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 Fatty acid desaturation and microsomal lipid fatty acid composition in experimental hypothyroidism

1982 ◽  
Vol 207 (1) ◽  
pp. 29-35 ◽  
Author(s):  
F H Faas ◽  
W J Carter
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Desaturase Activity ◽  
Unsaturated Fatty Acids ◽  
Lipid Fatty Acid ◽  
Rate Controlling Step ◽  
Delta 6 Desaturase ◽  
Lipid Fatty Acid Composition

We have studied the influence of experimental hypothyroidism in the rat on the synthesis of unsaturated fatty acids and on liver microsomal lipid fatty acid composition. Hypothyroid rats demonstrated an 80% decrease in delta 9 (stearate) desaturation and a 43% decrease in delta 6 (linoleate) desaturation. Liver microsomal fatty acid composition was altered in the hypothyroid animals with a significantly decreased proportion of arachidonate and increased proportions of linoleate, eicosa-8,11,14-trienoate, eicosapentaenoate and docosahexaenoate. The bulk of these changes occurred in both of the two major phospholipid components, phosphatidylcholine and phosphatidylethanolamine. All of the changes were corrected by treatment of the hypothyroid rat with 25 micrograms of tri-iodothyronine/100 g body wt. twice daily. The diminished delta 9 desaturation did not lead to any changes in fatty acid composition. The increased linoleate and decreased arachidonate levels may be due to the diminished delta 6 desaturase activity, the rate-controlling step in the conversion of linoleate into arachidonate. The increases in the proportions of the other polyunsaturated fatty acid components cannot be explained by changes in the synthesis of unsaturated fatty acids, but are probably due to diminished utilization of these fatty acids.

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 Cytochrome b 5 Coexpression Increases Tetrahymena thermophila Δ6 Fatty Acid Desaturase Activity in Saccharomyces cerevisiae

2013 ◽  
Vol 12 (6) ◽  
pp. 923-931 ◽  
Author(s):  
Jeremy L. Dahmen ◽  
Rebecca Olsen ◽  
Deirdre Fahy ◽  
James G. Wallis ◽  
John Browse
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Protein Interactions ◽  
Desaturase Activity ◽  
Tetrahymena Thermophila ◽  
Fatty Acid Desaturase ◽  
Vital Role ◽  
Content Type ◽  
Split Ubiquitin

ABSTRACT Very-long-chain polyunsaturated fatty acids such as arachidonic, eicosapentaenoic, and docosahexaenoic acids, are important to the physiology of many microorganisms and metazoans and are vital to human development and health. The production of these and related fatty acids depends on Δ6 desaturases, the final components of an electron transfer chain that introduces double bonds into 18-carbon fatty acid chains. When a Δ6 desaturase identified from the ciliated protist Tetrahymena thermophila was expressed in Saccharomyces cerevisiae cultures supplemented with the 18:2 Δ9,12 substrate, only 4% of the incorporated substrate was desaturated. Cytochrome b 5 protein sequences identified from the genome of T. thermophila included one sequence with two conserved cytochrome b 5 domains. Desaturation by the Δ6 enzyme increased as much as 10-fold when T. thermophila cytochrome b 5 s were coexpressed with the desaturase. Coexpression of a cytochrome b 5 from Arabidopsis thaliana with the Δ6 enzyme also increased desaturation. A split ubiquitin growth assay indicated that the strength of interaction between cytochrome b 5 proteins and the desaturase plays a vital role in fatty acid desaturase activity, illustrating the importance of protein-protein interactions in this enzyme activity.

scholarly journals The Effect of an Infant Formula Supplemented with AA and DHA on Fatty Acid Levels of Infants with Different FADS Genotypes: The COGNIS Study

Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 602 ◽  
Author(s):  
Isabel Salas Lorenzo ◽  
Aida Chisaguano Tonato ◽  
Andrea de la Garza Puentes ◽  
Ana Nieto ◽  
Florian Herrmann ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Breast Milk ◽  
Infant Formula ◽  
Early Life ◽  
Desaturase Activity ◽  
Reference Group ◽  
Fatty Acid Desaturase ◽  
Breastfed Infants ◽  
Major Allele

Polymorphisms in the fatty acid desaturase (FADS) genes influence the arachidonic (AA) and docosahexaenoic (DHA) acid concentrations (crucial in early life). Infants with specific genotypes may require different amounts of these fatty acids (FAs) to maintain an adequate status. The aim of this study was to determine the effect of an infant formula supplemented with AA and DHA on FAs of infants with different FADS genotypes. In total, 176 infants from the COGNIS study were randomly allocated to the Standard Formula (SF; n = 61) or the Experimental Formula (EF; n = 70) group, the latter supplemented with AA and DHA. Breastfed infants were added as a reference group (BF; n = 45). FAs and FADS polymorphisms were analyzed from cheek cells collected at 3 months of age. FADS minor allele carriership in formula fed infants, especially those supplemented, was associated with a declined desaturase activity and lower AA and DHA levels. Breastfed infants were not affected, possibly to the high content of AA and DHA in breast milk. The supplementation increased AA and DHA levels, but mostly in major allele carriers. In conclusion, infant FADS genotype could contribute to narrow the gap of AA and DHA concentrations between breastfed and formula fed infants.

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.

ω-3 Long-Chain Polyunsaturated Fatty Acids and Fatty Acid Desaturase Activity Ratios as Eventual Endophenotypes for ADHD

2012 ◽  
Vol 19 (11) ◽  
pp. 977-986 ◽  
Author(s):  
Marcela Henríquez-Henríquez ◽  
Sandra Solari ◽  
Gisela Várgas ◽  
Luis Vásquez ◽  
Fidel Allende ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Desaturase Activity ◽  
Fatty Acid Desaturase ◽  
Activity Ratios ◽  
Long Chain

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.

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.

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.

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