1
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Cheong JH, Qiu X, Liu Y, Krach E, Guo Y, Bhusal S, Schüttler HB, Arnold J, Mao L. The clock in growing hyphae and their synchronization in Neurospora crassa. Commun Biol 2024; 7:735. [PMID: 38890525 PMCID: PMC11189396 DOI: 10.1038/s42003-024-06429-6] [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: 04/26/2023] [Accepted: 06/07/2024] [Indexed: 06/20/2024] Open
Abstract
Utilizing a microfluidic chip with serpentine channels, we inoculated the chip with an agar plug with Neurospora crassa mycelium and successfully captured individual hyphae in channels. For the first time, we report the presence of an autonomous clock in hyphae. Fluorescence of a mCherry reporter gene driven by a clock-controlled gene-2 promoter (ccg-2p) was measured simultaneously along hyphae every half an hour for at least 6 days. We entrained single hyphae to light over a wide range of day lengths, including 6,12, 24, and 36 h days. Hyphae tracked in individual serpentine channels were highly synchronized (K = 0.60-0.78). Furthermore, hyphae also displayed temperature compensation properties, where the oscillation period was stable over a physiological range of temperatures from 24 °C to 30 °C (Q10 = 1.00-1.10). A Clock Tube Model developed could mimic hyphal growth observed in the serpentine chip and provides a mechanism for the stable banding patterns seen in race tubes at the macroscopic scale and synchronization through molecules riding the growth wave in the device.
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Affiliation(s)
- Jia Hwei Cheong
- Chemistry Department, University of Georgia, Athens, GA, 30602, USA
| | - Xiao Qiu
- Institute of Bioinformatics, University of Georgia, Athens, GA, 30602, USA
| | - Yang Liu
- Chemistry Department, University of Georgia, Athens, GA, 30602, USA
| | - Emily Krach
- Genetics Department, University of Georgia, Athens, GA, 30602, USA
| | - Yinping Guo
- Genetics Department, University of Georgia, Athens, GA, 30602, USA
| | - Shishir Bhusal
- Department of Physics and Astronomy, University of Georgia, Athens, GA, 30602, USA
| | | | - Jonathan Arnold
- Genetics Department, University of Georgia, Athens, GA, 30602, USA.
| | - Leidong Mao
- School of Electrical and Computer Engineering, College of Engineering, University of Georgia, Athens, GA, 30602, USA
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2
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Arbel-Goren R, Dassa B, Zhitnitsky A, Valladares A, Herrero A, Flores E, Stavans J. Spatio-temporal coherence of circadian clocks and temporal control of differentiation in Anabaena filaments. mSystems 2024; 9:e0070023. [PMID: 38079111 PMCID: PMC10805033 DOI: 10.1128/msystems.00700-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 10/18/2023] [Indexed: 01/24/2024] Open
Abstract
Circadian clock arrays in multicellular filaments of the heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 display remarkable spatio-temporal coherence under nitrogen-replete conditions. To shed light on the interplay between circadian clocks and the formation of developmental patterns, we followed the expression of a clock-controlled gene under nitrogen deprivation, at the level of individual cells. Our experiments showed that differentiation into heterocysts took place preferentially within a limited interval of the circadian clock cycle, that gene expression in different vegetative intervals along a developed filament was discoordinated, and that the circadian clock was active in individual heterocysts. Furthermore, Anabaena mutants lacking the kaiABC genes encoding the circadian clock core components produced heterocysts but failed in diazotrophy. Therefore, genes related to some aspect of nitrogen fixation, rather than early or mid-heterocyst differentiation genes, are likely affected by the absence of the clock. A bioinformatics analysis supports the notion that RpaA may play a role as master regulator of clock outputs in Anabaena, the temporal control of differentiation by the circadian clock and the involvement of the clock in proper diazotrophic growth. Together, these results suggest that under nitrogen-deficient conditions, the clock coherent unit in Anabaena is reduced from a full filament under nitrogen-rich conditions to the vegetative cell interval between heterocysts.IMPORTANCECircadian clocks, from unicellular organisms to animals, temporally align biological processes to day and night cycles. We study the dynamics of a circadian clock-controlled gene at the individual cell level in the multicellular filamentous cyanobacterium Anabaena, under nitrogen-stress conditions. Under these conditions, some cells along filaments differentiate to carry out atmospheric nitrogen fixation and lose their capability for oxygenic photosynthesis. We found that clock synchronization is limited to organismic units of contiguous photosynthetic cells, contrary to nitrogen-replete conditions in which clocks are synchronized over a whole filament. We provided evidence that the circadian clock regulates the process of differentiation, allowing it to occur preferentially within a limited time window during the circadian clock period. Lastly, we present evidence that the signal from the core clock to clock-regulated genes is conveyed in Anabaena as in unicellular cyanobacteria.
