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1.
Unsaturated fatty acids of mycobacteria 总被引:4,自引:0,他引:4
The double bond locations have been determined for the mono-unsaturated fatty acids, C14 to C26 ofM. smegmatis andM. bovis BCG. The 14∶1 and 16∶1 fatty acids fromM. smegmatis are principally Δ10, while the 17∶1, 18∶1 and 19∶1 fatty acids from both organisms are Δ9. In the case ofM. smegmatis, the 20∶1, 22∶1 and 24∶1 fatty acids are principally Δ11, Δ13 and Δ15, respectively, while the 22∶1, 24∶1 and 26∶1 fatty acids of BCG are principally Δ13, Δ15 and Δ17, respectively. 相似文献
2.
The steryl ester and phospholipid fractions of the marine spongeAgelas conifera were isolated and analyzed. The fatty acyl components of the steryl ester and phospholipid fractions as determined by gas
chromatography and gas chromatography/mass spectrometry were very similar and consisted of 56.8 and 62.7% of C14−C20 acids (normal; branched, especiallyiso andanteiso; and monounsaturated, particularly Δ9 and Δ11 acids) and of 43.1 and 35.5% of C24−C26 acids (Δ5,9 diunsaturated acids), respectively. The major constituent fatty acids detected were 13-methyltetradecanoic,n-hexadecanoic, 10-methylhexadecanoic, 11-octadecenoic, 12-methyloctadecanoic, 5,9-pentacosadienoic and 5,9-hexacosadienoic
acids. The phospholipids isolated were identified as phosphatidylcholine (37%), phosphatidylserine (34%), phosphatidylethanolamine
(16%) and phosphatidylinositol (11%). The distribution of fatty acids within the phospholipid classes was also determined. 相似文献
3.
C. Bertoli L. B. Fay M. Stancanelli D. Gumy P. Lambelet 《Journal of the American Oil Chemists' Society》1998,75(8):1037-1040
The fatty acid composition, tocopherol and tocotrienol content, and oxidative stability of petroleum benzene-extracted Gevuina avellana Mol (Proteaceae) seed oil were determined. Positional isomers of monounsaturated fatty acids were elucidated by gas chromatography-electron
impact mass spectrometry after 2-alkenyl-4,4-dimethyloxazoline derivatization. This stable oil (Rancimat induction period
at 110°C: 20 h) is composed of more than 85% monounsaturated fatty acids and about equal amounts (6%) of saturated and polyunsaturated
(principally linoleic) fatty acids. Unusual positional isomers of monounsaturated fatty acids, i.e., C16:1 Δ11, C18:1 Δ12, C20:1 Δ11, C20:1 Δ15, C22:1 Δ17, and presumably C22:1 Δ19 were identified. The C18:1 Δ12 and C22:1 Δ19 fatty acids are described for the first time in G. avellana seed oil. While only minute quantities of α-, γ-tocopherols and β-, γ- and δ-tocotrienols were found, the oil contained a
substantial amount of α-tocotrienol (130 mg/kg). The potential nutritional value of G. avellana seed oil is discussed on the basis of its composition. 相似文献
4.
Monoethylenic fatty acids from herring oil were concentrated by chromatography by chromatography on silver nitratesilicic
acid columns. Examination of consecutive fractions by open tubular gas chromatography confirmed the preferential elution of
longer chain length esters and of esters within one chain length with the double bond closer to the terminal methyl group.
Isomeric monoethylenic fatty acids with double bonds in the positions closer to the carboxyl group than the approximate midpoint
of the even-numbered fatty acid chains could not be adequately separated by gas chromatography and were determined by ozonolysis.
The isomers observed are consistent with primary formation from saturated acids through the action of an enzyme specifically
removing hydrogen atoms in positions Δ9 and Δ10 relative to the carboxyl group. Chain extension of particular monoethylenic isomers by two carbon atoms in the C20 and longer chain lengths is apparently influenced by the position of the double bond.
This work was carried out in partial fulfillment of MSc requirements at Dalhousie University. 相似文献
5.
