scholarly journals GENETIC ANALYSIS OF HYBRID STRAINS TRISOMIC FOR THE CHROMOSOME CONTAINING A FATTY ACID SYNTHETASE GENE COMPLEX (fas1) IN YEAST

Genetics ◽  
1973 ◽  
Vol 75 (3) ◽  
pp. 441-458
Author(s):  
Michael R Culbertson ◽  
Susan A Henry

ABSTRACT Evidence of spontaneous n+1 aneuploidy has been obtained by trisomic segregation analysis of four independently maintained stocks of Saccharomyces cerevisiae defective in saturated fatty acid synthesis (fas1). In all cases tested, only the chromosome bearing the mutant fatty acid locus was disomic. Tetrad analysis of trisomic hybrids enabled the identification of chromosome XI as the one bearing the fatty acid locus and the assignment of fragment 5 to chromosome XI. Statistical analysis of tetrad frequencies generated by markers in triplex configuration provided information on the meiotic configuration of pairing of the three homologous chromosomes. The possible relationship between defective nuclear membranes and the disjunction of chromosomes in fas1 strains is discussed.

1987 ◽  
Vol 241 (1) ◽  
pp. 189-192 ◽  
Author(s):  
I B Mogensen ◽  
H Schulenberg ◽  
H O Hansen ◽  
F Spener ◽  
J Knudsen

Bovine liver was shown to contain a hitherto undescribed medium-chain acyl-CoA-binding protein. The protein co-purifies with fatty-acid-binding proteins, but was, unlike these proteins, unable to bind fatty acids. The protein induced synthesis of medium-chain acyl-CoA esters on incubation with goat mammary-gland fatty acid synthetase. The possible function of the protein is discussed.


1983 ◽  
Vol 214 (2) ◽  
pp. 443-449 ◽  
Author(s):  
P Grimaldi ◽  
C Forest ◽  
P Poli ◽  
R Negrel ◽  
G Ailhaud

ob17 cells convert into adipose-like cells when maintained in the presence of physiological concentrations of insulin and tri-iodothyronine. After this conversion, insulin removal from differentiated ob17 cells gives within 24-48 h a large decrease in fatty acid synthetase, glycerol 3-phosphate dehydrogenase and acid:CoA ligase activities, as well as in the rate of fatty acid synthesis determined by [14C]acetate incorporation into lipids. All parameters are restored by insulin addition to initial values within 24-48 h. Dose-response curves of insulin on the restoration of glycerol 3-phosphate dehydrogenase activity and of fatty acid synthesis give half-maximally effective concentrations close to 1 nM, in agreement with the affinity for insulin of the insulin receptors previously characterized in these cells. Immunotitration experiments indicate that the changes in the specific activity of fatty acid synthetase are due to parallel changes in the cellular enzyme content. Therefore the ob17 cell line should be a useful model to study the long-term effects of insulin on the modulation of lipid synthesis in adipose cells.


1984 ◽  
Vol 52 (1) ◽  
pp. 131-137 ◽  
Author(s):  
G. R. Herzberg ◽  
Minda Rogerson

1. The effect of feeding casein, lactalbumin, soya-bean protein, gluten or gelatin on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1. 1. 1.49; G6PD), malic enzyme (EC 1. 1. 1.40; ME) ATP-citrate lyase (EC 4. 1. 3. 8; CL), acetyl CoA carboxylase (EC 6.4.1.2; ACCx) and glucokinase (EC 2. 7. 1. 2; GK) was examined in young growing rats.2. The total activities of ACCx, FAS, CL, GK, G6PD, GK, ME and fatty acid synthesis in vivo were positively correlated with protein quality.3. The specific activities of ACCx, FAS, CL, G6PD and fatty acid synthesis in vivo were positively correlated with protein quality.4. The specific activities of GK and ME were unrelated to protein quality.5. The results demonstrate a dissociation between ME and hepatic lipogenesis and suggest a role for the NADPH generated by ME which is not related to the needs of fatty acid synthesis.


