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1.
Minimal deviation hepatoma 7288C cells were cultured in a modified Swim's medium supplemented with decreasing levels of serum,
lipid-free serum, lipid-free serum plus fatty acids, and other additives. Cellular and media neutral lipid classes were quantitated,
the fatty acids of triglycerides and sterol esters analyzed, and the carbon number distribution of triglycerides determined.
Cellular triglyceride biosynthesis virtually was inhibited when the medium was supplemented with bovine serum alone. This
inhibition was not observed when the medium was supplemented with fetal calf serum alone or mixtures of fetal calf serum and
bovine serum. Cells cultivated on medium supplemented with lipid-free serum plus palmitic or linoleic acids had much lower
levels of free and esterified cholesterol. The fatty acid composition of cellular triglycerides and cholesterol esters differed
dramatically from the corresponding media lipid classes. Except when linoleic acid was added to the medium, changes in the
media serum and lipid levels had only marginal effects upon the fatty acid composition of cellular triglycerides and cholesterol
esters. These data, in conjunction with earlier data that showed the media neutral lipid levels did not decrease during cell
growth, indicate that these hepatoma cells utilize little or no serum triglycerides and cholesterol esters. Linoleic acid
added to the medium dramatically reduced the level of 18∶1 acids in cellular triglycerides and cholesterol esters. Palmitic
acid added to the medium did not change the fatty acid compositions significantly. Comparison of experimentally determined
and calculated triglyceride carbon number percentages indicated a random distribution of fatty acids in this glyceride. The
fatty acid composition of cellular triglycerides was similar to the composition of the cholesterol esters. The lack of characteristic
and distinguishable compositions of these two classes that occur in most normal tissues suggests a loss of specificity in
the lipid metabolism of this neoplasm at the class level. 相似文献
2.
Randall Wood 《Lipids》1973,8(12):690-701
Minimal deviation hepatoma cells were cultured as monolayers to confluency in roller flasks containing modified Swim's medium,
supplemented with decreasing amounts of serum, lipid-free serum, and lipid-free serum containing added fatty acids. Good cell
growth was observed until serum levels fell below 5% of the medium. Media containing lipid-free serum or lipid-free serum
plus linoleic or palmitic acids did not support good growth. Lipids were extracted from cells; media, obtained during the
first and last half of the incubation period, resolved into neutral and phospholipid fractions; fatty acid composition of
each fraction analyzed by gas liquid chromatography; and lipid class distributions compared by thin layer chromatography.
The data showed that the media contained more neutral lipids and phospholipids after incubation than initially, indicating
that minimal deviation hepatoma cells excreted lipids into the media. The class composition of the excreted lipids resembled
that of the serum. A comparison of media, cells, and serum fatty acid compositions indicated that the lipids secreted into
the media were of cellular origin. Although some differences were noted, in general, cells grown on the nine different media
had the same ca. neutral lipid and phospholipid class and fatty acid compositions. In contrast, dramatic differences were
observed in the class and fatty acid compositions of the serums from that of the cells and media. These results indicate that
exogenous serum lipids had little influence on cellular class and fatty acid compositions of the minimal deviation hepatoma
cells. This neoplasm did not contain detectable levels of glyceryl ether diesters, indicating that this compound is not characteristic
of all tumors. Lipid class profiles and fatty acid compositions of cells grown on various media suggest that the minimal deviation
hepatoma cells can synthesize most, if not all, neutral lipid and phosphoglyceride classes found in liver.
Presented at the AOCS Meeting, New Orleans, April 1973. 相似文献
3.
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
4.
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
5.