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Affiliation(s)
- Rinat Arbel-Goren
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
| | - Bareket Dassa
- Department of Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Anna Zhitnitsky
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
| | - Ana Valladares
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Antonia Herrero
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Joel Stavans
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
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3
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Wu S, Zheng H, Wang Y, Wang L, Chen W. Cyanobacterial bioreporter of nitrate bioavailability in aquatic ecosystems. WATER RESEARCH 2023; 247:120749. [PMID: 37918203 DOI: 10.1016/j.watres.2023.120749] [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: 03/27/2023] [Revised: 10/06/2023] [Accepted: 10/16/2023] [Indexed: 11/04/2023]
Abstract
The water eutrophication, resulting from the discharge of industrial and agricultural wastewater, leads to ecological degradation. However, to date, how to assess and manage the risks of water pollution, especially nitrogen pollution, remains a particularly noteworthy issue. Nitrate, the most important nitrogen compound, has become a bottleneck restricting total nitrogen management. The development of bioreporters monitoring nitrate pollution contributes to the estimation of water quality, especially the availability of nutrients. In this study, we obtained 9 bioreporters from 40 cyanobacterial derivatives which were constructed based on different hosts, copy numbers, and sensing elements and evaluated the performance of bioreporters. The results showed that single-celled Synechocystis was more sensitive to nitrate than filamentous Anabaena, that the reporter gene luxABCDE responded faster than sfgfp in most bioreporters, and that relatively medium-copy plasmid improved the performance of sensing elements. Nine bioreporters performed well in bioavailable nitrate detection, of which AD-AS-X and AR-NI-X, activated by nitrate repletion, had the shortest response time (2 h) and the widest response range (20-800 μM), respectively. Moreover, SR-GLN-SG, activated by nitrate deficiency, exhibited the best linear response (R2 = 0.998). After parameter optimization, exponential growth phase bioreporters, culture temperature of 30 °C, sample volume of 200 μL were determined as optimal monitoring conditions. We found that common water contaminants (copper, cadmium, and phosphorus) had no impact on the performance of bioreporters, indicating the stability of bioreporters. Six out of 9 bioreporters, especially the SR-NB-X, were highly effective in detecting the bioavailable nitrate in wastewater sample. This study provides valuable references for developing more cyanobacterial bioreporters and their practical application in nitrate detection.
