (RPS4, 25 kD) interacted with PcALF5. Further studies revealed that another E. coli protein binding to PcALF5 could be the large mechanosensitive channel (MscL), which is reported to participate in the transport of peptides and antibiotics. Additional assays showed that PcALF5 inhibited protein synthesis and promoted the transcription of ribosomal component genes in E. coli. Overall, these results indicate that PcALF5 could transfer into E. coli by binding to MscL and inhibit protein synthesis by interacting with RPS4. This study reveals the mechanism underlying ALF involvement in the antibacterial immune response and provides a new reference for the research on antibacterial drugs.
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Affiliation(s)
- Cheng-Ming Yin
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiao-Yi Pan
- Agriculture Ministry Key Laboratory of Healthy Freshwater Aquaculture, Key Laboratory of Freshwater Aquaculture Genetic and Breeding of Zhejiang Province, Zhejiang Institute of Freshwater Fisheries, Huzhou, 313001, China
| | - Xiao-Tong Cao
- Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, 271018, China
| | - Tong Li
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ying-Hao Zhang
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Jiang-Feng Lan
- College of Fisheries, Huazhong Agricultural University, Wuhan, 430070, China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Taian, 271018, China.
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3
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Grenade NL, Howe GW, Ross AC. The convergence of bacterial natural products from evolutionarily distinct pathways. Curr Opin Biotechnol 2020; 69:17-25. [PMID: 33296737 DOI: 10.1016/j.copbio.2020.10.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/21/2020] [Accepted: 10/05/2020] [Indexed: 10/22/2022]
Abstract
As bacteria readily convert simple starting materials into a diverse array of complex molecules with useful bioactivities, these microorganisms and their biosynthetic machinery represent attractive alternatives to traditional chemical syntheses. While the well-documented divergent evolution of biosynthesis has allowed bacteria to explore wide swaths of natural product chemical space, the convergent evolution of these pathways remains a comparably rare phenomenon. The emergence of similar phenotypes within disparate genetic contexts provides a unique opportunity to probe the limitations of natural selection and the predictability and reproducibility of evolution under different constraints. Here, we report several recent examples of functional and structural convergence of bacterial natural products, as well as intra- and inter-domain convergence of bacterial biosynthetic machinery. While the genetic underpinnings of biosynthetic pathway evolution are of fundamental interest, the evolutionary constraints exemplified by phenotypic convergence also have immediate implications for efforts to engineer microorganisms for therapeutic small molecule production.
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Affiliation(s)
- Neil L Grenade
- Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Graeme W Howe
- Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Avena C Ross
- Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada.
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4
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Xia H, Li X, Li Z, Zhan X, Mao X, Li Y. The Application of Regulatory Cascades in Streptomyces: Yield Enhancement and Metabolite Mining. Front Microbiol 2020; 11:406. [PMID: 32265866 PMCID: PMC7105598 DOI: 10.3389/fmicb.2020.00406] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 02/26/2020] [Indexed: 12/13/2022] Open
Abstract
Streptomyces is taken as an important resource for producing the most abundant antibiotics and other bio-active natural products, which have been widely used in pharmaceutical and agricultural areas. Usually they are biosynthesized through secondary metabolic pathways encoded by cluster situated genes. And these gene clusters are stringently regulated by interweaved transcriptional regulatory cascades. In the past decades, great advances have been made to elucidate the regulatory mechanisms involved in antibiotic production in Streptomyces. In this review, we summarized the recent advances on the regulatory cascades of antibiotic production in Streptomyces from the following four levels: the signals triggering the biosynthesis, the global regulators, the pathway-specific regulators and the feedback regulation. The production of antibiotic can be largely enhanced by rewiring the regulatory networks, such as overexpression of positive regulators, inactivation of repressors, fine-tuning of the feedback and ribosomal engineering in Streptomyces. The enormous amount of genomic sequencing data implies that the Streptomyces has potential to produce much more antibiotics for the great diversities and wide distributions of biosynthetic gene clusters in Streptomyces genomes. Most of these gene clusters are defined cryptic for unknown or undetectable natural products. In the synthetic biology era, activation of the cryptic gene clusters has been successfully achieved by manipulation of the regulatory genes. Chemical elicitors, rewiring regulatory gene and ribosomal engineering have been employed to crack the potential of cryptic gene clusters. These have been proposed as the most promising strategy to discover new antibiotics. For the complex of regulatory network in Streptomyces, we proposed that the discovery of new antibiotics and the optimization of industrial strains would be greatly promoted by further understanding the regulatory mechanism of antibiotic production.
