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Jones EM, Marken JP, Silver PA. Synthetic microbiology in sustainability applications. Nat Rev Microbiol 2024; 22:345-359. [PMID: 38253793 DOI: 10.1038/s41579-023-01007-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2023] [Indexed: 01/24/2024]
Abstract
Microorganisms are a promising means to address many societal sustainability challenges owing to their ability to thrive in diverse environments and interface with the microscale chemical world via diverse metabolic capacities. Synthetic biology can engineer microorganisms by rewiring their regulatory networks or introducing new functionalities, enhancing their utility for target applications. In this Review, we provide a broad, high-level overview of various research efforts addressing sustainability challenges through synthetic biology, emphasizing foundational microbiological research questions that can accelerate the development of these efforts. We introduce an organizational framework that categorizes these efforts along three domains - factory, farm and field - that are defined by the extent to which the engineered microorganisms interface with the natural external environment. Different application areas within the same domain share many fundamental challenges, highlighting productive opportunities for cross-disciplinary collaborations between researchers working in historically disparate fields.
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Affiliation(s)
- Ethan M Jones
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - John P Marken
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Resnick Sustainability Institute, California Institute of Technology, Pasadena, CA, USA
| | - Pamela A Silver
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA.
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
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2
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Smith EL, Panis G, Woldemeskel SA, Viollier PH, Chien P, Goley ED. Regulation of the transcription factor CdnL promotes adaptation to nutrient stress in Caulobacter. PNAS NEXUS 2024; 3:pgae154. [PMID: 38650860 PMCID: PMC11034885 DOI: 10.1093/pnasnexus/pgae154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024]
Abstract
In response to nutrient deprivation, bacteria activate a conserved stress response pathway called the stringent response (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes the secondary messengers guanosine 5'-diphosphate 3'-diphosphate and guanosine 5'-triphosphate 3'-diphosphate (collectively known as (p)ppGpp), which affect transcription by binding RNA polymerase (RNAP) to down-regulate anabolic genes. (p)ppGpp also impacts the expression of anabolic genes by controlling the levels and activities of their transcriptional regulators. In Caulobacter, a major regulator of anabolic genes is the transcription factor CdnL. If and how CdnL is controlled during the SR and why that might be functionally important are unclear. In this study, we show that CdnL is down-regulated posttranslationally during starvation in a manner dependent on SpoT and the ClpXP protease. Artificial stabilization of CdnL during starvation causes misregulation of ribosomal and metabolic genes. Functionally, we demonstrate that the combined action of SR transcriptional regulators and CdnL clearance allows for rapid adaptation to nutrient repletion. Moreover, cells that are unable to clear CdnL during starvation are outcompeted by wild-type cells when subjected to nutrient fluctuations. We hypothesize that clearance of CdnL during the SR, in conjunction with direct binding of (p)ppGpp and DksA to RNAP, is critical for altering the transcriptome in order to permit cell survival during nutrient stress.
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Affiliation(s)
- Erika L Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gaël Panis
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Patrick H Viollier
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva 1211, Switzerland
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, MA 01003, USA
| | - Erin D Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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3
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Smith EL, Panis G, Woldemeskel SA, Viollier PH, Chien P, Goley ED. Regulation of the transcription factor CdnL promotes adaptation to nutrient stress in Caulobacter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572625. [PMID: 38187569 PMCID: PMC10769358 DOI: 10.1101/2023.12.20.572625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
In response to nutrient deprivation, bacteria activate a conserved stress response pathway called the stringent response (SR). During SR activation in Caulobacter crescentus, SpoT synthesizes the secondary messengers (p)ppGpp, which affect transcription by binding RNA polymerase to downregulate anabolic genes. (p)ppGpp also impacts expression of anabolic genes by controlling the levels and activities of their transcriptional regulators. In Caulobacter, a major regulator of anabolic genes is the transcription factor CdnL. If and how CdnL is controlled during the SR and why that might be functionally important is unclear. Here, we show that CdnL is downregulated post-translationally during starvation in a manner dependent on SpoT and the ClpXP protease. Inappropriate stabilization of CdnL during starvation causes misregulation of ribosomal and metabolic genes. Functionally, we demonstrate that the combined action of SR transcriptional regulators and CdnL clearance allows for rapid adaptation to nutrient repletion. Moreover, cells that are unable to clear CdnL during starvation are outcompeted by wild-type cells when subjected to nutrient fluctuations. We hypothesize that clearance of CdnL during the SR, in conjunction with direct binding of (p)ppGpp and DksA to RNAP, is critical for altering the transcriptome in order to permit cell survival during nutrient stress.
