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Lyu Z, Ling Y, van Hoof A, Ling J. Inactivation of the ribosome assembly factor RimP causes streptomycin resistance and impairs motility in Salmonella. Antimicrob Agents Chemother 2024:e0000224. [PMID: 38629858 DOI: 10.1128/aac.00002-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 03/27/2024] [Indexed: 05/02/2024] Open
Abstract
The ribosome is the central hub for protein synthesis and the target of many antibiotics. Although the majority of ribosome-targeting antibiotics inhibit protein synthesis and are bacteriostatic, aminoglycosides promote protein mistranslation and are bactericidal. Understanding the resistance mechanisms of bacteria against aminoglycosides is not only vital for improving the efficacy of this critically important group of antibiotics but also crucial for studying the molecular basis of translational fidelity. In this work, we analyzed Salmonella mutants evolved in the presence of the aminoglycoside streptomycin (Str) and identified a novel gene rimP to be involved in Str resistance. RimP is a ribosome assembly factor critical for the maturation of the 30S small subunit that binds Str. Deficiency in RimP increases resistance against Str and facilitates the development of even higher resistance. Deleting rimP decreases mistranslation and cellular uptake of Str and further impairs flagellar motility. Our work thus highlights a previously unknown mechanism of aminoglycoside resistance via defective ribosome assembly.
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Affiliation(s)
- Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, Maryland, USA
| | - Yunyi Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, Maryland, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, Maryland, USA
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2
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Lyu Z, Ling Y, van Hoof A, Ling J. Deficiency in ribosome biogenesis causes streptomycin resistance and impairs motility in Salmonella. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.08.574728. [PMID: 38260697 PMCID: PMC10802465 DOI: 10.1101/2024.01.08.574728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The ribosome is the central hub for protein synthesis and the target of many antibiotics. Whereas the majority of ribosome-targeting antibiotics inhibit protein synthesis and are bacteriostatic, aminoglycosides promote protein mistranslation and are bactericidal. Understanding the resistance mechanisms of bacteria against aminoglycosides is not only vital for improving the efficacy of this critically important group of antibiotics but also crucial for studying the molecular basis of translational fidelity. In this work, we analyzed Salmonella mutants evolved in the presence of the aminoglycoside streptomycin (Str) and identified a novel gene rimP to be involved in Str resistance. RimP is a ribosome assembly factor critical for the maturation of the 30S small subunit that binds Str. Deficiency in RimP increases resistance against Str and facilitates the development of even higher resistance. Deleting rimP decreases mistranslation and cellular uptake of Str, and further impairs flagellar motility. Our work thus highlights a previously unknown mechanism of aminoglycoside resistance via defective ribosome assembly.
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Affiliation(s)
- Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Yunyi Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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3
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Zhu W, Xi L, Qiao J, Du D, Wang Y, Morigen. Involvement of OxyR and Dps in the repression of replication initiation by DsrA small RNA in Escherichia coli. Gene 2023; 882:147659. [PMID: 37482259 DOI: 10.1016/j.gene.2023.147659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 07/25/2023]
Abstract
Regulation of the cell cycle process is an effective measure to ensure the stability and fidelity of genetic material during the reproduction of bacteria under different stresses. The small RNA DsrA helps bacteria adapt to environments by binding to multiple targets, but its association with the cell cycle remains unclear. Detection by flow cytometry, we first found that the knockout of dsrA promoted replication initiation, and corresponding overexpression of DsrA inhibited replication initiation in Escherichia coli. The absence of the chaperone protein Hfq, the DNA replication negative regulator protein Dps, or the transcription factor OxyR, was found to cause DsrA to no longer inhibit replication initiation. Excess DsrA promotes expression of the oxyR and dps gene, whereas β-galactosidase activity assay showed that deleting oxyR limited the enhancement of dps promoter transcriptional activity by DsrA. OxyR is a known positive regulator of Dps. Our data suggests that the effect of DsrA on replication initiation requires Hfq and that the upregulation of Dps expression by OxyR in response to DsrA levels may be a potential regulatory pathway for the negative regulation of DNA replication initiation.