The fatty acids of rat skin surface lipids comprise four main skeletal types of chains which occur both as saturates and monoenes
and range from C12 to C38: straight even, straight odd, iso and anteiso (the latter two identified by GC retention data only). Two unidentified series
of branched monoenes also occur in trace amounts.
Reductive ozonolysis of monoenes reveals two characteristic double-bond position patterns, one for the straight even chain
series and the other for the straight odd chain series. The straight even chain pattern comprises four series, of which ω7
≫ω9>ω5>ω11; the straight odd chain series in contrast shows a large number of ω series with irregular distribution. The biosynthesis
of the even chain fatty acid monoenes can be thought of as occurring in two stages: synthesis of 14∶Δ9, 16∶Δ9, 18∶Δ9 and 20∶Δ9,
with 16∶Δ9 predominating; elongation of these chains mostly by 1, 2, or 3 C2 units but up to the unusually long lengths by 11 C2 units. For the formation of the former, two schemes by known pathways are proposed.
Iso and anteiso chains which are nearly all saturated comprised 1/3 the total fatty acids.
Special terms and abbreviations: Normal even=a straight chain with an even number of carbon atoms, normal odd=a straight chain
with an odd number of carbon atoms, ω=terminal carbon atom, iso=a straight chain with a methyl group at the ω−1 position,
anteiso=a straight chain with a methyl group at the w−2 position, Δn=a double bond between the nth and the (n+1)th carbon atom from the carbonyl group of the fatty acid or ester, ωn=a double bond between the ω∩nth and the ω-(n−1)th carbon atom where n is an integer, aldester=aldehyde methyl ester, Me=methyl, GLC=gas-liquid chromatography, TLC=thin-layer
chromatography. 相似文献
6.
The carbon chain length distribution and the double bond positional isomer composition of the monoenoic fatty acids of the
lipids of total human brain tissue have been determined using gas chromatography and gas chromatography/mass spectrometry
of the fatty acid methyl and picolinyl esters. The even chain length monoenoic C16 to C28 fatty acids contain predominantly two positional isomer series, the n−7 and n−9cis homologues, whose relative proportion varies significantly with chain length. The odd chain length long-chain fatty acids
consist of n−8 and n−10 isomers, whereas the odd chain length very long-chain (more than 22 carbon) fatty acids are n−7 and
n−9 isomers. 相似文献
7.
We applied a gas chromatography-mass spectrometry (GC-MS) method using dimethyl disulfide (DMDS) adducts and were able to
determine the double-bond positions in monounsaturated 2-hydroxy fatty acids (2-HFA). 2-HFA methyl esters, prepared from the
hydrolysate ofArabidopsis thaliana leaf glucosylceramides, were acetylated and methylthiolated. GC-MS analysis of the resulting DMDS adducts showed simple mass
spectra with recognizable molecular ions and a series of key fragment ions indicating the original double-bond positions in
the aliphatic chain. Based on this GC-MS elucidation, we confirmed thatArabidopsis leaf glucosylceramides have C22, C23, C24, C25, and C26 chain length 2-HFA with monounsaturation, and all their double bonds are placed at the n−9 position. This procedure is simple,
time efficient, and highly sensitive. 相似文献
8.