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Affiliation(s)
- Haiyang Xia
- Institute of Biopharmaceuticals, Taizhou University, Taizhou, China
| | - Xiaofang Li
- Institute of Biopharmaceuticals, Taizhou University, Taizhou, China
| | - Zhangqun Li
- Institute of Biopharmaceuticals, Taizhou University, Taizhou, China
| | - Xinqiao Zhan
- Institute of Biopharmaceuticals, Taizhou University, Taizhou, China
| | - Xuming Mao
- Institute of Biopharmaceuticals, Taizhou University, Taizhou, China.,Institute of Pharmaceutical Biotechnology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yongquan Li
- Institute of Biopharmaceuticals, Taizhou University, Taizhou, China.,Institute of Pharmaceutical Biotechnology, School of Medicine, Zhejiang University, Hangzhou, China
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5
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Lopatniuk M, Myronovskyi M, Nottebrock A, Busche T, Kalinowski J, Ostash B, Fedorenko V, Luzhetskyy A. Effect of “ribosome engineering” on the transcription level and production of S. albus indigenous secondary metabolites. Appl Microbiol Biotechnol 2019; 103:7097-7110. [DOI: 10.1007/s00253-019-10005-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 06/11/2019] [Accepted: 06/30/2019] [Indexed: 01/31/2023]
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6
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Microbial evolutionary medicine: from theory to clinical practice. THE LANCET. INFECTIOUS DISEASES 2019; 19:e273-e283. [PMID: 31053492 DOI: 10.1016/s1473-3099(19)30045-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/21/2018] [Accepted: 02/04/2019] [Indexed: 12/15/2022]
Abstract
Medicine and clinical microbiology have traditionally attempted to identify and eliminate the agents that cause disease. However, this traditional approach is becoming inadequate for dealing with a changing disease landscape. Major challenges to human health are non-communicable chronic diseases, often driven by altered immunity and inflammation, and communicable infections from agents which harbour antibiotic resistance. This Review focuses on the so-called evolutionary medicine framework, to study how microbial communities influence human health. The evolutionary medicine framework aims to predict and manipulate microbial effects on human health by integrating ecology, evolutionary biology, microbiology, bioinformatics, and clinical expertise. We focus on the potential of evolutionary medicine to address three key challenges: detecting microbial transmission, predicting antimicrobial resistance, and understanding microbe-microbe and human-microbe interactions in health and disease, in the context of the microbiome.
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7
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Quandt EM, Traverse CC, Ochman H. Local genic base composition impacts protein production and cellular fitness. PeerJ 2018; 6:e4286. [PMID: 29362699 PMCID: PMC5774297 DOI: 10.7717/peerj.4286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/01/2018] [Indexed: 01/25/2023] Open
Abstract
The maintenance of a G + C content that is higher than the mutational input to a genome provides support for the view that selection serves to increase G + C contents in bacteria. Recent experimental evidence from Escherichia coli demonstrated that selection for increasing G + C content operates at the level of translation, but the precise mechanism by which this occurs is unknown. To determine the substrate of selection, we asked whether selection on G + C content acts across all sites within a gene or is confined to particular genic regions or nucleotide positions. We systematically altered the G + C contents of the GFP gene and assayed its effects on the fitness of strains harboring each variant. Fitness differences were attributable to the base compositional variation in the terminal portion of the gene, suggesting a connection to the folding of a specific protein feature. Variants containing sequence features that are thought to result in rapid translation, such as low G + C content and high levels of codon adaptation, displayed highly reduced growth rates. Taken together, our results show that purifying selection acting against A and T mutations most likely results from their tendency to increase the rate of translation, which can perturb the dynamics of protein folding.