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Affiliation(s)
- Weiwei Zhu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Lingjun Xi
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Jiaxin Qiao
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Dongdong Du
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Yao Wang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Morigen
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China.
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Sun R, Zhao X, Meng Q, Huang P, Zhao Q, Liu X, Zhang W, Zhang F, Fu Y. Genome-Wide Screening and Characterization of Genes Involved in Response to High Dose of Ciprofloxacin in Escherichia coli. Microb Drug Resist 2022; 28:501-510. [PMID: 35512736 DOI: 10.1089/mdr.2021.0117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The global emergence of antibiotic resistance, especially in Gram-negative bacteria, is an urgent threat to public health. Inevitably, considering its extensive use and misuse, resistance toward ciprofloxacin has increased in almost all clinically relevant bacteria. This study aimed to investigate the transcriptome changes at a high concentration of ciprofloxacin in Escherichia coli. In brief, 1,418 differentially expressed genes (DEGs) were identified, from which 773 genes were upregulated by ciprofloxacin, whereas 651 genes were downregulated. Enriched biological pathways reflected the upregulation of biological processes such as DNA damage and repair system, toxin/antitoxin systems, formaldehyde detoxification system. With kyoto encyclopedia of genes and genomes pathway analysis, higher expressed DEGs were associated with "LPS biosynthesis," "streptomycin biosynthesis," and "polyketide sugar unit biosynthesis." Lower expressed DEGs were associated with "biosynthesis of amino acids" and "flagellar assembly" pathways. After treatment of ciprofloxacin, lipopolysaccharide (LPS) release was increased by two times, and the gene expression level of LPS synthesis was elevated (p < 0.05) in both reference and clinical strains. Our results demonstrated that transient exposure to high-dose ciprofloxacin is a double-edged sword. Cautions should be taken when administering high-dose antibiotic treatment for infectious diseases.
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Affiliation(s)
- Rui Sun
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Xianqi Zhao
- Department of General Surgery, First Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Qingtai Meng
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Ping Huang
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Qian Zhao
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Xinyi Liu
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Wenli Zhang
- Department of Microbiology, Harbin Medical University, Harbin, China
| | - Fengmin Zhang
- Department of Microbiology, Harbin Medical University, Harbin, China
- Wu Lien-Teh Institute, Harbin Medical University, Harbin, China
| | - Yingmei Fu
- Department of Microbiology, Harbin Medical University, Harbin, China
- Wu Lien-Teh Institute, Harbin Medical University, Harbin, China
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Chen J, Qiao Y, Chen G, Chang C, Dong H, Tang B, Cheng X, Liu X, Hua Z. Salmonella flagella confer anti-tumor immunological effect via activating Flagellin/TLR5 signalling within tumor microenvironment. Acta Pharm Sin B 2021; 11:3165-3177. [PMID: 34729307 PMCID: PMC8546927 DOI: 10.1016/j.apsb.2021.04.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 04/02/2021] [Accepted: 04/15/2021] [Indexed: 12/30/2022] Open
Abstract
mediated cancer therapy has achieved remarkable anti-tumor effects in experimental animal models, but the detailed mechanism remains unsolved. In this report, the active involvement of the host immune response in this process was confirmed by comparing the tumor-suppressive effects of Salmonella in immunocompetent and immunodeficient mice bearing melanoma allografts. Since flagella are key inducers of the host immune response during bacterial infection, flagella were genetically disrupted to analyse their involvement in Salmonella-mediated cancer therapy. The results showed that flagellum-deficient strains failed to induce significant anti-tumor effects, even when more bacteria were administered to offset the difference in invasion efficiency. Flagella mainly activate immune cells via Flagellin/Toll-like receptor 5 (TLR5) signalling pathway. Indeed, we showed that exogenous activation of TLR5 signalling by recombinant Flagellin and exogenous expression of TLR5 both enhanced the therapeutic efficacy of flagellum-deficient Salmonella against melanoma. Our study highlighted the therapeutic value of the interaction between Salmonella and the host immune response through Flagellin/TLR5 signalling pathway during Salmonella-mediated cancer therapy, thereby suggesting the potential application of TLR5 agonists in the cancer immune therapy.
