Quantitative effects of unsaturated fatty acids in microbial mutants. VI. Selective growth responses of yeast and bacteria to cis-octadecenoate isomers

1976 ◽  
Vol 54 (8) ◽  
pp. 736-745 ◽  
Author(s):  
John B. Ohlrogge ◽  
Eugene D. Barber ◽  
William E. M. Lands ◽  
F. D. Gunstone ◽  
I. A. Ismail
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Ethylenic Bond ◽  
Yeast Cells ◽  
Nutritional Requirement ◽  
Bacterial Cells ◽  
Growth Responses ◽  
Cellular Lipids ◽  
Acyl Chains ◽  
Extensive Growth

The full series of positional isomers of cis-octadecenoate were tested for their suitability in meeting the nutritional requirement for unsaturated fatty acids by mutants of Escherichia coli and Saccharomyces cerevisiae that were unable to synthesize unsaturated fatty acids.Quantitative comparisons of the efficiencies of the various isomers showed a range from 0–48 cells per femtomole for the prokaryotic cells and 0–5 for eukaryotic cells. The Δ5 isomer was much more effective than the Δ6 isomer with the bacterial cells whereas the reverse was true with the yeast cells. In general, isomers containing a cis ethylenic bond between carbons 7 and 12 were able to support extensive growth of either type of mutant.Since all of the various isomers were incorporated into cellular lipids by both types of microorganism, the different efficiencies observed in supporting growth were not a simple reflection of the inability of an acid to be esterified. The differences may reflect the suitability of the resultant esterified product to function as a normal membrane lipid.The contents of various fatty acids in the cellular phospholipids when growth ceases may have a linearly cumulative relationship to the degree of expansion of the acyl chains.

scholarly journals Lipid remodelling during epididymal maturation of rat spermatozoa. Enrichment in plasmenylcholines containing long-chain polyenoic fatty acids of the n-9 series

1992 ◽  
Vol 283 (1) ◽  
pp. 235-241 ◽  
Author(s):  
M I Aveldaño ◽  
N P Rotstein ◽  
N T Vermouth
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Acyl Chain ◽  
Sperm Maturation ◽  
High Concentration ◽  
Lipid Domain ◽  
Choline Glycerophospholipids ◽  
Epididymal Maturation ◽  
Acyl Chains ◽  
Long Chain

In their transit from the caput to the cauda segments of the epididymis, rat spermatozoa undergo significant modifications in lipid content and composition. The amount of lipid phosphorus per cell decreases, and most lipid classes show specific changes in their constituent fatty acids. A depletion of phosphatidylcholine and phosphatidylethanolamine, concomitant with a virtually unchanged amount of the corresponding plasmalogens, are the major alterations, plasmenylcholine thereby becoming the major phospholipid. Diphosphatidylglycerol, sphingomyelin and the phosphoinositides decrease to a lesser extent or do not change at all, also resulting in relative increases with sperm maturation. Concerning the fatty acids, the proportions of oleate (C18:1, n-9) and linoleate (C18:2, n-6) in most lipids decrease on movement of sperm from caput to cauda, augmenting in turn the proportions of longer-chain (C20 to C24) and more unsaturated fatty acids. Docosapentaenoate (C22:5, n-6) is a major acyl chain present in all lipids at both stages, but uncommon long-chain polyenoic fatty acids of the n-9 series are also present, being almost exclusively found in the choline glycerophospholipids. These fatty acids are found to undergo the most significant changes during sperm maturation. They are minor components of plasmenylcholine in immature spermatozoa, but increase severalfold on maturation, representing more than half of the acyl chains of this major lipid in cells from the cauda. The high concentration of n-9 polyenes in mature sperm plasmenylcholine raises intriguing questions on the possible role epididymal cells may play in providing spermatozoa with such an unusual phospholipid. These plasmenylcholines could contribute to the characteristic lipid domain organization of the mature spermatozoa plasma membrane.

