1
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Wang XT, Ma BG. Spatial Chromosome Organization and Adaptation of Escherichia coli under Heat Stress. Microorganisms 2024; 12:1229. [PMID: 38930611 DOI: 10.3390/microorganisms12061229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/14/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024] Open
Abstract
The spatial organization of bacterial chromosomes is crucial for cellular functions. It remains unclear how bacterial chromosomes adapt to high-temperature stress. This study delves into the 3D genome architecture and transcriptomic responses of Escherichia coli under heat-stress conditions to unravel the intricate interplay between the chromosome structure and environmental cues. By examining the role of macrodomains, chromosome interaction domains (CIDs), and nucleoid-associated proteins (NAPs), this work unveils the dynamic changes in chromosome conformation and gene expression patterns induced by high-temperature stress. It was observed that, under heat stress, the short-range interaction frequency of the chromosomes decreased, while the long-range interaction frequency of the Ter macrodomain increased. Furthermore, two metrics, namely, Global Compactness (GC) and Local Compactness (LC), were devised to measure and compare the compactness of the chromosomes based on their 3D structure models. The findings in this work shed light on the molecular mechanisms underlying thermal adaptation and chromosomal organization in bacterial cells, offering valuable insights into the complex inter-relationships between environmental stimuli and genomic responses.
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Affiliation(s)
- Xu-Ting Wang
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Bin-Guang Ma
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
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2
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Gucwa K, Wons E, Wisniewska A, Jakalski M, Dubiak Z, Kozlowski LP, Mruk I. Lethal perturbation of an Escherichia coli regulatory network is triggered by a restriction-modification system's regulator and can be mitigated by excision of the cryptic prophage Rac. Nucleic Acids Res 2024; 52:2942-2960. [PMID: 38153127 PMCID: PMC11014345 DOI: 10.1093/nar/gkad1234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 12/29/2023] Open
Abstract
Bacterial gene regulatory networks orchestrate responses to environmental challenges. Horizontal gene transfer can bring in genes with regulatory potential, such as new transcription factors (TFs), and this can disrupt existing networks. Serious regulatory perturbations may even result in cell death. Here, we show the impact on Escherichia coli of importing a promiscuous TF that has adventitious transcriptional effects within the cryptic Rac prophage. A cascade of regulatory network perturbations occurred on a global level. The TF, a C regulatory protein, normally controls a Type II restriction-modification system, but in E. coli K-12 interferes with expression of the RacR repressor gene, resulting in de-repression of the normally-silent Rac ydaT gene. YdaT is a prophage-encoded TF with pleiotropic effects on E. coli physiology. In turn, YdaT alters expression of a variety of bacterial regulons normally controlled by the RcsA TF, resulting in deficient lipopolysaccharide biosynthesis and cell division. At the same time, insufficient RacR repressor results in Rac DNA excision, halting Rac gene expression due to loss of the replication-defective Rac prophage. Overall, Rac induction appears to counteract the lethal toxicity of YdaT. We show here that E. coli rewires its regulatory network, so as to minimize the adverse regulatory effects of the imported C TF. This complex set of interactions may reflect the ability of bacteria to protect themselves by having robust mechanisms to maintain their regulatory networks, and/or suggest that regulatory C proteins from mobile operons are under selection to manipulate their host's regulatory networks for their own benefit.
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Affiliation(s)
- Katarzyna Gucwa
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Ewa Wons
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Aleksandra Wisniewska
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Marcin Jakalski
- 3P-Medicine Laboratory, Medical University of Gdansk, Debinki 7, 80-211 Gdansk, Poland
| | - Zuzanna Dubiak
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Lukasz Pawel Kozlowski
- Institute of Informatics, Faculty of Mathematics, Informatics and Mechanics, University of Warsaw, Banacha 2, 02-097 Warsaw, Poland
| | - Iwona Mruk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
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3
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Choe D, Olson CA, Szubin R, Yang H, Sung J, Feist AM, Palsson BO. Advancing the scale of synthetic biology via cross-species transfer of cellular functions enabled by iModulon engraftment. Nat Commun 2024; 15:2356. [PMID: 38490991 PMCID: PMC10943186 DOI: 10.1038/s41467-024-46486-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 02/29/2024] [Indexed: 03/18/2024] Open
Abstract
Machine learning applied to large compendia of transcriptomic data has enabled the decomposition of bacterial transcriptomes to identify independently modulated sets of genes, such iModulons represent specific cellular functions. The identification of iModulons enables accurate identification of genes necessary and sufficient for cross-species transfer of cellular functions. We demonstrate cross-species transfer of: 1) the biotransformation of vanillate to protocatechuate, 2) a malonate catabolic pathway, 3) a catabolic pathway for 2,3-butanediol, and 4) an antimicrobial resistance to ampicillin found in multiple Pseudomonas species to Escherichia coli. iModulon-based engineering is a transformative strategy as it includes all genes comprising the transferred cellular function, including genes without functional annotation. Adaptive laboratory evolution was deployed to optimize the cellular function transferred, revealing mutations in the host. Combining big data analytics and laboratory evolution thus enhances the level of understanding of systems biology, and synthetic biology for strain design and development.
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Affiliation(s)
- Donghui Choe
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Connor A Olson
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Richard Szubin
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Hannah Yang
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Jaemin Sung
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Adam M Feist
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Copenhagen, Denmark
| | - Bernhard O Palsson
- Department of Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA.
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Copenhagen, Denmark.
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4
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Verma T, Nandini SS, Singh V, Raghavan A, Annappa H, Bhaskarla C, Dubey AK, Nandi D. Divergent Roles of Escherichia Coli Encoded Lon Protease in Imparting Resistance to Uncouplers of Oxidative Phosphorylation: Roles of marA, rob, soxS and acrB. Curr Microbiol 2024; 81:98. [PMID: 38372817 DOI: 10.1007/s00284-024-03632-w] [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: 09/19/2023] [Accepted: 02/01/2024] [Indexed: 02/20/2024]
Abstract
Uncouplers of oxidative phosphorylation dissipate the proton gradient, causing lower ATP production. Bacteria encounter several non-classical uncouplers in the environment, leading to stress-induced adaptations. Here, we addressed the molecular mechanisms responsible for the effects of uncouplers in Escherichia coli. The expression and functions of genes involved in phenotypic antibiotic resistance were studied using three compounds: two strong uncouplers, i.e., Carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and 2,4-Dinitrophenol (DNP), and one moderate uncoupler, i.e., Sodium salicylate (NaSal). Quantitative expression studies demonstrated induction of transcripts encoding marA, soxS and acrB with NaSal and DNP, but not CCCP. Since MarA and SoxS are degraded by the Lon protease, we investigated the roles of Lon using a lon-deficient strain (Δlon). Compared to the wild-type strain, Δlon shows compromised growth upon exposure to NaSal or 2, 4-DNP. This sensitivity is dependent on marA but not rob and soxS. On the other hand, the Δlon strain shows enhanced growth in the presence of CCCP, which is dependent on acrB. Interestingly, NaSal and 2,4-DNP, but not CCCP, induce resistance to antibiotics, such as ciprofloxacin and tetracycline. This study addresses the effects of uncouplers and the roles of genes involved during bacterial growth and phenotypic antibiotic resistance. Strong uncouplers are often used to treat wastewater, and these results shed light on the possible mechanisms by which bacteria respond to uncouplers. Also, the rampant usage of some uncouplers to treat wastewater may lead to the development of antibiotic resistance.
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Affiliation(s)
- Taru Verma
- Department of Bioengineering, Indian Institute of Science, Bengaluru, 560012, India
| | - Santhi Sanil Nandini
- Department of Biochemistry, Indian Institute of Science, Bengaluru, 560012, India
| | - Varsha Singh
- Department of Biochemistry, Indian Institute of Science, Bengaluru, 560012, India
| | - Abinaya Raghavan
- Department of Biochemistry, Indian Institute of Science, Bengaluru, 560012, India
| | - Harshita Annappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru, 560012, India
| | - Chetana Bhaskarla
- Department of Biochemistry, Indian Institute of Science, Bengaluru, 560012, India
| | - Ashim Kumar Dubey
- Undergraduate program, Indian Institute of Science, Bengaluru, 560012, India
| | - Dipankar Nandi
- Department of Biochemistry, Indian Institute of Science, Bengaluru, 560012, India.
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5
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Voogdt CGP, Tripathi S, Bassler SO, McKeithen-Mead SA, Guiberson ER, Koumoutsi A, Bravo AM, Buie C, Zimmermann M, Sonnenburg JL, Typas A, Deutschbauer AM, Shiver AL, Huang KC. Randomly barcoded transposon mutant libraries for gut commensals II: Applying libraries for functional genetics. Cell Rep 2024; 43:113519. [PMID: 38142398 DOI: 10.1016/j.celrep.2023.113519] [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: 07/17/2023] [Revised: 10/22/2023] [Accepted: 11/14/2023] [Indexed: 12/26/2023] Open
Abstract
The critical role of the intestinal microbiota in human health and disease is well recognized. Nevertheless, there are still large gaps in our understanding of the functions and mechanisms encoded in the genomes of most members of the gut microbiota. Genome-scale libraries of transposon mutants are a powerful tool to help us address this gap. Recent advances in barcoded transposon mutagenesis have dramatically lowered the cost of mutant fitness determination in hundreds of in vitro and in vivo experimental conditions. In an accompanying review, we discuss recent advances and caveats for the construction of pooled and arrayed barcoded transposon mutant libraries in human gut commensals. In this review, we discuss how these libraries can be used across a wide range of applications, the technical aspects involved, and expectations for such screens.
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Affiliation(s)
- Carlos Geert Pieter Voogdt
- Genome Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany; Structural and Computational Biology Unit, EMBL, Heidelberg, Germany
| | - Surya Tripathi
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Stefan Oliver Bassler
- Genome Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany; Faculty of Biosciences, Heidelberg University, Grabengasse 1, 69117 Heidelberg, Germany
| | - Saria A McKeithen-Mead
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Emma R Guiberson
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alexandra Koumoutsi
- Genome Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Afonso Martins Bravo
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Cullen Buie
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Justin L Sonnenburg
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
| | - Athanasios Typas
- Genome Biology Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany; Structural and Computational Biology Unit, EMBL, Heidelberg, Germany.
| | - Adam M Deutschbauer
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Anthony L Shiver
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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6
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Govers SK, Campos M, Tyagi B, Laloux G, Jacobs-Wagner C. Apparent simplicity and emergent robustness in the control of the Escherichia coli cell cycle. Cell Syst 2024; 15:19-36.e5. [PMID: 38157847 DOI: 10.1016/j.cels.2023.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 06/15/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024]
Abstract
To examine how bacteria achieve robust cell proliferation across diverse conditions, we developed a method that quantifies 77 cell morphological, cell cycle, and growth phenotypes of a fluorescently labeled Escherichia coli strain and >800 gene deletion derivatives under multiple nutrient conditions. This approach revealed extensive phenotypic plasticity and deviating mutant phenotypes were often nutrient dependent. From this broad phenotypic landscape emerged simple and robust unifying rules (laws) that connect DNA replication initiation, nucleoid segregation, FtsZ ring formation, and cell constriction to specific aspects of cell size (volume, length, or added length) at the population level. Furthermore, completion of cell division followed the initiation of cell constriction after a constant time delay across strains and nutrient conditions, identifying cell constriction as a key control point for cell size determination. Our work provides a population-level description of the governing principles by which E. coli integrates cell cycle processes and growth rate with cell size to achieve its robust proliferative capability. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Sander K Govers
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; de Duve Institute, UCLouvain, Brussels, Belgium; Department of Biology, KU Leuven, Leuven, Belgium
| | - Manuel Campos
- Centre de Biologie Intégrative de Toulouse, Laboratoire de Microbiologie et Génétique Moléculaires, Université de Toulouse, Toulouse, France
| | - Bhavyaa Tyagi
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | | | - Christine Jacobs-Wagner
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA; Sarafan Chemistry, Engineering Medicine for Human Health Institute, Stanford University, Stanford, CA 94305, USA; Department of Microbiology and Immunology, Stanford School of Medicine, Stanford, CA 94305, USA.
