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1.
The incorporation of 1-14C-acetate into the many fatty acids of the marine spongeMicrociona prolifera was investigated. Probable precursors of 26∶2Δ5,9 and 26∶3Δ5,9,19 showed high levels of radioactivity, supporting the following pathways for the biosynthesis of C26 acids: $$\begin{array}{*{20}c} {16:0 \to \to \to 26:0 \to 26:1\Delta 9 \to 26:2\Delta 5,9} \\ {16:1\Delta 9 \to \to \to 26:1\Delta 19 \to } \\ {26:2\Delta 9,19 \to 26:3\Delta 5,9,19} \\ \end{array}$$ Degradation of the unsaturated C26 acids at their double bonds showed that the14C was concentrated near the carboxyl end of the chain. Hence, chain elongation was the major mechanism for acetate incorporation into these acids. 相似文献
2.
The syntheses of 15-tetracosynoic acid (ω9-tetracosynoic acid) and 19-octacosynoic acid (ω9-octacosynoic acid) are described.
These alkynoic acids are to be tritiated to the corresponding alkenoic acids, which will be used as metabolic precursors of
housefly pheromone components. The final step in each synthesis involved the coupling of 1-decyne to the lithio-salt of the
appropriate ω-bromoacid. Homologation of dibromoalkanes was accomplished with triphasic catalytic displacement of bromide
by cyanide ion. Oxidation of a bromo-alcohol to a bromoacid was performed in benzene with KMnO4 and 18-crown-6 ether.
Mention of a company name or product in this paper does not imply endorsement by the U.S. Department of Agriculture. 相似文献
3.
A new method for the synthesis ofcis-3,cis-5- andtrans-3,cis-5-tetradecadienoic acids, pheromone constituents of the dermestid beetlesAttagenus elongatulus andA. megatoma, was developed. The syntheses are based upon the formation oftrans-2-tetradecen-5-ynoic acid by reaction of 4-bromo-2-butenoic acid with 1-decynylmagnesium bromide. The enynoic acid undergoes
alkali-induced isomerization to yield a mixture of acids from whichcis-3- andtrans-3-tetradecen-5-ynoic acids were separated in 31% and 34% yields, respectively. Methyltrans-2-tetradecen-5-ynoate was similarly prepared and isomerized to furnish methylcis-3-tetradecen-5-ynoate in 8% yield. Reduction of the tetradecenynoic acids with dicyclohexylborane gavecis-3,cis-5-andtrans-3,cis-5-tetradecadienoic acids in 4% and 39% yields, respectively. A better yield (49%) in the reduction ofcis-3-tetradecen-5-ynoic acid tocis-3,cis-5-tetradecadienoic acid was obtained by hydrogenation over Lindlar's catalyst. Similarly, reduction of methylcis-3-tetradecen-5-ynoate with disiamylborane gave 22% methylcis-3,cis-5-tetradecadienoate. 相似文献
4.
C. R. Scholfield 《Journal of the American Oil Chemists' Society》1972,49(10):583-585
The products formed by hydrogenation of methylcis-9,trans-12- andtrans-9,trans-12-octadecadienoates with nickel and platinum catalysts have been compared with those from methyl esters of the naturally
occurring all-cis linoleate. Hydrogen uptake is slower for thetrans isomers. Much of the monoene consisted of esters with double bonds at the 9 and 12 positions with their original geometric
configurations. Monoenoic esters with double bonds at the 10 and 11 positions were predominatelytrans and apparently formed by conjugation before hydrogenation. Nickel produced more isomerization than platinum but less than
previously reported for copper. With both catalysts hydrogenation proceeded both directly and through conjugated intermediates,
in contrast to copper in which all hydrogenation is believed to follow conjugation.
Presented at the AOCS Meeting, Los Angeles, April 1972.
ARS, USDA. 相似文献
5.
Methyl esters prepared from the seed oil of the coniferTaxus baccata L. were found by gas liquid chromatography to contain 12% of a component which, when isolated by preparative thin layer chromatography
and characterized by mass spectrometry, ozonolysis and nuclear magnetic resonance, was identified ascis-5,cis-9-octadecadienoic acid. 相似文献
6.
Seed oil ofXeranthemum annuum (family Compositae) contains a number of unusual fatty acids in addition to palmitic, stearic, oleic, linoleic and linolenic.
