Effect of Nitrogen Limitation on the Growth and Lipid Composition of the Green Alga <Emphasis Type="Italic">Botryococcus braunii</Emphasis> Kutz IPPAS H-252

The effect of nitrogen limitation in a medium on the composition of intracellular lipids in the alga Botryococcus braunii Kutz IPPAS H-252 in the course of culture development was investigated. Under the conditions of nitrogen limitation, the alga under investigation accumulated lipids as triacylglycerols, and this process was accompanied by substantial changes in the total fatty acid (FA) composition, which were manifested in a decrease in trienoic acids (from 52.8–57.2 to 19.5–24.7% of total FAs) and an increase in the content of oleic (from 1.1–1.2 to 17.1–24.4%) and saturated (from 23.7–26.0 to 32.9–46.1%) acids. In the control culture, the directionality of FA redistribution was less marked, and these changes were noticed at the later stages of culture development. Under nitrogen limitation, marked changes in the FA composition of polar lipids occurred by the 13th day, and they were characterized by an increase in the content of saturated acids (up to 76.8%) and a dramatic decrease in the content of all polyenoic acids (up to 6.8%). The changes in the FA composition of triacylglycerols were noticed as early as by the 7th day; these changes consisted in an increase in the content of oleic acid, and its high content (28.4–38.4%) was maintained up to the end of culturing. In the control culture, triacylglycerols with a high content of oleic acid were found by the 13th day, although, by this time, the content of total lipids and triacylglycerols did not change.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 357–365.Original Russian Text Copyright © 2005 by Zhila, Kalacheva, Volova.     

Lipids of the Green Alga BotryococcusCultured in a Batch Mode

The lipid fraction of the green alga Botryococcuscultured in a batch mode was found to contain polar lipids (more than 50% of the total lipids), di- and triacylglycerols, sterols and their esters, free fatty acids, and hydrocarbons. In aging culture, the content of polar lipids somewhat decreased and that of triacylglycerols increased by more than four times. The content of hydrocarbons in the algal biomass did not exceed 0.9% and depended little on the culture age. Intracellular lipids contained saturated and unsaturated (mono-, di-, and trienoic) fatty acids. The maximum content of C_{16 : 3}and -C_{18 : 3}fatty acids (up to 35% of the total fatty acids) was detected in the phase of active growth. The extracellular and intracellular lipids of the alga differed in the proportion of particular lipids and in the fatty acid pattern.     

Fatty acid composition of lipids in the calluses of two pine species <Emphasis Type="Italic">Pinus sibirica</Emphasis> and <Emphasis Type="Italic">Pinus sylvestris</Emphasis>

The fatty acid (FA) composition of callus lipids in two pine species, Pinus sibirica Du Tour and P. sylvestris L. was studied. Callus lipids were characterized by a high content of unsaturated FAs: 81.7% in P. sibirica and 63.2% in P. sylvestris. Among them, oleic and linoleic acids predominated (22.9 and 34.0% of total FAs in P. sibirica and 17.6 and 27.8% in P. sylvestris, respectively). Callus lipids also contained Δ5-UPIFA (unsaturated polymethyle-interrupted FAs), where pinoleic and sciadonic acids predominated. A comparison of FAs in the lipids of P. sylvestris calluses derived from needle and needle photosynthesizing tissues of this pine species showed that callus lipids were characterized by a greater diversity of Δ5-UPIFA but a lower degree of FA unsaturation and he higher level of Δ5-UPIFA.     

Fatty acid composition of lipids from mushrooms belonging to the family Boletaceae

The non-polar lipid content and fatty acid (FA) composition of 11 mushroom species of the family Boletaceae were determined. The non-polar lipid content ranged from 2.0 (Leccinum aurantiacum and Boletus erythropus) to 5.4 % (w/w) d.w. (Suillus grevillei) with an average value of 2.9 %. More than 25 different FAs were found in the mushroom lipids. Unsaturated FAs, mainly linoleic and oleic acids, accounted for about 83 % of the total FAs, while palmitic acid was the main saturated FA. Some FAs are identified for the first time in Boletaceae and in higher Basidiomycetes (cis-11,12-methyleneoctadecanoic acid, 7-cis,10-cis hexadecadienoic) or in fungi (cis-11,12-methyleneoctadecanoic acid). There were significant differences (P < 0.05) in the contents of specific FAs between mushroom species.     

