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Sikora F, Budja LVP, Milojevic O, Ziemniewicz A, Dudys P, Görke B. Multiple regulatory inputs including cell envelope stress orchestrate expression of the Escherichia coli rpoN operon. Mol Microbiol 2024; 122:11-28. [PMID: 38770591 DOI: 10.1111/mmi.15280] [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: 12/31/2023] [Revised: 04/21/2024] [Accepted: 05/07/2024] [Indexed: 05/22/2024]
Abstract
The rpoN operon, an important regulatory hub in Enterobacteriaceae, includes rpoN encoding sigma factor σ54, hpf involved in ribosome hibernation, rapZ regulating glucosamine-6-phosphate levels, and two genes encoding proteins of the nitrogen-related phosphotransferase system. Little is known about regulatory mechanisms controlling the abundance of these proteins. This study employs transposon mutagenesis and chemical screens to dissect the complex expression of the rpoN operon. We find that envelope stress conditions trigger read-through transcription into the rpoN operon from a promoter located upstream of the preceding lptA-lptB locus. This promoter is controlled by the envelope stress sigma factor E and response regulator PhoP is required for its full response to a subset of stress signals. σE also stimulates ptsN-rapZ-npr expression using an element downstream of rpoN, presumably by interfering with mRNA processing by RNase E. Additionally, we identify a novel promoter in the 3' end of rpoN that directs transcription of the distal genes in response to ethanol. Finally, we show that translation of hpf and ptsN is individually regulated by the RNA chaperone Hfq, perhaps involving small RNAs. Collectively, our work demonstrates that the rpoN operon is subject to complex regulation, integrating signals related to envelope stress and carbon source quality.
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Affiliation(s)
- Florian Sikora
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna BioCenter (VBC), Vienna, Austria
| | - Lara Veronika Perko Budja
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Olja Milojevic
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Amelia Ziemniewicz
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Przemyslaw Dudys
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Boris Görke
- Max Perutz Labs, Vienna Biocenter Campus (VBC), Vienna, Austria
- Max Perutz Labs, Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
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Sampaio PN, Calado CCR. Enhancing Bioactive Compound Classification through the Synergy of Fourier-Transform Infrared Spectroscopy and Advanced Machine Learning Methods. Antibiotics (Basel) 2024; 13:428. [PMID: 38786156 PMCID: PMC11117366 DOI: 10.3390/antibiotics13050428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/29/2024] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
Bacterial infections and resistance to antibiotic drugs represent the highest challenges to public health. The search for new and promising compounds with anti-bacterial activity is a very urgent matter. To promote the development of platforms enabling the discovery of compounds with anti-bacterial activity, Fourier-Transform Mid-Infrared (FT-MIR) spectroscopy coupled with machine learning algorithms was used to predict the impact of compounds extracted from Cynara cardunculus against Escherichia coli. According to the plant tissues (seeds, dry and fresh leaves, and flowers) and the solvents used (ethanol, methanol, acetone, ethyl acetate, and water), compounds with different compositions concerning the phenol content and antioxidant and antimicrobial activities were obtained. A principal component analysis of the spectra allowed us to discriminate compounds that inhibited E. coli growth according to the conventional assay. The supervised classification models enabled the prediction of the compounds' impact on E. coli growth, showing the following values for accuracy: 94% for partial least squares-discriminant analysis; 89% for support vector machine; 72% for k-nearest neighbors; and 100% for a backpropagation network. According to the results, the integration of FT-MIR spectroscopy with machine learning presents a high potential to promote the discovery of new compounds with antibacterial activity, thereby streamlining the drug exploratory process.
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Affiliation(s)
- Pedro N Sampaio
- COPELABS-Computação e Cognição Centrada nas Pessoas, Faculty of Engineering, Lusófona University, Campo Grande, 376, 1749-024 Lisbon, Portugal
- GREEN-IT-BioResources for Sustainability Unit, Institute of Chemical and Biological Technology António Xavier, ITQB NOVA, Av. da República, 2780-157 Oeiras, Portugal
| | - Cecília C R Calado
- ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Rua Conselheiro Emídio Navarro 1, 1959-007 Lisbon, Portugal
- iBB-Institute for Bioengineering and Biosciences, i4HB-The Associate Laboratory Institute for Health and Bioeconomy, IST-Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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3
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Kassem A, Abbas L, Coutinho O, Opara S, Najaf H, Kasperek D, Pokhrel K, Li X, Tiquia-Arashiro S. Applications of Fourier Transform-Infrared spectroscopy in microbial cell biology and environmental microbiology: advances, challenges, and future perspectives. Front Microbiol 2023; 14:1304081. [PMID: 38075889 PMCID: PMC10703385 DOI: 10.3389/fmicb.2023.1304081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 11/03/2023] [Indexed: 01/02/2024] Open
Abstract
Microorganisms play pivotal roles in shaping ecosystems and biogeochemical cycles. Their intricate interactions involve complex biochemical processes. Fourier Transform-Infrared (FT-IR) spectroscopy is a powerful tool for monitoring these interactions, revealing microorganism composition and responses to the environment. This review explores the diversity of applications of FT-IR spectroscopy within the field of microbiology, highlighting its specific utility in microbial cell biology and environmental microbiology. It emphasizes key applications such as microbial identification, process monitoring, cell wall analysis, biofilm examination, stress response assessment, and environmental interaction investigation, showcasing the crucial role of FT-IR in advancing our understanding of microbial systems. Furthermore, we address challenges including sample complexity, data interpretation nuances, and the need for integration with complementary techniques. Future prospects for FT-IR in environmental microbiology include a wide range of transformative applications and advancements. These include the development of comprehensive and standardized FT-IR libraries for precise microbial identification, the integration of advanced analytical techniques, the adoption of high-throughput and single-cell analysis, real-time environmental monitoring using portable FT-IR systems and the incorporation of FT-IR data into ecological modeling for predictive insights into microbial responses to environmental changes. These innovative avenues promise to significantly advance our understanding of microorganisms and their complex interactions within various ecosystems.
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Affiliation(s)
- Amin Kassem
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Lana Abbas
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Oliver Coutinho
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Somie Opara
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Hawraa Najaf
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Diana Kasperek
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Keshav Pokhrel
- Department of Mathematics and Statistics, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Xiaohua Li
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
| | - Sonia Tiquia-Arashiro
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI, United States
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Fitzgerald DM, Stringer AM, Smith C, Lapierre P, Wade JT. Genome-Wide Mapping of the Escherichia coli PhoB Regulon Reveals Many Transcriptionally Inert, Intragenic Binding Sites. mBio 2023; 14:e0253522. [PMID: 37067422 PMCID: PMC10294691 DOI: 10.1128/mbio.02535-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 03/23/2023] [Indexed: 04/18/2023] Open
Abstract
Genome-scale analyses have revealed many transcription factor binding sites within, rather than upstream of, genes, raising questions as to the function of these binding sites. Here, we use complementary approaches to map the regulon of the Escherichia coli transcription factor PhoB, a response regulator that controls transcription of genes involved in phosphate homeostasis. Strikingly, the majority of PhoB binding sites are located within genes, but these intragenic sites are not associated with detectable transcription regulation and are not evolutionarily conserved. Many intragenic PhoB sites are located in regions bound by H-NS, likely due to shared sequence preferences of PhoB and H-NS. However, these PhoB binding sites are not associated with transcription regulation even in the absence of H-NS. We propose that for many transcription factors, including PhoB, binding sites not associated with promoter sequences are transcriptionally inert and hence are tolerated as genomic "noise." IMPORTANCE Recent studies have revealed large numbers of transcription factor binding sites within the genes of bacteria. The function, if any, of the vast majority of these binding sites has not been investigated. Here, we map the binding of the transcription factor PhoB across the Escherichia coli genome, revealing that the majority of PhoB binding sites are within genes. We show that PhoB binding sites within genes are not associated with regulation of the overlapping genes. Indeed, our data suggest that bacteria tolerate the presence of large numbers of nonregulatory, intragenic binding sites for transcription factors and that these binding sites are not under selective pressure.
