1
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Vidal PJ, Pérez AP, Yahya G, Aldea M. Transcriptomic balance and optimal growth are determined by cell size. Mol Cell 2024; 84:3288-3301.e3. [PMID: 39084218 DOI: 10.1016/j.molcel.2024.07.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/11/2024] [Accepted: 07/08/2024] [Indexed: 08/02/2024]
Abstract
Cell size and growth are intimately related across the evolutionary scale, but whether cell size is important to attain maximal growth or fitness is still an open question. We show that growth rate is a non-monotonic function of cell volume, with maximal values around the critical size of wild-type yeast cells. The transcriptome of yeast and mouse cells undergoes a relative inversion in response to cell size, which we associate theoretically and experimentally with the necessary genome-wide diversity in RNA polymerase II affinity for promoters. Although highly expressed genes impose strong negative effects on fitness when the DNA/mass ratio is reduced, transcriptomic alterations mimicking the relative inversion by cell size strongly restrain cell growth. In all, our data indicate that cells set the critical size to obtain a properly balanced transcriptome and, as a result, maximize growth and fitness during proliferation.
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Affiliation(s)
- Pedro J Vidal
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain
| | - Alexis P Pérez
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain; Department of Basic Sciences, Universitat Internacional de Catalunya, 08195 Sant Cugat del Vallès, Barcelona, Spain
| | - Galal Yahya
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain; Department of Microbiology and Immunology, School of Pharmacy, Zagazig University, 44511 Zagazig, Egypt.
| | - Martí Aldea
- Molecular Biology Institute of Barcelona (IBMB), CSIC, 08028 Barcelona, Catalonia, Spain; Department of Basic Sciences, Universitat Internacional de Catalunya, 08195 Sant Cugat del Vallès, Barcelona, Spain.
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2
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Li F, Yu H, Zhang B, Hu C, Lan F, Wang Y, You Z, Liu Q, Tang R, Zhang J, Li C, Shi L, Li WW, Nealson KH, Liu Z, Song H. Engineered Cell Elongation Promotes Extracellular Electron Transfer of Shewanella Oneidensis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2403067. [PMID: 39234800 DOI: 10.1002/advs.202403067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 08/12/2024] [Indexed: 09/06/2024]
Abstract
To investigate how cell elongation impacts extracellular electron transfer (EET) of electroactive microorganisms (EAMs), the division of model EAM Shewanella oneidensis (S. oneidensis) MR-1 is engineered by reducing the formation of cell divisome. Specially, by blocking the translation of division proteins via anti-sense RNAs or expressing division inhibitors, the cellular length and output power density are all increased. Electrophysiological and transcriptomic results synergistically reveal that the programmed cell elongation reinforces EET by enhancing NADH oxidation, inner-membrane quinone pool, and abundance of c-type cytochromes. Moreover, cell elongation enhances hydrophobicity due to decreased cell-surface polysaccharide, thus facilitates the initial surface adhesion stage during biofilm formation. The output current and power density all increase in positive correction with cellular length. However, inhibition of cell division reduces cell growth, which is then restored by quorum sensing-based dynamic regulation of cell growth and elongation phases. The QS-regulated elongated strain thus enables a cell length of 143.6 ± 40.3 µm (72.6-fold of that of S. oneidensis MR-1), which results in an output power density of 248.0 ± 10.6 mW m-2 (3.41-fold of that of S. oneidensis MR-1) and exhibits superior potential for pollutant treatment. Engineering cellular length paves an innovate avenue for enhancing the EET of EAMs.
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Affiliation(s)
- Feng Li
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Huan Yu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Baocai Zhang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Chaoning Hu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Fei Lan
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Yuxuan Wang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Zixuan You
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Qijing Liu
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Rui Tang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Junqi Zhang
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Chao Li
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
| | - Liang Shi
- Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geoscience in Wuhan, Wuhan, Hubei, 430074, China
| | - Wen-Wei Li
- Chinese Academy of Sciences Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science & Technology of China, Hefei, 230026, China
| | - Kenneth H Nealson
- Departments of Earth Science & Biological Sciences, University of Southern California, 4953 Harriman Ave., South Pasadena, CA, 91030, USA
| | - ZhanYing Liu
- Center for Energy Conservation and Emission Reduction in Fermentation Industry in Inner Mongolia, Engineering Research Center of Inner Mongolia for Green Manufacturing in Bio-fermentation Industry, and School of Chemical Engineering, Inner Mongolia University of Technology, Inner Mongolia, Hohhot, 010051, China
| | - Hao Song
- Frontier Science Center for Synthetic Biology (Ministry of Education), Key Laboratory of Systems Bioengineering, and School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China
- Haihe Laboratory of Sustainable Chemical Transformations, Tianjin, 300192, China
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3
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Liu Y, Chu K, Hua Z, Li Q, Lu Y, Ye F, Dong Y, Li X. Dynamics of antibiotic resistance genes in the sediments of a water-diversion lake and its human exposure risk behaviour. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 929:172563. [PMID: 38641096 DOI: 10.1016/j.scitotenv.2024.172563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/21/2024]
Abstract
The dynamics and exposure risk behaviours of antibiotic resistance genes (ARGs) in the sediments of water-diversion lakes remain poorly understood. In this study, spatiotemporal investigations of ARG profiles in sediments targeting non-water (NWDP) and water diversion periods (WDP) were conducted in Luoma Lake, a typical water-diversion lake, and an innovative dynamics-based risk assessment framework was constructed to evaluate ARG exposure risks to local residents. ARGs in sediments were significantly more abundant in the WDP than in the NWDP, but there was no significant variation in their spatial distribution in either period. Moreover, the pattern of ARG dissemination in sediments was unchanged between the WDP and NWDP, with horizontal gene transfer (HGT) and vertical gene transfer (VGT) contributing to ARG dissemination in both periods. However, water diversion altered the pattern in lake water, with HGT and VGT in the NWDP but only HGT in the WDP, which were critical pathways for the dissemination of ARGs. The significantly lower ARG sediment-water partition coefficient in the WDP indicated that water diversion could shift the fate of ARGs and facilitate their aqueous partitioning. Risk assessment showed that all age groups faced a higher human exposure risk of ARGs (HERA) in the WDP than in the NWDP, with the 45-59 age group having the highest risk. Furthermore, HERA increased overall with the bacterial carrying capacity in the local environment and peaked when the carrying capacity reached three (NWDP) or four (WDP) orders of magnitude higher than the observed bacterial population. HGT and VGT promoted, whereas ODF covering gene mutation and loss mainly reduced HERA in the lake. As the carrying capacity increased, the relative contribution of ODF to HERA remained relatively stable, whereas the dominant mechanism of HERA development shifted from HGT to VGT.
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Affiliation(s)
- Yuanyuan Liu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China
| | - Kejian Chu
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China.
| | - Zulin Hua
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China
| | - Qiming Li
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China
| | - Ying Lu
- Institute for Smart City of Chongqing University in Liyang, Liyang 213300, PR China
| | - Fuzhu Ye
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China
| | - Yueyang Dong
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China
| | - Xiaoqing Li
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, College of Environment, Hohai University, Nanjing 210098, PR China; Yangtze Institute for Conservation and Development, Hohai University, Nanjing 210098, PR China
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4
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McLellan JL, Hanson KK. Differential effects of translation inhibitors on Plasmodium berghei liver stage parasites. Life Sci Alliance 2024; 7:e202302540. [PMID: 38575357 PMCID: PMC10994859 DOI: 10.26508/lsa.202302540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 04/06/2024] Open
Abstract
Increasing numbers of antimalarial compounds are being identified that converge mechanistically at inhibition of cytoplasmic translation, regardless of the molecular target or mechanism. A deeper understanding of how their effectiveness as liver stage translation inhibitors relates to their chemoprotective potential could prove useful. Here, we probed that relationship using the Plasmodium berghei-HepG2 liver stage infection model. After determining translation inhibition EC50s for five compounds, we tested them at equivalent effective concentrations to compare the parasite response to, and recovery from, a brief period of translation inhibition in early schizogony, followed by parasites to 120 h post-infection to assess antiplasmodial effects of the treatment. We show compound-specific heterogeneity in single parasite and population responses to translation inhibitor treatment, with no single metric strongly correlated to the release of hepatic merozoites for all compounds. We also demonstrate that DDD107498 is capable of exerting antiplasmodial effects on translationally arrested liver stage parasites and uncover unexpected growth dynamics during the liver stage. Our results demonstrate that translation inhibition efficacy does not determine antiplasmodial efficacy for these compounds.