These acids includecis-5,cis-9,cis-12-octadecatrienoic, 5%;cis-9-l,10-l-epoxyoctadecanoic, 3%;cis-9-l,10-l-epoxy-cis-12-octadecenoic (coronaric), 8%; andcis-12-d,13-d-epoxy-cis-9-octadecenoic (vernolic), 2%; as well as a mixture of two hydroxy acids, 11%. The absolute configurations of the two 9,10-epoxy
acids are established for the first time.
Presented in part at the AOCS Meeting in Cincinnati, October 1965.
No. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
7.
Robert L. Wolff 《Journal of the American Oil Chemists' Society》1994,71(10):1129-1134
To understand the heat-inducedcis-trans isomerization of ethylenic bonds in octadecatrienoic acids, pine seed oil, which contains the unusual nonmethylene-interrupted
pinolenic (cis-5,cis-9,cis-12 18∶3) acid as a major component, was heated under vacuum at 240°C for 6 h together with linseed and borage oils. As a
results, a small percentage of pinolenic acid undergoescis-trans isomerization. The main isomer that accumulates is thetrans-5,cis-9,trans-12 18∶3 acid. Minor amounts of the three mono-trans isomers are also present. Identification of isomers was realized by combining gas-liquid chromatography on a CP Sil 88 capillary
column, argentation thin-layer chromatography and comparing the equivalent chainlengths of artifacts to those of isomers present
in NO2-isomerized pine seed oil. Hydrazine reduction was used to demonstrate that there was no positional shift of double bonds.
Heat-induced geometrical isomerization of pinolenic acid differs from that of α- and γ-linolenic acids in at least two aspects.
The reaction rate is slower (about one-fourth), and mono-trans isomers are formed in low amounts. 相似文献
8.
Methyl esters from seed oils of four Chenopodiaceae species are unusual in that they contain methylcis-5-hexadecenoate (4.6–12%) and methyl 5-octadecenoate (1.1–1.2%). There are indications of small amounts of 18∶25,9 and 18∶35, 9, 12 along with unsaturated acids commonly found in seed oils-oleic (14–21%), linoleic (53–57%) and linolenic (3.5–7.8%). Fatty
acid composition of the oils was determined by gas chromatography, and positions of the double bonds were established by application
of gas chromatography-mass spectrometry to the methoxylated methyl esters.
N. Market. Nutr. Res. Div., ARS, USDA. 相似文献
9.
The marine spongeXestospongia halichondroides contains 13% 28∶3Δ5,9,19, 27% 26∶2Δ5,9, and 21% 26∶1Δ17 in its total fatty acids. Thecis-5,cis-9,cis-19-octacosatrienoic acid structure is unknown in other living organisms. 相似文献
10.
11.
Mixtures of triglycerides containing deuterium-labeled hexadecanoic acid (16∶0), octadecanoic acid (18∶0),cis-9-octadecenoic acid (9c–18∶1),cis-9,cis-12-octadecadienoic acid (9c, 12c–18∶2) andcis-12,trans-15-octadecadienoic acid (12c,15t–18∶2) were fed to two young-adult males. Plasma lipid classes were isolated from samples
collected periodically over 48 hr. Incorporation and turnover of the deuterium-labeled fats in plasma lipids were followed
by gas chromatography-mass spectrometry (GC-MS) analysis of the methyl ester derivatives. Absorption of the deuterated fats
was followed by GC-MS analysis of chylomicron triglycerides isolated by ultracentrifugation.
Results were the following: (i) endogenous fat contributed about 40% of the total fat incorporated into chylomicron triglycerides;
(ii) elongation, desaturation and chain-shortened products from the deuterated fats were not detected; (iii) the polyunsaturated
isomer 12c,15t–18∶2 was metabolically more similar to saturated and 9c–18∶1 fatty acids than to 9c,12c–18∶2 (iv) relative
incorporation of 9c,12c–18∶2 into phospholipids did not increase proportionally with an increase of 9c,12c–18∶2 in the mixture
of deuterated fats fed; (v) absorption of 16∶0, 18∶0, 9c–18∶1, 9c,12c–18∶2 and 12c,15t–18∶2 were similar; and (vi) data for
the 1- and 2-acyl positions of phosphatidylcholine and for cholesteryl ester fractions reflected the known high specificity
of phosphatidylcholine acyltransferase and lecithin:cholesteryl acyltransferase for 9c,12c–18∶2.
These results illustrate that incorporation of dietary fatty acids into human plasma lipid classes is selectively controlled
and that incorporation of dietary 9c,12c–18∶2 is limited. These results suggest that nutritional benefits of diets high in
9c,12c–18∶2 may be of little value to normal subjects and that the 12c,15t–18∶2 isomer in hydrogenated fat is not a nutritional
liability at the present dietary level. 相似文献
12.
