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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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Joublin-Delavat A, Touahri K, Crétin P, Morot A, Rodrigues S, Jesus B, Trigodet F, Delavat F. Genetic and physiological insights into the diazotrophic activity of a non-cyanobacterial marine diazotroph. Environ Microbiol 2022; 24:6510-6523. [PMID: 36302093 PMCID: PMC10099842 DOI: 10.1111/1462-2920.16261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 10/21/2022] [Indexed: 01/12/2023]
Abstract
Nitrogen (N2 ) fixation, or diazotrophy, supports a large part of primary production in oceans. Culture-independent approaches highlighted the presence in abundance of marine non-cyanobacterial diazotrophs (NCD), but their ecophysiology remains elusive, mostly because of the low number of isolated NCD and because of the lack of available genetic tools for these isolates. Here, a dual genetic and functional approach allowed unveiling the ecophysiology of a marine NCD affiliated to the species Vibrio diazotrophicus. Physiological characterization of the first marine NCD mutant obtained so far was performed using a soft-gellan assay, demonstrating that a ΔnifH mutant is not able to grow in nitrogen-free media. Furthermore, we demonstrated that V. diazotrophicus produces a thick biofilm under diazotrophic conditions, suggesting biofilm production as an adaptive response of this NCD to cope with the inhibition of nitrogen fixation by molecular oxygen. Finally, the genomic signature of V. diazotrophicus is essentially absent from metagenomic data of Tara Ocean expeditions, despite having been isolated from various marine environments. We think that the genetically tractable V. diazotrophicus strain used in this study may serve as an ideal model to study the ecophysiology of these overlooked procaryotic group.
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Affiliation(s)
| | - Katia Touahri
- Nantes Université, CNRS, US2B, UMR6286, Nantes, France.,Laboratoire Chimie et Biochimie de Molécules Bioactives, Université de Strasbourg/CNRS, UMR7177, Strasbourg, France
| | | | - Amandine Morot
- Univ Brest, CNRS, IRD, Ifremer, LEMAR, Plouzané, France.,Université de Bretagne-Sud, UR3884, LBCM, IUEM, Lorient, France
| | | | - Bruno Jesus
- Nantes Université, RSBE2 ISOMer, UR2160, Nantes, France
| | - Florian Trigodet
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
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Dong Y, Aharoni A. Image to insight: exploring natural products through mass spectrometry imaging. Nat Prod Rep 2022; 39:1510-1530. [PMID: 35735199 DOI: 10.1039/d2np00011c] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: 2017 to 2022Mass spectrometry imaging (MSI) has become a mature molecular imaging technique that is well-matched for natural product (NP) discovery. Here we present a brief overview of MSI, followed by a thorough discussion of different MSI applications in NP research. This review will mainly focus on the recent progress of MSI in plants and microorganisms as they are the main producers of NPs. Specifically, the opportunity and potential of combining MSI with other imaging modalities and stable isotope labeling are discussed. Throughout, we focus on both the strengths and weaknesses of MSI, with an eye on future improvements that are necessary for the progression of MSI toward routine NP studies. Finally, we discuss new areas of research, future perspectives, and the overall direction that the field may take in the years to come.
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Affiliation(s)
- Yonghui Dong
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Asaph Aharoni
- Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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