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Villalba de la Peña M, Kronholm I. Antimicrobial resistance in the wild: Insights from epigenetics. Evol Appl 2024; 17:e13707. [PMID: 38817397 PMCID: PMC11134192 DOI: 10.1111/eva.13707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 03/04/2024] [Accepted: 04/26/2024] [Indexed: 06/01/2024] Open
Abstract
Spreading of bacterial and fungal strains that are resistant to antimicrobials poses a serious threat to the well-being of humans, animals, and plants. Antimicrobial resistance has been mainly investigated in clinical settings. However, throughout their evolutionary history microorganisms in the wild have encountered antimicrobial substances, forcing them to evolve strategies to combat antimicrobial action. It is well known that many of these strategies are based on genetic mechanisms, but these do not fully explain important aspects of the antimicrobial response such as the rapid development of resistance, reversible phenotypes, and hetero-resistance. Consequently, attention has turned toward epigenetic pathways that may offer additional insights into antimicrobial mechanisms. The aim of this review is to explore the epigenetic mechanisms that confer antimicrobial resistance, focusing on those that might be relevant for resistance in the wild. First, we examine the presence of antimicrobials in natural settings. Then we describe the documented epigenetic mechanisms in bacteria and fungi associated with antimicrobial resistance and discuss innovative epigenetic editing techniques to establish causality in this context. Finally, we discuss the relevance of these epigenetic mechanisms on the evolutionary dynamics of antimicrobial resistance in the wild, emphasizing the critical role of priming in the adaptation process. We underscore the necessity of incorporating non-genetic mechanisms into our understanding of antimicrobial resistance evolution. These mechanisms offer invaluable insights into the dynamics of antimicrobial adaptation within natural ecosystems.
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Affiliation(s)
| | - Ilkka Kronholm
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
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2
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Jenniches L, Michaux C, Popella L, Reichardt S, Vogel J, Westermann AJ, Barquist L. Improved RNA stability estimation through Bayesian modeling reveals most Salmonella transcripts have subminute half-lives. Proc Natl Acad Sci U S A 2024; 121:e2308814121. [PMID: 38527194 PMCID: PMC10998600 DOI: 10.1073/pnas.2308814121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/16/2024] [Indexed: 03/27/2024] Open
Abstract
RNA decay is a crucial mechanism for regulating gene expression in response to environmental stresses. In bacteria, RNA-binding proteins (RBPs) are known to be involved in posttranscriptional regulation, but their global impact on RNA half-lives has not been extensively studied. To shed light on the role of the major RBPs ProQ and CspC/E in maintaining RNA stability, we performed RNA sequencing of Salmonella enterica over a time course following treatment with the transcription initiation inhibitor rifampicin (RIF-seq) in the presence and absence of these RBPs. We developed a hierarchical Bayesian model that corrects for confounding factors in rifampicin RNA stability assays and enables us to identify differentially decaying transcripts transcriptome-wide. Our analysis revealed that the median RNA half-life in Salmonella in early stationary phase is less than 1 min, a third of previous estimates. We found that over half of the 500 most long-lived transcripts are bound by at least one major RBP, suggesting a general role for RBPs in shaping the transcriptome. Integrating differential stability estimates with cross-linking and immunoprecipitation followed by RNA sequencing (CLIP-seq) revealed that approximately 30% of transcripts with ProQ binding sites and more than 40% with CspC/E binding sites in coding or 3' untranslated regions decay differentially in the absence of the respective RBP. Analysis of differentially destabilized transcripts identified a role for ProQ in the oxidative stress response. Our findings provide insights into posttranscriptional regulation by ProQ and CspC/E, and the importance of RBPs in regulating gene expression.
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Affiliation(s)
- Laura Jenniches
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
| | - Charlotte Michaux
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Linda Popella
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Sarah Reichardt
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
| | - Jörg Vogel
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
- Faculty of Medicine, University of Würzburg, Würzburg97080, Germany
| | - Alexander J. Westermann
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
- Institute of Molecular Infection Biology, University of Würzburg, Würzburg97080, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research, Helmholtz Centre for Infection Research, Würzburg97080, Germany
- Faculty of Medicine, University of Würzburg, Würzburg97080, Germany
- Department of Biology, University of Toronto Mississauga, Mississauga, ONL5L 1C6Canada
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3
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O’Connor PBF, Mahony J, Casey E, Baranov PV, van Sinderen D, Yordanova MM. Ribosome profiling reveals downregulation of UMP biosynthesis as the major early response to phage infection. Microbiol Spectr 2024; 12:e0398923. [PMID: 38451091 PMCID: PMC10986495 DOI: 10.1128/spectrum.03989-23] [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: 11/23/2023] [Accepted: 02/14/2024] [Indexed: 03/08/2024] Open
Abstract
Bacteria have evolved diverse defense mechanisms to counter bacteriophage attacks. Genetic programs activated upon infection characterize phage-host molecular interactions and ultimately determine the outcome of the infection. In this study, we applied ribosome profiling to monitor protein synthesis during the early stages of sk1 bacteriophage infection in Lactococcus cremoris. Our analysis revealed major changes in gene expression within 5 minutes of sk1 infection. Notably, we observed a specific and severe downregulation of several pyr operons which encode enzymes required for uridine monophosphate biosynthesis. Consistent with previous findings, this is likely an attempt of the host to starve the phage of nucleotides it requires for propagation. We also observed a gene expression response that we expect to benefit the phage. This included the upregulation of 40 ribosome proteins that likely increased the host's translational capacity, concurrent with a downregulation of genes that promote translational fidelity (lepA and raiA). In addition to the characterization of host-phage gene expression responses, the obtained ribosome profiling data enabled us to identify two putative recoding events as well as dozens of loci currently annotated as pseudogenes that are actively translated. Furthermore, our study elucidated alterations in the dynamics of the translation process, as indicated by time-dependent changes in the metagene profile, suggesting global shifts in translation rates upon infection. Additionally, we observed consistent modifications in the ribosome profiles of individual genes, which were apparent as early as 2 minutes post-infection. The study emphasizes our ability to capture rapid alterations of gene expression during phage infection through ribosome profiling. IMPORTANCE The ribosome profiling technology has provided invaluable insights for understanding cellular translation and eukaryotic viral infections. However, its potential for investigating host-phage interactions remains largely untapped. Here, we applied ribosome profiling to Lactococcus cremoris cultures infected with sk1, a major infectious agent in dairy fermentation processes. This revealed a profound downregulation of genes involved in pyrimidine nucleotide synthesis at an early stage of phage infection, suggesting an anti-phage program aimed at restricting nucleotide availability and, consequently, phage propagation. This is consistent with recent findings and contributes to our growing appreciation for the role of nucleotide limitation as an anti-viral strategy. In addition to capturing rapid alterations in gene expression levels, we identified translation occurring outside annotated regions, as well as signatures of non-standard translation mechanisms. The gene profiles revealed specific changes in ribosomal densities upon infection, reflecting alterations in the dynamics of the translation process.
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Affiliation(s)
- Patrick B. F. O’Connor
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
- EIRNA Bio, Bioinnovation Hub, Cork, Ireland
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Eoghan Casey
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Pavel V. Baranov
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
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4
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Seshan H, Santillan E, Constancias F, Chandra Segaran US, Williams RBH, Wuertz S. Metagenomics and metatranscriptomics suggest pathways of 3-chloroaniline degradation in wastewater reactors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166066. [PMID: 37549699 DOI: 10.1016/j.scitotenv.2023.166066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/23/2023] [Accepted: 08/03/2023] [Indexed: 08/09/2023]
Abstract
Biological wastewater treatment systems are often affected by shifts in influent quality, including the input of toxic chemicals. Yet the mechanisms underlying the adaptation of activated sludge process performance are rarely studied in a controlled and replicated experimental setting, particularly when challenged with a sustained toxin input. Three replicate bench-scale bioreactors were subjected to a chemical disturbance in the form of 3-chloroaniline (3-CA) over 132 days, after an acclimation period of 58 days, while three control reactors received no 3-CA input. Ammonia oxidation was initially affected by 3-CA. Within three weeks of the experiment, microbial communities in all three treatment reactors adapted to biologically degrade 3-CA resulting in partial ammonia oxidation recovery. Combining process and microbial community data from amplicon sequencing with potential functions gleaned from assembled metagenomics and metatranscriptomics data, two putative degradation pathways for 3-CA were identified. The first pathway, determined from metagenomics data, involves a benzoate dioxygenase and subsequent meta-cleavage of the aromatic ring. The second, determined from intensive short-term sampling for gene expression data in tandem with 3-CA degradation, involves a phenol monooxygenase followed by ortho-cleavage of the aromatic ring. The relative abundances of amplicon sequence variants associated with the genera Gemmatimonas, OLB8, and Taibaiella correlated significantly with 3-CA degradation. Metagenome-assembled genome data also showed the genus OLB8 to be differentially enriched in treatment reactors, making it a strong candidate as 3-CA degrader. Using replicated reactors, this study has demonstrated the impact of a sustained stress on the activated sludge process. The unique and novel features of this study include the identification of putative pathways and potential degraders of 3-CA using long-term and short-term sampling in tandem with multiple methods in a controlled and replicated experiment.
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Affiliation(s)
- Hari Seshan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA
| | - Ezequiel Santillan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA
| | - Florentin Constancias
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore
| | - Uma Shankari Chandra Segaran
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore
| | - Rohan B H Williams
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, 119077, Singapore
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551, Singapore; Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA; School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore..
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5
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Small I, Melonek J, Bohne AV, Nickelsen J, Schmitz-Linneweber C. Plant organellar RNA maturation. THE PLANT CELL 2023; 35:1727-1751. [PMID: 36807982 PMCID: PMC10226603 DOI: 10.1093/plcell/koad049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/05/2023] [Accepted: 01/17/2023] [Indexed: 05/30/2023]
Abstract
Plant organellar RNA metabolism is run by a multitude of nucleus-encoded RNA-binding proteins (RBPs) that control RNA stability, processing, and degradation. In chloroplasts and mitochondria, these post-transcriptional processes are vital for the production of a small number of essential components of the photosynthetic and respiratory machinery-and consequently for organellar biogenesis and plant survival. Many organellar RBPs have been functionally assigned to individual steps in RNA maturation, often specific to selected transcripts. While the catalog of factors identified is ever-growing, our knowledge of how they achieve their functions mechanistically is far from complete. This review summarizes the current knowledge of plant organellar RNA metabolism taking an RBP-centric approach and focusing on mechanistic aspects of RBP functions and the kinetics of the processes they are involved in.
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Affiliation(s)
- Ian Small
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Joanna Melonek
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Molecular Sciences, The University of Western Australia, Crawley 6009, Australia
| | | | - Jörg Nickelsen
- Department of Molecular Plant Sciences, LMU Munich, 82152 Martinsried, Germany
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6
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Wagner L, Jules M, Borkowski O. What remains from living cells in bacterial lysate-based cell-free systems. Comput Struct Biotechnol J 2023; 21:3173-3182. [PMID: 37333859 PMCID: PMC10275740 DOI: 10.1016/j.csbj.2023.05.025] [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: 03/15/2023] [Revised: 05/23/2023] [Accepted: 05/23/2023] [Indexed: 06/20/2023] Open
Abstract
Because they mimic cells while offering an accessible and controllable environment, lysate-based cell-free systems (CFS) have emerged as valuable biotechnology tools for synthetic biology. Historically used to uncover fundamental mechanisms of life, CFS are nowadays used for a multitude of purposes, including protein production and prototyping of synthetic circuits. Despite the conservation of fundamental functions in CFS like transcription and translation, RNAs and certain membrane-embedded or membrane-bound proteins of the host cell are lost when preparing the lysate. As a result, CFS largely lack some essential properties of living cells, such as the ability to adapt to changing conditions, to maintain homeostasis and spatial organization. Regardless of the application, shedding light on the black-box of the bacterial lysate is necessary to fully exploit the potential of CFS. Most measurements of the activity of synthetic circuits in CFS and in vivo show significant correlations because these only require processes that are preserved in CFS, like transcription and translation. However, prototyping circuits of higher complexity that require functions that are lost in CFS (cell adaptation, homeostasis, spatial organization) will not show such a good correlation with in vivo conditions. Both for prototyping circuits of higher complexity and for building artificial cells, the cell-free community has developed devices to reconstruct cellular functions. This mini-review compares bacterial CFS to living cells, focusing on functional and cellular process differences and the latest developments in restoring lost functions through complementation of the lysate or device engineering.
