Composition of wax esters,triglycerides and diacyl glyceryl ethers in the jaw and blubber fats of the Amazon River dolphin (Inia geoffrensis)

The lower jaw fat of the Amazon River dolphinInia geoffrensis contains 52.8% wax ester, 44.7% triglyceride and 2.5% diacyl glyceryl ether, while its dorsal blubber fat is >98% triglyceride. Examination of the intact lipids, the derived fatty acids and the derived fatty alcohols by gas chromatography reveals that the blubber triglycerides show characteristics of freshwater fish fats, but the jaw fat lipids have several distinctive features. Jaw fat wax esters, triglycerides and diacyl glyceryl ethers are all rich in C₁₀, C₁₂ and C₁₄ fatty acids and contain no polyunsaturated acids. The fatty alcohols in the wax esters are over 90% saturated. The major carbon numbers in the jaw fat triglycerides (C₃₈–C₄₆) are considerably lower than those of the blubber triglycerides (C₄₈–C₅₄). The possible adaptation of the jaw lipids for use in the underwater echolocation process of this dolphin is discussed.     

Lipids of freshwater dolphinSotalia fluviatilis: Comparison of odontocete bioacoustic lipids and habitat

The melon and jaw lipids of the freshwater dolphinSotalia fluviatilis are composed mainly of isovaleroyl wax esters and diisovaleroyl triglycerides. The blubber fat contains only a trace of wax ester and is mostly tri- (long chain) and monoisovaleroyl triglycerides. Detailed gas liquid chromatographic analyses of the intact wax esters and triglycerides and of the derived fatty acids and fatty alcohols indicate common compositional patterns in the wax esters and triglycerides of the respective head lipids. Both odd and even long chain (C₁₂−C₁₆) iso-structures are prominent in the melon and jaw lipids, but only higher odd chain length iso-acids are major components in the blubber.Sotalia fluviatilis (family Delphinidae) andInia geoffrensis (family Platanistidae) share the same freshwater habitat in the upper Amazon River, and both utilize echolocation to navigate and to find food. Comparison of their respective bioacoustical lipid compositions shows distinctive types of head fats,Sotalia being rich in iso-5∶0 andIndia lacking iso-5∶0. This indicates that isovaleric acid per se has no obligatory role in dolphin echolocation.     

Cuticular lipids of insects: V. Cuticular wax esters of secondary alcohols from the grasshoppersMelanoplus packardii andMelanoplus sanguinipes

Wax esters of secondary alcohols constitute 18–20% of the cuticular lipid extract ofMelanoplus packardii and 26–31% of the cuticular lipids ofMelanoplus sanguinipes. The total number of carbons in the wax esters range from 37–54 with 41 predominating in both species. The fatty acids ofM. packardii wax esters are 16∶0, 18∶0, 14∶0, 20∶0 and 12∶0 in decreasing quantity. The fatty acids ofM. sanguinipes wax esters are 18∶0, 20∶0, 16∶0 22∶0, 14∶0, 19∶0 and 17∶0 in decreasing quantity. The secondary alcohols from the wax esters ofM. packardii are C₂₅, C₂₃ and C₂₇ in decreasing quantity, and the secondary alcohols of theM. sanguinipes are C₂₃, C₂₅, C₂₁, C₂₇, C₂₄, C₂₂ and C₂₆ in decreasing quantity. Each secondary alcohol consists of two to four isomers with the hydroxyl group located near the center of the chain. Montana Agriculture Experiment Station, Journal Series No. 332.     

Occurrence,function and biosynthesis of wax esters in marine organisms

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.     

Occurrence of wax esters and 1-O-alkyl-2,3-diacylglycerols in goat epididymal sperm plasma membrane