Changes in the fatty acid composition of symbiotic dinoflagellates from the hermatypic coral <Emphasis Type="Italic">Echinopora lamellosa</Emphasis> during adaptation to the irradiance level

The composition of fatty acids (FAs) of symbiotic dinoflagellates isolated from the hermatypic coral Echinoporal lamellosa adapted to the irradiance of 95, 30, 8, and 2% PAR was studied. Polar lipids and triacylglycerols (TAG) differed between them in FA composition. Polar lipids were enriched in unsaturated FAs, whereas TAG, in saturated FAs. Light exerted a substantial influence on the FA composition in both polar lipids and TAG. The elevation of irradiance resulted in the accumulation of 16:0 acid in both lipid groups and 16:1(n-7) acid in TAG. It seems likely that de novo synthesis of 16:0 acid occurred actively in the cells of symbiotic dinoflagellates in high light. Since these processes are energy-consuming ones, they utilize excessive energy. When light intensity declined, 18:4(n-3) and 20:5(n-3) acids accumulated in polar lipids, which was accompanied by the increase in the content of chlorophyll a in the cells of zooxanthellae, whereas the levels of 22:6(n-3) and 20:4(n-6) acids reduced. Although the relative content of particular FAs varied substantially in dependence of irradiance, the balance between the sum of saturated and unsaturated FAs changed insignificantly. We concluded that the role of photoadaptation could not be limited only to changes in the degree of lipid unsaturation and membrane fluidity. It is supposed that light-induced changes in the FA composition reflect the interrelation between photosynthesis and FA biosynthesis.     

Effect of salinity on the biochemical composition of the alga <Emphasis Type="Italic">Botryococcus braunii</Emphasis> Kütz IPPAS H-252

The effect of 0.3 and 0.7 M NaCl on biomass yield, total nitrogen content, intracellular lipid content, and fatty acid profile of the lipids of the alga Botryococcus braunii IPPAS H-252 in different phases of the culture cycle was studied. The presence of sodium chloride in the medium inhibited the growth of algal cells for the first 3 days of the experiment, causing a decrease in total nitrogen, enhanced synthesis of triacylglycerols, and considerable changes in the lipid fatty acid profile: decreases in polyenoic acid contents (from 68.34% to 29.38% and 12.8%) and proportions of long-chain saturated acids (from 0.53% to 5.3% and 14.13% of the total fatty acids) at 0.3 M NaCl and 0.7 M NaCl, respectively. In later phases of the culture, at 0.3 M NaCl, the content of polyenoic acids rose to the values characteristic of the active growth phase of this alga. At 0.7 M NaCl, the proportion of polyenoic acids grew less significantly, but biomass concentration and total nitrogen increased, similarly to the experiment with 0.3 M NaCl.     

Fatty Acids from the Sea of Japan Sponge Halichondria panicea

The fatty acid (FA) composition of total lipids isolated from the marine sponge Halichondria panicea inhabiting Peter the Great Bay of the Sea of Japan was studied. GC and GC-MS techniques were used in identification of 63 FAs, with the main attention being paid to FAs with 14–22 carbon atoms. 4,8,12-Trimethyl-13:0 FA was for the first time identified as a main saturated FA, along with the branched FAs br-25:1, br-27:1, and br-27:2. The contents of arachidonic, eicosapentaenoic, docosapentaenoic, and the major demospongic acids [26:3(5,9,19), 26:3(5,9,17), 27:3(5,9,20), and 28:3(5,9,21)] considerably differed from those previously found for H. panicea, which may be due to seasonal changes in the species composition of organisms consumed by the sponge.     

Seasonal dynamics of fatty acid composition in female northern pike (Esox lucius L.)