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7
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Wee LM, Tong AB, Florez Ariza AJ, Cañari-Chumpitaz C, Grob P, Nogales E, Bustamante CJ. A trailing ribosome speeds up RNA polymerase at the expense of transcript fidelity via force and allostery. Cell 2023; 186:1244-1262.e34. [PMID: 36931247 PMCID: PMC10135430 DOI: 10.1016/j.cell.2023.02.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 11/14/2022] [Accepted: 02/06/2023] [Indexed: 03/18/2023]
Abstract
In prokaryotes, translation can occur on mRNA that is being transcribed in a process called coupling. How the ribosome affects the RNA polymerase (RNAP) during coupling is not well understood. Here, we reconstituted the E. coli coupling system and demonstrated that the ribosome can prevent pausing and termination of RNAP and double the overall transcription rate at the expense of fidelity. Moreover, we monitored single RNAPs coupled to ribosomes and show that coupling increases the pause-free velocity of the polymerase and that a mechanical assisting force is sufficient to explain the majority of the effects of coupling. Also, by cryo-EM, we observed that RNAPs with a terminal mismatch adopt a backtracked conformation, while a coupled ribosome allosterically induces these polymerases toward a catalytically active anti-swiveled state. Finally, we demonstrate that prolonged RNAP pausing is detrimental to cell viability, which could be prevented by polymerase reactivation through a coupled ribosome.
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Affiliation(s)
- Liang Meng Wee
- QB3-Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Alexander B Tong
- QB3-Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Alfredo Jose Florez Ariza
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA
| | - Cristhian Cañari-Chumpitaz
- QB3-Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA
| | - Patricia Grob
- QB3-Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Eva Nogales
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Carlos J Bustamante
- QB3-Berkeley, Berkeley, CA, USA; Biophysics Graduate Group, University of California Berkeley, Berkeley, CA, USA; Department of Chemistry, University of California Berkeley, Berkeley, CA, USA; Department of Physics, University of California Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA; Kavli Energy Nanoscience Institute, Berkeley, CA, USA; Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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8
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Francis N, Behera MR, Natarajan K, Laishram RS. Tyrosine phosphorylation controlled poly(A) polymerase I activity regulates general stress response in bacteria. Life Sci Alliance 2023; 6:6/3/e202101148. [PMID: 36535710 PMCID: PMC9764084 DOI: 10.26508/lsa.202101148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/28/2022] [Accepted: 11/29/2022] [Indexed: 12/23/2022] Open
Abstract
RNA 3'-end polyadenylation that marks transcripts for degradation is implicated in general stress response in Escherichia coli Yet, the mechanism and regulation of poly(A) polymerase I (PAPI) in stress response are obscure. We show that pcnB (that encodes PAPI)-null mutation widely stabilises stress response mRNAs and imparts cellular tolerance to multiple stresses, whereas PAPI ectopic expression renders cells stress-sensitive. We demonstrate that there is a substantial loss of PAPI activity on stress exposure that functionally phenocopies pcnB-null mutation stabilising target mRNAs. We identify PAPI tyrosine phosphorylation at the 202 residue (Y202) that is enormously enhanced on stress exposure. This phosphorylation inhibits PAPI polyadenylation activity under stress. Consequentially, PAPI phosphodeficient mutation (tyrosine 202 to phenylalanine, Y202F) fails to stimulate mRNA expression rendering cells stress-sensitive. Bacterial tyrosine kinase Wzc phosphorylates PAPI-Y202 residue, and that wzc-null mutation renders cells stress-sensitive. Accordingly, wzc-null mutation has no effect on stress sensitivity in the presence of pcnB-null or pcnB-Y202F mutation. We also establish that PAPI phosphorylation-dependent stress tolerance mechanism is distinct and operates downstream of the primary stress regulator RpoS.
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Affiliation(s)
- Nimmy Francis
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India
| | - Malaya R Behera
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India.,Regional Centre for Biotechnology, Faridabad, India
| | - Kathiresan Natarajan
- Transdisciplinary Biology Program, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India
| | - Rakesh S Laishram
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum, India
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9
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Mullis MM, Selwyn JD, Kevorkian R, Tague ED, Castro HF, Campagna SR, Lloyd KG, Reese BK. Microbial survival mechanisms within serpentinizing Mariana forearc sediments. FEMS Microbiol Ecol 2023; 99:6985003. [PMID: 36631299 DOI: 10.1093/femsec/fiad003] [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: 02/23/2022] [Revised: 12/07/2022] [Accepted: 01/10/2023] [Indexed: 01/13/2023] Open
Abstract
Marine deep subsurface sediment is often a microbial environment under energy-limited conditions. However, microbial life has been found to persist and even thrive in deep subsurface environments. The Mariana forearc represents an ideal location for determining how microbial life can withstand extreme conditions including pH 10-12.5 and depleted nutrients. The International Ocean Discovery Program Expedition 366 to the Mariana Convergent Margin sampled three serpentinizing seamounts located along the Mariana forearc chain with elevated concentrations of methane, hydrogen, and sulfide. Across all three seamount summits, the most abundant transcripts were for cellular maintenance such as cell wall and membrane repair, and the most abundant metabolic pathways were the Entner-Doudoroff pathway and tricarboxylic acid cycle. At flank samples, sulfur cycling involving taurine assimilation dominated the metatranscriptomes. The in situ activity of these pathways was supported by the detection of their metabolic intermediates. All samples had transcripts from all three domains of Bacteria, Archaea, and Eukarya, dominated by Burkholderiales, Deinococcales, and Pseudomonales, as well as the fungal group Opisthokonta. All samples contained transcripts for aerobic methane oxidation (pmoABC) and denitrification (nirKS). The Mariana forearc microbial communities show activity not only consistent with basic survival mechanisms, but also coupled metabolic reactions.
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Affiliation(s)
- Megan M Mullis
- Life Sciences Department, Texas A&M University - Corpus Christi, Corpus Christi, TX, United States.,Dauphin Island Sea Lab, Mobile, AL, United States
| | - Jason D Selwyn
- Life Sciences Department, Texas A&M University - Corpus Christi, Corpus Christi, TX, United States
| | - Richard Kevorkian
- Microbiology Department, University of Tennessee, Knoxville, TN, United States
| | - Eric D Tague
- Microbiology Department, University of Tennessee, Knoxville, TN, United States
| | - Hector F Castro
- Microbiology Department, University of Tennessee, Knoxville, TN, United States.,Chemistry Department, UTK Biological and Small Molecule Mass Spectrometry Core, Knoxville, TN, United States
| | - Shawn R Campagna
- Microbiology Department, University of Tennessee, Knoxville, TN, United States.,Chemistry Department, UTK Biological and Small Molecule Mass Spectrometry Core, Knoxville, TN, United States
| | - Karen G Lloyd
- Microbiology Department, University of Tennessee, Knoxville, TN, United States
| | - Brandi Kiel Reese
- Dauphin Island Sea Lab, Mobile, AL, United States.,Marine Sciences Department, University of South Alabama, Mobile, AL, United States
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10
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Tomlinson BR, Denham GA, Torres NJ, Brzozowski RS, Allen JL, Jackson JK, Eswara PJ, Shaw LN. Assessing the Role of Cold-Shock Protein C: a Novel Regulator of Acinetobacter baumannii Biofilm Formation and Virulence. Infect Immun 2022; 90:e0037622. [PMID: 36121221 PMCID: PMC9584223 DOI: 10.1128/iai.00376-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a formidable opportunistic pathogen that is notoriously difficult to eradicate from hospital settings. This resilience is often attributed to a proclivity for biofilm formation, which facilitates a higher tolerance toward external stress, desiccation, and antimicrobials. Despite this, little is known regarding the mechanisms orchestrating A. baumannii biofilm formation. Here, we performed RNA sequencing (RNA-seq) on biofilm and planktonic populations for the multidrug-resistant isolate AB5075 and identified 438 genes with altered expression. To assess the potential role of genes upregulated within biofilms, we tested the biofilm-forming capacity of their respective mutants from an A. baumannii transposon library. In so doing, we uncovered 24 genes whose disruption led to reduced biofilm formation. One such element, cold shock protein C (cspC), had a highly mucoid colony phenotype, enhanced tolerance to polysaccharide degradation, altered antibiotic tolerance, and diminished adherence to abiotic surfaces. RNA-seq of the cspC mutant revealed 201 genes with altered expression, including the downregulation of pili and fimbria genes and the upregulation of multidrug efflux pumps. Using transcriptional arrest assays, it appears that CspC mediates its effects, at least in part, through RNA chaperone activity, influencing the half-life of several important transcripts. Finally, we show that CspC is required for survival during challenge by the human immune system and is key for A. baumannii dissemination and/or colonization during systemic infection. Collectively, our work identifies a cadre of new biofilm-associated genes within A. baumannii and provides unique insight into the global regulatory network of this emerging human pathogen.
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Affiliation(s)
- Brooke R. Tomlinson
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Grant A. Denham
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Nathanial J. Torres
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Robert S. Brzozowski
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Jessie L. Allen
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Jessica K. Jackson
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Prahathees J. Eswara
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Lindsey N. Shaw
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
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11
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Klanschnig M, Cserjan-Puschmann M, Striedner G, Grabherr R. CRISPRactivation-SMS, a message for PAM sequence independent gene up-regulation in Escherichia coli. Nucleic Acids Res 2022; 50:10772-10784. [PMID: 36134715 PMCID: PMC9561276 DOI: 10.1093/nar/gkac804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 08/10/2022] [Accepted: 09/08/2022] [Indexed: 12/26/2022] Open
Abstract
Governance of the endogenous gene regulatory network enables the navigation of cells towards beneficial traits for recombinant protein production. CRISPRactivation and interference provides the basis for gene expression modulation but is primarily applied in eukaryotes. Particularly the lack of wide-ranging prokaryotic CRISPRa studies might be attributed to intrinsic limitations of bacterial activators and Cas9 proteins. While bacterial activators need accurate spatial orientation and distancing towards the target promoter to be functional, Cas9-based CRISPR tools only bind sites adjacent to NGG PAM sequences. These circumstances hampered Cas9-guided activators from mediating the up-regulation of endogenous genes at precise positions in bacteria. We could overcome this limitation by combining the PAM independent Cas9 variant SpRY and a CRISPRa construct using phage protein MCP fused to transcriptional activator SoxS. This CRISPRa construct, referred to as SMS, was compared with previously reported CRISPRa constructs and showed up-regulation of a reporter gene library independent of its PAM sequence in Escherichia coli. We also demonstrated down-regulation and multi-gene expression control with SMS at non-NGG PAM sites. Furthermore, we successfully applied SMS to up-regulate endogenous genes, and transgenes at non-NGG PAM sites, which was impossible with the previous CRISPRa construct.