Two unusual lipid classes were detected by thin-layer chromatography in the neutral lipids derived from goat cauda-epididymal sperm plasma membrane. The lipids were identified as wax esters and 1-O-alkyl-2,3-diacylglycerols based on chromatographic properties, identity of their hydrolysis products, and infrared/¹H nuclear magnetic resonance spectral evidence. The membrane containedca. 3 and 5 μg/mg protein of wax esters and alkyldiacylglycerols, respectively. The relative proportions of wax esters and alkyldiacylglycerols in the total neutral lipids were 1.5% and 2.4%, respectively. The lipids contained fatty acids with chain lengths of C₁₄ to C₂₂. The major fatty acids of the wax esters were 14∶0, 16∶0, 16∶1ω7, 18∶0 and 18∶1ω9. The fatty acids in alkyldiacylglycerol were 16∶0, 18∶0, 22∶5ω3 and 22∶6ω3. Alkyldiacylglycerol was particularly rich in docosahexaenoic acid 22∶6ω3) representing 30% of the total fatty acids. The alcohols of wax ester were all saturated with C₂₀–C₂₉ carbon chains. The deacylated products derived from alkyldiacylglycerols were identified as hexadecyl, octadecyl and octadec-9′-enyl glycerol ethers.     

Molecular species of wax esters in jaw fat of atlantic bottlenose dolphin,Tursiops truncatus

The jaw fat of the Atlantic bottlenose dolphin (Tursiops truncatus) contains unusual wax esters which can be separated into short chain (<C₂₄) and long chain (>C₂₄) fractions by thin layer chromatography. The short chain wax esters (28 wt. %) have been characterized as a 72∶24∶4 mixture of isovaleroyl, isobutoryl, and 2-methylbutyrol, esters of C₁₄–C₁₈ n- and iso-alcohols. The intact <C₂₄ esters have been resolved into individual molecular species by gas liquid chromatography on open-tubular polyester columns. The long chain wax esters (12 wt. %) contain C₁₀–C₂₂ n- and iso-acids esterified to the same C₁₄–C₁₈ n- and iso-alcohols. Gas liquid chromatography of the intact, hydrogenated >C₂₄ esters on a short JXR column has characterized them according to carbon number and the number of methyl branches they contain.     

Linear, steroidal, and triterpene esters, and steryl glycosides from Festuca argentina

Ester waxes and steryl glycosides of the grass Festuca argentina were studied. Saponification of the waxes from the petroleum ether extract led to n-hexacosanol as the major single linear alcohol, along with pentacyclic triterpenols, such as β-amyrin, germanicol, isobaurenol, lupeol, hopenol-a and hopeol, and low amounts of sterols, such as cholesterol, campesterol, stigmasterol, sitosterol and dihydrositosterol, identified by gas chromatography/mass spectrometry (GC/MS). Fatty acids were identified as methyl esters as C_12∶0, C_14∶0, C_16∶0, C_18∶0, C_18∶2, and C_20∶0. The occurrence of a wide chainlength range of fatty acids and a single linear alcohol closely matched for other reports on the tribe Festuceae. On the contrary, pentacyclic triterpenols with a variety of skeletons, especially isobauerenol, are not usual as esters of fatty acids in the Gramineae. Low amounts of steryl glycosides were also obtained from the methylene chloride percolate of the methanol extract. Upon acetylation followed by hydrolysis, aglycones were identified by capillary gas-liquid chromatography (GLC) and GC/MS. As Δ⁷-cholesterol, campesterol, stigmasterol, sitosterol, dihydrositosterol, and the sugars as glucose, xylose, and arabinose by GLC of the respective alditol acetates. This is the first report on the linear, steryl, and triterpenyl esters of F. argentina. It is noteworthy that Δ⁷-steryl glycosides are rare, and steryl monoarabinosides have not been proviously reported on the family Gramineae.     

Trans-6-hexadecenoic acid and the corresponding alcohol in lipids in the sea anemoneMetridium dianthus

Trans-6-hexadecenoic acid was found in polar lipids, triglycerides, was esters and diacylglyceryl ethers of the sea anemoneMetridium dianthus from Passamaquoddy Bay. The corresponding alcomaquoddy Bay. The corresponding alcohol also apparently occurs in the wax esters of this species. The long-chain (C₂₀, C₂₂) monoethylenic alcohols reported for other species of sea anemones from neighboring waters were absent and the major alcohol and glyceryl ether chain both had 16∶0 structures. The isomers of C₁₈ and C₂₀ monoethylenic fatty acids in polar lipids and triglycerides were unusual in their high proportion of theω ₇ isomer. These two lipids also contained higher proportion of the polyunsaturated fatty acids than the others.     

The monounsaturated acyl- and alkyl-moieties of wax esters and their distribution in commercial orange roughy (Hoplostethus atlanticus) oil

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.     