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Affiliation(s)
- James L McLellan
- https://ror.org/01kd65564 Department of Molecular Microbiology and Immunology and STCEID, University of Texas at San Antonio, San Antonio, TX, USA
| | - Kirsten K Hanson
- https://ror.org/01kd65564 Department of Molecular Microbiology and Immunology and STCEID, University of Texas at San Antonio, San Antonio, TX, USA
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5
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Medici IF, Bartrolí L, Guaimas FF, Fulgenzi FR, Molina CL, Sánchez IE, Comerci DJ, Mongiardini E, Soler-Bistué A. The distinct cell physiology of Bradyrhizobium at the population and cellular level. BMC Microbiol 2024; 24:129. [PMID: 38643099 PMCID: PMC11031950 DOI: 10.1186/s12866-024-03272-x] [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: 08/31/2023] [Accepted: 03/22/2024] [Indexed: 04/22/2024] Open
Abstract
The α-Proteobacteria belonging to Bradyrhizobium genus are microorganisms of extreme slow growth. Despite their extended use as inoculants in soybean production, their physiology remains poorly characterized. In this work, we produced quantitative data on four different isolates: B. diazoefficens USDA110, B. diazoefficiens USDA122, B. japonicum E109 and B. japonicum USDA6 which are representative of specific genomic profiles. Notably, we found conserved physiological traits conserved in all the studied isolates: (i) the lag and initial exponential growth phases display cell aggregation; (ii) the increase in specific nutrient concentration such as yeast extract and gluconate hinders growth; (iii) cell size does not correlate with culture age; and (iv) cell cycle presents polar growth. Meanwhile, fitness, cell size and in vitro growth widely vary across isolates correlating to ribosomal RNA operon number. In summary, this study provides novel empirical data that enriches the comprehension of the Bradyrhizobium (slow) growth dynamics and cell cycle.
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Affiliation(s)
- Ian F Medici
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina
| | - Leila Bartrolí
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina
| | - Francisco F Guaimas
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina
| | - Fabiana R Fulgenzi
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina
| | - Charo Luciana Molina
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina
| | - Ignacio Enrique Sánchez
- Laboratorio de Fisiología de Proteínas, Facultad de Ciencias Exactas y Naturales, CONICET Instituto de Química Biológica, Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Diego J Comerci
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina
| | - Elías Mongiardini
- Instituto de Biotecnología y Biología Molecular (IBBM), Facultad de Ciencias Exactas, UNLP y CCT-La Plata-CONICET, La Plata, Argentina
| | - Alfonso Soler-Bistué
- Instituto de Investigaciones Biotecnológicas, IIB-IIBIO, Universidad Nacional de San Martín- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Av. 25 de Mayo y Francia CP (1650), San Martín, Prov. de Buenos Aires, Argentina.
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6
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Coen E, Prusinkiewicz P. Developmental timing in plants. Nat Commun 2024; 15:2674. [PMID: 38531864 PMCID: PMC10965974 DOI: 10.1038/s41467-024-46941-1] [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: 10/31/2023] [Accepted: 03/13/2024] [Indexed: 03/28/2024] Open
Abstract
Plants exhibit reproducible timing of developmental events at multiple scales, from switches in cell identity to maturation of the whole plant. Control of developmental timing likely evolved for similar reasons that humans invented clocks: to coordinate events. However, whereas clocks are designed to run independently of conditions, plant developmental timing is strongly dependent on growth and environment. Using simplified models to convey key concepts, we review how growth-dependent and inherent timing mechanisms interact with the environment to control cyclical and progressive developmental transitions in plants.
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Affiliation(s)
- Enrico Coen
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich, NR4 7UH, UK.
| | - Przemyslaw Prusinkiewicz
- Department of Computer Science, University of Calgary, 2500 University Dr. N.W., Calgary, AB, T2N 1N4, Canada.
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7
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ElGamel M, Mugler A. Effects of Molecular Noise on Cell Size Control. PHYSICAL REVIEW LETTERS 2024; 132:098403. [PMID: 38489620 DOI: 10.1103/physrevlett.132.098403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 02/12/2024] [Indexed: 03/17/2024]
Abstract
Cells employ control strategies to maintain a stable size. Dividing at a target size (the "sizer" strategy) is thought to produce the tightest size distribution. However, this result follows from phenomenological models that ignore the molecular mechanisms required to implement the strategy. Here we investigate a simple mechanistic model for exponentially growing cells whose division is triggered at a molecular abundance threshold. We find that size noise inherits the molecular noise and is consequently minimized not by the sizer but by the "adder" strategy, where a cell divides after adding a target amount to its birth size. We derive a lower bound on size noise that agrees with publicly available data from six microfluidic studies on Escherichia coli bacteria.
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Affiliation(s)
- Motasem ElGamel
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Andrew Mugler
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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8
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von der Dunk SHA, Hogeweg P, Snel B. Intracellular signaling in proto-eukaryotes evolves to alleviate regulatory conflicts of endosymbiosis. PLoS Comput Biol 2024; 20:e1011860. [PMID: 38335232 PMCID: PMC10883579 DOI: 10.1371/journal.pcbi.1011860] [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: 08/20/2023] [Revised: 02/22/2024] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
The complex eukaryotic cell resulted from a merger between simpler prokaryotic cells, yet the role of the mitochondrial endosymbiosis with respect to other eukaryotic innovations has remained under dispute. To investigate how the regulatory challenges associated with the endosymbiotic state impacted genome and network evolution during eukaryogenesis, we study a constructive computational model where two simple cells are forced into an obligate endosymbiosis. Across multiple in silico evolutionary replicates, we observe the emergence of different mechanisms for the coordination of host and symbiont cell cycles, stabilizing the endosymbiotic relationship. In most cases, coordination is implicit, without signaling between host and symbiont. Signaling only evolves when there is leakage of regulatory products between host and symbiont. In the fittest evolutionary replicate, the host has taken full control of the symbiont cell cycle through signaling, mimicking the regulatory dominance of the nucleus over the mitochondrion that evolved during eukaryogenesis.
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Affiliation(s)
| | - Paulien Hogeweg
- Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Berend Snel
- Department of Biology, Utrecht University, Utrecht, The Netherlands
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9
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Li X, Li S, Wu Q. Non-Invasive Detection of Biomolecular Abundance from Fermentative Microorganisms via Raman Spectra Combined with Target Extraction and Multimodel Fitting. Molecules 2023; 29:157. [PMID: 38202740 PMCID: PMC10780171 DOI: 10.3390/molecules29010157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 12/24/2023] [Accepted: 12/25/2023] [Indexed: 01/12/2024] Open
Abstract
Biomolecular abundance detection of fermentation microorganisms is significant for the accurate regulation of fermentation, which is conducive to reducing fermentation costs and improving the yield of target products. However, the development of an accurate analytical method for the detection of biomolecular abundance still faces important challenges. Herein, we present a non-invasive biomolecular abundance detection method based on Raman spectra combined with target extraction and multimodel fitting. The high gain of the eXtreme Gradient Boosting (XGBoost) algorithm was used to extract the characteristic Raman peaks of metabolically active proteins and nucleic acids within E. coli and yeast. The test accuracy for different culture times and cell cycles of E. coli was 94.4% and 98.2%, respectively. Simultaneously, the Gaussian multi-peak fitting algorithm was exploited to calculate peak intensity from mixed peaks, which can improve the accuracy of biomolecular abundance calculations. The accuracy of Gaussian multi-peak fitting was above 0.9, and the results of the analysis of variance (ANOVA) measurements for the lag phase, log phase, and stationary phase of E. coli growth demonstrated highly significant levels, indicating that the intracellular biomolecular abundance detection was consistent with the classical cell growth law. These results suggest the great potential of the combination of microbial intracellular abundance, Raman spectra analysis, target extraction, and multimodel fitting as a method for microbial fermentation engineering.
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Affiliation(s)
- Xinli Li
- College of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, China
| | - Suyi Li
- College of Instrumentation and Electrical Engineering, Jilin University, Changchun 130061, China
| | - Qingyi Wu
- Changchun Institute of Optics, Fine Mechanics and Physics, Changchun 130033, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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10
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McLellan JL, Hanson KK. Translation inhibition efficacy does not determine the Plasmodium berghei liver stage antiplasmodial efficacy of protein synthesis inhibitors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.07.570699. [PMID: 38106175 PMCID: PMC10723475 DOI: 10.1101/2023.12.07.570699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Protein synthesis is a core cellular process, necessary throughout the complex lifecycle of Plasmodium parasites, thus specific translation inhibitors would be a valuable class of antimalarial drugs, capable of both treating symptomatic infections in the blood and providing chemoprotection by targeting the initial parasite population in the liver, preventing both human disease and parasite transmission back to the mosquito host. As increasing numbers of antiplasmodial compounds are identified that converge mechanistically at inhibition of cytoplasmic translation, regardless of molecular target or mechanism, it would be useful to gain deeper understanding of how their effectiveness as liver stage translation inhibitors relates to their chemoprotective potential. Here, we probed that relationship using the P. berghei-HepG2 liver stage infection model. Using o-propargyl puromycin-based labeling of the nascent proteome in P. berghei-infected HepG2 monolayers coupled with automated confocal feedback microscopy to generate unbiased, single parasite image sets of P. berghei liver stage translation, we determined translation inhibition EC50s for five compounds, encompassing parasite-specific aminoacyl tRNA synthetase inhibitors, compounds targeting the ribosome in both host and parasite, as well as DDD107498, which targets Plasmodium eEF2, and is a leading antimalarial candidate compound being clinically developed as cabamiquine. Compounds were then tested at equivalent effective concentrations to compare the parasite response to, and recovery from, a brief period of translation inhibition in early schizogony, with parasites followed up to 120 hours post-infection to assess liver stage antiplasmodial effects of the treatment. Our data conclusively show that translation inhibition efficacy per se does not determine a translation inhibitor's antiplasmodial efficacy. DDD107498 was the least effective translation inhibitor, yet exerted the strongest antimalarial effects at both 5x- and 10x EC50 concentrations. We show compound-specific heterogeneity in single parasite and population responses to translation inhibitor treatment, with no single metric strongly correlated to release of hepatic merozoites for all compound, demonstrate that DDD107498 is capable of exerting antiplasmodial effects on translationally arrested liver stage parasites, and uncover unexpected growth dynamics during the liver stage. Our results demonstrate that translation inhibition efficacy cannot function as a proxy for antiplasmodial effectiveness, and highlight the importance of exploring the ultimate, as well as proximate, mechanisms of action of these compounds on liver stage parasites.