1981 ◽  
Vol 45 (3) ◽  
pp. 529-538 ◽  
Author(s):  
G. R. Herzberg ◽  
Minda Rogerson

1. The effect of varying dietary levels of casein (40–140 g/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PD), malic enzyme (EC 1.1.1.40; ME), citrate cleavage enzyme (EC 4.1.3.8;CCE), acetyl CoA carboxylase (EC 6.4.1.2; AcCx), glucokinase (EC 2.7.1.2; GK), and pyruvate dehydrogenase (PDH) was examined in young, growing rats.2. The activities of AcCx, FAS, G6PD and in vivo fatty acid synthesis were generally found to increase with increased dietary protein.3. The levels of GK and PDH were not related to dietary protein.4. ME decreased with increasing dietary protein.5. The results demonstrate a dissociation between hepatic fatty acid synthesis and ME and suggest that when rats consume low-protein diets the NADPH needed for fatty acid synthesis is generated primarily by ME but that as the level of dietary protein is increased the contribution of ME is reduced while that of the phosphogluconate pathway becomes more important.


2010 ◽  
Vol 4 ◽  
pp. BBI.S4168 ◽  
Author(s):  
Sandeep J. Joseph ◽  
Kelly R. Robbins ◽  
Enrique Pavan ◽  
Scott L. Pratt ◽  
Susan K. Duckett ◽  
...  

Conjugated linoleic acids (CLA) are of important nutritional and health benefit to human. Food products of animal origin are their major dietary source and their concentration increases with high concentrate diets fed to animals. To examine the effects of diet supplementation on the expression of genes related to lipid metabolism, 28 Angus steers were fed either pasture only, pasture with soybean hulls and corn oil, pasture with corn grain, or high concentrate diet. At slaughter, samples of subcutaneous adipose tissue were collected, from which RNA was extracted. Relative abundance of gene expression was measured using Affymetrix GeneChip Bovine Genome array. An ANOVA model nested within gene was used to analyze the background adjusted, normalized average difference of probe-level intensities. To control experiment wise error, a false discovery rate of 0.01 was imposed on all contrasts. Expression of several genes involved in the synthesis of enzymes related to fatty acid metabolism and lipogenesis such as stearoyl-CoA desaturase (SCD), fatty acid synthetase (FASN), lipoprotein lipase (LPL), fatty-acyl elongase (LCE) along with several trancription factors and co-activators involved in lipogenesis were found to be differentially expressed. Confirmatory RT-qPCR was done to validate the microarray results, which showed satisfactory correspondence between the two platforms. Results show that changes in diet by increasing dietary energy intake by supplementing high concentrate diet have effects on the transcription of genes encoding enzymes involved in fat metabolism which in turn has effects on fatty acid content in the carcass tissue as well as carcass quality. Corn supplementation either as oil or grain appeared to significantly alter the expression of genes directly associated with fatty acid synthesis.


Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1428
Author(s):  
Marine Remize ◽  
Frédéric Planchon ◽  
Ai Ning Loh ◽  
Fabienne Le Grand ◽  
Christophe Lambert ◽  
...  

The synthetic pathways responsible for the production of the polyunsaturated fatty acids 22:6n-3 and 20:5n-3 were studied in the Dinophyte Alexandrium minutum. The purpose of this work was to follow the progressive incorporation of an isotopic label (13CO2) into 11 fatty acids to better understand the fatty acid synthesis pathways in A. minutum. The Dinophyte growth was monitored for 54 h using high-frequency sampling. A. minutum presented a growth in two phases. A lag phase was observed during the first 30 h of development and had been associated with the probable temporary encystment of Dinophyte cells. An exponential growth phase was then observed after t30. A. minutum rapidly incorporated 13C into 22:6n-3, which ended up being the most 13C-enriched polyunsaturated fatty acid (PUFA) in this experiment, with a higher 13C atomic enrichment than 18:4n-3, 18:5n-3, 20:5n-3, and 22:5n-3. Overall, the 13C atomic enrichment (AE) was inversely proportional to number of carbons in n-3 PUFA. C18 PUFAs, 18:4n-3, and 18:5n-3, were indeed among the least 13C-enriched FAs during this experiment. They were assumed to be produced by the n-3 PUFA pathway. However, they could not be further elongated or desaturated to produce n-3 C20-C22 PUFA, because the AEs of the n-3 C18 PUFAs were lower than those of the n-3 C20-C22 PUFAs. Thus, the especially high atomic enrichment of 22:6n-3 (55.8% and 54.9% in neutral lipids (NLs) and polar lipids (PLs), respectively) led us to hypothesize that this major PUFA was synthesized by an O2-independent Polyketide Synthase (PKS) pathway. Another parallel PKS, independent of the one leading to 22:6n-3, was also supposed to produce 20:5n-3. The inverse order of the 13C atomic enrichment for n-3 PUFAs was also suspected to be related to the possible β-oxidation of long-chain n-3 PUFAs occurring during A. minutum encystment.


