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1.
The fatty acid composition of oyster larvae at various stages, as well as of the algal diet, were determined by gas liquid
chromatography (GC). Saturated fatty acids are the major fatty acid components in all larval stages and account for 34–62%,
30–35% and 35–81% of the neutral, polar and total lipids of algal-fed larvae respectively. Weight percentage of saturated
fatty acid in “starved” larvae was consistently higher (63–81%) during the whole period. The total polyunsaturated fatty acids
were higher in the polar lipids than in the neutral lipids. The concentration of the ω3 fatty acids also was comparatively
higher in the polar lipids than in the neutral lipids. In the total and neutral lipid fractions, the weight percentage of
polyunsaturated and ω3 fatty acids was higher in the eyed than in the pre-eyed (pediveliger) larvae. Eicosapentaenoic acid
(20∶5ω3) and 22∶6ω3 were not detected in lipids of “starved” and young larvae. There was an accumulation of 20∶5ω3, 22∶6ω3,
and total ω3 fatty acids in the older larvae. Lipid classes were separated by thin layer chromatography (TLC). There was no
qualitative change in lipid composition during larval development, but a marked increased of triacylglycerol in larvae up
to the stage of maturation in algae-fed larvae.
Contribution number 1195 of the Virginia Institute of Marine Science, Gloucester Point, VA 23062 相似文献
2.
The lipid composition of six thermophilic fungi (Myriococcum albomyces, Mucor miehei, Papulaspora thermophila, Rhizopus sp.,Thielavia thermophila (+)Thielavia thermophila (−), andTorula thermophila) was examined. The relative per cent total lipids (4.9–26.3%), neutral lipids (55.5–88.3%), polar lipids (11.7–44.6%) and
the fatty acid profile of each lipid fraction was determined. The predominant fatty acids were 16∶0, 18∶0 and 18∶2, and lesser
amounts of 12∶0, 14∶0, 15∶0, 16∶1, 16∶2, 17∶0 and 18∶3 were present. The total lipids contained an average of 0.96 double
bonds per mole fatty acid (unsaturation index [USI]) the neutral lipids 0.86 USI and the polar lipids 0.84 USI, excluding
the values forTorula thermophila. These data show a high degree of saturation and are consistent with data reported for other fungal thermophiles.Torula thermophila possessed abnormally high USI values (1.15–1.50) and was cultured at three different temperatures (25, 45 and 51 C). As the
culture temperature ofTorula thermophila increased, the USI decreased. The USI of the polar lipids ofTorula thermophila at 25, 45 and 51 C were 1.50, 1.28 and 1.11, respectively. Thus the membrane lipids of this fungus appear unusual for a thermophile. 相似文献
3.
Existence of a dietary maximal level or threshold for incorporation of ω3 fatty acids into membrane phospholipids is of interest
as it may further define understanding of the dietary requirement for ω3 fatty acids. To test whether feeding increasing levels
of dietary ω3 fatty acids continues to increase membrane ω3 fatty acid content, weanling rats were fed a nutritionally adequate
semipurified diet which provided increasing amounts of C20 and C22 ω3 fatty acids, such as 20∶5ω3 and 22∶6ω3. Dietary 20∶5ω3 and 22∶6ω3 were provided by substituting a purified shark oil concentrate
of high 22∶6ω3 content for safflower oil high in 18∶2ω6. After four weeks of feeding, nuclear envelopes from four animals
in each diet group were prepared, lipid was extracted and phospholipids separated. Arachidonic acid content in membrane phosphatidylcholine,
phosphatidylethanolamine, phosphatidylinositol and phosphatidylserine was significantly reduced by feeding increased dietary
levels of ω3 fatty acids. Decline of 20∶4ω6 level in phospholipid tended to stabilize when the dietary content of total ω3
fatty acids reached 4–5% of total fatty acids. Above this level, dietary ω3 fatty acids did not result in a further decrease
in membrane content of 20∶4nω6. Increase in membrane phospholipid content of 20∶5ω3 occurred as the dietary intake of ω3 fatty
acids increased from 1.1% to 5% of total fatty acids. A dietary ω3 fatty acid level of 2.2–3% was sufficient to result in
maximum incorporation of 22∶6ω3 into membrane phosphatidylcholine and phosphatidylethanolamine, but not into phosphatidylinositol
or phosphatidylserine. 相似文献
4.
