Wax Ester Fraction Research Articles

Branched-chain fatty acids in the vernix caseosa and meconium of infants born at different gestational ages.

The functional lipid components found in breast milk, vernix caseosa, and meconium are Branched‐chain Fatty Acids (BCFA). The goal of this study was to establish the existence of BCFA in vernix and meconium in infants born at different gestational ages. TLC plates and GC‐MS were examined for the lipids in vernix caseosa and meconium. The results indicated that there were nine BCFA in vernix caseosa, including iso‐12:0, anteiso‐13:0, iso‐14:0, iso‐15:0, anteiso‐15:0, iso‐16:0, anteiso‐17:0, iso‐18:0, and iso‐20:0. Five BCFA (iso‐12:0, anteiso‐13:0, iso‐14:0, iso‐15:0, and anteiso‐15:0) were not contained in the meconium, suggesting that some of the BCFA may be digested and consumed by infants. In the vernix caseosa, the content of BCFA in triacylglycerol (TAG) and free fatty acid (FFA) was 15.59% and 11.82%, respectively. The vernix caseosa's wax ester fraction contained the highest content of BCFA, reaching up to 16.81%. The carbon chain length of fatty acids (FA) ranged from 12 to 24 in the vernix caseosa and 14 to 22 in meconium samples. The gestational age was likely to affect BCFA concentrations, with the vernix caseosa and meconium BCFA content being significantly higher in full‐term infants than in preterm infants (p < .001). Further research is required into the relationship between BCFA and gut microbiotas.

Chemical and Sensory Characterization of Nine Spanish Monovarietal Olive Oils: An Emphasis on Wax Esters

Olive oil is an essential part of the so-called “Mediterranean diet”, purportedly one of the healthiest gastronomic traditions in the world. The wax content in olive oil is regulated under European Union directives, and it is used as a purity parameter for extra-virgin and virgin olive oils. The wax profile may also help the characterization of monovarietal olive oils. In this study, monovarietal oils were extracted from the fruits of nine native Spanish olive varieties (‘Arbequina’, ‘Argudell’, ‘Empeltre’, ‘Farga’, ‘Manzanilla’, ‘Marfil’, ‘Morrut’, ‘Picual’ and ‘Sevillenca’), and their chemical and sensory attributes were determined. Total wax content in oil was cultivar-dependent and ranged widely between 26 (‘Manzanilla’) and 144 mg kg−1 (‘Arbequina’), while it was negligible in ‘Picual’ oil. The wax ester fraction was comprised largely of phytol-containing diterpene esters, with phytyl vaccinate and phytyl arachidate being the most common components of this non-polar fraction in all nine olive oils assessed. A direct relationship between phytyl esters and the sensory perception of “ripe fruit” notes was also observed.

Identification of Phytyl Vaccinate as a Major Component of Wax Ester Fraction of Extra Virgin Olive Oil

Despite the great efforts devoted to the study of the chemical composition of olive oil, the identification of minor components is still incomplete. Within this context, the characterization of esters of fatty alcohols with fatty acids is far from complete. The objective of this study is to investigate phytyl wax esters profile of extra‐virgin olive oils, in order to provide an update on the current knowledge of the chemical composition of this fraction. Extra‐virgin olive oil waxes are transesterificated with HCl/isobutanol and isobutyl esters are analyzed by GC‐FID and GC‐MS using two capillary columns with different polarity. A comparison of the GC retention times with analytical standards together with the acquired mass spectra allow to identify and confirm, for the first time, phytyl vaccinate as the relevant unknown peak detected in the wax esters fraction of extra‐virgin olive oils. Additionally, the analysis of the composition of aliphatic alcohols obtained by hydrolysis of waxes reveals that the preponderant compound is C24 alcohol derived from lignoceryl palmitate, which is practically the only wax really present, while the low level of C28 alcohol confirms that extra‐virgin olive oils of good quality contain negligible amounts of long‐chain waxes which are derived from C28 alcohol.Practical Applications: Phytil vaccinate has been shown for the first time as a relevant component of apolar olive oil fraction, highlighting the importance of studying the biosynthesis of the esterified apolar fraction of extra virgin olive oils since acids esterified with diterpenes are quantitatively different from those found in triglycerides. From a nutritional point of view, the identification and characterization of the diterpenic esters profiles of the apolar fraction of extra virgin olive oils is of particular interest, especially considering that these compounds contribute to the reduction of blood cholesterol levels.This study has demonstrates, for the first time, the presence of phytyl vaccinate as a relevant component of apolar olive oil fraction.

