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1.
DeprivingSaccharomyces cerevisiae strain GL7 of exogenous unsaturated fatty acid supplements causes this sterol biosynthetic mutant to accumulate squalene
at the expense of squalene epoxide and squalene diepoxide. To further characterize the apparent relationship between squalene
epoxidase activity and membrane fatty acid composition, a variety of unsaturated fatty acids differing in their chain lengths
and in the positions and orientation (cis ortrans) of their double bonds were tested for their ability to promote turnover of endogenous squalene in cells previously deprived
of olefinic supplements. All of the unsaturated fatty acids tested were found to restore squalene epoxidase activity but there
were marked differences in their efficacies that best were correlated with the extent to which they reduced the medium chain
(C-10+C-12) saturated fatty acid content of cellular phospholipids. Additional studies demonstrated that de novo protein synthesis
was required for the restoration of squalene epoxidase activity in unsaturated fatty aciddeprived cells. 相似文献
2.
AVibrio species of bacterium known to contain the polyunsaturated fatty acid 20∶5n−3 was grown in both freshwater and seawater media
at 5 and 20°C and examined for adaptive changes in lipid composition. Phosphatidylethanolamine (PE) and phosphatidylglycerol
(PG), together with a smaller proportion of nonesterified fatty acids (NEFA), comprised almost all the lipid under all growth
conditions examined. Temperature had a more pronounced effect than the salinity of the medium on lipid composition. The proportion
of PE in total lipid was always higher at 5 than at 20°C. Conversely, the proportion of NEFA was lower at 5 than 20°C whereas
that of PG was not altered. The levels of saturated fatty acids in total lipid, PE and PG were all decreased by growth at
5°C. No differences were observed with respect to growth temperature in the levels ofcis 16∶1n−7, the principal monoenoic fatty acid in both PE and PG.Trans 16∶1n−7 was found to comprise 12.8–15.2% of fatty acids in PE and PG of bacteria grown at 5°C but only 4.4–8.5% of phospholipid
fatty acids in bacteria cultured at 20°C. Regardless of medium composition, a reduction in growth temperature from 20 to 5°C
also caused the proportions of 20∶5n−3 to increase from around 0.8 to 4.4% in PE and from around 4 to 20% in PG. The simultaneous
occurrence oftrans 16∶1n−7 and 20∶5n−3 is unique to thisVibrio species of bacterium. The increased proportions of both these fatty acids with decreasing temperature suggest that they have
a role in retailoring biomembrane phospholipids during temperature acclimation of the bacterium. 相似文献
3.
Francisella tularensis, LVS (live vaccine strain) grown in a chemically defined medium was found to have a lipid content of 21% by dry weight. The
two major phospholipids were identified as phosphatidylethanolamine (PE; 76%) and phosphatidylglycerol (PG; 24%) by thin layer
chromatographic analysis, staining characteristics and quantitative chemical analyses of fatty acid, phosphate and glycerol
constituents. PE contained a high proportion of 24∶0 fatty acid, with lesser amounts of 24∶1, 22∶0 and 10∶0. The major fatty
acids of PG were 18∶1 and 22∶0. Hydroxy fatty acids, which are prominent components ofF. tularensis, were conspicuously lacking in these phospholipids; it is therefore concluded that hydroxy fatty acids are constituents of
other structures of the organism. 相似文献
4.
Kazuo Watanabe Chikako Ishikawa Hitomi Inoue Deng Cenhua Kazunaga Yazawa Kiyosi Kondo 《Journal of the American Oil Chemists' Society》1994,71(3):325-330
Incorporation of exogenous docosahexaenoic acid (DHA) into bacterial phospholipids was examined as a method for DHA-linked
phospholipid production. The cultivation of 23 bacterial strains in medium with DHA showed that an eicosapentaenoic acid-producing
bacteriumShewanella sp. strain SCRC-2738 (strain SCRC-2738),Bacillus subtilis W23,B. cereus, an Antarctic marine bacterium strain S-7 (strain S-7), photosynthesis bacterium (PSB)Rhodopseudomonas capsulatus utilized for the production of larval marine fish,Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens andEscherichia coli K12 all incorporated DHA into their polar lipids. The polar lipids of the strain SCRC-2738, strain S-7, PSB andE. coli K12 were identified to be phospholipids. DHA was localized at thesn-2 position in the phospholipids of the four strains. Incorporation of exogenous DHA into their phospholipids produced an
increase in saturated fatty acids and a decrease in monounsaturated fatty acids exceptE. coli K12. The strain SCRC-2738 incorporated the largest amount of DHA into their phospholipids among the tested bacterial strains
in this study: DHA was 16% of the total fatty acids in the phosphatidylethanolamine (PE) and 29% in the phosphatidylglycerol
(PG). In the PSB, incorporated DHA was 12% of the total fatty acids in the PE, 10% in the PG and phosophatidylcholine so that
the PSB was nutritionally fortified. 相似文献
5.