Seasonal changes in the fatty acid composition of neutral and polar lipids were measured in the ovary, liver, white muscle, and adipopancreatic tissue of northern pike. The role of environmental and physiological factors underlying these changes was evaluated. From late summer (August–September) to winter (January–March), the weight percentage of n-3 polyunsaturated fatty acids (especially 22:6n3) declined significantly in the neutral lipids of all somatic tissues examined. However, large quantities of n-3 polyunsaturated fatty acids accumulated in the recrude cing ovaries during fall and the weight percentage of n-3 polyunsaturated fatty acids in ovary polar lipids also increased significantly. Additionally, the n-3 polyunsaturated fatty acid content of somatic polar lipids increased significantly during fall due to increases in the total polar lipid content of the somatic tissues. This suggests that during fall n-3 polyunsaturated fatty acid are diverted away from somatic neutral lipids and thereby conserved for use in ovary construction and for incorporation into tissue polar lipids. The percentage of n-3 polyunsaturated fatty acid in ovary neutral lipids also declined during fall and early winter, perhaps as an adaptation to conserve these fatty acids for storage in oocyte polar lipids and later incorporation into cellular membranes of the developing embryo. Reductions in the n-3 polyunsaturated fatty acids content of somatic and ovarian neutral lipids during fall were compensated for specifically by increases in the percentage of monounsaturated fatty acids rather than saturated fatty acids. This suggests that the ratio of saturated to unsaturated fatty acids in pike neutral lipid, is regulated physiologically, and hence may influence the physiological functioning of these lipids. During fall and early winter the percentage of saturated fatty acids declined significantly in the polar lipids of all tissues examined. This change was consistent with the known effects of cold acclimation on the fatty acid composition of cellular membranes. As the ovaries were recrudescing from September to January, liver polar lipids exhibited significant decreases in the percentage of total polyunsaturated fatty acids and n-3 polyunsaturated fatty acids and increases in monounsaturated fatty acids, and acquired a fatty acid composition very similar to that of ovary polar lipids. Therefore, seasonal changes in the percentage of polyunsaturated and monounsaturated fatty acids in liver polar lipids probably reflect the liver's role in vitellogenesis rather than the effects of temperature on membrane fatty acid composition. At all times of year, the fatty acid compositions of white muscle and adipopancreatic tissue neutral lipids were very similar, which may indicate a close metabolic relationship between these lipid compartments.Abbreviations AP adipopancreatic - BHT butylated hydroxytoluene - CI confidence interval - EFA essential fatty acids - MUFA monounsaturated fatty acids - NL neutral lipids - PL polar lipids - PUFA polyunsaturated fatty acids - SFA saturated fatty acids     

Lipid and fatty acid composition of the fat body during the female reproductive cycle of Labidura riparia (Insecta Dermaptera)

During the reproductive cycle of the female Labidura riparia, cytological observations show cyclical modifications of lipid droplets in the periovarian adipocyte. Fat body lipids and their constitutive fatty acids are analyzed. The lipids are predominantly triacylglycerols, which increase after adult ecdysis during vitellogenic and non-vitellogenic periods. Small amounts of diacylglycerols and phospholipids are found. Diacylglycerols increase during vitellogenesis and decrease during the non-vitellogenic period. Cytological modifications of lipid droplets are probably related to diacylglycerol fluctuations. Gas-liquid chromatography of fatty acid methyl esters shows oleic acid to be the predominant fatty acid in total lipids and triacylglycerols; unsaturated acids are approximately twice as abundant as saturated acids all along the reproductive cycle. Fatty acid composition of diacylglycerols and phospholipids differs from triacylglycerols and total lipids composition. Palmitic, stearic, oleic and linoleic acids represent the major fatty acids; their relative amounts vary during the different periods of the reproductive cycle. The correlations between fat body lipid changes and ovarian development were discussed and compared with observations made on other insect species. Accepted: 23 April 1997     

Specificity of Lipid Composition in Two Botryococcus Strains,the Producers of Liquid Hydrocarbons

The structure of liquid hydrocarbons and fatty acids produced by the green alga Botryococcus was identified. Two representatives of this alga, Botryococcus braunii Kütz, strain IPPAS H-252, introduced into culture earlier and an organism isolated for the first time from the Shira Lake, were used for this identification. Fatty acid composition of B. braunii, strain H-252, lipids was characterized by a high content of trienoic acids of C16–C18 series. The hydrocarbon composition of this strain was represented by straight-chain and branched-chain C14–C28 components; long-chain linear aliphatic C20–C27 hydrocarbons (54.4%) and 2,6,10,14-tetramethylhexadecane (20.5%) predominated among them. The strain H-252 differed in its fatty acid and hydrocarbon composition from the strains described earlier as Botryococcus braunii. The fatty acid composition of the Botryococcus isolate was represented mainly by C12–C32 saturated and monoenoic acids. The hydrocarbons formed by this isolate were represented by dienoic and trienoic components. C29 (48.9–56.3%) and C31 (11.1–16.3%) hydrocarbons predominated among the C23–C31 dienoic hydrocarbons, and C27, C29, and C31 trienoic hydrocarbons comprised 2.5–2.6% of total hydrocarbons. This type of hydrocarbons and the lipid fatty acid composition were characteristic for the race A of B. braunii.     

