Acetone Mobile Polar Lipids Research Articles

Lipid variations in tilapia (var. GIFT Oreochromis sp.) tissues due to dietary replacement of fish oil with camelina oil ( Camelina sativa )

Dietary fish oil can potentially be replaced by camelina oil in aquafeeds since 18:3n-3 (α-linolenic acid: ALA) accounts for 35% of the fatty acids. To test the effect of camelina oil on fish lipid composition, a feeding trial with tilapia (var. GIFT Oreochromis sp.) was carried out. Four experimental diets were formulated, one containing only fish oil (TFO), two where fish oil was replaced by camelina at low (Low-CO) and medium (Med-CO) levels, and another made only with camelina oil (TCO). A commercial diet (COM) was used as a reference diet. At the end of an 8-week feeding trial, the liver, kidney, heart and brain were sampled. In terms of proportions across tissues, the liver showed the highest triacylglycerol and oleic acid content; the kidney was higher in arachidonic (ARA) and eicosapentaenoic acid (EPA); the heart had the highest total lipids, linoleic acid (LOA) and ALA, while the brain was higher in sterols, acetone-mobile polar lipids (AMPL), phospholipids and docosahexaenoic acid (DHA). In terms of concentration among diets within tissues, when comparing TFO vs TCO, the phospholipids and ARA increased in the kidney, while the phospholipids decreased in the heart and the DHA in the brain. The TCO diet significantly increased 20:1n-9 and ALA in all analysed tissues. As expected, the COM diet significantly increased concentrations of EPA, docosapentaenoic acid (n-3DPA) and DHA in all analysed tissues.

Realistic exposure to fipronil, 2,4-D, vinasse and their mixtures impair larval amphibian physiology

Expansion of sugarcane crops may have contributed to the increased contamination of native habitats in Brazil. Several species of amphibians inhabit ponds formed in flooded farmlands, where pesticide concentrations are usually high. This study evaluated the ecotoxicological effects of the sugarcane pesticides fipronil and 2,4-D, as well as the fertilizer vinasse (isolated and mixed), on physiological responses of Leptodactylus fuscus and Lithobates catesbeianus tadpoles. In situ assays were conducted in mesocosms with concentrations based on the doses recommended by the manufacturer. Vinasse (1.3% dilution) caused 100% tadpoles’ mortality immediately after its application. Fipronil and/or 2,4-D altered antioxidant and biotransformation responses, induced neurotoxicity and changed lipid contents in tadpoles. A multivariate approach indicated that the mixture of pesticides induced most of the sublethal effects in both tadpole species, in addition to the isolated fipronil in L. fuscus. Fipronil alone increased glucose-6-phosphate dehydrogenase (G6PDH) activity, decreased acetylcholinesterase (AChE) and total lipid contents, and altered some individual lipid classes (e.g., free fatty acids and acetone-mobile polar lipids) in L. fuscus. The interaction between fipronil and 2,4-D in this species were more evident for lipid contents, although enzymatic alterations in G6PDH, AChE and glutathione-S-transferase (GST) were also observed. In L. catesbeianus, the mixture of pesticides reduced triglycerides and total lipids, as well as increased GST and decreased AChE activities. The detoxifying enzyme carboxylesterase was reduced by 2,4-D (alone or in mixture) in both species. Isolated pesticides also modulated specific lipid classes, suggesting their disruptive action on energy metabolism of tadpoles. Our study showed that fipronil, 2,4-D, and vinasse, individually or mixed, can be harmful to amphibians during their larval phase, causing mortality or impairing their functional responses.

Using multiple endpoints to assess the toxicity of cadmium and cobalt for chlorophycean Raphidocelis subcapitata