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Affiliation(s)
- Shanyu Wu
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Hongyan Zheng
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yuwei Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Li Wang
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Wenli Chen
- National Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
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4
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Velázquez-Suárez C, Luque I, Herrero A. The Role of MreB, MreC and MreD in the Morphology of the Diazotrophic Filament of Anabaena sp. PCC 7120. Life (Basel) 2022; 12:life12091437. [PMID: 36143472 PMCID: PMC9503725 DOI: 10.3390/life12091437] [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: 07/28/2022] [Revised: 09/07/2022] [Accepted: 09/09/2022] [Indexed: 11/27/2022] Open
Abstract
The cyanobacterium Anabaena sp. PCC 7120 forms filaments of communicating cells. Under conditions of nitrogen scarcity, some cells differentiate into heterocysts, allowing the oxygen-sensitive N2-reduction system to be expressed and operated in oxic environments. The key to diazotrophic growth is the exchange of molecules with nutritional and signaling functions between the two types of cells of the filament. During heterocyst differentiation, the peptidoglycan sacculus grows to allow cell enlargement, and the intercellular septa are rebuilt to narrow the contact surface with neighboring cells and to hold specific transport systems, including the septal junction complexes for intercellular molecular transfer, which traverse the periplasm between heterocysts and neighboring vegetative cells through peptidoglycan nanopores. Here we have followed the spatiotemporal pattern of peptidoglycan incorporation during heterocyst differentiation by Van-FL labeling and the localization and role of proteins MreB, MreC and MreD. We observed strong transitory incorporation of peptidoglycan in the periphery and septa of proheterocysts and a maintained focal activity in the center of mature septa. During differentiation, MreB, MreC and MreD localized throughout the cell periphery and at the cell poles. In mreB, mreC or mreD mutants, instances of strongly increased peripheral and septal peptidoglycan incorporation were detected, as were also heterocysts with aberrant polar morphology, even producing filament breakage, frequently lacking the septal protein SepJ. These results suggest a role of Mre proteins in the regulation of peptidoglycan growth and the formation of the heterocyst neck during differentiation, as well as in the maintenance of polar structures for intercellular communication in the mature heterocyst. Finally, as previously observed in filaments growing with combined nitrogen, in the vegetative cells of diazotrophic filaments, the lack of MreB, MreC or MreD led to altered localization of septal peptidoglycan-growth bands reproducing an altered localization of FtsZ and ZipN rings during cell division.
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The Role of Mre Factors and Cell Division in Peptidoglycan Growth in the Multicellular Cyanobacterium Anabaena. mBio 2022; 13:e0116522. [PMID: 35876506 PMCID: PMC9426583 DOI: 10.1128/mbio.01165-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Bacteria in general serve two main tasks: cell growth and division. Both processes include peptidoglycan extension to allow cell expansion and to form the poles of the daughter cells, respectively. The cyanobacterium Anabaena forms filaments of communicated cells in which the outer membrane and the peptidoglycan sacculus, which is engrossed in the intercellular regions between contiguous cells, are continuous along the filament. During the growth of Anabaena, peptidoglycan incorporation was weak at the cell periphery. During cell division, midcell peptidoglycan incorporation matched the localization of the divisome, and incorporation persisted in the intercellular septa, even after the division was completed. MreB, MreC, and MreD were located throughout the cell periphery and, in contrast to other bacteria, also to the divisome all along midcell peptidoglycan growth. In Anabaena mutants bearing inactivated mreB, mreC, or mreD genes, which showed conspicuous alterations in the filament morphology, consecutive septal bands of peptidoglycan growth were frequently not parallel to each other and were irregularly spaced along the filament, reproducing the disposition of the Z-ring. Both lateral and septal growth was impaired in strains down-expressing Z-ring components, and MreB and MreD appeared to directly interact with some divisome components. We propose that, in Anabaena, association with the divisome is a way for localization of MreB, MreC, and MreD at the cell poles, where they regulate lateral, midcell, and septal peptidoglycan growth with the latter being involved in localization and maintenance of the intercellular septal-junction protein structures that mediate cell-cell communication along the filament.