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Affiliation(s)
- James L. McLellan
- University of Texas at San Antonio, Department of Molecular Microbiology and Immunology and STCEID, San Antonio TX, USA
| | - Kirsten K. Hanson
- University of Texas at San Antonio, Department of Molecular Microbiology and Immunology and STCEID, San Antonio TX, USA
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11
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Mortier J, Govers SK, Cambré A, Van Eyken R, Verheul J, den Blaauwen T, Aertsen A. Protein aggregates act as a deterministic disruptor during bacterial cell size homeostasis. Cell Mol Life Sci 2023; 80:360. [PMID: 37971522 PMCID: PMC11072981 DOI: 10.1007/s00018-023-05002-4] [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: 05/02/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 11/19/2023]
Abstract
Mechanisms underlying deviant cell size fluctuations among clonal bacterial siblings are generally considered to be cryptic and stochastic in nature. However, by scrutinizing heat-stressed populations of the model bacterium Escherichia coli, we uncovered the existence of a deterministic asymmetry in cell division that is caused by the presence of intracellular protein aggregates (PAs). While these structures typically locate at the cell pole and segregate asymmetrically among daughter cells, we now show that the presence of a polar PA consistently causes a more distal off-center positioning of the FtsZ division septum. The resulting increased length of PA-inheriting siblings persists over multiple generations and could be observed in both E. coli and Bacillus subtilis populations. Closer investigation suggests that a PA can physically perturb the nucleoid structure, which subsequently leads to asymmetric septation.
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Affiliation(s)
- Julien Mortier
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Sander K Govers
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
- Department of Biology, KU Leuven, Leuven, Belgium
| | - Alexander Cambré
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Ronald Van Eyken
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium
| | - Jolanda Verheul
- Swammerdam Institute for Life Sciences, Bacterial Cell Biology and Physiology, University of Amsterdam, Amsterdam, The Netherlands
| | - Tanneke den Blaauwen
- Swammerdam Institute for Life Sciences, Bacterial Cell Biology and Physiology, University of Amsterdam, Amsterdam, The Netherlands
| | - Abram Aertsen
- Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium.
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12
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Roller BRK, Hellerschmied C, Wu Y, Miettinen TP, Gomez AL, Manalis SR, Polz MF. Single-cell mass distributions reveal simple rules for achieving steady-state growth. mBio 2023; 14:e0158523. [PMID: 37671861 PMCID: PMC10653891 DOI: 10.1128/mbio.01585-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 07/14/2023] [Indexed: 09/07/2023] Open
Abstract
IMPORTANCE Microbiologists have watched clear liquid turn cloudy for over 100 years. While the cloudiness of a culture is proportional to its total biomass, growth rates from optical density measurements are challenging to interpret when cells change size. Many bacteria adjust their size at different steady-state growth rates, but also when shifting between starvation and growth. Optical density cannot disentangle how mass is distributed among cells. Here, we use single-cell mass measurements to demonstrate that a population of cells in batch culture achieves a stable mass distribution for only a short period of time. Achieving steady-state growth in rich medium requires low initial biomass concentrations and enough time for individual cell mass accumulation and cell number increase via cell division to balance out. Steady-state growth is important for reliable cell mass distributions and experimental reproducibility. We discuss how mass variation outside of steady-state can impact physiology, ecology, and evolution experiments.
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Affiliation(s)
- Benjamin R. K. Roller
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Cathrine Hellerschmied
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Yanqi Wu
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Teemu P. Miettinen
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Annika L. Gomez
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Scott R. Manalis
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Martin F. Polz
- Division of Microbial Ecology, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
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13
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Zhu W, Xi L, Qiao J, Du D, Wang Y, Morigen. Involvement of OxyR and Dps in the repression of replication initiation by DsrA small RNA in Escherichia coli. Gene 2023; 882:147659. [PMID: 37482259 DOI: 10.1016/j.gene.2023.147659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/14/2023] [Accepted: 07/19/2023] [Indexed: 07/25/2023]
Abstract
Regulation of the cell cycle process is an effective measure to ensure the stability and fidelity of genetic material during the reproduction of bacteria under different stresses. The small RNA DsrA helps bacteria adapt to environments by binding to multiple targets, but its association with the cell cycle remains unclear. Detection by flow cytometry, we first found that the knockout of dsrA promoted replication initiation, and corresponding overexpression of DsrA inhibited replication initiation in Escherichia coli. The absence of the chaperone protein Hfq, the DNA replication negative regulator protein Dps, or the transcription factor OxyR, was found to cause DsrA to no longer inhibit replication initiation. Excess DsrA promotes expression of the oxyR and dps gene, whereas β-galactosidase activity assay showed that deleting oxyR limited the enhancement of dps promoter transcriptional activity by DsrA. OxyR is a known positive regulator of Dps. Our data suggests that the effect of DsrA on replication initiation requires Hfq and that the upregulation of Dps expression by OxyR in response to DsrA levels may be a potential regulatory pathway for the negative regulation of DNA replication initiation.
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Affiliation(s)
- Weiwei Zhu
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Lingjun Xi
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Jiaxin Qiao
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Dongdong Du
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Yao Wang
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China
| | - Morigen
- State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, School of Life Sciences, Inner Mongolia University, Hohhot 010070, China.
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14
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Lough W, Weibel DB, Spagnolie SE. Self-buckling and self-writhing of semi-flexible microorganisms. SOFT MATTER 2023; 19:7349-7357. [PMID: 37740382 DOI: 10.1039/d3sm00572k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
The twisting and writhing of a cell body and associated mechanical stresses is an underappreciated constraint on microbial self-propulsion. Multi-flagellated bacteria can even buckle and writhe under their own activity as they swim through a viscous fluid. New equilibrium configurations and steady-state dynamics then emerge which depend on the organism's mechanical properties and on the oriented distribution of flagella along its surface. Modeling the cell body as a semi-flexible Kirchhoff rod and coupling the mechanics to a flagellar orientation field, we derive the Euler-Poincaré equations governing the dynamics of the system, and rationalize experimental observations of buckling and writhing of elongated swarmer cells of the bacterium Proteus mirabilis. A sequence of bifurcations is identified as the body is made more compliant, due to both buckling and torsional instabilities. These studies highlight a practical requirement for the stiffness of bacteria below which self-buckling occurs and cell motility becomes ineffective.
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Affiliation(s)
- Wilson Lough
- Department of Physics, University of Wisconsin-Madison, Madison, WI 53706, USA.
| | - Douglas B Weibel
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Saverio E Spagnolie
- Department of Mathematics, University of Wisconsin-Madison, 480 Lincoln Dr, Madison, WI 53706, USA
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, USA
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15
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ElGamel M, Vashistha H, Salman H, Mugler A. Multigenerational memory in bacterial size control. Phys Rev E 2023; 108:L032401. [PMID: 37849186 DOI: 10.1103/physreve.108.l032401] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/25/2023] [Indexed: 10/19/2023]
Abstract
Cells maintain a stable size as they grow and divide. Inspired by the available experimental data, most proposed models for size homeostasis assume size-control mechanisms that act on a timescale of one generation. Such mechanisms lead to short-lived autocorrelations in size fluctuations that decay within less than two generations. However, recent evidence from comparing sister lineages suggests that correlations in size fluctuations can persist for many generations. Here we develop a minimal model that explains these seemingly contradictory results. Our model proposes that different environments result in different control parameters, leading to distinct inheritance patterns. Multigenerational memory is revealed in constant environments but obscured when averaging over many different environments. Inferring the parameters of our model from Escherichia coli size data in microfluidic experiments, we recapitulate the observed statistics. Our paper elucidates the impact of the environment on cell homeostasis and growth and division dynamics.
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Affiliation(s)
- Motasem ElGamel
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
| | - Harsh Vashistha
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
| | - Hanna Salman
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
| | - Andrew Mugler
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
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16
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Fung HF, Bergmann DC. Function follows form: How cell size is harnessed for developmental decisions. Eur J Cell Biol 2023; 102:151312. [PMID: 36989838 DOI: 10.1016/j.ejcb.2023.151312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/16/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023] Open
Abstract
Cell size has profound effects on biological function, influencing a wide range of processes, including biosynthetic capacity, metabolism, and nutrient uptake. As a result, size is typically maintained within a narrow, population-specific range through size control mechanisms, which are an active area of study. While the physiological consequences of cell size are relatively well-characterized, less is known about its developmental consequences, and specifically its effects on developmental transitions. In this review, we compare systems where cell size is linked to developmental transitions, paying particular attention to examples from plants. We conclude by proposing that size can offer a simple readout of complex inputs, enabling flexible decisions during plant development.