1988 ◽  
Vol 251 (2) ◽  
pp. 547-551 ◽  
Author(s):  
J S Wilson ◽  
M A Korsten ◽  
L P Donnelly ◽  
P W Colley ◽  
J B Somer ◽  
...  

Administration of ethanol as part of a nutritionally adequate liquid diet to female Wistar rats was found to depress markedly incorporation of labelled glucose into adipose-tissue acylglycerol fatty acids. Similar results with labelled pyruvate and acetate suggested inhibition of the fatty-acid-synthesis pathway at, or distal to, the acetyl-CoA carboxylase step. Activities of acetyl-CoA carboxylase and fatty acid synthetase were markedly lower in ethanol-fed animals. The activity of another lipogenic enzyme, phosphatidate phosphohydrolase, was not affected by chronic ethanol feeding. These findings suggest that chronic ethanol administration has marked effects on adipose-tissue lipogenesis.


1980 ◽  
Vol 186 (1) ◽  
pp. 287-294 ◽  
Author(s):  
J K Hansen ◽  
J Knudsen

1. Purified cow mammary gland fatty acid synthetase synthesized long-chain unesterified and short-chain esterified fatty acids. 2. A direct relationship was observed between the amount of short-chain products synthesized and the concentration of acetyl-CoA in the incubation medium. 3. The short-chain products were identified as butyryl-CoA and hexanoyl-CoA. 4. Inhibition of the terminating thioester hydrolase of the fatty acid synthetase complex with phenylmethanesulphonyl fluoride did not inhibit the synthesis of short-chain products. 5. It is suggested that the synthesis of short-chain fatty acids involves the reverse of the ‘loading’ reaction.


1980 ◽  
Vol 43 (3) ◽  
pp. 571-579 ◽  
Author(s):  
G. R. Herzberg ◽  
N. Janmohamed

The effect of varying dietary levels of maize oil and tripalmitin (0–250 g fat/kg) on hepatic lipogenesis and the levels of hepatic fatty acid synthetase (FAS), glucose-6-phosphate dehydrogenase (EC 1.1.1.49; G6PD), malic enzyme (EC 1.1.1.38, 1.1.1.39, 1.1.1.40; ME) and glucokinase (EC 2.7.1.2; GK) was examined in meal-fed mice.2. Meal-fed mice compared to mice fed ad lib. show enhanced hepatic lipogenesis as demonstrated by an increased rate of in vivo fatty acid synthesis and increased levels of FAS, ME and G6PD. The level of GK in meal-fed mice was unchanged by meal feeding.3. Maize oil more effectively reduced in vivo hepatic lipogenesis than tripalmitin in meal-fed mice.4. Maize oil more effectively reduced the hepatic levels of FAS, G6PD, ME and GK than tripalmitin in meal-fed mice.5. The increased inhibition by maize oil is observed at all levels of fat in the diet investigated and has been shown not to be due to decreased carbohydrate intake nor to differences between the absorption of maize oil and tripalmitin.


1985 ◽  
Vol 226 (2) ◽  
pp. 551-556 ◽  
Author(s):  
K A Walker ◽  
J L Harwood

The synthesis of fatty acids de novo from [2-14C]malonyl-CoA was studied in fractions from lettuce (Lactuca sativa) and pea (Pisum sativum) chloroplasts. When lettuce chloroplasts were subjected to osmotic lysis, disintegration through a Yeda press and high-speed centrifugation, essentially all of the fatty-acid-synthetic activity was found to be soluble. The distribution of the activity in various chloroplast fractions was similar to that of soluble marker enzymes such as ribulose-1,5-bisphosphate carboxylase and NADP+-linked glyceraldehyde-3-phosphate dehydrogenase. Marked differences were apparent in the quality of products from fatty acid synthesis de novo in the various fractions of chloroplasts. Thus soluble fractions produced predominantly stearate, whereas those containing membranes produced a greater proportion of palmitate. In pea chloroplasts, osmotic lysis released almost all of the fatty acid synthetase into the stromal fraction. In this instance, no major alterations in the products of fatty acid synthesis were observed. The fatty-acid-synthetic activity of the stromal fraction was still soluble after prolonged ultracentrifugation. The results show clearly the soluble nature of fatty acid synthesis de novo in lettuce and pea chloroplasts. Thus fatty acid synthesis measured in microsomal fractions from such plant tissues is not due to the presence of chloroplastic membranes.


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