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Affiliation(s)
- Marco Klanschnig
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
| | - Reingard Grabherr
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, 1190 Vienna, Austria
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12
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Xiang X, Poli D, Degnan BM, Degnan SM. Ribosomal RNA-Depletion Provides an Efficient Method for Successful Dual RNA-Seq Expression Profiling of a Marine Sponge Holobiont. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:722-732. [PMID: 35895230 PMCID: PMC9385839 DOI: 10.1007/s10126-022-10138-8] [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: 04/11/2022] [Accepted: 06/29/2022] [Indexed: 06/15/2023]
Abstract
Investigations of host-symbiont interactions can benefit enormously from a complete and reliable holobiont gene expression profiling. The most efficient way to acquire holobiont transcriptomes is to perform RNA-Seq on both host and symbionts simultaneously. However, optimal methods for capturing both host and symbiont mRNAs are still under development, particularly when the host is a eukaryote and the symbionts are bacteria or archaea. Traditionally, poly(A)-enriched libraries have been used to capture eukaryotic mRNA, but the ability of this method to adequately capture bacterial mRNAs is unclear because of the short half-life of the bacterial transcripts. Here, we address this gap in knowledge with the aim of helping others to choose an appropriate RNA-Seq approach for analysis of animal host-bacterial symbiont transcriptomes. Specifically, we compared transcriptome bias, depth and coverage achieved by two different mRNA capture and sequencing strategies applied to the marine demosponge Amphimedon queenslandica holobiont. Annotated genomes of the sponge host and the three most abundant bacterial symbionts, which can comprise up to 95% of the adult microbiome, are available. Importantly, this allows for transcriptomes to be accurately mapped to these genomes, and thus quantitatively assessed and compared. The two strategies that we compare here are (i) poly(A) captured mRNA-Seq (Poly(A)-RNA-Seq) and (ii) ribosomal RNA depleted RNA-Seq (rRNA-depleted-RNA-Seq). For the host sponge, we find no significant difference in transcriptomes generated by the two different mRNA capture methods. However, for the symbiont transcriptomes, we confirm the expectation that the rRNA-depleted-RNA-Seq performs much better than the Poly(A)-RNA-Seq. This comparison demonstrates that RNA-Seq by ribosomal RNA depletion is an effective and reliable method to simultaneously capture gene expression in host and symbionts and thus to analyse holobiont transcriptomes.
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Affiliation(s)
- Xueyan Xiang
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
- Present Address: BGI-Shenzhen, Shenzhen, 518083 China
| | - Davide Poli
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
- Present Address: School of Biomedical Sciences, Queensland University of Technology, Brisbane, Australia
| | - Bernard M. Degnan
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
| | - Sandie M. Degnan
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072 Australia
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13
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Cellular RNA Targets of Cold Shock Proteins CspC and CspE and Their Importance for Serum Resistance in Septicemic Escherichia coli. mSystems 2022; 7:e0008622. [PMID: 35695420 PMCID: PMC9426608 DOI: 10.1128/msystems.00086-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The RNA chaperones, cold shock proteins CspC and CspE, are important in stress response and adaptation. We studied their role in the pathogenesis of a virulent Escherichia coli, representative of extraintestinal pathogenic E. coli (ExPEC) which are serum resistant and septicemic. We performed a global analysis to identify transcripts that interact with these cold shock proteins (CSPs), focusing on virulence-related genes. We used CLIP-seq, which combines UV cross-linking, immunoprecipitation and RNA sequencing. A large number of transcripts bound to the CSPs were identified, and many bind both CspC and CspE. Many transcripts were of genes involved in protein synthesis, transcription and energy metabolism. In addition, there were virulence-related genes, (i.e., fur and ryhB), essential for iron homeostasis. The CLIP-seq results were validated on two transcripts, clpX and tdcA, reported as virulence-associated. Deletion of either CspC or CspE significantly decreased their transcript levels and in a double deletion mutant cspC/cspE, the transcript stability of tdcA and clpX was reduced by 32-fold and 10-fold, respectively. We showed that these two genes are important for virulence, as deleting either of them resulted in loss of serum resistance, a requirement for sepsis. As several virulence-related transcripts interact with CspC or CspE, we determined the importance of these proteins for growth in serum and showed that deletion of either gene significantly reduced serum survival. This phenotype could be partially complemented by cspE and fully complemented by cspC. These results indicate that the two RNA chaperones are essential for virulence, and that CspC particularly critical. IMPORTANCE Virulent Escherichia coli strains that cause infections outside the intestinal tract—extraintestinal pathogenic E. coli (ExPEC)—constitute a major clinical problem worldwide. They are involved in several distinct conditions, including urinary tract infections, newborn meningitis, and sepsis. Due to increasing antibiotic resistance, these strains are a main factor in hospital and community-acquired infections. Because many strains, which do not cross-react immunologically are involved, developing a simple vaccine is not possible. Therefore, it is essential to understand the pathogenesis of these bacteria to identify potential targets for developing drugs or vaccines. One of the least investigated systems involves RNA binding proteins, important for stability of transcripts and global gene regulation. Two such proteins are CspC and CspE (“cold shock proteins”), RNA chaperones involved in stress adaptation. Here we performed a global analysis to identify the transcripts which are affected by these two chaperones, with focus on virulence-associated transcripts.
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14
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Chakaroun R, Massier L, Musat N, Kovacs P. New Paradigms for Familiar Diseases: Lessons Learned on Circulatory Bacterial Signatures in Cardiometabolic Diseases. Exp Clin Endocrinol Diabetes 2022; 130:313-326. [PMID: 35320847 DOI: 10.1055/a-1756-4509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Despite the strongly accumulating evidence for microbial signatures in metabolic tissues, including the blood, suggesting a novel paradigm for metabolic disease development, the notion of a core blood bacterial signature in health and disease remains a contentious concept. Recent studies clearly demonstrate that under a strict contamination-free environment, methods such as 16 S rRNA gene sequencing, fluorescence in-situ hybridization, transmission electron microscopy, and several more, allied with advanced bioinformatics tools, allow unambiguous detection and quantification of bacteria and bacterial DNA in human tissues. Bacterial load and compositional changes in the blood have been reported for numerous disease states, suggesting that bacteria and their components may partially induce systemic inflammation in cardiometabolic disease. This concept has been so far primarily based on measurements of surrogate parameters. It is now highly desirable to translate the current knowledge into diagnostic, prognostic, and therapeutic approaches.This review addresses the potential clinical relevance of a blood bacterial signature pertinent to cardiometabolic diseases and outcomes and new avenues for translational approaches. It discusses pitfalls related to research in low bacterial biomass while proposing mitigation strategies for future research and application approaches.
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Affiliation(s)
- Rima Chakaroun
- Medical Department III - Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany.,Wallenberg Laboratory, Department of Molecular and Clinical Medicine and Sahlgrenska Center for Cardiovascular and Metabolic Research, University of Gothenburg, Gothenburg, Sweden
| | - Lucas Massier
- Medical Department III - Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany.,Department of Medicine (H7), Karolinska Institutet, Stockholm, Sweden
| | - Niculina Musat
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Peter Kovacs
- Medical Department III - Endocrinology, Nephrology, Rheumatology, University of Leipzig Medical Center, Leipzig, Germany.,Deutsches Zentrum für Diabetesforschung eV, Neuherberg, Germany
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15
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Zhang J, Hess WR, Zhang C. "Life is short, and art is long": RNA degradation in cyanobacteria and model bacteria. MLIFE 2022; 1:21-39. [PMID: 38818322 PMCID: PMC10989914 DOI: 10.1002/mlf2.12015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/03/2022] [Accepted: 03/03/2022] [Indexed: 06/01/2024]
Abstract
RNA turnover plays critical roles in the regulation of gene expression and allows cells to respond rapidly to environmental changes. In bacteria, the mechanisms of RNA turnover have been extensively studied in the models Escherichia coli and Bacillus subtilis, but not much is known in other bacteria. Cyanobacteria are a diverse group of photosynthetic organisms that have great potential for the sustainable production of valuable products using CO2 and solar energy. A better understanding of the regulation of RNA decay is important for both basic and applied studies of cyanobacteria. Genomic analysis shows that cyanobacteria have more than 10 ribonucleases and related proteins in common with E. coli and B. subtilis, and only a limited number of them have been experimentally investigated. In this review, we summarize the current knowledge about these RNA-turnover-related proteins in cyanobacteria. Although many of them are biochemically similar to their counterparts in E. coli and B. subtilis, they appear to have distinct cellular functions, suggesting a different mechanism of RNA turnover regulation in cyanobacteria. The identification of new players involved in the regulation of RNA turnover and the elucidation of their biological functions are among the future challenges in this field.
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Affiliation(s)
- Ju‐Yuan Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of SciencesWuhanChina
| | - Wolfgang R. Hess
- Genetics and Experimental Bioinformatics, Faculty of BiologyUniversity of FreiburgFreiburgGermany
| | - Cheng‐Cai Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of HydrobiologyChinese Academy of SciencesWuhanChina
- Institut WUT‐AMUAix‐Marseille University and Wuhan University of TechnologyWuhanChina
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16
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Hernández-Álvarez C, García-Oliva F, Cruz-Ortega R, Romero MF, Barajas HR, Piñero D, Alcaraz LD. Squash root microbiome transplants and metagenomic inspection for in situ arid adaptations. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 805:150136. [PMID: 34818799 DOI: 10.1016/j.scitotenv.2021.150136] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 05/10/2023]
Abstract
Arid zones contain a diverse set of microbes capable of survival under dry conditions, some of which can form relationships with plants under drought stress conditions to improve plant health. We studied squash (Cucurbita pepo L.) root microbiome under historically arid and humid sites, both in situ and performing a common garden experiment. Plants were grown in soils from sites with different drought levels, using in situ collected soils as the microbial source. We described and analyzed bacterial diversity by 16S rRNA gene sequencing (N = 48) from the soil, rhizosphere, and endosphere. Proteobacteria were the most abundant phylum present in humid and arid samples, while Actinobacteriota abundance was higher in arid ones. The β-diversity analyses showed split microbiomes between arid and humid microbiomes, and aridity and soil pH levels could explain it. These differences between humid and arid microbiomes were maintained in the common garden experiment, showing that it is possible to transplant in situ diversity to the greenhouse. We detected a total of 1009 bacterial genera; 199 exclusively associated with roots under arid conditions. By 16S and shotgun metagenomics, we identified dry-associated taxa such as Cellvibrio, Ensifer adhaerens, and Streptomyces flavovariabilis. With shotgun metagenomic sequencing of rhizospheres (N = 6), we identified 2969 protein families in the squash core metagenome and found an increased number of exclusively protein families from arid (924) than humid samples (158). We found arid conditions enriched genes involved in protein degradation and folding, oxidative stress, compatible solute synthesis, and ion pumps associated with osmotic regulation. Plant phenotyping allowed us to correlate bacterial communities with plant growth. Our study revealed that it is possible to evaluate microbiome diversity ex-situ and identify critical species and genes involved in plant-microbe interactions in historically arid locations.
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Affiliation(s)
- Cristóbal Hernández-Álvarez
- Laboratorio de Genómica Ambiental, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico; Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Mexico
| | - Felipe García-Oliva
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Mexico
| | - Rocío Cruz-Ortega
- Departamento de Ecología Funcional, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico
| | - Miguel F Romero
- Laboratorio de Genómica Ambiental, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico
| | - Hugo R Barajas
- Laboratorio de Genómica Ambiental, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico
| | - Daniel Piñero
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico
| | - Luis D Alcaraz
- Laboratorio de Genómica Ambiental, Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México, Mexico.
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17
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Petrucci S, Costa C, Broyles D, Kaur A, Dikici E, Daunert S, Deo SK. Monitoring Pathogenic Viable E. coli O157:H7 in Food Matrices Based on the Detection of RNA Using Isothermal Amplification and a Paper-Based Platform. Anal Chem 2021; 94:2485-2492. [PMID: 34968033 DOI: 10.1021/acs.analchem.1c04305] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In recent years, the number of product recalls and contamination incidents involving pathogenic bacteria has significantly increased, and the ensuing infections continue to be an ongoing problem for public health and agriculture. Due to the widespread impact of these pathogens, there is a critical need for rapid, on-site assays that can provide rapid results. In this work, we demonstrate the development of a rapid and simple test based on the combination of reverse transcription with recombinase polymerase amplification followed by lateral flow strip detection of viable Escherichia coli O157:H7 cells by detecting the RNA of the pathogen. The optimized method can be performed for approximately 2 h with a detection limit of 10 CFU/mL of E. coli O157:H7 in buffer, spinach, and ground beef samples. Our assay is sensitive, detecting only E. coli O157:H7 and not nonpathogenic E. coli or other similar pathogens. This strategy was able to distinguish viable from nonviable bacteria and more significantly was able to detect viable but nonculturable bacteria, which is a major issue when using culture-based methods for monitoring pathogenic bacteria. An important advantage of this test is that it can provide timely identification and removal of contaminated consumables prior to distribution without an extensive sample preparation.