Open-tubular gas chromatographic analysis of fatty acids in the lipids from the seeds of 20 species of Gymnospermae showed
that they all contained nonmethylene-interrupted polyenoic (NMIP) acids as minor components and palmitic, oleic, linoleic
and α-linolenic acids as major components. The NMIP acids have an additional 5,6-ethylenic bond in ordinary plant unsaturated
fatty acids and the following C2 elongation acids:cis-5,cis-9-octadecadienoic acid (5,9–18∶2) (I); 5,9,12–18∶3 (II); 5,9,12,15–18∶4, 5,11–20∶2, 5,11,14–20∶3 (III); and 5,11,14,17–20∶4
(IV). The main NMIP acids found in neutral lipids are I in two species ofTaxus, II in seven species of Pinaceae, III in two species of Podocarpaceae,Torreya nucifera, Cycas revoluta, andGinkgo biloba, and III and IV in each of three species of Taxodiaceae, and Cupressaceae. The polar lipids constitute the minor fraction
of seed lipids in general. The content and composition of NMIP acids in these lipids differe considerably from those in neutral
lipids. Analysis of the partial cleavage products of triacylglycerols showed that the NMIP acids distribute mainly in the
1,3-position. 相似文献
13.
Kohei Yamamoto Akira Shibahara Akiko Sakuma Takao Nakayama Goro Kajimoto 《Lipids》1990,25(10):602-605
The pulp lipids of jujube (Zizyphus jujuba var.inermis) fruit have been shown by chromatographic, spectrometric and chemical analyses to contain a series ofcis-monoenoic fatty acids with n−5 unsaturation as major acyl moieties. The total concentration of these n−5 fatty acids, such
as 14∶1n−5, 16∶1n−5 and 18∶1n−5, ranged from 22 to 54% of total fatty acids in the pulp lipids of 11 different sources. The
main component of the n−5 homologues was 16∶1n−5 in all cases. Other monoenoic acids with n−7 unsaturation, namely palmitoleic
(cis-9-hexadecenoic) acid andcis-vaccenic (cis-11-octadecenoic) acid, as well as with n−9 unsaturation, namely oleic acid, were also identified. In the seed lipids of jujube
fruit, none of the n−5 monoenoic acids could be detected. Thus the jujube pulp lipids are characterized by the predominance
of n−5 monoenoic acid isomers. 相似文献
14.
Marcel S. F. Lie Ken Jie M. S. K. Syed Rahmatullah 《Journal of the American Oil Chemists' Society》1995,72(2):245-249
Enrichment ofcis-5 polyunsaturated fatty acids [20:3(5c,11c,14c), 4.3% and 20:4(5c,11c,14c,17c), 11.3%] fromBiota orientalis seed oil was carried out by lipase-catalyzed selective esterification and hydrolysis reactions. Lipases fromRhizomucor miehei (Lipozyme),Candida cylindracea and porcine pancreas were used. Lipozyme-catalyzed esterification ofBiota fatty acids withn-butanol inn-hexane allowed 20:3 and 20:4 (as fatty acids) to be enriched to a maximum level of 52.9%, and in the presence ofC. cylindracea lipase 61.5% enrichment was achieved. Esterification with pancreatic lipase was poor with low levels of enrichment of 20:3
and 20:4 (22%). A multigram scale esterification of the free fatty acids fromBiota seed oil by repeated treatment of the isolated fatty acid fraction withn-butanol inn-hexane in the presence ofC. cylindracea lipase furnished an enrichment yield of 72.5% of a mixture of 20:3 and 20:4 fatty acids. Urea fractionation of the free fatty
acids ofBiota oil gave an initial enriched fraction of 20:3 (9.5%) and 20:4 (25.2%) which, upon treatment withC. cylindracea lipase inn-butanol andn-hexane, gave an enriched fraction of 85.3% of 20:3 and 20:4 fatty acids. Partial hydrolysis of the triglycerides ofBiota oil byC. cylindracea lipase in potassium phosphate buffer at 25°C resulted in a 2.8-fold enrichment ofcis-5 polyunsaturated fatty acids (40.8% of 20:3 and 20:4) as contained in the unhydrolyzed acylglycerol fractions. 相似文献
15.