A. Grandgirard J. M. Bourre F. Julliard P. Homayoun O. Dumont M. Piciotti J. L. Sebedio 《Lipids》1994,29(4):251-258
During heat treatment, polyunsaturated fatty acids and specifically 18∶3n−3 can undergo geometrical isomerization. In rat
tissues, 18∶3 Δ9c, 12c, 15t, one of thetrans isomers of linolenic acid, can be desaturated and elongated to givetrans isomers of eicosapentaenoic and docosahexaenoic acids. The present study was undertaken to determine whether such compounds
are incorporated into brain structures that are rich in n−3 long-chain polyunsaturated fatty acids. Two fractions enriched
intrans isomers of α-linolenic acid were prepared and fed to female adult rats during gestation and lactation. The pups were killed
at weaning. Synaptosomes, brain microvessees and retina were shown to contain the highest levels (about 0.5% of total fatty
acids) of thetrans isomer of docosahexaenoic acid (22∶6 Δ4c, 7c, 10c, 13c, 16c, 19t). This compound was also observed in myelin and sciatic nerve, but to a lesser extent (0.1% of total fatty acids). However,
the ratios of 22∶6trans to 22∶6cis were similar in all the tissues studied. When the diet was deficient in α-linolenic acid, the incorporation oftrans isomers was apparently doubled. However, comparison of the ratios oftrans 18∶3n−3 tocis 18∶3n−3 in the diet revealed that thecis n−3 fatty acids were more easily desaturated and elongated to 22∶6n−3 than the correspondingtrans n−3 fatty acids. An increase in 22∶5n−6 was thus observed, as has previously been described in n−3 fatty acid deficiency.
These results encourage further studies to determine whether or not incorporations of suchtrans isomers into tissues may have physiological implications.
Presented in part at the 32nd International Conference on the Biochemistry of Lipids, 1991, Granada, Spain.
Delta nomenclature (Δ) is used fortrans polyunsaturated fatty acids to specify the position and geometry of ethylenic bonds. Polyunsaturated fatty acids containingtrans double bonds are abbreviated giving the locations of thetrans double bonds only; e.g., 20∶5 Δ17t 20∶5 Δ5c,8c,11c,14c,17t; 22∶5 Δ19t, 22∶5 Δ7c,10c,13c,16c,19t; 22∶6 Δ19t 22∶6 Δ4c,7c,10c,13c,16c,19t. 相似文献
9.
Nstor M. Carballeira Aikomari Guzmn Jordan T. Nechev Kantcho Lahtchev Albena Ivanova Kamen Stefanov 《Lipids》2000,35(12):1371-1376
The lipid composition of a Bacillus sp., isolated from Lake Pomorie in Bulgaria, was unusual and consisted of 26 different fatty acids between C12 and C26, with anteiso C15−C17 saturated fatty acids predominating. The furan fatty acid, 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid, was also identified,
a new finding for this genus. The hydrocarbons consisted of 30 different monounsaturated hydrocarbons, between C25 and C30, with the iso-iso, iso-anteiso, anteiso-anteiso, iso-normal, and anteiso-normal methyl branching for odd-numbered chains,
and the iso-iso, iso-anteiso, iso-normal, and anteiso-normal methyl branching for even-numbered chains. The double bond positions
in these hydrocarbons were determined by dimethyl disulfide derivatization followed by GC-MS, and the double-bond cis configuration was confirmed by infrared spectroscopy. Some previously unknown hydrocarbons in bacteria, such as (Z)-3,21-dimethyl-9-tricosene,
(Z)-3,21-dimethyl-10-tricosene, (Z)-2,24-dimethyl-11-pentacosene, and (Z)-2,25-dimethyl-13-hexacosene were identified. Sterols
were detected and were based on the sitosterol nucleus. 相似文献
10.
Wax esters were isolated from commercial orange roughy (Hoplostethus atlanticus) oil by column chromatography and fractionated by argentation thin layer chromatography. Following transesterification, the
resultant fatty acid methyl esters and fatty alcohols were analyzed by gas chromatography. both acyl- and alkyl-moieties were
mainly of the monoene structure within the 16∶1–22∶1 range. After derivatization, the positions of the double bonds of even
numbered fatty acid and fatty alcohol isomers were located by chromatography-mass spectrometry and compared.
Results of these positional analyses indicate that the primary desaturation reactions takes place in the Δ9 position of pre-existing
(C14 to C24) acyl chains. It is proposed that acyl components from 18∶1 are subjected to chain elongation to form a mixture of 24∶1 isomers
as the final product. Apart from the 24∶1 acyl moiety of the wax esters, in which the double bond was almost exclusively in
the Δ15 position, de novo biosynthetic reactions on acids and alcohols appear to yield related acyl- and alkyl-moieties of
resynthesized wax esters. 相似文献
11.