Satyesh C. Pakrashi Pradeep K. Duffa Basudeb Achari Suniti Misra Amalesh Choudhury Subhashis Chattopadhyay Amitabha Ghosh 《Lipids》1989,24(5):443-447
Total lipids from hepatopancreas of the horseshoe crabs,Tachypleus gigas andCarcinoscorpius rotundicauda, obtained in 7.6 and 3.3% wet weight respective yields, were fractionated by various chromatographic techniques and identified
by gas-liquid chromatography and spectroscopic methods. Fatty acid-containing lipids were rich in 16∶0 (8.0–25%), 18∶1ω9 (6.9–22%)
and 18∶2ω6 (6.8–18.5%); appreciable amounts of 16∶1ω7, 18∶3ω3, 20∶5ω3 and 22∶6ω3 were also present. The level of 26∶0 in the
hydrocarbon fractions was unusually high (64 and 68%). Carbon chain lengths of major wax esters were 44, 46 and 48 forT. gigas and 38, 40 and 42 forC. rotundicauda. 1-O-Alkyl diglycerides were 7.2 and 9.1% of the total lipids in the two species and contained 14∶0(20%), 16∶0(60%) and 18∶0(20%)
alkyl chains along with a relatively higher percentage (32–35%) of saturated fatty acids. High levels of cholesterol (>50%
of total sterol) in the free and combined state were encountered in both samples, phospholipid contents being 40 and 35%,
respectively, and contained highest levels of unsaturated fatty acids. 相似文献
5.
Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal
sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/1H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols
in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C14 to C22. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol
were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing
30% of the total fatty acids. The alcohols of wax ester were all saturated with C20–C29 carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl
glycerol ethers. 相似文献
6.
R. A. Gibson 《Lipids》1983,18(11):743-752
The fatty acid methyl esters obtained by the esterification of total lipids extracted from 24 species of fin fish and 4 species
of invertebrates caught in the rivers and coastal waters of southern Australia were analyzed by gas chromatography. The lipids
of most species contained significant levels of arachidonic acid (0.7–15.8%) as well as the more common marine polyunsaturate,
eicosapentaenoic acid (0.7–15.9%). The major ω6 fatty acid present in most species was 20∶4; however, other fatty acids of
this series, including 18∶2, 22∶4 and 22∶5, were present. The level of total ω6 fatty acids ranged from 3.9 to 22.3% of the
total lipid. In general, the level of total ω3 polyunsaturates was higher than the total ω6 fatty acids with levels of ω3
fatty acids ranging from 9.6 to 48.2%. Only 2 fish (barramundi and gurnard perch) had ω6/ω3 ratios greater than 1.0. Most
of the Australian species examined contained low levels of fat (0.5–7.8% of fresh weight). Two species examined, callop (freshwater)
and blue groper (marine) contained sufficient quantities of both fat (7.7 and 7.8%) and arachidonic acid (4.8 and 9.3%) to
warrant consideration for commercial exploitation. 相似文献
7.
