Molecular circuit of heterocyst differentiation in cyanobacteria

Harish,; Seth, Kunal

doi:10.1002/jobm.202000266

Cited by 14 publications

(11 citation statements)

References 53 publications

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“…PCC 7120, the concentration of 2‐OG increases to promote heterocyst differentiation (Li, Laurent, Konde, Bé du, & Zhang, 2003), upon N deprivation. However, heterocyst differentiation happens within the first 6–8 hr of N deprivation, by the generation of proto‐heterocysts that turn into functional heterocysts within 24 hr (Harish & Seth, 2020; A. M. Muro‐Pastor & Hess, 2012). It is thus reasonable to expect that the increase in the concentration of 2‐OG which triggers heterocyst differentiation occurs mainly within the first few hours upon nitrogen deprivation.…”

Section: Discussionmentioning

confidence: 99%

“…PCC 7120, the concentration of 2-OG increases to promote heterocyst differentiation (Li, Laurent, Konde, Bé du, & Zhang, 2003), upon N deprivation. However, heterocyst differentiation happens within the first 6-8 hr of N deprivation, by the generation of proto-heterocysts that turn into functional heterocysts within 24 hr (Harish & Seth, 2020;A. M. Muro-Pastor & Hess, 2012).…”

Section: Lack Of Amt Transporters Induces Metabolic Adaptation Spanning Both C and N Metabolism With A Potential Impact On The Metabolitementioning

confidence: 99%

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Calm on the surface, dynamic on the inside. Molecular homeostasis of Anabaena sp. PCC 7120 nitrogen metabolism

Perin

Fletcher

Sagi‐Kiss

et al. 2021

Plant Cell & Environment

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Nitrogen sources are all converted into ammonium/ia as a first step of assimilation. It is reasonable to expect that molecular components involved in the transport of ammonium/ ia across biological membranes connect with the regulation of both nitrogen and central metabolism. We applied both genetic (i.e., Δamt mutation) and environmental treatments to a target biological system, the cyanobacterium Anabaena sp PCC 7120. The aim was to both perturb nitrogen metabolism and induce multiple inner nitrogen states, respectively, followed by targeted quantification of key proteins, metabolites and enzyme activities. The absence of AMT transporters triggered a substantial whole-system response, affecting enzyme activities and quantity of proteins and metabolites, spanning nitrogen and carbon metabolisms. Moreover, the Δamt strain displayed a molecular fingerprint indicating nitrogen deficiency even under nitrogen replete conditions. Contrasting with such dynamic adaptations was the striking near-complete lack of an externally measurable altered phenotype. We conclude that this species evolved a highly robust and adaptable molecular network to maintain homeostasis, resulting in substantial internal but minimal external perturbations. This analysis provides evidence for a potential role of AMT transporters in the regulatory/signalling network of nitrogen metabolism and the existence of a novel fourth regulatory mechanism controlling glutamine synthetase activity.

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Section: Discussionmentioning

confidence: 99%

Section: Lack Of Amt Transporters Induces Metabolic Adaptation Spanning Both C and N Metabolism With A Potential Impact On The Metabolitementioning

confidence: 99%

Calm on the surface, dynamic on the inside. Molecular homeostasis of Anabaena sp. PCC 7120 nitrogen metabolism

Perin

Fletcher

Sagi‐Kiss

et al. 2021

Plant Cell & Environment

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“…In filamentous diazotrophic cyanobacteria species, such as Anabaena sp., the fixation of dinitrogen is catalyzed by the enzyme nitrogenase within terminally differentiated heterocysts, providing fixed nitrogen to vegetative cells and in turn receiving fixed carbon produced from their oxygenic photosynthesis (Burnat et al, 2014;Herrero et al, 2016;Harish, 2020). Hence, the coordination of carbon and nitrogen metabolism and intracellular nutrient balance is fundamental to cyanobacteria for maintaining productivity and acclimating to perceived stress in changing environments (Schwarz and Forchhammer, 2005;Jiang et al, 2018;Zhang et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Nano-Titanium Dioxide Exposure Impacts Nitrogen Metabolism Pathways in Cyanobacteria