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17
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Huang D, Johnson AE, Sim BS, Lo TW, Merrikh H, Wiggins PA. The in vivo measurement of replication fork velocity and pausing by lag-time analysis. Nat Commun 2023; 14:1762. [PMID: 36997519 PMCID: PMC10063678 DOI: 10.1038/s41467-023-37456-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 03/17/2023] [Indexed: 03/31/2023] Open
Abstract
AbstractAn important step towards understanding the mechanistic basis of the central dogma is the quantitative characterization of the dynamics of nucleic-acid-bound molecular motors in the context of the living cell. To capture these dynamics, we develop lag-time analysis, a method for measuring in vivo dynamics. Using this approach, we provide quantitative locus-specific measurements of fork velocity, in units of kilobases per second, as well as replisome pause durations, some with the precision of seconds. The measured fork velocity is observed to be both locus and time dependent, even in wild-type cells. In this work, we quantitatively characterize known phenomena, detect brief, locus-specific pauses at ribosomal DNA loci in wild-type cells, and observe temporal fork velocity oscillations in three highly-divergent bacterial species.
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18
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Cayron J, Dedieu-Berne A, Lesterlin C. Bacterial filaments recover by successive and accelerated asymmetric divisions that allow rapid post-stress cell proliferation. Mol Microbiol 2023; 119:237-251. [PMID: 36527185 DOI: 10.1111/mmi.15016] [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: 07/19/2022] [Revised: 12/09/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Filamentation is a reversible morphological change triggered in response to various stresses that bacteria might encounter in the environment, during host infection or antibiotic treatments. Here we re-visit the dynamics of filament formation and recovery using a consistent framework based on live-cells microscopy. We compare the fate of filamentous Escherichia coli induced by cephalexin that inhibits cell division or by UV-induced DNA-damage that additionally perturbs chromosome segregation. We show that both filament types recover by successive and accelerated rounds of divisions that preferentially occur at the filaments' tip, thus resulting in the rapid production of multiple daughter cells with tightly regulated size. The DNA content, viability and further division of the daughter cells essentially depends on the coordination between chromosome segregation and division within the mother filament. Septum positioning at the filaments' tip depends on the Min system, while the nucleoid occlusion protein SlmA regulates the timing of division to prevent septum closure on unsegregated chromosomes. Our results not only recapitulate earlier conclusions but provide a higher level of detail regarding filaments division and the fate of the daughter cells. Together with previous reports, this work uncovers how filamentation recovery allows for a rapid cell proliferation after stress treatment.
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Affiliation(s)
- Julien Cayron
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon, France
| | - Annick Dedieu-Berne
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon, France
| | - Christian Lesterlin
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon, France
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19
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Serbanescu D, Ojkic N, Banerjee S. Cellular resource allocation strategies for cell size and shape control in bacteria. FEBS J 2022; 289:7891-7906. [PMID: 34665933 PMCID: PMC9016100 DOI: 10.1111/febs.16234] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/21/2021] [Accepted: 10/18/2021] [Indexed: 01/14/2023]
Abstract
Bacteria are highly adaptive microorganisms that thrive in a wide range of growth conditions via changes in cell morphologies and macromolecular composition. How bacterial morphologies are regulated in diverse environmental conditions is a long-standing question. Regulation of cell size and shape implies control mechanisms that couple the growth and division of bacteria to their cellular environment and macromolecular composition. In the past decade, simple quantitative laws have emerged that connect cell growth to proteomic composition and the nutrient availability. However, the relationships between cell size, shape, and growth physiology remain challenging to disentangle and unifying models are lacking. In this review, we focus on regulatory models of cell size control that reveal the connections between bacterial cell morphology and growth physiology. In particular, we discuss how changes in nutrient conditions and translational perturbations regulate the cell size, growth rate, and proteome composition. Integrating quantitative models with experimental data, we identify the physiological principles of bacterial size regulation, and discuss the optimization strategies of cellular resource allocation for size control.
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Affiliation(s)
- Diana Serbanescu
- Department of Physics and Astronomy, University College London, UK
| | - Nikola Ojkic
- Department of Physics and Astronomy, University College London, UK
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20
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High-throughput determination of dry mass of single bacterial cells by ultrathin membrane resonators. Commun Biol 2022; 5:1227. [PMID: 36369276 PMCID: PMC9651879 DOI: 10.1038/s42003-022-04147-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 10/20/2022] [Indexed: 11/13/2022] Open
Abstract
How bacteria are able to maintain their size remains an open question. Techniques that can measure the biomass (dry mass) of single cells with high precision and high-throughput are demanded to elucidate this question. Here, we present a technological approach that combines the transport, guiding and focusing of individual bacteria from solution to the surface of an ultrathin silicon nitride membrane resonator in vacuum. The resonance frequencies of the membrane undergo abrupt variations at the instants where single cells land on the membrane surface. The resonator design displays a quasi-symmetric rectangular shape with an extraordinary capture area of 0.14 mm2, while maintaining a high mass resolution of 0.7 fg (1 fg = 10−15 g) to precisely resolve the dry mass of single cells. The small rectangularity of the membrane provides unprecedented frequency density of vibration modes that enables to retrieve the mass of individual cells with high accuracy by specially developed inverse problem theory. We apply this approach for profiling the dry mass distribution in Staphylococcus epidermidis and Escherichia coli cells. The technique allows the determination of the dry mass of single bacterial cells with an accuracy of about 1% at an unparalleled throughput of 20 cells/min. Finally, we revisit Koch & Schaechter model developed during 60 s to assess the intrinsic sources of stochasticity that originate cell size heterogeneity in steady-state populations. The results reveal the importance of mass resolution to correctly describe these mechanisms. A technological approach combines transport, guiding and focusing of individual bacteria from solution to ultrathin membrane resonators for dry mass determination of single cells with accuracy within 1% and throughput of 20 cells/min.
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21
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Berger M, Wolde PRT. Robust replication initiation from coupled homeostatic mechanisms. Nat Commun 2022; 13:6556. [PMID: 36344507 PMCID: PMC9640692 DOI: 10.1038/s41467-022-33886-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 10/05/2022] [Indexed: 11/09/2022] Open
Abstract
The bacterium Escherichia coli initiates replication once per cell cycle at a precise volume per origin and adds an on average constant volume between successive initiation events, independent of the initiation size. Yet, a molecular model that can explain these observations has been lacking. Experiments indicate that E. coli controls replication initiation via titration and activation of the initiator protein DnaA. Here, we study by mathematical modelling how these two mechanisms interact to generate robust replication-initiation cycles. We first show that a mechanism solely based on titration generates stable replication cycles at low growth rates, but inevitably causes premature reinitiation events at higher growth rates. In this regime, the DnaA activation switch becomes essential for stable replication initiation. Conversely, while the activation switch alone yields robust rhythms at high growth rates, titration can strongly enhance the stability of the switch at low growth rates. Our analysis thus predicts that both mechanisms together drive robust replication cycles at all growth rates. In addition, it reveals how an origin-density sensor yields adder correlations.
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Affiliation(s)
- Mareike Berger
- Biochemical Networks Group, Department of Information in Matter, AMOLF, 1098, XG, Amsterdam, The Netherlands
| | - Pieter Rein Ten Wolde
- Biochemical Networks Group, Department of Information in Matter, AMOLF, 1098, XG, Amsterdam, The Netherlands.
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22
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Feedback linking cell envelope stiffness, curvature, and synthesis enables robust rod-shaped bacterial growth. Proc Natl Acad Sci U S A 2022; 119:e2200728119. [PMID: 36191183 PMCID: PMC9564212 DOI: 10.1073/pnas.2200728119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial growth is remarkably robust to environmental fluctuations, yet the mechanisms of growth-rate homeostasis are poorly understood. Here, we combine theory and experiment to infer mechanisms by which Escherichia coli adapts its growth rate in response to changes in osmolarity, a fundamental physicochemical property of the environment. The central tenet of our theoretical model is that cell-envelope expansion is only sensitive to local information, such as enzyme concentrations, cell-envelope curvature, and mechanical strain in the envelope. We constrained this model with quantitative measurements of the dynamics of E. coli elongation rate and cell width after hyperosmotic shock. Our analysis demonstrated that adaptive cell-envelope softening is a key process underlying growth-rate homeostasis. Furthermore, our model correctly predicted that softening does not occur above a critical hyperosmotic shock magnitude and precisely recapitulated the elongation-rate dynamics in response to shocks with magnitude larger than this threshold. Finally, we found that, to coordinately achieve growth-rate and cell-width homeostasis, cells employ direct feedback between cell-envelope curvature and envelope expansion. In sum, our analysis points to cellular mechanisms of bacterial growth-rate homeostasis and provides a practical theoretical framework for understanding this process.
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23
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Knapp BD, Ward MD, Bowman GR, Shi H, Huang KC. Multiple conserved states characterize the twist landscape of the bacterial actin homolog MreB. Comput Struct Biotechnol J 2022; 20:5838-5846. [PMID: 36382191 PMCID: PMC9627593 DOI: 10.1016/j.csbj.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/03/2022] [Accepted: 10/03/2022] [Indexed: 12/01/2022] Open
Abstract
Filament formation by cytoskeletal proteins is critical to their involvement in myriad cellular processes. The bacterial actin homolog MreB, which is essential for cell-shape determination in many rod-shaped bacteria, has served as a model system for studying the mechanics of cytoskeletal filaments. Previous molecular dynamics (MD) simulations revealed that the twist of MreB double protofilaments is dependent on the bound nucleotide, as well as binding to the membrane or the accessory protein RodZ, and MreB mutations that modulate twist also affect MreB spatial organization and cell shape. Here, we show that MreB double protofilaments can adopt multiple twist states during microsecond-scale MD simulations. A deep learning algorithm trained only on high- and low-twist states robustly identified all twist conformations across most perturbations of ATP-bound MreB, suggesting the existence of a conserved set of states whose occupancy is affected by each perturbation to MreB. Simulations replacing ATP with ADP indicated that twist states were generally stable after hydrolysis. These findings suggest a rich twist landscape that could provide the capacity to tune MreB activity and therefore its effects on cell shape.