Assessment of storage lipid accumulation patterns in eucalanoid copepods from the eastern tropical Pacific Ocean

Members of the copepod family Eucalanidae are widely distributed throughout the world׳s oceans and have been noted for their accumulation of storage lipids in high- and low-latitude environments. However, little is known about the lipid composition of eucalanoid copepods in low-latitude environments. The purpose of this study was to examine fatty acid and alcohol profiles in the storage lipids (wax esters and triacylglycerols) of Eucalanus inermis, Rhincalanus rostrifrons, R. nasutus, Pareucalanus attenuatus, and Subeucalanus subtenuis, collected primarily in the eastern tropical north Pacific near the Tehuantepec Bowl and Costa Rica Dome regions, noted for its oxygen minimum zone, during fall 2007 and winter 2008/2009. Adult copepods and particulate material were collected in the upper 50m and from 200 to 300m in the upper oxycline. Lipid profiles of particulate matter were generated to help ascertain information on ecological strategies of these species and on differential accumulation of dietary and modified fatty acids in the wax ester and triacylglycerol storage lipid components of these copepods in relation to their vertical distributions around the oxygen minimum zone. Additional data on phospholipid fatty acid and sterol/fatty alcohol fractions were also generated to obtain a comprehensive lipid data set for each sample. Rhincalanus spp. accumulated relatively large amounts of storage lipids (31–80% of dry mass (DM)), while E. inermis had moderate amounts (2–9% DM), and P. attenuatus and S. subtenuis had low quantities of storage lipid (0–1% DM). E. inermis and S. subtenuis primarily accumulated triacylglycerols (>90% of storage lipids), while P. attenuatus and Rhincalanus spp. primarily accumulated wax esters (>84% of storage lipids). Based on previously generated molecular phylogenies of the Eucalanidae family, these results appear to support genetic predisposition as a major factor explaining why a given species accumulates primarily triacylglycerols or wax esters, and also potentially dictating major fatty acid and alcohol accumulation patterns within the more highly modified wax ester fraction. Comparisons of fatty acid profiles between triacylglycerol and wax ester components in copepods with that in available prey suggested that copepod triacylglycerols were more reflective of dietary fatty acids, while wax esters contained a higher proportion of modified or de novo synthesized forms. Sterols and phospholipid fatty acids were similar between species, confirming high levels of regulation within these components. Similarities between triacylglycerol fatty acid profiles of E. inermis collected in surface waters and at >200m depth indicate little to no feeding during their ontogenetic migration to deeper, low-oxygen waters.

Wax Esters from the Marine Copepod Calanus finmarchicus Reduce Diet-Induced Obesity and Obesity-Related Metabolic Disorders in Mice1–3

We showed previously that dietary supplementation with oil from the marine zooplankton Calanus finmarchicus (Calanus oil) attenuates obesity, inflammation, and glucose intolerance in mice. More than 80% of Calanus oil consists of wax esters, i.e., long-chain fatty alcohols linked to long-chain fatty acids. In the present study, we compared the metabolic effects of Calanus oil-derived wax esters (WE) with those of purified eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) ethyl esters (E/D) in a mouse model of diet-induced obesity. C57BL/6J mice received a high-fat diet (HFD; 45% energy from fat). After 7 wk, the diet was supplemented with either 1% (wt:wt) WE or 0.2% (wt:wt) E/D. The amount of EPA + DHA in the E/D diet was matched to the total amount of n–3 (ω-3) polyunsaturated fatty acids (PUFAs) in the WE diet. A third group was given an unsupplemented HFD throughout the entire 27-wk feeding period. WE reduced body weight gain, abdominal fat, and liver triacylglycerol by 21%, 34%, and 52%, respectively, and significantly improved glucose tolerance and aerobic capacity. In abdominal fat depots, WE reduced macrophage infiltration by 74% and downregulated expression of proinflammatory genes (tumor necrosis factor-α, interleukin–6, and monocyte chemoattractant protein–1), whereas adiponectin expression was significantly upregulated. By comparison, E/D primarily suppressed the expression of proinflammatory genes but had less influence on glucose tolerance than WE. E/D affected obesity parameters, aerobic capacity, or adiponectin expression by <10%. These results show that the wax ester component of Calanus oil can account for the biologic effects shown previously for the crude oil. However, these effects cannot exclusively be ascribed to the content of n–3 PUFAs in the wax ester fraction.

