1
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Hallgren J, Jonas K. Nutritional control of bacterial DNA replication. Curr Opin Microbiol 2024; 77:102403. [PMID: 38035509 DOI: 10.1016/j.mib.2023.102403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/30/2023] [Accepted: 11/01/2023] [Indexed: 12/02/2023]
Abstract
All cells must ensure precise regulation of DNA replication initiation in coordination with growth rate and in response to nutrient availability. According to a long-standing model, DNA replication initiation is tightly coupled to cell mass increase in bacteria. Despite controversies regarding this model, recent studies have provided additional support of this idea. The exact molecular mechanisms linking cell growth with DNA replication under different nutrient conditions remain elusive. However, recent studies in Caulobacter crescentus and Escherichia coli have provided insights into the regulation of DNA replication initiation in response to starvation. These mechanisms include the starvation-dependent regulation of DnaA abundance as well as mechanisms involving the small signaling molecule (p)ppGpp. In this review, we discuss these mechanisms in the context of previous findings. We highlight species-dependent similarities and differences and consider the precise growth conditions, in which the different mechanisms are active.
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Affiliation(s)
- Joel Hallgren
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory, Stockholm University, 106 91 Stockholm, Sweden
| | - Kristina Jonas
- Department of Molecular Biosciences, The Wenner-Gren Institute, Science for Life Laboratory, Stockholm University, 106 91 Stockholm, Sweden.
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2
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Chen X, He C, Zhang Q, Bayakmetov S, Wang X. Modularized Design and Construction of Tunable Microbial Consortia with Flexible Topologies. ACS Synth Biol 2024; 13:183-194. [PMID: 38166159 PMCID: PMC10805104 DOI: 10.1021/acssynbio.3c00420] [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: 07/12/2023] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 01/04/2024]
Abstract
Complex and fluid bacterial community compositions are critical to diversity, stability, and function. However, quantitative and mechanistic descriptions of the dynamics of such compositions are still lacking. Here, we develop a modularized design framework that allows for bottom-up construction and the study of synthetic bacterial consortia with different topologies. We showcase the microbial consortia design and building process by constructing amensalism and competition consortia using only genetic circuit modules to engineer different strains to form the community. Functions of modules and hosting strains are validated and quantified to calibrate dynamic parameters, which are then directly fed into a full mechanistic model to accurately predict consortia composition dynamics for both amensalism and competition without further fitting. More importantly, such quantitative understanding successfully identifies the experimental conditions to achieve coexistence composition dynamics. These results illustrate the process of both computationally and experimentally building up bacteria consortia complexity and hence achieve robust control of such fluid systems.
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Affiliation(s)
- Xingwen Chen
- School
of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Changhan He
- Department
of Mathematics, University of California
Irvine, Irvine, California 92697, United States
| | - Qi Zhang
- School
of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Samat Bayakmetov
- School
of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
| | - Xiao Wang
- School
of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85287, United States
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3
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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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4
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Vo L, Avgidis F, Mattingly HH, Balasubramanian R, Shimizu TS, Kazmierczak BI, Emonet T. Non-genetic adaptation by collective migration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.02.573956. [PMID: 38260286 PMCID: PMC10802332 DOI: 10.1101/2024.01.02.573956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Collective behaviors require coordination of individuals. Thus, a population must adjust its phenotypic distribution to adapt to changing environments. How can a population regulate its phenotypic distribution? One strategy is to utilize specialized networks for gene regulation and maintaining distinct phenotypic subsets. Another involves genetic mutations, which can be augmented by stress-response pathways. Here, we studied how a migrating bacterial population regulates its phenotypic distribution to traverse across diverse environments. We generated isogenic Escherichia coli populations with varying distributions of swimming behaviors and observed their phenotype distributions during migration in liquid and porous environments. Surprisingly, we found that during collective migration, the distributions of swimming phenotypes adapt to the environment without mutations or gene regulation. Instead, adaptation is caused by the dynamic and reversible enrichment of high-performing swimming phenotypes within each environment. This adaptation mechanism is supported by a recent theoretical study, which proposed that the phenotypic composition of a migrating population results from a balance between cell growth generating diversity and collective migration eliminating the phenotypes that are unable to keep up with the migrating group. Furthermore, by examining chemoreceptor abundance distributions during migration towards different attractants, we found that this mechanism acts on multiple chemotaxis-related traits simultaneously. Our findings reveal that collective migration itself can enable cell populations with continuous, multi-dimensional phenotypes to flexibly and rapidly adapt their phenotypic composition to diverse environmental conditions. Significance statement Conventional cell adaptation mechanisms, like gene regulation and random phenotypic switching, act swiftly but are limited to a few traits, while mutation-driven adaptations unfold slowly. By quantifying phenotypic diversity during bacterial collective migration, we discovered an adaptation mechanism that rapidly and reversibly adjusts multiple traits simultaneously. By dynamically balancing the elimination of phenotypes unable to keep pace with generation of diversity through growth, this process enables populations to tune their phenotypic composition based on the environment, without the need for gene regulation or mutations. Given the prevalence of collective migration in microbes, cancers, and embryonic development, non-genetic adaptation through collective migration may be a universal mechanism for populations to navigate diverse environments, offering insights into broader applications across various fields.
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5
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Vashistha H, Jammal-Touma J, Singh K, Rabin Y, Salman H. Bacterial cell-size changes resulting from altering the relative expression of Min proteins. Nat Commun 2023; 14:5710. [PMID: 37714867 PMCID: PMC10504268 DOI: 10.1038/s41467-023-41487-0] [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: 10/14/2022] [Accepted: 09/06/2023] [Indexed: 09/17/2023] Open
Abstract
The timing of cell division, and thus cell size in bacteria, is determined in part by the accumulation dynamics of the protein FtsZ, which forms the septal ring. FtsZ localization depends on membrane-associated Min proteins, which inhibit FtsZ binding to the cell pole membrane. Changes in the relative concentrations of Min proteins can disrupt FtsZ binding to the membrane, which in turn can delay cell division until a certain cell size is reached, in which the dynamics of Min proteins frees the cell membrane long enough to allow FtsZ ring formation. Here, we study the effect of Min proteins relative expression on the dynamics of FtsZ ring formation and cell size in individual Escherichia coli bacteria. Upon inducing overexpression of minE, cell size increases gradually to a new steady-state value. Concurrently, the time required to initiate FtsZ ring formation grows as the size approaches the new steady-state, at which point the ring formation initiates as early as before induction. These results highlight the contribution of Min proteins to cell size control, which may be partially responsible for the size fluctuations observed in bacterial populations, and may clarify how the size difference acquired during asymmetric cell division is offset.
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Affiliation(s)
- Harsh Vashistha
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Joanna Jammal-Touma
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kulveer Singh
- Department of Physics and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Yitzhak Rabin
- Department of Physics and Institute for Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel
| | - Hanna Salman
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA, USA.
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6
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Chen KN, Ma BG. OptoCRISPRi-HD: Engineering a Bacterial Green-Light-Activated CRISPRi System with a High Dynamic Range. ACS Synth Biol 2023; 12:1708-1715. [PMID: 37217315 DOI: 10.1021/acssynbio.3c00035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The ability to modulate gene expression is crucial for studying gene function and programming cell behaviors. Combining the reliability of CRISPRi and the precision of optogenetics, the optoCRISPRi technique is emerging as an advanced tool for live-cell gene regulation. Since previous versions of optoCRISPRi often exhibit no more than a 10-fold dynamic range due to the leakage activity, they are not suitable for targets that are sensitive to such leakage or critical for cell growth. Here, we describe a green-light-activated CRISPRi system with a high dynamic range (40 fold) and the flexibility of changing targets in Escherichia coli. Our optoCRISPRi-HD system can efficiently repress essential genes, nonessential genes, or inhibit the initiation of DNA replication. Providing a regulative system with high resolution over space-time and extensive targets, our study would facilitate further research involving complex gene networks, metabolic flux redirection, or bioprinting.
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Affiliation(s)
- Ke-Ning Chen
- 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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7
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Cao Q, Huang W, Zhang Z, Chu P, Wei T, Zheng H, Liu C. The Quantification of Bacterial Cell Size: Discrepancies Arise from Varied Quantification Methods. Life (Basel) 2023; 13:1246. [PMID: 37374027 DOI: 10.3390/life13061246] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/21/2023] [Accepted: 05/21/2023] [Indexed: 06/29/2023] Open
Abstract
The robust regulation of the cell cycle is critical for the survival and proliferation of bacteria. To gain a comprehensive understanding of the mechanisms regulating the bacterial cell cycle, it is essential to accurately quantify cell-cycle-related parameters and to uncover quantitative relationships. In this paper, we demonstrate that the quantification of cell size parameters using microscopic images can be influenced by software and by the parameter settings used. Remarkably, even if the consistent use of a particular software and specific parameter settings is maintained throughout a study, the type of software and the parameter settings can significantly impact the validation of quantitative relationships, such as the constant-initiation-mass hypothesis. Given these inherent characteristics of microscopic image-based quantification methods, it is recommended that conclusions be cross-validated using independent methods, especially when the conclusions are associated with cell size parameters that were obtained under different conditions. To this end, we presented a flexible workflow for simultaneously quantifying multiple bacterial cell-cycle-related parameters using microscope-independent methods.
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Affiliation(s)
- Qian'andong Cao
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenqi Huang
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zheng Zhang
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Pan Chu
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ting Wei
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hai Zheng
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chenli Liu
- Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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8
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Helmstetter CE. Fifty-Five Years of Research on B, C and D in Escherichia coli. Life (Basel) 2023; 13:life13040977. [PMID: 37109506 PMCID: PMC10141973 DOI: 10.3390/life13040977] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 03/31/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
The basic properties of the Escherichia coli duplication process can be defined by two time periods: C, the time for a round of chromosome replication, and D, the time between the end of a round of replication and cell division. Given the durations of these periods, the pattern of chromosome replication during the cell cycle can be determined for cells growing with any doubling time. In the 55 years since these parameters were identified, there have been numerous investigations into their durations and into the elements that determine their initiations. In this review, I discuss the history of our involvement in these studies from the very beginning, some of what has been learned over the years by measuring the durations of C and D, and what might be learned with additional investigations.