scholarly journals Unsaturated fatty acids augment protein transport via the SecA:SecYEG translocon

2021 ◽  
Author(s):  
Michael Kamel ◽  
Maryna Löwe ◽  
Stephan Schott-Verdugo ◽  
Holger Gohlke ◽  
Alexej Kedrov
Keyword(s):  
Fatty Acids ◽  
Protein Transport ◽  
Unsaturated Fatty Acids ◽  
Lipid Membrane ◽  
Cell Envelope ◽  
Membrane Surface ◽  
Bacterial Cells ◽  
Hydrophobic Core ◽  
Membrane Composition ◽  
Dynamics Simulations

AbstractThe translocon SecYEG forms the primary protein-conducting channel in the cytoplasmic membrane of bacteria, and the associated ATPase SecA provides the energy for the transport of secretory and cell envelope protein precursors. The translocation requires negative charge at the lipid membrane surface, but its dependence on the properties of the membrane hydrophobic core is not known. Here, we demonstrate that SecA:SecYEG-mediated protein transport is immensely stimulated by unsaturated fatty acids (UFAs). Furthermore, UFA-rich tetraoleoyl-cardiolipin, but not bis(palmitoyloleoyl)-cardiolipin, facilitate the translocation via the monomeric translocon. Biophysical analysis and molecular dynamics simulations show that UFAs determine the loosely packed membrane interface, where the N-terminal amphipathic helix of SecA docks. While UFAs do not affect the translocon folding, they promote SecA binding to the membrane, and the effect is enhanced manifold at elevated ionic strength. Tight SecA:lipid interactions convert into the augmented translocation. As bacterial cells actively change their membrane composition in response to their habitat, the modulation of SecA:SecYEG activity via the fatty acids may be crucial for protein secretion over a broad range of environmental conditions.

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.

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.

Relationship of alcohol production to lipid composition of yeast in a continuous flow bioreactor

1990 ◽  
Vol 68 (3) ◽  
pp. 661-668 ◽  
Author(s):  
G. H. Gil ◽  
W. J. Jones ◽  
T. G. Tornabene
Keyword(s):  
Fatty Acids ◽  
Lipid Composition ◽  
Continuous Flow ◽  
Unsaturated Fatty Acids ◽  
Ethanol Concentration ◽  
Immobilized Cells ◽  
Yeast Cells ◽  
Immobilized Cell ◽  
Alcohol Production ◽  
Respiratory Deficient

Saccharomyces cerevisiae was cultivated in a controlled aerated, dual-stage (column), continuous flow bioreactor in a hybrid free-cell and immobilized-cell state. The yeast cells maintained an ethanol concentration of 58–64 and 91–98 g/L in stages I and II, respectively. The lipid composition of the cells cultivated under these conditions was correlated to the effects of aeration by interrupting the aeration on days 113 and 266 of continuous operation. Under conditions of aeration or nonaeration, an alternating increase and decrease in the contents of squalene, sterols, and fatty acids of the respiratory-competent and -deficient unattached free cells was observed. The cellular free lipid compositions of the immobilized cells in the aerated and nonaerated conditions were similar and characteristic of respiratory-deficient cells with the exception of the immobilized cells exposed to a higher ethanol concentration (stage II). These cells contained a broader range of sterol components and increased levels of unsaturated fatty acids than immobilized cells at a lower ethanol concentration (stage I). The neutral lipid to phospholipid ratio decreased for respiratory-deficient cells with phosphatidylethanolamine and phosphatidylinositol being the principal phospholipids. The data demonstrated the essentiality of the hybrid bioreactor design for continuous long term performance and the importance of maintaining specific yeast lipid constituents for continuous high alcohol productivity.Key words: yeast immobilization, lipids, fatty acids, sterols, phospholipids, continuous flow, aeration, ethanol.

scholarly journals A role for unsaturated fatty acids in mitochondrial movement and inheritance.