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Affiliation(s)
- Sabrina Petrucci
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
| | - Connor Costa
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
| | - David Broyles
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
| | - Avinash Kaur
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
| | - Emre Dikici
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
| | - Sylvia Daunert
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Clinical and Translational Science Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
| | - Sapna K Deo
- Department of Biochemistry and Molecular Biology, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States.,Dr. John T. MacDonald Foundation Biomedical Nanotechnology Institute, Miller School of Medicine, University of Miami, Miami, Florida 33136, United States
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18
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Walworth NG, Saito MA, Lee MD, McIlvin MR, Moran DM, Kellogg RM, Fu FX, Hutchins DA, Webb EA. Why Environmental Biomarkers Work: Transcriptome-Proteome Correlations and Modeling of Multistressor Experiments in the Marine Bacterium Trichodesmium. J Proteome Res 2021; 21:77-89. [PMID: 34855411 DOI: 10.1021/acs.jproteome.1c00517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ocean microbial communities are important contributors to the global biogeochemical reactions that sustain life on Earth. The factors controlling these communities are being increasingly explored using metatranscriptomic and metaproteomic environmental biomarkers. Using published proteomes and transcriptomes from the abundant colony-forming cyanobacterium Trichodesmium (strain IMS101) grown under varying Fe and/or P limitation in low and high CO2, we observed robust correlations of stress-induced proteins and RNAs (i.e., involved in transport and homeostasis) that yield useful information on the nutrient status under low and/or high CO2. Conversely, transcriptional and translational correlations of many other central metabolism pathways exhibit broad discordance. A cellular RNA and protein production/degradation model demonstrates how biomolecules with small initial inventories, such as environmentally responsive proteins, achieve large increases in fold-change units as opposed to those with a higher basal expression and inventory such as metabolic systems. Microbial cells, due to their immersion in the environment, tend to show large adaptive responses in both RNA and protein that result in transcript-protein correlations. These observations and model results demonstrate multi-omic coherence for environmental biomarkers and provide the underlying mechanism for those observations, supporting the promise for global application in detecting responses to environmental stimuli in a changing ocean.
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Affiliation(s)
- Nathan G Walworth
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Mak A Saito
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Michael D Lee
- Blue Marble Space Institute of Science, Seattle, Washington 98104, United States.,Exobiology Branch, NASA Ames Research Center, Moffett Field, California 94035, United States
| | - Matthew R McIlvin
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Dawn M Moran
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Riss M Kellogg
- Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States
| | - Fei-Xue Fu
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - David A Hutchins
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
| | - Eric A Webb
- Marine and Environmental Biology, Department of Biological Sciences, University of Southern California, Los Angeles, California 90089, United States
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19
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Induction of the Viable but Non-Culturable State in Salmonella Contaminating Dried Fruit. Appl Environ Microbiol 2021; 88:e0173321. [PMID: 34731057 PMCID: PMC8788685 DOI: 10.1128/aem.01733-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Salmonella can become viable but nonculturable (VBNC) in response to environmental stressors, but the induction of the VBNC state in Salmonella contaminating ready-to-eat dried fruit is poorly characterized. Dried apples, strawberries, and raisins were mixed with a five-strain cocktail of Salmonella at 4% volume per weight of dried fruit at 109 CFU/g. The inoculated dried fruit were then dried in desiccators at 25°C until the water activity (aw) approximated that of the uninoculated dried fruit. However, Salmonella could not be recovered after drying, not even after enrichment, suggesting a population reduction of approximately 8 log CFU/g. To assess the potential impact of storage temperature on survival, dried apples were spot-inoculated with the Salmonella cocktail, dried under ambient atmosphere at 25°C, and stored at 4 and 25°C. Spot inoculation permitted recovery of Salmonella on dried apple after drying, with the population of Salmonella decreasing progressively on dried apples stored at 25°C until it was undetectable after about 46 days, even following enrichment. The population decline was noticeably slower at 4°C, with Salmonella being detected until 82 days. However, fluorescence microscopy and laser scanning confocal microscopy with the LIVE/DEAD BacLight bacterial viability system at time points at which no Salmonella could be recovered on growth media even following enrichment showed that a large proportion (56 to 85%) of the Salmonella cells on the dried fruit were viable. The data suggest that the unique combination of stressors in dried fruit can induce large numbers of VBNC cells of Salmonella. IMPORTANCESalmonella is a leading foodborne pathogen globally causing numerous outbreaks of foodborne illnesses and remains the leading contributor to deaths attributed to foodborne disease in the United States and other industrialized nations. Therefore, efficient detection methods for Salmonella contaminating food are critical for public health and food safety. Culture-based microbiological methods are considered the gold standard for the detection and enumeration of Salmonella in food. Findings from this study suggest that unique stressors on dried fruit can induce the VBNC state in Salmonella, thus rendering it undetectable with culture-based methods even though the bacteria remain viable. Therefore, strong consideration should be given to using, in addition to culture-based methods, microscopic and molecular methods for the accurate detection of all viable and/or culturable cells of Salmonella contaminating dried fruit, as all of these cells have the potential to cause human illness.
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20
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Xiang Y, Surovtsev IV, Chang Y, Govers SK, Parry BR, Liu J, Jacobs-Wagner C. Interconnecting solvent quality, transcription, and chromosome folding in Escherichia coli. Cell 2021; 184:3626-3642.e14. [PMID: 34186018 DOI: 10.1016/j.cell.2021.05.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 12/09/2020] [Accepted: 05/25/2021] [Indexed: 12/12/2022]
Abstract
All cells fold their genomes, including bacterial cells, where the chromosome is compacted into a domain-organized meshwork called the nucleoid. How compaction and domain organization arise is not fully understood. Here, we describe a method to estimate the average mesh size of the nucleoid in Escherichia coli. Using nucleoid mesh size and DNA concentration estimates, we find that the cytoplasm behaves as a poor solvent for the chromosome when the cell is considered as a simple semidilute polymer solution. Monte Carlo simulations suggest that a poor solvent leads to chromosome compaction and DNA density heterogeneity (i.e., domain formation) at physiological DNA concentration. Fluorescence microscopy reveals that the heterogeneous DNA density negatively correlates with ribosome density within the nucleoid, consistent with cryoelectron tomography data. Drug experiments, together with past observations, suggest the hypothesis that RNAs contribute to the poor solvent effects, connecting chromosome compaction and domain formation to transcription and intracellular organization.
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Affiliation(s)
- Yingjie Xiang
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Ivan V Surovtsev
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Yunjie Chang
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Sander K Govers
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA; Department of Biology and Institute of Chemistry, Engineering and Medicine for Human Health, Stanford University, Palo Alto, CA 94305, USA
| | - Bradley R Parry
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Jun Liu
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA; Department of Biology and Institute of Chemistry, Engineering and Medicine for Human Health, Stanford University, Palo Alto, CA 94305, USA.
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21
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Trudel-Ferland M, Jubinville E, Jean J. Persistence of Hepatitis A Virus RNA in Water, on Non-porous Surfaces, and on Blueberries. Front Microbiol 2021; 12:618352. [PMID: 33613487 PMCID: PMC7890088 DOI: 10.3389/fmicb.2021.618352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/15/2021] [Indexed: 11/17/2022] Open
Abstract
Enteric viruses, such as human norovirus and hepatitis A virus (HAV), are the leading cause of transmissible foodborne illness. Fresh produce such as berries are often contaminated by infected food handlers, soiled water, or food contact surfaces. The gold-standard method for virus detection throughout the food chain is RT-qPCR, which detects portions of genomes including non-infectious viral particles and naked viral RNA. The aim of this study was to evaluate the persistence of heat-inactivated HAV in water, phosphate-buffered saline, on stainless steel and polyvinyl chloride, and on blueberries at −80°C, −20°C, 4°C, and room temperature. In water and phosphate-buffered saline, viral RNA could be detected for up to 90 days regardless of temperature when the initial load was 2.5 × 104 or 2.5 × 106 genome copies. It was detected on polyvinyl chloride and blueberries under most conditions. On stainless steel, the large initial load persisted for 90 days, while the medium-level load was detected only up to 16 days at room temperature or 60 days at 4°C. The detection of non-infectious viral RNA can confound investigations of gastroenteritis outbreaks. Pretreatments that discriminate between naked RNA, non-infectious virions and infectious virions need to be included in the RT-qPCR method in order to reduce the risk of positive results associated with non-infectious viral particles.
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Affiliation(s)
- Mathilde Trudel-Ferland
- Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec City, QC, Canada
| | - Eric Jubinville
- Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec City, QC, Canada
| | - Julie Jean
- Institute of Nutrition and Functional Foods (INAF), Université Laval, Quebec City, QC, Canada
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22
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Salazar AM, Leisgang AM, Ortiz AA, Murtishaw AS, Kinney JW. Alterations of GABA B receptors in the APP/PS1 mouse model of Alzheimer's disease. Neurobiol Aging 2020; 97:129-143. [PMID: 33232936 DOI: 10.1016/j.neurobiolaging.2020.10.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 09/08/2020] [Accepted: 10/16/2020] [Indexed: 01/20/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the progressive decline of memory and cognitive function. The disease is characterized by the presence of amyloid plaques, tau tangles, altered inflammatory signaling, and alterations in numerous neurotransmitter signaling systems, including γ-aminobutyric acid (GABA). Given the extensive role of GABA in regulating neuronal activity, a careful investigation of GABA-related changes is needed. Further, given persistent inflammation has been demonstrated to drive AD pathology, the presence of GABA B receptor expressed on glia that serve a role regulation of the immune response adds to potential implications of altered GABA in AD. There has not previously been a systematic evaluation of GABA-related changes in an amyloid model of AD that specifically focuses on examining changes in GABA B receptors. In the present study, we examined alterations in several GABA-specific targets in the APP/PS1 mouse model at different ages. In the 4-month-old cohort, no significant deficits in spatial learning and memory or alterations in any of the GABAergic targets were observed compared with wild-type controls. However, we identified significant alterations in several GABA-related targets in the 6-month-old cohort that exhibited spatial learning deficits that include changes in glutamic acid decarboxylase 65, GABA transporter type 3, and GABA B receptors protein and mRNA levels. This was the same cohort at which learning and memory deficits and significant amyloid pathology was observed. Overall, our study provides evidence of altered GABAergic signaling in an amyloid model of AD at a time point consistent with AD-related deficits.
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Affiliation(s)
- Arnold M Salazar
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Amanda M Leisgang
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Andrew A Ortiz
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Andrew S Murtishaw
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Jefferson W Kinney
- Department of Brain Health, School of Integrated Health Sciences, University of Nevada Las Vegas, Las Vegas, NV, USA.
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Vargas-Blanco DA, Shell SS. Regulation of mRNA Stability During Bacterial Stress Responses. Front Microbiol 2020; 11:2111. [PMID: 33013770 PMCID: PMC7509114 DOI: 10.3389/fmicb.2020.02111] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
Bacteria have a remarkable ability to sense environmental changes, swiftly regulating their transcriptional and posttranscriptional machinery as a response. Under conditions that cause growth to slow or stop, bacteria typically stabilize their transcriptomes in what has been shown to be a conserved stress response. In recent years, diverse studies have elucidated many of the mechanisms underlying mRNA degradation, yet an understanding of the regulation of mRNA degradation under stress conditions remains elusive. In this review we discuss the diverse mechanisms that have been shown to affect mRNA stability in bacteria. While many of these mechanisms are transcript-specific, they provide insight into possible mechanisms of global mRNA stabilization. To that end, we have compiled information on how mRNA fate is affected by RNA secondary structures; interaction with ribosomes, RNA binding proteins, and small RNAs; RNA base modifications; the chemical nature of 5' ends; activity and concentration of RNases and other degradation proteins; mRNA and RNase localization; and the stringent response. We also provide an analysis of reported relationships between mRNA abundance and mRNA stability, and discuss the importance of stress-associated mRNA stabilization as a potential target for therapeutic development.