Marine fish have an absolute dietary requirement for C20 and C22 highly unsaturated fatty acids. Previous studies using cultured cell lines indicated that underlying this requirement in
marine fish was either a deficiency in fatty acyl Δ5 desaturase or C18–20 elongase activity. Recent research in turbot cells found low C18–20 elongase but high Δ5 desaturase activity. In the present study, the fatty acid desaturase/elongase pathway was investigated
in a cell line (SAF-1) from another carnivorous marine fish, sea bream. The metabolic conversions of a range of radiolabeled
polyunsaturated fatty acids that comprised the direct substrates for Δ6 desaturase ([1-14C]18∶2n−6 and [1-14C]18∶3n−3), C18–20 elongase ([U-14C]18∶4n−3), Δ5 desaturase ([1-14C]20∶3n−6 and [1-14C]20∶5n−3), and C20–22 elongase ([1-14C]20∶4n−6 and [1-14C]20∶5n−3) were utilized. The results showed that fatty acyl Δ6 desaturase in SAF-1 cells was highly active and that C18–20 elongase and C20–22 elongase activities were substantial. A deficiency in the desaturation/elongation pathway was clearly identified at the level
of the fatty acyl Δ5 desaturase, which was very low, particularly with 20∶4n−3 as substrate. In comparison, the apparent activities
of Δ6 desaturase, C18–20 elongase, and C20–22 elongase were approximately 94-, 27-, and 16-fold greater than that for Δ5 desaturase toward their respective n−3 polyunsaturated
fatty acid substrates. The evidence obtained in the SAF-1 cell line is consistent with the dietary requirement for C20 and C22 highly unsaturated fatty acids in the marine fish the sea bream, being primarily due to a deficiency in fatty acid Δ5 desaturase
activity. 相似文献
12.
This study has utilized radiolabeled analogues of arachidonic acid to study the substrate specificity of elongation of long-chain
polyunsaturated fatty acids. Human umbilical vein endothelial cells were incubated for 2–72 hr in medium supplemented with
0.9–2.6 μM [14C]fatty acid, and cellular glycerolipids were analyzed by gas-liquid chromatography with radioactivity detection. Elongation
of naturally occurring C20 polyunsaturated fatty acids occurred with eicosapentaenoate (20∶5(n−3))>Mead acid (20∶3(n−9))>arachidonate (20∶4(n−6)). Chain
length markedly influenced the extent of elongation of 5,8,11,14-tetraenoates (18∶4>19∶4>20∶4>21∶4); effects of initial double
bond position were also observed (6,9,12,15–20∶4>4,7,10,13–20∶4. Neither 5,8,14- nor 5,11,14–20∶3 was elongated to the extent
of 5,8,11–20∶3. Differences between polyunsaturated fatty acids were observed both in the initial rates and in the maximal
percentages of elongation, suggesting that the content of cellular C20 and C22 fatty acids may represent a balance between chain elongation and retroconversion.
Umbilical vein endothelial cells do not exhibit significant desaturation of either 22∶4(n−6) or 22∶5(n−3). By contrast, incubation
with 5,8,11,14-[14C]18∶4(n−4) resulted in formation of both [14C]20∶5(n−4) and [14C]22∶5(n−4). The respective time courses for the appearances of [14C]22∶5(n−4) and [14C]20∶5(n−5) suggests Δ6 desaturation of [14C]22∶4(n−4) rather than Δ4 desaturation of [14C]20∶4(n−4). 相似文献
13.
The total lipid fatty acids from the white shrimpPenaeus setiferus were found to contain several unusual dienoic fatty acid species. These included two methylene-interrupted species: Δ11,
14-C18∶2 (18∶2ω4) and δ13, 16-C20∶2 (20∶2ω4). Also found were several non-methylene-interrupted dienoic fatty acids including δ7, 11 and Δ7, 13-C20∶2, Δ7, 13-C21∶2, Δ7, 13, Δ7, 15, Δ9, 13, Δ9, 15, and Δ7, 17-C22∶2. Many minor C20∶2 non-methylene-interrupted dienes were found but could not be unequivocally characterized. 相似文献
14.
