scholarly journals Biogenesis of mitochondria*. The effects of altered membrane lipid composition on cation transport by mitochondria of Saccharomyces cerevisiae

1973 ◽  
Vol 134 (4) ◽  
pp. 949-957 ◽  
Author(s):  
J. M. Haslam ◽  
T. W. Spithill ◽  
Anthony W. Linnane ◽  
J. B. Chappell
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Oxidative Phosphorylation ◽  
Free Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Cation Transport ◽  
Lipid Phase ◽  
Yeast Mitochondria ◽  
Passive Permeability

1. The fatty acid composition of the membrane lipids of a fatty acid desaturase mutant of Saccharomyces cerevisiae was manipulated by growing the organism in a medium containing defined fatty acid supplements. 2. Mitochondria were obtained whose fatty acids contain between 20% and 80% unsaturated fatty acids. 3. Mitochondria with high proportions of unsaturated fatty acids in their lipids have coupled oxidative phosphorylation with normal P/O ratios, accumulate K+ ions in the presence of valinomycin and an energy source, and eject protons in an energy-dependent fashion. 4. If the unsaturated fatty acid content of the mitochondrial fatty acids is lowered to 20%, the mitochondria simultaneously lose active cation transport and the ability to couple phosphorylation to respiration. 5. The loss of energy-linked reactions is accompanied by an increased passive permeability of the mitochondria to protons. 6. Free fatty acids uncouple oxidative phosphorylation in yeast mitochondria and the effect is reversed by bovine serum albumin. 7. The free fatty acid contents of yeast mitochondria are unaffected by depletion of unsaturated fatty acids, and free fatty acids are not responsible for the uncoupling of oxidative phosphorylation in organelles depleted in unsaturated fatty acids. 8. It is suggested that the loss of energy-linked reactions in yeast mitochondria that are depleted in unsaturated fatty acids is a consequence of the increased passive permeability to protons, and is caused by a change in the physical properties of the lipid phase of the inner mitochondrial membrane.

Chemical Alterations in Fish Tissue During Storage at Low Temperatures

1969 ◽  
Vol 52 (5) ◽  
pp. 904-910 ◽  
Author(s):  
Garnett Wood ◽  
Lane Hintz ◽  
Harold Salwin
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Low Temperatures ◽  
Unsaturated Fatty Acids ◽  
Storage Temperature ◽  
Neutral Lipids ◽  
Fish Tissue ◽  
Protective Mechanism ◽  
Polyunsaturated Acids

Abstract Chemical changes that occur in the proteins, nucleotides, and lipids of fish tissue during storage at low temperatures were investigated. Homogenized tissue, prepared from fresh rock-fish (striped hass, Roccus species), was stored up to six days at temperatures from -10° to 4°C and then analyzed. At 0°C and below, the solubility of myofibrillar proteins decreased. There were also changes in polyacrylamide gel electrophoretic patterns of protein extracts. The total nucleotide content decreased rapidly at all temperatures. The lipids were extracted from each sample and separated into neutral lipids, phospholipids, and free fatty acids by column chromatography. The fatty acid composition of each fraction was determined by gas chromatography. In the fresh tissue, polyunsaturated acids occurred in greatest proportion in the free fatty acid and phospholipid fractions, whereas inono-unsaturated acids were inofe highly concentrated in the neutral lipids. The percentages of saturated acids were approximately the same in all fractions. During storage, there were considerably larger losses of individual acids from phospholipids than from neutral lipids. The polyunsaturated acids of the phospholipid fraction were affected most. Over 10% of these aeids were lost in six days at ice temperature, but only a small proportion of the losses was accounted for by increases in free fatty acids. Oxidative proo esses may account for the imbalance because the rate of oxidation, as measured by the thio-barbituric acid test, increased with storage temperature in the same manner as the rale at which unsaturated fatty acids were lost from the pliospliolipuls. Losses of polyunsaturated acids from the neutral lipids were much smaller, suggesting a selectively protective mechanism or environment in that fraction. The changes in the phospholipid fatty acids may provide the basis for useful objective tests of fish lecomposilion.

scholarly journals Expressing a cytosolic pyruvate dehydrogenase complex to increase free fatty acid production in Saccharomyces cerevisiae

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Yiming Zhang ◽  
Mo Su ◽  
Ning Qin ◽  
Jens Nielsen ◽  
Zihe Liu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Pyruvate Dehydrogenase ◽  
Unsaturated Fatty Acids ◽  
Pyruvate Dehydrogenase Complex ◽  
Cell Factory ◽  
Acetyl Coa ◽  
Fatty Acid Production

