The role of malic enzyme in the regulation of lipid accumulation in filamentous fungi

The properties of ATP:citrate lyase, malic enzyme, and AMP deaminase have been investigated in Rhodosporidium toruloides CBS 14. ATP:citrate lyase had a molecular size of 480 000 daltons and apparent Km for citrate and ATP of 0.19 mM and 0.15 mM, respectively. The enzyme was inhibited by ADP, glucose 6-phosphate, palmitoyl-CoA, and oleoyl-CoA. [Formula: see text] ions showed a 95% stimulation of activity at nonsaturating concentrations (0.1 mM) of citrate. Malic enzyme had a molecular size of 205 000 daltons and an apparent Km for malate of 0.7 mM. The enzyme was only weakly inhibited by citrate, pyruvate, oxaloacetate, and ATP but no metabolite was found which exerted a significant regulatory control over the enzyme. However this enzyme could be used as the principal, if not sole, source of NADPH needed for fatty acid biosynthesis. The role of this enzyme and the central position of malate as a key metabolite in determining how lipid accumulation could be initiated and then sustained is discussed. AMP deaminase was detected in low activities but was fourfold higher in nitrogen-limited cells. The possible role of this enzyme in degrading AMP, regulating cellular energy charge, and supplementing [Formula: see text] pools in this yeast is also discussed.

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The Role of Lipids, Lipid Metabolism and Ectopic Lipid Accumulation in Axon Growth, Regeneration and Repair after CNS Injury and Disease

Cells ◽

10.3390/cells10051078 ◽

2021 ◽

Vol 10 (5) ◽

pp. 1078

Author(s):

Debasish Roy ◽

Andrea Tedeschi

Keyword(s):

Nervous System ◽

Lipid Metabolism ◽

Lipid Accumulation ◽

Axon Regeneration ◽

Axon Growth ◽

The Body ◽

Cns Repair ◽

Cord Injury ◽

Cns Trauma

Axons in the adult mammalian nervous system can extend over formidable distances, up to one meter or more in humans. During development, axonal and dendritic growth requires continuous addition of new membrane. Of the three major kinds of membrane lipids, phospholipids are the most abundant in all cell membranes, including neurons. Not only immature axons, but also severed axons in the adult require large amounts of lipids for axon regeneration to occur. Lipids also serve as energy storage, signaling molecules and they contribute to tissue physiology, as demonstrated by a variety of metabolic disorders in which harmful amounts of lipids accumulate in various tissues through the body. Detrimental changes in lipid metabolism and excess accumulation of lipids contribute to a lack of axon regeneration, poor neurological outcome and complications after a variety of central nervous system (CNS) trauma including brain and spinal cord injury. Recent evidence indicates that rewiring lipid metabolism can be manipulated for therapeutic gain, as it favors conditions for axon regeneration and CNS repair. Here, we review the role of lipids, lipid metabolism and ectopic lipid accumulation in axon growth, regeneration and CNS repair. In addition, we outline molecular and pharmacological strategies to fine-tune lipid composition and energy metabolism in neurons and non-neuronal cells that can be exploited to improve neurological recovery after CNS trauma and disease.

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Role of the mitochondrial citrate-oxoglutarate carrier in lipid accumulation in the oleaginous fungus Mortierella alpina

Biotechnology Letters ◽

10.1007/s10529-021-03133-x ◽

2021 ◽

Author(s):

Fengzhu Ling ◽

Xin Tang ◽

Hao Zhang ◽

Yong Q. Chen ◽

Jianxin Zhao ◽

...

