Yeast desaturases

2002 ◽  
Vol 30 (6) ◽  
pp. 1080-1082 ◽  
Author(s):  
C. E. Martin ◽  
C.-S. Oh ◽  
P. Kandasamy ◽  
R. Chellapa ◽  
M. Vemula
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Mrna Stability ◽  
Unsaturated Fatty Acids ◽  
Critical Role ◽  
Fatty Acid Desaturase ◽  
Proteolytic Processing ◽  
Low Oxygen ◽  
Response Element ◽  
Membrane Bound

The Saccharomyces OLE1 gene encodes the intrinsic membrane-bound Δ-9 fatty acid desaturase. OLE1 expression is regulated at the levels of transcription and mRNA stability by nutrient fatty acids and molecular oxygen. Its transcription is controlled through two distinct promoter elements, the fatty acid response element (FAR) region, and a downstream low-oxygen response element (LORE) that dramatically amplifies FAR-activated expression under hypoxic or cobalt-stimulated growth conditions. Transcription activation through both elements is repressed by unsaturated fatty acids. The half-life of the OLE1 mRNA is also dramatically reduced upon exposure to unsaturated fatty acids. OLE1 expression is governed by two homologous membrane-bound proteins, Spt23p and Mga2p, which activate OLE1 expression through N-terminal polypeptides that are released from the membrane through a ubiquitin-mediated mechanism that involves processing by the 23 S proteosome. Although proteolytic processing of Spt23p can be repressed by polyunsaturated fatty acids, Mga2p processing in normoxic cells appears to be regulated by a different mechanism. Mga2p is essential, however, for the induction of the high levels of expression that are triggered by hypoxia through the LORE promoter element. Surprisingly, Mga2p also plays a critical role in controlling OLE1 mRNA stability, suggesting that there may be a functional linkage between OLE1 transcription and the regulation of OLE1 mRNA stability.

scholarly journals Preparation and Characterization of PEGylated C18 Fatty Acids/Anti-SNAP25 Antibody-Targeted Liposomes

2019 ◽  
Vol 13 (2) ◽  
pp. 129-139
Author(s):  
Lai Ti Gew ◽  
Vicit Rizal Eh Suk ◽  
Misni Misran
Keyword(s):  
Fatty Acids ◽  
Particle Size ◽  
Fatty Acid ◽  
Zeta Potential ◽  
Unsaturated Fatty Acids ◽  
Membrane Surface ◽  
Good Choice ◽  
Head Group ◽  
Transmission Electron ◽  
Membrane Bound

Background: Unsaturated C18 fatty acids, such as oleic acid (L1), linoleic acid (L2), and linolenic acid (L3), are a good choice of lipids to prepare liposomes. They are inexpensive, biocompatible, nontoxic, and readily available compared with phospholipids. Moreover, cis-double bonds of unsaturated fatty acids prevent the packing of molecules which increases membrane fluidity in liposomes making them a good choice of starting materials to prepare liposomes. Objective: Unsaturated C18 fatty acid liposomes, as well as their PEGylated and non- PEGylated antibody-targeted liposomes, were prepared and characterized. Methods: The particle size and zeta potential of the prepared liposomes (1 mM, pH = 7.4) for 28 and 14 days, respectively, were monitored and characterized. Membrane-bound antibodies Anti-SNAP25 (AS25) and DOPE PEG2000 (DP) were conjugated to pure C18 fatty acid liposomes to achieve stable fatty acid formulations. Results: The mean particle sizes of pure L1, L2, and L3 liposome solutions were 125, 129, and 122 nm respectively, while their polydispersity index values were 0.28, 0.21, and 0.40 respectively. A large negative zeta potential value of 45 mV was observed due to anionic carboxylate head-group of pure liposomes. The incorporation of AS25 into L1/DP, L2/DP, and L3/DP liposome solutions stabilized their mean particle size and zeta potential measurements over 28 and 14 days, respectively. Conclusion: L1/DP/AS25 was found to be the most stable PEGylated antibody-targeted liposome system because its particle size remained between 90 and 125 nm in 28 days. Transmission electron microscopy observations also supported the incorporation of AS25 and DP on the membrane surface as predicted.