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Affiliation(s)
- Devon M. Fitzgerald
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
| | - Anne M. Stringer
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Carol Smith
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Pascal Lapierre
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Joseph T. Wade
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
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5
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Fitzgerald D, Stringer A, Smith C, Lapierre P, Wade JT. Genome-wide mapping of the Escherichia coli PhoB regulon reveals many transcriptionally inert, intragenic binding sites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.07.527549. [PMID: 36798257 PMCID: PMC9934606 DOI: 10.1101/2023.02.07.527549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Genome-scale analyses have revealed many transcription factor binding sites within, rather than upstream of genes, raising questions as to the function of these binding sites. Here, we use complementary approaches to map the regulon of the Escherichia coli transcription factor PhoB, a response regulator that controls transcription of genes involved in phosphate homeostasis. Strikingly, the majority of PhoB binding sites are located within genes, but these intragenic sites are not associated with detectable transcription regulation and are not evolutionarily conserved. Many intragenic PhoB sites are located in regions bound by H-NS, likely due to shared sequence preferences of PhoB and H-NS. However, these PhoB binding sites are not associated with transcription regulation even in the absence of H-NS. We propose that for many transcription factors, including PhoB, binding sites not associated with promoter sequences are transcriptionally inert, and hence are tolerated as genomic "noise". IMPORTANCE Recent studies have revealed large numbers of transcription factor binding sites within the genes of bacteria. The function, if any, of the vast majority of these binding sites has not been investigated. Here, we map the binding of the transcription factor PhoB across the Escherichia coli genome, revealing that the majority of PhoB binding sites are within genes. We show that PhoB binding sites within genes are not associated with regulation of the overlapping genes. Indeed, our data suggest that bacteria tolerate the presence of large numbers of non-regulatory, intragenic binding sites for transcription factors, and that these binding sites are not under selective pressure.
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Affiliation(s)
- Devon Fitzgerald
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
| | - Anne Stringer
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Carol Smith
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Pascal Lapierre
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
| | - Joseph T. Wade
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York, USA
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Dandapani H, Kankaanpää P, Jones PR, Kallio P. A Plasmid-Based Fluorescence Reporter System for Monitoring Oxidative Damage in E. coli. SENSORS (BASEL, SWITZERLAND) 2022; 22:6334. [PMID: 36080791 PMCID: PMC9459809 DOI: 10.3390/s22176334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Quantitating intracellular oxidative damage caused by reactive oxygen species (ROS) is of interest in many fields of biological research. The current systems primarily rely on supplemented oxygen-sensitive substrates that penetrate the target cells, and react with ROS to produce signals that can be monitored with spectroscopic or imaging techniques. The objective here was to design a new non-invasive analytical strategy for measuring ROS-induced damage inside living cells by taking advantage of the native redox sensor system of E. coli. The developed plasmid-based sensor relies on an oxygen-sensitive transcriptional repressor IscR that controls the expression of a fluorescent marker in vivo. The system was shown to quantitatively respond to oxidative stress induced by supplemented H2O2 and lowered cultivation temperatures. Comparative analysis with fluorescence microscopy further demonstrated that the specificity of the reporter system was equivalent to the commercial chemical probe (CellROX). The strategy introduced here is not dependent on chemical probes, but instead uses a fluorescent expression system to detect enzyme-level oxidative damage in microbial cells. This provides a cheap and simple means for analysing enzyme-level oxidative damage in a biological context in E. coli.
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Affiliation(s)
- Hariharan Dandapani
- Molecular Plant Biology, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
| | - Pasi Kankaanpää
- Turku BioImaging and Turku Bioscience Centre, University of Turku, FI-20014 Turku, Finland
- Turku BioImaging and Turku Bioscience Centre, Åbo Akademi University, FI-20500 Turku, Finland
| | - Patrik R. Jones
- Molecular Plant Biology, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2BX, UK
| | - Pauli Kallio
- Molecular Plant Biology, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
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7
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Sampaio PNS, Calado CRC. Antimicrobial evaluation of the Cynara cardunculus extract in Helicobacter pylori cells using mid-infrared spectroscopy and chemometric methods. J Appl Microbiol 2022; 133:1743-1756. [PMID: 35729780 DOI: 10.1111/jam.15679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/17/2022] [Accepted: 06/19/2022] [Indexed: 11/29/2022]
Abstract
AIMS The treatment effectiveness of gastric diseases caused by the bacteria Helicobacter pylori is failing due to high resistance to some antibiotics. Consequently, it is urgent to develop an accurate methodology to screen new antimicrobial agents. METHODS AND RESULTS A preliminary assay, using both therapeutic-based antibiotics (clarithromycin and metronidazole), was conducted to optimize experimental conditions in terms of the sensibility of the Fourier Transform Mid-Infrared spectroscopy (MIR-FTIR) associated with chemometric methods. Principal component analysis was applied to understand how the Cynara extract concentration acts differentially against H. pylori bacteria. The partial least squares model, characterized by R2 = 0.98, and root mean square error cross-validation, 0.011, was developed for the spectral regions (3600 - 2500 cm-1 , and 2000 - 698 cm-1 ). CONCLUSIONS MIR-FTIR spectroscopy associated with chemometric methods can be considered a suitable approach to discover and analyze the promissory antimicrobial agents based on the biomolecular changes observed according to the Cynara extract. SIGNIFICANCE AND IMPACT OF THE STUDY MIR-FTIR spectroscopy and chemometric methods allowed to register the biomolecular changes due to the potential antimicrobial drugs at reduced concentrations comparatively to the conventional assay based on an agar-dilution method, being considered a useful approach to develop a platform to discover new bioactive molecules, allowing to reduce time and costs related to the exploratory step.
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Affiliation(s)
- Pedro N Sousa Sampaio
- DREAMS-Centre for Interdisciplinary Development and Research on Environment, Applied Management and Space, Faculty of Engineering, Lusófona University (ULHT), Lisbon, Portugal
| | - Cecília R C Calado
- CIMOSM - Centro de Investigação em Modelação e Optimização de Sistemas Multifuncionais, Instituto Superior de Engenharia de Lisboa (ISEL), Instituto Politécnico de Lisboa Rua Conselheiro Emídio Navarro, 1, 1959-007, Lisbon, Portugal
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8
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Khaova EA, Kashevarova NM, Tkachenko AG. Ribosome Hibernation: Molecular Strategy of Bacterial Survival (Review). APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822030061] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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9
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Investigation and Rapid Discrimination of Food-Related Bacteria under Stress Treatments Using IR Microspectroscopy. Foods 2021; 10:foods10081850. [PMID: 34441627 PMCID: PMC8392388 DOI: 10.3390/foods10081850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/16/2022] Open
Abstract
Because the robust and rapid determination of spoilage microorganisms is becoming increasingly important in industry, the use of IR microspectroscopy, and the establishment of robust and versatile chemometric models for data processing and classification, is gaining importance. To further improve the chemometric models, bacterial stress responses were induced, to study the effect on the IR spectra and to improve the chemometric model. Thus, in this work, nine important food-relevant microorganisms were subjected to eight stress conditions, besides the regular culturing as a reference. Spectral changes compared to normal growth conditions without stressors were found in the spectral regions of 900-1500 cm-1 and 1500-1700 cm-1. These differences might stem from changes in the protein secondary structure, exopolymer production, and concentration of nucleic acids, lipids, and polysaccharides. As a result, a model for the discrimination of the studied microorganisms at the genus, species and strain level was established, with an accuracy of 96.6%. This was achieved despite the inclusion of various stress conditions and times after incubation of the bacteria. In addition, a model was developed for each individual microorganism, to separate each stress condition or regular treatment with 100% accuracy.