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Key Words
- AKT, Akt serine/threonine kinase
- Bacteria-mediated cancer therapy
- CFU, colony-forming units
- CTLA-4, cytotoxic T-lymphocyte-associated protein 4
- Cancer immune therapy
- DN, dominant-negative
- ERBB2, Erb-B2 receptor tyrosine kinase 2
- ERKl, extracellular regulated protein kinase 1
- Flagellin
- Flagellum
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GFP, green fluorescent protein
- IFN-γ, interferon-γ
- IL, interleukins
- IκB, inhibitor of NF-κB
- JNK, c-Jun N-terminal kinase
- LPS, lipopolysaccharide
- LRR, leucine-rich repeat
- MyD88, myeloid differentiation factor 88
- NF-κB
- NF-κB, nuclear factor kappa-B
- PBS, phosphate-buffered saline
- PCR, polymerase chain reaction
- PD-1, programmed cell death protein-1
- PD-L1, programmed cell death-ligand 1
- PEI, polyethylenimine
- Salmonella
- TIR, Toll/Interleukin-1 receptor
- TLR, Toll-like receptor
- TLR5
- TME, tumor microenvironment
- TRAF6, TNF receptor associated factor 6
- VNP20009
- i.p., intraperitoneally
- i.t., intratumorally
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Xie Y, Thompson T, O'Leary C, Crosby S, Nguyen QX, Liu M, Gill JJ. Differential Bacteriophage Efficacy in Controlling Salmonella in Cattle Hide and Soil Models. Front Microbiol 2021; 12:657524. [PMID: 34262535 PMCID: PMC8273493 DOI: 10.3389/fmicb.2021.657524] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 06/04/2021] [Indexed: 01/18/2023] Open
Abstract
Asymptomatic Salmonella carriage in beef cattle is a food safety concern and the beef feedlot environment and cattle hides are reservoirs of this pathogen. Bacteriophages present an attractive non-antibiotic strategy for control of Salmonella in beef. In this study, four diverse and genetically unrelated Salmonella phages, Sergei, Season12, Sw2, and Munch, were characterized and tested alone and in combination for their ability to control Salmonella in cattle hide and soil systems, which are relevant models for Salmonella control in beef production. Phage Sergei is a member of the genus Sashavirus, phage Season12 was identified as a member of the Chivirus genus, Sw2 was identified as a member of the T5-like Epseptimavirus genus, and Munch was found to be a novel “jumbo” myovirus. Observed pathogen reductions in the model systems ranged from 0.50 to 1.75 log10 CFU/cm2 in hides and from 0.53 to 1.38 log10 CFU/g in soil, with phages Sergei and Sw2 producing greater reductions (∼1 log10 CFU/cm2 or CFU/g) than Season12 and Munch. These findings are in accordance with previous observations of phage virulence, suggesting the simple ability of a phage to form plaques on a bacterial strain is not a strong indicator of antimicrobial activity, but performance in liquid culture assays provides a better predictor. The antimicrobial efficacies of phage treatments were found to be phage-specific across model systems, implying that a phage capable of achieving bacterial reduction in one model is more likely to perform well in another. Phage combinations did not produce significantly greater efficacy than single phages even after 24 h in the soil model, and phage-insensitive colonies were not isolated from treated samples, suggesting that the emergence of phage resistance was not a major factor limiting efficacy in this system.