Analytical methods to obtain the detailed compositions of the fatty acids in oils containing more than one conjugated octadecatrienoic
acid by open-tubular gas liquid chromatography (GLC) and by reversed-phase high performance liquid chromatography (HPLC) were
established. Effective GLC separations ofcis,trans,trans-9,11,13-octadecatrienoic acid (ctt-9,11,13–18∶3),ctc-9,11,13–18∶3,ttc-9,11,13–18∶3,ttt-9,11,13–18∶3,ttc-8,10,12–18∶3, andttt-8,10,12–18∶3 were obtained with an opentubular column coated with the nonpolar liquid phase OV-1 using an instrument having
all-glass carrier gas pathways. The HPLC method also gave satisfactory separations for the isomeric conjugated octadecatrienoates
on the basis of number of thecis andtrans double bonds. Two or three minor conjugated trienoic acids were found along with the principal conjugated trienoic acid in
tung oil, and seed oils of cherry,Prunus sp., Momordica charantia, Trichosanthes anguina, Punica granatum, Catalpa ovata, andCalendula officinalis. The mechanism for the formation of the conjugated trienoic acid mixtures in the seed oils is discussed. TheC. ovata seed oil also containedct andtt-9,12-octadecadienoic acids. Thett isomer is presumed to be a precursor ofttc-9,11,13–18∶3, the main conjugated trienoic acid in this oil. 相似文献
8.
Tetraselmis suecica andDunaliella tertiolecta were grown for 24 hr in the presence of14C sodium bicarbonate and then fed separately to batches of juvenile oysters,Crassostrea gigas, for 3 days.D. tertiolecta contained fatty acids no longer than C18; 22∶6ω3 was absent inT. suecica. Analysis of the oyster fatty acids by radio gas chromatography (GC) showed that oysters were able to incorporate some of
the dietary14C label into long-chain fatty acids not supplied in the diet, e.g., C20 and C22 mono- and polyunsaturated fatty acids, and particularly 20∶5ω3. However, the low14C incorporation into fatty acids longer or more unsaturated than those supplied in the diet suggests that elongation and desaturation
activity in young oysters is not sufficient to sustain optimum growth. 相似文献
9.
Lipids of some thermophilic fungi 总被引:1,自引:0,他引:1
Total lipid content in the thermophilic fungi—Thermoascus aurantiacus, Humicola lanuginosa, Malbranchea pulchella var.sulfurea, andAbsidia ramosa—varied from 5.3 to 19.1% of mycelial dry weight. The neutral and polar lipid fractions accounted for 56.4 to 80.2% and 19.8
to 43.6%, respectively. All the fungi contained monoglycerides, diglycerides, triglycerides, free fatty acids, and sterols
in variable amounts. Sterol ester was detected only inA. ramosa. Phosphatide composition was: phosphatidyl choline (15.9–47%), phosphatidyl ethanolamine (23.4–67%), phosphatidyl serine
(9.3–17.6%), and phosphatidyl inositol (1.9–11.9%). Diphosphatidyl glycerol occurred in considerable quantity only inH. lanuginosa andM. pulchella var.sulfurea. Phosphatidic acid, detected as a minor component only inM. pulchella var.sulfurea andA. ramosa, does not appear to be a characteristic phosphatide of thermophilic fungi as suggested earlier. The 16∶0, 16∶1, 18∶0, 18∶1,
and 18∶2 acids were the main fatty acid components. In addition,A. ramosa contained 18∶3 acid. Total lipids contained an average of 0.93 double bonds per mole of fatty acids, and neutral lipids tend
to be more unsaturated than phospholipids. 相似文献
10.
The effectiveness of different fatty acids as inhibitors of fatty acyl Δ5 desaturation activity in human skin fibroblasts
has been investigated. When incubated with 2.25 μM [14C] eicosatrienoate (20∶3ω6) in otherwise lipid-free medium, these cells rapidly incorporate the radiolabeled fatty acid into
cellular glycerolipids and desaturate it to produce both [14C] arachidonate and [14C] docosatetraenoate. The Δ5 desaturation activity can be enhanced by prior growth of the cells without serum lipids. Elaidate
(9t–18∶1) is a potent inhibitor of Δ5 desaturation whiletrans-vaccenate (11t–18∶1) is virtually without effect. Oleate and linoleate are only mildly inhibitory. Linoelaidate (9t, 12t–18∶2)
is more inhibitory than linoleate but significantly less effective than elaidate. The effects of elaidate can be readily overcome
by increasing the concentration of exogenous eicosatrienoate. Studies with a variety oftrans monounsaturates of differing chain lengths indicate that the ω9trans fatty acids are potent inhibitors of Δ5 desaturation, while ω7trans fatty acids are relatively ineffective. Intact human fibroblasts could thus be important in characterizing novel fatty acids
as selective inhibitors of arachidonate synthesis in vivo. 相似文献
11.