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7
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Mohler K, Moen JM, Rogulina S, Rinehart J. System-wide optimization of an orthogonal translation system with enhanced biological tolerance. Mol Syst Biol 2023; 19:e10591. [PMID: 37477096 PMCID: PMC10407733 DOI: 10.15252/msb.202110591] [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: 07/20/2021] [Revised: 07/05/2023] [Accepted: 07/05/2023] [Indexed: 07/22/2023] Open
Abstract
Over the past two decades, synthetic biological systems have revolutionized the study of cellular physiology. The ability to site-specifically incorporate biologically relevant non-standard amino acids using orthogonal translation systems (OTSs) has proven particularly useful, providing unparalleled access to cellular mechanisms modulated by post-translational modifications, such as protein phosphorylation. However, despite significant advances in OTS design and function, the systems-level biology of OTS development and utilization remains underexplored. In this study, we employ a phosphoserine OTS (pSerOTS) as a model to systematically investigate global interactions between OTS components and the cellular environment, aiming to improve OTS performance. Based on this analysis, we design OTS variants to enhance orthogonality by minimizing host process interactions and reducing stress response activation. Our findings advance understanding of system-wide OTS:host interactions, enabling informed design practices that circumvent deleterious interactions with host physiology while improving OTS performance and stability. Furthermore, our study emphasizes the importance of establishing a pipeline for systematically profiling OTS:host interactions to enhance orthogonality and mitigate mechanisms underlying OTS-mediated host toxicity.
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Affiliation(s)
- Kyle Mohler
- Department of Cellular & Molecular PhysiologyYale School of MedicineNew HavenCTUSA
- Systems Biology InstituteYale UniversityNew HavenCTUSA
| | - Jack M Moen
- Quantitative Biosciences Institute (QBI)University of California, San FranciscoSan FranciscoCAUSA
- 2QBI Coronavirus Research Group (QCRG)San FranciscoCAUSA
- Department of Cellular and Molecular PharmacologyUniversity of California, San FranciscoSan FranciscoCAUSA
| | - Svetlana Rogulina
- Department of Cellular & Molecular PhysiologyYale School of MedicineNew HavenCTUSA
- Systems Biology InstituteYale UniversityNew HavenCTUSA
| | - Jesse Rinehart
- Department of Cellular & Molecular PhysiologyYale School of MedicineNew HavenCTUSA
- Systems Biology InstituteYale UniversityNew HavenCTUSA
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8
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Winkler KR, Mizrahi V, Warner DF, De Wet TJ. High-throughput functional genomics: A (myco)bacterial perspective. Mol Microbiol 2023; 120:141-158. [PMID: 37278255 PMCID: PMC10953053 DOI: 10.1111/mmi.15103] [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: 01/30/2020] [Revised: 04/06/2023] [Accepted: 05/21/2023] [Indexed: 06/07/2023]
Abstract
Advances in sequencing technologies have enabled unprecedented insights into bacterial genome composition and dynamics. However, the disconnect between the rapid acquisition of genomic data and the (much slower) confirmation of inferred genetic function threatens to widen unless techniques for fast, high-throughput functional validation can be applied at scale. This applies equally to Mycobacterium tuberculosis, the leading infectious cause of death globally and a pathogen whose genome, despite being among the first to be sequenced two decades ago, still contains many genes of unknown function. Here, we summarize the evolution of bacterial high-throughput functional genomics, focusing primarily on transposon (Tn)-based mutagenesis and the construction of arrayed mutant libraries in diverse bacterial systems. We also consider the contributions of CRISPR interference as a transformative technique for probing bacterial gene function at scale. Throughout, we situate our analysis within the context of functional genomics of mycobacteria, focusing specifically on the potential to yield insights into M. tuberculosis pathogenicity and vulnerabilities for new drug and regimen development. Finally, we offer suggestions for future approaches that might be usefully applied in elucidating the complex cellular biology of this major human pathogen.
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Affiliation(s)
- Kristy R. Winkler
- Molecular Mycobacteriology Research Unit and DSI/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular MedicineUniversity of Cape TownRondeboschSouth Africa
| | - Valerie Mizrahi
- Molecular Mycobacteriology Research Unit and DSI/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular MedicineUniversity of Cape TownRondeboschSouth Africa
- Wellcome Centre for Infectious Diseases Research in AfricaUniversity of Cape TownRondeboschSouth Africa
| | - Digby F. Warner
- Molecular Mycobacteriology Research Unit and DSI/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular MedicineUniversity of Cape TownRondeboschSouth Africa
- Wellcome Centre for Infectious Diseases Research in AfricaUniversity of Cape TownRondeboschSouth Africa
| | - Timothy J. De Wet
- Molecular Mycobacteriology Research Unit and DSI/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology and Institute of Infectious Disease and Molecular MedicineUniversity of Cape TownRondeboschSouth Africa
- Wellcome Centre for Infectious Diseases Research in AfricaUniversity of Cape TownRondeboschSouth Africa
- Department of Integrative Biomedical SciencesUniversity of Cape TownRondeboschSouth Africa
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9
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Santin YG, Lamot T, van Raaphorst R, Kaljević J, Laloux G. Modulation of prey size reveals adaptability and robustness in the cell cycle of an intracellular predator. Curr Biol 2023:S0960-9822(23)00541-9. [PMID: 37207648 DOI: 10.1016/j.cub.2023.04.059] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/14/2023] [Accepted: 04/25/2023] [Indexed: 05/21/2023]
Abstract
Despite a remarkable diversity of lifestyles, bacterial replication has only been investigated in a few model species. In bacteria that do not rely on canonical binary division for proliferation, the coordination of major cellular processes is still largely mysterious. Moreover, the dynamics of bacterial growth and division remain unexplored within spatially confined niches where nutrients are limited. This includes the life cycle of the model endobiotic predatory bacterium Bdellovibrio bacteriovorus, which grows by filamentation within its prey and produces a variable number of daughter cells. Here, we examined the impact of the micro-compartment in which predators replicate (i.e., the prey bacterium) on their cell-cycle progression at the single-cell level. Using Escherichia coli with genetically encoded size differences, we show that the duration of the predator cell cycle scales with prey size. Consequently, prey size determines predator offspring numbers. We found that individual predators elongate exponentially, with a growth rate determined by the nutritional quality of the prey, irrespective of prey size. However, the size of newborn predator cells is remarkably stable across prey nutritional content and size variations. Tuning the predatory cell cycle by modulating prey dimensions also allowed us to reveal invariable temporal connections between key cellular processes. Altogether, our data imply adaptability and robustness shaping the enclosed cell-cycle progression of B. bacteriovorus, which might contribute to optimal exploitation of the finite resources and space in their prey. This study extends the characterization of cell cycle control strategies and growth patterns beyond canonical models and lifestyles.
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Affiliation(s)
- Yoann G Santin
- de Duve Institute, UCLouvain, 75 avenue Hippocrate, 1200 Brussels, Belgium
| | - Thomas Lamot
- de Duve Institute, UCLouvain, 75 avenue Hippocrate, 1200 Brussels, Belgium
| | | | - Jovana Kaljević
- de Duve Institute, UCLouvain, 75 avenue Hippocrate, 1200 Brussels, Belgium
| | - Géraldine Laloux
- de Duve Institute, UCLouvain, 75 avenue Hippocrate, 1200 Brussels, Belgium.
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10
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McGuire BE, Nano FE. Whole-genome sequencing analysis of two heat-evolved Escherichia coli strains. BMC Genomics 2023; 24:154. [PMID: 36973666 PMCID: PMC10044804 DOI: 10.1186/s12864-023-09266-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/21/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND High temperatures cause a suite of problems for cells, including protein unfolding and aggregation; increased membrane fluidity; and changes in DNA supercoiling, RNA stability, transcription and translation. Consequently, enhanced thermotolerance can evolve through an unknown number of genetic mechanisms even in the simple model bacterium Escherichia coli. To date, each E. coli study exploring this question resulted in a different set of mutations. To understand the changes that can arise when an organism evolves to grow at higher temperatures, we sequenced and analyzed two previously described E. coli strains, BM28 and BM28 ΔlysU, that have been laboratory adapted to the highest E. coli growth temperature reported to date. RESULTS We found three large deletions in the BM28 and BM28 ΔlysU strains of 123, 15 and 8.5 kb in length and an expansion of IS10 elements. We found that BM28 and BM28 ΔlysU have considerably different genomes, suggesting that the BM28 culture that gave rise to BM28 and BM28 ΔlysU was a mixed population of genetically different cells. Consistent with published findings of high GroESL expression in BM28, we found that BM28 inexplicitly carries the groESL bearing plasmid pOF39 that was maintained simply by high-temperature selection pressure. We identified over 200 smaller insertions, deletions, single nucleotide polymorphisms and other mutations, including changes in master regulators such as the RNA polymerase and the transcriptional termination factor Rho. Importantly, this genome analysis demonstrates that the commonly cited findings that LysU plays a crucial role in thermotolerance and that GroESL hyper-expression is brought about by chromosomal mutations are based on a previous misinterpretation of the genotype of BM28. CONCLUSIONS This whole-genome sequencing study describes genetically distinct mechanisms of thermotolerance evolution from those found in other heat-evolved E. coli strains. Studying adaptive laboratory evolution to heat in simple model organisms is important in the context of climate change. It is important to better understand genetic mechanisms of enhancing thermotolerance in bacteria and other organisms, both in terms of optimizing laboratory evolution methods for various organisms and in terms of potential genetic engineering of organisms most at risk or most important to our societies and ecosystems.
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Affiliation(s)
- Bailey E McGuire
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, B.C, Canada.
| | - Francis E Nano
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, B.C, Canada
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11
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Tian D, Wang C, Liu Y, Zhang Y, Caliari A, Lu H, Xia Y, Xu B, Xu J, Yomo T. Cell Sorting-Directed Selection of Bacterial Cells in Bigger Sizes Analyzed by Imaging Flow Cytometry during Experimental Evolution. Int J Mol Sci 2023; 24:ijms24043243. [PMID: 36834655 PMCID: PMC9966196 DOI: 10.3390/ijms24043243] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/20/2023] [Accepted: 01/26/2023] [Indexed: 02/10/2023] Open
Abstract
Cell morphology is an essential and phenotypic trait that can be easily tracked during adaptation and evolution to environmental changes. Thanks to the rapid development of quantitative analytical techniques for large populations of cells based on their optical properties, morphology can be easily determined and tracked during experimental evolution. Furthermore, the directed evolution of new culturable morphological phenotypes can find use in synthetic biology to refine fermentation processes. It remains unknown whether and how fast we can obtain a stable mutant with distinct morphologies using fluorescence-activated cell sorting (FACS)-directed experimental evolution. Taking advantage of FACS and imaging flow cytometry (IFC), we direct the experimental evolution of the E. coli population undergoing continuous passage of sorted cells with specific optical properties. After ten rounds of sorting and culturing, a lineage with large cells resulting from incomplete closure of the division ring was obtained. Genome sequencing highlighted a stop-gain mutation in amiC, leading to a dysfunctional AmiC division protein. The combination of FACS-based selection with IFC analysis to track the evolution of the bacteria population in real-time holds promise to rapidly select and culture new morphologies and association tendencies with many potential applications.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jian Xu
- Correspondence: (J.X.); (T.Y.); Tel.: +86-(21)-62233727 (J.X. & T.Y.)
| | - Tetsuya Yomo
- Correspondence: (J.X.); (T.Y.); Tel.: +86-(21)-62233727 (J.X. & T.Y.)
