Lipid composition of copepodite stages and adult females of Calanus glacialis in Arctic waters of the Barents Sea

Summary The composition of lipid classes and their component fatty acid are described for copepodite stages III, IV, V, and adult females of Calanus glacialis sampled from Arctic waters of the Barents Sea during summer. Was esters were the principal component of the lipid in all copepodite stages examined, averaging 73% over all the stages. The proportion of triacylglycerols varied from 1.5% to 10.5% of total lipid among copepodite stages. The lipids of adult females contained lower levels of wax esters and higher levels of triacylglycerols than copepodite stages III, IV and V. Fatty alcohols of wax esters from copepods sampled in June and July were dominated by 20:1 (n-9) and 22:1 (n-11) alcohols with the proportion of 20:1 (n-9) increasing from stages III to adult female. 14:0 and 16:0 alcohols were the principal fatty alcohols of wax esters of a sample comprising mainly of copepodites stage III taken in August. 16:1 (n-7), 20:1 (n-9) and 20:5 (n-3) were the major fatty acids in the was esters of animals captured in June and July whereas 18:1 (n-9) predominated in the August sample. The polar lipids of the copepodite stage III from August also contained lower levels of polyunsaturated fatty acids than from all stages of copepods from June and July. The data are discussed in relation to life cycle strategies and trophic aspects of Calanus glacialis in the Arctic pelagic community of the Barents Sea.     

Lipids and trophic interactions of ice fauna and pelagic zooplankton in the marginal ice zone of the Barents Sea

Gammarus wilkitzkii, Apherusa glacialis, Onismus nanseni, Onismus glacialis, Boreogadus saida, Parathemisto libellula and Calanus hyperboreus, collected in late June in the Barents Sea marginal ice zone, contained substantial levels (28–51% of the dry mass) of total lipid, the highest levels (51% and 41% respectively) being in  A. glacialis and  C. hyperboreus. Neutral lipids were present in greater amounts than polar lipids in all species. Triacylglycerols were major neutral lipids in A. glacialis, G. wilkitzkii and O. nanseni; triacylglycerols and wax esters were present in similar amounts in O. glacialis; higher levels of wax esters than triacylglycerols occurred in P. libellula; wax esters greatly exceeded triacylglycerols in C. hyperboreus, the opposite being true for B. saida. Diatom fatty acid markers were prominent in the triacylglycerols of G. wilkitzkii, O. nanseni, O. glacialis and, particularly, of  A. glacialis; 20:1(n-9) and 22:1(n-11) moieties were abundant in wax esters of G. wilkitzkii, O. nanseni, O. glacialis, P. libellula and  C. hyperboreus, and in triacylglycerols of B. saida. We deduce that  A. glacialis feeds mainly on ice algae and phytodetritus, G. wilkitzkii and the Onismus spp. feed on calanoid copepods as well as ice algae, whereas P. libellula and especially B. saida feed extensively on calanoid copepods. Accepted: 17 May 1998     

The lipid biochemistry of calanoid copepods

Calanus species, particularly those in high latitudes, can accumulate large oil reserves consisting predominantly of wax esters. These wax esters consist predominantly of 16:0, 20:1 (n–9) and 22:1 (n–11) fatty alcohols, mainly formed de novo by the animals from non-lipid dietary precursors, esterified with various fatty acids that are often polyunsaturated fatty acids and largely of dietary, phytoplanktonic origin. Wax ester formation is maximal in copepodite stages IV and V. The lipids are elaborated not primarily for buoyancy regulation but as a source of metabolic energy during overwintering, particularly for reproduction. Large quantities of wax esters are utilised for gonadal development when stage V copepodites mature to females. Development of stage V copepodites to males is not accompanied by wax ester utilisation but males consume large amounts of these lipids in physical activity during reproduction. The role of wax esters in the life history of calanoids is illustrated with particular reference to a comparison of Calanus finmarchicus and Metridia longa in Balsfjord, northern Norway.     