scholarly journals Single-cell Chromatin Accessibility and Lipid Profiling Reveals a Metabolic Shift in Adipocytes Induced by Bariatric Surgery

2021 ◽  
Author(s):  
Blaine Harlan ◽  
Hui Gyu Park ◽  
Roman Spektor ◽  
Bethany Cummings ◽  
J Thomas Brenna ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Weight Loss ◽  
Fatty Acid ◽  
Single Cell ◽  
Energy Homeostasis ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Desaturase ◽  
Chromatin Accessibility ◽  
Lipid Profiling ◽  
Beneficial Effects

Obesity promotes type 2 diabetes and cardiometabolic pathologies. Vertical sleeve gastrectomy (VSG) is used to treat obesity resulting in long-term weight loss and health improvements that precede weight loss; however, the mechanisms underlying the immediate benefits remain incompletely understood. Because adipose plays a crucial role in energy homeostasis and utilization, we hypothesized that VSG exerts its influences, in part, by modulating adipose functional states. We applied single-cell ATAC sequencing and lipid profiling to inguinal and epididymal adipose depots from mice that received sham surgery or VSG. We observed depot-specific cellular composition and chromatin accessibility patterns that were altered by VSG. Specifically, accessibility at Scd1, a fatty acid desaturase, was substantially reduced after VSG in mature adipocytes of inguinal but not epididymal depots. This was accompanied by reduced accumulation of SCD1-produced unsaturated fatty acids. Given these findings and reports that reductions in Scd1 attenuate obesity and insulin resistance and that unsaturated fatty acids stimulate glucose uptake, storage, and oxidation, our results suggest VSG exerts its beneficial effects through modifications of fatty acid profiles mediated by Scd1.

scholarly journals Molecular cloning of Δ9 fatty acid desaturase from the protozoan Tetrahymena thermophila and its mRNA expression during thermal membrane adaptation

1996 ◽  
Vol 317 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Shigeru NAKASHIMA ◽  
Yutong ZHAO ◽  
Yoshinori NOZAWA
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Cold Adaptation ◽  
Desaturase Activity ◽  
Unsaturated Fatty Acids ◽  
Self Regulation ◽  
Control Level ◽  
Fatty Acid Desaturase ◽  
Amblyomma Americanum ◽  
Transcriptional Level

In response to a decrease in its growth temperature, the protozoan Tetrahymena is known to increase the level of unsaturated fatty acids in its membrane phospholipids so as to maintain the correct physical state (fluidity) of the membranes. In this organism, synthesis of unsaturated fatty acids is initiated by Δ9 acyl-CoA desaturase. Our previous studies have shown that, during cold adaptation, the activity of microsomal palmitoyl- and stearoyl-CoA desaturase increases, reaching a maximal level at 2 h after a temperature down-shift to 15 °C. Two hypotheses have been proposed to explain this increase in desaturase activity: (1) self-regulation via a direct effect of reduced membrane fluidity, and (2) induction of desaturase mRNA. However, the precise mechanism is not clearly understood. In order to obtain further insight into the mechanism of regulation of the desaturase, we have isolated a gene that encodes Δ9 fatty acid desaturase from T. thermophila and examined its expression during cold adaptation. The nucleotide sequence indicates that the 1.4 kbp gene encodes a polypeptide of 292 amino acid residues which shows marked sequence similarity to Δ9 acyl-CoA desaturases from other sources, e.g. rat, mouse, Amblyomma americanum and Saccharomyces cerevisiae. This protein has three histidine-cluster motifs (one HXXXXH and two HXXHH), and two hydrophobic regions which are conserved among Δ9 acyl-CoA desaturases. The level of desaturase mRNA was sensitive to decreasing the temperature of the culture media, and was close to maximal immediately after the temperature was shifted down from 35 °C to 15 °C (0.8 °C/min). Thereafter, the amount of mRNA gradually decreased with time, but remained above the control level for at least 5 h. Furthermore, during the course of the cooling process to 15 °C, the increased expression of desaturase mRNA became evident at 27 °C. Nuclear run-on analysis and actinomycin D chase experiments revealed that the elevation of the mRNA level was due to increases in both transcription and mRNA stability. These results suggest that the enhanced desaturase activity is controlled, at least in part, at the transcriptional level.

