Physiological functions of pyruvate:NADP+ oxidoreductase and 2-oxoglutarate decarboxylase in <i>Euglena gracilis</i> under aerobic and anaerobic conditions

Nakazawa, Masami; Hayashi, Ryuta; Takenaka, Shigeo; Inui, Hiroshi; Ishikawa, Takahiro; Ueda, Mitsuhiro; Sakamoto, Tatsuji; Nakano, Yoshiaki; Miyatake, Kazutaka

doi:10.1080/09168451.2017.1318696

Cited by 16 publications

(17 citation statements)

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“…gracilis cells developed mitochondria in those conditions, we analyzed mitochondrial protein content. We used an antibody against pyruvate: NADP+ oxidoreductase (PNO) which is involved in the formation of acetyl-CoA and localizes in mitochondria ( Nakazawa et al, 2017 ). As expected, under heterotrophic conditions, E .…”

Section: Resultsmentioning

confidence: 99%

Alterations of Membrane Lipid Content Correlated With Chloroplast and Mitochondria Development in Euglena gracilis

et al. 2018

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Euglenoids are unique protists that can grow photoautotrophically, photomixotrophically, and heterotrophically. Here we grew Euglena gracilis under these different growth conditions and determined cellular contents of seven membrane lipids and one storage lipid (triacylglycerol), which account for more than 94 mol% of total membrane lipids. We also describe the relationship among chloroplast and mitochondria developments with lipid contents, protein contents, and oxygen evolution/consumption rates. In photoautotrophic growth conditions, E. gracilis cells accumulated chlorophyll, photosynthetic proteins, and glycolipids typical to thylakoid membranes. The same occurred for the cells grown under photomixotrophic conditions with higher respiration rates. In heterotrophic conditions, E. gracilis cells had higher respiration rates compared to cells grown in other conditions with the accumulation of pyruvate: NADP+ oxidoreductase, a mitochondrial protein and phospholipid common in mitochondria. Cells were also observed using a confocal laser scanning microscope and found to show more chlorophyll autofluorescence when grown photoautotrophically and photomixotrophycally, and fluorescence of MitoTracker when grown photomixotrophically and heterotrophically. These results suggest that under illumination, E. gracilis develops functional thylakoid membranes with membrane lipids and proteins for photosynthesis. In the medium with glucose, the cells develop mitochondria with phospholipids and proteins for respiration. Possible application based on lipid analysis for the enhancement of wax ester or alkene synthesis is discussed.

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Section: Resultsmentioning

confidence: 99%

Alterations of Membrane Lipid Content Correlated With Chloroplast and Mitochondria Development in Euglena gracilis

et al. 2018

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“…Euglena gracilis SM‐ZK, a nonphotosynthetic mutant strain , was cultured in Koren–Hutner medium containing glucose as the major carbon source with aeration at 27 °C for 3 or 4 days until the late logarithmic or early stationary phase of growth. Anaerobic treatment was performed as follows: an aliquot (2 mL) of the aerobic cell culture was dispensed into 5 mL plastic tube and bubbled with argon gas for 1 min.…”

Section: Methodsmentioning

confidence: 99%

Anaerobic respiration coupled with mitochondrial fatty acid synthesis in wax ester fermentation by Euglena gracilis

et al. 2018

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In Euglena gracilis , wax ester fermentation produces ATP during anaerobiosis. Here, we report that anaerobic wax ester production is suppressed when the mitochondrial electron transport chain complex I is inhibited by rotenone, whereas it is increased by the uncoupler carbonyl cyanide m ‐chlorophenylhydrazone ( CCCP ). The ADP / ATP ratio in anaerobic cells is elevated by treatment with either rotenone or CCCP . Gene silencing experiments indicate that acyl‐CoA dehydrogenase, electron transfer flavoprotein ( ETF ), and rhodoquinone ( RQ ) participate in wax ester production. These results suggest that fatty acids are synthesized in mitochondria by the reversal of β‐oxidation, where trans ‐2‐enoyl‐CoA is reduced mainly by acyl‐CoA dehydrogenase using the electrons provided by NADH via the electron transport chain complex I, RQ , and ETF , and that ATP production is highly supported by anaerobic respiration utilizing trans ‐2‐enoyl‐CoA as a terminal electron acceptor.

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“…Pyruvate Dehydrogenase (NAD complex 1.2.4.1, NADP+ EC 1.2.1.51). In E. gracilis the conventional NAD + pyruvate dehydrogenase complex only contributes around 1% of the activity and instead an NADP + -dependent pyruvate dehydrogenase is used to produce the majority of the acetyl-CoA from pyruvate [70]. This latter enzyme has been detected in the mitochondrial fractions of E. gracilis [71,72,73] and all three component polypeptides are predicted to be targeted to the mitochondria.…”

Section: Resultsmentioning

confidence: 99%

Euglena Central Metabolic Pathways and Their Subcellular Locations

et al. 2019

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Euglenids are a group of algae of great interest for biotechnology, with a large and complex metabolic capability. To study the metabolic network, it is necessary to know where the component enzymes are in the cell, but despite a long history of research into Euglena, the subcellular locations of many major pathways are only poorly defined. Euglena is phylogenetically distant from other commonly studied algae, they have secondary plastids bounded by three membranes, and they can survive after destruction of their plastids. These unusual features make it difficult to assume that the subcellular organization of the metabolic network will be equivalent to that of other photosynthetic organisms. We analysed bioinformatic, biochemical, and proteomic information from a variety of sources to assess the subcellular location of the enzymes of the central metabolic pathways, and we use these assignments to propose a model of the metabolic network of Euglena. Other than photosynthesis, all major pathways present in the chloroplast are also present elsewhere in the cell. Our model demonstrates how Euglena can synthesise all the metabolites required for growth from simple carbon inputs, and can survive in the absence of chloroplasts.

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Physiological functions of pyruvate:NADP+ oxidoreductase and 2-oxoglutarate decarboxylase in Euglena gracilis under aerobic and anaerobic conditions

Cited by 16 publications

References 44 publications

Alterations of Membrane Lipid Content Correlated With Chloroplast and Mitochondria Development in Euglena gracilis

Alterations of Membrane Lipid Content Correlated With Chloroplast and Mitochondria Development in Euglena gracilis

Anaerobic respiration coupled with mitochondrial fatty acid synthesis in wax ester fermentation by Euglena gracilis

Euglena Central Metabolic Pathways and Their Subcellular Locations

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