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da Cunha BR, Zoio P, Fonseca LP, Calado CRC. Technologies for High-Throughput Identification of Antibiotic Mechanism of Action. Antibiotics (Basel) 2021; 10:565. [PMID: 34065815 PMCID: PMC8151116 DOI: 10.3390/antibiotics10050565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 05/05/2021] [Accepted: 05/10/2021] [Indexed: 01/23/2023] Open
Abstract
There are two main strategies for antibiotic discovery: target-based and phenotypic screening. The latter has been much more successful in delivering first-in-class antibiotics, despite the major bottleneck of delayed Mechanism-of-Action (MOA) identification. Although finding new antimicrobial compounds is a very challenging task, identifying their MOA has proven equally challenging. MOA identification is important because it is a great facilitator of lead optimization and improves the chances of commercialization. Moreover, the ability to rapidly detect MOA could enable a shift from an activity-based discovery paradigm towards a mechanism-based approach. This would allow to probe the grey chemical matter, an underexplored source of structural novelty. In this study we review techniques with throughput suitable to screen large libraries and sufficient sensitivity to distinguish MOA. In particular, the techniques used in chemical genetics (e.g., based on overexpression and knockout/knockdown collections), promoter-reporter libraries, transcriptomics (e.g., using microarrays and RNA sequencing), proteomics (e.g., either gel-based or gel-free techniques), metabolomics (e.g., resourcing to nuclear magnetic resonance or mass spectrometry techniques), bacterial cytological profiling, and vibrational spectroscopy (e.g., Fourier-transform infrared or Raman scattering spectroscopy) were discussed. Ultimately, new and reinvigorated phenotypic assays bring renewed hope in the discovery of a new generation of antibiotics.
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Affiliation(s)
- Bernardo Ribeiro da Cunha
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa (UL), Av. Rovisco Pais, 1049-001 Lisboa, Portugal; (B.R.d.C.); (P.Z.); (L.P.F.)
| | - Paulo Zoio
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa (UL), Av. Rovisco Pais, 1049-001 Lisboa, Portugal; (B.R.d.C.); (P.Z.); (L.P.F.)
- CIMOSM—Centro de Investigação em Modelação e Optimização de Sistemas Multifuncionais, ISEL—Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro 1, 1959-007 Lisboa, Portugal
| | - Luís P. Fonseca
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa (UL), Av. Rovisco Pais, 1049-001 Lisboa, Portugal; (B.R.d.C.); (P.Z.); (L.P.F.)
| | - Cecília R. C. Calado
- CIMOSM—Centro de Investigação em Modelação e Optimização de Sistemas Multifuncionais, ISEL—Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro 1, 1959-007 Lisboa, Portugal
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11
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Enhanced glycolic acid yield through xylose and cellobiose utilization by metabolically engineered Escherichia coli. Bioprocess Biosyst Eng 2021; 44:1081-1091. [PMID: 33527231 DOI: 10.1007/s00449-020-02502-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 12/24/2020] [Indexed: 12/11/2022]
Abstract
Microbial biorefinery is a promising route toward sustainable production of glycolic acid (GA), a valuable raw material for various industries. However, inherent microbial GA production has limited substrate consumption using either D-xylose or D-glucose as carbon catabolite repression (CCR) averts their co-utilization. To bypass CCR, a GA-producing strain using D-xylose via Dahms pathway was engineered to allow cellobiose uptake. Unlike glucose, cellobiose was assimilated and intracellularly degraded without repressing D-xylose uptake. The final GA-producing E. coli strain (CLGA8) has an overexpressed cellobiose phosphorylase (cep94A) from Saccharophagus degradans 2-40 and an activated glyoxylate shunt pathway. Expression of cep94A improved GA production reaching the maximum theoretical yield (0.51 g GA g-1 xylose), whereas activation of glyoxylate shunt pathway enabled GA production from cellobiose, which further increased the GA titer (2.25 g GA L-1). To date, this is the highest reported GA yield from D-xylose through Dahms pathway in an engineered E. coli with cellobiose as co-substrate.
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12
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Ribeiro da Cunha B, Fonseca LP, Calado CRC. Simultaneous elucidation of antibiotic mechanism of action and potency with high-throughput Fourier-transform infrared (FTIR) spectroscopy and machine learning. Appl Microbiol Biotechnol 2021; 105:1269-1286. [PMID: 33443637 DOI: 10.1007/s00253-021-11102-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/09/2020] [Accepted: 01/05/2021] [Indexed: 12/15/2022]
Abstract
The low rate of discovery and rapid spread of resistant pathogens have made antibiotic discovery a worldwide priority. In cell-based screening, the mechanism of action (MOA) is identified after antimicrobial activity. This increases rediscovery, impairs low potency candidate detection, and does not guide lead optimization. In this study, high-throughput Fourier-transform infrared (FTIR) spectroscopy was used to discriminate the MOA of 14 antibiotics at pathway, class, and individual antibiotic level. For that, the optimal combinations and parametrizations of spectral preprocessing were selected with cross-validated partial least squares discriminant analysis, to which various machine learning algorithms were applied. This coherently resulted in very good accuracies, independently of the algorithms, and at all levels of MOA. Particularly, an ensemble of subspace discriminants predicted the known pathway (98.6%), antibiotic classes (100%), and individual antibiotics (97.8%) with exceptional accuracy, and similar results were obtained for simulated novel MOA. Even at very low concentrations (1 μg/mL) and growth inhibition (15%), over 70% pathway and class accuracy was achieved, suggesting FTIR spectroscopy can probe the grey chemical matter. Prediction of inhibitory effect was also examined, for which a squared exponential Gaussian process regression yielded a root mean square error of 0.33 and a R2 of 0.92, indicating that metabolic alterations leading to growth inhibition are intrinsically reflected on FTIR spectra beyond cell density. KEY POINTS: • Antibiotic MOA and potency estimated with high-throughput FTIR spectroscopy • Sub-inhibitory MOA identification suggests ability to explore grey chemical matter • Data analysis optimization improved MOA identification at antibiotic level by 38.
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Affiliation(s)
- Bernardo Ribeiro da Cunha
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa (UL), Av. Rovisco Pais, 1049-001, Lisbon, Portugal. .,Departamento de Engenharia Química, ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa (IPL), R. Conselheiro Emídio Navarro 1, 1959-007, Lisbon, Portugal.
| | - Luís P Fonseca
- Institute for Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa (UL), Av. Rovisco Pais, 1049-001, Lisbon, Portugal
| | - Cecília R C Calado
- Departamento de Engenharia Química, ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa (IPL), R. Conselheiro Emídio Navarro 1, 1959-007, Lisbon, Portugal
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13
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Sampaio PS, Calado CRC. Potential of FTIR-Spectroscopy for Drugs Screening against Helicobacter pylori. Antibiotics (Basel) 2020; 9:antibiotics9120897. [PMID: 33322665 PMCID: PMC7763841 DOI: 10.3390/antibiotics9120897] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 12/16/2022] Open
Abstract
Helicobacter pylori colonizes the human stomach of half of the world's population. The infection if not treated, persists through life, leading to chronic gastric inflammation, that may progress to severe diseases as peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. The first line of treatment, based on 7 to 21 days of two antibiotics associated with a proton pump inhibitor, is, however, already failing most due to patient non-compliance that leads to antibiotic resistance. It is, therefore, urgent to screen for new and more efficient antimicrobials against this bacterium. In this work, Fourier Transform Infrared (FTIR) spectroscopy was evaluated to screen new drugs against H. pylori, in rapid (between 1 to 6 h), and high-throughput mode and based on a microliter volume processes in relation to the agar dilution method. The reference H. pylori strains 26,695 and J99, were evaluated against a peptide-based antimicrobial and the clinical antibiotic clarithromycin, respectively. After optimization of the assay conditions, as the composition of the incubation mixture, the time of incubation, and spectral pre-processing, it was possible to reproducibly observe the effect of the drug on the bacterial molecular fingerprint as pointed by the spectra principal component analysis. The spectra, obtained from both reference strains, after its incubation with drugs concentrations lower than the MIC, presented peak ratios statistically different (p < 0.05) in relation to the bacteria incubated with drugs concentrations equal or higher to the MIC. It was possible to develop a partial least square regression model, enabling to predict from spectra of both bacteria strains, the drug concentration on the assay, with a high correlation coefficient between predicted and experimental data (0.91) and root square error of 40% of the minimum inhibitory concentration. All this points to the high potential of the technique for drug screening against this fastidious growth bacterium.