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Affiliation(s)
- Erika L. Smith
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
| | - Gaäl Panis
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland, 1211
| | - Selamawit Abi Woldemeskel
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
- BlueRock Therapeutics, Cambridge, Massachusetts, 02142 (current)
| | - Patrick H. Viollier
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland, 1211
| | - Peter Chien
- Department of Biochemistry and Molecular Biology, University of Massachusetts-Amherst, Amherst, Massachusetts, 01003
| | - Erin D. Goley
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, 21205
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Wang X, Yu S, Lou E, Tan YL, Tan ZJ. RNA 3D Structure Prediction: Progress and Perspective. Molecules 2023; 28:5532. [PMID: 37513407 PMCID: PMC10386116 DOI: 10.3390/molecules28145532] [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: 06/14/2023] [Revised: 07/05/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
Ribonucleic acid (RNA) molecules play vital roles in numerous important biological functions such as catalysis and gene regulation. The functions of RNAs are strongly coupled to their structures or proper structure changes, and RNA structure prediction has been paid much attention in the last two decades. Some computational models have been developed to predict RNA three-dimensional (3D) structures in silico, and these models are generally composed of predicting RNA 3D structure ensemble, evaluating near-native RNAs from the structure ensemble, and refining the identified RNAs. In this review, we will make a comprehensive overview of the recent advances in RNA 3D structure modeling, including structure ensemble prediction, evaluation, and refinement. Finally, we will emphasize some insights and perspectives in modeling RNA 3D structures.
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Affiliation(s)
- Xunxun Wang
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Shixiong Yu
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - En Lou
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Ya-Lan Tan
- School of Bioengineering and Health, Wuhan Textile University, Wuhan 430200, China
- Research Center of Nonlinear Science, School of Mathematical and Physical Sciences, Wuhan Textile University, Wuhan 430200, China
| | - Zhi-Jie Tan
- Department of Physics, Key Laboratory of Artificial Micro & Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, China
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Wang X, Han Q, Yu Q, Wang S, Yang J, Su W, Wan-Yan R, Sun X, Li H. Mammalian carcass decay increases carbon storage and temporal turnover of carbon-fixing microbes in alpine meadow soil. ENVIRONMENTAL RESEARCH 2023; 225:115653. [PMID: 36898422 DOI: 10.1016/j.envres.2023.115653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/20/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Corpse decomposition is of great significance to the carbon cycle of natural ecosystem. Carbon fixation is a carbon conversion process that converts carbon dioxide into organic carbon, which greatly contributes to carbon emission reduction. However, the effects of wild animal carcass decay on carbon-fixing microbes in grassland soil environment are still unknown. In this research, thirty wild mammal (Ochotona curzoniae) corpses were placed on alpine meadow soil to study the carbon storage and carbon-fixing microbiota succession for a 94-day decomposition using next-generation sequencing. Our results revealed that 1) the concentration of total carbon increased approximately 2.24-11.22% in the corpse group. 2) Several carbon-fixing bacterial species (Calothrix parietina, Ancylobacter rudongensis, Rhodopseudomonas palustris) may predict the concentration of total carbon. 3) Animal cadaver degradation caused the differentiation of carbon-fixing microbiota structures during succession and made the medium-stage networks of carbon-fixing microbes more complicated. 4) The temporal turnover rate in the experimental groups was higher than that in the control groups, indicating a quick change of gravesoil carbon-fixing microbiota. 5) The deterministic process dominates the assembly mechanism of experimental groups (ranging from 53.42% to 94.94%), which reflects that the carbon-fixing microbial community in gravesoil can be regulated. Under global climate change, this study provides a new perspective for understanding the effects of wild animal carcass decay on soil carbon storage and carbon-fixing microbes.