Age and ethnic variations in sebaceous lipids

This study was conducted to compare lipid components of sebum from persons from three ethnic backgrounds—Caucasian, African American and Northern Asian. Men and women with no acne in two age groups (18‒25 y and 35‒45 y) were recruited. Skin surface hydration (SkiCon 200EX and NovaMeter), barrier function (Delfin VapoMeter), high-resolution clinical imaging, self-assessments and two pairs of sebutapes on the forehead that extracted the lipids on the surface of their skin were used. Significant differences (p < 0.05) in skin hydration between African Americans and Caucasians in both age groups were noted, with the order from highest to lowest absolute values: African American > Northern Asian > Caucasian. Transepidermal water loss (TEWL) measurements demonstrated that African Americans and Caucasians were significantly different (p < 0.05), with the trend being the inverse of the hydration trend—Caucasian > Northern Asian > African American, which would indicate better barrier function for African Americans with a lower TEWL. African American women had more total lipid production than Northern Asian or Caucasian women. When analyzing the three lipid classes (free fatty acids, triglycerides and wax esters), the trend became significant (p < 0.05) in the wax ester fraction when directly comparing African Americans with Caucasians. Additionally, six lipids were identified in the wax ester fractions that were significantly different in quantity (p < 0.05) between African Americans and Caucasians. These results identified significant differences in sebaceous lipid profiles across ethnic groups and determined that the differences correlated with skin barrier function.

Exceptional lipid storage mode of the copepod Boeckella poopoensis in a pampean salt lake, Argentina

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 15:275-281 (2012) - DOI: https://doi.org/10.3354/ab00432 Exceptional lipid storage mode of the copepod Boeckella poopoensis in a pampean salt lake, Argentina Germán A. Kopprio1,4,*, Gerhard Kattner2, Martin Graeve2, R. Hugo Freije3, Rubén J. Lara1,4 1Consejo Nacional de Investigaciones Científicas y Técnicas, Instituto Argentino de Oceanografía, Bahía Blanca B8000FWB, Argentina 2Ecological Chemistry, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven 27570, Germany 3Environmental Chemistry, Universidad Nacional del Sur, Bahía Blanca B8000CPB, Argentina 4Wetland Dynamics, Leibniz Center for Tropical Marine Ecology, Bremen 28359, Germany *Email: gkopprio@criba.edu.ar ABSTRACT: The lipid biochemistry of zooplankton was investigated in Lake Chasicó, a pampean salt lake in Argentina. The lipid biomass of the zooplankton community was dominated by the calanoid copepod Boeckella poopoensis. The major storage lipids during winter were wax esters and triacylglycerols, which reached up to 59 and 37% of the total lipids, respectively. A striking feature of the zooplankton fatty acid composition was the extraordinarily high level of 18:4(n‑3) and 20:4(n-3) fatty acids, the highest ever reported for the latter in zooplankton. During winter, 20:4(n-3) accounted on average for 20% of the total fatty acids in the wax ester fraction and 7% in the triacylglycerols. The close relationship (r = 0.83, p < 0.001) between the 2 fatty acids implies the biosynthesis of 20:4(n-3) in B. poopoensis by chain elongation of 18:4(n-3), a dietary precursor and flagellate marker. The accumulation of 20:4(n-3) may be also partially related to B. poopoensis grazing on heterotrophic protozoa or non-flagellated chlorophytes, although this fatty acid was almost absent in the seston fraction. In summer, wax esters were slightly lower (45%), compensated by higher phospholipid levels. The 16:0 fatty alcohol moiety was predominant in the wax esters of all samples, corroborating the opportunistic feeding behavior of B. poopoensis. The high amounts of wax esters in zooplankton are typical of marine species, suggesting that the wax ester biosynthesis of B. poopoensis and the extraordinary fatty acid composition are adaptations to the unstable environmental conditions of salt lakes. KEY WORDS: Polyunsaturated fatty acids · Biosynthesis · Trophic markers · Wax esters · 20:4(n-3) Full text in pdf format PreviousNextCite this article as: Kopprio GA, Kattner G, Graeve M, Freije RH, Lara RJ (2012) Exceptional lipid storage mode of the copepod Boeckella poopoensis in a pampean salt lake, Argentina. Aquat Biol 15:275-281. https://doi.org/10.3354/ab00432 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 15, No. 3. Online publication date: June 06, 2012 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2012 Inter-Research.