Norflurazon is a herbicide known to inhibit carotene biosynthesis and linolenic acid biosynthesis in plants. In the present
work, the effect of norflurazon on the metabolism of essential fatty acids was studied in isolated rat liver cells and in
rat liver microsomes, incubated with [1-14C] labeled linolenic acid (18∶3, n−3), dihomogammalinolenic acid (20∶3, n−6) and eicosapentaenoic acid (20∶5, n−3). Norflurazon
(0.1 mM, 1.0 mM) was found to inhibit essential fatty acid desaturation. The Δ6 desaturation is inhibited more efficiently
than the Δ5 and Δ4 desaturation. The chain elongation of essential C18 fatty acids to their C20 and C22 homoglogs was not inhibited by norflurazon. 相似文献
15.
Various straight-chain unsaturated fatty acids from C14 to C24 were evaluated for their ovipositional repellency against gravid females of the southern house mosquitoCulex quinquefasciatus Say, and the relationship between the structures of the fatty acids and their ovipositional repellency was determined. A double bond withZ configuration was prerequisite for an unsaturated fatty acid to be highly repellent;E isomers were less active or even inactive. No relationship was found between the repellency and the number of double bonds in the unsaturated fatty acids. In C18 monounsaturated fatty acids, (Z)-9 acid was more active than (Z)-11 and (Z)-6 acids, indicating that a double bond at the 9 position rendered an acid highly repellent. Among (Z)-9-alkenoic acids of different chain lengths, the most repellent was C18 acid which was also more active than (Z)-11-C20, (Z)-13-C22, and (Z)-15-C24 acids. Oleic[(Z)-9-octadecenoic]acid, which met all these criteria, was the most ovipositionally repellent among the unsaturated fatty acids tested.Diptera: Culicidae. 相似文献
16.
The phospholipids of the spongeStrongylophora durissima were analyzed. The major phospholipids present were phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine
(PS), phosphatidylglycerol (PG) and phosphatidylinositol (PI). The major fatty acid components of the phospholipids consisted
of short chain (C14−C19) and very long chain (C25−C30) “Demospongic” acids. Three novel branched Δ5 monounsaturated acids,Z-19-methyl-5-pentacosenoic,Z-19-methyl-5-hexacosenoic andZ-19-methyl-5-heptacosenoic acids were encountered in the sponge. The 3-saturated counterparts of these compounds, 19-methylpentacosanoic,
19-methylhexacosanoic and 19-methylheptacosanoic acids, as well as 19-methylpentacosanoic and 20-methyloctacosanoic acids
also are hitherto undescribed acids present in the sponge. Trace amounts of 2 very long chain acids also were detected and
their structures tentatively assigned as 19,21-dimethylheptacosanoic and 20,22-dimethyloctacosanoic acids. The distribution
of these fatty acids according to phospholipid head groups also was described. 相似文献
17.
Kumar D. Mukherjee 《Lipids》1986,21(5):347-352
Lipids in developing seeds ofSinapis alba contain appreciable proportions of (n−7)octadecenoic (vaccenic) acid besides its (n−9) isomer (oleic acid), whereas the constituent
very long chain (>C18) monounsaturated fatty acids of these lipids are overwhelmingly composed of the (n−9) isomers. Cotyledons of developingSinapis alba seed use [1-14C]acetate, [1-14C]malonate or [1,3-14C]malonyl-CoA for de novo synthesis of palmitic, stearic and oleic acids and for elongation of preformed oleic, vaccenic and
stearic acids to their higher (n−9), (n−7) and saturated homologs, respectively. Moreover, elongation of preformed (n−7)palmitoleic
acid to vaccenic acid is observed. Stepwise C2-additions to preformed oleoyl-CoA by acetyl-CoA or malonyl-CoA yielding (n−9)icosenoyl-CoA, (n−9)docosenoyl-CoA and (n−9)tetracosenoyl-CoA
are by far the most predominant reactions catalyzed by the elongase system, which seems to have a preference for oleoyl-CoA
over vaccenoyl-CoA as the primer. The pattern of14C-labeling of the very long chain fatty acids formed from either acetate or malonate shows a close analogy in the mode of
elongation of monounsaturated and saturated fatty acids. 相似文献
18.