Néstor M. Carballeira Anastacio Emiliano Anthony Sostre José A. Restituyo Ileana M. González Gretchen M. Colon Carmen G. Tosteson Thomas R. Tosteson 《Lipids》1998,33(6):627-632
The fatty acid composition of a Pseudomonas sp. (Alteromonas) and its host, the dinoflagellate Ostreopsis lenticularis, vectors in ciguatera fish poisoning, has been studied. The major fatty acids in O. lenticularis were 16∶0, 20∶5n-3, and 22∶6n-3, but 18∶2n-6, 18∶3n-3, and 18∶n-3 were also identified. In contrast to other dinoflagellates,
18∶5n-3 was not detected in O. lenticularis. Even-chain fatty acids such as 9–16∶1, 11–18∶1, and 13–20∶1 predominated in the Pseudomonas sp. from O. lenticularis, but 16–20% of (E)-11-methyl-12-octadecenoic acid was also identified. The chirality of the latter was confirmed by total synthesis (28% overall
yield) starting from oxacyclotridecan-2-one. The fatty acid compositions of two other Pseudomonas species, from the palytoxin-producing zoanthids Palythoa mamillosa and P. caribdea, were also studied and were similar to that of the Pseudomonas sp. from O. lenticularis. The possibility of using some of these fatty acids as chemotaxonomic lipids in identifying marine animals that consume toxic
dinoflagellates or zoanthids is discussed. 相似文献
12.
Platypus milk fat contains 98.5% triglyceride. Polyunsaturates (C18∶2–C22∶5) account for 29% of the triglyceride fatty acids
in the milk fat and 32% of the total fatty acids in the lipid of the food of the platypus. Linoleate and arachidonate are
the major ω6 polyunsaturates of both food and milk lipids. However, while the ω3 polyunsaturates linolenate and eicosapentaenoate
are present in both food and milk, docosapentaenoate is present in meaningful amounts in milk only. It is suggested that with
the exception of 22∶5ω3, the polyunsaturates in platypus milk originate in the diet. 相似文献
13.
Omega-3 fatty acids influence the function of the intestinal brush border membrane. For example, the omega-3 fatty acid eicosapentaenoic
acid (20∶5ω3) has an antiabsorptive effect on jejunal uptake of glucose. This study was undertaken to determine whether the
effect of feeding α-linolenic acid (18∶3ω3) or EPA plus docosahexaenoic acid (22∶6ω3) on intestinal absorption of nutrients
was influenced by the major source of dietary lipid, hydrogenated beef tallow or safflower oil. Thein vitro intestinal uptake of glucose, fatty acids and cholesterol was examined in rats fed isocaloric diets for 2 weeks: beef tallow,
beef tallow + linolenic acid, beef tallow + eicosapentaenoic acid/docosahexaenoic acid, safflower oil, safflower oil + linolenic
acid, or safflower oil + eicosapentaenic acid/docosahexaenoic acid. Eicosapentaenoic acid/docosahexaenoic acid reduced jejunal
uptake of 10 and 20 mM glucose only when fed with beef tallow, and not when fed with safflower oil. Linolenic acid had no
effect on glucose uptake, regardless of whether it was fed with beef tallow or safflower oil. The jejunal uptake a long-chain
fatty acids (18∶0, 18∶2ω6, 18∶3ω3, 20∶4ω6, 20∶5ω3 and 22∶6ω3) and cholesterol was lower in salfflower oil than with beef tallow.
