Nitrogen metabolism in Chlamydomonas

Calatrava, Victoria; Tejada‐Jiménez, Manuel; Sanz-Luque, Emanuel; Fernández, Emilio; Galván, Aurora

doi:10.1016/b978-0-12-821430-5.00004-3

Cited by 10 publications

(8 citation statements)

References 282 publications

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“…Malate dehydrogenases are located in the chloroplast, in peroxisome (also named glyoxysomes in C. reinhardtii [152]), in the cytoplasm and in the mitochondria. Various other transporters also contribute to the maintenance of the metabolic flux, such inorganic phosphate, ammonium and nitrate/nitrite transporters [153]. Bicarbonate transporters have been discussed above in Pyrenoid and carboxysome section.…”

Section: Exchange Of Metabolites Across the Boundaries Of Organellesmentioning

confidence: 99%

Location of the photosynthetic carbon metabolism in microcompartments and separated phases in microalgal cells

Launay,

Avilan,

Gérard

et al. 2023

FEBS Letters

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Carbon acquisition, assimilation and storage in eukaryotic microalgae and cyanobacteria occur in multiple compartments that have been characterised by the location of the enzymes involved in these functions. These compartments can be delimited by bilayer membranes, such as the chloroplast, the lumen, the peroxisome, the mitochondria or monolayer membranes, such as lipid droplets or plastoglobules. They can also originate from liquid–liquid phase separation such as the pyrenoid. Multiple exchanges exist between the intracellular microcompartments, and these are reviewed for the CO2 concentration mechanism, the Calvin–Benson–Bassham cycle, the lipid metabolism and the cellular energetic balance. Progress in microscopy and spectroscopic methods opens new perspectives to characterise the molecular consequences of the location of the proteins involved, including intrinsically disordered proteins.

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Section: Exchange Of Metabolites Across the Boundaries Of Organellesmentioning

confidence: 99%

Location of the photosynthetic carbon metabolism in microcompartments and separated phases in microalgal cells

Launay,

Avilan,

Gérard

et al. 2023

FEBS Letters

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“…Carbon (C) and nitrogen (N) are the most abundant elements in cells, and their assimilation and distribution are tightly regulated to maximize growth. Plants and algae acquire N mostly through the assimilation of nitrate, nitrite or ammonium (Liu et al, 2022;Calatrava et al, 2023). Ammonium, the product of most N assimilation pathways, is ultimately transferred to L-glutamate (Glu) by glutamine synthetase (GS), forming L-glutamine (Gln).…”

Section: Introductionmentioning

confidence: 99%

The activation ofChlamydomonas reinhardtiialpha amylase 2 by glutamine requires its N-terminal ACT domain

Scholtysek,

Poetsch,

Hofmann

et al. 2024

Preprint

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The coordination of assimilation pathways for all the elements that make up cellular components is a vital task for every organism. Integrating the assimilation and use of carbon (C) and nitrogen (N) is of particular importance because of the high cellular abundance of these elements. Starch is one of the most important storage polymers of photosynthetic organisms, and a complex regulatory network ensures that biosynthesis and degradation of starch are coordinated with photosynthetic activity and growth. Here, we analyzed three starch metabolism enzymes of Chlamydomonas reinhardtii that we captured by a cyclic guanosine monophosphate- (cGMP-) affinity chromatography approach, namely soluble starch synthase STA3, starch branching enzyme SBE1 and lower case Greek alpha-amylase AMA2. While none of the recombinant enzymes was directly affected by the presence of cGMP or other nucleotides, suggesting an indirect binding to cGMP, AMA2 activity was stimulated in the presence of L-glutamine (Gln). This activating effect required the enzyme's N-terminal aspartate kinase-chorismate mutase-tyrA (ACT) domain. Gln is the first N assimilation product and not only a central compound for the biosynthesis of N-containing molecules, but also a recognized signaling molecule for the N status. Our observation suggests that AMA2 might be a means to coordinate N- and C metabolism at the enzymatic level, increasing the liberation of C-skeletons from starch when high Gln levels signal an abundance of assimilated N.

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“…Nitrogen (N) is one of most essential nutrients for plant growth and development and is involved in the biosynthesis of proteins, nucleic acids, chlorophyll, and several hormones [1][2][3]. Therefore, appropriate N fertilizer use is critical in increasing crop yield and improving the quality of agricultural products.…”

Section: Introductionmentioning

confidence: 99%

Bicarbonate-Dependent Detoxification by Mitigating Ammonium-Induced Hypoxic Stress in Triticum aestivum Root

Liu,

Zhang,

Tang

et al. 2024

Biology

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Ammonium (NH4+) toxicity is ubiquitous in plants. To investigate the underlying mechanisms of this toxicity and bicarbonate (HCO3−)-dependent alleviation, wheat plants were hydroponically cultivated in half-strength Hoagland nutrient solution containing 7.5 mM NO3− (CK), 7.5 mM NH4+ (SA), or 7.5 mM NH4+ + 3 mM HCO3− (AC). Transcriptomic analysis revealed that compared to CK, SA treatment at 48 h significantly upregulated the expression of genes encoding fermentation enzymes (pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH), and lactate dehydrogenase (LDH)) and oxygen consumption enzymes (respiratory burst oxidase homologs, dioxygenases, and alternative oxidases), downregulated the expression of genes encoding oxygen transporters (PIP-type aquaporins, non-symbiotic hemoglobins), and those involved in energy metabolism, including tricarboxylic acid (TCA) cycle enzymes and ATP synthases, but upregulated the glycolytic enzymes in the roots and downregulated the expression of genes involved in the cell cycle and elongation. The physiological assay showed that SA treatment significantly increased PDC, ADH, and LDH activity by 36.69%, 43.66%, and 61.60%, respectively; root ethanol concentration by 62.95%; and lactate efflux by 23.20%, and significantly decreased the concentrations of pyruvate and most TCA cycle intermediates, the complex V activity, ATP content, and ATP/ADP ratio. As a consequence, SA significantly inhibited root growth. AC treatment reversed the changes caused by SA and alleviated the inhibition of root growth. In conclusion, NH4+ treatment alone may cause hypoxic stress in the roots, inhibit energy generation, suppress cell division and elongation, and ultimately inhibit root growth, and adding HCO3− remarkably alleviates the NH4+-induced inhibitory effects on root growth largely by attenuating the hypoxic stress.

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Nitrogen metabolism in Chlamydomonas

Cited by 10 publications

References 282 publications

Location of the photosynthetic carbon metabolism in microcompartments and separated phases in microalgal cells

Location of the photosynthetic carbon metabolism in microcompartments and separated phases in microalgal cells

The activation ofChlamydomonas reinhardtiialpha amylase 2 by glutamine requires its N-terminal ACT domain

Bicarbonate-Dependent Detoxification by Mitigating Ammonium-Induced Hypoxic Stress in Triticum aestivum Root

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