Properties, composition, and analysis of grain sorghum wax

Grain sorghum wax has been judged to be a potential source of natural wax with properties similar to carnauba wax. Approximately 0.16–0.3% (w/w) wax can be extracted from grain sorghum depending on the efficiency of the organic solvents. Although the melting points of carnauba wax and sorghum wax are similar, i.e., 78–86 and 77–85°C, respectively, they differ in acid values, i.e., 2–10 and 10–16, respectively, and saponification numbers, i.e., 77–95 and 16–49, respectively. Improved knowledge of the properties, composition, and analysis of grain sorghum wax would assist in efforts for industrial application of this product. Major components of sorghum wax are hydrocarbons, wax esters, aldehydes, free fatty alcohols, and FFA. The hydrocarbons consist mainly of C₂₇ and C₂₉, and the aldehydes, alcohols, and acids are mainly C₂₈ and C₃₀. The wax esters are mostly esters of C₂₈ and C₃₀ alcohols and acids.     

Comparative studies on the fatty acid composition of moderately and extremely thermophilic bacteria

The fatty acids of three strains of extremely thermophilic bacteria and three strains of moderately thermophilic bacteria were examined by gas liquid chromatography. All the thermophiles contained straight, iso, and ante-iso branched fatty acids. Iso C_17∶0 acid was abundant in both the moderately thermophilic strains (10–33%) and the extremely thermophilic strains (50–61%). The pair of fatty acids iso C_15∶0 and iso C_17∶0 was the predominant pair in both the moderately (34–64%) and extremely (76–87%) thermophilic strains. The pair of fatty acids ante-iso C_15∶0 and ante-iso C_17∶0 was present in larger amount in moderately (25–34%) than in extremely (8.5–15%) thermophilic strains. No hydroxy cyclopropane, or unsaturated fatty acids were found. One extreme thermophile,Flavobacterium thermophilum HB-8 was grown at 6 different culture temperatures from 49–82 C, and the changes of its fatty acid composition were studied. The ratios of iso C_17∶0/iso C_15∶0 and ante-iso C_17∶0/ante-iso C_15∶0 were much greater at higher culture temperatures, indicating chain elongation.     

Lipid,sterol and fatty acid composition of antarctic krill (Euphausia superba Dana)

The lipid classes, fatty acids of total and individual lipids and sterols of Antarctic krill (Euphausia superba Dana) from two areas of the Antarctic Ocean were analyzed by thin layer chromatography (TLC), gas liquid chromatography (GLC) and gas liquid chromatography/mass spectrometry (GLC/MS). Basic differences in the lipid composition of krill from the Scotia Sea (caught in Dec. 1977) and krill from the Gerlache Strait (caught in Mar. 1981) were not observed. The main lipid classes found were: phosphatidylcholine (PC) (33–36%), phosphatidylethanolamine (PE) (5–6%), triacylglycerol (TG) (33–40%), free fatty acids (FFA) (8–16%) and sterols (1.4–1.7%). Wax esters and sterol esters were present only in traces. More than 50 fatty acids could be identified using GLC/MS, the major ones being 14∶0, 16∶0, 16∶1(n−7), 18∶1(n−9), 18∶1(n−7), 20∶5(n−3) and 22∶6(n−3). Phytanic acid was found in a concentration of 3% of total fatty acids. Short, medium-chain and hydroxy fatty acids (C≤10) were not detectable. The sterol fraction consisted of cholesterol, desmosterol and 22-dehydrocholesterol.     

A process for the preparation of food-grade rice bran wax and the determination of its composition

A two-step method was developed for the preparation of food-grade wax. The first step involved the solventdefatting of crude wax, which gave a dark brown, dry, powdered wax with a m.p. of 75–79°C. The major impurity in the defatted wax was the dark brown resinous matter. In the second step, the resinous matter was removed by bleaching with sodium borohydride in isopropanol. This step yielded a pale yellow, odorless wax with purity higher than 99% and with a m.p. of 80–83°C. The resinous matter was a mixture of aliphatic aldehydes, fatty alcohols, and FA. High-temperature GC analysis of the purified rice bran wax indicated that it contained 11 major and 9 minor types of saturated wax esters. The major and minor peaks contained C₄₄–C₆₄ and C₄₅–C₅₉ wax esters, respectively. Rice bran wax was mainly a mixture of saturated esters of C₂₂ and C₂₄ FA and C₂₄ to C₄₀ aliphatic alcohols, with C₂₄ and C₃₀ being the predominant FA and fatty alcohol, respectively. The alcohol portion of the wax esters also contained small amounts of branched and odd carbon number fatty alcohols.     