Abstract Background Saccharomyces cerevisiae is being exploited as a cell factory to produce fatty acids and their derivatives as biofuels. Previous studies found that both precursor supply and fatty acid metabolism deregulation are essential for enhanced fatty acid synthesis. A bacterial pyruvate dehydrogenase (PDH) complex expressed in the yeast cytosol was reported to enable production of cytosolic acetyl-CoA with lower energy cost and no toxic intermediate. Results Overexpression of the PDH complex significantly increased cell growth, ethanol consumption and reduced glycerol accumulation. Furthermore, to optimize the redox imbalance in production of fatty acids from glucose, two endogenous NAD+-dependent glycerol-3-phosphate dehydrogenases were deleted, and a heterologous NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase was introduced. The best fatty acid producing strain PDH7 with engineering of precursor and co-factor metabolism could produce 840.5 mg/L free fatty acids (FFAs) in shake flask, which was 83.2% higher than the control strain YJZ08. Profile analysis of free fatty acid suggested the cytosolic PDH complex mainly resulted in the increases of unsaturated fatty acids (C16:1 and C18:1). Conclusions We demonstrated that cytosolic PDH pathway enabled more efficient acetyl-CoA provision with the lower ATP cost, and improved FFA production. Together with engineering of the redox factor rebalance, the cytosolic PDH pathway could achieve high level of FFA production at similar levels of other best acetyl-CoA producing pathways.

scholarly journals Expressing a Cytosolic Pyruvate Dehydrogenase Complex to Increase Free Fatty Acid Production in Saccharomyces Cerevisiae

2020 ◽  
Author(s):  
Yiming Zhang ◽  
Mo Su ◽  
Ning Qin ◽  
Jens Nielsen ◽  
Zihe Liu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Pyruvate Dehydrogenase ◽  
Unsaturated Fatty Acids ◽  
Pyruvate Dehydrogenase Complex ◽  
Cell Factory ◽  
Acetyl Coa ◽  
Fatty Acid Production

Abstract Background Saccharomyces cerevisiae is being exploited as a cell factory to produce fatty acids and their derivatives as biofuels. Previous studies found that both precursor supply and fatty acid metabolism deregulation are essential for enhanced fatty acid synthesis. A bacterial pyruvate dehydrogenase (PDH) complex expressed in the yeast cytosol was reported to enable production of cytosolic acetyl-CoA with lower energy cost and no toxic intermediate. Results Overexpression of the PDH complex significantly increased cell growth, ethanol consumption and reduced glycerol accumulation. Furthermore, to optimize the redox imbalance in production of fatty acids from glucose, two endogenous NAD+-dependent glycerol-3-phosphate dehydrogenases were deleted, and a heterologous NADP+-dependent glyceraldehyde-3-phosphate dehydrogenase was introduced. The final strain with engineering of precursor and co-factor metabolism could produce 840.5 mg/L free fatty acid in shake flask, which was 83.2% higher than the control strain. Profile analysis of free fatty acid suggested the cytosolic PDH complex mainly resulted in the increases of unsaturated fatty acids (C16:1 and C18:1). Conclusions We demonstrated that cytosolic PDH pathway enabled more efficient acetyl-CoA provision with the lower ATP cost, and improved FFA production. Together with engineering of the redox factor rebalance, the cytosolic PDH pathway could achieve high level of FFA production at similar levels of other best acetyl-CoA producing pathways.

Effects of unsaturated fatty acid deprivation on neutral lipid synthesis in Saccharomyces cerevisiae

1982 ◽  
Vol 152 (2) ◽  
pp. 747-756
Author(s):  
T M Buttke ◽  
A L Pyle
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Lipid Metabolism ◽  
Cell Growth ◽  
Unsaturated Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Lipid Synthesis ◽  
Yeast Cells

The effects of unsaturated fatty acid deprivation on lipid synthesis in Saccharomyces cerevisiae strain GL7 were determined by following the incorporation of [14C]acetate. Compared to yeast cells grown with oleic acid, unsaturated fatty acid-deprived cells contained 200 times as much 14C label in squalene, with correspondingly less label in 2,3-oxidosqualene and 2,3;22,23-dioxidosqualene. Cells deprived of either methionine or cholesterol did not accumulate squalene, demonstrating that the effect of unsaturated fatty acid starvation on squalene oxidation was not due to an inhibition of cell growth. Cells deprived of olefinic supplements displayed additional changes in lipid metabolism: (i) an increase in 14C-labeled diacylglycerides, (ii) a decrease in 14C-labeled triacylglycerides, and (iii) increased levels of 14C-labeled decanoic and dodecanoic fatty acids. The changes in squalene oxidation and acylglyceride metabolism in unsaturated fatty acid-deprived cells were readily reversed by adding oleic acid. Pulse-chase studies demonstrated that the [14C]squalene and 14C-labeled diacylglycerides which accumulated during starvation were further metabolized when cells were resupplemented with oleic acid. These results demonstrate that unsaturated fatty acids are essential for normal lipid metabolism in yeasts.