Fatty acids of sponges from the Sea of Okhotsk

The fatty acid (FA) composition of Demospongiae species from the Sea of Okhotsk was studied. Fifteen sponge species were investigated for the first time, and the previously studied species Desmacella rosea and Myxilla incrustans were reexamined for their FA composition. Gas chromatography-mass spectrometry revealed 150 different fatty acids, of which 15 have not been identified in sponge lipids previously. The relative content of saturated FAs varied from 7.6 in Melonachora kobjakovae to 29.6% in Amphilectus digitata, with an average of 14.6% of total FAs. The relative content of monoenic FAs ranged from 12.8 in T. dirhaphis to 27.0% in Polymastia sp., with an average of 20.6% of total FAs. Non-methylen-interrupted, primarily unsaturated Δ5,9-FAs contributed a significantly to the amount of polyunsaturated fatty acids of sponges; this being a distinguishing feature of the FA composition of the investigated group of organisms.     

Fatty Acid Composition of Lipids from Leaves and Strobila of Cycas Revoluta (<Emphasis Type="Italic">Cycas revoluta</Emphasis>)

Fatty acid (FA) composition of lipids from leaves and differentiated fleshy strobila tissues and sporangia with spores of Cycas (Cycas revoluta Thumb.) after their step quantitative extraction from plant material was investigated. Quantitative content and qualitative composition of FAs of extractable and nonextractable leaf lipids were determined. It was established that flesh lipids of sporophylls are characterized by a high saturation level and contain a considerable proportion of saturated FAs with the usual chain length (C₁₂–C₁₈, 53–57%). At the same time, total amount of etherified FAs with a very long chain in lipids not extractable by the method of Zhukov and Vereshchagin exceeds several times that found in extractable lipids (~15 and ~4%, respectively). Neutral lipids of Cycas spores were represented by triacylglycerols, the lower-alkyl esters of FAs, free FAs, and sterol esters.     

Characteristics of Lipid Fatty Acids in Calli of Two Geographic Populations of <Emphasis Type="Italic">Larix gmelinii</Emphasis>

The fatty acid (FA) composition of lipids of two geographic populations of larch (Larix gmelinii (Rupr.) Rupr.) was determined. One of these populations was grown on soil with a naturally high content of fluorides. This population exceeded the control one in the content of unsaturated fatty acids (FAs) in the lipid fraction of its calli. These FAs were characterized by the presence of 5-unsaturated FAs with irregular positions of double bonds, such as taxoleic, pinolenic, and sciadonic acids. It was established that the representatives of the larch fluoride population exceeded those of the control population in the content of these FAs in the total lipid fraction (8.1 and 6.7%, respectively).__________Translated from Fiziologiya Rastenii, Vol. 52, No. 3, 2005, pp. 343–348.Original Russian Text Copyright © 2005 by Makarenko, Konstantinov, Shmakov, Konenkina, Khotimchenko.     

Fatty acid composition of the blubber in white whales (Delphinapterus leucas)

Fatty acid (FA) composition of the blubber in free-ranging white whales (Delphinapterus leucas) from Svalbard's waters was determined and compared with the fatty acid composition of potential prey species in an attempt to assess diet. This methodology is based on the common assumption that unique arrays of FAs found within groups of organisms are transferred, largely unaltered, up marine food chains and thus may be useful for assessment of diet composition. Complete-column blubber biopsies were sampled from white whales (n=7) during the summers of 1996 and 1997. All captured animals were adult males. FAs were extracted from 2–4 replicates taken from an area about 10 cm in front of the mid-dorsal ridge. FA data from a total of 12 potential prey species from the Svalbard area were compared to the white-whale blubber samples. Twenty-two FAs were consistently found in relative amounts >0.5% of the total FA composition in white whales. These FAs accounted for 94–96% of the total FAs present. The blubber was composed almost entirely of triacylglycerols. The major saturated FAs were 14:0 and 16:0; 16:1(n-7), 18:1(n-9) and 20:1(n-9) were the major monounsaturated FAs and 20:5(n-3) and 22:6(n-3) were the major polyunsaturated FAs. Sixteen of the 22 FAs consistently found in the white-whale blubber were also found in considerable amounts (>0.5% of total FAs) in most of the potential species. Principal Component Analysis run on these 16 FAs suggests that polar cod (Boreogadus saida) had the most similar FA composition to the white-whale blubber, followed by capelin (Mallotus villosus), the copepod Calanus hyperboreus and the shrimp Pandalus borealis. Accepted: 27 November 1999     