scholarly journals Understanding and exploiting the fatty acid desaturation system in Rhodotorula toruloides

2020 ◽  
Author(s):  
Yanbin Liu ◽  
Chong Mei John Koh ◽  
Sihui Amy Yap ◽  
Lin Cai ◽  
Lianghui Ji
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linolenic Acid ◽  
Stress Resistance ◽  
Metabolic Flux ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Cell Mass ◽  
Fatty Acid Desaturase ◽  
Fatty Acid Production

Abstract Background Rhodotorula toruloides is a robust producer of triacylglycerol owing to its fast growth rate and strong metabolic flux under conditions of high cell density fermentation. However, the molecular basis of fatty acid biosynthesis, desaturation and regulation remain elusive.Results We present the molecular characterization of four fatty acid desaturase (FAD) genes in R. toruloides. Biosynthesis of oleic acid (OA) and palmitoleic acid (POA) was conferred by a single-copy ∆9 Fad (Ole1) as targeted deletion of which abolished the biosynthesis of all unsaturated fatty acids. Conversion of OA to linoleic acid (LA) and α-linolenic acid (ALA) was predominantly catalyzed by the bifunctional ∆12/∆15 Fad2. FAD4 was found to encode a trifunctional ∆9/∆12/∆15 FAD, playing important roles in lipid and biomass production as well as stress resistance. Furthermore, an abundantly transcribed OLE1-related gene, OLE2 encoding a 149-aa protein, was shown to regulate Ole1 regioselectivity. Like other fungi, the transcription of FAD genes was controlled by nitrogen levels and fatty acids in the medium. A conserved DNA motif, (T/C)(G/A)TTGCAGA(T/C)CCCAG, was demonstrated to mediate the transcription of OLE1 by POA/OA. The applications of these FAD genes were illustrated by engineering high level production of OA and g-linolenic acid (GLA). Conclusion Our work has gained novel insights on the transcriptional regulation of FAD genes, evolution of FAD enzymes and their roles in UFA biosynthesis, membrane stress resistance and, cell mass and total fatty acid production. Our findings should illuminate fatty acid metabolic engineering in R. toruloides and beyond.

A membrane-bound glycerol-3-phosphate acyltransferase from Thalassiosira pseudonana regulates acyl composition of glycerolipidsThis paper is one of a selection of papers published in a Special Issue from the National Research Council of Canada – Plant Biotechnology Institute.

Botany ◽  
2009 ◽  
Vol 87 (6) ◽  
pp. 544-551 ◽  
Author(s):  
Jingyu Xu ◽  
Zhifu Zheng ◽  
Jitao Zou
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Unsaturated Fatty Acids ◽  
Thalassiosira Pseudonana ◽  
Marine Diatom ◽  
Dihydroxyacetone Phosphate ◽  
Lipid Species ◽  
Membrane Bound

To what extent fatty acyltransferases control fatty acid composition in glycerolipids is largely unknown. To gain some insight into this process, we characterized a membrane-bound glycerol-3-phosphate acyltransferase (GPAT), designated TpGPAT, from the marine diatom Thalassiosira pseudonana Hasle & Heim. The glycerolipids from T. pseudonana consist predominantly of 16:0, 16:1ω7, and 20:5ω3 fatty acids. Heterologous expression of TpGPAT in a yeast GPAT-deficient mutant (gat1) demonstrated that TpGPAT could effectively use glycerol-3-phosphate, but not dihydroxyacetone phosphate, as fatty acyl acceptor. This enzyme highly preferred 16:0 in an in vitro enzyme assay, and discriminated against the monounsaturated 16-carbon fatty acid. Accordingly, expression of TpGPAT in gat1 resulted in approximately 18% and 12% increases of 16:0 in triacylglycerols and phospholipids, respectively. The unsaturated fatty acids, 16:1 and 18:1, on the other hand, were reduced by 15% and 21% in these two lipid species. Collectively, the results demonstrate that TpGPAT possesses a high substrate preference for 16:0-CoA and it exerts a large effect on the fatty-acid composition of glycerolipids.