Lipid biomarkers reveal geographical differences in food supply to the cold-water coral Lophelia pertusa (Scleractinia)

Despite its importance as an ecological engineer, little is known about the feeding eco- logy of the widespread reef framework-forming cold-water coral Lophelia pertusa. This is the first study to compare lipid signatures of L. pertusa from different areas in the North Atlantic using sam- ples from 2 sites in the eastern Atlantic and 2 seamounts in the western Atlantic. Lipid samples were collected in February, May, July and November from the Mingulay reef complex off western Scot- land, but no clear seasonal pattern was observed. High lipid content and large wax ester fractions were recorded from all sites, with the highest values recorded at the shallowest site (Mingulay). Here the prevalence of copepod lipid biomarkers — monounsaturated fatty acids 20:1(n-9) and 22:1(n-11) and their fatty alcohols — indicates L. pertusa feeds predominantly on calanoid copepods. At deeper offshore sites, the abundance of the fatty acid 18:1(n-9) and fatty alcohol 16:0 suggest a significant dietary input from non-calanoid copepods. Our results imply that the shallow Mingulay site is likely to receive a greater input of fresh surficial material and a higher abundance of herbivorous calanoid copepods, while at the deeper sites, carnivorous or omnivorous non-calanoid copepods are likely to be more abundant. L. pertusa therefore appears to be an opportunistic feeder capable of taking a variety of zooplankton prey. Further investigation is required to assess site-specific dependence on prey sources.

Wax ester fraction of edible oils: Analysis by on‐line LC‐GC‐MS and GC×GC‐FID

AbstractThe wax ester fraction of various plant oils was isolated by normal‐phase HPLC (NPLC) on‐line coupled to GC via the on‐column interface and applying concurrent eluent evaporation. The esters were analyzed by on‐line NPLC‐GC‐MS and by comprehensive two‐dimensional GC with flame ionization detection (GC×GC‐FID) off‐line combined with NPLC‐GC. GC×GC‐FID enables to group the various classes of wax esters, in particular the phytol esters, geranylgeraniol esters and the straight‐chain esters of palmitic acids and the unsaturated C18 acids. Optimization of the GC×GC columns and the conditions must take into account the limited thermostability of the diterpene esters. Chromatograms are shown for a range of oils, with particular focus on the various classes of wax esters in olive oil and the geranylgeraniol esters 22:0 and 24:0 in a variety of oils.

Atlantic salmon, Salmo salar, utilizes wax ester-rich oil from Calanus finmarchicus effectively

Against a background of decreasing availability of fish oils for use in aquaculture, the present study was undertaken to examine whether a wax ester-rich oil derived from the calanoid copepod Calanus finmarchicus, could be used effectively by Atlantic salmon when supplied in their diet. Individually tagged Atlantic salmon of initial weight around 500 g were divided into replicate tanks of two dietary groups and fed either a fish oil supplemented diet, or an experimental diet coated with Calanus oil. Wax esters accounted for 37.5% of the lipids in the Calanus oil diet but were absent from the fish oil diet in which triacylglycerols (TAG) were the major lipid class. Over the feeding period (140 days) the salmon fed fish oil displayed a greater increase in length, but there was no significant difference between the two groups in weight gained. The specific growth rates (0.75) and the feed conversion ratio of fish fed the two diets were similar throughout the study. No differences were observed in the apparent digestibility coefficients (ADC) of fish fed Calanus oil or fish oil. The ADC of fatty acids decreased with chain length and increased with unsaturation. Long-chain alcohol utilization showed a similar tendency although there was a notable difference in that saturated long-chain alcohols were utilized better than the comparable fatty acid homologue. In fecal lipid of fish fed Calanus oil, the content of 16:0 alcohol decreased in both the free long-chain alcohol and wax ester fractions, while the corresponding fatty acid increased in the feces of both dietary groups of fish. In contrast, the proportion of the 22:1 n−11 alcohol increased in both fecal wax esters and free long-chain alcohol fractions whereas 22:1 n−11 fatty acid displayed no accumulation. The observed patterns of fatty acid and long-chain alcohol compositions in fecal lipid compared to those of the initial dietary lipid are consistent with the digestive lipases of salmon preferentially hydrolyzing esters containing polyunsaturated fatty acid (PUFA) moieties. The wax esters of Calanus oil contained substantial amounts of the n−3 PUFA, 20:5 n−3 and 22:6 n−3, that were effectively deposited in muscle and liver tissues. No major differences were seen in either lipid content/lipid classes or in gross fatty acid composition of these tissues between the two dietary groups. It is concluded that that Atlantic salmon in seawater can effectively utilize diets in which a major lipid component is derived from zooplankton rich in wax ester without any detrimental change in growth or body lipid composition. This finding gives support to the use of lipid from zooplankton from high latitudes as an alternative or as a supplement to fish oil and a provider of long-chain n−3 PUFA in diets for use in salmon aquaculture.