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6
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Abstract
Heterocyst differentiation that occurs in some filamentous cyanobacteria, such as Anabaena sp. PCC 7120, provides a unique model for prokaryotic developmental biology. Heterocyst cells are formed in response to combined-nitrogen deprivation and possess a microoxic environment suitable for nitrogen fixation following extensive morphological and physiological reorganization. A filament of Anabaena is a true multicellular organism, as nitrogen and carbon sources are exchanged among different cells and cell types through septal junctions to ensure filament growth. Because heterocysts are terminally differentiated cells and unable to divide, their activity is an altruistic behavior dedicated to providing fixed nitrogen for neighboring vegetative cells. Heterocyst development is also a process of one-dimensional pattern formation, as heterocysts are semiregularly intercalated among vegetative cells. Morphogens form gradients along the filament and interact with each other in a fashion that fits well into the Turing model, a mathematical framework to explain biological pattern formation. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Xiaoli Zeng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China; ,
| | - Cheng-Cai Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, China; , .,Institut WUT-AMU, Aix-Marseille Université and Wuhan University of Technology, Wuhan, Hubei, China.,Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China
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7
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Khan E, Saghafi S, Diekman CO, Rotstein HG. The emergence of polyglot entrainment responses to periodic inputs in vicinities of Hopf bifurcations in slow-fast systems. CHAOS (WOODBURY, N.Y.) 2022; 32:063137. [PMID: 35778129 DOI: 10.1063/5.0079198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 04/04/2022] [Indexed: 06/15/2023]
Abstract
Several distinct entrainment patterns can occur in the FitzHugh-Nagumo (FHN) model under external periodic forcing. Investigating the FHN model under different types of periodic forcing reveals the existence of multiple disconnected 1:1 entrainment segments for constant, low enough values of the input amplitude when the unforced system is in the vicinity of a Hopf bifurcation. This entrainment structure is termed polyglot to distinguish it from the single 1:1 entrainment region (monoglot) structure typically observed in Arnold tongue diagrams. The emergence of polyglot entrainment is then explained using phase-plane analysis and other dynamical system tools. Entrainment results are investigated for other slow-fast systems of neuronal, circadian, and glycolytic oscillations. Exploring these models, we found that polyglot entrainment structure (multiple 1:1 regions) is observed when the unforced system is in the vicinity of a Hopf bifurcation and the Hopf point is located near a knee of a cubic-like nullcline.
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Affiliation(s)
- Emel Khan
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
| | - Soheil Saghafi
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
| | - Horacio G Rotstein
- Federated Department of Biological Sciences, New Jersey Institute of Technology & Rutgers University, Newark, New Jersey 07102, USA
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8
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Jabbur ML, Johnson CH. Spectres of Clock Evolution: Past, Present, and Yet to Come. Front Physiol 2022; 12:815847. [PMID: 35222066 PMCID: PMC8874327 DOI: 10.3389/fphys.2021.815847] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/22/2021] [Indexed: 01/20/2023] Open
Abstract
Circadian clocks are phylogenetically widespread biological oscillators that allow organisms to entrain to environmental cycles and use their steady-state phase relationship to anticipate predictable daily phenomena – such as the light-dark transitions of a day – and prepare accordingly. Present from cyanobacteria to mammals, circadian clocks are evolutionarily ancient and are thought to increase the fitness of the organisms that possess them by allowing for better resource usage and/or proper internal temporal order. Here, we review literature with respect to the ecology and evolution of circadian clocks, with a special focus on cyanobacteria as model organisms. We first discuss what can be inferred about future clock evolution in response to climate change, based on data from latitudinal clines and domestication. We then address our current understanding of the role that circadian clocks might be contributing to the adaptive fitness of cyanobacteria at the present time. Lastly, we discuss what is currently known about the oldest known circadian clock, and the early Earth conditions that could have led to its evolution.