scholarly journals Understanding and exploiting the fatty acid desaturation system in Rhodotorula toruloides

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yanbin Liu ◽  
Chong Mei John Koh ◽  
Sihui Amy Yap ◽  
Lin Cai ◽  
Lianghui Ji
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linolenic Acid ◽  
Stress Resistance ◽  
Metabolic Flux ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Biosynthesis ◽  
Cell Mass ◽  
Fatty Acid Desaturase ◽  
Fatty Acid Production

Abstract Background Rhodotorula toruloides is a robust producer of triacylglycerol owing to its fast growth rate and strong metabolic flux under conditions of high cell density fermentation. However, the molecular basis of fatty acid biosynthesis, desaturation and regulation remains elusive. Results We present the molecular characterization of four fatty acid desaturase (FAD) genes in R. toruloides. Biosynthesis of oleic acid (OA) and palmitoleic acid (POA) was conferred by a single-copy ∆9 Fad (Ole1) as targeted deletion of which abolished the biosynthesis of all unsaturated fatty acids. Conversion of OA to linoleic acid (LA) and α-linolenic acid (ALA) was predominantly catalyzed by the bifunctional ∆12/∆15 Fad2. FAD4 was found to encode a trifunctional ∆9/∆12/∆15 FAD, playing important roles in lipid and biomass production as well as stress resistance. Furthermore, an abundantly transcribed OLE1-related gene, OLE2 encoding a 149-aa protein, was shown to regulate Ole1 regioselectivity. Like other fungi, the transcription of FAD genes was controlled by nitrogen levels and fatty acids in the medium. A conserved DNA motif, (T/C)(G/A)TTGCAGA(T/C)CCCAG, was demonstrated to mediate the transcription of OLE1 by POA/OA. The applications of these FAD genes were illustrated by engineering high-level production of OA and γ-linolenic acid (GLA). Conclusion Our work has gained novel insights on the transcriptional regulation of FAD genes, evolution of FAD enzymes and their roles in UFA biosynthesis, membrane stress resistance and, cell mass and total fatty acid production. Our findings should illuminate fatty acid metabolic engineering in R. toruloides and beyond.

PECULIARITIES OF BLOOD FATTY ACID COMPOSITION OF FISHES DEPENDING ON SEASONAL CHANGES

2018 ◽  
pp. 124-131
Author(s):  
Vladimir Viktorovich Mungin ◽  
Ludmila Nikolaevna Loginova ◽  
Ekaterina Aleksandrovna Aryukova ◽  
Bibigul Mahabbatovna Kurkembaeva ◽  
Anna Aleksandrovna Bakhareva
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Seasonal Changes ◽  
Unsaturated Fatty Acids ◽  
Essential Fatty Acids ◽  
Critical Role ◽  
Omega 3 ◽  
Seasonal Aspect

Fats play a critical role in energy metabolism of fish. The bulk of the fatty acids of fish lipids are saturated with fatty acids and highly unsaturated acids with a predominance of 18 carbon atoms of mostly oleic acid, linoleic acid and their isomers. During oxidation they liberate two times more energy and, being a source of essential fatty acids, account for the complex basis of cell membranes. Efficiency of tissue permeability and its adaptation to different temperatures depend on lipids. The composition and ratio of fatty acids depend on a number of factors, including biological characteristics of the organism (age, species) and external environment influence (time of the year, temperature, water salinity). Fluctuations of fat content in one and the same individual during the year can be considerable and these fluctuations are repeated regularly. In addition, fats are related to the fish intake of fat-soluble physiologically active substances. The article presents the results of fatty acid composition of fish blood, depending on body mass and seasonal changes. Change levels of saturated and unsaturated fatty acids are shown in the seasonal aspect. Blood fatty-acid composition of carps in the lakes of the Republic of Mordovia is represented mostly by omega-3, -6, -9 fatty acids. It has been stated that if the number of fatty acid radicals increase or decrease, an organism adopts to the temperature changes, which helps to survive within the areal.