When eicosapentaenoic acid/docosahexaenoic acid was given with beef tallow (but not with safflower oil), there was lower uptake
of 18∶0, 20∶5ω3 and cholesterol. The demonstration of the inhibitory effect of linolenic acid or eicosapentaenoic acid/docosahexaenoic
acid on cholesterol uptake required the feeding of a saturated fatty acid diet (beef tallow). These changes in uptake were
not explained by differences in the animals’ food intake, body weight gain or intestinal weight. Feeding safflower oil was
associated with an approximately 25% increase in the jejunal and ileal mucosal surface area, but this increase was prevented
by combining linolenic acid or eicosapentaenoic acid/docosahexaenoic acid with safflower oil. Different inhibitory patterns
were observed when mixtures of fatty acids were present together in the incubation medium, rather than in the diet: for example,
when 18∶0 was in the incubation medium with 20∶4ω6, the uptake of 20∶4ω6 was reduced, whereas the uptake was unaffected by
18∶2ω6 or 20∶5ω3. Thus, (1) the inhibitory effect of eicosapentaenoic acid/docosahexaenoic acid on jejunal uptake of glucose,
fatty acids and cholesterol was influenced by the major dietary lipid, saturated (beef tallow) or polyunsaturated fatty acid
(safflower oil); and (2) different omega-3 fatty acids (linolenic acid versus eicosapentaenoic acid/docosahexaenoic acid)
have a variable influence on the intestinal absorption of nutrients. 相似文献
14.
The carbon and energy source for aerobically grown cultures ofCandida guilliermondii profoundly influenced the neutral lipid content and the fatty acid composition of the individual lipid components. Methanol
(0.80%, w/v) grown cells cultivated at 30 C in presence of 0.025% ammonium sulfate contained 12% total lipids, 67% of which
was neutral lipids. Glucose (0.74%, w/v) or ethanol (0.53%, w/v) grown cells contained 21–22% total lipids, 80% of which was
neutral lipids, under the same conditions. Methanol-grown cells contained a decreased 18∶1 acid (52–54% of total fatty acids)
and an increased 18∶2 acid (23–25%), as compared with glucose- or ethanol-grown cells which contained 57–66% 18∶1 acid and
8–14% 18∶2 acid, in both neutral and polar lipid fractions. The relationship between methanol metabolism and desaturation
of fatty acid in yeast was discussed. 相似文献
15.
Thirteen-day old rats were given intracranial injections of 1-14C linolenic acid (allcis 9,12,15 octa decatrienoic acid) and were sacrificed after 8 hr. Analysis of brain fatty acids showed that 16∶0, 18∶0, 18∶1,
18∶3, 20∶3, 20∶4, 20∶5, 22∶5, and 22∶6 were labeled. The total fatty acid methyl esters were separated into classes according
to degree of unsaturation on a AgNO3∶SiO2 impregnated plate. The bands were scraped off and the eluted fatty acids were first analyzed by radiogas liquid chromatography
and then subjected to reductive ozonolysis to determine double bond position. The saturated acids, 16∶0, and 18∶0, as well
as the mono-unsaturated 18∶1, must have been formed from radioactive acetate produced by β oxidation of the injected linolenate.
Among the polyunsaturated fatty acids, the triene fraction was characterized and identified as 18∶3 ε3 (Δ9,12,15), the starting material, and 20∶3 ω3 (Δ11,14,17); the tetraene fraction was identified as 20∶4 ω3 (Δ8,11,14,17); the pentaene fraction was identified as 20∶5 ω3 (Δ5,8,11,14,17) and 22∶5 ω3 (Δ7,10,13,16,19); and, finally, the hexaene fraction was shown to be 22∶6 ω3 (Δ4,7,10,13,16,19). The biosynthesis of these ω3 family fatty acids in the brain in situ is discussed. 相似文献
16.