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Affiliation(s)
- Erik M Quandt
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
| | - Charles C Traverse
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
| | - Howard Ochman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, United States of America
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8
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Xu Z, Xu X, Qi D, Yang L, Li B, Li L, Li X, Chen D. Effect of aminoglycosides on the pathogenic characteristics of microbiology. Microb Pathog 2017; 113:357-364. [PMID: 28867624 DOI: 10.1016/j.micpath.2017.08.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 02/08/2023]
Abstract
Infections caused by pathogen remain to be one of the most important global health issues, and scientists are devoting themselves to seeking effective treatments. Aminoglycoside antibiotics are one kind of widely used antibiotics because of the good efficiency and broad antimicrobial-spectrum. However, it causes some unexpected effects on the pathogenic characteristics of microbiology during the treatment, such as drug resistance and biofilm promotion. Drug resistance is partly due to antibiotics abuse. Simultaneously, aminoglycoside is documented to make divergent effects on biofilm based on their concentrations. Here, we review the mechanism of drug resistance caused by long-term use of aminoglycoside antibiotics, the effects of antibiotic concentration on biofilm formation and the negative effects on intestinal flora to provide theoretical supports for rational use of antibiotics.
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Affiliation(s)
- Zhenbo Xu
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou, PR China; Department of Microbial Pathogenesis, School of Dentistry, University of Maryland, Baltimore, MD 21201, USA.
| | - Xingyong Xu
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, PR China
| | - Da Qi
- BGI-Shenzhen, Shenzhen 518083, PR China
| | - Ling Yang
- Department of Laboratory Medicine, First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510120, PR China
| | - Bing Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou, PR China
| | - Lin Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou, PR China
| | - Xiaoxi Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, PR China; Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, Guangzhou, PR China.
| | - Dingqiang Chen
- Department of Laboratory Medicine, First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou 510120, PR China
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9
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Evolution of Cost-Free Resistance under Fluctuating Drug Selection in Pseudomonas aeruginosa. mSphere 2017; 2:mSphere00158-17. [PMID: 28744479 PMCID: PMC5518267 DOI: 10.1128/msphere.00158-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/16/2017] [Indexed: 12/29/2022] Open
Abstract
Antibiotic resistance is a global problem that greatly impacts human health. How resistance persists, even in the absence of antibiotic treatment, is thus a public health problem of utmost importance. In this study, we explored the antibiotic treatment conditions under which cost-free resistance arises, using experimental evolution of the bacterium Pseudomonas aeruginosa and the quinolone antibiotic ciprofloxacin. We found that intermittent antibiotic treatment led to the evolution of cost-free resistance and demonstrate that compensatory evolution is the mechanism responsible for cost-free resistance. Our results suggest that discontinuous administration of antibiotic may be contributing to the high levels of antibiotic resistance currently found worldwide. Antibiotic resistance evolves rapidly in response to drug selection, but it can also persist at appreciable levels even after the removal of the antibiotic. This suggests that many resistant strains can both be resistant and have high fitness in the absence of antibiotics. To explore the conditions under which high-fitness, resistant strains evolve and the genetic changes responsible, we used a combination of experimental evolution and whole-genome sequencing to track the acquisition of ciprofloxacin resistance in the opportunistic pathogen Pseudomonas aeruginosa under conditions of constant and fluctuating antibiotic delivery patterns. We found that high-fitness, resistant strains evolved readily under fluctuating but not constant antibiotic conditions and that their evolution was underlain by a trade-off between resistance and fitness. Whole-genome sequencing of evolved isolates revealed that resistance was gained through mutations in known resistance genes and that second-site mutations generally compensated for costs associated with resistance in the fluctuating treatment, leading to the evolution of cost-free resistance. Our results suggest that current therapies involving intermittent administration of antibiotics are contributing to the maintenance of antibiotic resistance at high levels in clinical settings. IMPORTANCE Antibiotic resistance is a global problem that greatly impacts human health. How resistance persists, even in the absence of antibiotic treatment, is thus a public health problem of utmost importance. In this study, we explored the antibiotic treatment conditions under which cost-free resistance arises, using experimental evolution of the bacterium Pseudomonas aeruginosa and the quinolone antibiotic ciprofloxacin. We found that intermittent antibiotic treatment led to the evolution of cost-free resistance and demonstrate that compensatory evolution is the mechanism responsible for cost-free resistance. Our results suggest that discontinuous administration of antibiotic may be contributing to the high levels of antibiotic resistance currently found worldwide.