Metals may cause damage to the biota of contaminated environments. Moreover, using multiple endpoints in ecotoxicological studies is useful to better elucidate the mechanisms of toxicity of these compounds. Therefore, this study aimed to evaluate the effects of cadmium (Cd) and cobalt (Co) on growth, biochemical and photosynthetic parameters of the microalgae Raphidocelis subcapitata, through quantification of lipid classes composition, chlorophyll a (Chl a) content, maximum (ΦM) and effective (Φ’M) quantum yields and efficiency of the oxygen-evolving complex (OEC). Both metals affected the algal population growth, with an IC50–96h of 0.67 and 1.53 μM of Cd and Co, respectively. Moreover, the metals led to an increase in the total lipid content and reduced efficiency of OEC and ΦM. Cell density was the most sensitive endpoint to detect Cd toxicity after 96 h of treatment. Regarding Co, the photosynthetic parameters were the most affected and the total lipid content was the most sensitive endpoint as it was altered by the exposure to this metal in all concentrations. Cd led to increased contents of the lipid class wax esters (0.89 μM) and phospholipids (PL - at 0.89 and 1.11 μM) and decreased values of triglycerides (at 0.22 μM) and acetone-mobile polar lipids (AMPL - at 0.44 and 1.11 μM). The percentage of free fatty acids (FFA) and PL of microalgae exposed to Co increased, whereas AMPL decreased in all concentrations tested. We were able to detect differences between the toxicity mechanisms of each metal, especially how Co interferes in the microalgae at a biochemical level. Furthermore, to the best of our knowledge, this is the first study reporting Co effects in lipid classes of a freshwater Chlorophyceae. The damage caused by Cd and Co may reach higher trophic levels, causing potential damage to the aquatic communities as microalgae are primary producers and the base of the food chain.

Neutral and polar lipid fatty acids in five families of demersal and pelagic fish from the deep Northwest Atlantic

AbstractFatty acids in neutral and polar lipids were used to investigate trophic connections in species from five families of demersal (Rajella fyllae, Malacoraja senta, Alepocephalus bairdii, Borostomias antarcticus) and pelagic fish (Bathytroctes macrolepis, Lampanyctus spp., Chaulidos sloani, Serrivomer beanii) sampled in the deep Atlantic Ocean off Newfoundland, Canada. Lipid extracts were fractionated into neutral, acetone-mobile polar, and phospholipids to separate fatty acids in storage from those in membranes. Multivariate analysis of fatty acids showed that there were greater differences among the three lipid fractions than there were among the species when all fatty acid fractions were considered together. Neutral lipid fatty acids were characterized by monoenes, acetone-mobile polar lipids (AMPL) by C18 polyenes, and phospholipids by 16:0 and DHA. Multivariate analysis of fatty acids in phospholipids showed a strong grouping by taxonomic family (>80% similarity), while the neutral lipid fatty acids showed a weaker grouping by family (72.5% similarity) but groupings that also related to habitat and vertical migration. The neutral lipid data supported the use of 20:1ω9 as a biomarker of calanoid copepods and of 16:1ω7 as a marker of diatoms to determine food web connections in deep-sea fish, but not some other common markers. In addition, correlations with δ15N showed that series of ω6 and ω7 fatty acids were trophically transferred though neutral lipids, especially the essential fatty acid, ARA. Neutral lipids were also reservoirs for essential ω3 fatty acids in demersal species, but the major reservoir for DHA was AMPL and phospholipid in pelagic species.

Current lipid extraction methods are significantly enhanced adding a water treatment step in Chlorella protothecoides

Background Microalgae have the potential to rapidly accumulate lipids of high interest for the food, cosmetics, pharmaceutical and energy (e.g. biodiesel) industries. However, current lipid extraction methods show efficiency limitation and until now, extraction protocols have not been fully optimized for specific lipid compounds. The present study thus presents a novel lipid extraction method, consisting in the addition of a water treatment of biomass between the two-stage solvent extraction steps of current extraction methods. The resulting modified method not only enhances lipid extraction efficiency, but also yields a higher triacylglycerols (TAG) ratio, which is highly desirable for biodiesel production.ResultsModification of four existing methods using acetone, chloroform/methanol (Chl/Met), chloroform/methanol/H2O (Chl/Met/H2O) and dichloromethane/methanol (Dic/Met) showed respective lipid extraction yield enhancement of 72.3, 35.8, 60.3 and 60.9%. The modified acetone method resulted in the highest extraction yield, with 68.9 ± 0.2% DW total lipids. Extraction of TAG was particularly improved with the water treatment, especially for the Chl/Met/H2O and Dic/Met methods. The acetone method with the water treatment led to the highest extraction level of TAG with 73.7 ± 7.3 µg/mg DW, which is 130.8 ± 10.6% higher than the maximum value obtained for the four classical methods (31.9 ± 4.6 µg/mg DW). Interestingly, the water treatment preferentially improved the extraction of intracellular fractions, i.e. TAG, sterols, and free fatty acids, compared to the lipid fractions of the cell membranes, which are constituted of phospholipids (PL), acetone mobile polar lipids and hydrocarbons. Finally, from the 32 fatty acids analyzed for both neutral lipids (NL) and polar lipids (PL) fractions, it is clear that the water treatment greatly improves NL-to-PL ratio for the four standard methods assessed.ConclusionWater treatment of biomass after the first solvent extraction step helps the subsequent release of intracellular lipids in the second extraction step, thus improving the global lipids extraction yield. In addition, the water treatment positively modifies the intracellular lipid class ratios of the final extract, in which TAG ratio is significantly increased without changes in the fatty acids composition. The novel method thus provides an efficient way to improve lipid extraction yield of existing methods, as well as selectively favoring TAG, a lipid of the upmost interest for biodiesel production.