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Affiliation(s)
- Diego A Vargas-Blanco
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Scarlet S Shell
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States.,Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA, United States
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24
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Wirsching J, Pagel H, Ditterich F, Uksa M, Werneburg M, Zwiener C, Berner D, Kandeler E, Poll C. Biodegradation of Pesticides at the Limit: Kinetics and Microbial Substrate Use at Low Concentrations. Front Microbiol 2020; 11:2107. [PMID: 32983068 PMCID: PMC7481373 DOI: 10.3389/fmicb.2020.02107] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 08/10/2020] [Indexed: 11/15/2022] Open
Abstract
The objective of our study was to test whether limited microbial degradation at low pesticide concentrations could explain the discrepancy between overall degradability demonstrated in laboratory tests and their actual persistence in the environment. Studies on pesticide degradation are often performed using unrealistically high application rates seldom found in natural environments. Nevertheless, biodegradation rates determined for higher pesticide doses cannot necessarily be extrapolated to lower concentrations. In this context, we wanted to (i) compare the kinetics of pesticide degradation at different concentrations in arable land and (ii) clarify whether there is a concentration threshold below which the expression of the functional genes involved in the degradation pathway is inhibited without further pesticide degradation taking place. We set up an incubation experiment for four weeks using 14C-ring labeled 2-methyl-4-chlorophenoxyacetic acid (MCPA) as a model compound in concentrations from 30 to 20,000 μg kg–1 soil. To quantify the abundance of putative microorganisms involved in MCPA degradation and their degradation activity, tfdA gene copy numbers (DNA) and transcripts (mRNA) were determined by quantitative real-time PCR. Mineralization dynamics of MCPA derived-C were analyzed by monitoring 14CO2 production and 14C assimilation by soil microorganisms. We identified two different concentration thresholds for growth and activity with respect to MCPA degradation using tfdA gene and mRNA transcript abundance as growth and activity indices, respectively. The tfdA gene expression started to increase between 1,000 and 5,000 μg MCPA kg–1 dry soil, but an actual increase in tfdA sequences could only be determined at a concentration of 20,000 μg. Accordingly, we observed a clear shift from catabolic to anabolic utilization of MCPA-derived C in the concentration range of 1,000 to 5,000 μg kg–1. Concentrations ≥1,000 μg kg–1 were mainly associated with delayed mineralization, while concentrations ≤1,000 μg kg–1 showed rapid absolute dissipation. The persistence of pesticides at low concentrations cannot, therefore, be explained by the absence of functional gene expression. Nevertheless, significant differences in the degradation kinetics of MCPA between low and high pesticide concentrations illustrate the need for studies investigating pesticide degradation at environmentally relevant concentrations.
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Affiliation(s)
- Johannes Wirsching
- Department of Soil Biology, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Holger Pagel
- Department of Soil Physics, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Franziska Ditterich
- Department of Soil Biology, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Marie Uksa
- Department of Soil Biology, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Martina Werneburg
- Department of Environmental Analytical Chemistry, Institute of Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Christian Zwiener
- Department of Environmental Analytical Chemistry, Institute of Applied Geoscience, University of Tübingen, Tübingen, Germany
| | - Doreen Berner
- Department of Soil Biology, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Ellen Kandeler
- Department of Soil Biology, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
| | - Christian Poll
- Department of Soil Biology, Institute of Soil Science and Land Evaluation, University of Hohenheim, Stuttgart, Germany
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25
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Molecular causes of an evolutionary shift along the parasitism-mutualism continuum in a bacterial symbiont. Proc Natl Acad Sci U S A 2020; 117:21658-21666. [PMID: 32817434 PMCID: PMC7474615 DOI: 10.1073/pnas.2005536117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Symbiotic relationships with microbes are ubiquitous among living beings and can be parasitic, such as in bacterial pathogens, or mutualistic, as in beneficial microbiomes. Among other factors, the outcome of microbe–host relationships is determined by the mode of symbiont transmission from host to host. Here we describe how bacterial symbionts increased in infectivity and virulence toward their amoeba host when transmission to a new host was essential for survival. The enhanced parasitism is a result of genomic changes and a pronounced switch of gene expression altering the symbionts’ mechanisms for host interaction. Our study provides both a molecular explanation as well as a blueprint for how changes in gene expression are sufficient to confer enhanced parasitism in microbes. Symbiosis with microbes is a ubiquitous phenomenon with a massive impact on all living organisms, shaping the world around us today. Theoretical and experimental studies show that vertical transmission of symbionts leads to the evolution of mutualistic traits, whereas horizontal transmission facilitates the emergence of parasitic features. However, these studies focused on phenotypic data, and we know little about underlying molecular changes at the genomic level. Here, we combined an experimental evolution approach with infection assays, genome resequencing, and global gene expression analysis to study the effect of transmission mode on an obligate intracellular bacterial symbiont. We show that a dramatic shift in the frequency of genetic variants, coupled with major changes in gene expression, allow the symbiont to alter its position in the parasitism–mutualism continuum depending on the mode of between-host transmission. We found that increased parasitism in horizontally transmitted chlamydiae residing in amoebae was a result of processes occurring at the infectious stage of the symbiont’s developmental cycle. Specifically, genes involved in energy production required for extracellular survival and the type III secretion system—the symbiont’s primary virulence mechanism—were significantly up-regulated. Our results identify the genomic and transcriptional dynamics sufficient to favor parasitic or mutualistic strategies.
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Yu Y, O'Rourke A, Lin YH, Singh H, Eguez RV, Beyhan S, Nelson KE. Predictive Signatures of 19 Antibiotic-Induced Escherichia coli Proteomes. ACS Infect Dis 2020; 6:2120-2129. [PMID: 32673475 DOI: 10.1021/acsinfecdis.0c00196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Identifying the mode of action (MOA) of antibacterial compounds is the fundamental basis for the development of new antibiotics, and the challenge increases with the emerging secondary and indirect effect from antibiotic stress. Although various omics-based system biology approaches are currently available, enhanced throughput, accuracy, and comprehensiveness are still desirable to better define antibiotic MOA. Using label-free quantitative proteomics, we present here a comprehensive reference map of proteomic signatures of Escherichia coli under challenge of 19 individual antibiotics. Applying several machine learning techniques, we derived a panel of 14 proteins that can be used to classify the antibiotics into different MOAs with nearly 100% accuracy. These proteins tend to mediate diverse bacterial cellular and metabolic processes. Transcriptomic level profiling correlates well with protein expression changes in discriminating different antibiotics. The reported expression signatures will aid future studies in identifying MOA of unknown compounds and facilitate the discovery of novel antibiotics.
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Affiliation(s)
- Yanbao Yu
- J. Craig Venter Institute, 9605 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Aubrie O'Rourke
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, California 92037, United States
| | - Yi-Han Lin
- J. Craig Venter Institute, 9605 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Harinder Singh
- J. Craig Venter Institute, 9605 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Rodrigo Vargas Eguez
- J. Craig Venter Institute, 9605 Medical Center Drive, Rockville, Maryland 20850, United States
| | - Sinem Beyhan
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, California 92037, United States
| | - Karen E Nelson
- J. Craig Venter Institute, 9605 Medical Center Drive, Rockville, Maryland 20850, United States
- J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, California 92037, United States
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27
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The Chloroplast RNA Binding Protein CP31A Has a Preference for mRNAs Encoding the Subunits of the Chloroplast NAD(P)H Dehydrogenase Complex and Is Required for Their Accumulation. Int J Mol Sci 2020; 21:ijms21165633. [PMID: 32781615 PMCID: PMC7460601 DOI: 10.3390/ijms21165633] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/16/2020] [Accepted: 08/04/2020] [Indexed: 01/15/2023] Open
Abstract
Chloroplast RNA processing requires a large number of nuclear-encoded RNA binding proteins (RBPs) that are imported post-translationally into the organelle. Most of these RBPs are highly specific for one or few target RNAs. By contrast, members of the chloroplast ribonucleoprotein family (cpRNPs) have a wider RNA target range. We here present a quantitative analysis of RNA targets of the cpRNP CP31A using digestion-optimized RNA co-immunoprecipitation with deep sequencing (DO-RIP-seq). This identifies the mRNAs coding for subunits of the chloroplast NAD(P)H dehydrogenase (NDH) complex as main targets for CP31A. We demonstrate using whole-genome gene expression analysis and targeted RNA gel blot hybridization that the ndh mRNAs are all down-regulated in cp31a mutants. This diminishes the activity of the NDH complex. Our findings demonstrate how a chloroplast RNA binding protein can combine functionally related RNAs into one post-transcriptional operon.
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28
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Abstract
RNA degradation is an important process that affects the final concentration of individual mRNAs, affecting protein expression and cellular physiology. Studies of how RNA is degraded increase our knowledge of this fundamental process as well as enable the creation of genetic tools to manipulate RNA stability. By studying global transcript turnover, we searched for sequence elements that correlated with transcript (in)stability and used these sequences to guide tool design. This study probes global RNA turnover in a cyanobacterium, Synechococcus sp. strain PCC 7002, that both has a unique array of RNases that facilitate RNA degradation and is an industrially relevant strain that could be used to convert CO2 and sunlight into useful products. RNA degradation is an important process that influences the ultimate concentration of individual proteins inside cells. While the main enzymes that facilitate this process have been identified, global maps of RNA turnover are available for only a few species. Even in these cases, there are few sequence elements that are known to enhance or destabilize a native transcript; even fewer confer the same effect when added to a heterologous transcript. To address this knowledge gap, we assayed genome-wide RNA degradation in the cyanobacterium Synechococcus sp. strain PCC 7002 by collecting total RNA samples after stopping nascent transcription with rifampin. We quantified the abundance of each position in the transcriptome as a function of time using RNA-sequencing data and later analyzed the global mRNA decay map using machine learning principles. Half-lives, calculated on a per-ORF (open reading frame) basis, were extremely short, with a median half-life of only 0.97 min. Despite extremely rapid turnover of most mRNA, transcripts encoding proteins involved in photosynthesis were both highly expressed and highly stable. Upon inspection of these stable transcripts, we identified an enriched motif in the 3′ untranslated region (UTR) that had similarity to Rho-independent terminators. We built statistical models for half-life prediction and used them to systematically identify sequence motifs in both 5′ and 3′ UTRs that correlate with stabilized transcripts. We found that transcripts linked to a terminator containing a poly(U) tract had a longer half-life than both those without a poly(U) tract and those without a terminator. IMPORTANCE RNA degradation is an important process that affects the final concentration of individual mRNAs, affecting protein expression and cellular physiology. Studies of how RNA is degraded increase our knowledge of this fundamental process as well as enable the creation of genetic tools to manipulate RNA stability. By studying global transcript turnover, we searched for sequence elements that correlated with transcript (in)stability and used these sequences to guide tool design. This study probes global RNA turnover in a cyanobacterium, Synechococcus sp. strain PCC 7002, that both has a unique array of RNases that facilitate RNA degradation and is an industrially relevant strain that could be used to convert CO2 and sunlight into useful products.
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29
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Perez-Carrasco R, Beentjes C, Grima R. Effects of cell cycle variability on lineage and population measurements of messenger RNA abundance. J R Soc Interface 2020; 17:20200360. [PMID: 32634365 PMCID: PMC7423421 DOI: 10.1098/rsif.2020.0360] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 06/17/2020] [Indexed: 12/17/2022] Open
Abstract
Many models of gene expression do not explicitly incorporate a cell cycle description. Here, we derive a theory describing how messenger RNA (mRNA) fluctuations for constitutive and bursty gene expression are influenced by stochasticity in the duration of the cell cycle and the timing of DNA replication. Analytical expressions for the moments show that omitting cell cycle duration introduces an error in the predicted mean number of mRNAs that is a monotonically decreasing function of η, which is proportional to the ratio of the mean cell cycle duration and the mRNA lifetime. By contrast, the error in the variance of the mRNA distribution is highest for intermediate values of η consistent with genome-wide measurements in many organisms. Using eukaryotic cell data, we estimate the errors in the mean and variance to be at most 3% and 25%, respectively. Furthermore, we derive an accurate negative binomial mixture approximation to the mRNA distribution. This indicates that stochasticity in the cell cycle can introduce fluctuations in mRNA numbers that are similar to the effect of bursty transcription. Finally, we show that for real experimental data, disregarding cell cycle stochasticity can introduce errors in the inference of transcription rates larger than 10%.