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10
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The ribosome as a missing link in prebiotic evolution II: Ribosomes encode ribosomal proteins that bind to common regions of their own mRNAs and rRNAs. J Theor Biol 2016; 397:115-27. [DOI: 10.1016/j.jtbi.2016.02.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 02/16/2016] [Accepted: 02/19/2016] [Indexed: 11/18/2022]
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11
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Singh AK, Drolia R, Bai X, Bhunia AK. Streptomycin Induced Stress Response in Salmonella enterica Serovar Typhimurium Shows Distinct Colony Scatter Signature. PLoS One 2015; 10:e0135035. [PMID: 26252374 PMCID: PMC4529181 DOI: 10.1371/journal.pone.0135035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 07/16/2015] [Indexed: 11/18/2022] Open
Abstract
We investigated the streptomycin-induced stress response in Salmonella enterica serovars with a laser optical sensor, BARDOT (bacterial rapid detection using optical scattering technology). Initially, the top 20 S. enterica serovars were screened for their response to streptomycin at 100 μg/mL. All, but four S. enterica serovars were resistant to streptomycin. The MIC of streptomycin-sensitive serovars (Enteritidis, Muenchen, Mississippi, and Schwarzengrund) varied from 12.5 to 50 μg/mL, while streptomycin-resistant serovar (Typhimurium) from 125–250 μg/mL. Two streptomycin-sensitive serovars (Enteritidis and Mississippi) were grown on brain heart infusion (BHI) agar plates containing sub-inhibitory concentration of streptomycin (1.25–5 μg/mL) and a streptomycin-resistant serovar (Typhimurium) was grown on BHI containing 25–50 μg/mL of streptomycin and the colonies (1.2 ± 0.1 mm diameter) were scanned using BARDOT. Data show substantial qualitative and quantitative differences in the colony scatter patterns of Salmonella grown in the presence of streptomycin than the colonies grown in absence of antibiotic. Mass-spectrometry identified overexpression of chaperonin GroEL, which possibly contributed to the observed differences in the colony scatter patterns. Quantitative RT-PCR and immunoassay confirmed streptomycin-induced GroEL expression while, aminoglycoside adenylyltransferase (aadA), aminoglycoside efflux pump (aep), multidrug resistance subunit acrA, and ribosomal protein S12 (rpsL), involved in streptomycin resistance, were unaltered. The study highlights suitability of the BARDOT as a non-invasive, label-free tool for investigating stress response in Salmonella in conjunction with the molecular and immunoassay methods.