1991 ◽  
Vol 115 (5) ◽  
pp. 1249-1257 ◽  
Author(s):  
L C Stewart ◽  
M P Yaffe
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Yeast Cells ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Prolonged Incubation ◽  
Mitochondrial Movement ◽  
Mitochondrial Transfer ◽  
Mitochondrial Distribution

Yeast cells with the mdm2 mutation display temperature-sensitive growth and defective intracellular mitochondrial movement at the non-permissive temperature. The latter phenotype includes both an absence of mitochondrial transfer into daughter buds of mitotically growing cells and an aberrant mitochondrial distribution in cells exposed to mating pheromone. The wild-type MDM2 gene was cloned by complementation, and DNA sequence analysis revealed a large open reading frame encoding a putative protein of 58.4 kD. The predicted protein sequence is identical to that reported for the yeast OLE1 gene encoding fatty acid desaturase. Unsaturated fatty acid levels are substantially decreased in mdm2 cells after a prolonged incubation at the non-permissive temperature. The addition of oleic acid complements the temperature-sensitive growth and mitochondrial distribution defects of the mutant cells. These results indicate that mdm2 is a temperature-sensitive allele of OLE1 and demonstrate an essential role for unsaturated fatty acids in mitochondrial movement and inheritance.

The origin of fatty acids in the hydrocarbon-utilizing microorganism Mycobacterium vaccae

1975 ◽  
Vol 21 (1) ◽  
pp. 85-89 ◽  
Author(s):  
D. H. King ◽  
J. J. Perry
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Pattern ◽  
Chain Elongation ◽  
Control Mechanisms ◽  
Long Chain Fatty Acids ◽  
Mycobacterium Vaccae ◽  
Cellular Lipids ◽  
Cellular Control

The fatty acid pattern in Mycobacterium vaccae strain JOB5 was examined after growth on n-alkanes (C14–C18), 1-alkenes (C14–C18), 2- or3-methyl octadecane, and 8-heptadecene. It was evident that monoterminal oxidation of n-alkanes was followed by β-oxidation and that both parent fatty acid and products of β-oxidation were incorporated into cellular lipids. Radioactive experiments demonstrated that there was desaturation of long-chain fatty acids. There was no evidence of chain elongation. Growth on 1-alkenes resulted in the incorporation of fatty acids that were products of two primary modes of oxidation: (1) methyl group attack resulting in ω-unsaturated fatty acids and (2) double-bond attack resulting in the removal of one carbon from the substrate. Cells of strain JOB5 grown on 2- and 3-methyl octadecane contained the corresponding iso- or anteiso-fatty acids in significant quantity. Cells cultured on 8-heptadecene contained 8- and 9-heptadecenoic acids, 6- and 7-pentadecenoic acids, 9- and 10-methyl hep-tadecanoic acids, and 7- and 8-methyl pentadecanoic acids. Fatty acid composition (C13 to C19) was affected by substrate chain length and was additionally modified by cellular control mechanisms.

scholarly journals Function of human mitochondrial 2,4-dienoyl-CoA reductase and rat monofunctional Δ3-Δ2-enoyl-CoA isomerase in β-oxidation of unsaturated fatty acids

1999 ◽  
Vol 344 (3) ◽  
pp. 903-914 ◽  
Author(s):  
Aner GURVITZ ◽  
Leila WABNEGGER ◽  
Ahmed I. YAGI ◽  
Maximilian BINDER ◽  
Andreas HARTIG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fatty Acids ◽  
Oleic Acid ◽  
Unsaturated Fatty Acids ◽  
Petroselinic Acid ◽  
Yeast Cells ◽  
C Terminus ◽  
Peroxisomal Targeting ◽  
Targeting Signals ◽  
Coa Reductase