Cherchi

Lin

2021

Environmental Engineering Science

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The wide and increasing use of nano-titanium dioxide (nTiO 2 ) has led to its release in the environment that will likely impact aquatic eco-relevant biota. In this study, we investigated the impact of sublethal concentrations of nTiO 2 on the nitrogen (N) metabolism of the primary producer, nitrogen-fixing cyanobacteria Anabaena PCC 7120, using transcriptional-level information of biomarker genes involved in global N regulation, N fixation-, N assimilation-, and N storage-specific pathways. The results showed that both the circadian patterns of cyanobacterial metabolism and nTiO 2 intrinsic properties distinctively governed the toxicity responses during light and dark exposure to nTiO 2 . During illuminated conditions, the majority of genes linked to cellular nitrogen status exhibited a clear upregulation in the dose range of 6-60 mg/L$h, whereas overall gene downregulation was mainly observed at the end of dark cycle, characterized by low cell metabolism and energy (ATP) levels. The nTiO 2 dose-dependent production of intracellular metabolites (amino acids) involved in both the GS-GOGAT pathway of N assimilation and the intracellular N storage pathway suggests that pathways involving amino acid biosynthesis or degradation might be activated or repressed. This, possibly, contributes to the increase of newly synthesized proteins needed for detoxification in response to the cellular stresses induced by nTiO 2 treatment. These findings suggest that under environmental perturbations generated by nTiO 2 , cyanobacteria are likely to modify their intracellular carbon and nitrogen balance, thus impact, at a larger scale, ecological trophic interactions and food web dynamics within complex ecological systems.

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“…Unicellular cyanobacteria (Chrocosphera, Gloeothece and Cyanothece) temporally separate photosynthesis (production of O 2 ) during the day from N 2 fixation during the night (when O 2 is no longer produced by photosynthesis and is consumed by respiration). Many diazotrophic pluricellular (filamentous) cyanobacteria, such as Nostoc (Anabaena) sp., respond to nitrogen depletion by differentiating (irreversibly) some of their vegetative cells into heterocysts, the non-diving, photosynthetically inactive, cells that fix atmospheric (inorganic) nitrogen (N 2 ) (Harish & Kunal, 2020;Herrero et al, 2013). This differentiation process results in a heterocyst pattern consisting of two heterocysts separated by about 10 to 15 vegetative cells (Herrero, Stavans, & Flores, 2016).…”

mentioning

confidence: 99%

“…A few other regulators of gene expression participate at specific differentiation steps, and a specific transcription factor, CnfR, activates nif genes expression under the micro-oxic conditions of the heterocyst (Flores, Picossi, Valladares, & Herrero, 2019). Recently, the role of small RNA and interruption DNA elements that influence the heterocyst formation and function has also been identified (Harish & Kunal, 2020).…”

mentioning

confidence: 99%

Genomics of cyanobacteria: New insights and lessons for shaping our future—A follow-up of volume 65: Genomics of cyanobacteria

Chauvat

Cassier‐Chauvat

2021

Advances in Botanical Research

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Cyanobacteria, the only known photosynthetic prokaryotes, are ancient organisms regarded as the producers of the Earth's oxygenic atmosphere and the ancestors of plant chloroplasts. Contemporary cyanobacteria have evolved as widely-diverse organisms in colonizing most aquatic and soil biotopes, where they face various environmental challenges and competition or symbiosis with other organisms. Cyanobacteria exhibit a wide morphological diversity (unicellular/multicellular, cylindrical/spherical shapes) and many species differentiate specialized cells for growth and survival under adverse conditions. They convert captured solar energy at high efficiencies, to fix an enormous amount of carbon from CO 2 into a huge biomass that sustains a large part of the food chain, and they tolerate high CO 2 content in gas streams. They also synthesize a vast array of biologically active metabolites with great interests for human health and industries. Hence, they are viewed as promising "low-cost" cell factories for the carbon-neutral production of chemicals, thanks to their simple nutritional requirements, their metabolic robustness and plasticity, and the powerful genetics of some model strains.In 2013 when ABR vol 65 entitled "Genomics of Cyanobacteria" was published, approximately 70 cyanobacteria had their genomes fully or partially sequenced. Since then, the number has increased up to about 2000 (https:// genome.jgi.doe.gov/portal/), genome editing studies using CRISPR/Cas have been reported in several model cyanobacteria (Gale et al., 2019; ☆

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Molecular circuit of heterocyst differentiation in cyanobacteria

Cited by 14 publications

References 53 publications

Calm on the surface, dynamic on the inside. Molecular homeostasis of Anabaena sp. PCC 7120 nitrogen metabolism

Calm on the surface, dynamic on the inside. Molecular homeostasis of Anabaena sp. PCC 7120 nitrogen metabolism

Nano-Titanium Dioxide Exposure Impacts Nitrogen Metabolism Pathways in Cyanobacteria

Genomics of cyanobacteria: New insights and lessons for shaping our future—A follow-up of volume 65: Genomics of cyanobacteria

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