Évolution de la teneur en lipides de Leptosphaeria typhae en fonction de sa croissance et de sa reproduction sexuée : activité de synthèse et étude des lipides neutres et polaires

1985 ◽  
Vol 63 (12) ◽  
pp. 2460-2467
Author(s):  
Gérard Vidal

When perithecia appear (on the 7th day of growth), the mycelial lipid content falls and the degree of fat insaturation increases; fatty acid synthetase activity greatly increases. Lipid turnover is therefore accelerated. Among neutral lipids, triglycerides constitute the largest pool and their proportion increases when perithecia appear. Free fatty acids also increase, confirming the lipid turnover's acceleration. Polar lipids especially disappear; the phosphatidylcholine/phosphatidylethanolamine ratio increases when the fungus ascosporulates.

1975 ◽  
Vol 146 (2) ◽  
pp. 425-437 ◽  
Author(s):  
P J Weaire ◽  
R G Kekwick

1. Plastid and mitochondrial preparations were obtained by density-gradient centrifugation of homogenates made by gentle disintergration of avocado fruit mesocarp and cauliflower bud tissue. 2. The mitochondrial preparations had respiratory activity but did not incorporate [1-14C]acetate into fatty acids. 3. The plastid preparations incorporated [1-14C]acetate into the range of fatty acids found in the parent tissue. No fatty acid synthetase activity could be detected in the 12000g supernatant of these homogenates. 4. Homogenates produced by rupture of the tissue in an Ato-Mix blender and plastid preparations disintegrated by ultrasonic treatment both had fatty acid synthetase activity which did not sediment at 105000g and which formed mainly [14-C]stearate from [2-14C]malonyl-CoA. 5. It is concluded that the plastids are the principal site of fatty acid biosynthesis in the tissues studied.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Lena Foseid ◽  
Hanne Devle ◽  
Yngve Stenstrøm ◽  
Carl Fredrik Naess-Andresen ◽  
Dag Ekeberg

A thorough analysis of the fatty acid profiles of stipe and blade from the kelp species Laminaria hyperborea is presented. Lipid extracts were fractionated into neutral lipids, free fatty acids, and polar lipids, prior to derivatization and GC-MS analysis. A total of 42 fatty acids were identified and quantified, including the n-3 fatty acids α-linolenic acid, stearidonic acid, and eicosapentaenoic acid. The fatty acid amounts are higher in blade than in stipe (7.42 mg/g dry weight and 2.57 mg/g dry weight, resp.). The highest amounts of n-3 fatty acids are found within the neutral lipid fractions with 590.6 ug/g dry weight and 100.9 ug/g dry weight for blade and stipe, respectively. The amounts of polyunsaturated fatty acids are 3.4 times higher in blade than stipe. The blade had the highest PUFA/SFA ratio compared to stipe (1.02 versus 0.76) and the lowest n-6/n-3 ratio (0.8 versus 3.5). This study highlights the compositional differences between the lipid fractions of stipe and blade from L. hyperborea. The amount of polyunsaturated fatty acids compared to saturated- and monounsaturated fatty acids is known to influence human health. In the pharmaceutical, food, and feed industries, this can be of importance for production of different health products.


1976 ◽  
Vol 22 (12) ◽  
pp. 1710-1715 ◽  
Author(s):  
Simon W. T. Law ◽  
David N. Burton

The life cycle of Achlya involves germination of spores to form coenocytic somatic hyphae, followed by differentiation of hyphal tips into sporangia. From germination to release of new spores occupies 27–30 h. Total lipid made up 10% of dry weight in ungerminated spores. After germination, total lipid fell to 6% of dry weight in 15 h, then rose to7.7% at the time of sporangium formation. Half of the initial loss of lipid took place within 2 h of germination. The ability of Achlya to incorporate [1-14C]acetate into lipid was maximal at the time of sporangium formation, and glycerides were the principal component of total lipid to become 14C-labelled at all stages of the life cycle. Fatty acid synthetase activity measured in cell-free extracts was low in spores and in actively elongating mycelium, but increased during differentiation to a level 15-fold greater than that in spores. Fatty acid oxidation, as estimated by the release of 14CO2 from 1-14C-labelled fatty acids, was also maximal at the time of sporangium formation.


OENO One ◽  
1980 ◽  
Vol 14 (3) ◽  
pp. 147
Author(s):  
J. J. Lavaud ◽  
Monique Cherrad

<p style="text-align: justify;">Cinq catégories de pépins de Cabernet Sauvignon ont été séparées à la véraison. Plus de 95 p. 100 des acides gras sont contenus dans les lipides neutres. La différence de composition en acides gras des lipides polaires montre que la localisation des pépins dans une seule loge ou dans deux loges séparées a pour conséquence une modification du fonctionnement des désaturases.</p><p style="text-align: justify;">+++</p><p style="text-align: justify;">Five categories of Cabernet Sauvignon seeds were separated at the beginning of ripening. The neutral lipids contain more than 95 per cent of the fatty acids. The difference in the fatty acid content of polar lipids shows that seeds localized in just one section or in two separate sections results in a modification of the « desaturase » functioning.</p>


1976 ◽  
Vol 158 (3) ◽  
pp. 593-601 ◽  
Author(s):  
P G Roughan ◽  
C R Slack ◽  
R Holland