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Affiliation(s)
- Pedro Sousa Sampaio
- DREAMS—Interdisciplinary Center for Development and Research in Environment, Applied Management and Space, Faculty of Engineering, Lusophone University of Humanities and Technologies, Campo Grande, 376, 1749‑024 Lisbon, Portugal;
- CIMOSM—Centro de Investigação em Modelação e Optimização de Sistemas Multifuncionais, ISEL—Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro 1, 1959-007 Lisboa, Portugal
| | - Cecília R. C. Calado
- CIMOSM—Centro de Investigação em Modelação e Optimização de Sistemas Multifuncionais, ISEL—Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, R. Conselheiro Emídio Navarro 1, 1959-007 Lisboa, Portugal
- Correspondence:
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14
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Ribeiro da Cunha B, Fonseca LP, Calado CRC. A phenotypic screening bioassay for Escherichia coli stress and antibiotic responses based on Fourier-transform infrared (FTIR) spectroscopy and multivariate analysis. J Appl Microbiol 2019; 127:1776-1789. [PMID: 31464358 DOI: 10.1111/jam.14429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 08/21/2019] [Accepted: 08/21/2019] [Indexed: 12/22/2022]
Abstract
AIMS To develop and optimize a Fourier-transform infrared spectroscopy (FTIRS) phenotypic screening bioassay for stress responses, regarding the effect of nutrient content, bacterial growth phase and stress agent exposure time. METHODS AND RESULTS A high-throughput FTIRS bioassay was developed to distinguish the stress responses of Escherichia coli to sodium hydroxide, hydrochloric acid, sodium chloride, sodium hypochlorite and ethanol. Principal component analysis and hierarchical clustering were used to quantify the effect of each parameter on bioassay performance, namely its reproducibility and metabolic resolution. Bioassay performance varied greatly, ranging from poor to very good. Spectra were partitioned into biologically relevant regions to evaluate their contributions to bioassay performance, but further improvements were not observed. Bioassay optimization was validated against empirical parameters, which confirmed a closer representation of known mechanisms on the antibiotic-induced stress responses. CONCLUSIONS The optimized bioassay used standard nutrient content, cells in the late-stationary growth phase and a one-shift exposure duration. Only the optimized bioassay adequately and reproducibly distinguished the E. coli stress and antibiotic responses. The absence of performance improvements using partitioned spectra indicated that stress responses are imprinted on the whole-spectra metabolic signature. SIGNIFICANCE AND IMPACT OF THE STUDY Highly optimized FTIRS bioassay parameters are vital in capturing whole-spectra metabolic signatures that can be used for satisfactory and reproducible phenotypic screening of stress and antibiotic responses.
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Affiliation(s)
- B Ribeiro da Cunha
- iBB - Institute of Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa, Lisboa, Portugal.,ISEL - Instituto Superior de Engenharia de Lisboa (ISEL), Instituto Politécnico de Lisboa (IPL), Lisboa, Portugal
| | - L P Fonseca
- iBB - Institute of Bioengineering and Biosciences (iBB), Instituto Superior Técnico (IST), Universidade de Lisboa, Lisboa, Portugal
| | - C R C Calado
- ISEL - Instituto Superior de Engenharia de Lisboa (ISEL), Instituto Politécnico de Lisboa (IPL), Lisboa, Portugal
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15
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Ligowska-Marzęta M, Hancock V, Ingmer H, M Aarestrup F. Comparison of Gene Expression Profiles of Uropathogenic Escherichia Coli CFT073 after Prolonged Exposure to Subinhibitory Concentrations of Different Biocides. Antibiotics (Basel) 2019; 8:antibiotics8040167. [PMID: 31569631 PMCID: PMC6963283 DOI: 10.3390/antibiotics8040167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 09/19/2019] [Accepted: 09/23/2019] [Indexed: 01/24/2023] Open
Abstract
Biocides are chemical compounds widely used for sterilization and disinfection. The aim of this study was to examine whether exposure to subinhibitory biocide concentrations influenced transcriptional expression of genes that could improve a pathogen’s drug resistance or fitness. We used DNA microarrays to investigate the transcriptome of the uropathogenic Escherichia coli strain CFT073 in response to prolonged exposure to subinhibitory concentrations of four biocides: benzalkonium chloride, chlorhexidine, hydrogen peroxide and triclosan. Transcription of a gene involved in polymyxin resistance, arnT, was increased after treatment with benzalkonium chloride. However, pretreatment of the bacteria with this biocide did not result in cross-resistance to polymyxin in vitro. Genes encoding products related to transport formed the functional group that was most affected by biocides, as 110 out of 884 genes in this category displayed altered transcription. Transcripts of genes involved in cysteine uptake, sulfate assimilation, dipeptide transport, as well as cryptic phage genes were also more abundant in response to several biocides. Additionally, we identified groups of genes with transcription changes unique to single biocides that might include potential targets for the biocides. The biocides did not increase the resistance potential of the pathogen to other antimicrobials.
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Affiliation(s)
- Małgorzata Ligowska-Marzęta
- Department of Bacteria, Parasites and Fungi, Statens Serum Institut, 2300 Copenhagen, Denmark.
- Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
| | - Viktoria Hancock
- Renal Research & Innovation, Baxter International Inc., SE-220 10 Lund, Sweden.
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, 1870 Frederiksberg, Denmark.
| | - Frank M Aarestrup
- Research Group for Genomic Epidemiology, National Food Institute, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
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16
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Abstract
Protein synthesis consumes a large fraction of available resources in the cell. When bacteria encounter unfavorable conditions and cease to grow, specialized mechanisms are in place to ensure the overall reduction of costly protein synthesis while maintaining a basal level of translation. A number of ribosome-associated factors are involved in this regulation; some confer an inactive, hibernating state of the ribosome in the form of 70S monomers (RaiA; this and the following are based on Escherichia coli nomenclature) or 100S dimers (RMF and HPF homologs), and others inhibit translation at different stages in the translation cycle (RsfS, YqjD and paralogs, SRA, and EttA). Stationary phase cells therefore exhibit a complex array of different ribosome subpopulations that adjusts the translational capacity of the cell to the encountered conditions and ensures efficient reactivation of translation when conditions improve. Here, we review the current state of research regarding stationary phase-specific translation factors, in particular ribosome hibernation factors and other forms of translational regulation in response to stress conditions.
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Affiliation(s)
- Thomas Prossliner
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark;
| | | | | | - Kenn Gerdes
- Department of Biology, University of Copenhagen, DK-2200 Copenhagen, Denmark;
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17
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Naseri T, Bahaloo-Horeh N, Mousavi SM. Environmentally friendly recovery of valuable metals from spent coin cells through two-step bioleaching using Acidithiobacillus thiooxidans. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2019; 235:357-367. [PMID: 30708273 DOI: 10.1016/j.jenvman.2019.01.086] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 01/21/2019] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
The technology for recycling the spent coin cells is pressing needed due to a large amount of generated spent coin cells. However, there is little information about the recycling technology of spent coin cells. In this work, a two-step bioleaching method for recovery of metals from spent coin cells by Acidithiobacillus thiooxidans is performed for the first time. In this regard, the growth characteristics of A. thiooxidans was investigated in pure culture and during the two-step bioleaching approach. The highest recovery of Li, Co and Mn was achieved at a pulp density of 30 g L-1, in values of 99%, 60%, and 20%, respectively. The structural analyzes confirmed the progress of bioleaching process. In addition, the kinetics models showed that the chemical reaction was the rate-controlling step of the two-step bioleaching of spent coin cells. The comparative results between bioleaching and chemical leaching showed that Acidithiobacillus thiooxidans can enhance the leaching of metals. Toxicity characteristic leaching procedure of the spent coin cells powder demonstrated that the bioleached residue met the environmental limitations for safe disposal. In fact, bioleaching is an effective and promising route to reduce the environmental hazard of spent coin cells.
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Affiliation(s)
- Tannaz Naseri
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
| | - Nazanin Bahaloo-Horeh
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
| | - Seyyed Mohammad Mousavi
- Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, Tehran, Iran.