This study examines the incorporation of highly unsaturated n−3 fatty acids (HUFA) into triacylglycerols (TAG) of brown adipose
tissue (BAT), and their effect on the positional distribution of saturated (SFA) and of unsaturated (UFA) 16- or 18-carbon
fatty acids. To this end, rats were fed a fish oil diet for up to four weeks. The stereospecific analysis of TAG was based
on generation ofsn-1,2- andsn-2,3-acylglycerols by Grignard degradation, followed by synthesis of phosphatidic acid and specific hydrolysis with phospholipase
A2. From the end of the first week of fish oil feeding, a steady-state in the fatty acid composition of TAG in BAT was reached.
HUFA concentration increased 30-fold, mainly at the expense of n−9 UFA and of SFA. The amount of SFA decreased selectively
at position 3, where these fatty acids were progressively replaced by n−3 HUFA. By contrast, the amount of UFA decreased at
all positions, and their positional distribution was not affected. About 60% of HUFA was incorporated at position 3. Nearly
twice as much 22∶6n−3 was incorporated into TAG than had been previously observed in white adipose tissue (WAT) [Leray, C.,
Raclot, T., and Groscolas, R. (1993)Lipids 28, 279–284]. At the steady-state, the distribution of HUFA was characterized by high proportions of 22∶6n−3 and 20∶5n−3 in
position 3. Moreover, in each position of TAG, a steady level was reached rapidly (within 1 wk). It is concluded that, during
fish-oil feeding, fatty acids in TAG of BAT show characteristic time-course changes that lead to a characteristic composition
and a tissue-specific positional distribution. This suggests that adipose tissue has its own specificity in controlling the
build-up of TAG stores, which is likely to be regulated by the specificity of acylating enzymes as well as molecular rearrangements. 相似文献
6.
Lipid peroxidation was induced in freshly isolated rat hepatocytes by incubation in the presence of Fe3+, resulting in accumulation of thiobarbituric acid reactive substances. Analysis of lipid classes revealed that the levels
and fatty acid compositions of the two major phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), remained
unchanged but the levels of triacylglycerols (TAG) were significantly reduced, and some of their polyunsaturated fatty acids
were selectively lost as the result of oxidant treatment. Acyl turnover in PC and PE as determined by 18O incorporation from H2
18O-containing media remained largely unchanged during oxidant treatment, while some increased turnover of the saturated fatty
acids in TAG was observed. We hypothesize that constitutive recycling of membrane phospholipids rather than selective in situ repair eliminates peroxidized species of PC and PE, TAG could serve as an expendable fatty acid reserve, providing a limited
but very dynamic pool of polyunsaturated fatty acids for the resynthesis of phospholipids. 相似文献
7.