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12
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Li F, Wang MM, Liu QH, Ma ZW, Wang JJ, Wang ZY, Tang JW, Lyu JW, Zhu ZB, Wang L. Molecular mechanisms of glycogen particle assembly in Escherichia coli. Carbohydr Polym 2023; 299:120200. [PMID: 36876811 DOI: 10.1016/j.carbpol.2022.120200] [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: 09/14/2022] [Revised: 10/02/2022] [Accepted: 10/05/2022] [Indexed: 11/09/2022]
Abstract
It has been reported that glycogen in Escherichia coli has two structural states, that is, fragility and stability, which alters dynamically. However, molecular mechanisms behind the structural alterations are not fully understood. In this study, we focused on the potential roles of two important glycogen degradation enzymes, glycogen phosphorylase (glgP) and glycogen debranching enzyme (glgX), in glycogen structural alterations. The fine molecular structure of glycogen particles in Escherichia coli and three mutants (ΔglgP, ΔglgX and ΔglgP/ΔglgX) were examined, which showed that glycogen in E. coli ΔglgP and E. coli ΔglgP/ΔglgX were consistently fragile while being consistently stable in E. coli ΔglgX, indicating the dominant role of GP in glycogen structural stability control. In sum, our study concludes that glycogen phosphorylase is essential in glycogen structural stability, leading to molecular insights into structural assembly of glycogen particles in E. coli.
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Affiliation(s)
- Fen Li
- Laboratory Medicine, The Fifth People's Hospital of Huai'an, Huai'an, Jiangsu Province, China
| | - Meng-Meng Wang
- Department of Pharmacy, Qingdao Eighth People's Hospital, Qingdao, Shandong Province, China; Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Qing-Hua Liu
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Zhang-Wen Ma
- Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Jun-Jiao Wang
- Department of Intelligent Medical Engineering, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Zi-Yi Wang
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Jia-Wei Tang
- Department of Intelligent Medical Engineering, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, Jiangsu Province, China
| | - Jing-Wen Lyu
- Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China
| | - Zuo-Bin Zhu
- Department of Genetics, School of Life Sciences, Xuzhou Medical University, Xuzhou, Jiangsu Province, China.
| | - Liang Wang
- Laboratory Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China.
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13
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Arjes HA, Sun J, Liu H, Nguyen TH, Culver RN, Celis AI, Walton SJ, Vasquez KS, Yu FB, Xue KS, Newton D, Zermeno R, Weglarz M, Deutschbauer A, Huang KC, Shiver AL. Construction and characterization of a genome-scale ordered mutant collection of Bacteroides thetaiotaomicron. BMC Biol 2022; 20:285. [PMID: 36527020 PMCID: PMC9758874 DOI: 10.1186/s12915-022-01481-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Ordered transposon-insertion collections, in which specific transposon-insertion mutants are stored as monocultures in a genome-scale collection, represent a promising tool for genetic dissection of human gut microbiota members. However, publicly available collections are scarce and the construction methodology remains in early stages of development. RESULTS Here, we describe the assembly of a genome-scale ordered collection of transposon-insertion mutants in the model gut anaerobe Bacteroides thetaiotaomicron VPI-5482 that we created as a resource for the research community. We used flow cytometry to sort single cells from a pooled library, located mutants within this initial progenitor collection by applying a pooling strategy with barcode sequencing, and re-arrayed specific mutants to create a condensed collection with single-insertion strains covering >2500 genes. To demonstrate the potential of the condensed collection for phenotypic screening, we analyzed growth dynamics and cell morphology. We identified both growth defects and altered cell shape in mutants disrupting sphingolipid synthesis and thiamine scavenging. Finally, we analyzed the process of assembling the B. theta condensed collection to identify inefficiencies that limited coverage. We demonstrate as part of this analysis that the process of assembling an ordered collection can be accurately modeled using barcode sequencing data. CONCLUSION We expect that utilization of this ordered collection will accelerate research into B. theta physiology and that lessons learned while assembling the collection will inform future efforts to assemble ordered mutant collections for an increasing number of gut microbiota members.
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Affiliation(s)
- Heidi A. Arjes
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA
| | - Jiawei Sun
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA
| | - Hualan Liu
- grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA
| | - Taylor H. Nguyen
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA
| | - Rebecca N. Culver
- grid.168010.e0000000419368956Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Arianna I. Celis
- grid.168010.e0000000419368956Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Sophie Jean Walton
- grid.168010.e0000000419368956Biophysics Training Program, Stanford University School of Medicine, Stanford, CA USA
| | - Kimberly S. Vasquez
- grid.168010.e0000000419368956Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Feiqiao Brian Yu
- grid.499295.a0000 0004 9234 0175Chan Zuckerberg Biohub, San Francisco, CA 94158 USA
| | - Katherine S. Xue
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Daniel Newton
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA
| | - Ricardo Zermeno
- grid.168010.e0000000419368956Stanford Shared FACS Facility, Center for Molecular and Genetic Medicine, Stanford University, Stanford, CA USA
| | - Meredith Weglarz
- grid.168010.e0000000419368956Stanford Shared FACS Facility, Center for Molecular and Genetic Medicine, Stanford University, Stanford, CA USA
| | - Adam Deutschbauer
- grid.184769.50000 0001 2231 4551Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA USA ,grid.47840.3f0000 0001 2181 7878Department of Plant and Microbial Biology, University of California, Berkeley, CA USA
| | - Kerwyn Casey Huang
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA ,grid.168010.e0000000419368956Biophysics Training Program, Stanford University School of Medicine, Stanford, CA USA ,grid.168010.e0000000419368956Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305 USA ,grid.499295.a0000 0004 9234 0175Chan Zuckerberg Biohub, San Francisco, CA 94158 USA
| | - Anthony L. Shiver
- grid.168010.e0000000419368956Department of Bioengineering, Stanford University, Stanford, CA USA
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14
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Kellogg DR, Levin PA. Nutrient availability as an arbiter of cell size. Trends Cell Biol 2022; 32:908-919. [PMID: 35851491 PMCID: PMC9588502 DOI: 10.1016/j.tcb.2022.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/07/2022] [Accepted: 06/16/2022] [Indexed: 01/21/2023]
Abstract
Pioneering work carried out over 60 years ago discovered that bacterial cell size is proportional to the growth rate set by nutrient availability. This relationship is traditionally referred to as the 'growth law'. Subsequent studies revealed the growth law to hold across all orders of life, a remarkable degree of conservation. However, recent work suggests the relationship between growth rate, nutrients, and cell size is far more complicated and less deterministic than originally thought. Focusing on bacteria and yeast, here we review efforts to understand the molecular mechanisms underlying the relationship between growth rate and cell size.
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Affiliation(s)
- Douglas R Kellogg
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA 95064, USA.
| | - Petra Anne Levin
- Department of Biology, Washington University in St. Louis, St Louis, MO 63130, USA; Center for Science & Engineering of Living Systems (CSELS), McKelvey School of Engineering, Washington University in St Louis, St Louis, MO 63130, USA.
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15
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Shibai A, Kotani H, Sakata N, Furusawa C, Tsuru S. Purifying selection enduringly acts on the sequence evolution of highly expressed proteins in Escherichia coli. G3 GENES|GENOMES|GENETICS 2022; 12:6694045. [PMID: 36073932 PMCID: PMC9635659 DOI: 10.1093/g3journal/jkac235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/27/2022] [Indexed: 11/17/2022]
Abstract
The evolutionary speed of a protein sequence is constrained by its expression level, with highly expressed proteins evolving relatively slowly. This negative correlation between expression levels and evolutionary rates (known as the E–R anticorrelation) has already been widely observed in past macroevolution between species from bacteria to animals. However, it remains unclear whether this seemingly general law also governs recent evolution, including past and de novo, within a species. However, the advent of genomic sequencing and high-throughput phenotyping, particularly for bacteria, has revealed fundamental gaps between the 2 evolutionary processes and has provided empirical data opposing the possible underlying mechanisms which are widely believed. These conflicts raise questions about the generalization of the E–R anticorrelation and the relevance of plausible mechanisms. To explore the ubiquitous impact of expression levels on molecular evolution and test the relevance of the possible underlying mechanisms, we analyzed the genome sequences of 99 strains of Escherichia coli for evolution within species in nature. We also analyzed genomic mutations accumulated under laboratory conditions as a model of de novo evolution within species. Here, we show that E–R anticorrelation is significant in both past and de novo evolution within species in E. coli. Our data also confirmed ongoing purifying selection on highly expressed genes. Ongoing selection included codon-level purifying selection, supporting the relevance of the underlying mechanisms. However, the impact of codon-level purifying selection on the constraints in evolution within species might be smaller than previously expected from evolution between species.
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Affiliation(s)
- Atsushi Shibai
- Center for Biosystems Dynamics Research (BDR), RIKEN , Osaka 565-0874, Japan
| | - Hazuki Kotani
- Center for Biosystems Dynamics Research (BDR), RIKEN , Osaka 565-0874, Japan
| | - Natsue Sakata
- Center for Biosystems Dynamics Research (BDR), RIKEN , Osaka 565-0874, Japan
| | - Chikara Furusawa
- Center for Biosystems Dynamics Research (BDR), RIKEN , Osaka 565-0874, Japan
- Universal Biology Institute, School of Science, The University of Tokyo , Tokyo 113-0033, Japan
| | - Saburo Tsuru
- Universal Biology Institute, School of Science, The University of Tokyo , Tokyo 113-0033, Japan
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16
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Aida H, Hashizume T, Ashino K, Ying BW. Machine learning-assisted discovery of growth decision elements by relating bacterial population dynamics to environmental diversity. eLife 2022; 11:76846. [PMID: 36017903 PMCID: PMC9417415 DOI: 10.7554/elife.76846] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 08/15/2022] [Indexed: 12/30/2022] Open
Abstract
Microorganisms growing in their habitat constitute a complex system. How the individual constituents of the environment contribute to microbial growth remains largely unknown. The present study focused on the contribution of environmental constituents to population dynamics via a high-throughput assay and data-driven analysis of a wild-type Escherichia coli strain. A large dataset constituting a total of 12,828 bacterial growth curves with 966 medium combinations, which were composed of 44 pure chemical compounds, was acquired. Machine learning analysis of the big data relating the growth parameters to the medium combinations revealed that the decision-making components for bacterial growth were distinct among various growth phases, e.g., glucose, sulfate, and serine for maximum growth, growth rate, and growth delay, respectively. Further analyses and simulations indicated that branched-chain amino acids functioned as global coordinators for population dynamics, as well as a survival strategy of risk diversification to prevent the bacterial population from undergoing extinction.