Analysis of the wax ester fraction of olive oil and sunflower oil by gas chromatography and gas chromatography‐mass spectrometry

AbstractThe wax ester fractions of solvent‐extracted sunflower oil and “extra virgin” olive oil were obtained by solid‐phase extraction and subsequently subjected to gas‐chromatographic and gas chromatographic‐mass spectrometric analysis. The comprehensive qualitative analysis of these fractions, which was carried out by the interpretation of mass spectral data, revealed several types of wax esters. In olive oil, shortchain, even‐numbered wax esters, saturated and unsaturated long‐chain, even‐numbered wax esters, benzyl esters, and the diterpenic esters phytyl and geranylgeranyl ester (the latter as a minor component) are present. With the exception of benzyl esters, all these esters occur in sunflower oil as well, but in considerably different amounts compared to those in olive oil. Whereas unsaturated wax esters are present in a negligible amount, diterpenic esters, mainly geranylgeranyl esters, represent the major part of the wax ester fraction.

Increased control of the sheep biting louse Bovicola (Damalinia) ovis with deltamethrin formulated in a fractionated wool grease carrier

The synthetic pyrethroid deltamethrin (DM) containing a trace of [ 14C]-DM was formulated with non-oxidised sterol and wax ester fractions (F1) of wool grease and as the commercial preparation ‘Clout-S’. These were applied as a ‘backline’ strip to sheep immediately after shearing and the concentration of [ 14C]-DM at meridians adjacent to the application strip and at 1/4 and 3/4 of the dorsal–ventral distance was determined. The F1 formulation resulted in significantly greater lateral spread of DM with less remaining at the application site (66±8% of dose) 98 days after treatment compared to ‘Clout-S’ (94±3% dose). Autoradiographic examination of treated wool demonstrated that there was more DM in the lower half of the wool staple when formulated in F1 compared to ‘Clout-S’. Greater mortality occurred when sheep biting lice Bovicola (Damalinia) ovis were exposed in vitro to wool containing DM from F1 compared to ‘Clout-S’ treated sheep. In field trials there was increased efficacy against synthetic pyrethroid resistant B. ovis with F1 formulation than with ‘Clout-S’. The study has demonstrated that synthetic pyrethroid availability, and therefore efficacy, can be significantly increased when the insecticide is formulated in a ‘carrier’ with the physicochemical characteristics of wool grease.

Lipid composition of the extracellular matrix of Botrytis cinerea germlings

Six simple lipid classes (mono-, di- and tri-acylglycerols, free fatty acids, free fatty alcohols and wax esters) were identified by TLC in the extracellular matrix of Botrytis cinerea germlings and the molecular components of each class were characterized using GC-MS. The relative amounts of fatty acids and fatty alcohols within each lipid class were determined by GC-FID. Over all the lipid classes, the most abundant saturated fatty acids were palmitic (ca. 30%) and stearic acid (ca. 22%). Palmitoleic and oleic acids made up ca. 21% and 24% (respectively) of the free fatty acids, while erucic (ca. 4.1%) and linoleic (ca. 3.6%) acids were the most abundant unsaturated fatty acids in the acylglycerides. The acylglycerides also contained almost 35% long chain fatty acids (C20:0 to C28:0). Six fatty acids were identified which had odd-numbered carbon chain lengths (C15:0, C17:0, C19:0, C21:0, C23:0 and C25:0). Of these, pentacosanoic acid made up almost 14% of the fatty acids in the acylglycerides. Three methyl-branched chain fatty acids, namely isopalmitic, isoheptadecanoic and anteisopalmitic, were identified in the ECM, all in small amounts. Of the fatty alcohols identified, only palmityl and stearyl alcohols were found in the free form (ca. 57% and 43%, respectively) but arachidyl alcohol (ca. 47%) and 1-octacosanol (ca. 30%) were the most abundant fatty alcohols found in the wax ester fraction.