The lipid composition of Yoshida ascites hepatoma cells was analyzed together with that of ascitic plasma and of livers and
blood plasma from host and normal rats. In comparison to normal livers, host livers showed no significant differences in the
content of the various lipid classes, but contained a higher percentage of palmitic acid and a lower proportion of arachidonic
acid in the major phospholipid classes. In addition, tumor growth induced a marked hypertriglyceridemia in host animals; changes
in the concentration of other plasma lipid classes were not statistically significant. The ascitic plasma contained small
amounts of lipids mainly constituted by cholesteryl esters and phospholipids. Yoshida hepatoma cells contained less phospholipids
in comparison to both host and normal liver, while the increased level of triglycerides and the decrease of free fatty acids
were not statistically significant. Hepatoma cells showed appreciable amounts of ether-linked lipids associated in part to
neutral lipids (as glyceryl ether diesters) and, in part, to ethanolamine and choline phosphoglycerides. The alkyl groups
in GEDE as well as in ethanolamine and choline phosphoglycerides were mainly constituted by C16∶0 and C18∶0 followed by C18∶1. The alk-1-enyl groups in ethanolamine and choline phosphoglycerides were C16∶0 and C18∶0 with only a minor proportion of C18∶1. In comparison to both host and normal liver, Yoshida hepatoma cells showed significant changes in the fatty acid composition
of neutral lipids and phospholipids. Some of the major changes consisted of an increase of monoenoic acids associated with
a decrease of arachidonic and docosahexaenoic acids in phosphatidylethanolamine, phosphatidylcholine, and phosphatidylinositol. 相似文献
6.
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
7.
Fatty acids ofSterculia foetida were added to the medium used to maintain the Morris hepatoma 7288C in culture. The effect of this supplement on the lipid
composition was examined. Overall, monoene levels were decreased with 18∶1 levels reduced by 40%. Saturated fatty acid levels
were increased, with stearate (18∶0) levels 220% of control values. No effect occurred on the level of polyunsaturates (18∶2,
20∶4, 22∶5, 22∶6). These changes in fatty acid makeup were observed in both neutral and phospholipid fractions, and all lipid
classes were affected. Triglycerides were most affected with a 66% decrease in 18∶1. There appeared to be little specificity
of effect in the phospholipids with 18∶1 levels decreased 40–60% in all classes. All classes were therefore dependent on an
endogenous supply of 18∶1. Examination of the distribution of geometrical isomers of 18∶1 reveals that in all lipid classes,
except diphosphatidylglycerol (DPG), the ratio of Δ11 to Δ9 isomer decreased toward the isomeric distribution displayed by
total medium lipids. In DPG, although 18∶1 levels were lowered, the isomeric distribution increased. DPG, synthesized and
found in the mitochondria, may use a separate pool of 18∶1 during synthesis. Cyclopropene fatty acids (sterculic and malvalic)
were incorporated into both neutral and phospholipid fractions with preferential incorporation into triglycerides. Cyclopropene
fatty acids were not selectively incorporated into any phospholipid species. Sphingomyelin did not incorporate cyclopropene
fatty acids, indicating that a different class of acyltransferase is used in the formation of this phospholipid class. 相似文献
8.
Monoenoic acid fractions were isolated from phosphatidylcholines, phosphatidylethanolamines, triglycerides, and cholesterol
esters derived from minimal deviation hepatoma 7288C cells cultured on 11 media containing varying levels of serums and lipids.
Hexadecenoate (16∶1), octadecenoate (18∶1), and eicosenoate (20∶1) fractions were subjected to ozonolysis and the isomeric
composition of the monoene fractions determined quantitatively by gas liquid chromatography. The 16∶1 fractions consisted
of palmitoleic acid, the Δ9 isomer (85–90%), and the Δ11 isomer (10–15%) in most of the cases; growth media and lipid class
origin had little effect upon composition. The predominate acids of the 20∶1 fraction were the Δ13 and Δ11 isomers. Generally,
the Δ13 isomer was present in the highest concentration, and this isomer was higher in phosphatidylcholines than the other
classes. Vaccenic acid represented 33–66% of the 18∶1 fraction, and the balance was oleic acid. Oleic acid concentrations
decreased, and vaccenic acid levels increased as the growth medium serum and lipid levels decreased. Lipid classes did not
exhibit any distinct preference for either isomer. These data represent the first quantitative isomeric analysis of monoenoic
acids derived from individual lipid classes and are the first to show the occurrence of high levels of vaccenic acid in neoplastic
cells. This study suggests that the elevated levels of oleic acid, one of the most frequently observed changes in tumor lipids,
may, in fact, represent elevated levels of vaccenic acid. 相似文献
9.