Improved separation and analysis of glycolipids by Iatroscan thin-layer chromatography–flame ionization detection

We demonstrate improved power of Iatroscan thin layer chromatography/flame ionization detection (TLC–FID) technique for analysis of complex marine lipid mixture by developing protocol for the separation and analysis of glycolipids including sulfoquinovosyldiacylglycerols (SQDG), monogalactosyldiacylglycerols (MGDG) and digalactosyldiacylglycerols (DGDG). We have modified the common protocol used so far for the analysis of lipid classes by replacing the elution step which uses pure acetone for the elution of acetone mobile polar lipids, with the elution step containing chloroform–acetone (72:28, v:v) for separation of MGDG and DGDG. To separate SQDG from the complex lipid matrix we introduced solvent mixture acetone–chloroform–methanol–formic acid (33:33:33:0.6, v:v:v:v). Quantification of glycolipid classes was performed after calibration with glycolipid standards for the masses between 0.2 and 2.7–5.0μg. With this new protocol we have successfully separated three glycolipids from the complex particulate lipid mixture of the seawater samples. Such an approach extends the power of existing protocol for the analysis of lipids which altogether ensure detection and quantification of 18 lipid classes what was demonstrated on seawater samples. This enables to gain a very broad system overview of the particularly complex environments as are seas, oceans and freshwaters.

Selected nutrient profiles in first larvae and postlarvae of American lobster (Homarus americanus)

Initiatives to enhance natural stock of lobster imply the production of high-quality postlarvae. The aim of this study was to evaluate the physiological condition of postlarvae produced under hatchery conditions by comparing the nutrient profiles of larvae stage I and postlarvae stage IV of American lobster (Homarus americanus) fed frozen adult Artemia with a mixture of dry commercial products. Body sterols, acetone mobile polar lipids and phospholipids levels were lower in stage IV than in stage I, while cholesterol was nearly 400 % higher in the former. The C20 mono-unsaturated acids and C22 n-3 decreased between stage I and IV in both neutral and polar lipids, while linoleic (18:2n-6 cis) and linolenic (18:3n-3) acids increased concomitantly. The levels of docosahexaenoic acid (DHA) in the polar fraction were twice lower in postlarvae compared to stage I larvae and almost completely depleted in the neutral fraction while eicosapentaenoic acid levels were reduced by nearly 30 % in the polar lipids and by over 70 % in the neutral lipids. Results suggested possible dietary phospholipids and DHA deficiencies that lead to the low levels observed in the postlarvae stage IV.

Growth and biochemical composition of Chlorella vulgaris in different growth media

The need for clean and low-cost algae production demands for investigations on algal physiological response under different growth conditions. In this research, we investigated the growth, biomass production and biochemical composition of Chlorella vulgaris using semi-continuous cultures employing three growth media (LC Oligo, Chu 10 and WC media). The highest cell density was obtained in LC Oligo, while the lowest in Chu medium. Chlorophyll a, carbohydrate and protein concentrations and yield were highest in Chu and LC Oligo media. Lipid class analysis showed that hydrocarbons (HC), sterol esthers (SE), free fatty acids (FFA), aliphatic alcohols (ALC), acetone mobile polar lipids (AMPL) and phospholipids (PL) concentrations and yields were highest in the Chu medium. Triglyceride (TAG) and sterol (ST) concentrations were highest in the LC Oligo medium. The results suggested that for cost effective cultivation, LC Oligo medium is the best choice among those studied, as it saved the cost of buying vitamins and EDTA associated with the other growth media, while at the same time resulted in the best growth performance and biomass production.