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Affiliation(s)
- Honoka Aida
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takamasa Hashizume
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Kazuha Ashino
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Bei-Wen Ying
- School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
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17
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Silvis MR, Rajendram M, Shi H, Osadnik H, Gray AN, Cesar S, Peters JM, Hearne CC, Kumar P, Todor H, Huang KC, Gross CA. Morphological and Transcriptional Responses to CRISPRi Knockdown of Essential Genes in Escherichia coli. mBio 2021; 12:e0256121. [PMID: 34634934 PMCID: PMC8510551 DOI: 10.1128/mbio.02561-21] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 01/03/2023] Open
Abstract
CRISPR interference (CRISPRi) has facilitated the study of essential genes in diverse organisms using both high-throughput and targeted approaches. Despite the promise of this technique, no comprehensive arrayed CRISPRi library targeting essential genes exists for the model bacterium Escherichia coli, or for any Gram-negative species. Here, we built and characterized such a library. Each of the ∼500 strains in our E. coli library contains an inducible, chromosomally integrated single guide RNA (sgRNA) targeting an essential (or selected nonessential) gene and can be mated with a pseudo-Hfr donor strain carrying a dcas9 cassette to create a CRISPRi knockdown strain. Using this system, we built an arrayed library of CRISPRi strains and performed population and single-cell growth and morphology measurements as well as targeted follow-up experiments. These studies found that inhibiting translation causes an extended lag phase, identified new modulators of cell morphology, and revealed that the morphogene mreB is subject to transcriptional feedback regulation, which is critical for the maintenance of morphology. Our findings highlight canonical and noncanonical roles for essential genes in numerous aspects of cellular homeostasis. IMPORTANCE Essential genes make up only ∼5 to 10% of the genetic complement in most organisms but occupy much of their protein synthesis and account for almost all antibiotic targets. Despite the importance of essential genes, their intractability has, until recently, hampered efforts to study them. CRISPRi has facilitated the study of essential genes by allowing inducible and titratable depletion. However, all large-scale CRISPRi studies in Gram-negative bacteria thus far have used plasmids to express CRISPRi components and have been constructed in pools, limiting their utility for targeted assays and complicating the determination of antibiotic effects. Here, we use a modular method to construct an arrayed library of chromosomally integrated CRISPRi strains targeting the essential genes of the model bacterium Escherichia coli. This library enables targeted studies of essential gene depletions and high-throughput determination of antibiotic targets and facilitates studies targeting the outer membrane, an essential component that serves as the major barrier to antibiotics.
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Affiliation(s)
- Melanie R. Silvis
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Manohary Rajendram
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Hendrik Osadnik
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Andrew N. Gray
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Spencer Cesar
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Jason M. Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin—Madison, Madison, Wisconsin, USA
| | - Cameron C. Hearne
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Parth Kumar
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Horia Todor
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
| | - Carol A. Gross
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, California, USA
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18
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Belliveau NM, Chure G, Hueschen CL, Garcia HG, Kondev J, Fisher DS, Theriot JA, Phillips R. Fundamental limits on the rate of bacterial growth and their influence on proteomic composition. Cell Syst 2021; 12:924-944.e2. [PMID: 34214468 PMCID: PMC8460600 DOI: 10.1016/j.cels.2021.06.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/12/2021] [Accepted: 06/04/2021] [Indexed: 12/11/2022]
Abstract
Despite abundant measurements of bacterial growth rate, cell size, and protein content, we lack a rigorous understanding of what sets the scale of these quantities and when protein abundances should (or should not) depend on growth rate. Here, we estimate the basic requirements and physical constraints on steady-state growth by considering key processes in cellular physiology across a collection of Escherichia coli proteomic data covering ≈4,000 proteins and 36 growth rates. Our analysis suggests that cells are predominantly tuned for the task of cell doubling across a continuum of growth rates; specific processes do not limit growth rate or dictate cell size. We present a model of proteomic regulation as a function of nutrient supply that reconciles observed interdependences between protein synthesis, cell size, and growth rate and propose that a theoretical inability to parallelize ribosomal synthesis places a firm limit on the achievable growth rate. A record of this paper's transparent peer review process is included in the supplemental information.
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Affiliation(s)
- Nathan M Belliveau
- Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA
| | - Griffin Chure
- Department of Applied Physics, California Institute of Technology, Pasadena, CA 91125, USA
| | - Christina L Hueschen
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Hernan G Garcia
- Department of Molecular Cell Biology and Department of Physics, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jane Kondev
- Department of Physics, Brandeis University, Waltham, MA 02453, USA
| | - Daniel S Fisher
- Department of Applied Physics, Stanford University, Stanford, CA 94305, USA
| | - Julie A Theriot
- Department of Biology, Howard Hughes Medical Institute, University of Washington, Seattle, WA 98105, USA.
| | - Rob Phillips
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA.
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19
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Meunier A, Cornet F, Campos M. Bacterial cell proliferation: from molecules to cells. FEMS Microbiol Rev 2021; 45:5912836. [PMID: 32990752 PMCID: PMC7794046 DOI: 10.1093/femsre/fuaa046] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/10/2020] [Indexed: 12/11/2022] Open
Abstract
Bacterial cell proliferation is highly efficient, both because bacteria grow fast and multiply with a low failure rate. This efficiency is underpinned by the robustness of the cell cycle and its synchronization with cell growth and cytokinesis. Recent advances in bacterial cell biology brought about by single-cell physiology in microfluidic chambers suggest a series of simple phenomenological models at the cellular scale, coupling cell size and growth with the cell cycle. We contrast the apparent simplicity of these mechanisms based on the addition of a constant size between cell cycle events (e.g. two consecutive initiation of DNA replication or cell division) with the complexity of the underlying regulatory networks. Beyond the paradigm of cell cycle checkpoints, the coordination between the DNA and division cycles and cell growth is largely mediated by a wealth of other mechanisms. We propose our perspective on these mechanisms, through the prism of the known crosstalk between DNA replication and segregation, cell division and cell growth or size. We argue that the precise knowledge of these molecular mechanisms is critical to integrate the diverse layers of controls at different time and space scales into synthetic and verifiable models.
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Affiliation(s)
- Alix Meunier
- Centre de Biologie Intégrative de Toulouse (CBI Toulouse), Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Université de Toulouse, UPS, CNRS, IBCG, 165 rue Marianne Grunberg-Manago, 31062 Toulouse, France
| | - François Cornet
- Centre de Biologie Intégrative de Toulouse (CBI Toulouse), Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Université de Toulouse, UPS, CNRS, IBCG, 165 rue Marianne Grunberg-Manago, 31062 Toulouse, France
| | - Manuel Campos
- Centre de Biologie Intégrative de Toulouse (CBI Toulouse), Laboratoire de Microbiologie et Génétique Moléculaires (LMGM), Université de Toulouse, UPS, CNRS, IBCG, 165 rue Marianne Grunberg-Manago, 31062 Toulouse, France
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20
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Jeckel H, Drescher K. Advances and opportunities in image analysis of bacterial cells and communities. FEMS Microbiol Rev 2021; 45:fuaa062. [PMID: 33242074 PMCID: PMC8371272 DOI: 10.1093/femsre/fuaa062] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022] Open
Abstract
The cellular morphology and sub-cellular spatial structure critically influence the function of microbial cells. Similarly, the spatial arrangement of genotypes and phenotypes in microbial communities has important consequences for cooperation, competition, and community functions. Fluorescence microscopy techniques are widely used to measure spatial structure inside living cells and communities, which often results in large numbers of images that are difficult or impossible to analyze manually. The rapidly evolving progress in computational image analysis has recently enabled the quantification of a large number of properties of single cells and communities, based on traditional analysis techniques and convolutional neural networks. Here, we provide a brief introduction to core concepts of automated image processing, recent software tools and how to validate image analysis results. We also discuss recent advances in image analysis of microbial cells and communities, and how these advances open up opportunities for quantitative studies of spatiotemporal processes in microbiology, based on image cytometry and adaptive microscope control.
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Affiliation(s)
- Hannah Jeckel
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
- Department of Physics, Philipps-Universität Marburg, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
- Synmikro Center for Synthetic Microbiology, Karl-von-Frisch-Str. 16, 35043 Marburg, Germany
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21
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Mastering the Gram-negative bacterial barrier - Chemical approaches to increase bacterial bioavailability of antibiotics. Adv Drug Deliv Rev 2021; 172:339-360. [PMID: 33705882 DOI: 10.1016/j.addr.2021.02.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/08/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023]
Abstract
To win the battle against resistant, pathogenic bacteria, novel classes of anti-infectives and targets are urgently needed. Bacterial uptake, distribution, metabolic and efflux pathways of antibiotics in Gram-negative bacteria determine what we here refer to as bacterial bioavailability. Understanding these mechanisms from a chemical perspective is essential for anti-infective activity and hence, drug discovery as well as drug delivery. A systematic and critical discussion of in bacterio, in vitro and in silico assays reveals that a sufficiently accurate holistic approach is still missing. We expect new findings based on Gram-negative bacterial bioavailability to guide future anti-infective research.
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22
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Zhu L, Rajendram M, Huang KC. Effects of fixation on bacterial cellular dimensions and integrity. iScience 2021; 24:102348. [PMID: 33912815 PMCID: PMC8066382 DOI: 10.1016/j.isci.2021.102348] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 01/25/2021] [Accepted: 03/18/2021] [Indexed: 11/22/2022] Open
Abstract
Fixation facilitates imaging of subcellular localization and cell morphology, yet it remains unknown how fixation affects cellular dimensions and intracellular fluorescence patterns, particularly during long-term storage. Here, we characterized the effects of multiple fixatives on several bacterial species. Fixation generally reduced cell length by 5-15%; single-cell tracking in microfluidics revealed that the length decrease was an aggregate effect of many steps in the fixation protocol and that fluorescence of cytoplasmic GFP but not membrane-bound MreB-msfGFP was rapidly lost with formaldehyde-based fixatives. Cellular dimensions were preserved in formaldehyde-based fixatives for ≥4 days, but methanol caused length to decrease. Although methanol preserved cytoplasmic fluorescence better than formaldehyde-based fixatives, some Escherichia coli cells were able to grow directly after fixation. Moreover, methanol fixation caused lysis in a subpopulation of cells, with virtually all Bacillus subtilis cells lysing after one day. These findings highlight tradeoffs between maintenance of fluorescence and membrane integrity for future applications of fixation.
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Affiliation(s)
- Lillian Zhu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Manohary Rajendram
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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23
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Gilmore MC, Ritzl-Rinkenberger B, Cava F. An updated toolkit for exploring bacterial cell wall structure and dynamics. Fac Rev 2021; 10:14. [PMID: 33659932 PMCID: PMC7894271 DOI: 10.12703/r/10-14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The bacterial cell wall is made primarily from peptidoglycan, a complex biomolecule which forms a bag-like exoskeleton that envelops the cell. As it is unique to bacteria and typically essential for their growth and survival, it represents one of the most successful targets for antibiotics. Although peptidoglycan has been studied intensively for over 50 years, the past decade has seen major steps in our understanding of this molecule because of the advent of new analytical and imaging methods. Here, we outline the most recent developments in tools that have helped to elucidate peptidoglycan structure and dynamics.