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Affiliation(s)
- Charles E Helmstetter
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA
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9
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Kar P, Tiruvadi-Krishnan S, Männik J, Männik J, Amir A. Using conditional independence tests to elucidate causal links in cell cycle regulation in Escherichia coli. Proc Natl Acad Sci U S A 2023; 120:e2214796120. [PMID: 36897981 PMCID: PMC10089181 DOI: 10.1073/pnas.2214796120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/09/2023] [Indexed: 03/12/2023] Open
Abstract
How cells regulate their cell cycles is a central question for cell biology. Models of cell size homeostasis have been proposed for bacteria, archaea, yeast, plant, and mammalian cells. New experiments bring forth high volumes of data suitable for testing existing models of cell size regulation and proposing new mechanisms. In this paper, we use conditional independence tests in conjunction with data of cell size at key cell cycle events (birth, initiation of DNA replication, and constriction) in the model bacterium Escherichia coli to select between the competing cell cycle models. We find that in all growth conditions that we study, the division event is controlled by the onset of constriction at midcell. In slow growth, we corroborate a model where replication-related processes control the onset of constriction at midcell. In faster growth, we find that the onset of constriction is affected by additional cues beyond DNA replication. Finally, we also find evidence for the presence of additional cues triggering initiations of DNA replication apart from the conventional notion where the mother cells solely determine the initiation event in the daughter cells via an adder per origin model. The use of conditional independence tests is a different approach in the context of understanding cell cycle regulation and it can be used in future studies to further explore the causal links between cell events.
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Affiliation(s)
- Prathitha Kar
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02134
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA02138
| | | | - Jaana Männik
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN37996
| | - Jaan Männik
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN37996
| | - Ariel Amir
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA02134
- Department of Complex Systems, Weizmann Institute of Science, Rehovot7610001, Israel
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10
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Bhat D, Hauf S, Plessy C, Yokobayashi Y, Pigolotti S. Speed variations of bacterial replisomes. eLife 2022; 11:75884. [PMID: 35877175 PMCID: PMC9385209 DOI: 10.7554/elife.75884] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 07/13/2022] [Indexed: 11/13/2022] Open
Abstract
Replisomes are multi-protein complexes that replicate genomes with remarkable speed and accuracy. Despite their importance, their dynamics is poorly characterized, especially in vivo. In this paper, we present an approach to infer the replisome dynamics from the DNA abundance distribution measured in a growing bacterial population. Our method is sensitive enough to detect subtle variations of the replisome speed along the genome. As an application, we experimentally measured the DNA abundance distribution in Escherichia coli populations growing at different temperatures using deep sequencing. We find that the average replisome speed increases nearly five-fold between 17°C and 37°C. Further, we observe wave-like variations of the replisome speed along the genome. These variations correlate with previously observed variations of the mutation rate, suggesting a common dynamical origin. Our approach has the potential to elucidate replication dynamics in E. coli mutants and in other bacterial species.
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Affiliation(s)
- Deepak Bhat
- Biological Complexity Unit, Okinawa Institute of Science and Technology, Onna, Japan
| | - Samuel Hauf
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology, Onna, Japan
| | - Charles Plessy
- Genomics and Regulatory Systems Unit, Okinawa Institute of Science and Technology, Onna, Japan
| | - Yohei Yokobayashi
- Nucleic Acid Chemistry and Engineering Unit, Okinawa Institute of Science and Technology, Onna, Japan
| | - Simone Pigolotti
- Biological Complexity Unit, Okinawa Institute of Science and Technology, Onna, Japan
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11
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Pompa-Monroy DA, Iglesias AL, Dastager SG, Thorat MN, Olivas-Sarabia A, Valdez-Castro R, Hurtado-Ayala LA, Cornejo-Bravo JM, Pérez-González GL, Villarreal-Gómez LJ. Comparative Study of Polycaprolactone Electrospun Fibers and Casting Films Enriched with Carbon and Nitrogen Sources and Their Potential Use in Water Bioremediation. MEMBRANES 2022; 12:327. [PMID: 35323802 PMCID: PMC8951516 DOI: 10.3390/membranes12030327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/04/2022] [Accepted: 03/11/2022] [Indexed: 12/02/2022]
Abstract
Augmenting bacterial growth is of great interest to the biotechnological industry. Hence, the effect of poly (caprolactone) fibrous scaffolds to promote the growth of different bacterial strains of biological and industrial interest was evaluated. Furthermore, different types of carbon (glucose, fructose, lactose and galactose) and nitrogen sources (yeast extract, glycine, peptone and urea) were added to the scaffold to determinate their influence in bacterial growth. Bacterial growth was observed by scanning electron microscopy; thermal characteristics were also evaluated; bacterial cell growth was measured by ultraviolet-visible spectrophotometry at 600-nm. Fibers produced have an average diameter between 313 to 766 nm, with 44% superficial porosity of the scaffolds, a glass transition around ~64 °C and a critical temperature of ~338 °C. The fibrous scaffold increased the cell growth of Escherichia coli by 23% at 72 h, while Pseudomonas aeruginosa and Staphylococcus aureus increased by 36% and 95% respectively at 48 h, when compared to the normal growth of their respective bacterial cultures. However, no significant difference in bacterial growth between the scaffolds and the casted films could be observed. Cell growth depended on a combination of several factors: type of bacteria, carbon or nitrogen sources, casted films or 3D scaffolds. Microscopy showed traces of a biofilm formation around 3 h in culture of P. aeruginosa. Water bioremediation studies showed that P. aeruginosa on poly (caprolactone)/Glucose fibers was effective in removing 87% of chromium in 8 h.
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Affiliation(s)
- Daniella Alejandra Pompa-Monroy
- Facultad de Ciencias de la Ingeniería y Tecnología, Universidad Autónoma de Baja California, Tijuana 21500, Baja California, Mexico; (D.A.P.-M.); (A.L.I.); (G.L.P.-G.)
- Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Tijuana 22260, Baja California, Mexico; (L.A.H.-A.); (J.M.C.-B.)
| | - Ana Leticia Iglesias
- Facultad de Ciencias de la Ingeniería y Tecnología, Universidad Autónoma de Baja California, Tijuana 21500, Baja California, Mexico; (D.A.P.-M.); (A.L.I.); (G.L.P.-G.)
| | - Syed Gulam Dastager
- National Collection of Industrial Microorganism (NCIM), CSIR-National Chemical Laboratory, Pune 41008, Maharashtra, India; (S.G.D.); (M.N.T.)
| | - Meghana Namdeo Thorat
- National Collection of Industrial Microorganism (NCIM), CSIR-National Chemical Laboratory, Pune 41008, Maharashtra, India; (S.G.D.); (M.N.T.)
| | - Amelia Olivas-Sarabia
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada 22860, Baja California, Mexico; (A.O.-S.); (R.V.-C.)
| | - Ricardo Valdez-Castro
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada 22860, Baja California, Mexico; (A.O.-S.); (R.V.-C.)
| | - Lilia Angélica Hurtado-Ayala
- Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Tijuana 22260, Baja California, Mexico; (L.A.H.-A.); (J.M.C.-B.)
| | - José Manuel Cornejo-Bravo
- Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Tijuana 22260, Baja California, Mexico; (L.A.H.-A.); (J.M.C.-B.)
| | - Graciela Lizeth Pérez-González
- Facultad de Ciencias de la Ingeniería y Tecnología, Universidad Autónoma de Baja California, Tijuana 21500, Baja California, Mexico; (D.A.P.-M.); (A.L.I.); (G.L.P.-G.)
- Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Tijuana 22260, Baja California, Mexico; (L.A.H.-A.); (J.M.C.-B.)
| | - Luis Jesús Villarreal-Gómez
- Facultad de Ciencias de la Ingeniería y Tecnología, Universidad Autónoma de Baja California, Tijuana 21500, Baja California, Mexico; (D.A.P.-M.); (A.L.I.); (G.L.P.-G.)
- Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Tijuana 22260, Baja California, Mexico; (L.A.H.-A.); (J.M.C.-B.)
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12
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Czerwińska-Główka D, Skonieczna M, Barylski A, Golba S, Przystaś W, Zabłocka-Godlewska E, Student S, Cwalina B, Krukiewicz K. Bifunctional conducting polymer matrices with antibacterial and neuroprotective effects. Bioelectrochemistry 2021; 144:108030. [PMID: 34896782 DOI: 10.1016/j.bioelechem.2021.108030] [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: 08/23/2021] [Revised: 10/24/2021] [Accepted: 11/29/2021] [Indexed: 11/02/2022]
Abstract
Current trends in the field of neural tissue engineering include the design of advanced biomaterials combining excellent electrochemical performance with versatile biological characteristics. The purpose of this work was to develop an antibacterial and neuroprotective coating based on a conducting polymer - poly(3,4-ethylenedioxypyrrole) (PEDOP), loaded with an antibiotic agent - tetracycline (Tc). Employing an electrochemical technique to immobilize Tc within a growing polymer matrix allowed to fabricate robust PEDOP/Tc coatings with a high charge storage capacity (63.65 ± 6.05 mC/cm2), drug release efficiency (629.4 µg/cm2 ± 62.7 µg/cm2), and low charge transfer resistance (2.4 ± 0.1 kΩ), able to deliver a stable electrical signal. PEDOP/Tc were found to exhibit strong antimicrobial effects against Gram-negative bacteria Escherichia coli, expressed through negligible adhesion, reduction in viability, and a characteristic elongation of bacterial cells. Cytocompatibility and neuroprotective effects were evaluated using a rat neuroblastoma B35 cell line, and were analyzed using MTT, cell cycle, and Annexin-V apoptosis assays. The presence of Tc was found to enhance neural cell viability and neurite outgrowth. The results confirmed that PEDOP/Tc can serve as an efficient neural electrode coating able to enhance charge transfer, as well as to exhibit bifunctional biological characteristics, different for eukaryotic and prokaryotic cells.