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18
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King T, Kocharunchitt C, Gobius K, Bowman JP, Ross T. Physiological Response of Escherichia coli O157:H7 Sakai to Dynamic Changes in Temperature and Water Activity as Experienced during Carcass Chilling. Mol Cell Proteomics 2016; 15:3331-3347. [PMID: 27615263 PMCID: PMC5098033 DOI: 10.1074/mcp.m116.063065] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 09/04/2016] [Indexed: 02/03/2023] Open
Abstract
Enterohemeorrhagic Escherichia coli is a leading cause of foodborne illness, with the majority of cases linked to foods of bovine origin. Currently, no completely effective method for controlling this pathogen during carcass processing exists. Understanding how this pathogen behaves under those stress conditions experienced on the carcass during chilling in cold air could offer opportunities for development or improvement of effective decontamination processes. Therefore, we studied the growth kinetics and physiological response of exponential phase E. coli O157:H7 Sakai cultures upon an abrupt downshift in temperature and water activity (from 35 °C aw 0.993 to 14 °C aw 0.967). A parallel Biolog study was conducted to follow the phenotypic responses to 190 carbon sources. Exposure of E. coli to combined cold and water activity stresses resulted in a complex pattern of population changes. This pattern could be divided into two main phases, including adaptation and regrowth phases, based on growth kinetics and clustering analyses. The transcriptomic and proteomic studies revealed that E. coli exhibited a "window" of cell susceptibility (i.e. weaknesses) during adaptation phase. This included apparent DNA damage, the downregulation of molecular chaperones and proteins associated with responses to oxidative damage. However, E. coli also displayed a transient induction in the RpoE-controlled envelope stress response and activation of the master stress regulator RpoS and the Rcs phosphorelay system involved in colanic acid biosynthesis. Increased expression was observed for several genes and/or proteins involved in DNA repair, protein and peptide degradation, amino acid biosynthesis, and carbohydrate catabolism and energy generation. Furthermore, the Biolog study revealed reduced carbon source utilization during adaptation phase, indicating the disruption of energy-generating processes. This study provides insight into the physiological response of E. coli during exposure to combined cold and water activity stress, which could be exploited to enhance the microbiological safety of carcasses and related foods.
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Affiliation(s)
- Thea King
- From the ‡CSIRO Agriculture and Food, North Ryde, NSW 2113, Australia;
| | - Chawalit Kocharunchitt
- §Food Safety Centre, Tasmanian Institute of Agriculture, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart TAS 7001, Australia
| | - Kari Gobius
- ¶CSIRO Agriculture and Food, Werribee, VIC 3030, Australia
| | - John P Bowman
- §Food Safety Centre, Tasmanian Institute of Agriculture, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart TAS 7001, Australia
| | - Tom Ross
- §Food Safety Centre, Tasmanian Institute of Agriculture, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart TAS 7001, Australia
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19
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Youngquist JT, Korosh TC, Pfleger BF. Functional genomics analysis of free fatty acid production under continuous phosphate limiting conditions. J Ind Microbiol Biotechnol 2016; 44:759-772. [PMID: 27738839 DOI: 10.1007/s10295-016-1846-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/28/2016] [Indexed: 12/19/2022]
Abstract
Free fatty acids (FFA) are an attractive platform chemical that serves as a functional intermediate in metabolic pathways for producing oleochemicals. Many groups have established strains of Escherichia coli capable of producing various chain-length mixtures of FFA by heterologous expression of acyl-ACP thioesterases. For example, high levels of dodecanoic acid are produced by an E. coli strain expressing the Umbellularia californica FatB2 thioesterase, BTE. Prior studies achieved high dodecanoic acid yields and productivities under phosphate-limiting media conditions. In an effort to understand the metabolic and physiological changes that led to increased FFA production, the transcriptome of this strain was assessed as a function of nutrient limitation and growth rate. FFA generation under phosphate limitation led to consistent changes in transporter expression, osmoregulation, and central metabolism. Guided by these results, targeted knockouts led to a further ~11 % in yield in FFA.
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Affiliation(s)
- J Tyler Youngquist
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI, USA
| | - Travis C Korosh
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI, USA.,Graduate Program in Environmental Chemistry and Technology, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, 3629 Engineering Hall, 1415 Engineering Drive, Madison, WI, USA. .,Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA.
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20
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Faghihzadeh F, Anaya NM, Schifman LA, Oyanedel-Craver V. Fourier transform infrared spectroscopy to assess molecular-level changes in microorganisms exposed to nanoparticles. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s41204-016-0001-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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21
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Chevalier C, Le Goffic R, Jamme F, Leymarie O, Réfrégiers M, Delmas B. Synchrotron Infrared and Deep UV Fluorescent Microspectroscopy Study of PB1-F2 β-Aggregated Structures in Influenza A Virus-infected Cells. J Biol Chem 2016; 291:9060-72. [PMID: 26896002 DOI: 10.1074/jbc.m115.710533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Indexed: 11/06/2022] Open
Abstract
PB1-F2 is a virulence factor of influenza A virus (IAV) whose functions remain misunderstood. The different roles of PB1-F2 may be linked to its structural polymorphism and to its propensity to assemble into oligomers and amyloid fibers in the vicinity of the membrane of IAV-infected cells. Here, we monitored the impact of PB1-F2 on the biochemical composition and protein structures of human epithelial pulmonary cells (A549) and monocytic cells (U937) upon IAV infection using synchrotron Fourier-transform infrared (FTIR) and deep UV (DUV) microscopies at the single-cell level. Cells were infected with a wild-type IAV and its PB1-F2 knock-out mutant for analyses at different times post-infection. IR spectra were recorded in each condition and processed to evaluate the change in the component band of the spectra corresponding to the amide I (secondary structure) and the CH stretching region (membrane). The IR spectra analysis revealed that expression of PB1-F2 in U937 cells, but not in A549 cells, results in the presence of a specific β-aggregate signature. Furthermore, the lipid membrane composition of U937 cells expressing PB1-F2 was also altered in a cell type-dependent manner. Using DUV microscopy and taking advantage of the high content of tryptophan residues in the sequence of PB1-F2 (5/90 aa), we showed that the increase of the autofluorescent signal recorded in monocytic cells could be correlated with the IR detection of β-aggregates. Altogether, our results constitute an important step forward in the understanding of the cell type-dependent function of PB1-F2.
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Affiliation(s)
| | - Ronan Le Goffic
- From the VIM, UR892, INRA, Université PARIS-SACLAY, 78350 Jouy-en-Josas and
| | - Frédéric Jamme
- the DISCO and SMIS Beamlines, Synchrotron SOLEIL, L'Orme des Merisiers, 91190 Saint-Aubin, Gif-sur Yvette, France
| | - Olivier Leymarie
- From the VIM, UR892, INRA, Université PARIS-SACLAY, 78350 Jouy-en-Josas and
| | - Matthieu Réfrégiers
- the DISCO and SMIS Beamlines, Synchrotron SOLEIL, L'Orme des Merisiers, 91190 Saint-Aubin, Gif-sur Yvette, France
| | - Bernard Delmas
- From the VIM, UR892, INRA, Université PARIS-SACLAY, 78350 Jouy-en-Josas and
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22
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Saulou-Bérion C, Gonzalez I, Enjalbert B, Audinot JN, Fourquaux I, Jamme F, Cocaign-Bousquet M, Mercier-Bonin M, Girbal L. Escherichia coli under Ionic Silver Stress: An Integrative Approach to Explore Transcriptional, Physiological and Biochemical Responses. PLoS One 2015; 10:e0145748. [PMID: 26696268 PMCID: PMC4699211 DOI: 10.1371/journal.pone.0145748] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 12/08/2015] [Indexed: 11/19/2022] Open
Abstract
For a better understanding of the systemic effect of sub-lethal micromolar concentrations of ionic silver on Escherichia coli, we performed a multi-level characterization of cells under Ag+-mediated stress using an integrative biology approach combining physiological, biochemical and transcriptomic data. Physiological parameters, namely bacterial growth and survival after Ag+ exposure, were first quantified and related to the accumulation of intracellular silver, probed for the first time by nano secondary ion mass spectroscopy at sub-micrometer lateral resolution. Modifications in E. coli biochemical composition were evaluated under Ag+-mediated stress by in situ synchrotron Fourier-transform infrared microspectroscopy and a comprehensive transcriptome response was also determined. Using multivariate statistics, correlations between the physiological parameters, the extracellular concentration of AgNO3 and the intracellular silver content, gene expression profiles and micro-spectroscopic data were investigated. We identified Ag+-dependent regulation of gene expression required for growth (e.g. transporter genes, transcriptional regulators, ribosomal proteins), for ionic silver transport and detoxification (e.g. copA, cueO, mgtA, nhaR) and for coping with various types of stress (dnaK, pspA, metA,R, oxidoreductase genes). The silver-induced shortening of the acyl chain of fatty acids, mostly encountered in cell membrane, was highlighted by microspectroscopy and correlated with the down-regulated expression of genes involved in fatty acid transport (fadL) and synthesis/modification of lipid A (lpxA and arnA). The increase in the disordered secondary structure of proteins in the presence of Ag+ was assessed through the conformational shift shown for amides I and II, and further correlated with the up-regulated expression of peptidase (hfq) and chaperone (dnaJ), and regulation of transpeptidase expression (ycfS and ycbB). Interestingly, as these transpeptidases act on the structural integrity of the cell wall, regulation of their expression may explain the morphological damage reported under Ag+-mediated stress. This result clearly demonstrates that the cell membrane is a key target of ionic silver.