Isolation and Characterization of Wax Esters in Fennel and Caraway Seed Oils by SPE-GC

Summary A rapid method for the isolation and quantitative determination of wax esters in vegetable oils was developed. For the first time wax esters in oils were separated from the triglyceride matrix by means of solid-phase extraction, which allows rapid sample preparation in parallel and therefore a high sample throughput. The thus obtained wax ester fractions of fennel and caraway seed oils were analyzed by high temperature gas chromatography. GC-MS analyses were carried out using electron impact ionization in order to characterize the wax ester fraction. With respect to the results of the GC-MS analyses different isomers of saturated wax esters with the same carbon number were observed. Additional monounsaturated wax esters with an unsaturated fatty acid moiety were identified.

Isolation and Characterization of Wax Esters in Fennel and Caraway Seed Oils by SPE-GC

A rapid method for the isolation and quantitative determination of wax esters in vegetable oils was developed. For the first time wax esters in oils were separated from the triglyceride matrix by means of solid-phase extraction, which allows rapid sample preparation in parallel and therefore a high sample throughput. The thus obtained wax ester fractions of fennel and caraway seed oils were analyzed by high temperature gas chromatography. GC-MS analyses were carried out using electron impact ionization in order to characterize the wax ester fraction. With respect to the results of the GC-MS analyses different isomers of saturated wax esters with the same carbon number were observed. Additional monounsaturated wax esters with an unsaturated fatty acid moiety were identified.

Determination of the wax ester content in olive oils. Improvement in the method proposed by EEC regulation 183/93.

A simpler and faster procedure than the official one described in document IV of European Economic Community Regulation 183/93 is proposed. The wax ester fraction is isolated from triglycerides using a commercially available silica gel column and carbon tetrachloride as eluent. The recovered wax ester fraction, with the addition of a suitable internal standard solution, is analyzed by gas chromatography. A column with a 65% phenyl methyl silicone stationary phase allows a satisfying separation of wax ester fraction in comparison with both a steryl ester and a light fraction eluted before the internal standard. Furthermore, also the single components of the wax ester fraction are suitably separated.

Very Long-Chain Methyl-Branched Alcohols and Their Acetate Esters in the Internal Lipids of Lepidopteran Pupae: Cochylis hospes, Diatraea grandiosella, Homoeosoma electellum, Heliothis virescens and Helicoverpa zea

Very long-chain methyl-branched alcohols (VLMA; C35 > C46) and their acetate esters were characterized in the internal lipids of developing mid-stage pupae of the banded sunflower moth Cochylis hospes, the southwestern corn borer Diatraea grandiosella, the sunflower moth Homoeosoma electellum, the tobacco budworm Heliothis virescens and the corn earworm Helicoverpa zea. Minor amounts of long-chain methyl-branched alcohols (LMA; C25–C34) were also found largely in H. virescens and H. zea. Five homologous series of primary alcohols were identified in all species: n-alcohols, internally branched monomethyl alcohols, 2 series of dimethyl branched alcohols, and a series of trimethyl branched alcohols. The 4 methyl-branched series were characterized, e.g., by one of their major components: 24-methyltetracontanol, 24,28-dimethyltetracontanol, 24,36-dimethyltetracontanol, and 24,28,36-trimethyltetracontanol. A fifth methyl-branched series was identified only in H. electellum, the internally branched trimethyl alcohols characterized by 22,26,30-trimethyltetracontanol. The incorporation of [3H]acetate and [1-14C]propionate into the internal lipids of mid-stage pupae (developing pharate adults) of H. electellum and H. virescens, showed that polar lipids, and VLMA and their acetate esters, were the major lipid classes synthesized from acetate. The major lipid classes synthesized from propionate, the precursor of the methyl branches, were the methyl-branched lipids, e.g., VLMA and their acetate esters and hydrocarbons. Aldehydes also were a component in H. virescens but did not incorporate radioactivity. The wax ester fraction of H. virescens incorporated radioactivity which was limited to the fatty acid moieties.