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Affiliation(s)
- Michael C Gilmore
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Barbara Ritzl-Rinkenberger
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå University, Umeå, Sweden
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24
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Jorgenson MA, Bryant JC. A genetic screen to identify factors affected by undecaprenyl phosphate recycling uncovers novel connections to morphogenesis in Escherichia coli. Mol Microbiol 2021; 115:191-207. [PMID: 32979869 PMCID: PMC10568968 DOI: 10.1111/mmi.14609] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/11/2020] [Indexed: 01/30/2023]
Abstract
Undecaprenyl phosphate (Und-P) is an essential lipid carrier that ferries cell wall intermediates across the cytoplasmic membrane in bacteria. Und-P is generated by dephosphorylating undecaprenyl pyrophosphate (Und-PP). In Escherichia coli, BacA, PgpB, YbjG, and LpxT dephosphorylate Und-PP and are conditionally essential. To identify vulnerabilities that arise when Und-P metabolism is defective, we developed a genetic screen for synthetic interactions which, in combination with ΔybjG ΔlpxT ΔbacA, are lethal or reduce fitness. The screen uncovered novel connections to cell division, DNA replication/repair, signal transduction, and glutathione metabolism. Further analysis revealed several new morphogenes; loss of one of these, qseC, caused cells to enlarge and lyse. QseC is the sensor kinase component of the QseBC two-component system. Loss of QseC causes overactivation of the QseB response regulator by PmrB cross-phosphorylation. Here, we show that deleting qseB completely reverses the shape defect of ΔqseC cells, as does overexpressing rprA (a small RNA). Surprisingly, deleting pmrB only partially suppressed qseC-related shape defects. Thus, QseB is activated by multiple factors in QseC's absence and prior functions ascribed to QseBC may originate from cell wall defects. Altogether, our findings provide a framework for identifying new determinants of cell integrity that could be targeted in future therapies.
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Affiliation(s)
- Matthew A. Jorgenson
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
| | - Joseph C. Bryant
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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25
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Wu PIF, Ross C, Siegele DA, Hu JC. Insights from the reanalysis of high-throughput chemical genomics data for Escherichia coli K-12. G3-GENES GENOMES GENETICS 2021; 11:6044125. [PMID: 33561236 PMCID: PMC8022724 DOI: 10.1093/g3journal/jkaa035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 11/11/2020] [Indexed: 11/14/2022]
Abstract
Despite the demonstrated success of genome-wide genetic screens and chemical genomics studies at predicting functions for genes of unknown function or predicting new functions for well-characterized genes, their potential to provide insights into gene function has not been fully explored. We systematically reanalyzed a published high-throughput phenotypic dataset for the model Gram-negative bacterium Escherichia coli K-12. The availability of high-quality annotation sets allowed us to compare the power of different metrics for measuring phenotypic profile similarity to correctly infer gene function. We conclude that there is no single best method; the three metrics tested gave comparable results for most gene pairs. We also assessed how converting quantitative phenotypes to discrete, qualitative phenotypes affected the association between phenotype and function. Our results indicate that this approach may allow phenotypic data from different studies to be combined to produce a larger dataset that may reveal functional connections between genes not detected in individual studies.
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Affiliation(s)
- Peter I-Fan Wu
- Department of Biochemistry and Biophysics, Texas A&M University and Texas Agrilife Research, College Station, TX 77843-2128, USA
| | - Curtis Ross
- Department of Biochemistry and Biophysics, Texas A&M University and Texas Agrilife Research, College Station, TX 77843-2128, USA
| | - Deborah A Siegele
- Department of Biology, Texas A&M University, College Station, TX 77843-3258, USA
| | - James C Hu
- Department of Biochemistry and Biophysics, Texas A&M University and Texas Agrilife Research, College Station, TX 77843-2128, USA
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26
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Genome-Wide Functional Screen for Calcium Transients in Escherichia coli Identifies Increased Membrane Potential Adaptation to Persistent DNA Damage. J Bacteriol 2021; 203:JB.00509-20. [PMID: 33199283 DOI: 10.1128/jb.00509-20] [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] [Received: 09/09/2020] [Accepted: 11/07/2020] [Indexed: 12/12/2022] Open
Abstract
Calcium plays numerous critical roles in signaling and homeostasis in eukaryotic cells. Far less is known about calcium signaling in bacteria than in eukaryotic cells, and few genes controlling influx and efflux have been identified. Previous work in Escherichia coli showed that calcium influx was induced by voltage depolarization, which was enhanced by mechanical stimulation, which suggested a role in bacterial mechanosensation. To identify proteins and pathways affecting calcium handling in bacteria, we designed a live-cell screen to monitor calcium dynamics in single cells across a genome-wide knockout panel in E. coli The screen measured cells from the Keio collection of knockouts and quantified calcium transients across the population. Overall, we found 143 gene knockouts that decreased levels of calcium transients and 32 gene knockouts that increased levels of transients. Knockouts of proteins involved in energy production and regulation appeared, as expected, as well as knockouts of proteins of a voltage sink, F1Fo-ATPase. Knockouts of exopolysaccharide and outer membrane synthesis proteins showed reduced transients which refined our model of electrophysiology-mediated mechanosensation. Additionally, knockouts of proteins associated with DNA repair had reduced calcium transients and voltage. However, acute DNA damage did not affect voltage, and the results suggested that only long-term adaptation to DNA damage decreased membrane potential and calcium transients. Our work showed a distinct separation between the acute and long-term DNA damage responses in bacteria, which also has implications for mitochondrial DNA damage in eukaryotes.IMPORTANCE All eukaryotic cells use calcium as a critical signaling molecule. There is tantalizing evidence that bacteria also use calcium for cellular signaling, but much less is known about the molecular actors and physiological roles. To identify genes regulating cytoplasmic calcium in Escherichia coli, we created a single-cell screen for modulators of calcium dynamics. The genes uncovered in this screen helped refine a model for voltage-mediated bacterial mechanosensation. Additionally, we were able to more carefully dissect the mechanisms of adaptation to long-term DNA damage, which has implications for both bacteria and mitochondria in the face of unrepaired DNA.
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27
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Straightening up for life in a biofilm. Proc Natl Acad Sci U S A 2020; 117:31573-31574. [PMID: 33203672 DOI: 10.1073/pnas.2021127117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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28
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Cambré A, Aertsen A. Bacterial Vivisection: How Fluorescence-Based Imaging Techniques Shed a Light on the Inner Workings of Bacteria. Microbiol Mol Biol Rev 2020; 84:e00008-20. [PMID: 33115939 PMCID: PMC7599038 DOI: 10.1128/mmbr.00008-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rise in fluorescence-based imaging techniques over the past 3 decades has improved the ability of researchers to scrutinize live cell biology at increased spatial and temporal resolution. In microbiology, these real-time vivisections structurally changed the view on the bacterial cell away from the "watery bag of enzymes" paradigm toward the perspective that these organisms are as complex as their eukaryotic counterparts. Capitalizing on the enormous potential of (time-lapse) fluorescence microscopy and the ever-extending pallet of corresponding probes, initial breakthroughs were made in unraveling the localization of proteins and monitoring real-time gene expression. However, later it became clear that the potential of this technique extends much further, paving the way for a focus-shift from observing single events within bacterial cells or populations to obtaining a more global picture at the intra- and intercellular level. In this review, we outline the current state of the art in fluorescence-based vivisection of bacteria and provide an overview of important case studies to exemplify how to use or combine different strategies to gain detailed information on the cell's physiology. The manuscript therefore consists of two separate (but interconnected) parts that can be read and consulted individually. The first part focuses on the fluorescent probe pallet and provides a perspective on modern methodologies for microscopy using these tools. The second section of the review takes the reader on a tour through the bacterial cell from cytoplasm to outer shell, describing strategies and methods to highlight architectural features and overall dynamics within cells.
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Affiliation(s)
- Alexander Cambré
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
| | - Abram Aertsen
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
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29
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de Wet TJ, Winkler KR, Mhlanga M, Mizrahi V, Warner DF. Arrayed CRISPRi and quantitative imaging describe the morphotypic landscape of essential mycobacterial genes. eLife 2020; 9:e60083. [PMID: 33155979 PMCID: PMC7647400 DOI: 10.7554/elife.60083] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/03/2020] [Indexed: 12/11/2022] Open
Abstract
Mycobacterium tuberculosis possesses a large number of genes of unknown or predicted function, undermining fundamental understanding of pathogenicity and drug susceptibility. To address this challenge, we developed a high-throughput functional genomics approach combining inducible CRISPR-interference and image-based analyses of morphological features and sub-cellular chromosomal localizations in the related non-pathogen, M. smegmatis. Applying automated imaging and analysis to 263 essential gene knockdown mutants in an arrayed library, we derive robust, quantitative descriptions of bacillary morphologies consequent on gene silencing. Leveraging statistical-learning, we demonstrate that functionally related genes cluster by morphotypic similarity and that this information can be used to inform investigations of gene function. Exploiting this observation, we infer the existence of a mycobacterial restriction-modification system, and identify filamentation as a defining mycobacterial response to histidine starvation. Our results support the application of large-scale image-based analyses for mycobacterial functional genomics, simultaneously establishing the utility of this approach for drug mechanism-of-action studies.
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Affiliation(s)
- Timothy J de Wet
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape TownSouth Africa
| | - Kristy R Winkler
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape TownSouth Africa
| | - Musa Mhlanga
- Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape TownSouth Africa
- Department of Integrative Biomedical Sciences, University of Cape TownCape TownSouth Africa
| | - Valerie Mizrahi
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape TownSouth Africa
- Wellcome Centre for Infectious Diseases Research in Africa, University of Cape TownCape TownSouth Africa
| | - Digby F Warner
- SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, Department of Pathology, University of Cape TownCape TownSouth Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape TownCape TownSouth Africa
- Wellcome Centre for Infectious Diseases Research in Africa, University of Cape TownCape TownSouth Africa
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30
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Atolia E, Cesar S, Arjes HA, Rajendram M, Shi H, Knapp BD, Khare S, Aranda-Díaz A, Lenski RE, Huang KC. Environmental and Physiological Factors Affecting High-Throughput Measurements of Bacterial Growth. mBio 2020; 11:e01378-20. [PMID: 33082255 PMCID: PMC7587430 DOI: 10.1128/mbio.01378-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/10/2020] [Indexed: 11/20/2022] Open
Abstract
Bacterial growth under nutrient-rich and starvation conditions is intrinsically tied to the environmental history and physiological state of the population. While high-throughput technologies have enabled rapid analyses of mutant libraries, technical and biological challenges complicate data collection and interpretation. Here, we present a framework for the execution and analysis of growth measurements with improved accuracy over that of standard approaches. Using this framework, we demonstrate key biological insights that emerge from consideration of culturing conditions and history. We determined that quantification of the background absorbance in each well of a multiwell plate is critical for accurate measurements of maximal growth rate. Using mathematical modeling, we demonstrated that maximal growth rate is dependent on initial cell density, which distorts comparisons across strains with variable lag properties. We established a multiple-passage protocol that alleviates the substantial effects of glycerol on growth in carbon-poor media, and we tracked growth rate-mediated fitness increases observed during a long-term evolution of Escherichia coli in low glucose concentrations. Finally, we showed that growth of Bacillus subtilis in the presence of glycerol induces a long lag in the next passage due to inhibition of a large fraction of the population. Transposon mutagenesis linked this phenotype to the incorporation of glycerol into lipoteichoic acids, revealing a new role for these envelope components in resuming growth after starvation. Together, our investigations underscore the complex physiology of bacteria during bulk passaging and the importance of robust strategies to understand and quantify growth.IMPORTANCE How starved bacteria adapt and multiply under replete nutrient conditions is intimately linked to their history of previous growth, their physiological state, and the surrounding environment. While automated equipment has enabled high-throughput growth measurements, data interpretation and knowledge gaps regarding the determinants of growth kinetics complicate comparisons between strains. Here, we present a framework for growth measurements that improves accuracy and attenuates the effects of growth history. We determined that background absorbance quantification and multiple passaging cycles allow for accurate growth rate measurements even in carbon-poor media, which we used to reveal growth-rate increases during long-term laboratory evolution of Escherichia coli Using mathematical modeling, we showed that maximum growth rate depends on initial cell density. Finally, we demonstrated that growth of Bacillus subtilis with glycerol inhibits the future growth of most of the population, due to lipoteichoic acid synthesis. These studies highlight the challenges of accurate quantification of bacterial growth behaviors.