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Affiliation(s)
- Xiaochen Wang
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Qian Han
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Qiaoling Yu
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Sijie Wang
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Jiawei Yang
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Wanghong Su
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Ruijun Wan-Yan
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Xiaofang Sun
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China
| | - Huan Li
- Institute of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou, 730000, China; State Key Laboratory of Grassland Agro-ecosystems, Center for Grassland Microbiome, Lanzhou University, Lanzhou, 730000, China.
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Abstract
Since Jacques Monod's foundational work in the 1940s, investigators studying bacterial physiology have largely (but not exclusively) focused on the exponential phase of bacterial cultures, which is characterized by rapid growth and high biosynthesis activity in the presence of excess nutrients. However, this is not the predominant state of bacterial life. In nature, most bacteria experience nutrient limitation most of the time. In fact, investigators even prior to Monod had identified other aspects of bacterial growth, including what is now known as the stationary phase, when nutrients become limiting. This review will discuss how bacteria transition to growth arrest in response to nutrient limitation through changes in transcription, translation, and metabolism. We will then examine how these changes facilitate survival during potentially extended periods of nutrient limitation, with particular attention to the metabolic strategies that underpin bacterial longevity in this state.
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Affiliation(s)
- Jonathan Dworkin
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA;
| | - Caroline S Harwood
- Department of Microbiology, University of Washington, Seattle, Washington, USA;
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7
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Chen C, Ao J, Wang L, Zhang J, Mo Y, Zhang Y, Zhao L. Characterisation of the molecular mechanisms of multiple antibiotic tolerance in growth‐arrested
Cronobacter sakazakii
under ampicillin exposure. Int J Food Sci Technol 2022. [DOI: 10.1111/ijfs.15714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Chuxin Chen
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food Sciences South China Agricultural University Guangzhou Guangdong 510642 China
| | - Jialu Ao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food Sciences South China Agricultural University Guangzhou Guangdong 510642 China
| | - Li Wang
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food Sciences South China Agricultural University Guangzhou Guangdong 510642 China
| | - Jingfeng Zhang
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food Sciences South China Agricultural University Guangzhou Guangdong 510642 China
| | - Yunshao Mo
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food Sciences South China Agricultural University Guangzhou Guangdong 510642 China
| | - Yehui Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture Guangzhou Guangdong 510641 China
| | - Lichao Zhao
- Guangdong Provincial Key Laboratory of Nutraceuticals and Functional Foods College of Food Sciences South China Agricultural University Guangzhou Guangdong 510642 China
- Guangdong Laboratory for Lingnan Modern Agriculture Guangzhou Guangdong 510641 China
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Van den Bergh B, Schramke H, Michiels JE, Kimkes TEP, Radzikowski JL, Schimpf J, Vedelaar SR, Burschel S, Dewachter L, Lončar N, Schmidt A, Meijer T, Fauvart M, Friedrich T, Michiels J, Heinemann M. Mutations in respiratory complex I promote antibiotic persistence through alterations in intracellular acidity and protein synthesis. Nat Commun 2022; 13:546. [PMID: 35087069 PMCID: PMC8795404 DOI: 10.1038/s41467-022-28141-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 01/04/2022] [Indexed: 11/28/2022] Open
Abstract
Antibiotic persistence describes the presence of phenotypic variants within an isogenic bacterial population that are transiently tolerant to antibiotic treatment. Perturbations of metabolic homeostasis can promote antibiotic persistence, but the precise mechanisms are not well understood. Here, we use laboratory evolution, population-wide sequencing and biochemical characterizations to identify mutations in respiratory complex I and discover how they promote persistence in Escherichia coli. We show that persistence-inducing perturbations of metabolic homeostasis are associated with cytoplasmic acidification. Such cytoplasmic acidification is further strengthened by compromised proton pumping in the complex I mutants. While RpoS regulon activation induces persistence in the wild type, the aggravated cytoplasmic acidification in the complex I mutants leads to increased persistence via global shutdown of protein synthesis. Thus, we propose that cytoplasmic acidification, amplified by a compromised complex I, can act as a signaling hub for perturbed metabolic homeostasis in antibiotic persisters.