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Affiliation(s)
| | - Michael D. Ward
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63130, USA
- Center for the Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Gregory R. Bowman
- Department of Biochemistry & Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63130, USA
- Center for the Science and Engineering of Living Systems, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Handuo Shi
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kerwyn Casey Huang
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
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24
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Kitaguchi Y, Tei H, Uriu K. Cell size homeostasis under the circadian regulation of cell division in cyanobacteria. J Theor Biol 2022; 553:111260. [PMID: 36057343 DOI: 10.1016/j.jtbi.2022.111260] [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: 12/27/2021] [Revised: 06/10/2022] [Accepted: 08/18/2022] [Indexed: 10/31/2022]
Abstract
Bacterial cells maintain their characteristic cell size over many generations. Several rod-shaped bacteria, such as Escherichia coli and the cyanobacteria Synechococcus elongatus, divide after adding a constant length to their length at birth. Through this division control known as the adder mechanism, perturbation in cell length due to physiological fluctuation decays over generations at a rate of 2-1 per cell division. However, previous experiments have shown that the circadian clock in cyanobacteria reduces cell division frequency at a specific time of day under constant light. This circadian gating should modulate the division control by the adder mechanism, but its significance remains unknown. Here we address how the circadian gating affects cell length, doubling time, and cell length stability in cyanobacteria by using mathematical models. We show that a cell subject to circadian gating grows for a long time, and gives birth to elongated daughter cells. These elongated daughter cells grow faster than the previous generation, as elongation speed is proportional to cell length and divide in a short time before the next gating. Hence, the distributions of doubling time and cell length become bimodal, as observed in experimental data. Interestingly, the average doubling time over the population of cells is independent of gating because the extension of doubling time by gating is compensated by its reduction in the subsequent generation. On the other hand, average cell length is increased by gating, suggesting that the circadian clock controls cell length. We then show that the decay rate of perturbation in cell length depends on the ratio of delay in division by the gating τG to the average doubling time τ0 as [Formula: see text] . We estimated τG≈2.5, τ0≈13.6 hours, and τG/τ0≈0.18 from experimental data, indicating that a long doubling time in cyanobacteria maintains the decay rate similar to that of the adder mechanism. Thus, our analysis suggests that the acquisition of the circadian clock during evolution did not impose a constraint on cell size homeostasis in cyanobacteria.
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Affiliation(s)
- Yuta Kitaguchi
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1129, Japan.
| | - Hajime Tei
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1129, Japan
| | - Koichiro Uriu
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1129, Japan
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25
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Cadart C, Heald R. Scaling of biosynthesis and metabolism with cell size. Mol Biol Cell 2022; 33:pe5. [PMID: 35862496 PMCID: PMC9582640 DOI: 10.1091/mbc.e21-12-0627] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 11/17/2022] Open
Abstract
Cells adopt a size that is optimal for their function, and pushing them beyond this limit can cause cell aging and death by senescence or reduce proliferative potential. However, by increasing their genome copy number (ploidy), cells can increase their size dramatically and homeostatically maintain physiological properties such as biosynthesis rate. Recent studies investigating the relationship between cell size and rates of biosynthesis and metabolism under normal, polyploid, and pathological conditions are revealing new insights into how cells attain the best function or fitness for their size by tuning processes including transcription, translation, and mitochondrial respiration. A new frontier is to connect single-cell scaling relationships with tissue and whole-organism physiology, which promises to reveal molecular and evolutionary principles underlying the astonishing diversity of size observed across the tree of life.
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Affiliation(s)
- Clotilde Cadart
- Molecular and Cell Biology Department, University of California, Berkeley, Berkeley, CA 94720-3200
| | - Rebecca Heald
- Molecular and Cell Biology Department, University of California, Berkeley, Berkeley, CA 94720-3200
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26
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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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27
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Changes in body shape implicate cuticle stretch in C. elegans growth control. Cells Dev 2022; 170:203780. [DOI: 10.1016/j.cdev.2022.203780] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/21/2022] [Accepted: 04/12/2022] [Indexed: 11/23/2022]
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28
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Coupling between DNA replication, segregation, and the onset of constriction in Escherichia coli. Cell Rep 2022; 38:110539. [PMID: 35320717 PMCID: PMC9003928 DOI: 10.1016/j.celrep.2022.110539] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 10/01/2021] [Accepted: 02/25/2022] [Indexed: 11/24/2022] Open
Abstract
Escherichia coli cell cycle features two critical cell-cycle checkpoints: initiation of replication and the onset of constriction. While the initiation of DNA replication has been extensively studied, it is less clear what triggers the onset of constriction and when exactly it occurs during the cell cycle. Here, using high-throughput fluorescence microscopy in microfluidic devices, we determine the timing for the onset of constriction relative to the replication cycle in different growth rates. Our single-cell data and modeling indicate that the initiation of constriction is coupled to replication-related processes in slow growth conditions. Furthermore, our data suggest that this coupling involves the mid-cell chromosome blocking the onset of constriction via some form of nucleoid occlusion occurring independently of SlmA and the Ter linkage proteins. This work highlights the coupling between replication and division cycles and brings up a new nucleoid mediated control mechanism in E. coli. Using high-throughput microscopy, Tiruvadi-Krishnan et al. determine timings for critical cell-cycle checkpoints related to division and replication in Escherichia coli. The data, combined with cell-cycle modeling, show that the onset of constriction is blocked by the mid-cell nucleoid. In slow-growth conditions, the blockage is limiting for cell division.
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29
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Ithurbide S, Gribaldo S, Albers SV, Pende N. Spotlight on FtsZ-based cell division in Archaea. Trends Microbiol 2022; 30:665-678. [PMID: 35246355 DOI: 10.1016/j.tim.2022.01.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 12/22/2021] [Accepted: 01/10/2022] [Indexed: 12/15/2022]
Abstract
Compared with the extensive knowledge on cell division in model eukaryotes and bacteria, little is known about how archaea divide. Interestingly, both endosomal sorting complex required for transport (ESCRT)-based and FtsZ-based cell division systems are found in members of the Archaea. In the past couple of years, several studies have started to shed light on FtsZ-based cell division processes in members of the Euryarchaeota. In this review we highlight recent findings in this emerging field of research. We present current knowledge of the cell division machinery of halophiles which relies on two FtsZ proteins, and we compare it with that of methanobacteria, which relies on only one FtsZ. Finally, we discuss how these differences relate to the distinct cell envelopes of these two archaeal model systems.
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Affiliation(s)
- Solenne Ithurbide
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Simonetta Gribaldo
- Evolutionary Biology of the Microbial Cell Unit, CNRS UMR2001, Department of Microbiology, Institut Pasteur, Paris, France.
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.
| | - Nika Pende
- Evolutionary Biology of the Microbial Cell Unit, CNRS UMR2001, Department of Microbiology, Institut Pasteur, Paris, France
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30
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Stawsky A, Vashistha H, Salman H, Brenner N. Multiple timescales in bacterial growth homeostasis. iScience 2022; 25:103678. [PMID: 35118352 PMCID: PMC8792075 DOI: 10.1016/j.isci.2021.103678] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 10/30/2021] [Accepted: 12/21/2021] [Indexed: 01/12/2023] Open
Abstract
In balanced exponential growth, bacteria maintain many properties statistically stable for a long time: cell size, cell cycle time, and more. As these are strongly coupled variables, it is not a-priori obvious which are directly regulated and which are stabilized through interactions. Here, we address this problem by separating timescales in bacterial single-cell dynamics. Disentangling homeostatic set points from fluctuations around them reveals that some variables, such as growth-rate, cell size and cycle time, are "sloppy" with highly volatile set points. Quantifying the relative contribution of environmental and internal sources, we find that sloppiness is primarily driven by the environment. Other variables such as fold-change define "stiff" combinations of coupled variables with robust set points. These results are manifested geometrically as a control manifold in the space of variables: set points span a wide range of values within the manifold, whereas out-of-manifold deviations are constrained. Our work offers a generalizable data-driven approach for identifying control variables in a multidimensional system.
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Affiliation(s)
- Alejandro Stawsky
- Interdisciplinary Program in Applied Mathematics, Technion, Haifa, Israel
- Network Biology Research Laboratories, Technion, Haifa, Israel
| | - Harsh Vashistha
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Hanna Salman
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Naama Brenner
- Network Biology Research Laboratories, Technion, Haifa, Israel
- Department of Chemical Engineering, Technion, Haifa, Israel
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31
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Goodman MB, Savage-Dunn C. Reciprocal interactions between transforming growth factor beta signaling and collagens: Insights from Caenorhabditis elegans. Dev Dyn 2022; 251:47-60. [PMID: 34537996 PMCID: PMC8982858 DOI: 10.1002/dvdy.423] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 01/03/2023] Open
Abstract
Studies in genetically tractable organisms such as the nematode Caenorhabditis elegans have led to pioneering insights into conserved developmental regulatory mechanisms. For example, Smad signal transducers for the transforming growth factor beta (TGF-β) superfamily were first identified in C. elegans and in the fruit fly Drosophila. Recent studies of TGF-β signaling and the extracellular matrix (ECM) in C. elegans have forged unexpected links between signaling and the ECM, yielding novel insights into the reciprocal interactions that occur across tissues and spatial scales, and potentially providing new opportunities for the study of biomechanical regulation of gene expression.