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Affiliation(s)
- Atul K. Singh
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Rishi Drolia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Xingjian Bai
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
| | - Arun K. Bhunia
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America
- Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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12
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Rovner AJ, Haimovich AD, Katz SR, Li Z, Grome MW, Gassaway BM, Amiram M, Patel JR, Gallagher RR, Rinehart J, Isaacs FJ. Recoded organisms engineered to depend on synthetic amino acids. Nature 2015; 518:89-93. [PMID: 25607356 PMCID: PMC4590768 DOI: 10.1038/nature14095] [Citation(s) in RCA: 235] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 11/17/2014] [Indexed: 01/21/2023]
Abstract
Genetically modified organisms (GMOs) are increasingly used in research and industrial systems to produce high-value pharmaceuticals, fuels, and chemicals1. Genetic isolation and intrinsic biocontainment would provide essential biosafety measures to secure these closed systems and enable safe applications of GMOs in open systems2,3, which include bioremediation4 and probiotics5. Although safeguards have been designed to control cell growth by essential gene regulation6, inducible toxin switches7, and engineered auxotrophies8, these approaches are compromised by cross-feeding of essential metabolites, leaked expression of essential genes, or genetic mutations9,10. Here, we describe the construction of a series of genomically recoded organisms (GROs)11 whose growth is restricted by the expression of multiple essential genes that depend on exogenously supplied synthetic amino acids (sAAs). We introduced a Methanocaldococcus jannaschii tRNA:aminoacyl-tRNA synthetase (aaRS) pair into the chromosome of a GRO that lacks all TAG codons and release factor 1, endowing this organism with the orthogonal translational components to convert TAG into a dedicated sense codon for sAAs. Using multiplex automated genome engineering (MAGE)12, we introduced in-frame TAG codons into 22 essential genes, linking their expression to the incorporation of synthetic phenylalanine-derived amino acids. Of the 60 sAA-dependent variants isolated, a notable strain harboring 3 TAG codons in conserved functional residues13 of MurG, DnaA and SerS and containing targeted tRNA deletions maintained robust growth and exhibited undetectable escape frequencies upon culturing ∼1011 cells on solid media for seven days or in liquid media for 20 days. This is a significant improvement over existing biocontainment approaches2,3,6-10. We constructed synthetic auxotrophs dependent on sAAs that were not rescued by cross-feeding in environmental growth assays. These auxotrophic GROs possess alternate genetic codes that impart genetic isolation by impeding horizontal gene transfer11 and now depend on the use of synthetic biochemical building blocks, advancing orthogonal barriers between engineered organisms and the environment.
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Affiliation(s)
- Alexis J Rovner
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Adrian D Haimovich
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Spencer R Katz
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Zhe Li
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Michael W Grome
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Brandon M Gassaway
- 1] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA [2] Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut 06520, USA
| | - Miriam Amiram
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Jaymin R Patel
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Ryan R Gallagher
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
| | - Jesse Rinehart
- 1] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA [2] Department of Cellular and Molecular Physiology, Yale University, New Haven, Connecticut 06520, USA
| | - Farren J Isaacs
- 1] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA [2] Systems Biology Institute, Yale University, West Haven, Connecticut 06516, USA
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13
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Melnyk AH, Wong A, Kassen R. The fitness costs of antibiotic resistance mutations. Evol Appl 2014; 8:273-83. [PMID: 25861385 PMCID: PMC4380921 DOI: 10.1111/eva.12196] [Citation(s) in RCA: 351] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023] Open
Abstract
Antibiotic resistance is increasing in pathogenic microbial populations and is thus a major threat to public health. The fate of a resistance mutation in pathogen populations is determined in part by its fitness. Mutations that suffer little or no fitness cost are more likely to persist in the absence of antibiotic treatment. In this review, we performed a meta-analysis to investigate the fitness costs associated with single mutational events that confer resistance. Generally, these mutations were costly, although several drug classes and species of bacteria on average did not show a cost. Further investigations into the rate and fitness values of compensatory mutations that alleviate the costs of resistance will help us to better understand both the emergence and management of antibiotic resistance in clinical settings.
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Affiliation(s)
- Anita H Melnyk
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa Ottawa, ON, Canada
| | - Alex Wong
- Department of Biology, Carleton University Ottawa, ON, Canada
| | - Rees Kassen
- Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa Ottawa, ON, Canada
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14
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Pelchovich G, Nadejda S, Dana A, Tuller T, Bravo IG, Gophna U. Ribosomal mutations affecting the translation of genes that use non-optimal codons. FEBS J 2014; 281:3701-18. [PMID: 24966114 DOI: 10.1111/febs.12892] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 06/10/2014] [Accepted: 06/23/2014] [Indexed: 01/26/2023]
Abstract
Genes that are laterally acquired by a new host species often contain codons that are non-optimal to the tRNA repertoire of the new host, which may lead to insufficient translational levels. Inefficient translation can be overcome by different mechanisms, such as incremental amelioration of the coding sequence, compensatory mutations in the regulatory sequences leading to increased transcription or increase in gene copy number. However, there is also a possibility that ribosomal mutations can improve the expression of such genes. To test this hypothesis, we examined the effects of point mutations in the endogenous ribosomal proteins S12 and S5 in Escherichia coli, which are known to be involved in the decoding of the mRNA, on the efficiency of translation of exogenous genes that use non-optimal codons, in vivo. We show that an S12 mutant in E. coli is able to express exogenous genes, with non-optimal codons, to higher levels than the wild-type, and explore the mechanisms underlying this phenomenon in this mutant. Our results suggest that the transient emergence of mutants that allow efficient expression of exogenous genes with non-optimal codons could also increase the chances of fixation of laterally transferred genes.