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Affiliation(s)
- Yicheng Xie
- Department of Animal Science, Texas A&M University, College Station, TX, United States.,Center for Phage Technology, Texas A&M University, College Station, TX, United States
| | - Tyler Thompson
- Department of Animal Science, Texas A&M University, College Station, TX, United States
| | - Chandler O'Leary
- Center for Phage Technology, Texas A&M University, College Station, TX, United States.,Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Stephen Crosby
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Quang X Nguyen
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
| | - Mei Liu
- Center for Phage Technology, Texas A&M University, College Station, TX, United States
| | - Jason J Gill
- Department of Animal Science, Texas A&M University, College Station, TX, United States.,Center for Phage Technology, Texas A&M University, College Station, TX, United States
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Masri A, Khan NA, Zoqratt MZHM, Ayub Q, Anwar A, Rao K, Shah MR, Siddiqui R. Transcriptome analysis of Escherichia coli K1 after therapy with hesperidin conjugated with silver nanoparticles. BMC Microbiol 2021; 21:51. [PMID: 33596837 PMCID: PMC7890611 DOI: 10.1186/s12866-021-02097-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 01/26/2021] [Indexed: 12/04/2022] Open
Abstract
Backgrounds Escherichia coli K1 causes neonatal meningitis. Transcriptome studies are indispensable to comprehend the pathology and biology of these bacteria. Recently, we showed that nanoparticles loaded with Hesperidin are potential novel antibacterial agents against E. coli K1. Here, bacteria were treated with and without Hesperidin conjugated with silver nanoparticles, and silver alone, and 50% minimum inhibitory concentration was determined. Differential gene expression analysis using RNA-seq, was performed using Degust software and a set of genes involved in cell stress response and metabolism were selected for the study. Results 50% minimum inhibitory concentration with silver-conjugated Hesperidin was achieved with 0.5 μg/ml of Hesperidin conjugated with silver nanoparticles at 1 h. Differential genetic analysis revealed the expression of 122 genes (≥ 2-log FC, P< 0.01) in both E. coli K1 treated with Hesperidin conjugated silver nanoparticles and E. coli K1 treated with silver alone, compared to untreated E. coli K1. Of note, the expression levels of cation efflux genes (cusA and copA) and translocation of ions, across the membrane genes (rsxB) were found to increase 2.6, 3.1, and 3.3- log FC, respectively. Significant regulation was observed for metabolic genes and several genes involved in the coordination of flagella. Conclusions The antibacterial mechanism of nanoparticles maybe due to disruption of the cell membrane, oxidative stress, and metabolism in E. coli K1. Further studies will lead to a better understanding of the genetic mechanisms underlying treatment with nanoparticles and identification of much needed novel antimicrobial drug candidates. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02097-2.
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Affiliation(s)
- Abdulkader Masri
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, University City, Sharjah, United Arab Emirates.
| | | | - Qasim Ayub
- Monash University Malaysia Genomics Facility, School of Science, 47500, Bandar Sunway, Selangor Darul Ehsan, Malaysia
| | - Ayaz Anwar
- Department of Biological Sciences, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia.
| | - Komal Rao
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Muhammad Raza Shah
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi, 75270, Pakistan
| | - Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
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Dynamic motility selection drives population segregation in a bacterial swarm. Proc Natl Acad Sci U S A 2020; 117:4693-4700. [PMID: 32060120 DOI: 10.1073/pnas.1917789117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Population expansion in space, or range expansion, is widespread in nature and in clinical settings. Space competition among heterogeneous subpopulations during range expansion is essential to population ecology, and it may involve the interplay of multiple factors, primarily growth and motility of individuals. Structured microbial communities provide model systems to study space competition during range expansion. Here we use bacterial swarms to investigate how single-cell motility contributes to space competition among heterogeneous bacterial populations during range expansion. Our results revealed that motility heterogeneity can promote the spatial segregation of subpopulations via a dynamic motility selection process. The dynamic motility selection is enabled by speed-dependent persistence time bias of single-cell motion, which presumably arises from physical interaction between cells in a densely packed swarm. We further showed that the dynamic motility selection may contribute to collective drug tolerance of swarming colonies by segregating subpopulations with transient drug tolerance to the colony edge. Our results illustrate that motility heterogeneity, or "motility fitness," can play a greater role than growth rate fitness in determining the short-term spatial structure of expanding populations.
