Search results for "Unsaturated"

Revisiting delta-6 desaturase regulation by C18 unsaturated fatty acids, depending on the nutritional status.

2009

Dietary polyunsaturated fatty acids (PUFA) play a key role in regulating delta-6 desaturase (D6D), the key enzyme for long-chain PUFA biosynthesis. Nevertheless, the extent of their effects on this enzyme remains controversial and difficult to assess. It has been generally admitted that C18 unsaturated fatty acids (UFAs) regulate negatively delta-6 desaturase (D6D). This inhibition has been evidenced in regard to a high glucose/fat free (HG/FF) diet used in reference. However, several nutritional investigations did not evidence any inhibition of desaturases when feeding fatty acids. Because the choice of the basal diet appeared to be of primary importance in such experiments, our goal was t…

Unsaturated fatty acid bioconversion by apple pomace enzyme system. Factors influencing the production of aroma compounds

1996

Productions of volatile compounds (hexanal and 2,4-decadienal) obtained from polyunsaturated fatty acids by action of specific apple pomace enzyme system were quantitatively improved by increasing substrate and enzyme concentrations in the reaction medium. The importance of an exogenous supply of oxygen during bioconversion was also shown. Some physico-chemical factors involved in the pomace enzyme system expression were screened. A temperature of 25°C was favourable to the bioconversion. The control of alkaline or acidic conditions in the reaction medium may orientate the reaction preferentially to the production of one or other aldehyde.

Regulation of Farnesyl Diphosphate Synthase Gene Expression by Fatty Acids

2003

Cholesterol biosynthesis depends on the activity of regulatory enzymes, including the peroxisomal Farnesyl Diphosphate Synthase (FPPS ). Cholesterol regulates its own synthesis rate. Hence, as a response to cholesterol depletion, a feed back mechanism is activated, whereby sterol regulatory binding proteins (SREBPla, 1c and 2 ) are subjected to sequential proteolytic activation, which permits their interaction with specific DNA response elements from responsive genes. In turn, the transcriptional activity of cholesterol biosynthesis genes is induced. Conversely, cholesterol accumulation decreases SREBP maturation and transcription of controlled genes. In addition, polyunsaturated fatty acid…

Fatty acid composition of a cultured sturgeon hybrid (×)

2005

Abstract Analyses of fatty acids from the dorsal muscle of Acipenser naccarii  ×  A. baerii sturgeon hybrid were carried out. The data were compared with those reported in the literature for other sturgeons reared for human consumption. This hybrid would seem to be of great nutritional interest, its flesh being more beneficial for human health than those of other cultured sturgeons. In fact, the level of polyunsaturated fatty acids (PUFAs) was very high (34.7 ± 0.67%), being similar to that of monounsaturated fatty acids (37.9 ± 0.83%). Moreover, the PUFAs- n 3/PUFAs- n 6 ratio (6.74) was noticeably higher in this hybrid than in the other cultured sturgeon species. There were also high cont…

Production of 6-pentyl-?-pyrone byTrichoderma harzianum from 18?n fatty acid methyl esters

1992

Biosynthesis of 6-pentyl-α-pyrone byTrichoderma harzianum in two different media was evaluated. Best yields were found in nitrogen deficient medium (C/N=60). Limited growth seems to favour the production of this lactone. When fungal cells, precultured in low nitrogen medium, were incubated on methyl ricinoleate (10 g/l, C/N=60) an increase in 6-pentyl-α-pyrone production was observed in comparison with the media containing methyl oleate or methyl linoleate.

Apple pomace: An enzyme system for producing aroma compounds from polyunsaturated fatty acids

1991

This paper reports on the possibility of obtaining C-6 (hexanal) and C-10 (2,4-dedadienal) volatile aldehydes by degradation of linoleic acid (C18∶2 Δ 9–12) under the action of the intrinsic enzyme systems found in apple pomace. More aroma compounds are produced by micronization of the pomace and by adding SO2 (60 ppm) and vitamin C (500 ppm), thereby synergistically counteracting oxidation of phenolic compounds, which is a limiting factor in bioconversion.

Activation of liver x receptors promotes polyunsaturated fatty acid synthesis and eicosanoid secretion in human macrophages

2014

Mammalian Xenobiotic Epoxide Hydrolases

2002

Fatty acid composition of the seed lipids ofChamaerops humilisL. natural populations and its relation with the environment

2014

Seed lipids composition is a tool to discriminate among plant taxa and is related to phylogeny and biogeographic distribution. Aim of the present study was to evaluate the fatty acid (FA) composition of the seed lipids from nine natural Chamaerops humilis L. population and its relation with the climatic traits of the collection sites. The average seed lipids content was 54.8 g kg21 and the most represented FAs were oleic (478 g kg21 oil) and linoleic (230 g kg21 oil), with significant differences among the accessions. Most of the lipid traits significantly correlated with climatic traits. In particular, oleic acid negatively correlated with year potential evapotranspiration. These relations…

Cross-over study on effects of Mediterranean diet in two randomly selected population samples

2003

Abstract Two randomly selected population samples in Western Sicily, one rural (n = 40) and one urban (n = 40), were studied to evaluate the impact of dietary intervention on lipid, coagulative and fibrinolytic parameters. The two groups received the diets in a cross-over design with the following sequences: (a) baseline period; (b) 8-week dietary intervention period; (c) 8-week return to the original diet. During (a) and (c) all subjects consumed their usual diet. During the dietary intervention period (b), the rural sample consumed the urban sample's diet, while the urban sample consumed the rural sample's diet (the so-called “Mediterranean diet”). At baseline, after 8 weeks' dietary inte…