Assimilation and biosynthesis of lipids in Arctic Calanus species based on feeding experiments with a C labelled diatom

The dominant Arctic Ocean and North Atlantic copepods Calanus hyperboreus, Calanus glacialis, and Calanus finmarchicus were collected in the Greenland Sea and fed ¹³C labelled diatom Thalassiosira weissflogii to follow the transfer and assimilation of carbon, lipid, and individual fatty acids and alcohols. The diatom was grown with ¹³C for 3 to 5 days and fed then to the copepods. During the feeding period of 14 days, total carbon increased in the copepodite stages V of C. hyperboreus and C. finmarchicus, whereas carbon remained almost constant in C. glacialis females. However, total lipid increased in all species and stages. Highest lipid accumulation occurred in C. hyperboreus in which nearly all lipids were exchanged already after 11 days of feeding. In the other species lipid accumulation made up between 22% (C. finmarchicus) and 45% of total lipid (C. glacialis). The proportion of wax esters was high ranging from 76% of total lipid in C. glacialis to 92% in C. finmarchicus. The fatty acid composition of the alga was dominated by 16:1(n-7), 16:0, 20:5(n-3), and 22:6(n-3). The composition of the copepods was similar because of feeding already on diatoms in the field. In addition, the monounsaturated fatty acids and alcohols, 20:1(n-9) and 22:1(n-11), were major components of the copepod lipids. During the feeding period the highest ¹³C labelling was always found in the C₁₆ polyunsaturated fatty acids and in the 16:1(n-7) alcohol. Because these components occurred only in trace amounts in the copepods they totally originated from the diet explaining the high labelling. It is noteworthy that the 16:1(n-7) alcohol originated only from the corresponding dietary and not from the abundant internal fatty acid. The long-chain monounsaturated fatty acids and alcohols, 20:1(n-9) and 22:1(n-11), are not existent in phytoplankton and have to be produced de novo. They were less labelled in the smaller species but highly ¹³C enriched in C. hyperboreus. Although dietary fatty acids were generally retained by the copepods it seems that fatty acids or even lipids were selectively accumulated and turned over due to bodily requirements, and thus, essential polyunsaturated fatty acids were preferentially retained. During feeding mixing, accumulation, and exchange of internal and dietary fatty acids and alcohols occurred as well as utilisation of lipids from both sources for metabolic requirements. The differences in lipid assimilation fit to the different life strategies of the copepods.     

Lipid composition of zooplankton in relation to the sub-arctic food web

Summary Seasonal changes in the lipid class composition and fatty acid and fatty alcohol composition of neutral lipids were determined for Calanus finmarchicus, Metridia longa and Sagitta sp. in Balsfjord, northern Norway. Similar analyses were obtained for C. hyperboreus and Parathemisto abyssorum in an adjacent fjord, Ullsfjord, in spring. C. finmarchicus, C. hyperboreus, M. longa, and Parathemisto abyssorum all contained large amounts of wax esters whereas Sagitta sp. contained small amounts of triacylglycerols and traces of wax esters. the levels of wax ester in C. finmarchicus and M. longa were highest in late autumn (respectively 88% and 84% of total lipid) and lowest in early spring (respectively 85% and 27% of total lipid). The accumulation of these neutral lipids in spring and summer is related to the feeding activity during the primary production period, while their decline in late winter is associated with the mobilisation of metabolic energy for production of gonads. The major fatty alcohols in the wax esters of C. finmarchicus and C. hyperboreus and Parathemisto abyssorum were 20:1 and 22:1 while those in the wax esters of M. longa were 14:0 and 16:0. The traces of wax esters in Saqitta were rich in 20:1 and 22:1 fatty alcohols. These analyses are consistent with C. finmarchicus and C. hyperboreus being strictly herbivorous, M. longa being more carnivorous and both Sagitta sp. and Parathemisto being highly carnivorous, probably ingesting substantial amounts of calanoid copepods.     