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Affiliation(s)
- Ruben Perez-Carrasco
- Department of Mathematics, University College London, London, UK
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Ramon Grima
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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30
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Bush JT, Chan MC, Mohammed S, Schofield CJ. Quantitative MS-Based Proteomics: Comparing the MCF-7 Cellular Response to Hypoxia and a 2-Oxoglutarate Analogue. Chembiochem 2020; 21:1647-1655. [PMID: 31919953 PMCID: PMC7317498 DOI: 10.1002/cbic.201900719] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Indexed: 12/19/2022]
Abstract
The hypoxia-inducible factors (HIFs) are key transcription factors in determining cellular responses involving alterations in protein levels in response to limited oxygen availability in animal cells. 2-Oxoglutarate-dependent oxygenases play key roles in regulating levels of HIF and its transcriptional activity. We describe MS-based proteomics studies in which we compared the results of subjecting human breast cancer MCF-7 cells to hypoxia or treating them with a cell-penetrating derivative (dimethyl N-oxalylglycine; DMOG) of the stable 2OG analogue N-oxalylglycine. The proteomic results are consistent with reported transcriptomic analyses and support the proposed key roles of 2OG-dependent HIF prolyl- and asparaginyl-hydroxylases in the hypoxic response. Differences between the data sets for hypoxia and DMOG might reflect context-dependent effects or HIF-independent effects of DMOG.
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Affiliation(s)
- Jacob T. Bush
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
- Current address: GSKMedicines Research CentreGunnels Wood RoadStevenageSG1 2NYUK
| | - Mun Chiang Chan
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
- Current address: Department of Molecular MedicineFaculty of MedicineUniversity of Malaya, Jalan Universiti50603Kuala LumpurMalaysia
| | - Shabaz Mohammed
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
- Department of BiochemistryUniversity of OxfordSouth Parks RoadOxfordOX1 3QUUK
| | - Christopher J. Schofield
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
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Bhagdikar D, Grundy FJ, Henkin TM. Transcriptional and translational S-box riboswitches differ in ligand-binding properties. J Biol Chem 2020; 295:6849-6860. [PMID: 32209653 DOI: 10.1074/jbc.ra120.012853] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/20/2020] [Indexed: 01/27/2023] Open
Abstract
There are a number of riboswitches that utilize the same ligand-binding domain to regulate transcription or translation. S-box (SAM-I) riboswitches, including the riboswitch present in the Bacillus subtilis metI gene, which encodes cystathionine γ-synthase, regulate the expression of genes involved in methionine metabolism in response to SAM, primarily at the level of transcriptional attenuation. A rarer class of S-box riboswitches is predicted to regulate translation initiation. Here we identified and characterized a translational S-box riboswitch in the metI gene from Desulfurispirillum indicum The regulatory mechanisms of riboswitches are influenced by the kinetics of ligand interaction. The half-life of the translational D. indicum metI RNA-SAM complex is significantly shorter than that of the transcriptional B. subtilis metI RNA. This finding suggests that, unlike the transcriptional RNA, the translational metI riboswitch can make multiple reversible regulatory decisions. Comparison of both RNAs revealed that the second internal loop of helix P3 in the transcriptional RNA usually contains an A residue, whereas the translational RNA contains a C residue that is conserved in other S-box RNAs that are predicted to regulate translation. Mutational analysis indicated that the presence of an A or C residue correlates with RNA-SAM complex stability. Biochemical analyses indicate that the internal loop sequence critically determines the stability of the RNA-SAM complex by influencing the flexibility of residues involved in SAM binding and thereby affects the molecular mechanism of riboswitch function.
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Affiliation(s)
- Divyaa Bhagdikar
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
| | - Frank J Grundy
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
| | - Tina M Henkin
- Department of Microbiology and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210
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32
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Edwards A, Cameron KA, Cook JM, Debbonaire AR, Furness E, Hay MC, Rassner SM. Microbial genomics amidst the Arctic crisis. Microb Genom 2020; 6:e000375. [PMID: 32392124 PMCID: PMC7371112 DOI: 10.1099/mgen.0.000375] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/16/2020] [Indexed: 12/16/2022] Open
Abstract
The Arctic is warming - fast. Microbes in the Arctic play pivotal roles in feedbacks that magnify the impacts of Arctic change. Understanding the genome evolution, diversity and dynamics of Arctic microbes can provide insights relevant for both fundamental microbiology and interdisciplinary Arctic science. Within this synthesis, we highlight four key areas where genomic insights to the microbial dimensions of Arctic change are urgently required: the changing Arctic Ocean, greenhouse gas release from the thawing permafrost, 'biological darkening' of glacial surfaces, and human activities within the Arctic. Furthermore, we identify four principal challenges that provide opportunities for timely innovation in Arctic microbial genomics. These range from insufficient genomic data to develop unifying concepts or model organisms for Arctic microbiology to challenges in gaining authentic insights to the structure and function of low-biomass microbiota and integration of data on the causes and consequences of microbial feedbacks across scales. We contend that our insights to date on the genomics of Arctic microbes are limited in these key areas, and we identify priorities and new ways of working to help ensure microbial genomics is in the vanguard of the scientific response to the Arctic crisis.
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Affiliation(s)
- Arwyn Edwards
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Karen A. Cameron
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Joseph M. Cook
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Aliyah R. Debbonaire
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Eleanor Furness
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Melanie C. Hay
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
| | - Sara M.E. Rassner
- Interdisciplinary Centre for Environmental Microbiology, Institute of Biological, Environmental and Rural Sciences, Cledwyn Building, Aberystwyth University, Cymru SY23 3DD, UK
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33
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Frayne EG. Global profile changes in transcripts induced with a phosphate analogue: implications for gene regulation. Mol Cell Biochem 2020; 468:111-120. [PMID: 32172469 DOI: 10.1007/s11010-020-03715-9] [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: 11/03/2019] [Accepted: 03/06/2020] [Indexed: 11/25/2022]
Abstract
Previous work has shown that thiophosphate, a phosphate analogue, leads to a global shift in the distribution of cellular proteins in a variety of organisms. Thiophosphate, when added to culture media, gets incorporated into the nucleic acids of cells resulting in nuclease-resistant phosphorothioate linkages. Using Escherichia coli, as a model organism, it was found that the global changes in protein expression induced with thiophosphate could be accounted for by significant changes in the absolute transcription levels of more than 1500 genes detected via RNA seq analysis. In fact, 58% of transcripts detected in RNA seq studies using total RNA were increased an average of 44 × fold while the remaining 42% were decreased an average of 20 × fold in thiophosphate-treated cells. Furthermore, microarray results showed no correlation between the transcriptional changes observed and the known stability of the corresponding mRNAs measured. Overall, the total amount of non-ribosomal RNA accumulated in TP-treated cells was increased relative to rRNA ~ 4 × fold (1.5-6 ×). The results further indicated that metabolic changes may play a role in inducing the transcriptional profiles observed with thiophosphate. Indeed, pathway analysis of transcripts showed an increase in routes for phosphoribosyl pyrophosphate (PRPP) synthesis and related derivatives, presumably due to a reduction in RNA turnover. These results raise the possibility that the energy savings with reduced RNA turnover could lead to an increased energy charge in the cell that induces transcriptional changes leading to an increase in biosynthetic processes.
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34
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Bead-based assay for spatiotemporal gene expression control in cell-free transcription-translation systems. Biotechniques 2020; 66:29-33. [PMID: 30730208 DOI: 10.2144/btn-2018-0097] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cell-free gene expression has applications in synthetic biology, biotechnology and biomedicine. In this technique gene expression regulation plays an important role. Transcription factors do not completely suppress expression while other methods for expression control, for example CRISPR/Cas, often require important biochemical modifications. Here we use an all Escherichia coli-based cell-free expression system and present a bead-based method to instantly start and, at a later stage, completely stop gene expression. Magnetic beads coated with DNA of the gene of interest trigger gene expression. The expression stops if we remove the bead-bound DNA as well as transcribed mRNA by hybridization to bead-bound ssDNA. Our method is a simple way to control expression duration very accurately in time and space.
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35
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The Vc2 Cyclic di-GMP-Dependent Riboswitch of Vibrio cholerae Regulates Expression of an Upstream Putative Small RNA by Controlling RNA Stability. J Bacteriol 2019; 201:JB.00293-19. [PMID: 31405916 DOI: 10.1128/jb.00293-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/17/2019] [Indexed: 11/20/2022] Open
Abstract
Cyclic di-GMP (c-di-GMP) is a bacterial second messenger molecule that is important in the biology of Vibrio cholerae, but the molecular mechanisms by which this molecule regulates downstream phenotypes have not been fully characterized. We have previously shown that the Vc2 c-di-GMP-binding riboswitch, encoded upstream of the gene tfoY, functions as an off switch in response to c-di-GMP. However, the mechanism by which c-di-GMP controls expression of tfoY has not been fully elucidated. During our studies of this mechanism, we determined that c-di-GMP binding to Vc2 also controls the abundance and stability of upstream noncoding RNAs with 3' ends located immediately downstream of the Vc2 riboswitch. Our results suggest these putative small RNAs (sRNAs) are not generated by transcriptional termination but rather by preventing degradation of the upstream untranslated RNA when c-di-GMP is bound to Vc2.IMPORTANCE Riboswitches are typically RNA elements located in the 5' untranslated region of mRNAs. They are highly structured and specifically recognize and respond to a given chemical cue to alter transcription termination or translation initiation. In this work, we report a novel mechanism of riboswitch-mediated gene regulation in Vibrio cholerae whereby a 3' riboswitch, named Vc2, controls the stability of upstream untranslated RNA upon binding to its cognate ligand, the second messenger cyclic di-GMP, leading to the accumulation of previously undescribed putative sRNAs. We further demonstrate that binding of the ligand to the riboswitch prevents RNA degradation. As binding of riboswitches to their ligands often produces compactly structured RNA, we hypothesize this mechanism of gene regulation is widespread.
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Abstract
Numerous studies based on new single-cell and single-gene techniques show that individual genes can be transcribed in short bursts or pulses accompanied by changes in pulsing frequencies. Since so many examples of such discontinuous or fluctuating transcription have been found from prokaryotes to mammals, it now seems to be a common mode of gene expression. In this review we discuss the occurrence of the transcriptional fluctuations, the techniques used for their detection, their putative causes, kinetic characteristics, and probable physiological significance.
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Affiliation(s)
- Evgeny Smirnov
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Matúš Hornáček
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Tomáš Vacík
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Dušan Cmarko
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
| | - Ivan Raška
- a Institute of Biology and Medical Genetics , First Faculty of Medicine , Charles University and General University Hospital in Prague , Prague , Czech Republic
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37
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Weiner I, Shahar N, Marco P, Yacoby I, Tuller T. Solving the Riddle of the Evolution of Shine-Dalgarno Based Translation in Chloroplasts. Mol Biol Evol 2019; 36:2854-2860. [DOI: 10.1093/molbev/msz210] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AbstractChloroplasts originated from an ancient cyanobacterium and still harbor a bacterial-like genome. However, the centrality of Shine–Dalgarno ribosome binding, which predominantly regulates proteobacterial translation initiation, is significantly decreased in chloroplasts. As plastid ribosomal RNA anti-Shine–Dalgarno elements are similar to their bacterial counterparts, these sites alone cannot explain this decline. By computational simulation we show that upstream point mutations modulate the local structure of ribosomal RNA in chloroplasts, creating significantly tighter structures around the anti-Shine–Dalgarno locus, which in-turn reduce the probability of ribosome binding. To validate our model, we expressed two reporter genes (mCherry, hydrogenase) harboring a Shine–Dalgarno motif in the Chlamydomonas reinhardtii chloroplast. Coexpressing them with a 16S ribosomal RNA, modified according to our model, significantly enhances mCherry and hydrogenase expression compared with coexpression with an endogenous 16S gene.