R. G. Ackman S. N. Hooper J. Hingley 《Journal of the American Oil Chemists' Society》1971,48(12):804-806
A Canadian Atlantic herring oil hydrogenated for margarine use to an iodine value of 76 and melting point of 32.5 C was found
to have 30% saturated acids and 66% monounsaturated fatty acids. The monounsaturated fatty acids could be analytically determined
ascis andtrans isomers by open tubular gas liquid chromatography.Trans acids were 33% of the C16 and C18 monounsaturated acids, and 32 and 28%, respectively, of the C20 and C22 monounsaturated acids. After separation of geometric isomers by Florisil-silver nitrate chromatography the positional isomers
in each class were determined by oxidative fission. The double bond positions of the originalcis fatty acids were largely retained in bothcis andtrans isomers, but additional isomers were observed, especially in thetrans fatty acids. 相似文献
19.
Philip E. Pfeffer Philip E. Sonnet Daniel P. Schwartz Stanley F. Osman David Weisleder 《Lipids》1992,27(4):285-288
Substitution of a hydroxyl group at thebis homoallylic position (OH group located three carbons away from the olefinic carbon) in C18 unsaturated fatty acid esters (FAE) induces a 0.73±0.05 ppm upfield and a 0.73±0.06 ppm downfield shift on the δ and ε olefinic13C resonances relative to the unsubstituted FAE, respectively. If the hydroxyl group is located on the carboxyl side of the
double bond of thebis homoallylic hydroxy fatty acid esters (BHAHFA), the olefinic resonances are uniformly shifted apart by [|1.46+|Δδdbu‖] where Δδdbu represents the absolute value of the double bond resonance separation in the unsubstituted FAE and 1.46 ppm is the sum of
the absolute values of the δ and ε shift parameters. With hydroxyl substitution on the terminal methyl side of the double
bond, the olefinic shift separation is equal to [|1.46−|Δδdbu‖]. In homoallylic (OH group located two carbons away from the olefinic carbon) substituted FAE the γ and δ induced hydroxyl
shifts for thecis double bond resonances are +3.08 and −4.63 ppm, respectively while thetrans double bond parameters are +4.06 and −4.18 ppm, respectively. The double bond resonance separation in homoallylic hydroxy
fatty acid esters (HAHFA) can be calculated from the formula [|7.71−|Δδdbu‖] forcis and [|8.24−|Δδdbu‖] for thetrans case when the OH substitution is on the carboxyl side of the double bond. Conversely, when the OH resides on the terminal
methyl side, the double bond shift separations forcis andtrans isomers are [|7.71+|Δδdbu‖] and [|8.24+|Δδdbu‖], respectively. The derived shift parameters can verify the positions of both the double bond and hydroxyl substitution
from the olefinic resonance separation in long-chain fatty acid derivatives, obviating the need for destructive analytical
methods.
Reference to brand or firm name does not constitute endorsement by the United States Department of Agriculture over others
of a similar nature not mentioned. 相似文献
20.
Sterols were analyzed from four phytoplankton strains which are under investigation as possible sources of food for oysters
in culture. One strain ofPyramimonas contained only 24-methylenecholesterol as a major sterol component.Pyramimonas grossii, Chlorella autotrophica andDunaliella tertiolecta each contained a complex mixture of C28 and C29 sterols with Δ7, Δ5,7 and Δ5,7,9(11) nuclear double bond systems. Sterols were found both with and without the C-22 side chain double bond. Ergosterol and 7-dehydroporiferasterol
were the principal sterols in each of the latter three species, which also contained the rare tetraene sterols, 24-methylcholesta-5,7,9(11),22-tetraen-3β-ol
and 24-ethylcholesta-5,7,9(11),22-tetraen-3β-ol. 相似文献