Effects of cadmium and nitrogen on lipid composition of Chlorella vulgaris (Trebouxiophyceae, Chlorophyta)

Investigations were carried out to evaluate lipid class and fatty acid composition of Chlorella vulgaris in relation to several combinations of cadmium (2 × 10−8; 10−7 M Cd) and nitrogen (2.9 × 10−6 to 1.1 × 10−3 M N) concentrations. Triacylglycerols (TAG), acetone mobile polar lipids (AMPL) and phospholipids (PL) were the major lipid classes of C. vulgaris under all the tested conditions. TAG was the lipid class accumulated in the highest amount in N-limited C. vulgaris. The AMPL lipid class was lowest at the lowest N and highest Cd treatment. High proportions of saturated fatty acids (SAFA) and monounsaturated fatty acids (MUFA) in the total lipid extracts were recorded under N limitation in the presence of Cd. 16:1(n-11) was an exception among the MUFA as its levels decreased at low N. Total polyunsaturated FA (PUFA), ω3 PUFA levels, and PUFA:SAFA ratios increased with increasing N concentrations, but when exposed to Cd, their levels were significantly reduced. Unlike the other PUFA, 18:2(n-6) increased with increasing N limitation. Significant negative relationships between TAG, MUFA and SAFA with N were recorded. Cd had a positive correlation with TAG, while N was with AMPL, PL and PUFA. In conclusion, a combination of N limitation and Cd stress significantly altered the lipid composition of C. vulgaris, and N limitation had the most significant overall effect on lipid class and fatty acid composition of the microalga.

Lipid composition of Chlorella vulgaris (Trebouxiophyceae) as a function of different cadmium and phosphate concentrations

Fatty acids are the fundamental structural components of membrane lipids, and the degree of saturation of the long hydrocarbon chains in microalgae contributes to regulation of growth, biomass production and reproduction of aquatic consumers. This research aimed at evaluating the effects of cadmium (2×10−8; 10−7molL−1Cd) on lipid class and fatty acid composition of the microalga Chlorella vulgaris under varying phosphate (PO43−) concentrations (6.0×10−7 to 2.3×10−4molL−1). Under PO43− limitation and Cd stress, the storage lipid class triacylglycerol (TAG) was the most accumulated among the lipid classes. Fatty acid composition revealed that the degree of saturation increased with increasing Cd stress and PO43− limitation. Decreasing PO43− and increasing Cd concentrations resulted in higher saturated fatty acid (SAFA) and monounsaturated FA (MUFA) concentrations. Total polyunsaturated FA (PUFA) and ω3 PUFA, and PUFA:SAFA ratios were higher in the control (2.3×10−4molL−1PO43−) cells than in either PO43− limitation or Cd stress, or in the combination of both stresses. Contrasting with all the other PUFAs, 18:2n – 6 increased as PO43− limitation increased. A significant positive relationship of PUFAs, acetone mobile polar lipids (AMPL) and phospholipids (PL) with phosphate concentration in the culture media was obtained, while TAG concentrations had a positive association with total MUFA and SAFA. Total SAFA, 14:0, 18:1n – 9 and 18:2n – 6 were positively correlated with Cd and negatively with PO43− concentrations. The microalga responded to combined PO43− limitation and Cd exposure by increasing its total lipid production and significantly altering its lipid composition. The FA 18:2n – 6 may be considered a stress biomarker for PO43− limitation and Cd stress in C. vulgaris.

Physical and biochemical properties of effluent leaving an onshore Atlantic cod (Gadus morhua, Linnaeus 1758; Gadiformes: Gadidae) aquaculture facility and potential use in integrated multi-trophic aquaculture

The physical and biochemical properties of Atlantic cod (Gadus morhua) wastes were analysed, and the waste remediation potential of blue mussels (Mytilus edulis) was assessed. Waste generated daily by Atlantic cod represented 24.9% of the cod feed added to the system. Particle distributions determined using a Coulter Multisizer and image analysis revealed that the majority of the particles in terms of numbers occupy the smaller size ranges; however, larger particles occupy a larger proportion of the volume. Effluent was composed of particles 500 μm (33%) by weight. The amount of dissolved carbon and nitrogen associated with the effluent represented 3.1% and 3.7%, respectively, of the total feed added to the system daily. Particles <70 μm had significantly less organic matter, lipids and fatty acids and were expected to be ingested more by mussels than larger particles. The major lipid classes present in effluent were free fatty acids, triacylglycerols, phospholipids, acetone mobile polar lipids and sterol. Cod effluent contained two essential fatty acids DHA and EPA, a diatom marker (16:1ω7), as well as two zooplankton markers 22:1ω11 and 20:1ω9, which accumulated in mussels and may serve as markers for aquaculture wastes. Although only 36% of the effluent was of a size suitable for mussel ingestion, this size fraction has the greatest potential to spread to surrounding areas. These particulates may be useful as an alternate food source when natural seston is low.