The basidiomycetous mushroom Lentinula edodes (Shiitake) exhibits a unique process of cell differentiation termed “fruiting-body formation”. To clarify the relationship
between membrane lipids and fruiting-body formation in this fungus, we investigated variations in levels of phospholipids,
cerebrosides, fatty acyl residues in the major phospholipids, and fatty acyl and sphingoid base residues in cerebrosides during
vegetative growth and fruiting-body formation. PC, PE, and PS were the primary phospholipids in the cells of L. edodes. After a shift in growth temperature of L. edodes mycelia has been shifted from 25 to 18°C, the proportion of unsaturated FA (UFA), such as linoleic acid (18∶2) and oleic
acid (18∶1), increased. In contrast, during fruiting-body formation induced by the temperature downshift to 18°C, 18∶2 of
PC in the primordia and fruiting bodies decreased, and the UFA of PF and 18∶1 of PC increased compared with the proportions
in mycelia growing at 18°C. These results showed that the proportions of fatty acyl residues in PC and PE differed during
fruiting-body formation in L. edodes. Moreover, the amount of cerebrosides in primordia increased compared with those in mycelia and fruiting bodies and, in these
differentiating tissues, the proportion of 2-hydroxypentadecanoic acid increased whereas that of 2-hydroxyoctadecanoic acid
decreased compared with that in the mycelia. However, the proportion of sphingoid base residues in cerebrosides did not change
during fruiting-body formation in L. edodes. 相似文献
8.
Fibroblasts in culture and leukocytes have been widely used to study fatty acid and lipoprotein cellular metabolism. The present
investigations were designed to study the role of nutritional and environmental factors on lipid metabolism in these two types
of cells. Leukocytes freshly isolated from human blood and fibroblasts cultured in media enriched in human serum (HS) have
relatively similar fatty acid distributions. However, more important differences are observed in fibroblasts cultured in media
enriched with HS or with fetal bovine serum (FBS). It is obvious that the quantity and quality of fatty acids are very different
in FBS and HS, but intracellular regulation ensures relative homogeneity of saturated (SFA) and monounsaturated fatty acids
(MUFA) in the cells, particularly in phospholipids.
The first modifications induced by different media (FBS or HS) are detected on cellular growth; the differences seem to be
due more to the fatty acid (FA) quantitative supply than to the FA quality of each culture medium. The major modifications
in FA composition induced by different culture media concern the polyunsaturated fatty acids (PUFA) of phospholipids, especially
the n−6 family. The intracellular linoleic acid level depends on the level in the medium, but intracellular n−6 metabolite
levels depend both on the level in the medium and on the growth state of the cells. The n−3 family seems to be less affected
by the quality of the medium in our experiment, and the cells maintain a stable docosahexaenoic acid (22∶6n−3) level. A higher
content of the n−3 family in the medium induces a higher level of eicosa-or docosapentaenoic acid, rather than docosahexaenoic
acid itself.
Finally, the FA quality of the medium influences the cellular PUFA content but, with a low FA quantitative supply, the FA
quality of the medium has less influence on the cellular PUFA quality, and apparently has no effect on the SFA content of
phospholipids. Modification of the quantitative supply of the medium and of the quality of the cells (strain and growing state)
are more important for the distribution of SFA and MUFA in the neutral lipids of the cells. 相似文献
9.
Uptake and incorporation of long-chain fatty acids were studied in a human colorectal cancer cell line (HT29/219) grown in
culture medium supplemented with either fetal calf serum (FSC) or horse serum (HS). The cells were grown for 120 h with no
change of medium; the two major cellular lipid classes, the phospholipids and the triacylglycerols, were analyzed at regular
time-points. We observed significant changes in the concentration of most fatty acids throughout culture, and differences
in their composition when different sera were used to supplement the medium. Minimal levels of free fatty acids were found
in the cells, indicating a very small “free fatty acid pool”. A major difference between the cells grown in media supplemented
with different sera was the changes observed in concentrations of cellular polyunsaturated fatty acids during growth. In cells
grown with FCS (in which 20∶4n−6 is present), the levels of this acid in the phsopholipid and triacylglycerol fractions declined
rapidly during cell growth, suggesting further metabolism. In cells grown in medium supplemented with HS, 18∶2n−6 was the
major polyunsaturated acid present. There was clear evidence that this acid accumulated in the cellular triacylglycerol and
phospholipid fractions. Furthermore, its concentration did not decline during growth in culture, suggesting minimal conversion
to other polyunsaturated n−6 acids. Our results suggest that fatty acids from additional sources in the medium, for example
triacylglycerols and phospholipids associated with the lipoproteins, are taken up by the cells. There is also indication of
cellular fatty acid synthesis, particularly of monounsaturated and saturated acids during the culture period. HT29/219 cells
were shown to take up and incorporate radioactivity when trace amounts of [1-14C]-labeled arachidonic, linoleic or oleic acids were added to the culture medium. Most (80%) of the label was detected in
cellular phospholipids and triacylglycerols, although the specific activities of these various fatty acids were different
in the two lipid fractions. 相似文献
10.