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Affiliation(s)
- Claire Saulou-Bérion
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
- CNRS, UMR5504, Toulouse, France
| | - Ignacio Gonzalez
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
- CNRS, UMR5504, Toulouse, France
| | - Brice Enjalbert
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
- CNRS, UMR5504, Toulouse, France
| | - Jean-Nicolas Audinot
- Luxembourg Institute of Science and Technology (LIST), Material Research & Technology Department (MRT), Belvaux, Luxembourg
| | - Isabelle Fourquaux
- Faculté de Médecine Rangueil, Centre de Microscopie Electronique Appliquée à la Biologie (CMEAB), Toulouse Cedex, France
| | - Frédéric Jamme
- INRA, UAR1008, CEPIA, Nantes, France
- Synchrotron SOLEIL, Gif-sur-Yvette, France
| | - Muriel Cocaign-Bousquet
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
- CNRS, UMR5504, Toulouse, France
| | - Muriel Mercier-Bonin
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
- CNRS, UMR5504, Toulouse, France
| | - Laurence Girbal
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, Toulouse, France
- CNRS, UMR5504, Toulouse, France
- * E-mail:
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23
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Boyarskiy S, Davis López S, Kong N, Tullman-Ercek D. Transcriptional feedback regulation of efflux protein expression for increased tolerance to and production of n-butanol. Metab Eng 2015; 33:130-137. [PMID: 26656942 DOI: 10.1016/j.ymben.2015.11.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/28/2015] [Accepted: 11/23/2015] [Indexed: 01/11/2023]
Abstract
Microorganisms can be engineered to produce a variety of biofuels and commodity chemicals. The accumulation of these products, however, is often toxic to the cells and subsequently lowers production yields. Efflux pumps are a natural mechanism for alleviating toxicity through secretion of the product; unfortunately, pump overexpression also often inhibits growth. Tuning expression levels with inducible promoters is time-consuming and the reliance on small-molecule inducers is cost-prohibitive in industry. We design an expression regulation system utilizing a native Escherichia coli stress promoter, PgntK, to provide negative feedback to regulate transporter expression levels. We test the promoter in the context of the efflux pump AcrB and its butanol-secreting variant, AcrBv2. PgntK-driven AcrBv2 confers increased tolerance to n-butanol and increased titers of n-butanol in production. Furthermore, the system is responsive to stress from toxic overexpression of other membrane-associated proteins. Our results suggest a use for feedback regulation networks in membrane protein expression.
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Affiliation(s)
- Sergey Boyarskiy
- Joint Graduate Group in Bioengineering at UC Berkeley and UCSF, 306 Stanley Hall, Berkeley, CA 94720, United States
| | - Stephanie Davis López
- Department of Chemistry, University of California Berkeley, 201 Gilman Hall, Berkeley, CA 94720, United States
| | - Niwen Kong
- Department of Molecular and Cell Biology, University of California Berkeley, 142 LSA #3200, Berkeley, CA 94720, United States
| | - Danielle Tullman-Ercek
- Joint Graduate Group in Bioengineering at UC Berkeley and UCSF, 306 Stanley Hall, Berkeley, CA 94720, United States; Department of Chemistry, University of California Berkeley, 201 Gilman Hall, Berkeley, CA 94720, United States; Department of Chemical and Biomolecular Engineering, University of California Berkeley, 201 Gilman Hall, Berkeley, CA 94720, United States.
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24
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Tolerance of Salmonella enterica serovar Typhimurium to nisin combined with EDTA is accompanied by changes in cellular composition. Food Res Int 2015. [DOI: 10.1016/j.foodres.2014.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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25
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Yoshida H, Wada A. The 100S ribosome: ribosomal hibernation induced by stress. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:723-32. [PMID: 24944100 DOI: 10.1002/wrna.1242] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 04/18/2014] [Accepted: 04/18/2014] [Indexed: 01/01/2023]
Abstract
One of the most important cellular events in all organisms is protein synthesis (translation), which is catalyzed by ribosomes. The regulation of translational activity is dependent on the environmental situation of the cell. A decrease in overall translation under stress conditions is mainly accompanied by the formation of functionally inactive 100S ribosomes in bacteria. The 100S ribosome is a dimer of two 70S ribosomes that is formed through interactions between their 30S subunits. Two mechanisms of 100S ribosome formation are known: one involving ribosome modulation factor (RMF) and short hibernation promoting factor (HPF) in a part of Gammaproteobacteria including Escherichia coli, and the other involving only long HPF in the majority of bacteria. The expression of RMF is regulated by ppGpp and cyclic AMP-cAMP receptor protein (cAMP-CRP) induced by amino acid starvation and glucose depletion, respectively. When stress conditions are removed, the 100S ribosome immediately dissociates into the active 70S ribosomes by releasing RMF. The stage in the ribosome cycle at which the ribosome loses translational activity is referred to as 'Hibernation'. The lifetime of cells that cannot form 100S ribosomes by deletion of the rmf gene is shorter than that of parental cells under stress conditions in E. coli. This fact indicates that the interconversion system between active 70S ribosomes and inactive 100S ribosomes is an important survival strategy for bacteria.
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Affiliation(s)
- Hideji Yoshida
- Department of Physics, Osaka Medical College, Osaka, Japan
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26
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King T, Kocharunchitt C, Gobius K, Bowman JP, Ross T. Global genome response of Escherichia coli O157∶H7 Sakai during dynamic changes in growth kinetics induced by an abrupt temperature downshift. PLoS One 2014; 9:e99627. [PMID: 24926786 PMCID: PMC4057180 DOI: 10.1371/journal.pone.0099627] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 05/17/2014] [Indexed: 11/23/2022] Open
Abstract
Escherichia coli O157∶H7 is a mesophilic food-borne pathogen. We investigated the growth kinetics of E. coli O157∶H7 Sakai during an abrupt temperature downshift from 35°C to either 20°C, 17°C, 14°C or 10°C; as well as the molecular mechanisms enabling growth after cold stress upon an abrupt downshift from 35°C to 14°C in an integrated transcriptomic and proteomic analysis. All downshifts caused a lag period of growth before growth resumed at a rate typical of the post-shift temperature. Lag and generation time increased with the magnitude of the shift or with the final temperature, while relative lag time displayed little variation across the test range. Analysis of time-dependent molecular changes revealed, in keeping with a decreased growth rate at lower temperature, repression of genes and proteins involved in DNA replication, protein synthesis and carbohydrate catabolism. Consistent with cold-induced remodelling of the bacterial cell envelope, alterations occurred in the expression of genes and proteins involved in transport and binding. The RpoS regulon exhibited sustained induction confirming its importance in adaptation and growth at 14°C. The RpoE regulon was transiently induced, indicating a potential role for this extracytoplasmic stress response system in the early phase of low temperature adaptation during lag phase. Interestingly, genes previously reported to be amongst the most highly up-regulated under oxidative stress were consistently down-regulated. This comprehensive analysis provides insight into the molecular mechanisms operating during adaptation of E. coli to growth at low temperature and is relevant to its physiological state during chilling in foods, such as carcasses.