A. C. Lanser 《Lipids》1982,17(8):524-528
The deposition oftrans-8-octadecenoate-8(9)-3H (8t-18∶1-3H) was compared tocis-9-octadecenoate-10-14C (9c-18∶1-14C) in the major egg yolk neutral lipids and phospholipids and in organ lipids from the laying hen.trans-8-Octadecenoate was preferentially incorporated into only the phosphatidylethanolamines (PE), whereas discrimination against
8t-18∶1-3H occurred in the phosphatidylcholines (PC), triglycerides (TG) and cholesteryl esters (CE). The 1-acyl position of both PE
and PC contained three times more 8t-18∶1-3H than 9c-18∶1-14C. Almost total exclusion of the 8t-18∶1-3H from the 2-acyl position of these phospholipids was found. Preferential incorporation of 9c-18∶1-14C occurred at the combined 1- and 3-acyl positions and at the 2-acyl position of yolk TG. Tissue lipid analyses indicated
that there was preferential deposition of 9c-18∶1-14C into all organs. Individual liver lipid classes displayed the same relative order of discrimination against 8t-18∶1-3H as did egg yolk lipids (CE>TG>PC>PE). 相似文献
16.
Dietary deficiency of essential fatty acids of the n−3 and n−6 series is known to promote a compensatory increase in polyenoic
fatty acids of the n−9 series in the lipids of mammalian tissues. In the present study long-chain n−9 polyenes were found
to be normal components of the epididymis and especially of sperm isolated from that tissue, in healthy, well-fed, fertile
rats maintained on essential fatty acid-sufficient diets. The n−9 polyenes occurred in large concentrations in the choline
glycerophospholipids (CGP), the major phospholipid class of spermatozoa in epididymalcauda, and were highly concentrated in plasmenylcholine, the major subclass of CGP. The uncommon polyene 22∶4n−9 was found in the
highest proportion, followed in order of relative abundance by 22∶3n−9, 20∶3n−9 and 24∶4n−9. These polyenes were probably
derived from oleate (18∶1n−9) in much the same way as long-chain polyenes of the n−6 and n−3 series are derived from linoleate
(18∶2n−6) and linolenate (18∶3n−3), respectively. 相似文献
17.
Methylcis-9,cis-15-octadecadienoate was partially deuterated with nickel catalyst, and the product was separated into saturate, monoene and
diene fractions. Monoenes were separated intotrans andcis fractions, and dienes intotrans,trans, cis,trans andcis,cis fractions. Monoene isomers with double bonds at the 9 and 15 positions predominated in bothcis- andtrans-monoene fractions. Considerable amounts of isomers with double bonds situated on either side of the original 9 and 15 positions
were found in thetrans-monoene fraction. Diene was extensively isomerized to positional and geometrical isomers, and deuterium was incorporated
into these isomers. Double bond migration was greatest intrans,trans-dienes and smallest incis,cis-dienes. The amount of deuterium in the dienes was proportional to the extent of isomerization experienced by the dienes.
ARS, USDA. 相似文献
18.
19.
Judd C. Nevenzel 《Lipids》1970,5(3):308-319
Wax esters occur as a major lipid-type in at least 30 species of marine animals, distributed among 17 orders and 3 phyla.
They are of limited usefulness as a chemotaxonomic character, since only in two suborders, the calanoid copepods, Calanoidei,
and the toothed whales, Odontoceti, do the wax esters occur in all members so far examined. In bony fishes their occurrence
in muscle correlates better with mesopelagic habitat and vertical migration patterns than with taxonomy. Homologs with 21
to 44 total carbon atoms have been reported, but the usual range for the wax esters in copepods and fish is C30–C42. In fishes the muscle wax esters contain predominantly one and two double bonds per molecule, while in roe lipids up to 65%
of the homologs contain three or more double bonds. The component alcohols are saturated and monounsaturated, with 16∶0 and
18∶1 as the usual major constituents. The fatty acids are more diverse, but 18∶1 is most often the main component, and 16∶1
and 20∶1 are frequent major constituents; polyunsaturated acids make up 1–12% in fish muscle and whale oils and up to 45%
in fish roe wax esters. Possible functions of the wax esters are for buoyancy, as energy reserves and for thermal insulation.
In vitro, various tissues of marine bony fishes synthesize wax esters from long chain alcohols and fatty acids, without activation.
A competing pathway for the long chain alcohols in vivo is their catabolic oxidation to the corresponding fatty acids. The
key to the accumulation of wax esters is to be sought in the metabolism of the long chain alcohols, their biosynthesis and
esterification vs. their catabolism.
Presented at the 60th AOCS Annual Meeting, San Francisco, April 1969, as part of a Symposium on Natural Waxes. 相似文献