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Affiliation(s)
- Miriam B. Goodman
- Department of Molecular and Cellular Physiology, Stanford University, CA 94304
| | - Cathy Savage-Dunn
- Department of Biology, Queens College at the City University of New York, 11367,Correspondence to: >
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32
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Sassi AS, Garcia-Alcala M, Aldana M, Tu Y. Protein concentration fluctuations in the high expression regime: Taylor's law and its mechanistic origin. PHYSICAL REVIEW. X 2022; 12:011051. [PMID: 35756903 PMCID: PMC9233241 DOI: 10.1103/physrevx.12.011051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Protein concentration in a living cell fluctuates over time due to noise in growth and division processes. In the high expression regime, variance of the protein concentration in a cell was found to scale with the square of the mean, which belongs to a general phenomenon called Taylor's law (TL). To understand the origin for these fluctuations, we measured protein concentration dynamics in single E. coli cells from a set of strains with a variable expression of fluorescent proteins. The protein expression is controlled by a set of constitutive promoters with different strength, which allows to change the expression level over 2 orders of magnitude without introducing noise from fluctuations in transcription regulators. Our data confirms the square TL, but the prefactor A has a cell-to-cell variation independent of the promoter strength. Distributions of the normalized protein concentration for different promoters are found to collapse onto the same curve. To explain these observations, we used a minimal mechanistic model to describe the stochastic growth and division processes in a single cell with a feedback mechanism for regulating cell division. In the high expression regime where extrinsic noise dominates, the model reproduces our experimental results quantitatively. By using a mean-field approximation in the minimal model, we showed that the stochastic dynamics of protein concentration is described by a Langevin equation with multiplicative noise. The Langevin equation has a scale invariance which is responsible for the square TL. By solving the Langevin equation, we obtained an analytical solution for the protein concentration distribution function that agrees with experiments. The solution shows explicitly how the prefactor A depends on strength of different noise sources, which explains its cell-to-cell variability. By using this approach to analyze our single-cell data, we found that the noise in production rate dominates the noise from cell division. The deviation from the square TL in the low expression regime can also be captured in our model by including intrinsic noise in the production rate.
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Affiliation(s)
| | - Mayra Garcia-Alcala
- Department of Molecular and Cellular Biology, John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
| | - Maximino Aldana
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos 62210, México
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Yuhai Tu
- IBM T.J. Watson Research Center, Yorktown Heights, NY 10598, U.S.A
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33
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Huang D, Lo T, Merrikh H, Wiggins PA. Characterizing stochastic cell-cycle dynamics in exponential growth. Phys Rev E 2022; 105:014420. [PMID: 35193317 PMCID: PMC9506121 DOI: 10.1103/physreve.105.014420] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Two powerful and complementary experimental approaches are commonly used to study the cell cycle and cell biology: One class of experiments characterizes the statistics (or demographics) of an unsynchronized exponentially growing population, while the other captures cell-cycle dynamics, either by time-lapse imaging of full cell cycles or in bulk experiments on synchronized populations. In this paper, we study the subtle relationship between observations in these two distinct experimental approaches. We begin with an existing model: A single-cell deterministic description of cell-cycle dynamics where cell states (i.e., periods or phases) have precise lifetimes. We then generalize this description to a stochastic model in which the states have stochastic lifetimes, as described by arbitrary probability distribution functions. Our analyses of the demographics of an exponential culture reveal a simple and exact correspondence between the deterministic and stochastic models: The corresponding state ages in the deterministic model are equal to the exponential mean of the age in the stochastic model. An important implication is therefore that the demographics of an exponential culture will be well fit by a deterministic model even if the state timing is stochastic. Although we explore the implications of the models in the context of the Escherichia coli cell cycle, we expect both the models as well as the significance of the exponential-mean lifetimes to find many applications in the quantitative analysis of cell-cycle dynamics in other biological systems.
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Affiliation(s)
- Dean Huang
- Department of Physics, University of Washington, Seattle, WA, 98195
| | - Teresa Lo
- Department of Physics, University of Washington, Seattle, WA, 98195
| | - Houra Merrikh
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37205
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37232
| | - Paul A. Wiggins
- Department of Physics, University of Washington, Seattle, WA, 98195
- Department of Bioengineering, University of Washington, Seattle, WA, 98195
- Department of Microbiology, University of Washington, Seattle, WA, 98195
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34
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Kar P, Tiruvadi-Krishnan S, Männik J, Männik J, Amir A. Distinguishing different modes of growth using single-cell data. eLife 2021; 10:72565. [PMID: 34854811 PMCID: PMC8727026 DOI: 10.7554/elife.72565] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 11/21/2021] [Indexed: 12/21/2022] Open
Abstract
Collection of high-throughput data has become prevalent in biology. Large datasets allow the use of statistical constructs such as binning and linear regression to quantify relationships between variables and hypothesize underlying biological mechanisms based on it. We discuss several such examples in relation to single-cell data and cellular growth. In particular, we show instances where what appears to be ordinary use of these statistical methods leads to incorrect conclusions such as growth being non-exponential as opposed to exponential and vice versa. We propose that the data analysis and its interpretation should be done in the context of a generative model, if possible. In this way, the statistical methods can be validated either analytically or against synthetic data generated via the use of the model, leading to a consistent method for inferring biological mechanisms from data. On applying the validated methods of data analysis to infer cellular growth on our experimental data, we find the growth of length in E. coli to be non-exponential. Our analysis shows that in the later stages of the cell cycle the growth rate is faster than exponential.
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Affiliation(s)
- Prathitha Kar
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States.,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, United States
| | | | - Jaana Männik
- Department of Physics and Astronomy, University of Tennessee, Knoxville, United States
| | - Jaan Männik
- Department of Physics and Astronomy, University of Tennessee, Knoxville, United States
| | - Ariel Amir
- Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, United States
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35
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Westoby M, Nielsen DA, Gillings MR, Gumerov VM, Madin JS, Paulsen IT, Tetu SG. Strategic traits of bacteria and archaea vary widely within substrate-use groups. FEMS Microbiol Ecol 2021; 97:6402898. [PMID: 34665251 DOI: 10.1093/femsec/fiab142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/14/2021] [Indexed: 11/12/2022] Open
Abstract
Quantitative traits such as maximum growth rate and cell radial diameter are one facet of ecological strategy variation across bacteria and archaea. Another facet is substrate-use pathways, such as iron reduction or methylotrophy. Here, we ask how these two facets intersect, using a large compilation of data for culturable species and examining seven quantitative traits (genome size, signal transduction protein count, histidine kinase count, growth temperature, temperature-adjusted maximum growth rate, cell radial diameter and 16S rRNA operon copy number). Overall, quantitative trait variation within groups of organisms possessing a particular substrate-use pathway was very broad, outweighing differences between substrate-use groups. Although some substrate-use groups had significantly different means for some quantitative traits, standard deviation of quantitative trait values within each substrate-use pathway mostly averaged between 1.6 and 1.8 times larger than standard deviation across group means. Most likely, this wide variation reflects ecological strategy: for example, fast maximum growth rate is likely to express an early successional or copiotrophic strategy, and maximum growth varies widely within most substrate-use pathways. In general, it appears that these quantitative traits express different and complementary information about ecological strategy, compared with substrate use.
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Affiliation(s)
- Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2019, Australia
| | - Daniel A Nielsen
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2019, Australia
| | - Michae R Gillings
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2019, Australia
| | - Vadim M Gumerov
- Department of Microbiology, Ohio State University, 318 W. 12th Avenue, Columbus, OH 43210, USA
| | - Joshua S Madin
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA
| | - Ian T Paulsen
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2019, Australia
| | - Sasha G Tetu
- Department of Molecular Sciences, Macquarie University, Sydney, NSW 2019, Australia
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36
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Briggs NS, Bruce KE, Naskar S, Winkler ME, Roper DI. The Pneumococcal Divisome: Dynamic Control of Streptococcus pneumoniae Cell Division. Front Microbiol 2021; 12:737396. [PMID: 34737730 PMCID: PMC8563077 DOI: 10.3389/fmicb.2021.737396] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/15/2021] [Indexed: 12/14/2022] Open
Abstract
Cell division in Streptococcus pneumoniae (pneumococcus) is performed and regulated by a protein complex consisting of at least 14 different protein elements; known as the divisome. Recent findings have advanced our understanding of the molecular events surrounding this process and have provided new understanding of the mechanisms that occur during the division of pneumococcus. This review will provide an overview of the key protein complexes and how they are involved in cell division. We will discuss the interaction of proteins in the divisome complex that underpin the control mechanisms for cell division and cell wall synthesis and remodelling that are required in S. pneumoniae, including the involvement of virulence factors and capsular polysaccharides.