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Affiliation(s)
- Esha Atolia
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, California, USA
| | - Spencer Cesar
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | - Heidi A Arjes
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Manohary Rajendram
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Benjamin D Knapp
- Biophysics Program, Stanford University School of Medicine, Stanford, California, USA
| | - Somya Khare
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Andrés Aranda-Díaz
- Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Richard E Lenski
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, USA
| | - Kerwyn Casey Huang
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
- Department of Bioengineering, Stanford University, Stanford, California, USA
- Biophysics Program, Stanford University School of Medicine, Stanford, California, USA
- Chan Zuckerberg Biohub, San Francisco, California, USA
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31
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Wang M, Liu Q, Kang X, Zhu Z, Yang H, Xi X, Zhang X, Du Y, Guo M, Tang D, Wang L. Glycogen Metabolism Impairment via Single Gene Mutation in the glgBXCAP Operon Alters the Survival Rate of Escherichia coli Under Various Environmental Stresses. Front Microbiol 2020; 11:588099. [PMID: 33101261 PMCID: PMC7546213 DOI: 10.3389/fmicb.2020.588099] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
Glycogen is a highly branched polysaccharide that is widely present in all life domains. It has been identified in many bacterial species and functions as an important energy storage compound. In addition, it plays important roles in bacterial transmission, pathogenicity, and environmental viability. There are five essential enzymes (coding genes) directly involved in bacterial glycogen metabolism, which forms a single operon glgBXCAP with a suboperonic promoter in glgC gene in Escherichia coli. Currently, there is no comparative study of how the disruptions of the five glycogen metabolism genes influence bacterial phenotypes, such as growth rate, biofilm formation, and environmental survival, etc. In this study, we systematically and comparatively studied five E. coli single-gene mutants (ΔglgC, ΔglgA, ΔglgB, ΔglgP, ΔglgX) in terms of glycogen metabolism and explored their phenotype changes with a focus on environmental stress endurance, such as nutrient deprivation, low temperature, desiccation, and oxidation, etc. Biofilm formation in wild-type and mutant strains was also compared. E. coli wild-type stores the highest glycogen content after around 20-h culture while disruption of degradation genes (glgP, glgX) leads to continuous accumulation of glycogen. However, glycogen primary structure was abnormally changed in ΔglgP and ΔglgX. Meanwhile, increased accumulation of glycogen facilitates the growth of E. coli mutants but reduces glucose consumption in liquid culture and vice versa. Glycogen metabolism disruption also significantly and consistently increases biofilm formation in all the mutants. As for environmental stress endurance, glycogen over-accumulating mutants have enhanced starvation viability and reduced desiccation viability while all mutants showed decreased survival rate at low temperature. No consistent results were found for oxidative stress resistance in terms of glycogen metabolism disruptions, though ΔglgA shows highest resistance toward oxidation with unknown mechanisms. In sum, single gene disruptions in glgBXCAP operon significantly influence bacterial growth and glucose consumption during culture. Accumulation and structure of intracellular glycogen were also significantly altered. In addition, we observed significant changes in E. coli environmental viabilities due to the deletions of certain genes in the operon. Further investigations shall be focused on the molecular mechanisms behind these phenotype changes.
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Affiliation(s)
- Mengmeng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Qinghua Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Xingxing Kang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Zuobin Zhu
- Department of Genetics, School of Life Sciences, Xuzhou Medical University, Xuzhou, China
| | - Huan Yang
- School of Laboratory Medicine, Xuzhou Medical University, Xuzhou, China
| | - Xiangyu Xi
- Xuzhou Infectious Disease Hospital, Xuzhou, China
| | - Xiao Zhang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Yan Du
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Mengzhe Guo
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Daoquan Tang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Pharmaceutical Analysis, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Liang Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China.,Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
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32
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Correlated chromosomal periodicities according to the growth rate and gene expression. Sci Rep 2020; 10:15531. [PMID: 32968121 PMCID: PMC7511328 DOI: 10.1038/s41598-020-72389-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/10/2020] [Indexed: 12/02/2022] Open
Abstract
Linking genetic information to population fitness is crucial to understanding living organisms. Despite the abundant knowledge of the genetic contribution to growth, the overall patterns/features connecting genes, their expression, and growth remain unclear. To reveal the quantitative and direct connections, systematic growth assays of single-gene knockout Escherichia coli strains under both rich and poor nutritional conditions were performed; subsequently, the resultant growth rates were associated with the original expression levels of the knockout genes in the parental genome. Comparative analysis of growth and the transcriptome identified not only the nutritionally differentiated fitness cost genes but also a significant correlation between the growth rates of the single-gene knockout strains and the original expression levels of these knockout genes in the parental strain, regardless of the nutritional variation. In addition, the coordinated chromosomal periodicities of the wild-type transcriptome and the growth rates of the strains lacking the corresponding genes were observed. The common six-period periodicity was somehow attributed to the essential genes, although the underlying mechanism remains to be addressed. The correlated chromosomal periodicities associated with the gene expression-growth dataset were highly valuable for bacterial growth prediction and discovering the working principles governing minimal genetic information.
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33
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Jiang X, Tan WB, Shrivastava R, Seow DCS, Chen SL, Guan XL, Chng SS. Mutations in enterobacterial common antigen biosynthesis restore outer membrane barrier function in Escherichia coli tol-pal mutants. Mol Microbiol 2020; 114:991-1005. [PMID: 32808719 DOI: 10.1111/mmi.14590] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/12/2020] [Indexed: 12/27/2022]
Abstract
The outer membrane (OM) is an essential component of the Gram-negative bacterial envelope that protects the cells against external threats. To maintain a functional OM, cells require distinct mechanisms to ensure balance of proteins and lipids in the membrane. Mutations in OM biogenesis and/or homeostasis pathways often result in permeability defects, but how molecular changes in the OM affect barrier function is unclear. Here, we seek potential mechanism(s) that can alleviate permeability defects in Escherichia coli cells lacking the Tol-Pal complex, which accumulate excess PLs in the OM. We identify mutations in enterobacterial common antigen (ECA) biosynthesis that re-establish OM barrier function against large hydrophilic molecules, yet did not restore lipid homeostasis. Furthermore, we demonstrate that build-up of biosynthetic intermediates, but not loss of ECA itself, contributes to the rescue. This suppression of OM phenotypes is unrelated to known effects that accumulation of ECA intermediates have on the cell wall. Finally, we reveal that an unusual diacylglycerol pyrophosphoryl-linked lipid species also accumulates in ECA mutants, and might play a role in the rescue phenotype. Our work provides insights into how OM barrier function can be restored independent of lipid homeostasis, and highlights previously unappreciated effects of ECA-related species in OM biology.
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Affiliation(s)
- Xiang'Er Jiang
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Wee Boon Tan
- Singapore Center for Environmental Life Sciences Engineering, National University of Singapore (SCELSE-NUS), Singapore, Singapore
| | - Rahul Shrivastava
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Deborah Chwee San Seow
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Swaine Lin Chen
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Genome Institute of Singapore, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Xue Li Guan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore, Singapore.,Singapore Center for Environmental Life Sciences Engineering, National University of Singapore (SCELSE-NUS), Singapore, Singapore
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34
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Nagai M, Kurokawa M, Ying BW. The highly conserved chromosomal periodicity of transcriptomes and the correlation of its amplitude with the growth rate in Escherichia coli. DNA Res 2020; 27:5899727. [PMID: 32866232 PMCID: PMC7508348 DOI: 10.1093/dnares/dsaa018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 08/24/2020] [Indexed: 11/12/2022] Open
Abstract
The growth rate, representing the fitness of a bacterial population, is determined by the transcriptome. Chromosomal periodicity, which is known as the periodic spatial pattern of a preferred chromosomal distance in microbial genomes, is a representative overall feature of the transcriptome; however, whether and how it is associated with the bacterial growth rate are unknown. To address these questions, we analysed a total of 213 transcriptomes of multiple Escherichia coli strains growing in an assortment of culture conditions varying in terms of temperature, nutrition level and osmotic pressure. Intriguingly, Fourier transform analyses of the transcriptome identified a common chromosomal periodicity of transcriptomes, which was independent of the variation in genomes and environments. In addition, fitting of the data to a theoretical model, we found that the amplitudes of the periodic transcriptomes were significantly correlated with the growth rates. These results indicated that the amplitude of periodic transcriptomes is a parameter representing the global pattern of gene expression in correlation with the bacterial growth rate. Thus, our study provides a novel parameter for evaluating the adaptiveness of a growing bacterial population and quantitatively predicting the growth dynamics according to the global expression pattern.
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Affiliation(s)
- Motoki Nagai
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Masaomi Kurokawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
| | - Bei-Wen Ying
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8572, Japan
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35
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Abstract
Selection of mutants in a microbial population depends on multiple cellular traits. In serial-dilution evolution experiments, three key traits are the lag time when transitioning from starvation to growth, the exponential growth rate, and the yield (number of cells per unit resource). Here, we investigate how these traits evolve in laboratory evolution experiments using a minimal model of population dynamics, where the only interaction between cells is competition for a single limiting resource. We find that the fixation probability of a beneficial mutation depends on a linear combination of its growth rate and lag time relative to its immediate ancestor, even under clonal interference. The relative selective pressure on growth rate and lag time is set by the dilution factor; a larger dilution factor favors the adaptation of growth rate over the adaptation of lag time. The model shows that yield, however, is under no direct selection. We also show how the adaptation speeds of growth and lag depend on experimental parameters and the underlying supply of mutations. Finally, we investigate the evolution of covariation between these traits across populations, which reveals that the population growth rate and lag time can evolve a nonzero correlation even if mutations have uncorrelated effects on the two traits. Altogether these results provide useful guidance to future experiments on microbial evolution.
