scholarly journals The effects of altered membrane sterol composition on oxidative phosphorylation in a haem mutant of Saccharomyces cerevisiae

1977 ◽  
Vol 166 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Anne M. Astin ◽  
J. M. Haslam
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Oxidative Phosphorylation ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Tween 80 ◽  
Growth Efficiency ◽  
Sterol Composition ◽  
Sterol Content

1. The sterol, unsaturated fatty acid and cytochrome contents of cells of a δ-aminolaevulinate synthase mutant of Saccharomyces cerevisiae are manipulated by growing the organism in media containing defined supplements of δ-aminolaevulinate and other porphyrin intermediates. 2. If unsaturated fatty acids are added to the growth medium as Tween 80, sterol content and respiratory cytochromes alone are manipulated. 3. In the presence of δ-aminolaevulinate (10–50mg/1) cells exhibit moderate to high respiratory activity, but growth yields are low, indicating a loss of oxidative phosphorylation. This is associated with the depletion of membrane lipids, either unsaturated fatty acids and sterols together or sterols alone. 4. Sterol depletion leads to the loss of coupled mitochondrial oxidative phosphorylation in vitro. 5. The lesion in oxidative phosphorylation is associated with an increase in the passive permeability of sterol-depleted mitochondria to protons. 6. Arrhenius plots of mitochondrial permeability to protons indicate that the activation energy for proton entry increases as the sterol content of the membranes decreases. 7. Studies on a cytoplasmic petite mutant isolated from strain ole-3, which lacks a functional membrane-bound protein-translocating adenosine triphosphatase, indicate that proton permeability of the petite mitochondria varies as a function of sterol composition in the same way as that of ole-3 grande mitochondria. This indicates that sterols alone are probably directly responsible for the increased proton entry, owing to a reorganization of the lipid in the membrane. 8. Supplemented ole-3 cells with a normal lipid composition and normal or higher than normal respiratory activities have a growth efficiency only 65% of that of the wild-type, indicating that a further lesion in energy metabolism may be present.

scholarly journals The effects of altered sterol composition on the mitochondrial adenine nucleotide transporter of Saccharomyces cerevisiae

1977 ◽  
Vol 166 (3) ◽  
pp. 559-563 ◽  
Author(s):  
J M Haslam ◽  
A M Astin ◽  
W W Nichols
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Binding Sites ◽  
Adenine Nucleotide ◽  
Tween 80 ◽  
Sterol Composition ◽  
Affinity Binding ◽  
Sterol Content ◽  
Macromolecular Synthesis ◽  
High Affinity

1. The membrane sterol composition of mitochondria of the ole-3 mutant of Saccharomyces cerevisiae was manipulated by growing the organism in the presence of Tween 80 (1%, W/V) plus defined supplements o- delta-aminolaevulinate. 2. Changes in mitochondrial sterol content induced considerable changes in the adenine nucleotide transporter. 3. As the sterol content was decreased, the affinity of the transporter for ATP did not alter significantly, but the rate of ATP uptake was greatly decreased, the total number of atractylate-sensitive binding sites diminished, and the proportion of high-affinity binding sites was decreased. 4. Since sterol depletion also uncouples oxidative phosphorylation [Astin & Haslam (1977) Biochem. J., 166, 287-298] and prevents the intramitochondrial generation of ATP, the decrease in the rate of ATP uptake by sterol-depleted mitochondria will cause a decrease in intramitochondrial ATP concentrations in vivo. This probably explains the inhibition of mitochondrial macromolecular synthesis that has previously been reported in lipid-depleted yeast mitochondria.

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.

scholarly journals Fluidization of Membrane Lipids Enhances the Tolerance of Saccharomyces cerevisiae to Freezing and Salt Stress

2006 ◽  
Vol 73 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Sonia Rodríguez-Vargas ◽  
Alicia Sánchez-García ◽  
Jose Manuel Martínez-Rivas ◽  
Jose Antonio Prieto ◽  
Francisca Randez-Gil
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Membrane Lipids ◽  
Fatty Acid Content ◽  
Unsaturation Index ◽  
Monounsaturated Fatty Acids ◽  
Yeast Cells ◽  
Proper Function ◽  
Wild Type

ABSTRACT Unsaturated fatty acids play an essential role in the biophysical characteristics of cell membranes and determine the proper function of membrane-attached proteins. Thus, the ability of cells to alter the degree of unsaturation in their membranes is an important factor in cellular acclimatization to environmental conditions. Many eukaryotic organisms can synthesize dienoic fatty acids, but Saccharomyces cerevisiae can introduce only a single double bond at the Δ9 position. We expressed two sunflower (Helianthus annuus) oleate Δ12 desaturases encoded by FAD2-1 and FAD2-3 in yeast cells of the wild-type W303-1A strain (trp1) and analyzed their effects on growth and stress tolerance. Production of the heterologous desaturases increased the content of dienoic fatty acids, especially 18:2Δ9,12, the unsaturation index, and the fluidity of the yeast membrane. The total fatty acid content remained constant, and the level of monounsaturated fatty acids decreased. Growth at 15°C was reduced in the FAD2 strains, probably due to tryptophan auxotrophy, since the trp1 (TRP1) transformants that produced the sunflower desaturases grew as well as the control strain did. Our results suggest that changes in the fluidity of the lipid bilayer affect tryptophan uptake and/or the correct targeting of tryptophan transporters. The expression of the sunflower desaturases, in either Trp+ or Trp− strains, increased NaCl tolerance. Production of dienoic fatty acids increased the tolerance to freezing of wild-type cells preincubated at 30°C or 15°C. Thus, membrane fluidity is an essential determinant of stress resistance in S. cerevisiae, and engineering of membrane lipids has the potential to be a useful tool of increasing the tolerance to freezing in industrial strains.