Robert D. Lynch 《Lipids》1980,15(6):412-420
Cultures of human diploid cell strain IMR-90 were supplemented with γ-linolenic acid, 18∶3ω6, by constant infusion over 72
hr. Cell growth was twice that observed when the same amount of fatty acid was supplied as a single dose at the start of a
72-hr incubation. Using the infusion method, growth of cells receiving monoenoic or polyenoic fatty acids was compared. The
age of these cells in vitro was measured in terms of the culture mean population doubling level (PDL). Population doubling
level refers to the mean number of doublings elapsed since establishment of a primary culture. At PDL from 24–53, the growth
of cells from cultures supplemented with oleic acid was similar to that of noninfused cultures. Gamma linolenic acid, 18∶3ω6,
and to greater extent arachidonic acid, 20∶4ω6, however, caused suppression of cell multiplication at PDL≤32, but not at PDL≥44.
The polyunsaturated fatty acid (PUFA) levels in cell phospholipids were reduced by exogenous oleic acid to half that of nonsupplemented
cells at all PDL tested. Conversely, the PUFA levels in phospholipids were elevated by a factor of 1.6 at all PDL when cultures
were infused with 18∶3ω6. Triglyceride levels at the end of 72 hr were similar, but much higher than the controls, regardless
of the fatty acid supplied. Growth inhibition, modification of phospholipid acyl group content and triglyceride levels were
not appreciably affected when the amount of monoenoic or polyenoic fatty acid infused into the cultures was doubled. The elongation
of 18∶3, as well as the distribution of 18∶3 and its elongation products, between triglyceride and phospholipid, was dependent
on whether the 18∶3 was of the ω3 or ω6 family. 相似文献
10.
The effect of very low levels of dietary long-chain n−3 fatty acids on Δ6 desaturation of linoleic acid (18∶2n−6) and α-linolenic
acid (18∶3n−3), and on Δ5 desaturation of dihomo-γ-linolenic acid (20∶3n−6), in liver microsomes and its influence on tissue
fatty acids were examined in obese and lean Zucker rats and in Wistar rats. Animals fed for 12 wk a balanced diet containing
ca. 200 mg of long-chain polyunsaturated n−3 fatty acids per 100 g of diet were compared to those fed the same amount of α-linoleic
acid. Low amounts of long-chain n−3 fatty acids greatly inhibited Δ6 desaturation of 18∶2n−6 and Δ5 desaturation of 20∶3n−6,
while Δ6 desaturation of 18∶3n−3 was not inhibited in Zucker rats and was even stimulated in Wistar rats. Inhibition of the
biosynthesis of long-chain n−6 fatty acids was reflected in a decrease in arachidonic acid (20∶4n−6) content of serum lipids
when fasting, and also in the phospholipid fatty acids of liver microsomes. On the contrary, heart and kidney phospholipids
did not develop any decrease in 20∶4n−6 during fish oil ingestion. Docosahexaenoic acid (22∶6n−3), present in the dietary
fish oil, was increased in serum lipids and in liver microsome, heart, and kidney phospholipids. 相似文献
11.
The lipid concentration and fatty acid composition of the whole liver and of cultured hepatocytes isolated from the livers
of rats fed ad libitum (fed), fasted for 24 hr (fasted), or fasted for 48 hr and then refed a fat-free, high carbohydrate
diet for 48 hr (refed) was studied. Hepatocytes were maintained as monolayer cultures in serum-free, lipid-free media and
their fatty acid composition was analyzed at 3, 24, 48, 72 and 96 hr. The livers of fed animals, as well as their hepatocytes,
contained less total lipid than those from animals on either of the other dietary regimes. Livers of fasted animals had three
times the amount of lipid found in the livers of fed animals, and the livers of refed animals contained five times the amount
of lipid as the livers of fed animals (all based on mg lipid/g wet weight of liver). The fatty acid composition of hepatocytes
after 3 hr of culturing was very similar to that of fresh liver when compared in each of the dietary regimes. However, while
the fatty acid compositions of livers and hepatocytes from fed and fasted animals were similar, the pattern in liver of refed
animals was quite distinct from that of the fed animals. In the fed and fasted animals palmitic acid (16∶0), stearic acid
(18∶0), oleic acid (18∶1[n-9]), linoleic acid (18∶2[n-6]) and arachidonic acid (20∶4[n-6]) were the major fatty acids of the
liver; in refed animals 16∶0, palmitoleic acid (16∶1[n-7]), 18∶0, 18∶1(n-9) andcis-vaccenic acid (the n-7 isomer of oleic acid) were the major fatty acids. During maintenance in culture the 18∶1(n-9) content
of the hepatocytes increased in cells from livers of animals on all three dietary regimes. The polyunsaturated fatty acid
content was similar in fresh livers and isolated hepatocytes in all samples when compared on the basis of μg fatty acid/mg
of hepatocyte or liver protein. It was also found that the polyunsaturated fatty acid content of hepatocytes was remarkedly
stable with time of culture when the cells were incubated in serum-free, lipid-free medium. Thus, isolated hepatocytes maintained
in serum-free medium appear to be a possible system for the evaluation of the effects of prior nutritional status on fatty
acid metabolism in the whole animal, not subject to hormonal and other somatic influences which often complicate the interpretation
of such nutritional studies. 相似文献
12.
