Nutrient scavenging and energy management: acclimation responses in nitrogen and sulfur deprived Chlamydomonas

Saroussi, Shai; Sanz-Luque, Emanuel; Kim, Rick G.; Grossman, Arthur R.

doi:10.1016/j.pbi.2017.06.002

Cited by 48 publications

(50 citation statements)

References 57 publications

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“…In summary, characterization of the sulfur limitation-induced expression of THB1 expands our understanding of the regulatory aspects of network during S deprivation beyond previous finding of the core components of S-specific responses (Saroussi et al, 2017). In this study, we find that NR-NOFNiR system plays a positive role in THB1 upregulation by generation of NO in S-starved cells (Fig.…”

Section: Discussionsupporting

confidence: 62%

“…In S-replete medium, the action of SNRK2.1 is negatively controlled by another kinase, SNRK2.2. Furthermore, SNRK2.2 is repressed by protein SAC1 (Saroussi et al, 2017). We hypothesized that THB1 expression is not controlled by signaling proteins and regulators associated with S deprivation specific responses.…”

Section: Discussionmentioning

confidence: 99%

“…When experiencing S deprivation, Chlamydomonas cells increase the capacity for scavenging S from both internal and external resources (Aksoy et al, 2013;Davies et al, 1994). S-deprived Chlamydomonas exhibits upregulation of numerous proteins associated with sulfate uptake and assimilation, changes in metabolism and inter-Zhanneta Zalutskaya, Valentina Filina and Elena Ermilova nal S recycling (Saroussi et al, 2017;Zhang et al, 2004). Moreover, a truncated hemoglobin 1 is essential for proper cell response to S limitation (Minaeva et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Sulfur deprivation-induced expression of THB1, a Chlamydomonas reinhardtii truncated hemoglobin, is mediated by nitrate reductase-dependent NO production

2018

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SummaryDuring sulfur (S) deprivation, Chlamydomonas reinhardtii mediates a suite of specific responses to efficiently acquire S from various sources and remodel primary metabolism. Although the truncated hemoglobin 1 (THB1)-dependent regulation of a subset of S limitation-responsive genes has been elucidated, the mechanism through which THB1 transcription is triggered in S-deprived cells is not known. Here, we show that signaling proteins and regulators associated with S deprivation specific responses did not control THB1 expression. Following S depletion, rapid increase in nitrite concentrations is essential for THB1 upregulation. These changes are consistent with NO accumulation. Increased nitrite, NO and THB1 mRNA levels were not observed in mutant cells without diaphorase-NR activity. Our findings suggest that nitrate reductase -nitric oxide-forming nitrite reductase system plays a positive role in THB1 transcription via generation of NO from nitrite in S-starved cells. NR-dependent NO production may be regarded as an early trigger, which contributes to Chlamydomonas adaptability to nutrient stresses.

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Section: Discussionsupporting

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sulfur deprivation-induced expression of THB1, a Chlamydomonas reinhardtii truncated hemoglobin, is mediated by nitrate reductase-dependent NO production

2018

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“…Photosynthetic organisms convert absorbed light energy into chemical energy in the process of photosynthesis, which requires membrane-associated, light-dependent reaction centers, electron transport components, and ATP synthase; these components drive both ATP and NADPH formation, which in turn are required for the fixation of CO 2 by the stromal localized Calvin-Benson-Bassham cycle (CBBC) 3 (1). In the natural environment, photosynthetic organisms experience changes in light intensity and quality, temperature, nutrient levels, water availability and quality, and a variety of other factors.…”

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confidence: 99%

The mitochondrial alternative oxidase from Chlamydomonas reinhardtii enables survival in high light

Kaye¹,

Huang²,

Clowez

et al. 2019

Journal of Biological Chemistry

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Edited by Ursula JakobPhotosynthetic organisms often experience extreme light conditions that can cause hyper-reduction of the chloroplast electron transport chain, resulting in oxidative damage. Accumulating evidence suggests that mitochondrial respiration and chloroplast photosynthesis are coupled when cells are absorbing high levels of excitation energy. This coupling helps protect the cells from hyper-reduction of photosynthetic electron carriers and diminishes the production of reactive oxygen species (ROS). To examine this cooperative protection, here we characterized Chlamydomonas reinhardtii mutants lacking the mitochondrial alternative terminal respiratory oxidases, CrAOX1 and CrAOX2. Using fluorescent fusion proteins, we experimentally demonstrated that both enzymes localize to mitochondria. We also observed that the mutant strains were more sensitive than WT cells to high light under mixotrophic and photoautotrophic conditions, with the aox1 strain being more sensitive than aox2. Additionally, the lack of CrAOX1 increased ROS accumulation, especially in very high light, and damaged the photosynthetic machinery, ultimately resulting in cell death. These findings indicate that the Chlamydomonas AOX proteins can participate in acclimation of C. reinhardtii cells to excess absorbed light energy. They suggest that when photosynthetic electron carriers are highly reduced, a chloroplast-mitochondria coupling allows safe dissipation of photosynthetically derived electrons via the reduction of O 2 through AOX (especially AOX1)-dependent mitochondrial respiration.

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“…N deprivation and S deprivation methods have significant similarities, but the aerobic phase with N‐deprivation strategy is significantly longer, leading to delayed hydrogen production . The accumulation of starch and lipids is more effective with N deprivation than with S deprivation, and the accumulation of ammonium salts was observed, indicating that degradation of the protein occurs .…”

Section: Metabolism Regulation and Hydrogen Production In Microalgaementioning

confidence: 99%

Microalgal Hydrogen Production

et al. 2020

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Microalgae, as facultative aerobic organisms, convert solar energy to produce biohydrogen under anaerobic condition. Biohydrogen is a kind of ideal clean and renewable energy source with great commercial potential. Many endeavors have been focused on improving the biohydrogen yields by various means. Here, the research history of hydrogen production by microalgae (including cyanobacteria and green algae), the characteristics of nitrogenase and hydrogenase, the mechanisms of hydrogen production, the technological progress, and the application of enzymatic, genetic, and metabolic engineering methods to improve hydrogen production by microalgae are reviewed. In addition, the regulation of anaerobic metabolisms of Chlamydomonas reinhardtii after the disruption of key enzymes functioning in the fermentative pathways is discussed. Finally, the main challenges and obstacles facing the more efficient production and commercialization of hydrogen production from microalgae in the future are proposed.

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Nutrient scavenging and energy management: acclimation responses in nitrogen and sulfur deprived Chlamydomonas

Cited by 48 publications

References 57 publications

Sulfur deprivation-induced expression of THB1, a Chlamydomonas reinhardtii truncated hemoglobin, is mediated by nitrate reductase-dependent NO production

Sulfur deprivation-induced expression of THB1, a Chlamydomonas reinhardtii truncated hemoglobin, is mediated by nitrate reductase-dependent NO production

The mitochondrial alternative oxidase from Chlamydomonas reinhardtii enables survival in high light

Microalgal Hydrogen Production

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