Kotte Sagar Rao Pradosh Prasad Chakrabarti B. V. S. K. Rao R. B. N. Prasad 《Journal of the American Oil Chemists' Society》2009,86(2):197-200
Jatropha curcus L. oil has emerged as one of the most important raw materials for biodiesel production. However, no detailed study has been
reported on characterizing the lipid constituents of jatropha oil. The present study revealed that the total oil content of
jatropha seeds was 32% with a composition of 97.6% neutral lipids, 0.95% glycolipids and 1.45% phospholipids. The fatty acid
composition of total lipids, neutral lipids, phospholipids and glycolipids was also determined and found to contain oleic
acid (18:1) and linoleic acids (18:2) as major fatty acids. The phospholipids fraction was further characterized and quantified
and found to contain phosphatidyl choline (PC) 60.5%, phosphatidyl inositol (PI) 24% and phosphatidyl ethanolamine (PE) 15.5%.
The fatty acid composition and the positional distribution of the fatty acids of individual phospholipids were also reported. 相似文献
11.
Muhammad Younis Talpur Syed Tufail Hussain Sherazi Sarfaraz Ahmed Mahesar Saba Naz Huseyin Kara 《European Journal of Lipid Science and Technology》2012,114(2):222-228
The study was carried out to investigate the changes in saturated (SFA), monoene (MUFA), trans (TFA), and polyunsaturated (PUFA) fatty acids and the key fatty acid ratios (SFA/UFA, cis PUFA/SFA, C18:2/C16:0 and C18:3/C16:0) during potato chips frying in canola oil using single bounce attenuated total reflectance FTIR (SB‐ATR‐FTIR) spectroscopy. The data obtained from GC‐FID were used as reference. The calibration of main fat groups and their key fatty acid ratios were developed by partial least square (PLS) regression coefficients using 4000 to 650 cm?1 spectral range. FTIR PLS regression for the predicted SFA, MUFA, TFA, and PUFA were found 0.999, 0.998, 0.998, and 0.999, respectively, whereas for SFA/UFA, cis PUFA/SFA, C18:2/C16:0 and C18:3/C16:0 the regression coefficients were 0.991, 0.997, 0.996, and 0.994, respectively. We conclude that FTIR‐PLS could be used for rapid and accurate assessment of changes in the main fat groups and their key fatty acid ratios ratio during the frying process. Practical applications: FTIR‐ATR method is very simple, rapid, and environmentally friendly. No sample preparation is required and one drop of oil is enough for FTIR analysis. The proposed method could be applied for quick determination of key fatty acid ratios in the food processing industry. 相似文献
12.
C. Patrick Burns Diana G. Luttenegger Shiao-Ping L. Wei Arthur A. Spector 《Lipids》1977,12(9):747-752
We have compared the effect of diets containing 16% sunflower seed oil (polyunsaturated fat-rich) or 16% coconut oil (saturated
fat-rich) fed for 3–7 weeks on the composition of L1210 murine leukemia cells which were transplanted into the peritoneal
cavity during the final week of feeding. The L1210 phospholipids of mice fed the sunflower oil diet contained 43% polyenoic
fatty acids and an average of 1.5 double bonds per fatty acid molecule as compared to only 25% polyenoic fatty acids and 1.2
double bonds in the coconut oil group. In contrast, the cells from the sunflower oil group contained only 13% monoenoic fatty
acids as compared to 33% in those from the coconut oil group. When compared to phospholipids of tumors from mice who were
fed a commercial mouse chow, cells grown on sunflower oil had an 18% increase in polyenoic fatty acids and those grown on
coconut oil a 31% decrease. The greatest changes occurred in the proportion of oleate and linoleate. There was only a small
difference in the percentage of saturated fatty acids and in the mean fatty acid chain length among the tumor cells from animals
on the experimental diets. The changes in the fatty acid composition of the L1210 cell neutral lipids and the lipids of the
ascites fluid were similar to those observed in the phospholipids. A majority of the changes had occurred after 5 weeks of
feeding the special diet. These results indicated that the fatty acid saturation of tumor cell phospholipids can be altered
appreciably. The changes in fatty acid composition were not associated with any change in the sterol/phospholipid ratio of
the cells. Therefore, our results suggest that it may be possible to alter the physical properties and function of a tumor
cell membrane by dietary modification of its phospholipid composition. 相似文献
13.