The lipid compositions of high-Antarctic notothenioid fish species with different life strategies

Lipid and fatty acid compositions of five notothenioid fishes from the Antarctic Weddell and Lazarev Seas were investigated in detail with regard to their different modes of life. The pelagic Aethotaxis mitopteryx was the lipid-richest species (mean of 61.4% of dry mass, DM) followed by Pleuragramma antarcticum (37.7%DM). The benthopelagic Trematomus lepidorhinus had an intermediate lipid content of 23.2%DM. The benthic Bathydraco marri (20.8%DM) and Dolloidraco longedorsalis (14.5%DM) belonged to the lipid-poorer species. Triacylglycerols were the major lipid class in all species. Important fatty acids were 16:0, 16:1(n-7), 18:1(n-9), 18:1(n-7), 20:5(n-3) and 22:6(n-3). The enhanced proportions of the long-chain monounsaturated fatty acids, 20:1 and 22:1, in the lipid-rich pelagic fishes clearly reflected the ingestion of the two copepod species, Calanoides acutus and Calanus propinquus, which are the only known Antarctic zooplankters rich in these fatty acids. Although wax esters are the major storage lipid in many prey species, they were absent in all notothenioid fishes studied. Thus, wax esters ingested with prey are probably converted to triacylglycerols via fatty acids or metabolised by the fishes. The enhanced lipid accumulation with increasingly pelagic lifestyle has energetic advantages, especially with regard to improved buoyancy. It is still unknown to what extent these lipids are utilised as energy reserves, since it has been suggested that not only the benthic but also the pelagic Antarctic fishes are rather sluggish, with a low scope for activity and hence low metabolic requirements. Accepted: 14 May 2000     

A Comparison of the Composition of Wax Ester Molecular Species of Different Coral Groups (Subclasses Hexacorallia and Octocorallia)

Wax esters, which are esters of fatty alcohols and fatty acids (FAs), are one of the main classes of reserve lipids in all coral species. The chemical structures and the content of wax ester molecular species were determined for the first time in nine coral species from three taxonomic groups: symbiotic reef-building corals, (Hexacorallia subclasses), symbiotic soft coral alcyonarians, and asymbiotic soft coral gorgonians (Octocorallia subclasses) collected in the South China Sea (Vietnam). Our comparison of these groups showed that the absence of symbiotic microalgae (zooxanthellae) and the exoskeleton affects the profile of molecular species of wax esters considerably. The main components of wax esters of all corals were cetyl palmitate (16:0-16:0) and other saturated wax esters containing 30, 34, and 36 carbon atoms. The content of unsaturated molecular species 6:0–16:1, 16:0–18:1, and 16:0–20:1 in wax esters of symbiotic soft corals (alcyonarians) was greater than that in wax esters of reef-building corals. In contrast to symbiotic coral species, wax esters of asymbiotic soft corals, namely azooxanthellate gorgonians, contained a considerable amount of long-chain molecular species (C₃₇-C₄₁) with an odd number of carbon atoms. The presence of such molecular species indicates that asymbiotic gorgonians may use bacterial FAs in biosynthesis of their own wax esters. This observation confirms our hypothesis that bacterial community is important for maintaining the energy balance of azooxanthellate corals.     

Vertical distribution and dietary preferences of deep-sea copepods (Euchaetidae and Aetideidae; Calanoida) in the vicinity of the Antarctic Polar Front