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Affiliation(s)
- Dominika Czerwińska-Główka
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M.Strzody 9, 44-100 Gliwice, Poland
| | - Magdalena Skonieczna
- Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, B. Krzywoustego 8, 44-100 Gliwice, Poland
| | - Adrian Barylski
- Institute of Materials Engineering, University of Silesia, 75 Pulku Piechoty, 41-500 Chorzow, Poland
| | - Sylwia Golba
- Institute of Materials Engineering, University of Silesia, 75 Pulku Piechoty, 41-500 Chorzow, Poland
| | - Wioletta Przystaś
- Biotechnology Centre, Silesian University of Technology, B. Krzywoustego 8, 44-100 Gliwice, Poland; Department of Air Protection, Faculty of Energy and Environmental Engineering, Silesian University of Technology, S. Konarskiego 22B, 44-100 Gliwice, Poland
| | - Ewa Zabłocka-Godlewska
- Biotechnology Centre, Silesian University of Technology, B. Krzywoustego 8, 44-100 Gliwice, Poland; Department of Air Protection, Faculty of Energy and Environmental Engineering, Silesian University of Technology, S. Konarskiego 22B, 44-100 Gliwice, Poland
| | - Sebastian Student
- Department of Systems Biology and Engineering, Faculty of Automatic Control, Electronics and Computer Science, Silesian University of Technology, Akademicka 16, 44-100 Gliwice, Poland; Biotechnology Centre, Silesian University of Technology, B. Krzywoustego 8, 44-100 Gliwice, Poland
| | - Beata Cwalina
- Biotechnology Centre, Silesian University of Technology, B. Krzywoustego 8, 44-100 Gliwice, Poland; Department of Environmental Biotechnology, Faculty of Energy and Environmental Engineering, Silesian University of Technology, S.Konarskiego 18, 44-100 Gliwice, Poland
| | - Katarzyna Krukiewicz
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, M.Strzody 9, 44-100 Gliwice, Poland.
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13
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Czerwińska-Główka D, Krukiewicz K. Guidelines for a Morphometric Analysis of Prokaryotic and Eukaryotic Cells by Scanning Electron Microscopy. Cells 2021; 10:3304. [PMID: 34943812 PMCID: PMC8699492 DOI: 10.3390/cells10123304] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/11/2021] [Accepted: 11/24/2021] [Indexed: 11/17/2022] Open
Abstract
The invention of a scanning electron microscopy (SEM) pushed the imaging methods and allowed for the observation of cell details with a high resolution. Currently, SEM appears as an extremely useful tool to analyse the morphology of biological samples. The aim of this paper is to provide a set of guidelines for using SEM to analyse morphology of prokaryotic and eukaryotic cells, taking as model cases Escherichia coli bacteria and B-35 rat neuroblastoma cells. Herein, we discuss the necessity of a careful sample preparation and provide an optimised protocol that allows to observe the details of cell ultrastructure (≥ 50 nm) with a minimum processing effort. Highlighting the versatility of morphometric descriptors, we present the most informative parameters and couple them with molecular processes. In this way, we indicate the wide range of information that can be collected through SEM imaging of biological materials that makes SEM a convenient screening method to detect cell pathology.
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Affiliation(s)
| | - Katarzyna Krukiewicz
- Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, 44-100 Gliwice, Poland;
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14
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Bai Y, He C, Chu P, Long J, Li X, Fu X. Spatial modulation of individual behaviors enables an ordered structure of diverse phenotypes during bacterial group migration. eLife 2021; 10:67316. [PMID: 34726151 PMCID: PMC8563000 DOI: 10.7554/elife.67316] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022] Open
Abstract
Coordination of diverse individuals often requires sophisticated communications and high-order computational abilities. Microbial populations can exhibit diverse individualistic behaviors, and yet can engage in collective migratory patterns with a spatially sorted arrangement of phenotypes. However, it is unclear how such spatially sorted patterns emerge from diverse individuals without complex computational abilities. Here, by investigating the single-cell trajectories during group migration, we discovered that, despite the constant migrating speed of a group, the drift velocities of individual bacteria decrease from the back to the front. With a Langevin-type modeling framework, we showed that this decreasing profile of drift velocities implies the spatial modulation of individual run-and-tumble random motions, and enables the bacterial population to migrate as a pushed wave front. Theoretical analysis and stochastic simulations further predicted that the pushed wave front can help a diverse population to stay in a tight group, while diverse individuals perform the same type of mean reverting processes around centers orderly aligned by their chemotactic abilities. This mechanism about the emergence of orderly collective migration from diverse individuals is experimentally demonstrated by titration of bacterial chemoreceptor abundance. These results reveal a simple computational principle for emergent ordered behaviors from heterogeneous individuals. Organisms living in large groups often have to move together in order to navigate, forage for food, and increase their roaming range. Such groups are often made up of distinct individuals that must integrate their different behaviors in order to migrate in the same direction at a similar pace. For instance, for the bacteria Escherichia coli to travel as a condensed group, they must coordinate their response to a set of chemical signals called chemoattractants that tell them where to go. The chemoattractants surrounding the bacteria are unequally distributed so that there is more of them at the front than the back of the group. During migration, each bacterium moves towards this concentration gradient in a distinct way, spontaneously rotating its direction in a ‘run-and-tumble’ motion that guides it towards areas where there are high levels of these chemical signals. In addition to this variability, how well individual bacteria are able to swim up the gradient also differs within the population. Bacteria that are better at sensing the chemoattractant gradient are placed at the front of the group, while those that are worst are shifted towards the back. This spatial arrangement is thought to help the bacteria migrate together. But how E. coli organize themselves in to this pattern is unclear, especially as they cannot communicate directly with one another and display such diverse, randomized behaviors. To help answer this question, Bai, He et al. discovered a general principle that describes how single bacterial cells move within a group. The results showed that E. coli alter their run-and-tumble motion depending on where they reside within the population: individuals at the rear drift faster so they can catch up with the group, while those leading the group drift slower to draw themselves back. This ‘reversion behavior’ allows the migrating bacteria to travel at a constant speed around a mean position relative to the group. A cell’s drifting speed is determined by how well it moves towards the chemoattractant and its response to the concentration gradient. As a result, the mean position around which the bacterium accelerates or deaccelerates will vary depending on how sensitive it is to the chemoattractant gradient. The E. coli therefore spatially arrange themselves so that the more sensitive bacteria are located at the front of the group where the gradient is shallower; and cells that are less sensitive are located towards the back where the gradient is steeper. These findings suggest a general principle for how bacteria form ordered patterns whilst migrating as a collective group. This behavior could also apply to other populations of distinct individuals, such as ants following a trail or flocks of birds migrating in between seasons.
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Affiliation(s)
- Yang Bai
- CAS Key Laboratory for Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Caiyun He
- CAS Key Laboratory for Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Pan Chu
- CAS Key Laboratory for Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Junjiajia Long
- Yale University, Department of Physics, New Haven, United States
| | - Xuefei Li
- CAS Key Laboratory for Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiongfei Fu
- CAS Key Laboratory for Quantitative Engineering Biology, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
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15
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Colin A, Micali G, Faure L, Cosentino Lagomarsino M, van Teeffelen S. Two different cell-cycle processes determine the timing of cell division in Escherichia coli. eLife 2021; 10:67495. [PMID: 34612203 PMCID: PMC8555983 DOI: 10.7554/elife.67495] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
Cells must control the cell cycle to ensure that key processes are brought to completion. In Escherichia coli, it is controversial whether cell division is tied to chromosome replication or to a replication-independent inter-division process. A recent model suggests instead that both processes may limit cell division with comparable odds in single cells. Here, we tested this possibility experimentally by monitoring single-cell division and replication over multiple generations at slow growth. We then perturbed cell width, causing an increase of the time between replication termination and division. As a consequence, replication became decreasingly limiting for cell division, while correlations between birth and division and between subsequent replication-initiation events were maintained. Our experiments support the hypothesis that both chromosome replication and a replication-independent inter-division process can limit cell division: the two processes have balanced contributions in non-perturbed cells, while our width perturbations increase the odds of the replication-independent process being limiting.
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Affiliation(s)
- Alexandra Colin
- Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
| | - Gabriele Micali
- Department of Environmental Microbiology, Dübendorf, Switzerland.,Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Louis Faure
- Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France
| | - Marco Cosentino Lagomarsino
- IFOM, FIRC Institute of Molecular Oncology, Milan, Italy.,Physics Department, University of Milan, and INFN, Milan, Italy
| | - Sven van Teeffelen
- Microbial Morphogenesis and Growth Laboratory, Institut Pasteur, Paris, France.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Canada
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16
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Winkle JJ, Karamched BR, Bennett MR, Ott W, Josić K. Emergent spatiotemporal population dynamics with cell-length control of synthetic microbial consortia. PLoS Comput Biol 2021; 17:e1009381. [PMID: 34550968 PMCID: PMC8489724 DOI: 10.1371/journal.pcbi.1009381] [Citation(s) in RCA: 14] [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: 04/02/2021] [Revised: 10/04/2021] [Accepted: 08/25/2021] [Indexed: 12/04/2022] Open
Abstract
The increased complexity of synthetic microbial biocircuits highlights the need for distributed cell functionality due to concomitant increases in metabolic and regulatory burdens imposed on single-strain topologies. Distributed systems, however, introduce additional challenges since consortium composition and spatiotemporal dynamics of constituent strains must be robustly controlled to achieve desired circuit behaviors. Here, we address these challenges with a modeling-based investigation of emergent spatiotemporal population dynamics using cell-length control in monolayer, two-strain bacterial consortia. We demonstrate that with dynamic control of a strain's division length, nematic cell alignment in close-packed monolayers can be destabilized. We find that this destabilization confers an emergent, competitive advantage to smaller-length strains-but by mechanisms that differ depending on the spatial patterns of the population. We used complementary modeling approaches to elucidate underlying mechanisms: an agent-based model to simulate detailed mechanical and signaling interactions between the competing strains, and a reductive, stochastic lattice model to represent cell-cell interactions with a single rotational parameter. Our modeling suggests that spatial strain-fraction oscillations can be generated when cell-length control is coupled to quorum-sensing signaling in negative feedback topologies. Our research employs novel methods of population control and points the way to programming strain fraction dynamics in consortial synthetic biology.