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Affiliation(s)
- Nicholas S. Briggs
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Kevin E. Bruce
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - Souvik Naskar
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, IN, United States
| | - David I. Roper
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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37
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Hu L, Rech J, Bouet JY, Liu J. Spatial control over near-critical-point operation ensures fidelity of ParABS-mediated DNA partition. Biophys J 2021; 120:3911-3924. [PMID: 34418367 PMCID: PMC8511131 DOI: 10.1016/j.bpj.2021.08.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/26/2021] [Accepted: 08/13/2021] [Indexed: 01/20/2023] Open
Abstract
In bacteria, most low-copy-number plasmid and chromosomally encoded partition systems belong to the tripartite ParABS partition machinery. Despite the importance in genetic inheritance, the mechanisms of ParABS-mediated genome partition are not well understood. Combining theory and experiment, we provided evidence that the ParABS system-DNA partitioning in vivo via the ParA-gradient-based Brownian ratcheting-operates near a transition point in parameter space (i.e., a critical point), across which the system displays qualitatively different motile behaviors. This near-critical-point operation adapts the segregation distance of replicated plasmids to the half length of the elongating nucleoid, ensuring both cell halves to inherit one copy of the plasmids. Further, we demonstrated that the plasmid localizes the cytoplasmic ParA to buffer the partition fidelity against the large cell-to-cell fluctuations in ParA level. The spatial control over the near-critical-point operation not only ensures both sensitive adaptation and robust execution of partitioning but also sheds light on the fundamental question in cell biology: how do cells faithfully measure cellular-scale distance by only using molecular-scale interactions?
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Affiliation(s)
- Longhua Hu
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jérôme Rech
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Intégrative, Centre National de la Recherche Scientifique, Université de Toulouse, UPS, Toulouse, France
| | - Jean-Yves Bouet
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie Intégrative, Centre National de la Recherche Scientifique, Université de Toulouse, UPS, Toulouse, France.
| | - Jian Liu
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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38
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Zhong J, Liang M, Ai Y. Submicron-precision particle characterization in microfluidic impedance cytometry with double differential electrodes. LAB ON A CHIP 2021; 21:2869-2880. [PMID: 34236057 DOI: 10.1039/d1lc00481f] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Submicron-precision particle characterization is crucial for counting, sizing and identifying a variety of biological particles, such as bacteria and apoptotic bodies. Microfluidic impedance cytometry has been attractive in current research for microparticle characterization due to its advantages of label-free detection, ease of miniaturization and affordability. However, conventional electrode configurations of three electrodes and floating electrodes have not yet demonstrated the capability of probing submicron particles or microparticles with a submicron size difference. In this study, we present a label-free high-throughput (∼800 particles per second) impedance-based microfluidic flow cytometry system integrated with a novel design of a double differential electrode configuration, enabling submicron particle detection (down to 0.4 μm) with a minimum size resolution of 200 nm. The signal-to-noise ratio has been boosted from 13.98 dB to 32.64 dB compared to a typical three-electrode configuration. With the proposed microfluidic impedance cytometry, we have shown results of sizing microparticles that accurately correlate with manufacturers' datasheets (R2 = 0.99938). It also shows that population ratios of differently sized beads in mixture samples are consistent with the results given by commercial fluorescence-based flow cytometry (within ∼1% difference). This work provides a label-free approach with submicron precision for sizing and counting microscale and submicron particles, and a new avenue of designing electrode configurations with a feature of suppressing the electrical noise for accomplishing a high signal-to-noise ratio in a wide range of frequencies. This novel double differential impedance sensing system paves a new pathway for real-time analysis and accurate particle screening in pathological and pharmacological research.
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Affiliation(s)
- Jianwei Zhong
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
| | - Minhui Liang
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
| | - Ye Ai
- Pillar of Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
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39
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Robust surface-to-mass coupling and turgor-dependent cell width determine bacterial dry-mass density. Proc Natl Acad Sci U S A 2021; 118:2021416118. [PMID: 34341116 PMCID: PMC8364103 DOI: 10.1073/pnas.2021416118] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Intracellular biomass density is an important variable for cellular physiology. It defines the crowded state of the cytoplasm and thus influences macromolecular interactions and transport. To control density during growth, bacteria must expand their cell volumes in synchrony with biomass. The regulation of volume growth and biomass density remain fundamentally not understood—in bacteria or any other organism. Using advanced microscopy, we demonstrate that cells control dry-mass density indirectly through two independent processes. First, cells expand surface area, rather than volume, in proportion with biomass growth. Second, cell width is controlled independently, with an important influence of turgor pressure. Our findings overturn a long-standing paradigm of mass-density constancy in bacteria and reveal fundamental determinants of dry-mass density and shape. During growth, cells must expand their cell volumes in coordination with biomass to control the level of cytoplasmic macromolecular crowding. Dry-mass density, the average ratio of dry mass to volume, is roughly constant between different nutrient conditions in bacteria, but it remains unknown whether cells maintain dry-mass density constant at the single-cell level and during nonsteady conditions. Furthermore, the regulation of dry-mass density is fundamentally not understood in any organism. Using quantitative phase microscopy and an advanced image-analysis pipeline, we measured absolute single-cell mass and shape of the model organisms Escherichia coli and Caulobacter crescentus with improved precision and accuracy. We found that cells control dry-mass density indirectly by expanding their surface, rather than volume, in direct proportion to biomass growth—according to an empirical surface growth law. At the same time, cell width is controlled independently. Therefore, cellular dry-mass density varies systematically with cell shape, both during the cell cycle or after nutrient shifts, while the surface-to-mass ratio remains nearly constant on the generation time scale. Transient deviations from constancy during nutrient shifts can be reconciled with turgor-pressure variations and the resulting elastic changes in surface area. Finally, we find that plastic changes of cell width after nutrient shifts are likely driven by turgor variations, demonstrating an important regulatory role of mechanical forces for width regulation. In conclusion, turgor-dependent cell width and a slowly varying surface-to-mass coupling constant are the independent variables that determine dry-mass density.
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40
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Abstract
Bacterial cell division, with a few exceptions, is driven by FtsZ through a treadmilling mechanism to remodel and constrict the rigid peptidoglycan (PG) layer. Yet different organisms may differ in the composition of the cell division complex (divisome). In the filamentous cyanobacterium Anabaena sp. strain PCC 7120, hetF is required for the initiation of the differentiation of heterocysts, cells specialized in N2 fixation under combined-nitrogen deprivation. In this study, we demonstrate that hetF is expressed in vegetative cells and necessary for cell division under certain conditions. Under nonpermissive conditions, cells of a ΔhetF mutant stop dividing, consistent with increased levels of HetF under similar conditions in the wild type. Furthermore, HetF is a membrane protein located at midcell and cell-cell junctions. In the absence of HetF, FtsZ rings are still present in the elongated cells; however, PG remodeling is abolished. This phenotype is similar to that observed with the inhibition of the septal PG synthase FtsI. We further reveal that HetF is recruited to or stabilized at the divisome by interacting with FtsI and that this interaction is necessary for HetF function in cell division. Our results indicate that HetF is a member of the divisome depending mainly on light intensity and reveal distinct features of the cell division machinery in cyanobacteria that are of high ecological and environmental importance.
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41
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Tanaka M, Kitanishi-Yumura T, Yumura S. A 'dynamic adder model' for cell size homeostasis in Dictyostelium cells. Sci Rep 2021; 11:13742. [PMID: 34215778 PMCID: PMC8253765 DOI: 10.1038/s41598-021-92700-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 06/15/2021] [Indexed: 02/06/2023] Open
Abstract
After a cell divides into two daughter cells, the total cell surface area of the daughter cells should increase to the original size to maintain cell size homeostasis in a single cell cycle. Previously, three models have been proposed to explain the regulation of cell size homeostasis: sizer, timer, and adder models. Here, we precisely measured the total cell surface area of Dictyostelium cells in a whole cell cycle by using the agar-overlay method, which eliminated the influence of surface membrane reservoirs, such as microvilli and membrane wrinkles. The total cell surface area exponentially increased during interphase, slightly decreased at metaphase, and then increased by approximately 20% during cytokinesis. From the analysis of the added surface area, we concluded that the cell size was regulated by the adder or near-adder model in interphase. This adder model is not caused by a simple cell membrane addition, but is more dynamic due to the rapid cell membrane turnover. We propose a 'dynamic adder model' to explain cell size homeostasis in interphase.