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Affiliation(s)
- Thea King
- Commonwealth Scientific and Industrial Research Organisation, Animal, Food and Health Sciences, North Ryde, New South Wales, Australia
- * E-mail:
| | - Chawalit Kocharunchitt
- Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Kari Gobius
- Commonwealth Scientific and Industrial Research Organisation, Animal, Food and Health Sciences, Werribee, Victoria, Australia
| | - John P. Bowman
- Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
| | - Tom Ross
- Food Safety Centre, Tasmanian Institute of Agriculture, University of Tasmania, Hobart, Tasmania, Australia
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Parisutham V, Jung SK, Nam D, Lee SK. Transcriptome-driven synthetic re-modeling of Escherichia coli to enhance cellobiose utilization. Chem Eng Sci 2013. [DOI: 10.1016/j.ces.2012.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Alternative sigma factor σE has an important role in stress tolerance of Yersinia pseudotuberculosis IP32953. Appl Environ Microbiol 2013; 79:5970-7. [PMID: 23872565 DOI: 10.1128/aem.01891-13] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yersinia pseudotuberculosis is an important pathogen that probably survives well in the modern food chain. However, little is known about the mechanisms that allow the growth of this pathogen in foods under stress conditions. The expression of rpoE encoding σ(E) was defined by quantitative real-time reverse transcription-PCR. Expression of rpoE was induced at 3°C, 37°C, and 42°C, under exposure to 3% NaCl, 3% ethanol, or high and low pH, in relation to its expression at the optimum growth temperature of 28°C of Y. pseudotuberculosis. Mutation of rpoE either impaired or abolished growth under stresses caused by low or high temperature, low pH, and ethanol. In addition, the growth temperature range of the mutant was significantly diminished compared to that of the wild-type strain IP32953. The results were confirmed with complementation of the mutant. Thus, σ(E) plays a significant role in the stress tolerance of Y. pseudotuberculosis IP32953 and probably contributes to the survival of this pathogen in the food chain.
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Obruca S, Snajdar O, Svoboda Z, Marova I. Application of random mutagenesis to enhance the production of polyhydroxyalkanoates by Cupriavidus necator H16 on waste frying oil. World J Microbiol Biotechnol 2013; 29:2417-28. [PMID: 23801326 DOI: 10.1007/s11274-013-1410-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 06/17/2013] [Indexed: 11/29/2022]
Abstract
Using random chemical mutagenesis we obtained the mutant of Cupriavidus necator H16 which was capable of improved (about 35 %) production of poly(3-hydroxybuytrate) (PHB) compared to the wild-type strain. The mutant exhibited significantly enhanced specific activities of enzymes involved in oxidative stress response such as malic enzyme, NADP-dependent isocitrate dehydrogenase, glucose-6-phosphate dehydrogenase and glutamate dehydrogenase. Probably, due to the activation of these enzymes, we also observed an increase of NADPH/NADP⁺ ratio. It is likely that as a side effect of the increase of NADPH/NADP⁺ ratio the activity of PHB biosynthetic pathway was enhanced, which supported the accumulation of PHB. Furthermore, the mutant was also able to incorporate propionate into copolymer poly(3-hydroxybuytyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] more efficiently than the wild-type strain (Y3HV/prec = 0.17 and 0.29 for the wild-type strain and the mutant, respectively)). We assume that it may be caused by lower availability of oxaloacetate for the utilization of propionyl-CoA in 2-methylcitrate cycle due to increased action of malic enzyme. Therefore, propionyl-CoA was incorporated into copolymer rather than transformed to pyruvate via 2-methylcitrate cycle. Thus, the mutant was capable of the utilization of waste frying oils and the production of P(3HB-co-3HV) with better yields and improved content of 3HV resulting in better mechanical properties of copolymer than the wild-type strain. The results of this work may be used for the development of innovative fermentation strategies for the production of PHA and also it might help to define novel targets for the genetic manipulations of PHA producing bacteria.
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Affiliation(s)
- Stanislav Obruca
- Materials Research Centre, Faculty of Chemistry, Brno University of Technology, Purkynova 118, 612 00, Brno, Czech Republic,
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Grube M, Dimanta I, Gavare M, Strazdina I, Liepins J, Juhna T, Kalnenieks U. Hydrogen-producing Escherichia coli strains overexpressing lactose permease: FT-IR analysis of the lactose-induced stress. Biotechnol Appl Biochem 2013; 61:111-7. [PMID: 23725289 DOI: 10.1002/bab.1128] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 05/22/2013] [Indexed: 11/07/2022]
Abstract
The lactose permease gene (lacY) was overexpressed in the septuple knockout mutant of Escherichia coli, previously engineered for hydrogen production from glucose. It was expected that raising the lactose transporter activity would elevate the intracellular lactose concentration, inactivate the lactose repressor, induce the lactose operon, and as a result stimulate overall lactose consumption and conversion. However, overexpression of the lactose transporter caused a considerable growth delay in the recombinant strain on lactose, resembling to some extent the "lactose killing" phenomenon. Therefore, the recombinant strain was subjected to selection on lactose-containing media. Selection on plates with 3% lactose yielded a strain with a decreased content of the recombinant plasmid but with an improved ability to grow and produce hydrogen on lactose. Macromolecular analysis of its biomass by means of Fourier transform-infrared spectroscopy demonstrated that increase of the cellular polysaccharide content might contribute to the adaptation of E. coli to lactose stress.
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Affiliation(s)
- Mara Grube
- Institute of Microbiology and Biotechnology, University of Latvia, Riga, Latvia; Department of Water Engineering and Technology, Riga Technical University, Riga, Latvia
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Saulou C, Jamme F, Girbal L, Maranges C, Fourquaux I, Cocaign-Bousquet M, Dumas P, Mercier-Bonin M. Synchrotron FTIR microspectroscopy of Escherichia coli at single-cell scale under silver-induced stress conditions. Anal Bioanal Chem 2013; 405:2685-97. [PMID: 23354575 DOI: 10.1007/s00216-013-6725-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/19/2012] [Accepted: 01/10/2013] [Indexed: 11/26/2022]
Abstract
The present work was focused on elucidating biochemical changes in the model bacterium Escherichia coli exposed to ionic silver mediated stress, at a single-cell scale. In order to achieve this, in situ synchrotron Fourier-transform infrared (sFTIR) microspectroscopy was performed, for the first time, on individual cells by attenuated total reflectance (ATR) combined with the use of zinc-selenide hemisphere for high spatial resolution. In a first part, the potential of the method was evaluated on bacteria subjected to a lethal 100 μM AgNO(3) concentration for 2 h compared to untreated 100 % viable cells. Differences in cell composition were assessed for the C-H stretching and protein spectral regions, indicating that the inhibitory action was targeted against both fatty acids and proteins. Transmission electron microscopy (TEM) confirmed morphological damages of the cell ultrastructure. The relevance of ATR-sFTIR microspectroscopy for highlighting the heterogeneity in Ag(+)-mediated effects within a given bacterial population was also pointed out. In a second part, cells were exposed to sub-lethal Ag(+) concentrations (<10 μM AgNO(3)) tested under "dynamic" growth mode: early addition vs. pulse in the mid-exponential phase, and compared to simultaneously batch-grown untreated bacteria or cells sampled just before the pulse, respectively. sFTIR microspectroscopy and TEM imaging were performed in close relation with growth kinetics characterization. No significant effect of the Ag(+) pulses was detected, in accordance with macrokinetics data. For early-treated cells, effects on fatty acid composition were shown, although no major alteration of protein secondary structure was noticed. These partial effects were consistent with TEM observations and growth kinetics.
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Affiliation(s)
- Claire Saulou
- Université de Toulouse, INSA, UPS, INPT, LISBP, Toulouse, France.