Cuticular lipid composition of Heliothis virescens and Helicoverpa zea pupae

The cuticular lipids of laboratory-reared tobacco budworms, Heliothis virescens (Fabricius), and corn earworms, Helicoverpa zea (Boddie), pupae were characterized. Quantities of cuticular lipid were greater for pupae in diapause than for non-diapausing pupae. Major cuticular lipids of H. virescens pupae were longchain n-alcohols (42%) and aldehydes (41%) with chain lengths of mainly C 26, C 28 and C 24 in decreasing order of abundance. Lesser amounts (2–5%) of wax esters and hydrocarbons were identified. The wax ester fraction was a complex mixture of C 32-C 52 components composed mainly of C 24-C 28 n-alcohol and saturated, monounsaturated and diunsaturated fatty acid (C 16-C 22) moieties. For H. zea, the major fractions were wax esters (38%), hydrocarbons (19%), n-alcohols (17%), diols (16%) and lesser amounts (2–5%) of aldehydes, acetate esters of alcohols and oxoalcohols. Triacontanyl hexadecanoate comprised 85% of the wax ester fraction. The H. zea alcohols, alcohol ester moieties and aldehydes consisted of a homologous series of C 32-C 52 compounds with the 30 carbon chain length as major constituents. The H. zea diols were C 30-C 36 even-chain n-alcohols with hydroxyl groups on carbon numbers 11, 12, 13, 14 or 15. Mass spectral analysis indicated the presence of unsaturation in the alkyl chain of the major diol components.

Effects of addition of clay minerals on the fatty acid fraction of a podzol soil

SummaryThe Al horizon of a sandy podzol soil, with a very small proportion of clay‐sized material, was sampled and homogenized. Samples, both with and without supplementation with 150 g clay minerals kg−1, natural heteroionic bentonite (saturated with Na, Ca, Mg, K), Mg‐bentonite or Fe‐kaolinite, were moistened to two‐thirds of water‐holding capacity and incubated at 28°C for 16 weeks.After incubation, lipids were extracted with 3:1 light petroleum: ethylacetate mixture in a Soxhlet apparatus as unbound components (directly extractable by organic solvents) and bound components (only extractable after treatment with acids). Monoacids (free and esterified), diacids, ketoacids and hydroxyacids were isolated from the two lipidic fractions (unbound and bound) by column chromatography. The different components of each family were analyzed by gas chromatography (GC) or gas chromatography‐mass spectrometry (GC‐MS).Incubation without supplementation generated a selective decrease in abundance of free mono‐acids in unbound and bound fractions. The decrease was in inverse proportion to the chain‐length of components. Soil supplementation with bentonite (homoionic or heteroionic) did not induce an overall quantitative change, but promoted a transfer of fatty acids from the unbound to the bound fraction, increased the exchange between free and esterified monoacids (transesterification) and stimulated hydrolysis of glycerides. In contrast, soil supplementation with Fe‐kaolinite caused much decomposition or biotransformation of monoacids but it did not induce change either in the intensity of transesterification in the wax ester fraction or in the intensity of hydrolysis in the glyceride fraction.

Characterization of wax esters in the roe oil of amber fish,Seriola aureovittata

AbstractThe wax esters of the roe oil of the amber fish,Seriola aureovittata, have been resolved by high‐performance liquid chromatography (HPLC) in the silver‐ion mode. Each of the fractions collected was transmethylated, and the fatty acids and alcohols were identified by gas chromatography/mass spectrometry (GC/MS) as the picolinyl esters and nicotinates, respectively. Their compositions were determined by GC. The fatty acid composition is complex, and the main components are C18:1n‐9 (35.5 mol%), C22:6n‐3 (20.3 mol%), and C16:1n‐7 (10.7 mol%), while fatty alcohols are limited to saturated (C16:0, 60.3 mol%; C18:0, 15.3 mol%; C14:0, 5.1 mol%) and monoenoic alcohols (C18:1n‐9, 6.5 mol%; C16:1n‐7, 4.5 mol%) with traces (&lt;0.1 mol%) of polyunsaturated fatty alcohols such as C20:3n‐3, C20:4n‐6, C20:5n‐3, and C22:5n‐3. Silver‐ion HPLC exhibited excellent resolution in which fractions were resolved on the basis of the number and configuration of double bonds as well as the distribution pattern between the acid and alcohol moieties of the molecules with a given number of double bonds. The main wax ester fraction are those of monoenoic acid‐saturated alcohol species, hexaenoic acid/saturated alcohol species, and pentaenoic acid/saturated alcohol species. Appreciable specificity was observed in the esterification of fatty acids with alcohols, and surprisingly, no saturated acid‐monoenoic alcohol species were detected.