Gudrún V. Skúladóttir Sigrún Gudmundsdóttir Gunnlaugur B. Ólafsson Stefán B. Sigurdsson Nikulás Sigfússon Jóhann Axelsson 《Lipids》1995,30(7):649-655
Levels of serum lipids and lipoproteins, and the fatty acid composition of plasma phospholipids, were measured in two genetically
comparable, but widely separated, populations. The 1975 mortality rates for ischemic heart disease were significantly higher
in one of these populations, the Manitoban residents of pure Icelandic descent, than in the other, a rural population from
Northeastern Iceland. Two study populations, Icelanders and Icelandic-Canadians, were drawn from these larger populations.
The study populations were matched for age and sex and divided into three age groups, 20–39, 40–59, and 60–69 years. In comparison
to the Icelandic-Canadians, the Icelanders exhibited significantly higher levels of total cholesterol, low-density lipoprotein
cholesterol, and high-density lipoprotein cholesterol, but lower triglyceride levels. Their plasma phospholipids contained
significantly lower levels of saturated fatty acids (SFA), monounsaturated fatty acids, and n−6 polyunsaturated fatty acids
(PUFA); but their n−3 PUFA levels were three times as high. It was additionally found that fatty acid composition of plasma
phospholipids differed among Icelanders of different ages. SFA levels were significantly lower, and n−6 PUFA levels significantly
higher, in the 20–39 year group than in the 60–69 year group, possibly due to different dietary fat consumption patterns between
generations. No corresponding age-related difference in the fatty acid composition of plasma phospholipids was found in the
Icelandic-Canadian study population. As the Icelandic and Icelandic-Canadian groups are assumed to be genetically similar,
the biochemical differences between them are evidently due to environmental, probably dietary, differences. The findings indicate
that n−3 PUFA may be cardioprotective in the context of an otherwise atherogenic diet. 相似文献
14.
The composition of liver phospholipids was studied in rats fed for 4 weeks diets containing 0, 100 or 300 mg 13-cis retinoic acid per kg diet. There was a significant decrease in phosphatidylcholine content, whereas the levels of phosphatidylethanolamine were slightly increased in liver phospholipids of rats fed 13-cis retinoic acid. The fatty acid composition of total phospholipids, PC, PE, and PI+PS fractions revealed a general increase in the levels of 18∶2 and 20∶3ω6, whereas the levels of 20∶4ω6 and C22 fatty acids were reduced in most of the hepatic phospholipids isolated from rats fed 13-cis retinoic acid containing diets. A decrease in the double-bond index of fatty acids was also observed in phospholipids of rats fed 13-cis retinoic acid. The data suggest that high levels of 13-cis retinoic acid may possibly be influencing the activities of microsomal desaturating and chain-elongating enzymes in the liver. 相似文献
15.
Minimal deviation hepatoma cells were cultured in a modified Swim's 77 medium supplemented with decreasing amounts of serum,
lipid-free serum, and lipid-free serum containing added palmitic or linoleic acids. Cellular phospholipids were extracted
and the class distribution determined quantitatively. The fatty acid composition of each phospholipid class was determined,
and the percentages from cells grown on each of the various media were compared. Cellular phospholipid class and fatty acid
compositions differed from media compositions, indicating that intact serum phospholipids are not incorporated into cellular
structures. Phosphatidylcholine percentages decreased as the media serum and lipid levels decreased, while phosphatidylinositol
and phosphatidylethanolamine percentages increased. Sphingomyelin of cells grown in medium containing added linoleic acids
contained a high level of a 24∶2 acid. All classes, except sphingomyelin, contained elevated levels of 18∶1 acid and decreased
levels of polyunsaturated fatty acids, relative to normal rat liver. Cells cultured on lipid-free medium did not contain increased
concentrations of 20∶3 acid, suggesting that this hepatoma cell cannot desaturate monoenoic acids. Phosphoglycerides of cells,
grown on lipid-free medium, had the highest monoene fatty acid concentration, whereas those cells grown on media containing
added linoleic acid had the lowest concentrations, suggesting that linoleate may inhibit or regulate monoenoic acid biosynthesis
in this cell. These mass data also demonstrate that monoenoic fatty acid biosynthesis in this cultured hepatoma cell responds
to dietary changes. 相似文献
16.