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9
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Cable J, Elowitz MB, Domingos AI, Habib N, Itzkovitz S, Hamidzada H, Balzer MS, Yanai I, Liberali P, Whited J, Streets A, Cai L, Stergachis AB, Hong CKY, Keren L, Guilliams M, Alon U, Shalek AK, Hamel R, Pfau SJ, Raj A, Quake SR, Zhang NR, Fan J, Trapnell C, Wang B, Greenwald NF, Vento-Tormo R, Santos SDM, Spencer SL, Garcia HG, Arekatla G, Gaiti F, Arbel-Goren R, Rulands S, Junker JP, Klein AM, Morris SA, Murray JI, Galloway KE, Ratz M, Romeike M. Single cell biology-a Keystone Symposia report. Ann N Y Acad Sci 2021; 1506:74-97. [PMID: 34605044 DOI: 10.1111/nyas.14692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/27/2022]
Abstract
Single cell biology has the potential to elucidate many critical biological processes and diseases, from development and regeneration to cancer. Single cell analyses are uncovering the molecular diversity of cells, revealing a clearer picture of the variation among and between different cell types. New techniques are beginning to unravel how differences in cell state-transcriptional, epigenetic, and other characteristics-can lead to different cell fates among genetically identical cells, which underlies complex processes such as embryonic development, drug resistance, response to injury, and cellular reprogramming. Single cell technologies also pose significant challenges relating to processing and analyzing vast amounts of data collected. To realize the potential of single cell technologies, new computational approaches are needed. On March 17-19, 2021, experts in single cell biology met virtually for the Keystone eSymposium "Single Cell Biology" to discuss advances both in single cell applications and technologies.
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Affiliation(s)
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California.,Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California
| | - Ana I Domingos
- Department of Physiology, Anatomy & Genetics, Oxford University, Oxford, United Kingdom.,The Howard Hughes Medical Institute, New York, New York
| | - Naomi Habib
- Cell Circuits Program, Broad Institute, Cambridge, Massachusetts.,Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Shalev Itzkovitz
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Homaira Hamidzada
- Toronto General Hospital Research Institute, University Health Network; Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research and Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Michael S Balzer
- Renal, Electrolyte, and Hypertension Division, Department of Medicine and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Itai Yanai
- Institute for Computational Medicine, NYU Langone Health, New York, New York
| | - Prisca Liberali
- Friedrich Miescher Institute for Biomedical Research (FMI), Basel, Switzerland
| | - Jessica Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts
| | - Aaron Streets
- Department of Bioengineering and Center for Computational Biology, University of California, Berkeley, Berkeley, California.,Chan Zuckerberg Biohub, San Francisco, California
| | - Long Cai
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California
| | - Andrew B Stergachis
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington; and Brotman Baty Institute for Precision Medicine, Seattle, Washington
| | - Clarice Kit Yee Hong
- Edison Center for Genome Sciences and Systems Biology, Washington University in St. Louis, St. Louis, Missouri.,Department of Genetics, Washington University in St. Louis, St. Louis, Missouri
| | - Leeat Keren
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel.,Department of Pathology, School of Medicine, Stanford University, Stanford, California
| | - Martin Guilliams
- Laboratory of Myeloid Cell Biology in Tissue Homeostasis and Regeneration, VIB-UGent Center for Inflammation Research, and Unit of Immunoregulation and Mucosal Immunology, VIB Inflammation Research Center, and Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Uri Alon
- Faculty of Sciences, Department of Human Biology, University of Haifa, Haifa, Israel
| | - Alex K Shalek
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
| | - Regan Hamel
- Department of Clinical Neurosciences and NIHR Biomedical Research Centre, University of Cambridge, Cambridge, United Kingdom
| | - Sarah J Pfau
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts
| | - Arjun Raj
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Stephen R Quake
- Chan Zuckerberg Biohub, San Francisco, California.,Department of Bioengineering, Stanford University, Stanford, California.,Department of Applied Physics, Stanford University, Stanford, California
| | - Nancy R Zhang
- Graduate Group in Genomics and Computational Biology and Department of Statistics, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jean Fan
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Cole Trapnell
- Department of Genome Sciences, University of Washington School of Medicine; Brotman Baty Institute for Precision Medicine; and Allen Discovery Center for Cell Lineage Tracing, Seattle, Washington