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36
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Hartmann R, Teeseling MCF, Thanbichler M, Drescher K. BacStalk: A comprehensive and interactive image analysis software tool for bacterial cell biology. Mol Microbiol 2020; 114:140-150. [DOI: 10.1111/mmi.14501] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 03/16/2020] [Indexed: 01/28/2023]
Affiliation(s)
- Raimo Hartmann
- Max Planck Institute for Terrestrial Microbiology Marburg Germany
| | | | - Martin Thanbichler
- Max Planck Institute for Terrestrial Microbiology Marburg Germany
- Department of Biology Philipps‐Universität Marburg Germany
- LOEWE Center for Synthetic Microbiology Marburg Germany
| | - Knut Drescher
- Max Planck Institute for Terrestrial Microbiology Marburg Germany
- LOEWE Center for Synthetic Microbiology Marburg Germany
- Department of Physics Philipps‐Universität Marburg Germany
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37
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Gray WT, Govers SK, Xiang Y, Parry BR, Campos M, Kim S, Jacobs-Wagner C. Nucleoid Size Scaling and Intracellular Organization of Translation across Bacteria. Cell 2020; 177:1632-1648.e20. [PMID: 31150626 DOI: 10.1016/j.cell.2019.05.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 04/01/2019] [Accepted: 05/08/2019] [Indexed: 01/10/2023]
Abstract
The scaling of organelles with cell size is thought to be exclusive to eukaryotes. Here, we demonstrate that similar scaling relationships hold for the bacterial nucleoid. Despite the absence of a nuclear membrane, nucleoid size strongly correlates with cell size, independent of changes in DNA amount and across various nutrient conditions. This correlation is observed in diverse bacteria, revealing a near-constant ratio between nucleoid and cell size for a given species. As in eukaryotes, the nucleocytoplasmic ratio in bacteria varies greatly among species. This spectrum of nucleocytoplasmic ratios is independent of genome size, and instead it appears linked to the average population cell size. Bacteria with different nucleocytoplasmic ratios have a cytoplasm with different biophysical properties, impacting ribosome mobility and localization. Together, our findings identify new organizational principles and biophysical features of bacterial cells, implicating the nucleocytoplasmic ratio and cell size as determinants of the intracellular organization of translation.
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Affiliation(s)
- William T Gray
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Sander K Govers
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Yingjie Xiang
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, USA
| | - Bradley R Parry
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Manuel Campos
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Sangjin Kim
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, USA
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale University, West Haven, CT, USA; Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA.
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38
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pH-dependent activation of cytokinesis modulates Escherichia coli cell size. PLoS Genet 2020; 16:e1008685. [PMID: 32203516 PMCID: PMC7117782 DOI: 10.1371/journal.pgen.1008685] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 04/02/2020] [Accepted: 02/19/2020] [Indexed: 01/21/2023] Open
Abstract
Cell size is a complex trait, derived from both genetic and environmental factors. Environmental determinants of bacterial cell size identified to date primarily target assembly of cytosolic components of the cell division machinery. Whether certain environmental cues also impact cell size through changes in the assembly or activity of extracytoplasmic division proteins remains an open question. Here, we identify extracellular pH as a modulator of cell division and a significant determinant of cell size across evolutionarily distant bacterial species. In the Gram-negative model organism Escherichia coli, our data indicate environmental pH impacts the length at which cells divide by altering the ability of the terminal cell division protein FtsN to localize to the cytokinetic ring where it activates division. Acidic environments lead to enrichment of FtsN at the septum and activation of division at a reduced cell length. Alkaline pH inhibits FtsN localization and suppresses division activation. Altogether, our work reveals a previously unappreciated role for pH in bacterial cell size control. Bacteria are constantly under assault from endogenous and environmental stressors. To ensure viability and reproductive fitness, many bacteria alter their growth and replication in response to stressful conditions. Previous work from many groups has identified regulatory mechanisms linking cell division with nutrient availability and metabolic state. However, comparatively little is known about how the cell division machinery responds to physical and chemical cues in the environment. Here, we identify a fundamental property of the extracellular environment—environmental pH—as a significant contributor to bacterial cell size. Our genetic and cytological data indicate pH-dependent changes in E. coli cell size are in part due to differential localization of the cell division activator FtsN across pH environments. Increased abundance of FtsN at midcell in acidic environments promotes cell division at a reduced cell volume, while decreased abundance of FtsN at midcell in alkaline environments effectively delays cell division until a larger size is reached. Altogether, our work identifies pH as an environmental determinant of E. coli cell division and illuminates FtsN recruitment as a mediator of cell size.
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39
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Negri A, Jąkalski M, Szczuka A, Pryszcz LP, Mruk I. Transcriptome analyses of cells carrying the Type II Csp231I restriction-modification system reveal cross-talk between two unrelated transcription factors: C protein and the Rac prophage repressor. Nucleic Acids Res 2019; 47:9542-9556. [PMID: 31372643 PMCID: PMC6765115 DOI: 10.1093/nar/gkz665] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 07/16/2019] [Accepted: 07/23/2019] [Indexed: 12/27/2022] Open
Abstract
Restriction-modification (R–M) systems represent an effective mechanism of defence against invading bacteriophages, and are widely spread among bacteria and archaea. In acquiring a Type II R–M system via horizontal gene transfer, the new hosts become more resistant to phage infection, through the action of a restriction endonuclease (REase), which recognizes and cleaves specific target DNAs. To protect the host cell's DNA, there is also a methyltransferase (MTase), which prevents DNA cleavage by the cognate REase. In some R–M systems, the host also accepts a cis-acting transcription factor (C protein), which regulates the counteracting activities of REase and MTase to avoid host self-restriction. Our study characterized the unexpected phenotype of Escherichia coli cells, which manifested as extensive cell filamentation triggered by acquiring the Csp231I R–M system from Citrobacter sp. Surprisingly, we found that the cell morphology defect was solely dependent on the C regulator. Our transcriptome analysis supported by in vivo and in vitro assays showed that C protein directly silenced the expression of the RacR repressor to affect the Rac prophage-related genes. The rac locus ydaST genes, when derepressed, exerted a toxicity indicated by cell filamentation through an unknown mechanism. These results provide an apparent example of transcription factor cross-talk, which can have significant consequences for the host, and may represent a constraint on lateral gene transfer.
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Affiliation(s)
- Alessandro Negri
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Marcin Jąkalski
- Department of Plant Taxonomy and Nature Conservation, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Aleksandra Szczuka
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
| | - Leszek P Pryszcz
- Laboratory of Zebrafish Developmental Genomics, International Institute of Molecular and Cell Biology, Warsaw, ul. Trojdena 4, 02-109 Warsaw, Poland
| | - Iwona Mruk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, Gdansk 80-308, Poland
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40
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Ojkic N, Serbanescu D, Banerjee S. Surface-to-volume scaling and aspect ratio preservation in rod-shaped bacteria. eLife 2019; 8:47033. [PMID: 31456563 PMCID: PMC6742476 DOI: 10.7554/elife.47033] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 08/28/2019] [Indexed: 01/16/2023] Open
Abstract
Rod-shaped bacterial cells can readily adapt their lengths and widths in response to environmental changes. While many recent studies have focused on the mechanisms underlying bacterial cell size control, it remains largely unknown how the coupling between cell length and width results in robust control of rod-like bacterial shapes. In this study we uncover a conserved surface-to-volume scaling relation in Escherichia coli and other rod-shaped bacteria, resulting from the preservation of cell aspect ratio. To explain the mechanistic origin of aspect-ratio control, we propose a quantitative model for the coupling between bacterial cell elongation and the accumulation of an essential division protein, FtsZ. This model reveals a mechanism for why bacterial aspect ratio is independent of cell size and growth conditions, and predicts cell morphological changes in response to nutrient perturbations, antibiotics, MreB or FtsZ depletion, in quantitative agreement with experimental data.
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Affiliation(s)
- Nikola Ojkic
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Diana Serbanescu
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, London, United Kingdom
| | - Shiladitya Banerjee
- Department of Physics and Astronomy, Institute for the Physics of Living Systems, University College London, London, United Kingdom
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41
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Zaritsky A, Vollmer W, Männik J, Liu C. Does the Nucleoid Determine Cell Dimensions in Escherichia coli? Front Microbiol 2019; 10:1717. [PMID: 31447799 PMCID: PMC6691162 DOI: 10.3389/fmicb.2019.01717] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/11/2019] [Indexed: 11/13/2022] Open
Abstract
Bacillary, Gram-negative bacteria grow by elongation with no discernible change in width, but during faster growth in richer media the cells are also wider. The mechanism regulating the change in cell width W during transitions from slow to fast growth is a fundamental, unanswered question in molecular biology. The value of W that changes in the divisome and during the division process only, is related to the nucleoid complexity, determined by the rates of growth and of chromosome replication; the former is manipulated by nutritional conditions and the latter-by thymine limitation of thyA mutants. Such spatio-temporal regulation is supported by existence of a minimal possible distance between successive replisomes, so-called eclipse that limits the number of replisomes to a maximum. Breaching this limit by slowing replication in fast growing cells results in maximal nucleoid complexity that is associated with maximum cell width, supporting the notion of Nucleoid-to-Divisome signal transmission. Physical signal(s) may be delivered from the nucleoid to assemble the divisome and to fix the value of W in the nascent cell pole.
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Affiliation(s)
- Arieh Zaritsky
- Faculty of Natural Sciences, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jaan Männik
- Department of Physics & Astronomy, The University of Tennessee, Knoxville, Knoxville, TN, United States
| | - Chenli Liu
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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42
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Zahir T, Camacho R, Vitale R, Ruckebusch C, Hofkens J, Fauvart M, Michiels J. High-throughput time-resolved morphology screening in bacteria reveals phenotypic responses to antibiotics. Commun Biol 2019; 2:269. [PMID: 31341968 PMCID: PMC6650389 DOI: 10.1038/s42003-019-0480-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 05/21/2019] [Indexed: 11/09/2022] Open
Abstract
Image-based high-throughput screening strategies for quantifying morphological phenotypes have proven widely successful. Here we describe a combined experimental and multivariate image analysis approach for systematic large-scale phenotyping of morphological dynamics in bacteria. Using off-the-shelf components and software, we established a workflow for high-throughput time-resolved microscopy. We then screened the single-gene deletion collection of Escherichia coli for antibiotic-induced morphological changes. Using single-cell quantitative descriptors and supervised classification methods, we measured how different cell morphologies developed over time for all strains in response to the β-lactam antibiotic cefsulodin. 191 strains exhibit significant variations under antibiotic treatment. Phenotypic clustering provided insights into processes that alter the antibiotic response. Mutants with stable bulges show delayed lysis, contributing to antibiotic tolerance. Lipopolysaccharides play a crucial role in bulge stability. This study demonstrates how multiparametric phenotyping by high-throughput time-resolved imaging and computer-aided cell classification can be used for comprehensively studying dynamic morphological transitions in bacteria.
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Affiliation(s)
- Taiyeb Zahir
- Centre of Microbial and Plant Genetics, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- VIB-KU Leuven Center of Microbiology, Leuven, 3001 Belgium
| | - Rafael Camacho
- Department of Chemistry, KU Leuven—University of Leuven, Leuven, 3001 Belgium
| | - Raffaele Vitale
- Department of Chemistry, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- LASIR CNRS, Université de Lille, Lille, F-59000 France
| | | | - Johan Hofkens
- Department of Chemistry, KU Leuven—University of Leuven, Leuven, 3001 Belgium
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- VIB-KU Leuven Center of Microbiology, Leuven, 3001 Belgium
- imec, Leuven, 3001 Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven—University of Leuven, Leuven, 3001 Belgium
- VIB-KU Leuven Center of Microbiology, Leuven, 3001 Belgium
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43
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Reyes-Lamothe R, Sherratt DJ. The bacterial cell cycle, chromosome inheritance and cell growth. Nat Rev Microbiol 2019; 17:467-478. [DOI: 10.1038/s41579-019-0212-7] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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44
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Predicting the decision making chemicals used for bacterial growth. Sci Rep 2019; 9:7251. [PMID: 31076576 PMCID: PMC6510730 DOI: 10.1038/s41598-019-43587-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 04/24/2019] [Indexed: 01/01/2023] Open
Abstract
Predicting the contribution of media components to bacterial growth was first initiated by introducing machine learning to high-throughput growth assays. A total of 1336 temporal growth records corresponding to 225 different media, which were composed of 13 chemical components, were generated. The growth rate and saturated density of each growth curve were automatically calculated with the newly developed data processing program. To identify the decision making factors related to growth among the 13 chemicals, big datasets linking the growth parameters to the chemical combinations were subjected to decision tree learning. The results showed that the only carbon source, glucose, determined bacterial growth, but it was not the first priority. Instead, the top decision making chemicals in relation to the growth rate and saturated density were ammonium and ferric ions, respectively. Three chemical components (NH4+, Mg2+ and glucose) commonly appeared in the decision trees of the growth rate and saturated density, but they exhibited different mechanisms. The concentration ranges for fast growth and high density were overlapped for glucose but distinguished for NH4+ and Mg2+. The results suggested that these chemicals were crucial in determining the growth speed and growth maximum in either a universal use or a trade-off manner. This differentiation might reflect the diversity in the resource allocation mechanisms for growth priority depending on the environmental restrictions. This study provides a representative example for clarifying the contribution of the environment to population dynamics through an innovative viewpoint of employing modern data science within traditional microbiology to obtain novel findings.