Leaf wax of oats

Leaf wax of oats (Kelsey variety) consists of hydrocarbons (5%), esters (10%), free alcohols (45%), free acids (2.5%), β-diketone (5.5%), hydroxy-β-diketones (2.5%), and unidentified (29%). Wax on leaf blades contains more free alcohols than wax on leaf sheaths, and wax on the flag leaf sheath contains more β-diketone than wax on the rest of the plant. Principal hydrocarbons are C₂₉, C₃₁, and C₃₃. The esters, mainly C₄₄–C₄₈ and C₅₂, are probably C₁₈–C₂₂ and C₂₆ esters of hexacosanol. Free alcohols are almost entirely hexacosanol. The β-diketone is hentriacontane-14, 16-dione. Hydroxy β-diketones are a mixture of 5-, 6- and 7-hydroxyhentriacontane-14, 16-diones in the proportions 58∶35∶7. The wax also contains a small amount (0.5%) of 1,16-hexacosanediol. IRCC No. 13472.     

A simple method for the quantitative isolation and resolution of unesterified fatty acids from fats and oils

The unesterified fatty acids (UFA) present in fats and oils are isolated cleanly and without the formation of detectable artifacts due to saponification. The lipid (≤0.5 g) dissolved in 5 ml of n-hexane is passed over a 300-mg bed of Celite impregnated with saturated, aqueous Na₃PO₄ so that the solution passes through the bed in 3–4 min. After the bed has been washed, the UFA are freed from their salts by pumping of HC1 vapor over the bed. The acids are eluted with CH₂Cl₂ and subsequently separated underivatized by gas liquid chromatography. The C₁₀ through C_18.3 acids are separated in <15 min. Recovery of the C₁₀-C_18∶0 and C_18∶1, C_18∶2 and C_18∶3 acids added to fatty acid-free fats and oils in several concentrations was nearly 100%     

The fatty acids of wax esters and sterol esters from vernix caseosa and from human skin surface lipid

Separation of sterol esters from wax esters in the lipids of vernix caseosa and adult human skin surface was accomplished by column chromatography on MgO. The fatty acids of the sterol esters and wax esters of both samples were separated into saturates and monoenes, and examined in detail by gas liquid chromatography (GLC). The saturated fatty acids of the wax esters of vernix caseosa and of adult human skin surface were remarkably similar. They ranged in chain length from at least C₁₁ to C₃₀, six skeletal types being present: straight even, straight odd, iso, anteiso, other monomethyl branched and dimethyl branched. A large number of patterns of monoenes were observed, each pattern consisting of desaturation of a specific chain at Δ6 or Δ9 plus its extension or degradation products. The mole per cent of the total Δ6 and Δ9 patterns of wax ester fatty acid monoenes of vernix caseosa were 87% and 12%, respectively, and 98% and 1%, respectively, for adult human skin surface lipid. The sterol ester fatty acids of vernix caseosa were much different from those of adult human skin surface: vernix caseosa saturates were largely branched and of lengths greater than C₁₈, whereas the saturates of adult human surface lipid resembled the wax ester fatty acids. Of the vernix caseosa monoene patterns, the mole per cent was 30% Δ6 and 70% Δ9, whereas of the adult human skin surface sterol ester fatty acids 89% were Δ6 and 11% Δ9. Chain extension was particularly pronounced in the sterol ester fatty acid monoenes of vernix caseosa amounting to 7–8 C₂ units in some cases. The fatty acids of the sterol esters of both vernix caseosa and adult human skin surface appear to be derived from the sebaceous gland and from the keratinizing epidermis, but those of the wax esters are from the sebaceous glands only.     