The effect of fatty acids on the developmental direction of Strongyloides ratti first-stage larvae

1989 ◽  
Vol 63 (2) ◽  
pp. 102-106 ◽  
Author(s):  
Takeya Minematsu ◽  
Tatsuyuki Mimori ◽  
Mitsuhiro Tanaka ◽  
Isao Tada
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Free Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Physiological Changes ◽  
Infective Larvae ◽  
Third Stage ◽  
Developmental Course

ABSTRACTThe effect of fatty acids was studied on the developmental direction of Strongyloides ratti first-stage larvae (L1). The proportion of third-stage infective larvae increased markedly when L1 were cultured in faeces with added fatty acids such as palmitic (C16), stearic (C18), oleic (C18:1) and linoleic (C18:2) acids. Unsaturated fatty acids were more effective than saturated ones. Moreover, the proportion of infective larvae increased with quantity of linoleic acid but the triacylglycerols of any fatty acid had no effect. These results suggest that these free fatty acids cause physiological changes that determine the developmental course of L1 of S. ratti in nature.

scholarly journals Expressing a cytosolic pyruvate dehydrogenase complex to increase free fatty acid production in Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Yiming Zhang ◽  
Mo Su ◽  
Ning Qin ◽  
Jens Nielsen ◽  
Zihe Liu
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Pyruvate Dehydrogenase ◽  
Unsaturated Fatty Acids ◽  
Pyruvate Dehydrogenase Complex ◽  
Cell Factory ◽  
Acetyl Coa ◽  
Fatty Acid Production

Abstract Background Saccharomyces cerevisiae is being exploited as a cell factory to produce fatty acids and their derivatives as biofuels. Previous studies found that both precursor supply and fatty acid metabolism deregulation are essential for enhanced fatty acid synthesis. A bacterial pyruvate dehydrogenase (PDH) complex expressed in the yeast cytosol was reported to enable production of cytosolic acetyl-CoA with lower energy cost and no toxic intermediate. Results Overexpression of the PDH complex significantly increased cell growth, ethanol consumption and reduced glycerol accumulation. Furthermore, to optimize the redox imbalance in production of fatty acids from glucose, two endogenous NAD + -dependent glycerol-3-phosphate dehydrogenases were deleted, and a heterologous NADP + -dependent glyceraldehyde-3-phosphate dehydrogenase was introduced. The best fatty acid producing strain PDH7 with engineering of precursor and co-factor metabolism could produce 840.5 mg/L free fatty acids (FFAs) in shake flask, which was 83.2% higher than the control strain YJZ08. Profile analysis of free fatty acid suggested the cytosolic PDH complex mainly resulted in the increases of unsaturated fatty acids (C16:1 and C18:1). Conclusions We demonstrated that cytosolic PDH pathway enabled more efficient acetyl-CoA provision with the lower ATP cost, and improved FFA production. Together with engineering of the redox factor rebalance, the cytosolic PDH pathway could achieve high level of FFA production at similar levels of other best acetyl-CoA producing pathways.

scholarly journals Lipid oxidative changes in traditional dry fermented sausage Petrovská klobása during storage

2014 ◽  
Vol 68 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Branislav Sojic ◽  
Ljiljana Petrovic ◽  
Anamarija Mandic ◽  
Ivana Sedej ◽  
Natalija Dzinic ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Storage Period ◽  
Fermented Sausage ◽  
Dry Fermented Sausage

The influence of drying and ripeninig conditions (traditional and industrial) in the production of dry fermented sausage Petrovsk? klob?sa, on fatty-acid composition and oxidative changes in lipids, during 7 months of storage, was investigated. During the storage period, the sum of unsaturated fatty acids and the content of free fatty acids were significantly higher (p<0.05), while the content of malondialdehyde was significantly lower in the sausage subjected to traditional conditions of drying and ripening. At the end of the storage period, contents of pentanal and hexanal in the sausage subjected to traditional conditions of drying and ripening (4.03 ?g/g and 1.67 ?g/g, respectively) were significantly lower (p<0.05) in comparison with these contents in the sausage subjected to industrial conditions of drying and ripening. Traditional conditions of drying and ripening at lower temperatures have led to lower oxidative changes in lipids in traditional dry fermented sausage Petrovsk? klob?sa during storage period.

Phase properties of membranes after freezing injury in winter wheat

1985 ◽  
Vol 63 (12) ◽  
pp. 2274-2277 ◽  
Author(s):  
Edward J. Kendall ◽  
Bryan D. McKersie ◽  
Robert H. Stinson
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Structural Change ◽  
Free Fatty Acids ◽  
Membrane Fraction ◽  
Freezing Stress ◽  
Freezing Injury ◽  
Membrane Properties ◽  
Lipid Phase ◽  
Total Lipid Extract

The structural and compositional changes which occur in cellular membranes after freezing stress were examined in a microsomal membrane fraction from the crown tissue of 7-day-old, nonacclimated Triticum aestivum L. cv. Fredrick seedlings, which were frozen to a lethal temperature of −12 °C. The freezing treatment induced a lipid phase separation and increased the gel to liquid – crystalline phase transition temperature of the isolated membrane fraction from 25 to 65 °C as detected by wide-angle X-ray diffraction. This structural change was not accompanied by significant changes in the fatty acid saturation of the total lipid extract or by changes in the free sterol components, but a 13-fold increase in the free fatty acid – phospholipid ratio was observed in the membranes from the freeze-stressed tissue. It is proposed that the accumulations of free fatty acids and other phospholipid degradation products in the membrane are factors relating to the formation of extensive gel-phase domains and that this structural change contributes to the changes in membrane properties, such as loss of semipermeability and osmotic responsiveness, which are typically observed after freezing stress. Possible mechanisms leading to the accumulation of free fatty acids are discussed.

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