Docosahexaenoic acid (DHA, 22∶6n-3) and arachidonic acid (AA, 20∶4n-6) serve important roles in perinatal visual and neural
development. A neonatal pig model was used to determine if dietary supplementation with DHA and AA at slightly greater concentrations
than normally found in human milk would influence fatty acid accretion in retina. One-day-old piglets were assigned to one
of four diets (n=5/group): (i) STD, standard diet containing fat similar to infant formula; (ii) STD+DHA, 0.7% of fatty acids
as DHA; (iii) STD+AA, 0.9% as AA; and (iv) STD+BOTH, 0.8% as DHA plus 1.0% as AA. After 25 d, fatty acids in retina phosphatidylcholine
(PC) and phosphatidylethanolamine (PE) were determined. Supplementation with DHA resulted in approximately twofold increases
(P<0.05) in PC-DHA (4.88% in STD vs. 10.03% in STD+DHA and 9.47% in STD+BOTH). Similarly, AA supplementation increased PC-AA
1.3–1.4-fold (4.47% in STD vs. 6.19% in STD+AA and 5.70% in STD+BOTH). For PE, supplementation with either fatty acid or in
combination resulted in no significant increases, except for a 1.2-fold increase in DHA for STD+BOTH (32.66%) vs. STD (28.38%).
Thus, PC responded to dietary supplementation, with addition of DHA, AA, or BOTH, resulting in increases in respective fatty
acids; PE was less responsive, with only STD+BOTH resulting in increased DHA. No significant competition between DHA and AA
in incorporation into phospholipids was observed. In conclusion, consumption of a combination of DHA and AA by neonatal pigs
supported accretion of DHA in retina phospholipids, while simultaneously supplying the AA necessary for membrane phospholipids
and eicosanoid biosynthesis.
Based on a presentation at the AOCS Annual Meeting & Expo in San Antonio, Texas, May 7–11, 1995. 相似文献
17.
S. P. J. Namal Senanayake Fereidoon Shahidi 《Journal of the American Oil Chemists' Society》2000,77(1):55-61
The changes in composition of total and neutral lipids (NL) as well as glycolipids (GL) and phospholipids (PL) of borage (Borago officinalis L.) seeds, germinated in the dark at 25°C for 10 d, were studied. Total lipids constituted 34.0% of the dry matter of borage seeds. During germination, the content
of total lipids was decreased by 95%. NL accounted for 95.7% of total lipids prior to germination and were composed of triacylglycerols
(TAG; 99.1%), diacylglycerols (DAG; 0.06%), monoacylglycerols (MAG;0.02%), free fatty acids (FFA;0.91%), and sterols (0.02%).
The content of TAG was significantly (P≤0.05) decreased, while that of other components, such as MAG and FFA, significantly (P≤0.05) increased during germination. However, the content of DAG did not change. GL and PL accounted for 2.0 and 2.3% of total
lipids, respectively, and their contents significantly (P≤0.05) increased as germination proceeded. The thin layer chromatography-flame-ionization detection studies showed that phosphatidylcholine
(PC; 69.7%) was the major PL present. The total content of phosphatidylserine (PS) and phosphatidylethanolamine (PE), which
were coeluted, was 18.2%; phosphatidic acid (PA) was present at 11.2% of the total PL fraction. Lysophosphatidylcholine was
detected at 0.9%. The proportion of PC, PS, and PE significantly (P≤0.05) decreased during germination, but that of PA increased (P≤0.05) markedly. The fatty acid composition of lipid fractions changed as germination proceeded. The predominant fatty acids
of total lipids, NL, and GL were linoleic and linolenic acids, while those of PL were linoleic and palmitic acids. The present
study demonstrated that the overall changes of lipids seen in borage seeds during germination agree well with results for
other oilseeds. Changes in lipid compositions during germination result from the formation of tissues and metabolic interconversion
of lipid classes. Rapid changes in lipid composition during seed germination may enhance the nutritional value of the sprouts. 相似文献
18.