Keyword(s):

Lipid Accumulation ◽

Mortierella Alpina ◽

Oleaginous Fungus ◽

Oxoglutarate Carrier

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Role of Pyruvate Carboxylase, Phosphoenolpyruvate Carboxykinase, and Malic Enzyme during Growth and Sporulation of Bacillus subtilis

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)43509-6 ◽

1973 ◽

Vol 248 (17) ◽

pp. 6062-6070

Author(s):

Martin D. Diesterhaft ◽

Ernst Freese

Keyword(s):

Bacillus Subtilis ◽

Malic Enzyme ◽

Pyruvate Carboxylase ◽

Phosphoenolpyruvate Carboxykinase

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The role of malic enzyme as the provider of NADPH in oleaginous microorganisms: a reappraisal and unsolved problems

Biotechnology Letters ◽

10.1007/s10529-014-1532-3 ◽

2014 ◽

Vol 36 (8) ◽

pp. 1557-1568 ◽

Cited By ~ 134

Author(s):

Colin Ratledge

Keyword(s):

Malic Enzyme ◽

Oleaginous Microorganisms

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Glucose stimulates transcription of fatty acid synthase and malic enzyme in avian hepatocytes

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1998.274.3.e493 ◽

1998 ◽

Vol 274 (3) ◽

pp. E493-E501 ◽

Cited By ~ 2

Author(s):

F. Bradley Hillgartner ◽

Tina Charron

Keyword(s):

Fatty Acid ◽

High Fat Diet ◽

Malic Enzyme ◽

Fatty Acid Synthase ◽

Primary Cultures ◽

Pentose Phosphate ◽

Mrna Abundance ◽

Low Fat Diet ◽

Low Carbohydrate

Transcription of fatty acid synthase (FAS) and malic enzyme (ME) in avian liver is low during starvation or feeding a low-carbohydrate, high-fat diet and high during feeding a high-carbohydrate, low-fat diet. The role of glucose in the nutritional control of FAS and ME was investigated by determining the effects of this metabolic fuel on expression of FAS and ME in primary cultures of chick embryo hepatocytes. In the presence of triiodothyronine, glucose (25 mM) stimulated an increase in the activity and mRNA abundance of FAS and ME. These effects required the phosphorylation of glucose to glucose 6-phosphate but not further metabolism downstream of the aldolase step of the glycolytic pathway. Xylitol mimicked the effects of glucose on FAS and ME expression, suggesting that an intermediate of the pentose phosphate pathway may be involved in mediating this response. The effects of glucose on the mRNA abundance of FAS and ME were accompanied by similar changes in transcription of FAS and ME. These data support the hypothesis that glucose plays a role in mediating the effects of nutritional manipulation on transcription of FAS and ME in liver.

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Influence of N-limitation on Malic Enzyme Isoforms and Lipogenesis of Cunninghamella bainieri 2A1

Jurnal Teknologi ◽

10.11113/jt.v67.1861 ◽

2014 ◽

Vol 67 (1) ◽

Cited By ~ 1

Author(s):

Aidil Abdul Hamid ◽

Shuwahida Shuib ◽

Ekhlass M. Taha ◽

Othman Omar ◽

Mohd Sahaid Khalil ◽

...

Keyword(s):

Lipid Content ◽

Lipid Accumulation ◽

Malic Enzyme ◽

Lipid Synthesis ◽

Lower Activity ◽

Ammonium Tartrate ◽

Ammonium Ions ◽

Activity Staining ◽

N Limitation ◽

Enzyme Isoforms

The influence of the presence of ammonium ions in growth culture on malic enzyme (ME) isoforms activity and lipogenesis in Cunninghamella bainieri 2A1 was investigated. The fungus was cultivated in a nitrogen-limiting medium for 120 h at 30oC under two conditions. One of the cultures was intermittently fed with ammonium tartrate to maintain the ammonium concentrations above 0.5 g/L. The second culture was performed without any feeding to allow N limitation, thus promoting lipid accumulation. Activity staining of ME isoforms was carried out for both cultures. The culture which was not intermittently fed with ammonium tartrate achieved a maximum lipid content of 35% (g/g biomass) at 48 h. This culture possessed five ME isoforms (A, B, C, D and E) with isoform E showing a parallel correlation to lipid accumulation profile. In contrast, intensity of bands representing isoform D decreased as lipid accumulated. No appreciable differences of all other isoforms were observed. However, the culture which was intermittently fed with ammonium tartrate, accumulated only up to 16% lipid (g/g biomass). All isoforms were present but with a more pronounced activity of isoform D and a lower activity of isoform E was observed. These findings support further evidence that isoform E is the key isoform for lipid synthesis in C. bainieri 2A1.

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