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Affiliation(s)
- Gidi Pelchovich
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
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15
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Restrictive Streptomycin Resistance Mutations Decrease the Formation of Attaching and Effacing Lesions in Escherichia coli O157:H7 Strains. Antimicrob Agents Chemother 2013; 57:4260-4266. [PMID: 23796920 DOI: 10.1128/aac.00709-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/14/2013] [Indexed: 12/16/2022] Open
Abstract
Streptomycin binds to the bacterial ribosome and disrupts protein synthesis by promoting misreading of mRNA. Restrictive mutations on the ribosomal subunit protein S12 confer a streptomycin resistance (Strr) phenotype and concomitantly increase the accuracy of the decoding process and decrease the rate of translation. Spontaneous Strr mutants of Escherichia coli O157:H7 have been generated for in vivo studies to promote colonization and to provide a selective marker for this pathogen. The locus of enterocyte effacement (LEE) of E. coli O157:H7 encodes a type III secretion system (T3SS), which is required for attaching and effacing to the intestinal epithelium. In this study, we observed decreases in both the expression and secretion levels of the T3SS translocated proteins EspA and EspB in E. coli O157:H7 Strr restrictive mutants, which have K42T or K42I mutations in S12. However, mildly restrictive (K87R) and nonrestrictive (K42R) mutants showed slight or indistinguishable changes in EspA and EspB secretion. Adherence and actin staining assays indicated that restrictive mutations compromised the formation of attaching and effacing lesions in E. coli O157:H7. Therefore, we suggest that E. coli O157:H7 strains selected for Strr should be thoroughly characterized before in vivo and in vitro experiments that assay for LEE-directed phenotypes and that strains carrying nonrestrictive mutations such as K42R make better surrogates of wild-type strains than those carrying restrictive mutations.
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16
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Janssen BD, Hayes CS. The tmRNA ribosome-rescue system. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2012; 86:151-91. [PMID: 22243584 DOI: 10.1016/b978-0-12-386497-0.00005-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The bacterial tmRNA quality control system monitors protein synthesis and recycles stalled translation complexes in a process termed "ribosome rescue." During rescue, tmRNA acts first as a transfer RNA to bind stalled ribosomes, then as a messenger RNA to add the ssrA peptide tag to the C-terminus of the nascent polypeptide chain. The ssrA peptide targets tagged peptides for proteolysis, ensuring rapid degradation of potentially deleterious truncated polypeptides. Ribosome rescue also facilitates turnover of the damaged messages responsible for translational arrest. Thus, tmRNA increases the fidelity of gene expression by promoting the synthesis of full-length proteins. In addition to serving as a global quality control system, tmRNA also plays important roles in bacterial development, pathogenesis, and environmental stress responses. This review focuses on the mechanism of tmRNA-mediated ribosome rescue and the role of tmRNA in bacterial physiology.
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Affiliation(s)
- Brian D Janssen
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA
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17
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Holberger LE, Garza-Sánchez F, Lamoureux J, Low DA, Hayes CS. A novel family of toxin/antitoxin proteins in Bacillus species. FEBS Lett 2011; 586:132-6. [PMID: 22200572 DOI: 10.1016/j.febslet.2011.12.020] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Revised: 12/06/2011] [Accepted: 12/12/2011] [Indexed: 11/25/2022]
Abstract
The C-terminal regions (CT) of Pfam PF04740 proteins share significant sequence identity with the toxic CdiA-CT effector domains of contact-dependent growth inhibition (CDI) systems. In accord with this homology, we find that several PF04740 CT domains inhibit cell growth when expressed in Escherichia coli. This growth inhibition is specifically blocked by antitoxin proteins encoded downstream of each PF04740 gene. The YobL-CT, YxiD-CT and YqcG-CT domains from Bacillus subtilis 168 have cytotoxic RNase activities, which are neutralized by the binding of cognate YobK, YxxD and YqcF antitoxin proteins, respectively. Our results show that PF04740 proteins represent a new family of toxin/antitoxin pairs that are widely distributed in Gram-positive bacteria.