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Alanyl-tRNA Synthetase Quality Control Prevents Global Dysregulation of the Escherichia coli Proteome. mBio 2019; 10:mBio.02921-19. [PMID: 31848288 PMCID: PMC6918089 DOI: 10.1128/mbio.02921-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mechanisms have evolved to prevent errors in replication, transcription, and translation of genetic material, with translational errors occurring most frequently. Errors in protein synthesis can occur at two steps, during tRNA aminoacylation and ribosome decoding. Recent advances in protein mass spectrometry have indicated that previous reports of translational errors have potentially underestimated the frequency of these events, but also that the majority of translational errors occur during ribosomal decoding, suggesting that aminoacylation errors are evolutionarily less tolerated. Despite that interpretation, there is evidence that some aminoacylation errors may be regulated, and thus provide a benefit to the cell, while others are clearly detrimental. Here, we show that while it has been suggested that regulated Thr-to-Ser substitutions may be beneficial, there is a threshold beyond which these errors are detrimental. In contrast, we show that errors mediated by alanyl-tRNA synthetase (AlaRS) are not well tolerated and induce a global stress response that leads to gross perturbation of the Escherichia coli proteome, with potentially catastrophic effects on fitness and viability. Tolerance for Ala mistranslation appears to be much lower than with other translational errors, consistent with previous reports of multiple proofreading mechanisms targeting mischarged tRNAAla These results demonstrate the essential role of aminoacyl-tRNA proofreading in optimizing cellular fitness and suggest that any potentially beneficial effects of mistranslation may be confined to specific amino acid substitutions.IMPORTANCE Errors in protein synthesis have historically been assumed to be detrimental to the cell. While there are many reports that translational errors are consequential, there is a growing body of evidence that some mistranslation events may be tolerated or even beneficial. Using two models of mistranslation, we compare the direct phenotypic effects of these events in Escherichia coli This work provides insight into the threshold for tolerance of specific mistranslation events that were previously predicted to be broadly neutral to proteome integrity. Furthermore, these data reveal the effects of mistranslation beyond the general unfolded stress response, leading to global translational reprogramming.
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Fan Y, Thompson L, Lyu Z, Cameron TA, De Lay NR, Krachler AM, Ling J. Optimal translational fidelity is critical for Salmonella virulence and host interactions. Nucleic Acids Res 2019; 47:5356-5367. [PMID: 30941426 PMCID: PMC6547416 DOI: 10.1093/nar/gkz229] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/19/2019] [Accepted: 03/24/2019] [Indexed: 01/09/2023] Open
Abstract
Translational fidelity is required for accurate flow of genetic information, but is frequently altered by genetic changes and environmental stresses. To date, little is known about how translational fidelity affects the virulence and host interactions of bacterial pathogens. Here we show that surprisingly, either decreasing or increasing translational fidelity impairs the interactions of the enteric pathogen Salmonella Typhimurium with host cells and its fitness in zebrafish. Host interactions are mediated by Salmonella pathogenicity island 1 (SPI-1). Our RNA sequencing and quantitative RT-PCR results demonstrate that SPI-1 genes are among the most down-regulated when translational fidelity is either increased or decreased. Further, this down-regulation of SPI-1 genes depends on the master regulator HilD, and altering translational fidelity destabilizes HilD protein via enhanced degradation by Lon protease. Our work thus reveals that optimal translational fidelity is pivotal for adaptation of Salmonella to the host environment, and provides important mechanistic insights into this process.