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, California.,Department of Developmental Biology, Stanford University School of Medicine, Stanford, California
| | - Noah F Greenwald
- Department of Pathology, School of Medicine, Stanford University, Stanford, California
| | | | | | - Sabrina L Spencer
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado
| | - Hernan G Garcia
- Department of Physics; Biophysics Graduate Group; Department of Molecular and Cell Biology; and Institute for Quantitative Biosciences-QB3, University of California at Berkeley, Berkeley, California
| | | | - Federico Gaiti
- New York Genome Center and Meyer Cancer Center, Weill Cornell Medicine, New York, New York
| | - Rinat Arbel-Goren
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot, Israel
| | - Steffen Rulands
- Max Planck Institute for the Physics of Complex Systems, and Center for Systems Biology Dresden, Dresden, Germany
| | - Jan Philipp Junker
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Allon M Klein
- Department of Systems Biology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts
| | - Samantha A Morris
- Department of Genetics, Washington University in St. Louis, St. Louis, Missouri.,Department of Developmental Biology and Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - John I Murray
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kate E Galloway
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Michael Ratz
- Department of Cell and Molecular Biology, Karolinska Institute, Solna, Sweden
| | - Merrit Romeike
- Max Perutz Laboratories Vienna, University of Vienna, Vienna, Austria
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10
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Abstract
Circadian clocks are important to much of life on Earth and are of inherent interest to humanity, implicated in fields ranging from agriculture and ecology to developmental biology and medicine. New techniques show that it is not simply the presence of clocks, but coordination between them that is critical for complex physiological processes across the kingdoms of life. Recent years have also seen impressive advances in synthetic biology to the point where parallels can be drawn between synthetic biological and circadian oscillators. This review will emphasize theoretical and experimental studies that have revealed a fascinating dichotomy of coupling and heterogeneity among circadian clocks. We will also consolidate the fields of chronobiology and synthetic biology, discussing key design principles of their respective oscillators.
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Affiliation(s)
- Chris N Micklem
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK.,The Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CH3 0HE, UK
| | - James C W Locke
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, UK
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11
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Single-Cell Measurements of Fixation and Intercellular Exchange of C and N in the Filaments of the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120. mBio 2021; 12:e0131421. [PMID: 34399619 PMCID: PMC8406292 DOI: 10.1128/mbio.01314-21] [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] [Indexed: 11/29/2022] Open
Abstract
Under diazotrophic conditions, the model filamentous, heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 develops a metabolic strategy based on the physical separation of the processes of oxygenic photosynthesis, in vegetative cells, and N2 fixation, in heterocysts. This strategy requires the exchange of carbon and nitrogen metabolites and their distribution along the filaments, which takes place through molecular diffusion via septal junctions involving FraCD proteins. Here, Anabaena was incubated in a time course (up to 20 h) with [13C]bicarbonate and 15N2 and analyzed by secondary ion mass spectrometry imaging (SIMS) (large-geometry SIMS [LG-SIMS] and NanoSIMS) to quantify C and N assimilation and distribution in the filaments. The 13C/12C and 15N/14N ratios measured in wild-type filaments showed a general increase with time. The enrichment was relatively homogeneous in vegetative cells along individual filaments, while it was reduced in heterocysts. Heterocysts, however, accumulated recently fixed N at their poles, in which the cyanophycin plug [multi-l-arginyl-poly(l-aspartic acid)] is located. In contrast to the rather homogeneous label found along stretches of vegetative cells, 13C/12C and 15N/14N ratios were significantly different between filaments both at the same and different time points, showing high variability in metabolic states. A fraC fraD mutant did not fix N2, and the 13C/12C ratio was homogeneous along the filament, including the heterocyst in contrast to the wild type. Our results show the consumption of reduced C in the heterocysts associated with the fixation and export of fixed N and present an unpredicted heterogeneity of cellular metabolic activity in different filaments of an Anabaena culture under controlled conditions.
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