System Response of Metabolic Networks in Chlamydomonas reinhardtii to Total Available Ammonium

Lee, Mi Kyung; Park, Jeong Jin; Barupal, Dinesh Kumar; Fiehn, Oliver

doi:10.1074/mcp.m111.016733

Cited by 94 publications

(106 citation statements)

References 94 publications

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“…to treat digested piggery wasterwater and found that high removal efficiency of nutrients was achieved (95.91 % NH 4 + and 92.92 % TP, respectively). Additionally, the removal efficiencies of NH 4 + and TP were closely related to the survival probability of algae in different nutrient conditions (Lee et al 2012;Sanz-Luque et al 2013;Yan et al 2013). However, when the CTAB concentration was higher than 15 ng/L, the removal efficiency of both NH 4 + and TP significantly declined (p < 0.05), compared to that in the absence of CTAB.…”

Section: Resultsmentioning

confidence: 82%

Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis

Zhou

et al. 2016

Environ Sci Pollut Res

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Toxicants are generally harmful to biotechnology in wastewater treatment. However, trace toxicant can induce microbial hormesis, but to date, it is still unknown how this phenomenon affects nutrient removal during municipal wastewater treatment process. Therefore, this study focused on the effects of hormesis induced by cetyltrimethyl ammonium bromide (CTAB), a representative quaternary ammonium cationic surfactant, on nutrient removal by Chlorella vulgaris F1068. Results showed that when the concentration of CTAB was less than 10 ng/L, the cellular components chlorophyll a, proteins, polysaccharides, and total lipids increased by 10.11, 58.17, 38.78, and 11.87 %, respectively, and some enzymes in nutrient metabolism of algal cells, such as glutamine synthetase (GS), acid phosphatase (ACP), H(+)-ATPase, and esterase, were also enhanced. As a result, the removal efficiencies of ammonia nitrogen (NH4 (+)) and total phosphorus (TP) increased by 14.66 and 8.51 %, respectively, compared to the control during a 7-day test period. The underlying mechanism was mainly due to an enhanced photosynthetic activity of C. vulgaris F1068 indicated by the increase in chlorophyll fluorescence parameters (the value of Fv/Fm, ΦII, Fv/Fo, and rETR increased by 12.99, 7.56, 25.59, and 8.11 %, respectively) and adenylate energy charge (AEC) (from 0.68 to 0.72). These results suggest that hormesis induced by trace toxicants could enhance the nutrient removal, which would be further considered in the design of municipal wastewater treatment processes. Graphical abstract The schematic mechanism of C. vulgaris F1068 under CTAB induced hormesis. Green arrows ( ) represent the increase and the red arrow ( ) represents the decrease.

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Section: Resultsmentioning

confidence: 82%

Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis

Zhou

et al. 2016

Environ Sci Pollut Res

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“…The solely ketogenic amino acids, lysine and leucine, will be converted to acetyl-CoA and will presumably be used as substrate for the TCA cycle or contribute to pools for fatty acid synthesis. Interestingly, recent metabolomic studies that examined the dynamics of metabolite profiles under nitrogen stress identified the lysine degradation intermediate alpha-aminoadipate as a marker for nitrogen stress (8,9). Under various degrees of nitrogen stress, flux through the lysine pathway is very responsive (9).…”

Section: Lipid Metabolismmentioning

confidence: 99%

“…Now that its genome is fully sequenced (1) and largely annotated, it is accessible for largescale high-throughput investigative techniques like transcriptomics (2-4), proteomics (5-7), or metabolomics (8,9). Sometimes, to be as complete as possible, we have drawn reference to literature which is itself a prediction, relies on older techniques, or is available only for other related algae or plants; therefore, we urge the reader to use this minireview as a guide to compartmentalization and energetic constraints, rather than a definitive text.…”

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confidence: 99%

Central Carbon Metabolism and Electron Transport in Chlamydomonas reinhardtii: Metabolic Constraints for Carbon Partitioning between Oil and Starch