Functional and ultrastructural effects of essential fatty acid deficiency in kidney epithelial cells
Madin-Darby canine kidney (MDCK) epithelial cells were grown in culture medium supplemented with 1% fetal bovine serum (FBS)
to provide a cell culture model of essential fatty acid deficiency (EFAD). 5,8,11-Eicosatrienoic acid (20∶3n−9) accumulated
in cellular phospholipids, and arachidonic acid (20∶4) decreased. A large increase in cellular cholesterol/phospholipid ratio
was observed. Hemicyst formation was greatly reduced from normal levels in the EFAD-MDCK cells. Scanning and transmission
electron microscopy revealed that EFAD-MDCK were much flatter than their normal counterparts. They had much less dense surface
microvilli, mitochondria and other organelles were very sparse, except in the perinuclear area, and much of the peripheral
cytoplasm was amorphous. The EFAD was rapidly reversed by the addition of as little as 10 μM linoleic or arachidonic acid
to the medium. Cells supplemented with 10% FBS, the usual culture condition, displayed borderline EFAD, with intermediate
levels of 20∶3n−9 and 20∶4 and hemicyst formation. These studies suggest that EFAD reduces water and electrolyte transport
in renal tubular epithelium. 相似文献
13.
The influence of the linoleic acid levels of diets containing partially hydrogenated marine, oils (HMO) rich in isomeric 16∶1,
18∶1, 20∶1 and 22∶1 fatty acids on the fatty acid profiles of lipids from rat liver, heart and adipose tissue was examined.
Five groups of rats were fed diets containing 20 wt% fat−16% HMO+4% vegetable oils. In these diets, the linoleic acid contents
varied between 1.9% and 14.5% of the dietary fatty acids, whereas the contents oftrans fatty acids were 33% in all groups. A sixth group was fed a partially hydrogenated soybean oil (HSOY) diet containing 8%
linoleic acid plus 32%trans fatty acids, mainly 18∶1, and a seventh group, 20% palm oil (PALM), with 10% linoleic acid and notrans fatty acids.
As the level of linoleic acid in the HMO diets increased from 1.9% to 8.2%, the contents of (n−6) polyunsaturated fatty acids
(PUFA) in the phospholipids increased correspondingly. At this dietary level of linoleic acid, a plateau in (n−6) PUFA was
reached that was not affected by further increase in dietary 18∶2(n−6) up to 14.5%. Compared with the HSOY- or PALM-fed rats,
the plateau value of 20∶4(n−6) were considerably lower and the contents of 18∶2(n−6) higher in liver phosphatidylcholines
(PC) and heart PC. Heart phosphatidylethanolamines (PE) on the contrary, had elevated contents of 20∶4(n−6), but decreased
22∶5(n−6) compared with the PALM group.
All groups fed HMO had similar contents oftrans fatty acids, mainly 16∶1 and 18∶1, in their phospholipids, irrespective of the dietary 18∶2 levels, and these contents were
lower than in the HSOY group.
High levels of linoleic acid consistently found in triglycerides of liver, heart and adipose tissue of rats fed HMO indicated
that feeding HMO resulted in a reduction of the conversion of linoleic acid into long chain PUFA that could not be overcome
by increasing the dietary level of linoleic acid. 相似文献
14.