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Affiliation(s)
- James J Winkle
- Department of Mathematics, University of Houston, Houston, Texas, United States of America
| | - Bhargav R Karamched
- Department of Mathematics, Florida State University, Tallahassee, Florida, United States of America
- Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida, United States of America
| | - Matthew R Bennett
- Department of Bioengineering, Rice University, Houston, Texas, United States of America
- Department of Biosciences, Rice University, Houston, Texas, United States of America
| | - William Ott
- Department of Mathematics, University of Houston, Houston, Texas, United States of America
| | - Krešimir Josić
- Department of Mathematics, University of Houston, Houston, Texas, United States of America
- Department of Biosciences, Rice University, Houston, Texas, United States of America
- Department of Biology and Biochemistry, University of Houston, Houston, Texas, United States of America
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17
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Wong F, Wilson S, Helbig R, Hegde S, Aftenieva O, Zheng H, Liu C, Pilizota T, Garner EC, Amir A, Renner LD. Understanding Beta-Lactam-Induced Lysis at the Single-Cell Level. Front Microbiol 2021; 12:712007. [PMID: 34421870 PMCID: PMC8372035 DOI: 10.3389/fmicb.2021.712007] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 06/30/2021] [Indexed: 12/04/2022] Open
Abstract
Mechanical rupture, or lysis, of the cytoplasmic membrane is a common cell death pathway in bacteria occurring in response to β-lactam antibiotics. A better understanding of the cellular design principles governing the susceptibility and response of individual cells to lysis could indicate methods of potentiating β-lactam antibiotics and clarify relevant aspects of cellular physiology. Here, we take a single-cell approach to bacterial cell lysis to examine three cellular features—turgor pressure, mechanosensitive channels, and cell shape changes—that are expected to modulate lysis. We develop a mechanical model of bacterial cell lysis and experimentally analyze the dynamics of lysis in hundreds of single Escherichia coli cells. We find that turgor pressure is the only factor, of these three cellular features, which robustly modulates lysis. We show that mechanosensitive channels do not modulate lysis due to insufficiently fast solute outflow, and that cell shape changes result in more severe cellular lesions but do not influence the dynamics of lysis. These results inform a single-cell view of bacterial cell lysis and underscore approaches of combatting antibiotic tolerance to β-lactams aimed at targeting cellular turgor.
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Affiliation(s)
- Felix Wong
- Department of Biological Engineering, Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA, United States.,Infectious Disease and Microbiome Program, Broad Institute of MIT and Harvard, Cambridge, MA, United States.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Sean Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States.,Center for Systems Biology, Harvard University, Cambridge, MA, United States
| | - Ralf Helbig
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
| | - Smitha Hegde
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Olha Aftenieva
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
| | - Hai Zheng
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Chenli Liu
- CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Teuta Pilizota
- Centre for Synthetic and Systems Biology, Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, United States.,Center for Systems Biology, Harvard University, Cambridge, MA, United States
| | - Ariel Amir
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, United States
| | - Lars D Renner
- Leibniz Institute of Polymer Research and the Max Bergmann Center of Biomaterials, Dresden, Germany
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18
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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: 11] [Impact Index Per Article: 3.7] [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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19
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Abstract
Transcriptional regulators that integrate cellular and environmental signals to control cell division are well known in bacteria and eukaryotes, but their existence is poorly understood in archaea. We identified a conserved gene (cdrS) that encodes a small protein and is highly transcribed in the model archaeon Haloferax volcanii. The cdrS gene could not be deleted, but CRISPR interference (CRISPRi)-mediated repression of the cdrS gene caused slow growth and cell division defects and changed the expression of multiple genes and their products associated with cell division, protein degradation, and metabolism. Consistent with this complex regulatory network, overexpression of cdrS inhibited cell division, whereas overexpression of the operon encoding both CdrS and a tubulin-like cell division protein (FtsZ2) stimulated division. Chromatin immunoprecipitation-DNA sequencing (ChIP-Seq) identified 18 DNA-binding sites of the CdrS protein, including one upstream of the promoter for a cell division gene, ftsZ1, and another upstream of the essential gene dacZ, encoding diadenylate cyclase involved in c-di-AMP signaling, which is implicated in the regulation of cell division. These findings suggest that CdrS is a transcription factor that plays a central role in a regulatory network coordinating metabolism and cell division. IMPORTANCE Cell division is a central mechanism of life and is essential for growth and development. Members of the Bacteria and Eukarya have different mechanisms for cell division, which have been studied in detail. In contrast, cell division in members of the Archaea is still understudied, and its regulation is poorly understood. Interestingly, different cell division machineries appear in members of the Archaea, with the Euryarchaeota using a cell division apparatus based on the tubulin-like cytoskeletal protein FtsZ, as in bacteria. Here, we identify the small protein CdrS as essential for survival and a central regulator of cell division in the euryarchaeon Haloferax volcanii. CdrS also appears to coordinate other cellular pathways, including synthesis of signaling molecules and protein degradation. Our results show that CdrS plays a sophisticated role in cell division, including regulation of numerous associated genes. These findings are expected to initiate investigations into conditional regulation of division in archaea.
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20
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Conchouso D, Al-Ma'abadi A, Behzad H, Alarawi M, Hosokawa M, Nishikawa Y, Takeyama H, Mineta K, Gojobori T. Integration of Droplet Microfluidic Tools for Single-Cell Functional Metagenomics: An Engineering Head Start. GENOMICS, PROTEOMICS & BIOINFORMATICS 2021; 19:504-518. [PMID: 34952209 PMCID: PMC8864243 DOI: 10.1016/j.gpb.2021.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 02/09/2021] [Accepted: 03/09/2021] [Indexed: 11/25/2022]
Abstract
Droplet microfluidic techniques have shown promising outcome to study single cells at high throughput. However, their adoption in laboratories studying “-omics” sciences is still irrelevant due to the complex and multidisciplinary nature of the field. To facilitate their use, here we provide engineering details and organized protocols for integrating three droplet-based microfluidic technologies into the metagenomic pipeline to enable functional screening of bioproducts at high throughput. First, a device encapsulating single cells in droplets at a rate of ∼250 Hz is described considering droplet size and cell growth. Then, we expand on previously reported fluorescence-activated droplet sorting systems to integrate the use of 4 independent fluorescence-exciting lasers (i.e., 405, 488, 561, and 637 nm) in a single platform to make it compatible with different fluorescence-emitting biosensors. For this sorter, both hardware and software are provided and optimized for effortlessly sorting droplets at 60 Hz. Then, a passive droplet merger is also integrated into our pipeline to enable adding new reagents to already-made droplets at a rate of 200 Hz. Finally, we provide an optimized recipe for manufacturing these chips using silicon dry-etching tools. Because of the overall integration and the technical details presented here, our approach allows biologists to quickly use microfluidic technologies and achieve both single-cell resolution and high-throughput capability (>50,000 cells/day) for mining and bioprospecting metagenomic data
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Affiliation(s)
- David Conchouso
- Department of Industrial and Mechanical Engineering, Universidad de las Américas Puebla, Puebla 72810, Mexico; Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Amani Al-Ma'abadi
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Hayedeh Behzad
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Mohammed Alarawi
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Masahito Hosokawa
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo 162-0041, Japan; Department of Life Science and Medical Bioscience, Waseda University, Tokyo 162-8480, Japan; Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan
| | - Yohei Nishikawa
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo 162-0041, Japan; Computational Bio Big-Data Open Innovation Laboratory, AIST-Waseda University, Tokyo 169-0072, Japan
| | - Haruko Takeyama
- Research Organization for Nano & Life Innovation, Waseda University, Tokyo 162-0041, Japan; Department of Life Science and Medical Bioscience, Waseda University, Tokyo 162-8480, Japan; Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan; Computational Bio Big-Data Open Innovation Laboratory, AIST-Waseda University, Tokyo 169-0072, Japan
| | - Katsuhiko Mineta
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Computer, Electrical, and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Takashi Gojobori
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
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21
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Threshold accumulation of a constitutive protein explains E. coli cell-division behavior in nutrient upshifts. Proc Natl Acad Sci U S A 2021; 118:2016391118. [PMID: 33931503 DOI: 10.1073/pnas.2016391118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Despite a boost of recent progress in dynamic single-cell measurements and analyses in Escherichia coli, we still lack a mechanistic understanding of the determinants of the decision to divide. Specifically, the debate is open regarding the processes linking growth and chromosome replication to division and on the molecular origin of the observed "adder correlations," whereby cells divide, adding roughly a constant volume independent of their initial volume. In order to gain insight into these questions, we interrogate dynamic size-growth behavior of single cells across nutrient upshifts with a high-precision microfluidic device. We find that the division rate changes quickly after nutrients change, much before growth rate goes to a steady state, and in a way that adder correlations are robustly conserved. Comparison of these data to simple mathematical models falsifies proposed mechanisms, where replication-segregation or septum completions are the limiting step for cell division. Instead, we show that the accumulation of a putative constitutively expressed "P-sector divisor" protein explains the behavior during the shift.
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22
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Precise regulation of the relative rates of surface area and volume synthesis in bacterial cells growing in dynamic environments. Nat Commun 2021; 12:1975. [PMID: 33785742 PMCID: PMC8009875 DOI: 10.1038/s41467-021-22092-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/12/2021] [Indexed: 11/23/2022] Open
Abstract
The steady-state size of bacterial cells correlates with nutrient-determined growth rate. Here, we explore how rod-shaped bacterial cells regulate their morphology during rapid environmental changes. We quantify cellular dimensions throughout passage cycles of stationary-phase cells diluted into fresh medium and grown back to saturation. We find that cells exhibit characteristic dynamics in surface area to volume ratio (SA/V), which are conserved across genetic and chemical perturbations as well as across species and growth temperatures. A mathematical model with a single fitting parameter (the time delay between surface and volume synthesis) is quantitatively consistent with our SA/V experimental observations. The model supports that this time delay is due to differential expression of volume and surface-related genes, and that the first division after dilution occurs at a tightly controlled SA/V. Our minimal model thus provides insight into the connections between bacterial growth rate and cell shape in dynamic environments. Bacterial cells actively change their size and shape in response to external environments. Here, Shi et al. explore how cells regulate their morphology during rapid environmental changes, showing that the characteristic dynamics of surface area-to-volume ratio are conserved across genetic and chemical perturbations, as well as across species and growth temperatures.