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Affiliation(s)
- Yongqiang Fan
- College of Life and Health Sciences, Northeastern University, Shenyang 110819, People's Republic of China.,Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.,Shenyang National Laboratory for Materials Science, Northeastern University, Shenyang 110819, People's Republic of China
| | - Laurel Thompson
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Zhihui Lyu
- Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
| | - Todd A Cameron
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Nicholas R De Lay
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Anne Marie Krachler
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA
| | - Jiqiang Ling
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030, USA.,Department of Cell Biology and Molecular Genetics, The University of Maryland, College Park, MD 20742, USA
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Biosynthesis of selenium nanoparticles and effects of selenite, selenate, and selenomethionine on cell growth and morphology in Rahnella aquatilis HX2. Appl Microbiol Biotechnol 2018; 102:6191-6205. [PMID: 29806064 DOI: 10.1007/s00253-018-9060-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/23/2018] [Accepted: 04/27/2018] [Indexed: 01/13/2023]
Abstract
Rahnella aquatilis HX2 (proteobacteria) shows tolerance to selenium (Se). The minimum inhibitory concentrations of selenomethionine (Se-Met), selenite [Se (IV)], and selenate [Se (VI)] to HX2 are 4.0, 85.0, and 590.0 mM, respectively. HX2 shows the ability to reduce Se (IV) and Se (VI) to elemental Se nanoparticles (SeNPs). The maximum production of SeNPs by HX2 strain is 1.99 and 3.85 mM in Luria-Bertani (LB) broth with 5 mM Se (IV) and 10 mM Se (VI), respectively. The morphology of SeNPs and cells were observed by transmission electron microscope, environmental scanning electron microscope, and selected area electric diffraction detector. Spherical SeNPs with amorphous structure were found in the cytoplasm, membrane, and exterior of cells. Morphological variations of the cell membrane were further confirmed by the release of cellular materials absorbed at 260 nm. Flagella were inhibited and cell sizes were 1.8-, 1.6-, and 1.2-fold increases with the Se-Met, Se (VI), and Se (IV) treatments, respectively. The real-time quantitative PCR analysis indicated that some of the genes controlling Se metabolism or cell morphology, including cysA, cysP, rodA, ZntA, and ada, were significantly upregulated, while grxA, fliO, flgE, and fliC genes were significantly downregulated in those Se treatments. This study provided novel valuable information concerning the cell morphology along with biological synthesis process of SeNPs in R. aquatilis and demonstrated that the strain HX2 could be applied in both biosynthesis of SeNPs and in management of environmental Se pollution.
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12
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Rewiring protein synthesis: From natural to synthetic amino acids. Biochim Biophys Acta Gen Subj 2017; 1861:3024-3029. [PMID: 28095316 DOI: 10.1016/j.bbagen.2017.01.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/21/2022]
Abstract
BACKGROUND The protein synthesis machinery uses 22 natural amino acids as building blocks that faithfully decode the genetic information. Such fidelity is controlled at multiple steps and can be compromised in nature and in the laboratory to rewire protein synthesis with natural and synthetic amino acids. SCOPE OF REVIEW This review summarizes the major quality control mechanisms during protein synthesis, including aminoacyl-tRNA synthetases, elongation factors, and the ribosome. We will discuss evolution and engineering of such components that allow incorporation of natural and synthetic amino acids at positions that deviate from the standard genetic code. MAJOR CONCLUSIONS The protein synthesis machinery is highly selective, yet not fixed, for the correct amino acids that match the mRNA codons. Ambiguous translation of a codon with multiple amino acids or complete reassignment of a codon with a synthetic amino acid diversifies the proteome. GENERAL SIGNIFICANCE Expanding the genetic code with synthetic amino acids through rewiring protein synthesis has broad applications in synthetic biology and chemical biology. Biochemical, structural, and genetic studies of the translational quality control mechanisms are not only crucial to understand the physiological role of translational fidelity and evolution of the genetic code, but also enable us to better design biological parts to expand the proteomes of synthetic organisms. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.
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