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Affiliation(s)
- Masahito Tanaka
- grid.268397.10000 0001 0660 7960Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, 753-8512 Japan ,grid.288127.60000 0004 0466 9350Present Address: Laboratory of Physics and Cell Biology, Department of Chromosome Science, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540 Japan
| | - Toshiko Kitanishi-Yumura
- grid.268397.10000 0001 0660 7960Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, 753-8512 Japan
| | - Shigehiko Yumura
- grid.268397.10000 0001 0660 7960Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, 753-8512 Japan
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42
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Effects of PatU3 Peptides on Cell Size and Heterocyst Frequency of Anabaena sp. Strain PCC 7120. J Bacteriol 2021; 203:e0010821. [PMID: 33846118 DOI: 10.1128/jb.00108-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
patU, one of the genes specifically found in filamentous cyanobacteria, is required for the pattern formation in heterocyst-forming species. In Anabaena sp. strain PCC 7120, patU is split into patU5 and patU3, and only patU3 is involved in heterocyst patterning. Here, we report that PatU3 is also involved in control of cell size. A patU3 deletion mutant showed remarkably smaller cell size and much higher heterocyst frequency than the wild type. Yeast two-hybrid and pulldown assays demonstrated a direct interaction between PatU3 and the cell division protein Ftn6. Without the N-terminal 16-amino-acid (aa) portion (MQERFQAVIKRRLQIH [the identified octapeptide is underlined]), PatU3 was no longer able to interact with Ftn6. This portion of PatU3 is also required for the interaction with PatN, a protein related to heterocyst differentiation/patterning. Addition of the 16-aa peptide or AVIKRRLQ-containing peptides restored the cell size and heterocyst frequency of a patU3 deletion mutant to normal or nearly wild-type levels. PatU3(1-16aa)-GFP, the N-terminal 16-aa sequence fused with green fluorescent protein (GFP), formed polar aggregates and peripheral patches in heterocysts of Anabaena sp. strain PCC 7120, whereas PatU3(1-198aa)-GFP showed a homogeneous distribution in the cytoplasm of all cells. The N-terminal AVIKRRLQ-containing sequence may function in intact PatU3, as a separate peptide, or both. IMPORTANCE PatU (or split into PatU5 and PatU3) is distributed in almost all filamentous cyanobacteria, including those that do not form heterocysts (except Pseudanabaena); however, its functions other than heterocyst differentiation/patterning have not been reported before. In this study, we found that PatU3 in Anabaena sp. strain PCC 7120 is involved in cell size determination. The N-terminal 16-aa sequence of PatU3 is required for the control of cell size and interaction with the cell division protein Ftn6, and an octapeptide (aa 7 to aa 14) within the 16-aa sequence can restore the cell size (and heterocyst frequency) of a patU3 deletion mutant to normal. Such a peptide, if generated from PatU or PatU3 in vivo, may promote intercellular coordination in filamentous cyanobacteria.
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Limits and Constraints on Mechanisms of Cell-Cycle Regulation Imposed by Cell Size-Homeostasis Measurements. Cell Rep 2021; 32:107992. [PMID: 32783950 DOI: 10.1016/j.celrep.2020.107992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 04/09/2020] [Accepted: 07/13/2020] [Indexed: 01/27/2023] Open
Abstract
High-throughput imaging has led to an explosion of observations about cell-size homeostasis across the kingdoms of life. Among bacteria, "adder" behavior-in which a constant size increment appears to be added during each cell cycle-is ubiquitous, while various eukaryotes show other size-homeostasis behaviors. Since interactions between cell-cycle progression and growth ultimately determine such behaviors, we developed a general model of cell-cycle regulation. Our analyses reveal a range of scenarios that are plausible but fail to regulate cell size, indicating that mechanisms of cell-cycle regulation are stringently limited by size-control requirements, and possibly why certain cell-cycle features are strongly conserved. Cell-cycle features can play unintuitive roles in altering size-homeostasis behaviors: noisy regulator production can enhance adder behavior, while Whi5-like inhibitor dilutors respond sensitively to perturbations to G2/M control and noisy G1/S checkpoints. Our model thus provides holistic insights into the mechanistic implications of size-homeostasis experimental measurements.
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Pandey PP, Singh H, Jain S. Exponential trajectories, cell size fluctuations, and the adder property in bacteria follow from simple chemical dynamics and division control. Phys Rev E 2021; 101:062406. [PMID: 32688579 DOI: 10.1103/physreve.101.062406] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/03/2020] [Indexed: 02/03/2023]
Abstract
Experiments on steady-state bacterial cultures have uncovered several quantitative regularities at the system level. These include, first, the exponential growth of cell size with time and the balanced growth of intracellular chemicals between cell birth and division, which are puzzling given the nonlinear and decentralized chemical dynamics in the cell. We model a cell as a set of chemical populations undergoing nonlinear mass action kinetics in a container whose volume is a linear function of the chemical populations. This turns out to be a special class of dynamical systems that generically has attractors in which all populations grow exponentially with time at the same rate. This explains exponential balanced growth of bacterial cells without invoking any regulatory mechanisms and suggests that this could be a robust property of protocells as well. Second, we consider the hypothesis that cells commit themselves to division when a certain internal chemical population reaches a threshold of N molecules. We show that this hypothesis leads to a simple explanation of some of the variability observed across cells in a bacterial culture. In particular, it reproduces the adder property of cell size fluctuations observed recently in E. coli; the observed correlations among interdivision time, birth volume, and added volume in a generation; and the observed scale of the fluctuations (CV ≈ 10-30%) when N is between 10 and 100. Third, upon including a suitable regulatory mechanism that optimizes the growth rate of the cell, the model reproduces the observed bacterial growth laws including the dependence of the growth rate and ribosomal protein fraction on the medium. Thus, the models provide a framework for unifying diverse aspects of bacterial growth physiology under one roof. They also suggest new questions for experimental and theoretical enquiry.
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Affiliation(s)
- Parth Pratim Pandey
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
| | - Harshant Singh
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
| | - Sanjay Jain
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India.,Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, New Mexico 87501, USA
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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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46
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Westoby M, Gillings MR, Madin JS, Nielsen DA, Paulsen IT, Tetu SG. Trait dimensions in bacteria and archaea compared to vascular plants. Ecol Lett 2021; 24:1487-1504. [PMID: 33896087 DOI: 10.1111/ele.13742] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 02/25/2021] [Accepted: 03/04/2021] [Indexed: 01/04/2023]
Abstract
Bacteria and archaea have very different ecology compared to plants. One similarity, though, is that much discussion of their ecological strategies has invoked concepts such as oligotrophy or stress tolerance. For plants, so-called 'trait ecology'-strategy description reframed along measurable trait dimensions-has made global syntheses possible. Among widely measured trait dimensions for bacteria and archaea three main axes are evident. Maximum growth rate in association with rRNA operon copy number expresses a rate-yield trade-off that is analogous to the acquisitive-conservative spectrum in plants, though underpinned by different trade-offs. Genome size in association with signal transduction expresses versatility. Cell size has influence on diffusive uptake and on relative wall costs. These trait dimensions, and potentially others, offer promise for interpreting ecology. At the same time, there are very substantial differences from plant trait ecology. Traits and their underpinning trade-offs are different. Also, bacteria and archaea use a variety of different substrates. Bacterial strategies can be viewed both through the facet of substrate-use pathways, and also through the facet of quantitative traits such as maximum growth rate. Preliminary evidence shows the quantitative traits vary widely within substrate-use pathways. This indicates they convey information complementary to substrate use.
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Affiliation(s)
- Mark Westoby
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Michael R Gillings
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Joshua S Madin
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI, USA
| | - Daniel A Nielsen
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Ian T Paulsen
- Dept of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sasha G Tetu
- Dept of Molecular Sciences, Macquarie University, Sydney, NSW, Australia
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47
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Meunier A, Cornet F, Campos M. Bacterial cell proliferation: from molecules to cells. FEMS Microbiol Rev 2021; 45:fuaa046. [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] [MESH Headings] [Grants] [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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48
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Noh MH, Cha S, Kim M, Jung GY. Recent Advances in Microbial Cell Growth Regulation Strategies for Metabolic Engineering. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0511-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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49
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Vasdekis AE, Singh A. Microbial metabolic noise. WIREs Mech Dis 2020; 13:e1512. [PMID: 33225608 DOI: 10.1002/wsbm.1512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 09/23/2020] [Accepted: 10/26/2020] [Indexed: 11/06/2022]
Abstract
From the time a cell was first placed under the microscope, it became apparent that identifying two clonal cells that "look" identical is extremely challenging. Since then, cell-to-cell differences in shape, size, and protein content have been carefully examined, informing us of the ultimate limits that hinder two cells from occupying an identical phenotypic state. Here, we present recent experimental and computational evidence that similar limits emerge also in cellular metabolism. These limits pertain to stochastic metabolic dynamics and, thus, cell-to-cell metabolic variability, including the resulting adapting benefits. We review these phenomena with a focus on microbial metabolism and conclude with a brief outlook on the potential relationship between metabolic noise and adaptive evolution. This article is categorized under: Metabolic Diseases > Computational Models Metabolic Diseases > Biomedical Engineering.
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Affiliation(s)
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, USA
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50
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Ding Q, Diao W, Gao C, Chen X, Liu L. Microbial cell engineering to improve cellular synthetic capacity. Biotechnol Adv 2020; 45:107649. [PMID: 33091485 DOI: 10.1016/j.biotechadv.2020.107649] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/02/2020] [Accepted: 10/13/2020] [Indexed: 01/21/2023]
Abstract
Rapid technological progress in gene assembly, biosensors, and genetic circuits has led to reinforce the cellular synthetic capacity for chemical production. However, overcoming the current limitations of these techniques in maintaining cellular functions and enhancing the cellular synthetic capacity (e.g., catalytic efficiency, strain performance, and cell-cell communication) remains challenging. In this review, we propose a strategy for microbial cell engineering to improve the cellular synthetic capacity by utilizing biotechnological tools along with system biology methods to regulate cellular functions during chemical production. Current strategies in microbial cell engineering are mainly focused on the organelle, cell, and consortium levels. This review highlights the potential of using biotechnology to further develop the field of microbial cell engineering and provides guidance for utilizing microorganisms as attractive regulation targets.
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Affiliation(s)
- Qiang Ding
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Wenwen Diao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
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