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45
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Levin PA, Taheri-Araghi S. One is Nothing without the Other: Theoretical and Empirical Analysis of Cell Growth and Cell Cycle Progression. J Mol Biol 2019; 431:2061-2067. [PMID: 31026450 DOI: 10.1016/j.jmb.2019.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/25/2019] [Accepted: 04/02/2019] [Indexed: 11/19/2022]
Abstract
Small, fast-growing bacteria make ideal subjects for genetic and quantitative analysis alike. Long the darling of theoreticians, efforts to understand the relationship between cell growth and cell cycle progression in bacterial systems have been propelled by modelers and empiricist in equal measure. Taking a historical approach, here we break down early work in this area, the impact it had on how the bacterial cell cycle is understood and interrogated, and changes brought by the advent of high-throughput techniques for the analysis of individual bacterial cells in culture.
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Affiliation(s)
- Petra Anne Levin
- Department of Biology, Washington University in St. Louis, MO 63130, United States.
| | - Sattar Taheri-Araghi
- Department of Physics and Astronomy, California State University, Northridge, CA 91311, United States.
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46
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Campos M, Govers SK, Irnov I, Dobihal GS, Cornet F, Jacobs-Wagner C. Genomewide phenotypic analysis of growth, cell morphogenesis, and cell cycle events in Escherichia coli. Mol Syst Biol 2018; 14:e7573. [PMID: 29941428 PMCID: PMC6018989 DOI: 10.15252/msb.20177573] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cell size, cell growth, and cell cycle events are necessarily intertwined to achieve robust bacterial replication. Yet, a comprehensive and integrated view of these fundamental processes is lacking. Here, we describe an image‐based quantitative screen of the single‐gene knockout collection of Escherichia coli and identify many new genes involved in cell morphogenesis, population growth, nucleoid (bulk chromosome) dynamics, and cell division. Functional analyses, together with high‐dimensional classification, unveil new associations of morphological and cell cycle phenotypes with specific functions and pathways. Additionally, correlation analysis across ~4,000 genetic perturbations shows that growth rate is surprisingly not predictive of cell size. Growth rate was also uncorrelated with the relative timings of nucleoid separation and cell constriction. Rather, our analysis identifies scaling relationships between cell size and nucleoid size and between nucleoid size and the relative timings of nucleoid separation and cell division. These connections suggest that the nucleoid links cell morphogenesis to the cell cycle.
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Affiliation(s)
- Manuel Campos
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.,Laboratoire de Microbiologie et Génétique Moléculaires (LMGM; UMR5100), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, UPS, Toulouse, France
| | - Sander K Govers
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Irnov Irnov
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Genevieve S Dobihal
- Microbial Sciences Institute, Yale University, West Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
| | - François Cornet
- Laboratoire de Microbiologie et Génétique Moléculaires (LMGM; UMR5100), Centre de Biologie Intégrative (CBI), Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, UPS, Toulouse, France
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale University, West Haven, CT, USA .,Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University, New Haven, CT, USA.,Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, USA
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47
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Ectopic Expression of the ydaS and ydaT Genes of the Cryptic Prophage Rac of Escherichia coli K-12 May Be Toxic but Do They Really Encode Toxins?: a Case for Using Genetic Context To Understand Function. mSphere 2018; 3:3/2/e00163-18. [PMID: 29695625 PMCID: PMC5917428 DOI: 10.1128/msphere.00163-18] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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48
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Westfall CS, Levin PA. Comprehensive analysis of central carbon metabolism illuminates connections between nutrient availability, growth rate, and cell morphology in Escherichia coli. PLoS Genet 2018; 14:e1007205. [PMID: 29432413 PMCID: PMC5825171 DOI: 10.1371/journal.pgen.1007205] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 02/23/2018] [Accepted: 01/17/2018] [Indexed: 01/23/2023] Open
Abstract
Bacterial morphology is a complex trait that is highly sensitive to changes in the environment. For heterotrophic organisms, such as Escherichia coli, increases in nutrient levels are frequently accompanied by several-fold increases in both size and growth rate. Despite the dramatic nature of these changes, how alterations in nutrient availability translate into changes in growth and morphology remains a largely open question. To understand the signaling networks coupling nutrient availability with size and shape, we examined the impact of deletions in the entirety of non-essential central carbon metabolic genes on E. coli growth rate and cell size. Our data reveal the presence of multiple metabolic nodes that play important yet distinctive roles in dictating biosynthetic capacity and shaping cell morphology. Specifically, perturbations of acetyl-CoA metabolism impact cell size and division through changes in fatty acid synthesis. Additionally, we identify a genetic pathway linking glucose levels to cell width through the signaling molecule cyclic-AMP. Together our findings highlight a surprising diversity of factors and mechanisms contributing to growth potential and cell morphology, providing a foundation for further studies. Often taken for granted, the shape of bacterial cells is a complex trait that is highly sensitive to environmental perturbations. Nutrients in particular, strongly impact bacterial morphology together with growth rate. The ubiquitous, rod-shaped bacteria Escherichia coli increases both length and width several fold upon a shift from nutrient poor to nutrient rich medium, a change accompanied by an equally dramatic increase in growth rate. Central carbon metabolism is an obvious site for the integration of nutrient dependent signals that dictate cell size and shape. To develop a clearer picture of the molecular mechanisms coupling nutrient assimilation with cell growth and morphology, we screened the entirety of non-essential carbon metabolic genes for their contribution to growth rate and cell shape. Our data reveal the presence of multiple regulatory circuits coordinating different metabolic pathways with specific aspects of cell growth and morphology. Together, these data firmly establish a role for central carbon metabolism as an environmentally sensitive sculptor of bacterial cells.
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Affiliation(s)
- Corey S. Westfall
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
| | - Petra Anne Levin
- Department of Biology, Washington University, St. Louis, Missouri, United States of America
- * E-mail:
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49
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Repression of YdaS Toxin Is Mediated by Transcriptional Repressor RacR in the Cryptic rac Prophage of Escherichia coli K-12. mSphere 2017; 2:mSphere00392-17. [PMID: 29205228 PMCID: PMC5700373 DOI: 10.1128/msphere.00392-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 09/15/2017] [Indexed: 11/29/2022] Open
Abstract
Transcription factors in the bacterium E. coli are rarely essential, and when they are essential, they are largely toxin-antitoxin systems. While studying transcription factors encoded in horizontally acquired regions in E. coli, we realized that the protein RacR, a putative transcription factor encoded by a gene on the rac prophage, is an essential protein. Here, using genetics, biochemistry, and bioinformatics, we show that its essentiality derives from its role as a transcriptional repressor of the ydaS and ydaT genes, whose products are toxic to the cell. Unlike type II toxin-antitoxin systems in which transcriptional regulation involves complexes of the toxin and antitoxin, repression by RacR is sufficient to keep ydaS transcriptionally silent. Horizontal gene transfer is a major driving force behind the genomic diversity seen in prokaryotes. The cryptic rac prophage in Escherichia coli K-12 carries the gene for a putative transcription factor RacR, whose deletion is lethal. We have shown that the essentiality of racR in E. coli K-12 is attributed to its role in transcriptionally repressing toxin gene(s) called ydaS and ydaT, which are adjacent to and coded divergently to racR. IMPORTANCE Transcription factors in the bacterium E. coli are rarely essential, and when they are essential, they are largely toxin-antitoxin systems. While studying transcription factors encoded in horizontally acquired regions in E. coli, we realized that the protein RacR, a putative transcription factor encoded by a gene on the rac prophage, is an essential protein. Here, using genetics, biochemistry, and bioinformatics, we show that its essentiality derives from its role as a transcriptional repressor of the ydaS and ydaT genes, whose products are toxic to the cell. Unlike type II toxin-antitoxin systems in which transcriptional regulation involves complexes of the toxin and antitoxin, repression by RacR is sufficient to keep ydaS transcriptionally silent.
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50
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Irnov I, Wang Z, Jannetty ND, Bustamante JA, Rhee KY, Jacobs-Wagner C. Crosstalk between the tricarboxylic acid cycle and peptidoglycan synthesis in Caulobacter crescentus through the homeostatic control of α-ketoglutarate. PLoS Genet 2017; 13:e1006978. [PMID: 28827812 PMCID: PMC5578688 DOI: 10.1371/journal.pgen.1006978] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/31/2017] [Accepted: 08/15/2017] [Indexed: 11/18/2022] Open
Abstract
To achieve robust replication, bacteria must integrate cellular metabolism and cell wall growth. While these two processes have been well characterized, the nature and extent of cross-regulation between them is not well understood. Here, using classical genetics, CRISPRi, metabolomics, transcriptomics and chemical complementation approaches, we show that a loss of the master regulator Hfq in Caulobacter crescentus alters central metabolism and results in cell shape defects in a nutrient-dependent manner. We demonstrate that the cell morphology phenotype in the hfq deletion mutant is attributable to a disruption of α-ketoglutarate (KG) homeostasis. In addition to serving as a key intermediate of the tricarboxylic acid (TCA) cycle, KG is a by-product of an enzymatic reaction required for the synthesis of peptidoglycan, a major component of the bacterial cell wall. Accumulation of KG in the hfq deletion mutant interferes with peptidoglycan synthesis, resulting in cell morphology defects and increased susceptibility to peptidoglycan-targeting antibiotics. This work thus reveals a direct crosstalk between the TCA cycle and cell wall morphogenesis. This crosstalk highlights the importance of metabolic homeostasis in not only ensuring adequate availability of biosynthetic precursors, but also in preventing interference with cellular processes in which these intermediates arise as by-products.
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Affiliation(s)
- Irnov Irnov
- Microbial Sciences Institute, Yale University, West Haven, CT, United States of America
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, United States of America
| | - Zhe Wang
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, United States of America
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medical College, New York, NY, United States of America
| | - Nicholas D. Jannetty
- Microbial Sciences Institute, Yale University, West Haven, CT, United States of America
- Howard Hughes Medical Institute, Yale University, New Haven, CT, United States of America
| | - Julian A. Bustamante
- Howard Hughes Medical Institute, Yale University, New Haven, CT, United States of America
| | - Kyu Y. Rhee
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, United States of America
- Division of Infectious Diseases, Department of Medicine, Weill Cornell Medical College, New York, NY, United States of America
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale University, West Haven, CT, United States of America
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, United States of America
- Howard Hughes Medical Institute, Yale University, New Haven, CT, United States of America
- Department of Microbial Pathogenesis, Yale School of Medicine, Yale University, New Haven, CT, United States of America
- * E-mail:
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