Comparison of fatty acid composition in major lipid classes of the dominant benthic invertebrates of the Yenisei river

The composition and content of fatty acids (FAs) in total lipids, triacylglycerols (TAG) and polar lipids (PL) in dominant groups of benthic invertebrates: gammarids (Gammaridae, Amphipoda), chironomid larvae (Chironomidae, Diptera), caddisfly larvae (Trichoptera) and mayfly larvae (Ephemeroptera) were studied in the Yenisei river. For the first time data on the FA composition of species belonging to Trichoptera (Insecta) are presented. The groups of aquatic insect larvae and gammarids weakly differed in total content of essential polyunsaturated fatty acids (PUFAs). Hence, the strong invasion of gammarids which occurred in the last decades in the Yenisei river should not result in a decrease in potential yield of essential PUFA in the ecosystem and corresponding decrease in food resource quality for fish in respect to PUFA content. Significant differences in biomarker FAs in TAG were found which correlated to specific food sources. Different levels of long-chain PUFA in PL of the invertebrates are discussed in relation to the genetic ability of particular taxa to form these FAs.     

The Composition of fatty acids and aldehydes of the marine bryozoans <Emphasis Type="Italic">Berenicea meandrina</Emphasis> and <Emphasis Type="Italic">Dendrobeania flustroides</Emphasis> (Bryozoa: Gymnolaemata)

This study examines the composition of lipids, fatty acids, and fatty aldehydes in two marine bryozoan species, Berenicea meandrina and Dendrobeania flustroides, from the Sea of Okhotsk. The share of neutral lipids was up to 57.3% in D. flustroides and 54.9% in B. meandrina; the share of polar lipids was 33.2 and 40.4%, respectively. In all, 57 fatty acids (FA) and 9 aldehydes were identified in total lipids. The main FAs were 16:0, 18:0, 22:6n-3, and 20:5n-3. The content of branched saturated FA in bryozoans was on the average 6.4%. Three isomers of 16:1 (n-9, n-7, and n-5), five isomers of 18:1 (n-13, n-11, n-9, n-7, and n-5), four isomers of 20:1 (n-13, n-11, n-9, and n-7), as well as 22:1n-9 and 22:1n-13 were found; the presence of 7-methyl-6-hexadienoic acid (on the average, 3.0% of total FAs) was demonstrated. Non-methylene-inter-rupted FAs contributed 8.9 and 1.6% of the total FAs in D. flustroides and B. meandrina, respectively, and were identified as 20:2(5,11), 20:2(7,13), 20:3(5,11,14), 22:2(7,13), and 22:2(7,15). In B. meandrina, minor amounts of 24:0, 24:1, 25:0, 26:0, 24:4n-3, 26:3(5,9,19), and 28:3(5,9,19) were found, suggesting sponge biofouling on some bryozoan colonies. Aldehydes (branched saturated and unsaturated C_16–19 homologues) did not exceed 10.3 and 1.9% of the total FAs in D. flustroides and B. meandrina, respectively. The presence of the FA markers that are characteristic of microalgae, protozoans, and detritus in bryozoan lipids agrees well with data on polytrophic feeding of these bryozoans.     

Fatty acid composition of lipids from the vacuolar membranes of the roots of root vegetables

The fatty acid (FA) composition of vacuolar membrane lipids from the storage tissues of parsnip (Pastinaca sativa L.), parsley (Petroselinum crispum L.), and carrot (Daucus carota L.) was studied by gasliquid chromatography, and possible pathways of the biosynthesis of these acids are considered. A high level of unsaturated FAs (up to 78% of the total FA amount) was characteristic of these membrane lipids with the predominance of linoleic acid, which content in vacuolar lipids of parsnip, parsley, and carrot was 53.5, 55.1, and 54.4%, respectively. A high content of hexadienoic acid (C16:2ω6) was characteristic of the vacuolar lipids of parsnip and parsley (8.0 and 4.6%. respectively); the content of α-linolenic acid in the vacuolar lipids of these plants was 4.4–7.3%. Palmitic acid predominated among the saturated FAs (18.0–20.4%).     