Lipid composition ofMytilus edulisreared on organic waste from aGadus morhuaaquaculture facility

The purpose of this study was to determine biochemical changes occurring in blue mussels (Mytilus edulis) fed effluent from an Atlantic cod (Gadus morhua) aquaculture facility over a period of ten weeks, compared to those in mussels fed a commercial shellfish diet and those supplied only filtered seawater. The total lipid and fatty acid content (mg g-1 wet weight) significantly decreased for mussels fed effluent during the experiment. The only change in the lipid class composition (% total lipid) at the end of the experiment was a significant increase in the proportion of acetone mobile polar lipids. There were several significant changes in the fatty acid composition (% total fatty acid) including an increase in the proportion of 18:1ω9, 18:2ω6, 20:4ω6, 21:5ω3 and the dienoic non-methylene-interrupted fatty acids 20:2a and 22:2b and significant decreases in the proportions of 16:0, 18:4ω3 and 20:5ω3. The increase in non-methylene interrupted dienes suggests that the amount of essential fatty acids in the effluent may be insufficient for optimal mussel growth. The presence of the terrestrial plant marker 18:2ω6 in both the fish feed and the effluent and its increased proportion in mussels fed effluent suggest that this fatty acid may have potential as a marker for aquaculture wastes.

FA determination in cold water marine samples.

The determination of FA in cold water marine samples is challenging because of the presence of large proportions of a variety of labile PUFA. This study was undertaken to establish optimal methods for FA analysis in various sample types present in the marine environment. Several techniques used in FA analysis, including lipid fractionation, FAME formation, and picolinyl ester synthesis, were examined. Neutral lipids, acetone-mobile polar lipids, and phospholipids (PL) were readily separated from each other on columns of activated silica gel, but recoveries of PL were reduced. Deactivation of the silica gel with 20% w/w water produced variable recoveries of PL (66 +/- 22%). FAME formation with BF3 gave optimal recoveries, and a method to remove hydrocarbon contamination from these samples before GC analysis using column chromatography was optimized. Picolinyl derivatives of FA are useful in structural determinations with MS, and a new base-catalyzed transesterification method of their synthesis from FAME was developed. Finally, a series of calculations, combining FA proportions with acyl lipid class concentrations, was designed to estimate FA concentrations. In algae and animal samples, these estimates were in good agreement with actual FA concentrations determined by internal standards.

Variation of lipid class and fatty acid composition of Chaetoceros muelleri and Isochrysis sp. grown in a semicontinuous system

The lipid class and the fatty acid composition of microalgae are of primary importance in feeding filter-feeding animals properly and variations of those parameters have never been investigated in a cultivation system applied to hatcheries. The objective of this study was to document the lipid class and fatty acid composition of the diatom Chaetoceros muelleri (CHGRA) and the flagellate Isochrysis sp. (Clone TISO) during the entire process of hatchery cultivation in relation to the period of the year (summer vs. winter). At the beginning of the cultivation process of CHGRA, in a small volume of culture, triacylglycerol (TAG), sterol, saturated, monounsaturated, and polyunsaturated fatty acids (particularly 20:5n3) were high, sharply dropping when volume was increased. An inverse relationship has been observed for acetone mobile polar lipids (AMPLs; pigment) and phospholipids (PLs), thus leading to no significant effect of the volume of culture on the total lipid (TL) content of CHGRA. The total lipid content of TISO increased with the volume of culture due to AMPL and PL classes and saturated and polyunsaturated fatty acids. The short- and long-term variability of lipid class composition has been observed for both species. Such results highlight the high variability of marine microalgae lipid content during the culture process and season as well. Hatchery implication is discussed. D 2003 Elsevier Science B.V. All rights reserved.