Randall Wood 《Lipids》1982,17(11):763-770
Groups of rats were fed a fat-free diet supplemented with 0.5% safflower oil (control) or the control diet containing 0.5%
of 5,8,11,14-eicosatetraynoic acid (TYA). Blood was collected weekly and plasma lipids analyzed. After 4 weeks, the animals
were killed and the liver lipids were analyzed in detail. The acetylenic fatty acid perturbed plasma neutral lipid and phospholipid
class concentrations and reduced growth rates. Liver triglyceride concentrations were reduced dramatically in the TYA fed
animals, suggesting interference with complex lipid synthesis. Plasma and liver triglycerides were shifted to higher molecular
weight species suggesting that TYA affected fatty acid metabolism. The phospholipids showed an accumulation of 18∶2 and a
fall in 20∶4 percentages indicating an inhibition in the conversion of linoleate to arachidonate. All major lipid classes
exhibited an increase in 18∶1 levels. Analysis of the octadecenoate positional isomers indicated the proportion of oleate
increased substantually in all lipid classes whereas vaccenate proportions had fallen dramatically. All of the data collectively
suggest that TYA inhibits the elongation of unsaturated fatty acids. A group of rats bearing hepatoma 7288CTC were also fed
the TYA diet. Host liver lipids were affected by TYA similar to normal TYA fed animals, but the effects on hepatoma lipids
were marginal. 相似文献
15.
Previous studies in our laboratory have shown that marine oils, with high levels of eicosapentaenoic (EPA, 20∶5n−3) and docosahexaenoic
acids (DHA, 22∶6n−3), inhibit the growth of CT-26, a murine colon carcinoma cell line, when implanted into the colons of male
BALB/c mice. Anin vitro model was developed to study the incorporation of polyunsaturated fatty acids (PUFA) into CT-26 cells in culture. PUFA-induced
changes in the phospholipid fatty acid composition and the affinity with which different fatty acids enter the various phospholipid
species and subspecies were examined. We found that supplementation of cultured CT-26 cells with either 50 μM linoleic acid
(LIN, 18∶2n−6), arachidonic acid (AA, 20∶4n−6), EPA, or DHA significantly alters the fatty acid composition of CT-26 cells.
Incorporation of these fatty acids resulted in decreased levels of monounsaturated fatty acids, while EPA and DHA also resulted
in lower levels of AA. While significant elongation of both AA and EPA occurred, LIN remained relatively unmodified. Incorporation
of radiolabeled fatty acids into different phospholipid species varied significantly. LIN was incorporated predominantly into
phosphatidylcholine and had a much lower affinity for the ethanolamine phospholipids. DHA had a higher affinity for plasmenylethanolamine
(1-O-alk-1′-enyl-2-acyl-sn-glycero-3-phosphoethanolamine) than the other fatty acids, while EPA had the highest affinity for phosphatidylethanol-amine
(1,2-diacyl-sn-glycero-3-phosphoethanolamine). These results demonstrate that,in vitro, significant differences are seen between the various PUFA in CT-26 cells with respect to metabolism and distribution, and
these may help to explain differences observed with respect to their effects on tumor growth and metastasis in the transplantable
model. 相似文献
16.
Uptake and metabolism of saturated (16∶0, 18∶0) and unsaturated [18∶1(n−9), 18∶2(n−6), 18∶3(n−3)] fatty acids by cultured
epimastigotes ofTrypanosoma cruzi were studied. Between 17.5 and 33.5% of the total radioactivity of [1-14C]labeled fatty acids initially added to the culture medium was incorporated into the lipids ofT. cruzi and mostly choline and ethanolamine phospholipids. As demonstrated by argentation thin layer chromatography, gas liquid chromatography
and ozonolysis of the fatty acids synthesized, exogenous palmitic acid was elongated to stearic acid, and the latter was desaturated
to oleic acid and 18∶2 fatty acid. The 18∶2 fatty acid was tentatively identified as linoleic acid with the first bond in
the Δ9 position and the second bond toward the terminal methyl end. Exogenous stearic acid was also desaturated to oleic and
18∶2 fatty acid, while oleic acid was only converted into 18∶2. All of the saturated and unsaturated fatty acids investigated
were also converted to a small extent (2–4%) into polyunsaturated fatty acids. No radioactive aldehyde methyl ester fragments
of less than nine carbon atoms were detected after ozonolysis of any of the fatty acids studied. These results demonstrate
the existence of Δ9 and either Δ12 or Δ15 desaturases, or both, inT. cruzi and suggest that Δ6 desaturase or other desaturases of the animal type are likely absent in cultured forms of this organism. 相似文献
17.