2013

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eThe metabolism of microalgae is so flexible that it is not an easy task to give a comprehensive description of the interplay between the various metabolic pathways. There are, however, constraints that govern central carbon metabolism in Chlamydomonas reinhardtii that are revealed by the compartmentalization and regulation of the pathways and their relation to key cellular processes such as cell motility, division, carbon uptake and partitioning, external and internal rhythms, and nutrient stress. Both photosynthetic and mitochondrial electron transfer provide energy for metabolic processes and how energy transfer impacts metabolism and vice versa is a means of exploring the regulation and function of these pathways. A key example is the specific chloroplast localization of glycolysis/gluconeogenesis and how it impacts the redox poise and ATP budget of the plastid in the dark. To compare starch and lipids as carbon reserves, their value can be calculated in terms of NAD(P)H and ATP. As microalgae are now considered a potential renewable feedstock, we examine current work on the subject and also explore the possibility of rerouting metabolism toward lipid production. Photosynthetic algae fix atmospheric carbon (CO 2 ) by using light energy to drive a series of chemical and redox reactions. This fixed carbon is transformed into reserve molecules that can be broken down at a later time to provide the cell with ATP, reducing power, and carbon skeletons. Starch, a polymer of glucose, is synthesized and degraded as a normal process in a light-dark cell cycle. Starch is also accumulated to prepare for gametogenesis, but it is not a prerequisite. The type and quantity of the reserve depend on environmental and cellular factors: stresses such as nutrient deprivation, salinity, temperature, and high light can be stimuli for starch accumulation and also for triacylglycerol (TAG) synthesis leading to lipid body accumulation in algae. Under nonstress conditions, starch would appear to be a preferential source of reserve in green algae as it is in plant leaves, whereas under stress conditions and in plant oil seeds, storage neutral lipids will accumulate to high levels.Photosynthesis is a tightly controlled process, from the capture of light energy to the conversion of this energy into ATP and reducing power (NADPH). ATP and NADPH feed the Calvin cycle, which is responsible for CO 2 fixation. In the absence of exogenous carbon supply, photosynthesis is the only source of energy, and CO 2 fixation provides carbon skeletons for all reactions in the cell. Tight control of the photosynthetic reactions is required to fit the downstream metabolic reactions in the chloroplast.We deliberately oriented our presentation and our choice of references toward Chlamydomonas reinhardtii, a unicellular green alga that has garnered much attention from the scientific community, primarily because it is haploid and the genetics have been extensively developed, but it has also proven to be a robust model system for the study of photosynthesis. No...

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“…Using the annotated C. reinhardtii genome (Merchant et al, 2007), the C. reinhardtii transcriptome was analyzed before and after N deprivation, which revealed multiple changes in gene expression that affect diverse parts of metabolism (Miller et al, 2010;Blaby et al, 2013;Goodenough et al, 2014;Schmollinger et al, 2014). In addition, proteomics have been used to profile the changes in protein expression during N deprivation in Phaeodactylum tricornutum (Yang et al, 2014), C. reinhardtii Longworth et al, 2012;Schmollinger et al, 2014), and Nannochloropsis oceanica (Dong et al, 2013), and metabolomics have been used to assess changes in metabolite pool sizes (Bölling and Fiehn, 2005;Lee et al, 2012). These and other studies point to wide-ranging changes in the structure and operation of the metabolic and other cellular networks.…”

mentioning

confidence: 99%

The Regulation of Photosynthetic Structure and Function during Nitrogen Deprivation in Chlamydomonas reinhardtii

Juergens

Deshpande²,

Lucker

et al. 2014

Plant Physiology

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The accumulation of carbon storage compounds by many unicellular algae after nutrient deprivation occurs despite declines in their photosynthetic apparatus. To understand the regulation and roles of photosynthesis during this potentially bioenergetically valuable process, we analyzed photosynthetic structure and function after nitrogen deprivation in the model alga Chlamydomonas reinhardtii. Transcriptomic, proteomic, metabolite, and lipid profiling and microscopic time course data were combined with multiple measures of photosynthetic function. Levels of transcripts and proteins of photosystems I and II and most antenna genes fell with differing trajectories; thylakoid membrane lipid levels decreased, while their proportions remained similar and thylakoid membrane organization appeared to be preserved. Cellular chlorophyll (Chl) content decreased more than 2-fold within 24 h, and we conclude from transcript protein and 13 C labeling rates that Chl synthesis was down-regulated both pre-and posttranslationally and that Chl levels fell because of a rapid cessation in synthesis and dilution by cellular growth rather than because of degradation. Photosynthetically driven oxygen production and the efficiency of photosystem II as well as P700 + reduction and electrochromic shift kinetics all decreased over the time course, without evidence of substantial energy overflow. The results also indicate that linear electron flow fell approximately 15% more than cyclic flow over the first 24 h. Comparing Calvin-Benson cycle transcript and enzyme levels with changes in photosynthetic 13 CO 2 incorporation rates also pointed to a coordinated multilevel down-regulation of photosynthetic fluxes during starch synthesis before the induction of high triacylglycerol accumulation rates.

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System Response of Metabolic Networks in Chlamydomonas reinhardtii to Total Available Ammonium

Cited by 94 publications

References 94 publications

Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis

Nutrient removal by Chlorella vulgaris F1068 under cetyltrimethyl ammonium bromide induced hormesis

Central Carbon Metabolism and Electron Transport in Chlamydomonas reinhardtii: Metabolic Constraints for Carbon Partitioning between Oil and Starch

The Regulation of Photosynthetic Structure and Function during Nitrogen Deprivation in Chlamydomonas reinhardtii

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