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23
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Zhou Z, Tang H, Wang W, Zhang L, Su F, Wu Y, Bai L, Li S, Sun Y, Tao F, Xu P. A cold shock protein promotes high-temperature microbial growth through binding to diverse RNA species. Cell Discov 2021; 7:15. [PMID: 33727528 PMCID: PMC7966797 DOI: 10.1038/s41421-021-00246-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 01/27/2021] [Indexed: 01/18/2023] Open
Abstract
Endowing mesophilic microorganisms with high-temperature resistance is highly desirable for industrial microbial fermentation. Here, we report a cold-shock protein (CspL) that is an RNA chaperone protein from a lactate producing thermophile strain (Bacillus coagulans 2–6), which is able to recombinantly confer strong high-temperature resistance to other microorganisms. Transgenic cspL expression massively enhanced high-temperature growth of Escherichia coli (a 2.4-fold biomass increase at 45 °C) and eukaryote Saccharomyces cerevisiae (a 2.6-fold biomass increase at 36 °C). Importantly, we also found that CspL promotes growth rates at normal temperatures. Mechanistically, bio-layer interferometry characterized CspL’s nucleotide-binding functions in vitro, while in vivo we used RNA-Seq and RIP-Seq to reveal CspL’s global effects on mRNA accumulation and CspL’s direct RNA binding targets, respectively. Thus, beyond establishing how a cold-shock protein chaperone provides high-temperature resistance, our study introduces a strategy that may facilitate industrial thermal fermentation.
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Affiliation(s)
- Zikang Zhou
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Hongzhi Tang
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
| | - Weiwei Wang
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Lige Zhang
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Fei Su
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Yuanting Wu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Linquan Bai
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Sicong Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, Hubei, 430071, People's Republic of China
| | - Yuhui Sun
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan, Hubei, 430071, People's Republic of China
| | - Fei Tao
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, and School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, People's Republic of China.
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24
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Zhang Q, Zhang Z, Shi H. Cell Size Is Coordinated with Cell Cycle by Regulating Initiator Protein DnaA in E. coli. Biophys J 2020; 119:2537-2557. [PMID: 33189684 DOI: 10.1016/j.bpj.2020.10.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/22/2020] [Accepted: 10/16/2020] [Indexed: 10/23/2022] Open
Abstract
Sixty years ago, bacterial cell size was found to be an exponential function of growth rate. Fifty years ago, a more general relationship was proposed, in which cell mass was equal to the initiation mass multiplied by 2 to the power of the ratio of the total time of C and D periods to the doubling time. This relationship has recently been experimentally confirmed by perturbing doubling time, C period, D period, or initiation mass. However, the underlying molecular mechanism remains unclear. Here, we developed a theoretical model for initiator protein DnaA mediating DNA replication initiation in Escherichia coli. We introduced an initiation probability function for competitive binding of DnaA-ATP and DnaA-ADP at oriC. We established a kinetic description of regulatory processes (e.g., expression regulation, titration, inactivation, and reactivation) of DnaA. Cell size as a spatial constraint also participates in the regulation of DnaA. By simulating DnaA kinetics, we obtained a regular DnaA oscillation coordinated with cell cycle and a converged cell size that matches replication initiation frequency to the growth rate. The relationship between the simulated cell size and growth rate, C period, D period, or initiation mass reproduces experimental results. The model also predicts how DnaA number and initiation mass vary with perturbation parameters, comparable with experimental data. The results suggest that 1) when growth rate, C period, or D period changes, the regulation of DnaA determines the invariance of initiation mass; 2) ppGpp inhibition of replication initiation may be important for the growth rate independence of initiation mass because three possible mechanisms therein produce different DnaA dynamics, which is experimentally verifiable; and 3) perturbation of some DnaA regulatory process causes a changing initiation mass or even an abnormal cell cycle. This study may provide clues for concerted control of cell size and cell cycle in synthetic biology.
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Affiliation(s)
- Qing Zhang
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China.
| | - Zhichao Zhang
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China
| | - Hualin Shi
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
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25
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Bacterial Biofilm Formation Using PCL/Curcumin Electrospun Fibers and Its Potential Use for Biotechnological Applications. MATERIALS 2020; 13:ma13235556. [PMID: 33291216 PMCID: PMC7729789 DOI: 10.3390/ma13235556] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/20/2020] [Accepted: 10/27/2020] [Indexed: 01/19/2023]
Abstract
Electrospun nanofibers are used for many applications due to their large surface area, mechanical properties, and bioactivity. Bacterial biofilms are the cause of numerous problems in biomedical devices and in the food industry. On the other hand, these bacterial biofilms can produce interesting metabolites. Hence, the objective of this study is to evaluate the efficiency of poly (Ɛ- caprolactone)/Curcumin (PCL/CUR) nanofibers to promote bacterial biofilm formation. These scaffolds were characterized by scanning electron microscopy (SEM), which showed homogeneous fibers with diameters between 441-557 nm; thermogravimetric analysis and differential scanning calorimetry (TGA and DSC) demonstrated high temperature resilience with degradation temperatures over >350 °C; FTIR and 1H-NMR serve as evidence of CUR incorporation in the PCL fibers. PCL/CUR scaffolds successfully promoted the formation of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa biofilms. These results will be valuable in the study of controlled harvesting of pathogenic biofilms as well as in metabolites production for biotechnological purposes.
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26
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Liang B, Quan B, Li J, Loton C, Bredeche MF, Lindner AB, Xu L. Artificial modulation of cell width significantly affects the division time of Escherichia coli. Sci Rep 2020; 10:17847. [PMID: 33082450 PMCID: PMC7576201 DOI: 10.1038/s41598-020-74778-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/07/2020] [Indexed: 12/14/2022] Open
Abstract
Bacterial cells have characteristic spatial and temporal scales. For instance, Escherichia coli, the typical rod-shaped bacteria, always maintains a relatively constant cell width and cell division time. However, whether the external physical perturbation of cell width has an impact on cell division time remains largely unexplored. In this work, we developed two microchannel chips, namely straight channels and ‘necked’ channels, to precisely regulate the width of E. coli cells and to investigate the correlation between cell width and division time of the cells. Our results show that, in the straight channels, the wide cells divide much slower than narrow cells. In the ‘necked’ channels, the cell division is remarkably promoted compared to that in straight channels with the same width. Besides, fluorescence time-lapse microscopy imaging of FtsZ dynamics shows that the cell pre-constriction time is more sensitive to cell width perturbation than cell constriction time. Finally, we revealed a significant anticorrelation between the death rate and the division rate of cell populations with different widths. Our work provides new insights into the correlation between the geometrical property and division time of E. coli cells and sheds new light on the future study of spatial–temporal correlation in cell physiology.
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Affiliation(s)
- Baihui Liang
- Center for Nano and Micro Mechanics, School of Aerospace Engineering, Tsinghua University, Beijing, 100084, People's Republic of China
| | - Baogang Quan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Junjie Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, People's Republic of China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.,Songshan Lake Materials Laboratory, Dongguan, 523808, Guangdong, People's Republic of China
| | - Chantal Loton
- Systems Engineering and Evolution Dynamics Lab, INSERM U1001, Paris Descartes University, 75014, Paris, France.,Faculty of Medicine, Paris Descartes University, 75014, Paris, France
| | - Marie-Florence Bredeche
- Systems Engineering and Evolution Dynamics Lab, INSERM U1001, Paris Descartes University, 75014, Paris, France.,Faculty of Medicine, Paris Descartes University, 75014, Paris, France
| | - Ariel B Lindner
- Systems Engineering and Evolution Dynamics Lab, INSERM U1001, Paris Descartes University, 75014, Paris, France.,Faculty of Medicine, Paris Descartes University, 75014, Paris, France.,Centre for Research and Interdisciplinarity (CRI), Paris Descartes University, 75014, Paris, France
| | - Luping Xu
- Center for Nano and Micro Mechanics, School of Aerospace Engineering, Tsinghua University, Beijing, 100084, People's Republic of China.
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27
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Teimouri H, Mukherjee R, Kolomeisky AB. Stochastic Mechanisms of Cell-Size Regulation in Bacteria. J Phys Chem Lett 2020; 11:8777-8782. [PMID: 33001652 DOI: 10.1021/acs.jpclett.0c02627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
How bacteria are able to maintain their sizes remains an open question. It is believed that cells have narrow distributions of sizes as a consequence of a homeostasis that allows bacteria to function at the optimal conditions. Several phenomenological approaches to explain these observations have been presented, but the microscopic origins of the cell-size regulation are still not understood. Here, we propose a new stochastic approach to investigate the molecular mechanisms of maintaining the cell sizes in bacteria. It is argued that the cell-size regulation is a result of coupling of two stochastic processes, cell growth and division, which eliminates the need for introducing the thresholds. Dynamic properties of the system are explicitly evaluated, and it is shown that the model is consistent with the experimentally supported adder principle of the cell-size regulation. In addition, theoretical predictions agree with experimental observations on E. coli bacteria. Theoretical analysis clarifies some important features of bacterial cell growth.