Lipid class and fatty acid composition of Pseudo-nitzschia multiseries and Pseudo-nitzschia pungens and effects of lipolytic enzyme deactivation

Lipid class and fatty acid compositions of stationary phase cultures of the toxic diatoms Pseudo-nitzschia multiseries and P. pungens were determined. The lipid class compositions of both diatoms were similar, with phospholipids, triacy1glycerols and acetone-mobile polar lipids as the major classes. Both pennate diatoms also displayed similar fatty acid compositions that were typical of diatoms, with high levels of 14:0, 16:1n-7, 16:2n-4 and 20:5n-3. In addition, elevated levels (>7%) of the fatty acid 16:4n-1 were found in both species and this fatty acid has potential as a signature compound in differentiating Pseudo-nitzschia species from other diatoms. The taxonomic similarities of the diatoms were apparent in the very similar lipid class and fatty acid compositions. Treatment of cells with boiling water was effective in deactivating lipolytic enzymes and resulted in a significant decrease ( P <0.05) in free fatty acids, a breakdown indicator and a general increase in polyunsaturated fatty acids in all samples. Thus, the routine use of boiling water to deactivate lipolytic enzymes in diatom samples is recommended.

Effects of light intensity, CO2 and nitrogen supply on lipid class composition of Dunaliella viridis

Lipid class composition of Dunaliella viridis Teodoresco was analysed using thin layer chromatography coupled with flame ionisation detection (TLC/FID technique). D. viridis was cultured under four different photon fluence rates and in darkness, and under two different conditions of CO2 supply (atmospheric and 1%) with and without nitrogen sufficiency. Nine lipid classes were identified and quantified. Total lipids per cell and acetone-mobile polar lipids decreased with light, while the percentage of sterols and triglycerides increased with increasing irradiance. Total phospholipids increase was related with growth rate while hydrocarbons, wax esters and sterol esters accumulated in darkness. There were almost no changes in total lipids per cell because of nitrogen limitation; however, nitrogen limitation led to higher changes in lipid class composition under 1% CO2 than under atmospheric CO2 levels. The main reserve lipid, triglycerides, accumulated in high amounts under 1% CO2 and nitrogen limitation, increasing from 1% to 22% of total lipids. The ratio sterols/acetone-mobile polar lipids could be an index of the 'light status' independently of nitrogen limitation, while the ratio triglycerides/total phospholipids could indicate any physiological stress uncoupling C and N metabolism and affecting the growth rate.

Lipid and lipid class content of the pelagic tunicate Oikopleura vanhoeffeni

Lipid biochemistry of pelagic tunicates is poorly known, despite the fact that the larvae of several flatfish species depend exclusively on oikopleurid appendicularians at time of first feeding. Microgravimetric analysis and thin- layer chromatography with flame ionization detection (TLC- FID) were used to determine the total lipid content and lipid class composition of the pelagic tunicate Oikopleura vanhoef- feni. Our goal was to determine the dominant storage form of lipid in 0. vanhoeffeni before and after the spring diatom bloom. Lipid levels and lipid class composition were measured for all 5 ontogenetic stages of 0, vanhoeffeni, plus eggs. Levels ranged from 23 to 525 ~g ind.-' over the entire life cycle, increasing exponentially with increasing body size and ontogenetic (i.e, maturity) stage. Regression analyses showed that 84 % of the variation in the logarithm of total lipid content was explained by the logarithm of ontogenetic stage. Per unit dry weight, the mean (f SE) lipid concentration was 5 f 0.3 % before the bloom and 7.5 f 1.2 % after the bloom. Lipid class composition provided scant evidence for energy storage by 0. vanhoeffeni, with no wax esters before or after the spring bloom and moderate levels of triacylglycerols present in pre- bloom animals only. Individuals collected after the spring bloom were significantly smaller than those from before the bloom, suggesting that a spawning event had occurred some- time during the bloom. Predominant lipid classes before and after the bloom were phospholipids (65 to 90 % of total lipid) and acetone-mobile polar lipids (4 to 24 '10). Thus, although this appendicularian is a suspension feeder inhabiting very cold water, it does not store wax esters as do high-latitude copepods. Rather, 0. vanhoeffeni has the lipid characteristics of a gelatinous, opportunistic colonist, i.e. that of an omnivore with the ability to direct ingested food energy into rapid somatic growth or gamete production.