Four Paraeuchaeta species and three aetideids were frequently encountered along 51°30′S in the Atlantic sector of the Southern Ocean. Paraeuchaeta antarctica was most abundant close to the Antarctic Polar Front. Within the genera Paraeuchaeta and Gaetanus, congeners usually partitioned the water column. Euchaetidae had high lipid (≤37% dry mass, DM in adult females) and wax ester contents (≤22% DM). Fatty acid composition of Paraeuchaeta spp. was dominated by monounsaturated moieties, especially 16:1(n-7) and 18:1(n-9), while fatty alcohols were mainly saturated. Surprisingly, only the bathypelagic P. barbata contained moderate amounts of 20:1(n-9) and 22:1(n-11) fatty acids (≤14%) and high levels of the respective fatty alcohols (≤50%), generally considered trophic biomarkers for calanid copepods as prey. Thus, herbivorous calanid copepods seem to be a readily available prey source at bathypelagic depths, indicating that their seasonal vertical migration provides a “trophic shortcut” from primary production at the surface to the interior of the ocean. Aetideidae also contained substantial levels of total lipid (14–36% DM), but wax esters contributed only up to 12% DM in copepodite stages C5 of Gaetanus spp., whereas other stages of Gaetanus and Aetideopsis minor only contained ≤6% DM of wax esters. The fatty acid compositions of Aetideidae were more balanced with 16:0, 18:1(n-9), 20:5(n-3), and 22:6(n-3) as important components, indicating a generally omnivorous feeding behaviour.     

Nature,origin and possible roles of lipid deposits in Maurolicus muelleri (Gmelin) and Benthosema glaciale (Reinhart) from Ullsfjorden,northern Norway

Summary The lipid-rich pelagic teleost Maurolicus muelleri has large lipid depots located subcutaneously, intramuscularly and around the digestive tract. The lipid is contained within conventional adipocytes and is composed largely of triacylglycerols rich in 20:1 (n-9) and lipid-rich mesopelagic teleost Benthosema glaciale, except that the lipid is predominantly wax esters whose fatty alcohols and fatty acids are both rich in 20:1 (n-9) and 22:1 (n-11) moieties. An origin for the lipids of both species in the wax esters of calanoid copepods is indicated. The anatomical distribution of the lipids in these teleosts and their intracellular location point to their being fundamentally an energy store. The twin roles of neutral lipids in providing metabolic energy and buoyancy are discussed.     

Functional biodiversity of lipids in Antarctic zooplankton: Calanoides acutus, Calanus propinquus, Thysanoessa macrura and Euphausia crystallorophias

Zooplankton samples were collected in January 1993 off Dronning Maud Land along a transect from open waters to the marginal ice zone close to the Antarctic ice shelf. Thysanoessa macrura was caught in open waters while Calanoides acutus and Calanus propinquus were mainly sampled between ice floes in the marginal ice zone. The “ice-krill”Euphausia crystallorophias was found over the shelf directly associated with ice floes. T. macrura had a lipid content up to 36% of its dry weight with the dominant lipid class, wax ester, accounting for 45–50% of the total lipid. The predominance of 18:1 fatty alcohols is the striking characteristic of the wax esters. Small specimens of E. crystallorophias had lipid levels up to 26% of their dry weight with, unexpectedly, triacylglycerols being the dominant lipid (up to 41% of total lipid). The small levels of wax esters in these animals (3–6% of total lipid) had phytol as a major constituent. Large specimens of E. crystallorophias had up to 34% of their dry weight as lipid, with wax esters (47% of total lipid) dominated by 16:0 and 14:0 fatty alcohols as the major lipid. Calanus propinquus had lipid levels of up to 34% of their dry weight, with triacylglycerols (up to 63% of total lipid) being the dominant lipid. High levels of 22:1 (n-9) fatty acid were present in the triacylglycerols. Calanoides acutus had lipid levels up to 35% of the dry weight with wax esters accounting for up to 83% of total lipid. High levels of (n-3) polyunsaturated fatty acids were recorded with 20:5(n-3), 22:6(n-3) and 18:4(n-3) being the dominant moieties. On the basis of their lipid compositions we deduce that: (1) Calanoides acutus is the strictest herbivore among the four species studied, heavily utilizing the typical spring bloom; (2) T. macrura is essentially omnivorous, probably utilizing the less defined bloom situations found in oceanic waters; (3) E. crystallorophias is an omnivore well adapted to utilize both a bloom situation and to feed on ice algae and micro-zooplankton associated with the ice; (4) Calanus propinquus seems to be the most opportunistic feeder of the four species studied, probably grazing heavily on phytoplankton during a bloom and, during the rest of the year, feeding on whatever material is available, including particulates, flagellates and other ice-associated algae. We conclude that the different biochemical pathways generating large oil reserves of different compositions, enabling species to utilize different ecological niches, are major determinants of biodiversity in polar zooplankton. Accepted: 22 June 1998     