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Subminimal inhibitory concentrations of the disinfectant benzalkonium chloride select for a tolerant subpopulation of Escherichia coli with inheritable characteristics. Int J Mol Sci 2012; 13:4101-4123. [PMID: 22605968 PMCID: PMC3344204 DOI: 10.3390/ijms13044101] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/20/2012] [Accepted: 03/19/2012] [Indexed: 01/09/2023] Open
Abstract
Exposure of Escherichia coli to a subminimal inhibitory concentration (25% below MIC) of benzalkonium chloride (BC), an antimicrobial membrane-active agent commonly used in medical and food-processing environments, resulted in cell death and changes in cell morphology (filamentation). A small subpopulation (1–5% of the initial population) survived and regained similar morphology and growth rate as non-exposed cells. This subpopulation maintained tolerance to BC after serial transfers in medium without BC. To withstand BC during regrowth the cells up regulated a drug efflux associated gene (the acrB gene, member of the AcrAB-TolC efflux system) and changed expression of outer membrane porin genes (ompFW) and several genes involved in protecting the cell from the osmotic- and oxidative stress. Cells pre-exposed to osmotic- and oxidative stress (sodium chloride, salicylic acid and methyl viologen) showed higher tolerance to BC. A control and two selected isolates showing increased BC-tolerance after regrowth in BC was genome sequenced. No common point mutations were found in the BC- isolates but one point mutation in gene rpsA (Ribosomal protein S1) was observed in one of the isolates. The observed tolerance can therefore not solely be explained by the observed point mutation. The results indicate that there are several different mechanisms responsible for the regrowth of a tolerant subpopulation in BC, both BC-specific and general stress responses, and that sub-MIC of BC may select for phenotypic variants in a sensitive E. coli culture.
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Dimethyl sulfoxide and ethanol elicit increased amyloid biogenesis and amyloid-integrated biofilm formation in Escherichia coli. Appl Environ Microbiol 2012; 78:3369-78. [PMID: 22389366 DOI: 10.1128/aem.07743-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Escherichia coli directs the assembly of functional amyloid fibers termed "curli" that mediate adhesion and biofilm formation. We discovered that E. coli exhibits a tunable and selective increase in curli protein expression and fiber assembly in response to moderate concentrations of dimethyl sulfoxide (DMSO) and ethanol. Furthermore, the molecular alterations resulted in dramatic functional phenotypes associated with community behavior, including (i) cellular agglutination in broth, (ii) altered colony morphology, and (iii) increased biofilm formation. Solid-state nuclear magnetic resonance (NMR) spectra of intact pellicles formed in the presence of [(13)C(2)]DMSO confirmed that DMSO was not being transformed and utilized directly for metabolism. Collectively, the chemically induced phenotypes emphasize the plasticity of E. coli's response to environmental stimuli to enhance amyloid production and amyloid-integrated biofilm formation. The data also support our developing model of the extracellular matrix as an organized assembly of polymeric components, including amyloid fibers, in which composition relates to bacterial physiology and community function.
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Kocharunchitt C, King T, Gobius K, Bowman JP, Ross T. Integrated transcriptomic and proteomic analysis of the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions of cold and water activity stress. Mol Cell Proteomics 2012; 11:M111.009019. [PMID: 22008207 PMCID: PMC3270098 DOI: 10.1074/mcp.m111.009019] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An integrated transcriptomic and proteomic analysis was undertaken to determine the physiological response of Escherichia coli O157:H7 Sakai to steady-state conditions relevant to low temperature and water activity conditions experienced during meat carcass chilling in cold air. The response of E. coli during exponential growth at 25 °C a(w) 0.985, 14 °C a(w) 0.985, 25 °C a(w) 0.967, and 14 °C a(w) 0.967 was compared with that of a reference culture (35 °C a(w) 0.993). Gene and protein expression profiles of E. coli were more strongly affected by low water activity (a(w) 0.967) than by low temperature (14 °C). Predefined group enrichment analysis revealed that a universal response of E. coli to all test conditions included activation of the master stress response regulator RpoS and the Rcs phosphorelay system involved in the biosynthesis of the exopolysaccharide colanic acid, as well as down-regulation of elements involved in chemotaxis and motility. However, colanic acid-deficient mutants were shown to achieve comparable growth rates to their wild-type parents under all conditions, indicating that colanic acid is not required for growth. In contrast to the transcriptomic data, the proteomic data revealed that several processes involved in protein synthesis were down-regulated in overall expression at 14 °C a(w) 0.985, 25 °C a(w) 0.967, and 14 °C a(w) 0.967. This result suggests that during growth under these conditions, E. coli, although able to transcribe the required mRNA, may lack the cellular resources required for translation. Elucidating the global adaptive response of E. coli O157:H7 during exposure to chilling and water activity stress has provided a baseline of knowledge of the physiology of this pathogen.
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Affiliation(s)
- Chawalit Kocharunchitt
- Food Safety Centre, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart TAS 7001, Australia
| | - Thea King
- CSIRO Food and Nutritional Sciences, PO Box 52, North Ryde NSW 1670, Australia
| | - Kari Gobius
- CSIRO Food and Nutritional Sciences, PO Box 745, Archerfield BC QLD 4108, Australia
| | - John P Bowman
- Food Safety Centre, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart TAS 7001, Australia
| | - Tom Ross
- Food Safety Centre, Tasmanian Institute of Agricultural Research, School of Agricultural Science, University of Tasmania, Private Bag 54, Hobart TAS 7001, Australia.
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Palonen E, Lindström M, Karttunen R, Somervuo P, Korkeala H. Expression of signal transduction system encoding genes of Yersinia pseudotuberculosis IP32953 at 28°C and 3°C. PLoS One 2011; 6:e25063. [PMID: 21949852 PMCID: PMC3176822 DOI: 10.1371/journal.pone.0025063] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 08/26/2011] [Indexed: 11/18/2022] Open
Abstract
Yersinia pseudotuberculosis is a significant psychrotrophic food pathogen whose cold tolerance mechanisms are poorly understood. Signal transduction systems serve to monitor the environment, but no systematic investigation of their role at cold temperatures in Y. pseudotuberculosis has yet been undertaken. The relative expression levels of 54 genes predicted to encode proteins belonging to signal transduction systems in Y. pseudotuberculosis IP32953 were determined at 28°C and 3°C by quantitative real-time reverse transcription-PCR. The relative expression levels of 44 genes were significantly (p<0.05) higher at 3°C than at 28°C. Genes encoding the two-component system CheA/CheY had the highest relative expression levels at 3°C. Mutational analysis revealed that cheA is important for growth and motility at 3°C. The relative expression level of one gene, rssB, encoding an RpoS regulator, was significantly (p<0.05) lower at 3°C than at 28°C. The results suggest that several signal transduction systems might be used during growth at low temperature, and at least, CheA/CheY two-component system is important for low-temperature growth.
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Affiliation(s)
- Eveliina Palonen
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
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Alvarez-Ordóñez A, Mouwen DJM, López M, Prieto M. Fourier transform infrared spectroscopy as a tool to characterize molecular composition and stress response in foodborne pathogenic bacteria. J Microbiol Methods 2011; 84:369-78. [PMID: 21256893 DOI: 10.1016/j.mimet.2011.01.009] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/11/2011] [Indexed: 10/18/2022]
Abstract
Vibrational spectroscopy techniques have shown capacity to provide non-destructive, rapid, relevant information on microbial systematics, useful for classification and identification. Infrared spectroscopy enables the biochemical signatures from microbiological structures to be extracted and analyzed, in conjunction with advanced chemometrics. In addition, a number of recent studies have shown that Fourier Transform Infrared (FT-IR) spectroscopy can help understand the molecular basis of events such as the adaptive tolerance responses expressed by bacteria when exposed to stress conditions in the environment (e.g. those that cells confront in food and during food processing). The current review gives an overview of the published experimental techniques, data-processing algorithms and approaches used in FT-IR spectroscopy to assess the mechanisms of bacterial inactivation by food processing technologies and antimicrobial compounds, to monitor the spore and membrane properties of foodborne pathogens in changing environments, to detect stress-injured microorganisms in food-related environments, to assess dynamic changes in bacterial populations, and to study bacterial tolerance responses.
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Senger RS. Biofuel production improvement with genome-scale models: The role of cell composition. Biotechnol J 2010; 5:671-85. [DOI: 10.1002/biot.201000007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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