Total lipids of packed erythrocytes from healthy men 22 to 25 years old were extracted with chloroform-methanol mixture. Phospholipid
classes were separated from neutral lipids and pigments on a silicic acid column. Phosphatidyl inositol (PI) was freed of
its contaminants phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS) on an aluminum oxide column. Additional silicic
acid columns with modified solvent systems were needed for complete separation of other overlapped phospholipid classes. The
identification of phospholipids in each eluted fraction was accomplished by TLC, using the appropriate spray tests and reference
compounds, and confirmed on each of the isolated phospholipids by IR spectrophotometry.
The total content of phospholipids as determined by phosphorus analysis was found to be 2.63 mg/ml of packed cells. These
phospholipids were found to have the following composition (in per cent of total phospholipid): PI, 2.3; PE, 13.4; ethanolamine
plasmalogen (EP), 14.5; PS, 3.9; lecithin (L), 34.2; choline plasmalogen (CP), 1.4; sphingomyelin (Sph), 28.4 and lysolecithin
(LL), 1.7. The fatty acid composition of each phospholipid was determined by GLC. The average number of double bonds per fatty
acid in the isolated phospholipids was found to be as follows: PI, 1.5; PE, 1.9; EP, 3.6; PS, 2.1; L, 1.0; CP, 2.0; Sph, 0.2
and LL, 0.5. The positional distribution of fatty acids in both L and PE was ascertained by selective enzymatic hydrolysis
with phospholipase A. Saturated fatty acids of L were esterified predominantly in the α′-position, whereas in PE only 63.9
mole per cent of the saturated fatty acids were found in this position.
Presented in part at the AOCS Meeting in Los Angeles, April 1966.
Dept. of Health, Education and Welfare, USPHS. 相似文献
19.
Helen L. Ngo Alberto Nuñez Wenbin Lin Thomas A. Foglia 《European Journal of Lipid Science and Technology》2007,109(3):214-224
Branched‐chain (bc) saturated fatty acids (SFA) have potential as oleochemical intermediates since they have better oxidative stability than linear unsaturated fatty acids (UFA) and have better low‐temperature properties than linear SFA. Previous studies in converting UFA to bc‐FA using clay catalysts have resulted in only modest yields and conversions. Recent reports, however, have suggested that certain zeolites can be effective catalysts for converting UFA to bc‐FA in higher yields and conversions. In this work, we examined the scope and potential of the zeolite‐catalyzed synthesis of bc‐FA starting from readily available monounsaturated linear FA. Our results show that common UFA such as oleic acid can be converted to bc‐isomers using modified Ferrierite zeolite catalysts with high conversions (98%) and high selectivity (85%) and that the zeolite catalysts are reusable for at least three cycles. The positions of branching (methyl) on the FA chain were determined from the GC‐MS spectra of the picolinyl esters of the bc‐FA. 相似文献
20.
The fatty acid composition of the erythrocyte phospholipids was studied in samples from five high potassium (HK) and five
low potassium (LK) sheep. The total fatty acid composition, including the composition from the individual phospholipids in
the erythrocytes of these animals is reported. There were no significant differences between either the total fatty acid composition
or that of the individual phospholipids in the HK or LK cells. Sheep red cells had very little polyunsaturated fatty acids
in their phospholipids. Palmitic, stearic and oleic acids were the major components of glyceryl phospholipids, while nervonic
acid accounted for 50% of the fatty acids in the sphingomyelin fraction. The similarity between the fatty acid composition
of HK and LK red cells indicates that quantitative differences in the lipids of the membrane are not the primary reason for
the observed differences in the cation levels in the two types of cells. This agrees with conclusions drawn from previous
studies. 相似文献