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Affiliation(s)
- Iddo Weiner
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Noam Shahar
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Pini Marco
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Iftach Yacoby
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Tamir Tuller
- Department of Biomedical Engineering, The Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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38
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Yus E, Lloréns-Rico V, Martínez S, Gallo C, Eilers H, Blötz C, Stülke J, Lluch-Senar M, Serrano L. Determination of the Gene Regulatory Network of a Genome-Reduced Bacterium Highlights Alternative Regulation Independent of Transcription Factors. Cell Syst 2019; 9:143-158.e13. [PMID: 31445891 PMCID: PMC6721554 DOI: 10.1016/j.cels.2019.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 04/14/2019] [Accepted: 06/27/2019] [Indexed: 11/30/2022]
Abstract
Here, we determined the relative importance of different transcriptional mechanisms in the genome-reduced bacterium Mycoplasma pneumoniae, by employing an array of experimental techniques under multiple genetic and environmental perturbations. Of the 143 genes tested (21% of the bacterium’s annotated proteins), only 55% showed an altered phenotype, highlighting the robustness of biological systems. We identified nine transcription factors (TFs) and their targets, representing 43% of the genome, and 16 regulators that indirectly affect transcription. Only 20% of transcriptional regulation is mediated by canonical TFs when responding to perturbations. Using a Random Forest, we quantified the non-redundant contribution of different mechanisms such as supercoiling, metabolic control, RNA degradation, and chromosome topology to transcriptional changes. Model-predicted gene changes correlate well with experimental data in 95% of the tested perturbations, explaining up to 70% of the total variance when also considering noise. This analysis highlights the importance of considering non-TF-mediated regulation when engineering bacteria. Full comprehensive reconstruction of a bacterial gene regulatory network achieved Genome-reduced bacterium Mycoplasma pneumoniae is robust to genetic perturbations Large part of transcription regulation in bacteria is transcription-factor independent Transcription-factor-independent regulation has a smaller dynamic range
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Affiliation(s)
- Eva Yus
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain.
| | - Verónica Lloréns-Rico
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain.
| | - Sira Martínez
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain
| | - Carolina Gallo
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain
| | - Hinnerk Eilers
- Department for General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Cedric Blötz
- Department for General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Jörg Stülke
- Department for General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Maria Lluch-Senar
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain
| | - Luis Serrano
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluis Companys 23, Barcelona 08010, Spain.
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39
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Steiner PA, De Corte D, Geijo J, Mena C, Yokokawa T, Rattei T, Herndl GJ, Sintes E. Highly variable mRNA half-life time within marine bacterial taxa and functional genes. Environ Microbiol 2019; 21:3873-3884. [PMID: 31298776 PMCID: PMC7379614 DOI: 10.1111/1462-2920.14737] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 07/08/2019] [Accepted: 07/09/2019] [Indexed: 02/04/2023]
Abstract
Messenger RNA can provide valuable insights into the variability of metabolic processes of microorganisms. However, due to uncertainties that include the stability of RNA, its application for activity profiling of environmental samples is questionable. We explored different factors affecting the decay rate of transcripts of three marine bacterial isolates using qPCR and determined mRNA half‐life time of specific bacterial taxa and of functional genes by metatranscriptomics of a coastal environmental prokaryotic community. The half‐life time of transcripts from 11 genes from bacterial isolates ranged from 1 to 46 min. About 80% of the analysed transcripts exhibited half‐live times shorter than 10 min. Significant differences were found in the half‐life time between mRNA and rRNA. The half‐life time of mRNA obtained from a coastal metatranscriptome ranged from 9 to 400 min. The shortest half‐life times of the metatranscriptome corresponded to transcripts from the same clusters of orthologous groups (COGs) in all bacterial classes. The prevalence of short mRNA half‐life time in genes related to defence mechanisms and motility indicate a tight connection of RNA decay rate to environmental stressors. The short half‐life time of RNA and its high variability needs to be considered when assessing metatranscriptomes especially in environmental samples.
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Affiliation(s)
- Paul A Steiner
- Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Daniele De Corte
- Marine Functional Biology Group, Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natushima 2-15, Yokosuka, Kanagawa, Japan
| | - Javier Geijo
- Department of Microbiology and Ecosystem Science, Division of Computational Systems Biology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Catalina Mena
- Instituto Español de Oceanografia, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015, Palma, Spain
| | - Taichi Yokokawa
- Institute for Extra-cutting-edge Science and Technology Avant-garde Research (X-star), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natushima 2-15, Yokosuka, Kanagawa, Japan
| | - Thomas Rattei
- Department of Microbiology and Ecosystem Science, Division of Computational Systems Biology, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Gerhard J Herndl
- Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.,Department of Marine Microbiology and Biogeochemistry, Royal Netherlands Institute for Sea Research, Utrecht University, PO Box 59, Alberta Den Burg, 1790, The Netherlands
| | - Eva Sintes
- Limnology and Bio-Oceanography, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria.,Instituto Español de Oceanografia, Centre Oceanogràfic de les Balears, Moll de Ponent s/n, 07015, Palma, Spain
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40
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Gilles-Gonzalez MA, Sousa EHS. Escherichia coli DosC and DosP: a role of c-di-GMP in compartmentalized sensing by degradosomes. Adv Microb Physiol 2019; 75:53-67. [PMID: 31655742 DOI: 10.1016/bs.ampbs.2019.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Escherichia coli operon dosCP, also called yddV-yddU, co-expresses two heme proteins, DosC and DosP, both of which are direct oxygen sensors but paradoxically have opposite effects on the levels of the second messenger c-di-GMP. DosC is a diguanylate cyclase that synthesizes c-di-GMP from GTP, whereas DosP is a phosphodiesterase that linearizes c-di-GMP to pGpG. Both proteins are associated with the large degradosome enzyme complex that regulates many bacterial genes post-transcriptionally by processing or degrading the corresponding RNAs. Moreover, the c-di-GMP directly binds to PNPase, a key degradosome enzyme, and enhances its activity. This review combines biochemical, biophysical, and genetic findings on DosC and DosP, a task that has not been undertaken until now, partly because of the varied nomenclature. The DosC and DosP system is examined in the context of the current knowledge of degradosomes and considered as a possible prototype for the compartmentalization of sensing by E. coli.
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Affiliation(s)
| | - Eduardo H S Sousa
- Department of Organic and Inorganic Chemistry, Federal University of Ceara, Center for Sciences, Fortaleza, Ceara, Brazil
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41
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Haines MC, Storch M, Oyarzún DA, Stan GB, Baldwin GS. Riboswitch identification using Ligase-Assisted Selection for the Enrichment of Responsive Ribozymes (LigASERR). Synth Biol (Oxf) 2019; 4:ysz019. [PMID: 32995542 PMCID: PMC7445825 DOI: 10.1093/synbio/ysz019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/17/2019] [Accepted: 06/18/2019] [Indexed: 12/22/2022] Open
Abstract
In vitro selection of ligand-responsive ribozymes can identify rare, functional sequences from large libraries. While powerful, key caveats of this approach include lengthy and demanding experimental workflows; unpredictable experimental outcomes and unknown functionality of enriched sequences in vivo. To address the first of these limitations, we developed Ligase-Assisted Selection for the Enrichment of Responsive Ribozymes (LigASERR). LigASERR is scalable, amenable to automation and requires less time to implement compared to alternative methods. To improve the predictability of experiments, we modeled the underlying selection process, predicting experimental outcomes based on sequence and population parameters. We applied this new methodology and model to the enrichment of a known, in vitro-selected sequence from a bespoke library. Prior to implementing selection, conditions were optimized and target sequence dynamics accurately predicted for the majority of the experiment. In addition to enriching the target sequence, we identified two new, theophylline-activated ribozymes. Notably, all three sequences yielded riboswitches functional in Escherichia coli, suggesting LigASERR and similar in vitro selection methods can be utilized for generating functional riboswitches in this organism.
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Affiliation(s)
- Matthew C Haines
- Department of Life Sciences, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, UK
| | - Marko Storch
- Department of Life Sciences, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, UK.,London BioFoundry, Imperial College Translation & Innovation Hub, London, UK
| | - Diego A Oyarzún
- School of Informatics, University of Edinburgh, Edinburgh, UK.,School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Guy-Bart Stan
- Imperial College Centre for Synthetic Biology, Imperial College London, London, UK.,Department of Bioengineering, Imperial College London, London, UK
| | - Geoff S Baldwin
- Department of Life Sciences, Imperial College London, London, UK.,Imperial College Centre for Synthetic Biology, Imperial College London, London, UK
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42
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Aprianto R, Slager J, Holsappel S, Veening JW. High-resolution analysis of the pneumococcal transcriptome under a wide range of infection-relevant conditions. Nucleic Acids Res 2019; 46:9990-10006. [PMID: 30165663 PMCID: PMC6212715 DOI: 10.1093/nar/gky750] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/09/2018] [Indexed: 12/18/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic human pathogen that typically colonizes the nasopharyngeal passage and causes lethal disease in other host niches, such as the lung or the meninges. The expression and regulation of pneumococcal genes at different life-cycle stages, such as commensal or pathogenic, are not entirely understood. To chart the transcriptional responses of S. pneumoniae, we used RNA-seq to quantify the relative abundance of the transcriptome under 22 different infection-relevant conditions. The data demonstrated a high level of dynamic expression and, strikingly, all annotated pneumococcal genomic features were expressed in at least one of the studied conditions. By computing the correlation values of every pair of genes across all studied conditions, we created a co-expression matrix that provides valuable information on both operon structure and regulatory processes. The co-expression data are highly consistent with well-characterized operons and regulons, such as the PyrR, ComE and ComX regulons, and have allowed us to identify a new member of the competence regulon. Lastly, we created an interactive data center named PneumoExpress (https://veeninglab.com/pneumoexpress) that enables users to access the expression data as well as the co-expression matrix in an intuitive and efficient manner, providing a valuable resource to the pneumococcal research community.
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Affiliation(s)
- Rieza Aprianto
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jelle Slager
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Siger Holsappel
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.,Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, CH-1015 Lausanne, Switzerland
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43
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El-Rami F, Kong X, Parikh H, Zhu B, Stone V, Kitten T, Xu P. Analysis of essential gene dynamics under antibiotic stress in Streptococcus sanguinis. MICROBIOLOGY-SGM 2019; 164:173-185. [PMID: 29393020 PMCID: PMC5882076 DOI: 10.1099/mic.0.000595] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The paradoxical response of Streptococcus sanguinis to drugs prescribed for dental and clinical practices has complicated treatment guidelines and raised the need for further investigation. We conducted a high throughput study on concomitant transcriptome and proteome dynamics in a time course to assess S. sanguinis behaviour under a sub-inhibitory concentration of ampicillin. Temporal changes at the transcriptome and proteome level were monitored to cover essential genes and proteins over a physiological map of intricate pathways. Our findings revealed that translation was the functional category in S. sanguinis that was most enriched in essential proteins. Moreover, essential proteins in this category demonstrated the greatest conservation across 2774 bacterial proteomes, in comparison to other essential functional categories like cell wall biosynthesis and energy production. In comparison to non-essential proteins, essential proteins were less likely to contain ‘degradation-prone’ amino acids at their N-terminal position, suggesting a longer half-life. Despite the ampicillin-induced stress, the transcriptional up-regulation of amino acid-tRNA synthetases and proteomic elevation of amino acid biosynthesis enzymes favoured the enriched components of essential proteins revealing ‘proteomic signatures’ that can be used to bridge the genotype–phenotype gap of S. sanguinis under ampicillin stress. Furthermore, we identified a significant correlation between the levels of mRNA and protein for essential genes and detected essential protein-enriched pathways differentially regulated through a persistent stress response pattern at late time points. We propose that the current findings will help characterize a bacterial model to study the dynamics of essential genes and proteins under clinically relevant stress conditions.