Waxes and lipids associated with the external waxy structures of nymphs and pupae of the giant whitefly, Aleurodicus dugesii

The nymphs and pupae of the giant whitefly, Aleurodicus dugesii, produce large quantities of external lipids, both as waxy particles and as waxy filaments. The nymphs and pupae extrude filaments from two dorsal rows of five pores each. Filaments can attain lengths of 5-8 cm. The external lipids of nymphs and pupae consist largely of long-chain aldehydes, alcohols, acetate esters and wax esters. Hydrocarbons are minor components. Soon after hatching, the nymph produced an unidentified waxy fringe extruded laterally from its margin. After molting to the second instar, long, hollow, waxy filaments were produced by the immature stages. The major lipid class associated with the filaments was saturated wax esters (89%), mainly C44, C46 and C60. Associated with formation of the filaments were waxy particles in the shape of curls, which peeled off of the extruding filaments. Similar but more tubular-shaped curls were also produced by numerous lateral pores so that, eventually, the curls completely camouflaged the nymph. The major lipid class of the curls was wax esters (50%), mainly C44 and C46. The cuticular surface lipids of the nymphs were mainly long-chain aldehydes (43%) and wax esters (27%). Unsaturated fatty acid moieties constituted 2 and 19% of the wax esters of curls and nymph cuticular surface lipids, respectively. The major lipid classes of pupae and of their palisade were long-chain aldehydes and alcohols. No unsaturated wax esters were detected in the filaments, but 30% of pupal and 21% of palisade surface wax esters were unsaturated in their fatty acid moieties, 16:1, 18:1 and 20:1.     

Understanding the trophic role of the Antarctic ctenophore,Callianira antarctica,using lipid biomarkers

To better understand the trophic role of ctenophores in Antarctica during austral fall and winter, a major species of cydippid ctenophore, Callianira antarctica, was collected during April/May (fall) and August/September (winter) 2002 in the vicinity of Marguerite Bay. Lipid content, lipid classes, fatty acids, fatty alcohols and sterols were analyzed in animals, together with lipid biomarkers in krill and copepod species representing potential ctenophore prey. Lipid content in ctenophores collected in winter was slightly higher than from animals in fall (4.8 and 3.5% of dry weight, respectively). Polar lipids were the dominant lipid class in ctenophores, accounting for over half of the lipid content, with significant amounts of free fatty alcohols (more than 10% of total lipid content) detected. Lipid-class composition, however, differed significantly between seasons, with significant amounts of neutral lipid (wax esters and triacylglycerols) only detected in animals from fall. Although the dominant lipid classes in ctenophores varied between fall and winter, individual lipids (i.e., fatty acids, alcohols and sterols) showed only minor changes between seasons. Specifically, long-chain polyunsaturated fatty acids [20:5(n-3) and 22:6(n-3)] found in high abundance in larval krill were also elevated in ctenophores collected in winter. Very high amounts of monounsaturated fatty alcohols, particularly 20:1(n-9) and 22:1(n-11), known to be important components of wax esters in calanoid copepods, were also observed. Multivariate analysis using the suite of lipids found indicated that copepods are an important diet item for ctenophores in the study area. Results further suggest that C. antarctica feed actively year-round, with larval krill providing a food resource during austral winter.     

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.     