The phospholipid and phospholipid fatty acid composition of gill mitochondrial membranes from two temperate zone marine bivalve
mollusks, the quahog, Mercenaria mercenaria, and the American oyster, Crassostrea virginica, were examined after acclimation to 12 and −1°C. Cardiolipin (CL) was the only phospholipid with proportions altered upon
acclimation to −1°C, increasing 188% in the mitochondrial membranes of M. mercenaria. Although the ratio of bilayer stabilizing to destabilizing lipids is frequently associated with cold acclimation in ectothermic
species, no change was found in this ratio in either of the species. Polyunsaturated fatty acids (PUFA) were found only to
increase in C. virginica with cold acclimation, with total n-3 PUFA increasing in the phospholipid phosphatidylethanolamine, total n-6 PUFA increasing
in CL, and total PUFA increasing in phosphatidylinositol. Monounsaturated fatty acids, not PUFA, were found to have increased
in M. mercenaria, with 18:1n−9 increasing by 150% in CL, and 20∶1 increasing in both CL and phosphatidylcholine, by 146 and 192%, respectively.
These manipulations of membrane phospholipid and fatty acid composition may represent an attempt by these species to help
maintain membrane function at low temperatures. 相似文献
17.
The fatty acid composition of partially hydrogenated arachis (HAO), partially hydrogenated soybean (HSO) and partially hydrogenated
herring (HHO) oils and of a normal, refined arachis oil (AO) was studied in detail by means of direct gas liquid chromatography,
ultraviolet and infrared spectrophotometry and by thin layer chromatography fractionation on silver nitrate-silica gel plates
followed by gas liquid chromatography. It was shown that the partially hydrogenated oils all contained fatty acids withtrans double bonds. In the plant oils, thetrans acids were present mainly as elaidic acid. The HHO showed an almost equal distribution betweentrans 18∶1 ω9,trans 20∶1 ω>9 andtrans 22∶1 ω>9. Sometrans configuration was also found in the C20-and C22-dienes and trienes of the HHO. In all the oils, conjugated fatty acids were present in minor amounts only (<0.5%). Special
attention was given to the ω-acids known to be of specific nutritional value. The HSO contained about 32% linoleic acid, whereas
the content ofcis, trans+trans, cis andtrans, trans octadecadienoic isomers was 1.7% and 0.5%, respectively. The amount of linoleic acid in the HSO was even higher than that
of AO (29%). The HAO contained only 0.8% 18∶2 ω6 (linoleic acid). Further, two 18∶2 fatty acids with ω>6, acis, cis and atrans, trans isomer, were present in small amounts. The HHO contained 0.5% 18∶2 ω6 (linoleic acid). Isomers of 18∶2 ω>6 were also found
in the HHO. They may be hydrogenation products of higher unsaturated C18-acids orginally present. All the C20- and C22-dienes and trienes were shown to have an ω-chain greater than 6. Fatty acids with ω6-structure were not formed during partial
hydrogenation of the oils studied. 相似文献
18.
Effects of parenteral nutrition with high doses of linoleate on the developing human liver and brain
The developmental changes in the fatty acid composition of ethanolamine phosphoglycerides (EPG) and choline phosphoglycerides
(CPG) were studied in the liver and brain of 18 newborn infants with gestational ages ranging from 20 to 44 wk. A small group
of five newborns receiving total parenteral nutrition (TPN) with high doses of linoleic acid (18∶2ω6) was also studied and
compared to controls of the same gestational age to look for effects on the developmental fatty acid patterns of liver and
brain EPG and CPG. TPN with Intralipid 20% was given for 4–12 days, the total fat intake being 14.7–90 g (mean ±S.D.=47.1±29.8
g). The main developmental changes in the liver and brain of the control group were an increase in 22∶6ω3 (docosahexaenoic
acid) at the end of gestation and a linear decrease in 20∶4ω6 (arachidonic acid) and 18∶1ω9 (oleic acid) in EPG and CPG. A
very good correlation in the percent values of these fatty acids in the brain and liver tissues was obtained. Very significant
changes in the fatty acid composition of liver EPG and CPG could be found in the infants receiving TPN with Intralipidmainly
an increase in 18∶2ω6, a decrease in the linoleate elongation/desaturation to longer members of the series and a decrease
in the 22∶6ω3 levels of liver EPG and CPG. In the brain, only an increase in the 18∶2ω6 value of CPG, not accompanied by any
increase in the longer ω6 fatty acids, could be detected. Possible adverse effects of high doses of 18∶2ω6 on the tissue levels
of long chain polyunsaturated fatty acids (PUFA), especially of 22∶6ω3, are discussed. 相似文献
19.