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Affiliation(s)
- Hamid Teimouri
- Department of Chemistry, Rice University, Houston, Texas 77251, United States
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77251, United States
| | - Rupsha Mukherjee
- MTech, Biological Engineering, Indian Institute of Technology, Gandhinagar, Gujarat 382355, India
| | - Anatoly B Kolomeisky
- Department of Chemistry, Rice University, Houston, Texas 77251, United States
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77251, United States
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, United States
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
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28
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A bacterial size law revealed by a coarse-grained model of cell physiology. PLoS Comput Biol 2020; 16:e1008245. [PMID: 32986690 PMCID: PMC7553314 DOI: 10.1371/journal.pcbi.1008245] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/13/2020] [Accepted: 08/13/2020] [Indexed: 12/23/2022] Open
Abstract
Universal observations in Biology are sometimes described as “laws”. In E. coli, experimental studies performed over the past six decades have revealed major growth laws relating ribosomal mass fraction and cell size to the growth rate. Because they formalize complex emerging principles in biology, growth laws have been instrumental in shaping our understanding of bacterial physiology. Here, we discovered a novel size law that connects cell size to the inverse of the metabolic proteome mass fraction and the active fraction of ribosomes. We used a simple whole-cell coarse-grained model of cell physiology that combines the proteome allocation theory and the structural model of cell division. This integrated model captures all available experimental data connecting the cell proteome composition, ribosome activity, division size and growth rate in response to nutrient quality, antibiotic treatment and increased protein burden. Finally, a stochastic extension of the model explains non-trivial correlations observed in single cell experiments including the adder principle. This work provides a simple and robust theoretical framework for studying the fundamental principles of cell size determination in unicellular organisms. Bacteria respond to environmental changes by adjusting their molecular composition, cell size and growth rate. This plasticity is thought to result from years of evolution and to be at least in part optimal for bacterial physiology. Over the past decades, quantitative studies of bacterial growth have revealed simple phenomenological relationships, called “growth laws”, which link cell size and cell composition to the growth rate. Simplified mathematical models of cell physiology are useful tools to gain quantitative understanding of the molecular mechanisms that underlie growth laws. For instance, these models helped explaining how optimal allocation of cellular resource to physiological processes and pathways governs the cell molecular composition in response to specific environmental conditions. In this study, we have extended and integrated existing mathematical models and used experimental data from several recent studies to understand the co-regulation of cell composition, cell size and the cellular growth rate. The model predictions uncovered a novel “size law” that links cell size to the levels of metabolic proteins and the fraction of active ribosomes present in the cell. This work provides a useful theoretical tool and a quantitative basis for understanding mechanistically bacterial physiology as a function of external conditions.
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29
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Liu Y, Su A, Li J, Ledesma-Amaro R, Xu P, Du G, Liu L. Towards next-generation model microorganism chassis for biomanufacturing. Appl Microbiol Biotechnol 2020; 104:9095-9108. [DOI: 10.1007/s00253-020-10902-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/03/2020] [Accepted: 09/10/2020] [Indexed: 11/29/2022]
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30
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Ho PY, Martins BMC, Amir A. A Mechanistic Model of the Regulation of Division Timing by the Circadian Clock in Cyanobacteria. Biophys J 2020; 118:2905-2913. [PMID: 32497517 DOI: 10.1016/j.bpj.2020.04.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 04/02/2020] [Accepted: 04/30/2020] [Indexed: 11/15/2022] Open
Abstract
The cyanobacterium Synechococcus elongatus possesses a circadian clock in the form of a group of proteins whose concentrations and phosphorylation states oscillate with daily periodicity under constant conditions. The circadian clock regulates the cell cycle such that the timing of the cell divisions is biased toward certain times during the circadian period, but the mechanism underlying this phenomenon remains unclear. Here, we propose a mechanism in which a protein limiting for division accumulates at a rate proportional to the cell volume growth and is modulated by the clock. This "modulated rate" model, in which the clock signal is integrated over time to affect division timing, differs fundamentally from the previously proposed "gating" concept, in which the clock is assumed to suppress divisions during a specific time window. We found that although both models can capture the single-cell statistics of division timing in S. elongatus, only the modulated rate model robustly places divisions away from darkness during changes in the environment. Moreover, within the framework of the modulated rate model, existing experiments on S. elongatus are consistent with the simple mechanism that division timing is regulated by the accumulation of a division limiting protein in a phase with genes whose activity peaks at dusk.
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Affiliation(s)
- Po-Yi Ho
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts
| | - Bruno M C Martins
- Sainsbury Laboratory, University of Cambridge, Cambridge, United Kingdom
| | - Ariel Amir
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts.
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31
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General quantitative relations linking cell growth and the cell cycle in Escherichia coli. Nat Microbiol 2020; 5:995-1001. [PMID: 32424336 DOI: 10.1038/s41564-020-0717-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/01/2020] [Indexed: 01/15/2023]
Abstract
Growth laws emerging from studies of cell populations provide essential constraints on the global mechanisms that coordinate cell growth1-3. The foundation of bacterial cell cycle studies relies on two interconnected dogmas that were proposed more than 50 years ago-the Schaechter-Maaloe-Kjeldgaard growth law that relates cell mass to growth rate1 and Donachie's hypothesis of a growth-rate-independent initiation mass4. These dogmas spurred many efforts to understand their molecular bases and physiological consequences5-14. Although they are generally accepted in the fast-growth regime, that is, for doubling times below 1 h, extension of these dogmas to the slow-growth regime has not been consistently achieved. Here, through a quantitative physiological study of Escherichia coli cell cycles over an extensive range of growth rates, we report that neither dogma holds in either the slow- or fast-growth regime. In their stead, linear relations between the cell mass and the rate of chromosome replication-segregation were found across the range of growth rates. These relations led us to propose an integral-threshold model in which the cell cycle is controlled by a licensing process, the rate of which is related in a simple way to chromosomal dynamics. These results provide a quantitative basis for predictive understanding of cell growth-cell cycle relationships.
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32
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Ding Q, Ma D, Liu GQ, Li Y, Guo L, Gao C, Hu G, Ye C, Liu J, Liu L, Chen X. Light-powered Escherichia coli cell division for chemical production. Nat Commun 2020; 11:2262. [PMID: 32385264 PMCID: PMC7210317 DOI: 10.1038/s41467-020-16154-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 04/19/2020] [Indexed: 12/17/2022] Open
Abstract
Cell division can perturb the metabolic performance of industrial microbes. The C period of cell division starts from the initiation to the termination of DNA replication, whereas the D period is the bacterial division process. Here, we first shorten the C and D periods of E. coli by controlling the expression of the ribonucleotide reductase NrdAB and division proteins FtsZA through blue light and near-infrared light activation, respectively. It increases the specific surface area to 3.7 μm−1 and acetoin titer to 67.2 g·L−1. Next, we prolong the C and D periods of E. coli by regulating the expression of the ribonucleotide reductase NrdA and division protein inhibitor SulA through blue light activation-repression and near-infrared (NIR) light activation, respectively. It improves the cell volume to 52.6 μm3 and poly(lactate-co-3-hydroxybutyrate) titer to 14.31 g·L−1. Thus, the optogenetic-based cell division regulation strategy can improve the efficiency of microbial cell factories. Manipulation of genes controlling microbial shapes can affect bio-production. Here, the authors employ an optogenetic method to realize dynamic morphological engineering of E. coli replication and division and show the increased production of acetoin and poly(lactate-co-3-hydroxybutyrate).
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Affiliation(s)
- Qiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Danlei Ma
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Gao-Qiang Liu
- Hunan Provincial Key Laboratory for Forestry Biotechnology, Central South University of Forestry and Technology, 410004, Changsha, China
| | - Yang Li
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Liang Guo
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Guipeng Hu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Chao Ye
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Jia Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China.,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 214122, Wuxi, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, 214122, Wuxi, China. .,Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 214122, Wuxi, China.
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33
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White MA, Darmon E, Lopez-Vernaza MA, Leach DRF. DNA double strand break repair in Escherichia coli perturbs cell division and chromosome dynamics. PLoS Genet 2020; 16:e1008473. [PMID: 31895943 PMCID: PMC6959608 DOI: 10.1371/journal.pgen.1008473] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 01/14/2020] [Accepted: 12/16/2019] [Indexed: 11/18/2022] Open
Abstract
To prevent the transmission of damaged genomic material between generations, cells require a system for accommodating DNA repair within their cell cycles. We have previously shown that Escherichia coli cells subject to a single, repairable site-specific DNA double-strand break (DSB) per DNA replication cycle reach a new average cell length, with a negligible effect on population growth rate. We show here that this new cell size distribution is caused by a DSB repair-dependent delay in completion of cell division. This delay occurs despite unperturbed cell size regulated initiation of both chromosomal DNA replication and cell division. Furthermore, despite DSB repair altering the profile of DNA replication across the genome, the time required to complete chromosomal duplication is invariant. The delay in completion of cell division is accompanied by a DSB repair-dependent delay in individualization of sister nucleoids. We suggest that DSB repair events create inter-sister connections that persist until those chromosomes are separated by a closing septum.
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Affiliation(s)
- Martin A. White
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, The King’s Buildings, Edinburgh, United Kingdom
- Department of Molecular and Cellular Biology, Harvard University, Cambridge MA, United States of America
| | - Elise Darmon
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, The King’s Buildings, Edinburgh, United Kingdom
| | - Manuel A. Lopez-Vernaza
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, The King’s Buildings, Edinburgh, United Kingdom
| | - David R. F. Leach
- Institute of Cell Biology, School of Biological Sciences, University of Edinburgh, The King’s Buildings, Edinburgh, United Kingdom
- * E-mail:
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34
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Vuaridel‐Thurre G, Vuaridel AR, Dhar N, McKinney JD. Computational Analysis of the Mutual Constraints between Single‐Cell Growth and Division Control Models. ACTA ACUST UNITED AC 2019; 4:e1900103. [DOI: 10.1002/adbi.201900103] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 11/05/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Gaëlle Vuaridel‐Thurre
- School of Life SciencesSwiss Federal Institute of Technology in Lausanne (EPFL) CH‐1015 Lausanne Switzerland
| | - Ambroise R. Vuaridel
- School of Life SciencesSwiss Federal Institute of Technology in Lausanne (EPFL) CH‐1015 Lausanne Switzerland
| | - Neeraj Dhar
- School of Life SciencesSwiss Federal Institute of Technology in Lausanne (EPFL) CH‐1015 Lausanne Switzerland
| | - John D. McKinney
- School of Life SciencesSwiss Federal Institute of Technology in Lausanne (EPFL) CH‐1015 Lausanne Switzerland
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35
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An evolutionarily stable strategy to colonize spatially extended habitats. Nature 2019; 575:664-668. [PMID: 31695198 PMCID: PMC6883132 DOI: 10.1038/s41586-019-1734-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 10/03/2019] [Indexed: 11/28/2022]
Abstract
The ability of a species to colonize newly available habitas is crucial to its overall fitness. Generally, motility and fast expansion is expected to be beneficial to the colonization process and hence to organismal fitness. Here we apply a unique evolution protocol to investigate phenotypical requirements for colonizing habitats of different sizes during range expansion of chemotaxing bacteria. Contrary to the intuitive expectation that faster is better, we show the existence of an optimal expansion speed associated with a given habitat size. Our analysis showed this effect to arise from interactions among pioneering cells at the front of the expanding population, and revealed a simple, evolutionary stable strategy for colonizing a habitat of a specific size: to expand at a speed given by the product of the growth rate and habitat size. These results illustrates stability-to-invasion as a powerful principle for the selection of phenotypes in complex ecological processes.