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Affiliation(s)
- Laura E Holberger
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106-9625, USA
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18
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Miller MR, Liu Z, Cazier DJ, Gebhard GM, Herron SR, Zaher HS, Green R, Buskirk AR. The role of SmpB and the ribosomal decoding center in licensing tmRNA entry into stalled ribosomes. RNA (NEW YORK, N.Y.) 2011; 17:1727-1736. [PMID: 21795410 PMCID: PMC3162337 DOI: 10.1261/rna.2821711] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 06/24/2011] [Indexed: 05/31/2023]
Abstract
In bacteria, stalled ribosomes are recycled by a hybrid transfer-messenger RNA (tmRNA). Like tRNA, tmRNA is aminoacylated with alanine and is delivered to the ribosome by EF-Tu, where it reacts with the growing polypeptide chain. tmRNA entry into stalled ribosomes poses a challenge to our understanding of ribosome function because it occurs in the absence of a codon-anticodon interaction. Instead, tmRNA entry is licensed by the binding of its protein partner, SmpB, to the ribosomal decoding center. We analyzed a series of SmpB mutants and found that its C-terminal tail is essential for tmRNA accommodation but not for EF-Tu activation. We obtained evidence that the tail likely functions as a helix on the ribosome to promote accommodation and identified key residues in the tail essential for this step. In addition, our mutational analysis points to a role for the conserved K(131)GKK tail residues in trans-translation after peptidyl transfer to tmRNA, presumably EF-G-mediated translocation or translation of the tmRNA template. Surprisingly, analysis of A1492, A1493, and G530 mutants reveals that while these ribosomal nucleotides are essential for normal tRNA selection, they play little to no role in peptidyl transfer to tmRNA. These studies clarify how SmpB interacts with the ribosomal decoding center to license tmRNA entry into stalled ribosomes.
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Affiliation(s)
- Mickey R. Miller
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Zhu Liu
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - DeAnna J. Cazier
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Grant M. Gebhard
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Steven R. Herron
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
| | - Hani S. Zaher
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Allen R. Buskirk
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA
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19
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Garza-Sánchez F, Schaub RE, Janssen BD, Hayes CS. tmRNA regulates synthesis of the ArfA ribosome rescue factor. Mol Microbiol 2011; 80:1204-19. [PMID: 21435036 DOI: 10.1111/j.1365-2958.2011.07638.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Translation of mRNA lacking an in-frame stop codon leads to ribosome arrest at the 3' end of the transcript. In bacteria, the tmRNA quality control system recycles these stalled ribosomes and tags the incomplete nascent chains for degradation. Although ubiquitous in eubacteria, the ssrA gene encoding tmRNA is not essential for the viability of Escherichia coli and other model bacterial species. ArfA (YhdL) is a mediator of tmRNA-independent ribosome rescue that is essential for the viability of E. coliΔssrA mutants. Here, we demonstrate that ArfA is synthesized from truncated mRNA and therefore regulated by tmRNA tagging activity. RNase III cleaves a hairpin structure within the arfA-coding sequence to produce transcripts that lack stop codons. In the absence of tmRNA tagging, truncated ArfA chains are released from the ribosome. The truncated ArfAΔ18 protein (which lacks 18 C-terminal residues) is functional in ribosome rescue and supports ΔssrA cell viability when expressed from the arfA locus. Other proteobacterial arfA genes also encode hairpins, and transcripts from Dickeya dadantii and Salmonella typhimurium are cleaved by RNase III when expressed in E. coli. Thus, synthesis of ArfA from truncated mRNA appears to be a general mechanism to regulate alternative ribosome rescue activity.