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Affiliation(s)
- Bram Van den Bergh
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
- Department of Entomology, Cornell University, Ithaca, NY, USA
| | - Hannah Schramke
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Joran Elie Michiels
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
| | - Tom E P Kimkes
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Jakub Leszek Radzikowski
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Johannes Schimpf
- Molecular Bioenergetics, Institute of Biochemistry, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Silke R Vedelaar
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Sabrina Burschel
- Molecular Bioenergetics, Institute of Biochemistry, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Liselot Dewachter
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
| | - Nikola Lončar
- Molecular Enzymology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Tim Meijer
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium
- imec, Leuven, Belgium
| | - Thorsten Friedrich
- Molecular Bioenergetics, Institute of Biochemistry, Albert-Ludwigs-University of Freiburg, Freiburg im Breisgau, Germany
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, Department of Molecular and Microbial Systems, KU Leuven, Leuven, Belgium.
- Center for Microbiology, Flanders Institute for Biotechnology, VIB, Leuven, Belgium.
| | - Matthias Heinemann
- Molecular Systems Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, Groningen, The Netherlands.
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Bergkessel M. Bacterial transcription during growth arrest. Transcription 2021; 12:232-249. [PMID: 34486930 PMCID: PMC8632087 DOI: 10.1080/21541264.2021.1968761] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/03/2021] [Accepted: 08/11/2021] [Indexed: 11/12/2022] Open
Abstract
Bacteria in most natural environments spend substantial periods of time limited for essential nutrients and not actively dividing. While transcriptional activity under these conditions is substantially reduced compared to that occurring during active growth, observations from diverse organisms and experimental approaches have shown that new transcription still occurs and is important for survival. Much of our understanding of transcription regulation has come from measuring transcripts in exponentially growing cells, or from in vitro experiments focused on transcription from highly active promoters by the housekeeping RNA polymerase holoenzyme. The fact that transcription during growth arrest occurs at low levels and is highly heterogeneous has posed challenges for its study. However, new methods of measuring low levels of gene expression activity, even in single cells, offer exciting opportunities for directly investigating transcriptional activity and its regulation during growth arrest. Furthermore, much of the rich structural and biochemical data from decades of work on the bacterial transcriptional machinery is also relevant to growth arrest. In this review, the physiological changes likely affecting transcription during growth arrest are first considered. Next, possible adaptations to help facilitate ongoing transcription during growth arrest are discussed. Finally, new insights from several recently published datasets investigating mRNA transcripts in single bacterial cells at various growth phases will be explored. Keywords: Growth arrest, stationary phase, RNA polymerase, nucleoid condensation, population heterogeneity.
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Kamal SM, Simpson DJ, Wang Z, Gänzle M, Römling U. Horizontal Transmission of Stress Resistance Genes Shape the Ecology of Beta- and Gamma-Proteobacteria. Front Microbiol 2021; 12:696522. [PMID: 34295324 PMCID: PMC8290217 DOI: 10.3389/fmicb.2021.696522] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/07/2021] [Indexed: 01/25/2023] Open
Abstract
The transmissible locus of stress tolerance (tLST) is found mainly in beta- and gamma-Proteobacteria and confers tolerance to elevated temperature, pressure, and chlorine. This genomic island, previously referred to as transmissible locus of protein quality control or locus of heat resistance likely originates from an environmental bacterium thriving in extreme habitats, but has been widely transmitted by lateral gene transfer. Although highly conserved, the gene content on the island is subject to evolution and gene products such as small heat shock proteins are present in several functionally distinct sequence variants. A number of these genes are xenologs of core genome genes with the gene products to widen the substrate spectrum and to be highly (complementary) expressed thus their functionality to become dominant over core genome genes. In this review, we will present current knowledge of the function of core tLST genes and discuss current knowledge on selection and counter-selection processes that favor maintenance of the tLST island, with frequent acquisition of gene products involved in cyclic di-GMP signaling, in different habitats from the environment to animals and plants, processed animal and plant products, man-made environments, and subsequently humans.