Inositol phospholipids from carrot cell membranes grown in suspension cultured were purified by thinlayer chromatography (TLC)
or column chromatography and tentatively identified by co-migration on TLC with animal inositol phospholipid standards. For
more rigorous chemical characterization, carrot inositol phospholipids were then analyzed by negative ion fast atom bombardment
mass spectrometry (FABMS). One phosphatidylinositol (PI), two lysophosphatidylinositols (LPI), and one phosphatidylinositol
monophosphate (PIP) were identified in the carrot samples by the observation of ions [M-H]− and numerous fragment ions in the negative FAB mass spectra. MS/MS analysis were carried out to obtain further structural
information of these phospholipids using a double-focusing mass spectrometer in which the magnetic sector (B) and the electrostatic
analyzer (E) were scanned at a constant ratio (B/E). These B/E linked scans provided fragment ions of selected precursor ions
while eliminating matrix and other contaminating ions. No molecular ions were detected for lysophosphatidylinositol monophosphate
(LPIP) or phosphatidylinositol bisphosphate (PIP2), but fragment ions corresponding to these structures were observed. The primary fatty acids present in the carrot inositol
phospholipids were linoleic (18∶2) and palmitic (16∶0) acids, whereas animal lipids contained arachidonic (20∶4), stearic
(18∶0), linoleic, and palmitic acids. The only phosphatidylinositol found in carrot cells was palmitoyl linoleoyl PI. 相似文献
18.
Changes in dietary lipid intake are known to alter the fatty acid composition of cardiac muscle of various animals. Because
changes in cardiac muscle membrane structure and function may be involved in the pathogenesis of arrythmia and ischemia, we
have examined the effects of dietary lipid supplements on the phospholipid distribution and fatty acid composition of rat
atria and ventricle following 20 weeks feeding of diets supplemented with either 12% sunflower-seed oil or sheep fat.
Neither lipid supplement produced significant changes in the proportions of cholesterol, total phospholipids or phosphatidylcholine,
phosphatidylethanolamine or diphosphatidylglycerol,—the phospholipid classes that together account for more than 90% of the
total phospholipids of rat cardiac muscle. Significant changes were found in the profiles of the unsaturated fatty acids of
all 3 phospholipid components of both atria and ventricle. Although similar, the changes between these tissues were not identical.
However, in general, feeding a linoleic acid-rich sunflower seed oil supplement resulted in an increase in the ω-6 family
of fatty acids, whereas feeding the relatively linoleic acid-poor sheep fat supplement decreased the level of ω-6 fatty acids
but increased the levels of the ω-3 family, resulting in major shifts in the proportions of these families of acids. In particular,
the ratio of arachidonic acid: docosahexaenoic acid (20∶4, ω-6/22∶6, ω-3), which is higher in all phospholipids of atria than
ventricle, is increased by feeding linoleic acid, primarily by increasing the level of arachidonic acid in the muscle membranes.
As dosahexaenoic acid does not occur in the diet, the increase in this acid which occurs after feeding animal fat, presumably
arises from increased conversion of the small amounts of linolenic acid in all diets when the amount of linoleic acid present
is reduced. 相似文献
19.
Nanna Philipson Brandorff 《Lipids》1980,15(4):276-278
During pregnancy and lactation, female rats were fed diets containing either 28% partially hydrogenated marine oil (28MO),
2% arachis oil (2AO), or no fat (FF). Milk lipid composition was examined by gas chromatographic analysis of the gastric content
of 10-day-old suckling pups. An increase to 45% in the milk content of long chain monoenoic acids, 18∶1, 20∶1 and 22∶1, reflects
the fatty acid composition of the marine oil. Milk fatty acids of medium chain length comprised 6%, 31% and 24% of total fatty
acids in the (28MO), (2AO) and (FF) groups, respectively, suggesting that a high-fat diet (28MO) inhibits the lipid synthetic
activity of mammary glands. The amount of dienoic C18-acids (6%) in the group fed (28MO) containing no essential fatty acids (EFA) was similar to the amount of 18∶2 in the group
receiving a low-fat, EFA-rich diet (2AO). However, only half the dienoic acid from the milk of the (28MO)-fed animals was
linoleic acid, which was most likely mobilized from fat depots. 相似文献
20.
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