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Affiliation(s)
- Fernando Garza-Sánchez
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, CA 93106-9625, USA
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20
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Diner EJ, Garza-Sánchez F, Hayes CS. Genome engineering using targeted oligonucleotide libraries and functional selection. Methods Mol Biol 2011; 765:71-82. [PMID: 21815087 PMCID: PMC3167224 DOI: 10.1007/978-1-61779-197-0_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The λ phage Red proteins greatly enhance homologous recombination in Escherichia coli. Red-mediated recombination or "recombineering" can be used to construct targeted gene deletions as well as to introduce point mutations into the genome. Here, we describe our method for scanning mutagenesis using recombineered oligonucleotide libraries. This approach entails randomization of specific codons within a target gene, followed by functional selection to isolate mutants. Oligonucleotide library mutagenesis has generated hundreds of novel antibiotic resistance mutations in genes encoding ribosomal proteins, and should be applicable to other systems for which functional selections exist.
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Affiliation(s)
- Elie J Diner
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA, USA
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21
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Schaub RE, Hayes CS. Deletion of the RluD pseudouridine synthase promotes SsrA peptide tagging of ribosomal protein S7. Mol Microbiol 2010; 79:331-41. [PMID: 21219455 DOI: 10.1111/j.1365-2958.2010.07467.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
RluD catalyses formation of three pseudouridine residues within helix 69 of the 50S ribosome subunit. Helix 69 makes important contacts with the decoding centre on the 30S subunit and deletion of rluD was recently shown to interfere with translation termination in Escherichia coli. Here, we show that deletion of rluD increases tmRNA activity on ribosomes undergoing release factor 2 (RF2)-mediated termination at UGA stop codons. Strikingly, tmRNA-mediated SsrA peptide tagging of two proteins, ribosomal protein S7 and LacI, was dramatically increased in ΔrluD cells. S7 tagging was due to a unique C-terminal peptide extension found in E. coli K-12 strains. Introduction of the rpsG gene (encoding S7) from an E. coli B strain abrogated S7 tagging in the ΔrluD background, and partially complemented the mutant's slow-growth phenotype. Additionally, exchange of the K-12 prfB gene (encoding RF2) with the B strain allele greatly reduced tagging in ΔrluD cells. In contrast to E. coli K-12 cells, deletion of rluD in an E. coli B strain resulted in no growth phenotype. These findings indicate that the originally observed rluD phenotypes result from synthetic interactions with rpsG and prfB alleles found within E. coli K-12 strains.
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Affiliation(s)
- Ryan E Schaub
- Department of Molecular, Cellular and Developmental Biology Biomolecular Science and Engineering Program, University of California, Santa Barbara, Santa Barbara, CA 93106-9625, USA
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22
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Barends S, Kraal B, van Wezel GP. The tmRNA-tagging mechanism and the control of gene expression: a review. WILEY INTERDISCIPLINARY REVIEWS-RNA 2010; 2:233-46. [PMID: 21957008 DOI: 10.1002/wrna.48] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The tmRNA-mediated trans-translation system is a unique quality control system in eubacteria that combines translational surveillance with the rescue of stalled ribosomes. During trans-translation, the chimeric tmRNA molecule--which acts as both tRNA and mRNA--is delivered to the ribosomal A site by a ribonucleoprotein complex of SmpB and EF-Tu-GTP, allowing the stalled ribosome to switch template and resume translation on a small coding sequence inside the tmRNA molecule. As a result, the aberrant protein becomes tagged by a sequence that is a target for proteolytic degradation. Thus, the system elegantly combines ribosome recycling with a clean-up function when triggered by truncated transcripts or rare codons. In addition, recent observations point to a specific regulation of the translation of a small number of genes by tmRNA-mediated inhibition or stimulation. In this review, we discuss the most prominent biochemical and structural aspects of trans-translation and then focus on the specific role of tmRNA in stress management and cell-cycle control of morphologically complex bacteria.
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Affiliation(s)
- Sharief Barends
- ProteoNic, Niels Bohrweg 11-13, 2333 CA Leiden, The Netherlands
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