Spinach chloroplasts, isolated by techniques yielding preparations with high O2- evolving activity, showed rates of light-dependent acetate incorporation into lipids 3-4 fold higher than any previously reported. Incorporation rates as high as 500 nmol of acetate/h per mg of chlorophyll were measured in buffered sorbitol solutions containing only NaHCO3 and [1-14C]acetate, and as high as 800 nmol/h per mg of chlorophyll when 0.13 mM-Triton X-100 was also included in the reaction media. The fatty acids synthesized were predominantly oleic (70-80% of the total fatty acid radioactivity) and palmitic (20-25%) with only minor amounts (1-5%) of linoleic acid. Linolenic acid synthesis was not detected in the system in vitro. Free fatty acids accounted for 70-90% of the radioactivity incorporated and the remainder was shared fairly evenly between 1,2-diacylglycerols and polar lipids. Oleic acid constituted 80-90% of the free fatty acids synthesized, but the diacylglycerols and polar lipids contained slightly more palmitic acid than oleic acid. Triton X-100 stimulated the synthesis of diacylglycerols 3-6 fold, but stimulated free fatty acid synthesis only 1-1.5-fold. Added glycerol 1-phosphate stimulated both the synthesis of diacylglycerols and palmitic acid relative to oleic acid, but did not increase acetate incorporation into total chloroplast lipids. CoA and ATP, when added separately, stimulated acetate incorporation into chloroplast lipids to variable extents and had no effect on the types of lipid synthesized, but when added together resulted in 34% of the incorporated acetate appearing in long-chain acyl-CoA. Pyruvate was a much less effective precursor of chloroplast fatty acids than was acetate.


1969 ◽  
Vol 52 (5) ◽  
pp. 904-910 ◽  
Author(s):  
Garnett Wood ◽  
Lane Hintz ◽  
Harold Salwin

Abstract Chemical changes that occur in the proteins, nucleotides, and lipids of fish tissue during storage at low temperatures were investigated. Homogenized tissue, prepared from fresh rock-fish (striped hass, Roccus species), was stored up to six days at temperatures from -10° to 4°C and then analyzed. At 0°C and below, the solubility of myofibrillar proteins decreased. There were also changes in polyacrylamide gel electrophoretic patterns of protein extracts. The total nucleotide content decreased rapidly at all temperatures. The lipids were extracted from each sample and separated into neutral lipids, phospholipids, and free fatty acids by column chromatography. The fatty acid composition of each fraction was determined by gas chromatography. In the fresh tissue, polyunsaturated acids occurred in greatest proportion in the free fatty acid and phospholipid fractions, whereas inono-unsaturated acids were inofe highly concentrated in the neutral lipids. The percentages of saturated acids were approximately the same in all fractions. During storage, there were considerably larger losses of individual acids from phospholipids than from neutral lipids. The polyunsaturated acids of the phospholipid fraction were affected most. Over 10% of these aeids were lost in six days at ice temperature, but only a small proportion of the losses was accounted for by increases in free fatty acids. Oxidative proo esses may account for the imbalance because the rate of oxidation, as measured by the thio-barbituric acid test, increased with storage temperature in the same manner as the rale at which unsaturated fatty acids were lost from the pliospliolipuls. Losses of polyunsaturated acids from the neutral lipids were much smaller, suggesting a selectively protective mechanism or environment in that fraction. The changes in the phospholipid fatty acids may provide the basis for useful objective tests of fish lecomposilion.


2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Alexander M. Wathne ◽  
Hanne Devle ◽  
Carl Fredrik Naess-Andresen ◽  
Dag Ekeberg

Fatty acid (FA) profiles of the species Tettigonia viridissima, Chorthippus biguttulus, and Chorthippus brunneus were determined and quantitated. Extracted lipids were derivatized into FA methyl esters (FAMEs) prior to analysis by GC-MS. A total of 37 different FAs were identified in T. viridissima, yielding a total FA content of 10.4 g/100 g of dry matter. The contents of saturated FAs, monounsaturated FAs, and polyunsaturated FAs were 31.1, 35.9, and 33.0%, respectively. Lipids from T. viridissima were also fractioned into neutral lipids, free fatty acids, and polar lipids by offline solid phase extraction. For C. brunneus and C. biguttulus, 33 FAs were identified, yielding a total FA content of 6.14 g/100 g of dry matter. SFAs, MUFAs, and PUFAs, respectively, constituted 32.7, 25.1, and 42.1% of the total FA content. The contents of MUFAs, PUFAs, n-3 FAs, and n-6 FAs of each species, and the n-6/n-3 ratio, were subsequently discussed.


2004 ◽  
Vol 10 (1) ◽  
pp. 29-34 ◽  
Author(s):  
P. Sans ◽  
M. J. Andrade ◽  
S. Ventanas ◽  
J. Ruiz

Chemical parameters involved in technological meat quality for dry cured processing of Gascon pigs were studied in longissimus dorsi (LD) and biceps femoris (BF) muscles. Muscles from Gascon pigs showed 2.60 and 2.84% of intramuscular fat content, 23.64 and 22.14% protein content and 1.34 and 4.63mg of myoglobin per gram of muscle (respectively LD and BF). Intramuscular fat (IMF) and myoglobin levels were higher than those reported for commercial pigs, but lower than those previously found in Iberian pigs. A similar situation was detected in the fatty acid composition of neutral and polar lipids of both muscles. Thus, monounsaturated fatty acids (MUFA) in neutral lipids of Gascon pig muscles (LD and BF respectively) were 58.27 and 51.98%, while polyunsaturated fatty acids (PUFA) levels were 5.61 and 14.13% respectively; values similar to those found in Iberian pigs and quite different to usual values in commercial pig breeds. The same trend was found in polar lipids. Both muscles showed a low susceptibility to induced lipid oxidation, in agreement with their fatty acid composition. These results pointed out that meat from pigs of the Gascon breed showed optimal characteristics for dry cured processing.


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