scholarly journals Anaerobic growth of Saccharomyces cerevisiae CEN.PK113-7D does not depend on synthesis or supplementation of unsaturated fatty acids

2019 ◽  
Vol 19 (6) ◽  
Author(s):  
Wijb J C Dekker ◽  
Sanne J Wiersma ◽  
Jonna Bouwknegt ◽  
Christiaan Mooiman ◽  
Jack T Pronk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Laboratory Strain ◽  
Tween 80 ◽  
Batch Cultivation ◽  
Anaerobic Growth ◽  
Growth Media ◽  
Yeast Viability

ABSTRACT In Saccharomyces cerevisiae, acyl-coenzyme A desaturation by Ole1 requires molecular oxygen. Tween 80, a poly-ethoxylated sorbitan-oleate ester, is therefore routinely included in anaerobic growth media as a source of unsaturated fatty acids (UFAs). During optimization of protocols for anaerobic bioreactor cultivation of this yeast, we consistently observed growth of the laboratory strain S. cerevisiae CEN.PK113-7D in media that contained the anaerobic growth factor ergosterol, but lacked UFAs. To minimize oxygen contamination, additional experiments were performed in an anaerobic chamber. After anaerobic precultivation without ergosterol and Tween 80, strain CEN.PK113-7D and a congenic ole1Δ strain both grew during three consecutive batch-cultivation cycles on medium that contained ergosterol, but not Tween 80. During these three cycles, no UFAs were detected in biomass of cultures grown without Tween 80, while contents of C10 to C14 saturated fatty acids were higher than in biomass from Tween 80-supplemented cultures. In contrast to its UFA-independent anaerobic growth, aerobic growth of the ole1Δ strain strictly depended on Tween 80 supplementation. This study shows that the requirement of anaerobic cultures of S. cerevisiae for UFA supplementation is not absolute and provides a basis for further research on the effects of lipid composition on yeast viability and robustness.

Inhibition of binding of gonadal steroids to serum binding proteins by non-esterified fatty acids: the influence of chain length and degree of unsaturation

1989 ◽  
Vol 120 (2) ◽  
pp. 175-179 ◽  
Author(s):  
C. Street ◽  
R. J. S. Howell ◽  
L. Perry ◽  
S. Al-Othman ◽  
T. Chard
Keyword(s):  
Fatty Acids ◽  
Protein Binding ◽  
Unsaturated Fatty Acids ◽  
Late Pregnancy ◽  
Sex Hormone Binding Globulin ◽  
Partial Purification ◽  
Normal Female ◽  
Esterified Fatty Acids ◽  
Vitro Binding

Abstract. The effect of non-esterified fatty acids (NEFA) on the in vitro binding of testosterone, 5-alpha dihydrotestosterone and estradiol E2 to sex hormone binding globulin (SHBG) was examined using pooled normal female serum, and SHBG and albumin fractions obtained from the partial purification of late pregnancy serum. A range of saturated and unsaturated fatty acids were examined for their effect on steroid-protein binding. In normal female serum, NEFA added at physiological concentrations disrupted steroid-protein binding. The shorter chain (C8–C12) saturated acids and the poly-unsaturated acids proved to be more effective inhibitors than the longer chain saturated or mono-unsaturated acids. The greatest inhibition was obtained with E2 whereas the binding of dihydrotestosterone was least affected. With partially purified SHBG, the same concentrations of NEFA were less effective at inhibiting the binding of dihydrotestosterone and testosterone but elicited the same effect with E2. The binding of steroids to albumin appeared to be unaffected by these concentrations of NEFA.

Evidence for a novel pathway for the targeting of a Saccharomyces cerevisiae peroxisomal protein belonging to the isomerase/hydratase family

2000 ◽  
Vol 113 (3) ◽  
pp. 533-544
Author(s):  
I.V. Karpichev ◽  
G.M. Small
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Beta Oxidation ◽  
Peroxisomal Protein ◽  
Intracellular Targeting ◽  
Targeting Signals ◽  
Peroxisome Targeting Signals

We, and others, have identified a novel Saccharomyces cerevisiae peroxisomal protein that belongs to the isomerase/hydratase family. The protein, named Dci1p, shares 50% identity with Eci1p, a delta(3)-cis-delta(2)-trans-enoyl-CoA isomerase that acts as an auxiliary enzyme in the beta-oxidation of unsaturated fatty acids. Both of these proteins are localized to peroxisomes, and both contain motifs at their amino- and carboxyl termini that resemble peroxisome targeting signals (PTS) 1 and 2. However, we demonstrate that the putative type 1 signaling motif is not required for the peroxisomal localization of either of these proteins. Furthermore, the correct targeting of Eci1p and Dci1p occurs in the absence of the receptors for the type 1 or type 2 peroxisome targeting pathway. Together, these data suggest a novel mechanism for the intracellular targeting of these peroxisomal proteins.

Sign in / Sign up

Export Citation Format

Share Document