Molecular target analysis of stearoyl-CoA desaturase genes of protozoan parasites

2018 ◽  
Vol 63 (1) ◽  
pp. 48-54 ◽  
Author(s):  
He Lu ◽  
Xin Qin ◽  
Jing Zhang ◽  
Shuang Zhang ◽  
Yu Zhu ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Codon Usage ◽  
Unsaturated Fatty Acids ◽  
Fatty Acid Desaturase ◽  
Gc Content ◽  
Nucleotide Composition ◽  
Protozoan Parasites ◽  
Parasitic Protozoa ◽  
Stearoyl Coa Desaturase

AbstractProtozoan parasites can synthesize polyunsaturated fatty acids. They possess stearoyl-CoA desaturase to convert stearate into oleate and linoleate. Stearoyl-CoA desaturase are the key enzymes required for the synthesis of unsaturated fatty acids. It seems attractive to evaluate the possibility of using unsaturated fatty acid biosynthesis pathways as drug targets. In this study, the authors investigate codon usage bias, base composition variations and protein sequence in ten available complete stearoyl-CoA desaturase gene sequences fromToxoplasma gondii,Neospora caninumetc. The results show that fatty acid desaturase genes GC content high of parasitic protozoa genes, GC content up to 63.37%, while fatty acid desaturase genes of parasitic protozoa prefers to use codon ending with G/C. In addition, the expected curve was also drawn to reveal the relationship of ENC and GC3s when the codon usage was only subjected to the nucleotide composition constraint. The genes lied on the expected curve in ENC-plot, indicating nucleotide composition constraint played a role in the condon usage pattern. Protein analysis, we find that all proteins are stearoyl-CoA desaturase, have sites of iron-binding active centers and contain three conserved His-rich motifs. If stearoyl-CoA desaturase is unusual to these parasites, it provides basis as a promising target for the development of selective chemical intervention. Therefore, the Bioinformatics analysis of protein and codon can help improve the work of genetic engineering and drug screening.

scholarly journals Mga2p Processing by Hypoxia and Unsaturated Fatty Acids in Saccharomyces cerevisiae: Impact on LORE-Dependent Gene Expression

2002 ◽  
Vol 1 (3) ◽  
pp. 481-490 ◽  
Author(s):  
Yide Jiang ◽  
Michael J. Vasconcelles ◽  
Sharon Wretzel ◽  
Anne Light ◽  
Laura Gilooly ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Critical Role ◽  
Active Form ◽  
Dependent Manner ◽  
Low Oxygen ◽  
Mobility Shift ◽  
Hypoxic Induction ◽  
Hypoxic Conditions

ABSTRACT In Saccharomyces cerevisiae, OLE1 encodes a Δ9 fatty acid desaturase, an enzyme that plays a critical role in maintaining the correct ratio of saturated to monounsaturated fatty acids in the cell membrane. Previous studies have demonstrated that (i) OLE1 expression is repressed by unsaturated fatty acids (UFAs) and induced by low oxygen tension, (ii) a component of this regulation is mediated through the same low oxygen response element (LORE) in the OLE1 promoter, and (iii) Mga2p is involved in LORE-dependent hypoxic induction of OLE1. We now report that LORE-CYC1 basal promoter-lacZ fusion reporter assays demonstrate that UFAs repress the reporter expression under hypoxic conditions in a dose-dependent manner via LORE. Electrophoretic mobility shift assays show that UFAs repress the hypoxia-induced complex formation with LORE. Studies with a construct encoding a truncated form of Mga2p support the hypothesis that both hypoxia and UFA signals affect the processing of Mga2p and the UFA repression of OLE1 hypoxic induction is mediated through Mga2p. Data from Western blot assays provide evidence that under normoxic conditions, Mga2p processing produces approximately equimolar levels of the membrane-bound and processed forms and is unaffected by UFAs. Hypoxic induction of OLE1, however, is associated with increased processing of the protein, resulting in an approximately fivefold increase in the soluble active form that is counteracted by exposure of the cells to unsaturated fatty acids. Data from this study suggest that the Mga2p-LORE interaction plays an important role in OLE1 expression under both normoxic and hypoxic conditions.

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