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Affiliation(s)
- Shady Mansour Kamal
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - David J Simpson
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Zhiying Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
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11
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Bergkessel M, Delavaine L. Diversity in Starvation Survival Strategies and Outcomes among Heterotrophic Proteobacteria. Microb Physiol 2021; 31:146-162. [PMID: 34058747 DOI: 10.1159/000516215] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/28/2021] [Indexed: 11/19/2022]
Abstract
Heterotrophic Proteobacteria are versatile opportunists that have been extensively studied as model organisms in the laboratory, as both pathogens and beneficial symbionts of plants and animals, and as ubiquitous organisms found free-living in many environments. Succeeding in these niches requires an ability to persist for potentially long periods of time in growth-arrested states when essential nutrients become limiting. The tendency of these bacteria to grow in dense biofilm communities frequently leads to the development of steep nutrient gradients and deprivation of interior cells even when the environment is nutrient rich. Surviving within host environments also likely requires tolerating growth arrest due to the host limiting access to nutrients and transitioning between hosts may require a period of survival in a nutrient-poor environment. Interventions to maximise plant-beneficial activities and minimise infections by bacteria will require a better understanding of metabolic and regulatory networks that contribute to starvation survival, and how these networks function in diverse organisms. Here we focus on carbon starvation as a growth-arresting condition that limits availability not only of substrates for biosynthesis but also of energy for ongoing maintenance of the electrochemical gradient across the cell envelope and cellular integrity. We first review models for studying bacterial starvation and known strategies that contribute to starvation survival. We then present the results of a survey of carbon starvation survival strategies and outcomes in ten bacterial strains, including representatives from the orders Enterobacterales and Pseudomonadales (both Gammaproteobacteria) and Burkholderiales (Betaproteobacteria). Finally, we examine differences in gene content between the highest and lowest survivors to identify metabolic and regulatory adaptations that may contribute to differences in starvation survival.
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Affiliation(s)
- Megan Bergkessel
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Laurent Delavaine
- Division of Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee, United Kingdom
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12
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Theng S, Williamson KS, Franklin MJ. Role of Hibernation Promoting Factor in Ribosomal Protein Stability during Pseudomonas aeruginosa Dormancy. Int J Mol Sci 2020; 21:E9494. [PMID: 33327444 PMCID: PMC7764885 DOI: 10.3390/ijms21249494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 01/02/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes biofilm-associated infections. P. aeruginosa can survive in a dormant state with reduced metabolic activity in nutrient-limited environments, including the interiors of biofilms. When entering dormancy, the bacteria undergo metabolic remodeling, which includes reduced translation and degradation of cellular proteins. However, a supply of essential macromolecules, such as ribosomes, are protected from degradation during dormancy. The small ribosome-binding proteins, hibernation promoting factor (HPF) and ribosome modulation factor (RMF), inhibit translation by inducing formation of inactive 70S and 100S ribosome monomers and dimers. The inactivated ribosomes are protected from the initial steps in ribosome degradation, including endonuclease cleavage of the ribosomal RNA (rRNA). Here, we characterized the role of HPF in ribosomal protein (rProtein) stability and degradation during P. aeruginosa nutrient limitation. We determined the effect of the physiological status of P. aeruginosa prior to starvation on its ability to recover from starvation, and on its rRNA and rProtein stability during cell starvation. The results show that the wild-type strain and a stringent response mutant (∆relA∆spoT strain) maintain high cellular abundances of the rProteins L5 and S13 over the course of eight days of starvation. In contrast, the abundances of L5 and S13 reduce in the ∆hpf mutant cells. The loss of rProteins in the ∆hpf strain is dependent on the physiology of the cells prior to starvation. The greatest rProtein loss occurs when cells are first cultured to stationary phase prior to starvation, with less rProtein loss in the ∆hpf cells that are first cultured to exponential phase or in balanced minimal medium. Regardless of the pre-growth conditions, P. aeruginosa recovery from starvation and the integrity of its rRNA are impaired in the absence of HPF. The results indicate that protein remodeling during P. aeruginosa starvation includes the degradation of rProteins, and that HPF is essential to prevent rProtein loss in starved P. aeruginosa. The results also indicate that HPF is produced throughout cell growth, and that regardless of the cellular physiological status, HPF is required to protect against ribosome loss when the cells subsequently enter starvation phase.
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Affiliation(s)
- Sokuntheary Theng
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; (S.T.); (K.S.W.)
| | - Kerry S. Williamson
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; (S.T.); (K.S.W.)
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
| | - Michael J. Franklin
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; (S.T.); (K.S.W.)
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
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