We have previously reported that the relative content of 18∶3ω3 in adipose triglyceride (TG) of women was reduced following
major weight loss while on a very low calorie diet (VLCD). In an attempt to prevent this loss of 18∶3ω3 reserves, we have
tested two VLCD supplemented with varying amounts of 18∶3ω3. The formula (FORM) and food VLCD (2.1–3.0 MJ or 500–700 kcal/d)
contained 20 g/d of fat and provided the recommended dietary allowance for minerals and vitamins. FORM subjects (Group 1)
were 5 women [initial body mass index (BMI) of 36.8, 168% ideal body weight (IBW) who received 20 g/d of canola oil (1.6 g
18∶3ω3). Their mean weight loss was 23.9 kg in a 4–5 mon period. Food VLCD subjects (Group 2) were 6 women (BMI 33.9, 155%
IBW) supplemented with 2 g/d of linseed oil (1.1 g 18∶3ω3). Their mean weight loss was 17.4 kg in a 2–3 mon period. Needle
biopsies of adipose tissue were obtained from Group 1 before, at midpoint and after weight loss; and from Group 2 before and
after weight loss. The adipose TG and serum (Group 1) were separated and their fatty acid composition determined by thin-layer
and gas chromatography. In Group 1, adipose 18∶3ω3 fell from 0.65 to 0.59 wt%, then to 0.52 wt% during weight loss. In Group
2, it fell from 0.77 to 0.64 wt%. The fall in adipose 18∶3ω3 with weight loss was significant atP=0.01 (Group 1) andP<0.01 (Group 2). There were no differences between responses to the 1.1 g/d or 1.6 g/d 18∶3ω3 supplements. The relative content
of 18∶3ω3 in serum free fatty acids from Group 1 was reduced after major weight loss. Thus, in both groups the ω3 supplementation
did not help to maintain adipose tissue 18∶3ω3 during rapid weight loss, and its decrement may affect circulating lipid pools.
As adipose 18∶2ω6 did not change with weight loss, this reduction in the ratio of ω6 precursor to ω3 precursor could eventually
alter the balance of their products as well.
This work was presented in part at the North American Society for the Study of Obesity, Sacramento, California, 1991. 相似文献
20.
The activity of the overt form of rat liver mitochondrial carnitine palmitoyltrasferase or CPT0 (EC 2.3.1.21) towards different fatty acid substrates was studied. The following non-esterified fatty acids (NEFA) and their
CoA esters in the presence of 1% bovine serum albumin (BSA) were tested: 16∶0, 18∶0, 18∶1, 18∶2, 18∶3ω3, 20∶4, 20∶5ω3 and
22∶6ω3. The data fit a square hyperbolic model for enzyme catalysis (p<0.001, non-linear regression). Asymptotic Vmax and K0.5, substrate concentration at one-half Vmax, were calculated using total concentrations of acyl-CoA, or unbound concentrations of NEFA. BSA was found to act as a true
substrate reservoir for NEFA in that the dissociation of the NEFA-BSA complex was 10–330 times faster than the CPT0 reaction. Regardless of form (NEFA or CoA ester), 18∶3ω3 gave the highest, while 22∶6ω3 and 18∶0 gave the lowest rates of
acylcarnitine synthesis. Except for 18∶3ω3 and 18∶2, Vmax for NEFA was generally lower than for acyl-CoA, with the greates differences observed for 20∶4, 20∶5ω3 and 22∶6ω3, suggesting
that acyl-CoA synthesis may also be important in the control of the entry of these fatty acids into the mitochondria. The
data provide an enzymatic rationale for the relatively low content of 18∶3ω3 in esterified lipid. 相似文献