A comparison of the metabolic fate of Fatty acids of different chain lengths in developing oilseeds

To determine if medium and long chain fatty acids can be appropriately metabolized by species that normally produce 16 and 18 carbon fatty acids, homogenates of developing Cuphea wrightii, Carthamus tinctorius, and Crambe abyssinica seeds were incubated with radiolabeled lauric, palmitic, oleic, and erucic acids. In all three species, acyl-CoA synthetase showed broad substrate specificity in synthesis of acyl-coenzyme A (CoA) from any of the fatty acids presented. In Carthamus, two- to fivefold less of the foreign FAs, lauric, and erucic acid was incorporated into acyl-CoAs than palmitic and oleic acid. Lauric and erucic acid also supported less glycerolipid synthesis in Carthamus than palmitic and oleic acid, but the rate of acyl-CoA synthesis did not control rate of glycerolipid synthesis. In all species examined, medium and long chain fatty acids were incorporated predominantly into triacylglycerols and were almost excluded from phospholipid synthesis, whereas palmitic and oleic acid were found predominantly in polar lipids. However, the rate of esterification of unusual fatty acids to triacylglycerol is slow in species that do not normally synthesize these acyl substrates.     

Lipid and hydrocarbon compositions of a collection strain and a wild sample of the green microalga Botryococcus

Lipid composition and hydrocarbon structure of two colonial green algae of the genus Botryococcus, i.e., a museum strain and a field sample collected for the first time from Lake Shira (Khakasia, Siberia), have been compared. Polar lipids, diacylglycerols, alcohols, triacylglycerols, sterols, sterol esters, free fatty acids and hydrocarbons have been identified among lipids in the laboratory culture. The dominant fraction in the museum strain was formed by polar lipids (up to 50% of the lipids) made up of fatty acids from C₁₂ to C₂₄. Palmitic, oleic, C₁₆ - C₁₈ dienoic and trienoic acids were the main fatty acids of the museum strain. Aliphatic hydrocarbons were found in the lipid of the museum strain. However, these amounted maximally to about 1% of the dry biomass at the end of exponential growth phase. The qualitative and quantitative compositions of FAs and hydrocarbons of the museum strain of Botryococcus, (registered at the Cambridge collection as Botryococcus braunii Kutz No LB 807/1 Droop 1950 H-252) differed from those of the Botryococcus strain described in the literature as Botryococcus braunii. The Botryococcus sp. found in Lake Shira is characterized by a higher lipid content (<40% of the dry weight). Polar lipids, sterols, triacylglycerols, free fatty acids and hydrocarbons have been identified among lipids in the field sample. The main lipids in this sample were dienes and trienes (hydrocarbons <60% of total lipid). Monounsaturated and very long chain monounsaturated fatty acids, including C_28:1 and C_32:1 acids, were identified in the Botryococcus found in Lake Shira. The chemo-taxonomic criteria allow us to unequivocally characterize the organism collected from Lake Shira as Botryococcus braunii, race A.     

Lipid composition of positively buoyant eggs of reef building corals

Lipid composition of the eggs of three reef building corals, Acropora millepora, A. tenuis and Montipora digitata, were determined. Sixty to 70% of the egg dry weight was lipid, which consisted of wax esters (69.5–81.8%), triacylglycerols (1.1–8.4%) and polar lipids c/mainly phospholipids (11.9–13.2%). Montipora digitata also contained some polar lipids typical of the thylakoid membrane in chloroplasts, probably due to the presence of symbiotic zooxanthellae in the eggs. The wax esters appeared to be the major contributor to positive buoyancy of the eggs, and specific gravity of wax esters in A. millepora was estimated to be 0.92. Among the fatty acids of the wax esters, 34.9–51.3% was hexadecanoic acid (16:0) while the major fatty acids in polar lipids were octadecenoic acid (18:1), hexadecanoic acid (16:0), eicosapentaenoic acid (20:5) and eicosatetraenoic acid (20:4). The wax ester appears to be the main component of the 4.5 6.0 m diameter lipid droplets which fill most of the central mass of the coral eggs.