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Affiliation(s)
- Fadi El-Rami
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - Xiangzhen Kong
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA
| | - Hardik Parikh
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - Bin Zhu
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA
| | - Victoria Stone
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - Ping Xu
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA.,Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, VA, USA
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44
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Kim S, Jacobs-Wagner C. Effects of mRNA Degradation and Site-Specific Transcriptional Pausing on Protein Expression Noise. Biophys J 2019; 114:1718-1729. [PMID: 29642040 DOI: 10.1016/j.bpj.2018.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/30/2018] [Accepted: 02/07/2018] [Indexed: 12/20/2022] Open
Abstract
Genetically identical cells exhibit diverse phenotypes even when experiencing the same environment. This phenomenon in part originates from cell-to-cell variability (noise) in protein expression. Although various kinetic schemes of stochastic transcription initiation are known to affect gene expression noise, how posttranscription initiation events contribute to noise at the protein level remains incompletely understood. To address this question, we developed a stochastic simulation-based model of bacterial gene expression that integrates well-known dependencies between transcription initiation, transcription elongation dynamics, mRNA degradation, and translation. We identified realistic conditions under which mRNA lifetime and transcriptional pauses modulate the protein expression noise initially introduced by the promoter architecture. For instance, we found that the short lifetime of bacterial mRNAs facilitates the production of protein bursts. Conversely, RNA polymerase (RNAP) pausing at specific sites during transcription elongation can attenuate protein bursts by fluidizing the RNAP traffic to the point of erasing the effect of a bursty promoter. Pause-prone sites, if located close to the promoter, can also affect noise indirectly by reducing both transcription and translation initiation due to RNAP and ribosome congestion. Our findings highlight how the interplay between transcription initiation, transcription elongation, translation, and mRNA degradation shapes the distribution in protein numbers. They also have implications for our understanding of gene evolution and suggest combinatorial strategies for modulating phenotypic variability by genetic engineering.
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Affiliation(s)
- Sangjin Kim
- Microbial Sciences Institute, West Haven, Connecticut; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut; Howard Hughes Medical Institute, New Haven, Connecticut
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, West Haven, Connecticut; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut; Howard Hughes Medical Institute, New Haven, Connecticut; Department of Microbial Pathogenesis, Yale School of Medicine, Yale University, New Haven, Connecticut.
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45
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Scholz SA, Diao R, Wolfe MB, Fivenson EM, Lin XN, Freddolino PL. High-Resolution Mapping of the Escherichia coli Chromosome Reveals Positions of High and Low Transcription. Cell Syst 2019; 8:212-225.e9. [PMID: 30904377 DOI: 10.1016/j.cels.2019.02.004] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/19/2018] [Accepted: 02/11/2019] [Indexed: 01/28/2023]
Abstract
Recent studies on targeted gene integrations in bacteria have demonstrated that chromosomal location can substantially affect a gene's expression level. However, these studies have only provided information on a small number of sites. To measure position effects on transcriptional propensity at high resolution across the genome, we built and analyzed a library of over 144,000 genome-integrated, standardized reporters in a single mixed population of Escherichia coli. We observed more than 20-fold variations in transcriptional propensity across the genome when the length of the chromosome was binned into broad 4 kbp regions; greater variability was observed over smaller regions. Our data reveal peaks of high transcriptional propensity centered on ribosomal RNA operons and core metabolic genes, while prophages and mobile genetic elements were enriched in less transcribable regions. In total, our work supports the hypothesis that E. coli has evolved gene-independent mechanisms for regulating expression from specific regions of its genome.
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Affiliation(s)
- Scott A Scholz
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI 48103, USA
| | - Rucheng Diao
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48103, USA
| | - Michael B Wolfe
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48103, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48103, USA
| | - Elayne M Fivenson
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48103, USA
| | - Xiaoxia Nina Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48103, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48103, USA.
| | - Peter L Freddolino
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48103, USA; Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48103, USA.
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46
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Mohanty BK, Kushner SR. Analysis of post-transcriptional RNA metabolism in prokaryotes. Methods 2019; 155:124-130. [PMID: 30448478 PMCID: PMC6568318 DOI: 10.1016/j.ymeth.2018.11.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/08/2018] [Accepted: 11/13/2018] [Indexed: 02/08/2023] Open
Abstract
Post-transcriptional RNA metabolic pathways play important roles in permitting prokaryotes to operate under a variety of environmental conditions. Although significant progress has been made during the last decade in deciphering RNA processing pathways in a number of bacteria, a complete understanding of post-transcriptional RNA metabolism in any single microorganism is far from reality. Here we describe multiple experimental approaches that can be used to study mRNA stability, tRNA and rRNA processing, sRNA metabolism, and polyadenylation in prokaryotes. The methods described here can be readily utilized in both Gram-negative and Gram-positive bacteria with simple modifications.
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MESH Headings
- Base Sequence
- Blotting, Northern
- Cloning, Molecular
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- Denaturing Gradient Gel Electrophoresis
- Deoxyribonuclease I/chemistry
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Half-Life
- Polyadenylation
- RNA Processing, Post-Transcriptional
- RNA Stability
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Sequence Analysis, DNA/methods
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Affiliation(s)
- Bijoy K. Mohanty
- Department of Genetics, University of Georgia, Athens, Georgia 30602, Tel. No. 706-542-8000,
| | - Sidney R. Kushner
- Department of Genetics, University of Georgia, Athens, Georgia 30602, Tel. No. 706-542-8000,
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47
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Cholet F, Ijaz UZ, Smith CJ. Differential ratio amplicons (R amp ) for the evaluation of RNA integrity extracted from complex environmental samples. Environ Microbiol 2019; 21:827-844. [PMID: 30585386 PMCID: PMC6392129 DOI: 10.1111/1462-2920.14516] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/07/2018] [Accepted: 12/20/2018] [Indexed: 12/31/2022]
Abstract
Reliability and reproducibility of transcriptomics‐based studies are dependent on RNA integrity. In microbial ecology, microfluidics‐based techniques, such as the Ribosomal Integrity Number (RIN), targeting rRNA are currently the only approaches to evaluate RNA integrity. However, the relationship between rRNA and mRNA integrity is unknown. Here, we present an integrity index, the Ratio Amplicon, Ramp, adapted from human clinical studies, to directly monitor mRNA integrity from complex environmental samples. We show, in a suite of experimental degradations of RNA extracted from sediment, that while the RIN generally reflected the degradation status of RNA the Ramp mapped mRNA degradation better. Furthermore, we examined the effect of degradation on transcript community structure by amplicon sequencing of 16S rRNA, amoA and glnA transcripts. We successfully sequenced transcripts for all three targets even from highly‐degraded RNA samples. While RNA degradation changed the community structure of the mRNA profiles, no changes were observed for the 16S rRNA transcript profiles. Since both RT‐Q‐PCR and sequencing results were obtained, even from highly degraded samples, we strongly recommend evaluating RNA integrity prior to downstream processing to ensure meaningful results. For this, both the RIN and Ramp are useful, with the Ramp better evaluating mRNA integrity in this study.
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Affiliation(s)
- Fabien Cholet
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
| | - Umer Z Ijaz
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
| | - Cindy J Smith
- Infrastructure and Environment Research Division, School of Engineering, University of Glasgow, Glasgow, G12 8LT, UK
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Gordon GC, Pfleger BF. Regulatory Tools for Controlling Gene Expression in Cyanobacteria. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1080:281-315. [PMID: 30091100 PMCID: PMC6662922 DOI: 10.1007/978-981-13-0854-3_12] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cyanobacteria are attractive hosts for converting carbon dioxide and sunlight into desirable chemical products. To engineer these organisms and manipulate their metabolic pathways, the biotechnology community has developed genetic tools to control gene expression. Many native cyanobacterial promoters and related sequence elements have been used to regulate genes of interest, and heterologous tools that use non-native small molecules to induce gene expression have been demonstrated. Overall, IPTG-based induction systems seem to be leaky and initially demonstrate small dynamic ranges in cyanobacteria. Consequently, a variety of other induction systems have been optimized to enable tighter control of gene expression. Tools require significant optimization because they function quite differently in cyanobacteria when compared to analogous use in model heterotrophs. We hypothesize that these differences are due to fundamental differences in physiology between organisms. This review is not intended to summarize all known products made in cyanobacteria nor the performance (titer, rate, yield) of individual strains, but instead will focus on the genetic tools and the inherent aspects of cellular physiology that influence gene expression in cyanobacteria.
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Affiliation(s)
- Gina C Gordon
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, USA.
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA.
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Component Characterization in a Growth-Dependent Physiological Context: Optimal Experimental Design. Processes (Basel) 2019. [DOI: 10.3390/pr7010052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Synthetic biology design challenges have driven the use of mathematical models to characterize genetic components and to explore complex design spaces. Traditional approaches to characterization have largely ignored the effect of strain and growth conditions on the dynamics of synthetic genetic circuits, and have thus confounded intrinsic features of the circuit components with cell-level context effects. We present a model that distinguishes an activated gene’s intrinsic kinetics from its physiological context. We then demonstrate an optimal experimental design approach to identify dynamic induction experiments for efficient estimation of the component’s intrinsic parameters. Maximally informative experiments are chosen by formulating the design as an optimal control problem; direct multiple-shooting is used to identify the optimum. Our numerical results suggest that the intrinsic parameters of a genetic component can be more accurately estimated using optimal experimental designs, and that the choice of growth rates, sampling schedule, and input profile each play an important role. The proposed approach to coupled component–host modelling can support gene circuit design across a range of physiological conditions.
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Adibzadeh S, Fardaei M, Takhshid MA, Miri MR, Rafiei Dehbidi G, Farhadi A, Ranjbaran R, Alavi P, Nikouyan N, Seyyedi N, Naderi S, Eskandari A, Behzad-Behbahani A. Enhancing Stability of Destabilized Green Fluorescent Protein Using Chimeric mRNA Containing Human Beta-Globin 5' and 3' Untranslated Regions. Avicenna J Med Biotechnol 2019; 11:112-117. [PMID: 30800251 PMCID: PMC6359690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND In spite of recent progress in mRNA technologies and their potential applications for treatment of human diseases, problems such as the transient nature of mRNA limit the stability of gene up-regulation and, thus, potentially reduce mRNA efficiency for gene therapy. Using human β-globin 5' and 3' untranslated regions (UTRs), this study aimed to develop the different chimeric constructs of mRNAs to increase the stability of destabilized green fluorescent protein (EGFPd2) in HEK 293 cells. METHODS Purified human β-globin (HBG) 5'-3'UTRs, and the coding sequence of destabilized green fluorescent protein (EGFPd2) were amplified separately and ligated to each other using SOEing PCR method in a different format. As controls, the original construct of EGFPd2 under the control of T7 promoter was used. Following in vitro transcription, HEK 293 cells were then transfected with several constructs and incubated at 37°C in a CO2 incubator. They were monitored under a fluorescence microscope every four hours for the first 24 hr, then every 12 hr afterwards. The resulting fluorescence was measured as a surrogate for translation efficiency and duration. RESULTS By monitoring the HEK cells over 48 hr, cells transfected with mRNA with various HBG UTRs showed significantly different fluorescence intensity and stability in comparison with the pEGFPd2 prototype (control transcript) overtime. Overall, the images show that replacement of the 3' UTR end of the prototype vector pGFPd2 with the 3' end of β-globin mRNA increases the half-life of the chimeric mRNA for more than 32 hr. CONCLUSION This result indicates that β-globin 3' UTR would definitely increase the half-life of mRNA and may help to decrease the mRNA therapeutic dosage in the treatment of diseases associated with mRNA therapy.
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Affiliation(s)
- Setare Adibzadeh
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran, Department of Medical Biotechnology, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Majid Fardaei
- Department of Genetics, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Ali Takhshid
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Reza Miri
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Gholamreza Rafiei Dehbidi
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ali Farhadi
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Reza Ranjbaran
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Parnian Alavi
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Negin Nikouyan
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Noorossadat Seyyedi
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Samaneh Naderi
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Alireaz Eskandari
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Abbas Behzad-Behbahani
- Diagnostic Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran,Corresponding author: Abbas Behzad-Behbahani, Ph.D., Diagnosis Laboratory Sciences and Technology Research Center, Faculty of Paramedical Sciences, Shiraz University of Medical Sciences, Shiraz, Iran, Tel: +98 71 32270301, Fax: +98 71 32270301, E-mail:,
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