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36
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Facchetti G, Knapp B, Chang F, Howard M. Reassessment of the Basis of Cell Size Control Based on Analysis of Cell-to-Cell Variability. Biophys J 2019; 117:1728-1738. [PMID: 31630810 PMCID: PMC6838950 DOI: 10.1016/j.bpj.2019.09.031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 08/19/2019] [Accepted: 09/23/2019] [Indexed: 11/12/2022] Open
Abstract
Fundamental mechanisms governing cell size control and homeostasis are still poorly understood. The relationship between sizes at division and birth in single cells is used as a metric to categorize the basis of size homeostasis. Cells dividing at a fixed size regardless of birth size (sizer) are expected to show a division-birth slope of zero, whereas cells dividing after growing for a fixed size increment (adder) have an expected slope of +1. These two theoretical values are, however, rarely experimentally observed. For example, rod-shaped fission yeast Schizosaccharomyces pombe cells, which divide at a fixed surface area, exhibit a division-birth slope for cell lengths of 0.25 ± 0.02, significantly different from the expected sizer value of zero. Here, we investigate possible reasons for this discrepancy by developing a mathematical model of sizer control including the relevant sources of variation. Our results support pure sizer control and show that deviation from zero slope is exaggerated by measurement of an inappropriate geometrical quantity (e.g., length instead of area), combined with cell-to-cell radius variability. The model predicts that mutants with greater errors in size sensing or septum positioning paradoxically appear to behave as better sizers. Furthermore, accounting for cell width variability, we show that pure sizer control can in some circumstances reproduce the apparent adder behavior observed in Escherichia coli. These findings demonstrate that analysis of geometric variation can lead to new insights into cell size control.
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Affiliation(s)
- Giuseppe Facchetti
- Department of Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom; Department of Systems Biology, University of Surrey, Guildford, United Kingdom.
| | - Benjamin Knapp
- Department of Cell and Tissue Biology, University of California-San Francisco, San Francisco, California; Biophysics Program, Stanford University, Stanford, California
| | - Fred Chang
- Department of Cell and Tissue Biology, University of California-San Francisco, San Francisco, California
| | - Martin Howard
- Department of Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom.
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37
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Lee S, Wu LJ, Errington J. Microfluidic time-lapse analysis and reevaluation of the Bacillus subtilis cell cycle. Microbiologyopen 2019; 8:e876. [PMID: 31197963 PMCID: PMC6813450 DOI: 10.1002/mbo3.876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/03/2019] [Accepted: 05/13/2019] [Indexed: 12/24/2022] Open
Abstract
Recent studies taking advantage of automated single-cell time-lapse analysis have reignited interest in the bacterial cell cycle. Several studies have highlighted alternative models, such as Sizer and Adder, which differ essentially in relation to whether cells can measure their present size or their amount of growth since birth. Most of the recent work has been done with Escherichia coli. We set out to study the well-characterized Gram-positive bacterium, Bacillus subtilis, at the single-cell level, using an accurate fluorescent marker for division as well as a marker for completion of chromosome replication. Our results are consistent with the Adder model in both fast and slow growth conditions tested, and with Sizer but only at the slower growth rate. We also find that cell size variation arises not only from the expected variation in size at division but also that division site offset from mid-cell contributes to a significant degree. Finally, although traditional cell cycle models imply a strong connection between the termination of a round of replication and subsequent division, we find that at the single-cell level these events are largely disconnected.
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Affiliation(s)
- Seoungjun Lee
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Medical SchoolNewcastle UniversityNewcastle‐upon‐TyneUK
- Present address:
Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and NeuroscienceKing’s College LondonLondonUK
| | - Ling Juan Wu
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Medical SchoolNewcastle UniversityNewcastle‐upon‐TyneUK
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Medical SchoolNewcastle UniversityNewcastle‐upon‐TyneUK
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38
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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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39
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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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40
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Si F, Le Treut G, Sauls JT, Vadia S, Levin PA, Jun S. Mechanistic Origin of Cell-Size Control and Homeostasis in Bacteria. Curr Biol 2019; 29:1760-1770.e7. [PMID: 31104932 DOI: 10.1016/j.cub.2019.04.062] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/18/2019] [Accepted: 04/24/2019] [Indexed: 02/06/2023]
Abstract
Evolutionarily divergent bacteria share a common phenomenological strategy for cell-size homeostasis under steady-state conditions. In the presence of inherent physiological stochasticity, cells following this "adder" principle gradually return to their steady-state size by adding a constant volume between birth and division, regardless of their size at birth. However, the mechanism of the adder has been unknown despite intense efforts. In this work, we show that the adder is a direct consequence of two general processes in biology: (1) threshold-accumulation of initiators and precursors required for cell division to a respective fixed number-and (2) balanced biosynthesis-maintenance of their production proportional to volume growth. This mechanism is naturally robust to static growth inhibition but also allows us to "reprogram" cell-size homeostasis in a quantitatively predictive manner in both Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. By generating dynamic oscillations in the concentration of the division protein FtsZ, we were able to oscillate cell size at division and systematically break the adder. In contrast, periodic induction of replication initiator protein DnaA caused oscillations in cell size at initiation but did not alter division size or the adder. Finally, we were able to restore the adder phenotype in slow-growing E. coli, the only known steady-state growth condition wherein E. coli significantly deviates from the adder, by repressing active degradation of division proteins. Together, these results show that cell division and replication initiation are independently controlled at the gene-expression level and that division processes exclusively drive cell-size homeostasis in bacteria. VIDEO ABSTRACT.
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Affiliation(s)
- Fangwei Si
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Guillaume Le Treut
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - John T Sauls
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stephen Vadia
- Department of Biology, Washington University in St. Louis, Saint Louis, MO 63130, USA
| | - Petra Anne Levin
- Department of Biology, Washington University in St. Louis, Saint Louis, MO 63130, USA
| | - Suckjoon Jun
- Department of Physics, University of California, San Diego, La Jolla, CA 92093, USA; Section of Molecular Biology, Division of Biology, University of California, San Diego, La Jolla, CA 92093, USA.
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41
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Bacillus subtilis cell diameter is determined by the opposing actions of two distinct cell wall synthetic systems. Nat Microbiol 2019; 4:1294-1305. [PMID: 31086310 PMCID: PMC6656618 DOI: 10.1038/s41564-019-0439-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 03/28/2019] [Indexed: 11/08/2022]
Abstract
Rod-shaped bacteria grow by adding material into their cell wall via the action of two spatially distinct enzymatic systems: the Rod complex moves around the cell circumference, whereas class A penicillin-binding proteins (aPBPs) do not. To understand how the combined action of these two systems defines bacterial dimensions, we examined how each affects the growth and width of Bacillus subtilis as well as the mechanical anisotropy and orientation of material within their sacculi. Rod width is not determined by MreB, rather it depends on the balance between the systems: the Rod complex reduces diameter, whereas aPBPs increase it. Increased Rod-complex activity correlates with an increased density of directional MreB filaments and a greater fraction of directional PBP2a enzymes. This increased circumferential synthesis increases the relative quantity of oriented material within the sacculi, making them more resistant to stretching across their width, thereby reinforcing rod shape. Together, these experiments explain how the combined action of the two main cell wall synthetic systems builds and maintains rods of different widths. Escherichia coli Rod mutants also show the same correlation between width and directional MreB filament density, suggesting this model may be generalizable to bacteria that elongate via the Rod complex.
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42
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Very rapid flow cytometric assessment of antimicrobial susceptibility during the apparent lag phase of microbial (re)growth. Microbiology (Reading) 2019; 165:439-454. [DOI: 10.1099/mic.0.000777] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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43
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Marine psychrophile-derived cold-active polygalacturonase: Enhancement of productivity in Thalassospira frigidphilosprofundus S3BA12 by whole cell immobilization. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.01.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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44
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Norris V. Successive Paradigm Shifts in the Bacterial Cell Cycle and Related Subjects. Life (Basel) 2019; 9:E27. [PMID: 30866455 PMCID: PMC6462897 DOI: 10.3390/life9010027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 02/28/2019] [Accepted: 03/04/2019] [Indexed: 11/26/2022] Open
Abstract
A paradigm shift in one field can trigger paradigm shifts in other fields. This is illustrated by the paradigm shifts that have occurred in bacterial physiology following the discoveries that bacteria are not unstructured, that the bacterial cell cycle is not controlled by the dynamics of peptidoglycan, and that the growth rates of bacteria in the same steady-state population are not at all the same. These paradigm shifts are having an effect on longstanding hypotheses about the regulation of the bacterial cell cycle, which appear increasingly to be inadequate. I argue that, just as one earthquake can trigger others, an imminent paradigm shift in the regulation of the bacterial cell cycle will have repercussions or "paradigm quakes" on hypotheses about the origins of life and about the regulation of the eukaryotic cell cycle.
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Affiliation(s)
- Vic Norris
- Laboratory of Microbiology Signals and Microenvironment, University of Rouen, 76821 Mont Saint Aignan, France.