Fatty alcohols in capelin,herring and mackerel oils and muscle lipids: II. A comparison of fatty acids from wax esters with those of triglycerides

The fatty acids recovered from the triglycerides and wax esters of common northwest Atlantic copepods are compared with the fatty acids of wax esters recovered intact from certain fish skin and body lipid, and from commercial fish oils. The fish species, herring, capelin and mackerel, all feed on copepods, and many resemblances of the copepod lipid fatty acids to those of a previous analysis of similar copepods suggest that the basic dietary fat input for these fish may be quite constant. The two copepod fatty acid analyses differed quantitatively in triglyceride 20∶1 and 22∶1 and also in 20∶5ω3 and 22∶6ω3, confirming the primary role of the wax esters in copepods. Selectivity factors are discussed in comparing the copepod wax ester fatty acids with the fatty acids of the wax esters recovered intact from the fish lipids and oils. The basic role of copepods in supplying all types of fatty acids to fish depot fats is considered to be strongly supported by these findings.     

Isovaleroyl triglycerides from the blubber and melon oils of the beluga whale (Delphinapterus leucas)

The fatty acid compositions of the blubber and melon oils from the beluga whale (Delphinapterus leucas) have been determined by gas liquid chromatography (GLC). The melon oil contains a high level (60.1 mole %) of isovaleric acid, substantial amounts of long chain branched acids (16.9%), and very little polyunsaturated material (0.5%). The blubber oil contains less isovaleric (13.2%), fewer long chain branched acids (2.7%), and appreciable amounts (10.9%) of the polyunsaturated acids typical of marine oils. The blubber and melon oils were also examined for lipid class composition by thin layer chromatography on silicic acid, direct GLC of the hydrogenated oil, and gel permeation chromatography. Both oils are composed almost entirely of triglycerides, which can be separated chromatographically into molecules containing 0, 1 and 2 isovaleric acid moieties. No triisovalerin could be detected. The blubber oil contains 68.9 mole % normal triacyl-, 24.2% diacyl-monoisovaleroyl-, and 7.0% monoacyl-diisovaleroyl-triglycerides (acyl=long chain acid). Monoacyl-diisovalerin constitutes 86.7 mole % of the melon oil. This unusual compound may play a role in the echolocation system of the beluga whale.     

Variations in lipid composition and sound velocity in melon from the North Atlantic pilot whale,Globicephala melaena melaena

Nonpolar lipids and sound velocity at different distances from the skin surface within a sample of pilot whale melon were studied. Thin layer chromatography, sensitive radioisotopic methods, and an ultrasonic echo scanner were used. Wax esters had a maximum concentration at 11–12 cm from the skin surface. Non- and monoisovalero triglycerides both exhibited a minimum at 8–10 cm, whereas the diisovalero species increased steadily from the skin surface towards the center of the pilot whale head. A minimum of sound velocity, ca. 1340 m/s, was found at 9–11 cm, thus coinciding with a region rich in isovaleric acid esterified in wax and diisovalero triglycerides. These findings are compatible with predictions based on the known correlations between lipid structure and sound velocity. Consequently, additional evidence for refraction of sound in pilot whale melon is presented. This is important in understanding the system of echolocation of toothed whales.     

The high content of monoene fatty acids in the lipids of some midwater fishes: Family myctophidae

The total lipids of eleven species of Myctophids caught at depths between 20 and 700 m in the northern Pacific Ocean were analyzed using silicic acid column chromatography (lipid classes) and capillary gas chromatography (fatty acid and fatty alcohol composition). The major components in the lipid classes were triacylglycerols or wax esters; triacylglycerols were the dominant acyl neutral lipids (68.1–96.1%) in eight species, and wax esters were found as the dominant lipid (85.5–87.9%) in three species. The major fatty acids and alcohols contained in the was esters of the three fishes were 18:1n–9, 20:1n–9, 20:1n–11, and 22:1n–11 for fatty acids, and 16:0, 18:1, 20:1, and 22:1 for fatty alcohols. Fatty acids in the triacylglycerols ranging from C₁₄ to C₂₂ were predominantly of even chain length. The major components were 16:0, 16:1n–7, 18:1n–9, 20:1n–11, 22:1n–11, 20:5n–3 (icosapentaenoic acid), and 22:6n–3 (docosahexaenoic acid). In both the triacylglycerols and the wax esters, the major fatty components were monoenoic acids and alcohols. It is suggested from the lipid chemistry of the Myctophids that they may prey on the same organisms as the certain pelagic fishes such as saury and herring, because the large quantities of monoenoic fatty acids are similar to those of saury, herring, and sprats whose lipids originate from their prey organisms such as zooplanktons which are rich in monoenoic wax esters.