Human 2,4-dienoyl-CoA reductase (2,4-reductase; DECR) and rat monofunctional ∆3-∆2-enoyl-CoA isomerase (rat 3,2-isomerase; ECI) are thought to be mitochondrial auxiliary enzymes involved in the β-oxidation of unsaturated fatty acids. However, their function during this process has not been demonstrated. Although they lack obvious peroxisomal targeting signals (PTSs), both proteins have been suggested previously to also occur in the mammalian peroxisomal compartment. The putative function and peroxisomal location of the two mammalian proteins can be examined in yeast, since β-oxidation of unsaturated fatty acids is a compartmentalized process in Saccharomyces cerevisiae requiring peroxisomal 2,4-dienoyl-CoA reductase (Sps19p) and peroxisomal 3,2-isomerase (Eci1p). A yeast sps19∆ mutant expressing human 2,4-reductase ending with the native C-terminus could not grow on petroselinic acid [cis-C18:1(6)] medium but could grow when the protein was extended with a PTS tripeptide, SKL (Ser-Lys-Leu). We therefore reason that the human protein is a physiological 2,4-reductase but that it is probably not peroxisomal. Rat 3,2-isomerase expressed in a yeast eci1∆ strain was able to re-establish growth on oleic acid [cis-C18:1(9)] medium irrespective of an SKL extension. Since we had shown that ∆2,4 double bonds could not be metabolized extra-peroxisomally to restore growth of the sps19∆ strain, we postulate that rat 3,2-isomerase acted on the ∆3 unsaturated metabolite of oleic acid by replacing the mutant's missing activity from within the peroxisomes. Immunoblotting of fractionated yeast cells expressing rat 3,2-isomerase in combination with electron microscopy supported our proposal that the protein functioned in peroxisomes. The results presented here shed new light on the function and location of human mitochondrial 2,4-reductase and rat monofunctional 3,2-isomerase.

scholarly journals Differences in Membrane Fluidity and Fatty Acid Composition between Phenotypic Variants of Streptococcus pneumoniae

2004 ◽  
Vol 186 (14) ◽  
pp. 4638-4644 ◽  
Author(s):  
Barak Aricha ◽  
Itzhak Fishov ◽  
Zvi Cohen ◽  
Noga Sikron ◽  
Stella Pesakhov ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Streptococcus Pneumoniae ◽  
Membrane Fluidity ◽  
Acid Composition ◽  
Rate Constant ◽  
Unsaturated Fatty Acids ◽  
Phase Variation ◽  
Bacterial Cells

ABSTRACT Phase variation in the colonial opacity of Streptococcus pneumoniae has been implicated as a factor in the pathogenesis of pneumococcal disease. This study examined the relationship between membrane characteristics and colony morphology in a few selected opaque-transparent couples of S. pneumoniae strains carrying different capsular types. Membrane fluidity was determined on the basis of intermolecular excimerization of pyrene and fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH). A significant decrease, 16 to 26% (P ≤ 0.05), in the excimerization rate constant of the opaque variants compared with that of the transparent variants was observed, indicating higher microviscosity of the membrane of bacterial cells in the opaque variants. Liposomes prepared from phospholipids of the opaque phenotype showed an even greater decrease, 27 to 38% (P ≤ 0.05), in the pyrene excimerization rate constant compared with that of liposomes prepared from phospholipids of bacteria with the transparent phenotype. These findings agree with the results obtained with DPH fluorescence anisotropy, which showed a 9 to 21% increase (P ≤ 0.001) in the opaque variants compared with the transparent variants. Membrane fatty acid composition, determined by gas chromatography, revealed that the two variants carry the same types of fatty acids but in different proportions. The trend of modification points to the presence of a lower degree of unsaturated fatty acids in the opaque variants compared with their transparent counterparts. The data presented here show a distinct correlation between phase variation and membrane fluidity in S. pneumoniae. The changes in membrane fluidity most probably stem from the observed differences in fatty acid composition.

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