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45
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Nouri H, Monnier AF, Fossum-Raunehaug S, Maciag-Dorszynska M, Cabin-Flaman A, Képès F, Wegrzyn G, Szalewska-Palasz A, Norris V, Skarstad K, Janniere L. Multiple links connect central carbon metabolism to DNA replication initiation and elongation in Bacillus subtilis. DNA Res 2019; 25:641-653. [PMID: 30256918 PMCID: PMC6289782 DOI: 10.1093/dnares/dsy031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 08/17/2018] [Indexed: 12/27/2022] Open
Abstract
DNA replication is coupled to growth by an unknown mechanism. Here, we investigated this coupling by analyzing growth and replication in 15 mutants of central carbon metabolism (CCM) cultivated in three rich media. In about one-fourth of the condition tested, defects in replication resulting from changes in initiation or elongation were detected. This uncovered 11 CCM genes important for replication and showed that some of these genes have an effect in one, two or three media. Additional results presented here and elsewhere (Jannière, L., Canceill, D., Suski, C., et al. (2007), PLoS One, 2, e447.) showed that, in the LB medium, the CCM genes important for DNA elongation (gapA and ackA) are genetically linked to the lagging strand polymerase DnaE while those important for initiation (pgk and pykA) are genetically linked to the replication enzymes DnaC (helicase), DnaG (primase) and DnaE. Our work thus shows that the coupling between growth and replication involves multiple, medium-dependent links between CCM and replication. They also suggest that changes in CCM may affect initiation by altering the functional recruitment of DnaC, DnaG and DnaE at the chromosomal origin, and may affect elongation by altering the activity of DnaE at the replication fork. The underlying mechanism is discussed.
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Affiliation(s)
- Hamid Nouri
- iSSB, Génopole, CNRS, UEVE, Université Paris-Saclay, Evry France.,MICALIS, INRA, Jouy en Josas, France
| | | | | | | | | | - François Képès
- iSSB, Génopole, CNRS, UEVE, Université Paris-Saclay, Evry France
| | - Grzegorz Wegrzyn
- Department of Molecular Biology, University of Gdansk, Gdansk, Poland
| | | | - Vic Norris
- Laboratoire MERCI, AMMIS, Faculté des Sciences, Mont-Saint-Aignan, France
| | - Kirsten Skarstad
- Department of Cell Biology, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Laurent Janniere
- iSSB, Génopole, CNRS, UEVE, Université Paris-Saclay, Evry France.,MICALIS, INRA, Jouy en Josas, France
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46
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Shi H, Bratton BP, Gitai Z, Huang KC. How to Build a Bacterial Cell: MreB as the Foreman of E. coli Construction. Cell 2019. [PMID: 29522748 DOI: 10.1016/j.cell.2018.02.050] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cell shape matters across the kingdoms of life, and cells have the remarkable capacity to define and maintain specific shapes and sizes. But how are the shapes of micron-sized cells determined from the coordinated activities of nanometer-sized proteins? Here, we review general principles that have surfaced through the study of rod-shaped bacterial growth. Imaging approaches have revealed that polymers of the actin homolog MreB play a central role. MreB both senses and changes cell shape, thereby generating a self-organizing feedback system for shape maintenance. At the molecular level, structural and computational studies indicate that MreB filaments exhibit tunable mechanical properties that explain their preference for certain geometries and orientations along the cylindrical cell body. We illustrate the regulatory landscape of rod-shape formation and the connectivity between cell shape, cell growth, and other aspects of cell physiology. These discoveries provide a framework for future investigations into the architecture and construction of microbes.
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Affiliation(s)
- Handuo Shi
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Benjamin P Bratton
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, 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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47
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Kurita K, Shin R, Tabei T, Shiomi D. Relation between rotation of MreB actin and cell width of Escherichia coli. Genes Cells 2019; 24:259-265. [PMID: 30597729 DOI: 10.1111/gtc.12667] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 12/25/2018] [Accepted: 12/26/2018] [Indexed: 12/27/2022]
Abstract
Bacterial cells, including Escherichia coli and Bacillus subtilis, continuously elongate and divide. Although the cell width is maintained during cell cycle, the molecular mechanisms involved in its regulation remain unknown. MreB has been implicated to play a role in maintaining cell width. Several point mutations in mreB that affect cell width have been identified. The MreB protein forms clusters or polymers in the cell and moves along annular tracks perpendicular to the long axis. This rotation is coupled with peptidoglycan synthesis. Here, we focused on two MreB mutants, MreBA125V and MreBA174T . Cells producing MreBA125V and MreBA174T were thinner and thicker than WT cells, and MreBA125V and MreBA174T rotated faster and slower than WT MreB, respectively. We observed that the rotation rate correlated with the cell wall synthesis rate. Thus, we conclude that the velocity of MreB rotation also affects cell width, that is, the faster the MreB rotates, the thinner the cell width is.
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Affiliation(s)
- Keisuke Kurita
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Ryota Shin
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Tsutomu Tabei
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
| | - Daisuke Shiomi
- Department of Life Science, College of Science, Rikkyo University, Tokyo, Japan
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48
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Facchetti G, Knapp B, Flor-Parra I, Chang F, Howard M. Reprogramming Cdr2-Dependent Geometry-Based Cell Size Control in Fission Yeast. Curr Biol 2019; 29:350-358.e4. [PMID: 30639107 PMCID: PMC6345630 DOI: 10.1016/j.cub.2018.12.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 10/23/2018] [Accepted: 12/10/2018] [Indexed: 11/21/2022]
Abstract
How cell size is determined and maintained remains unclear, even in simple model organisms. In proliferating cells, cell size is regulated by coordinating growth and division through sizer, adder, or timer mechanisms or through some combination [1, 2]. Currently, the best-characterized example of sizer behavior is in fission yeast, Schizosaccharomyces pombe, which enters mitosis at a minimal cell size threshold. The peripheral membrane kinase Cdr2 localizes in clusters (nodes) on the medial plasma membrane and promotes mitotic entry [3]. Here, we show that the Cdr2 nodal density, which scales with cell size, is used by the cell to sense and control its size. By analyzing cells of different widths, we first show that cdr2+ cells divide at a fixed cell surface area. However, division in the cdr2Δ mutant is more closely specified by cell volume, suggesting that Cdr2 is essential for area sensing and supporting the existence of a Cdr2-independent secondary sizer mechanism more closely based on volume. To investigate how Cdr2 nodes may sense area, we derive a minimal mathematical model that incorporates the cytoplasmic kinase Ssp1 as a Cdr2 activator. The model predicts that a cdr2 mutant in an Ssp1 phosphorylation site (cdr2-T166A) [4] should form nodes whose density registers cell length. We confirm this prediction experimentally and find that thin cells now follow this new scaling by dividing at constant length instead of area. This work supports the role of Cdr2 as a sizer factor and highlights the importance of studying geometrical aspects of size control.
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Affiliation(s)
| | - Benjamin Knapp
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Ignacio Flor-Parra
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide/CSIC/Junta de Andalucia, Seville, Spain
| | - Fred Chang
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA.
| | - Martin Howard
- Computational and Systems Biology, John Innes Centre, Norwich, UK.
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49
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Micali G, Grilli J, Osella M, Cosentino Lagomarsino M. Concurrent processes set E. coli cell division. SCIENCE ADVANCES 2018; 4:eaau3324. [PMID: 30417095 PMCID: PMC6224021 DOI: 10.1126/sciadv.aau3324] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/03/2018] [Indexed: 05/30/2023]
Abstract
A cell can divide only upon completion of chromosome segregation; otherwise, its daughters would lose genetic material. However, we do not know whether the partitioning of chromosomes is the key event for the decision to divide. We show how key trends in single-cell data reject the classic idea of replication-segregation as the rate-limiting process for cell division. Instead, the data agree with a model where two concurrent processes (setting replication initiation and interdivision time) set cell division on competing time scales. During each cell cycle, division is set by the slowest process (an "AND" gate). The concept of transitions between cell cycle stages as decisional processes integrating multiple inputs instead of cascading from orchestrated steps can affect the way we think of the cell cycle in general.
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Affiliation(s)
- Gabriele Micali
- Department of Environmental Microbiology, Eawag, Dübendorf, Switzerland
- Department of Environmental Systems Science, ETH Zürich, Zürich, Switzerland
| | - Jacopo Grilli
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, USA
| | - Matteo Osella
- Physics Department, University of Turin, Via Giuria 16, Torino, Italy
- I.N.F.N., Torino, Italy
| | - Marco Cosentino Lagomarsino
- Sorbonne Universités, UPMC University Paris 06, Paris, France
- CNRS, UMR 7238, Paris, France
- IFOM, FIRC Institute of Molecular Oncology, Milan, Italy
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50
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Abstract
Bacterial cell size depends on growth rate, cell cycle progression, and the cell volume per origin upon initiating chromosome replication (initiation volume). Here, we perform the first systematic and quantitative study of the effect of hyperosmotic stress on the E. coli cell size and cell cycle. We find that hyperosmotic stress significantly reduces the initiation volume. The reduced initiation volume is attributed to the increased DnaA concentration caused by water loss at high osmolarity, indicating a fundamental role of water content in cell size and cell cycle regulation. Bacterial cell size is closely associated with biomass growth and cell cycle progression, including chromosome replication and cell division. It is generally proposed that Escherichia coli cells tightly control the timing of chromosome replication through maintaining a constant cell volume per origin upon initiating chromosome replication (constant initiation volume) under various growth conditions. Here, we quantitatively characterize the cell size and cell cycle of Escherichia coli cells growing exponentially under hyperosmotic stress, which is a common environmental stressor that profoundly affects the bacterial water content. The bacterial cell size is reduced by hyperosmotic stress, even though the C and D periods are remarkably prolonged, indicating a significantly reduced initiation volume. The reduced initiation volume originates from the higher concentration of DnaA initiator protein caused by water loss at high osmolarity. Our study shows suggests a fundamental role of water content in regulating bacterial cell size and has also revealed a new role of the DnaA protein in regulating the chromosome replication elongation beyond regulating the replication initiation process. IMPORTANCE Bacterial cell size depends on growth rate, cell cycle progression, and the cell volume per origin upon initiating chromosome replication (initiation volume). Here, we perform the first systematic and quantitative study of the effect of hyperosmotic stress on the E. coli cell size and cell cycle. We find that hyperosmotic stress significantly reduces the initiation volume. The reduced initiation volume is attributed to the increased DnaA concentration caused by water loss at high osmolarity, indicating a fundamental role of water content in cell size and cell cycle regulation.
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