Lipid composition of the three co-existing <Emphasis Type="Italic">Calanus</Emphasis> species in the Arctic: impact of season,location and environment

Arctic species of Calanus are critical to energy transfer between higher and lower trophic levels and their relative abundance, and lipid content is influenced by the alternation of cold and warm years. All three species of Calanus were collected during different periods in Kongsfjorden (Svalbard, 79°N) and adjacent shelf during the abnormally warm year of 2006. Lipid composition and fatty acid structure of individual lipid classes were examined in relation with population structure. Wax esters dominated the neutral lipid fraction. Phosphatidylcholine (PC) dominated the structural lipids followed by phosphatidylethanolamine (PE). PC/PE ratios of 3–6 suggested an increase in PC proportions compared to earlier studies. Depending on the time scale, fatty acids of wax esters illustrated either trophic differences between fjord and offshore conditions for C. hyperboreus and C. finmarchicus or trophic differences related to seasonality for C. glacialis. Similarly, seasonality and trophic conditions controlled the changes in fatty acids of triglycerides, but de novo synthesis of long-chain monoenes suggested energy optimization to cope with immediate metabolic needs. Polar lipids fatty acid composition was species specific and on the long-term (comparison with data from the past decade) composition appears related to changes in trophic environment. Fatty acid composition of PC and PE indicated relative dominance of 20:5n-3 in PC and 22:6n-3 in PE for all three species. The combination of PE and PC acyl chain and phospholipid head group restructuring indicates an inter-annual variability and suggests that membrane lipids are the most likely candidate to evaluate adaptive changes in Arctic copepods to hydrothermal regime.     

Effects of the season and growth stage on the contents of lipids and photosynthetic pigments in brown alga <Emphasis Type="Italic">Undaria pinnatifida</Emphasis>

Seasonal changes in the contents of lipids and photosynthetic pigments (PSP) in the brown alga Undaria pinnatifida (Harvey) Suringar (Phaeophyceae, Alariaceae) on different stages of its growth were studied. Lipids of all plant growth group comprised glyceroglycolipids (GL), phospholipids, and neutral lipids (NL). The ratio between these lipid groups and the content of particular lipids depended on the season and algal growth stage: NL predominated in seedlings; juvenile algae comprised approximately similar amounts of NL and GL; and in adult algae, GL predominated. In winter and spring, algal tissues contained relatively more free sterols than in summer. Total lipid content in seedlings and juvenile algae was higher then in adult plants. Lipid fatty acid (FA) composition was similar on all growth stages, but the content of major components differed; this is mainly related to 18:4 n-3, 20:4 n-6, and 20:5 n-3 acids. The predominant FAs in seedling lipids were saturated FAs, whereas in the lipids of juvenile and adult algae, polyunsaturated FAs predominated.     

The surface wax composition of the exuviae and adults of Aleyrodes singularis

Long-chain aldehydes, alcohols, hydrocarbons and wax esters were major components of the external lipids of adult Aleyrodes singularis. In exuviae, acetate esters replaced the hydrocarbons as a major component. The major long-chain alcohol and aldehyde from adults were C32 and were essentially the exclusive components of the wax particles. The major alcohol from exuviae was C26 and the aldehydes were C26, C28, C30 and C32. The major acetate esters were C28 and C30 in both adults and exuviae. There were wax esters of similar carbon number in adults and exuviae although the exuviae had a greater amount of wax esters with unsaturated fatty acids. The fatty acid and alcohol composition of the wax esters differed markedly between adults and exuviae. Wax esters of adults had similar amounts of C16, C18, C20, C22 and C24 fatty acids while those from exuviae contained largely C16 and C18. The major alcohol in the wax esters of adults was C22 and those of exuviae were C26 and C28. The distribution of fatty acids and alcohols among wax esters of varying chain length also differed between adults and exuviae: in adults C22 was the major fatty acid found in the dominant wax ester, C44 and the C22 alcohol was the major alcohol and found in wax esters C42 and C44. In exuviae C16 and C18 were the major fatty acids found in most wax esters and a C28 alcohol was the major alcohol found in wax esters C44 and C46, the two dominant wax esters in exuviae. It was clear that the difference in chemistry of the wax esters between the adults and exuviae is not evident unless the acid and alcohol moieties are characterized.     

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.     

Aliphatic Chains of Esterified Lipids in Isolated Eyespots of Euglena gracilis var. bacillaris

Isolated eyespot granules of Euglena gracilis Klebs var. bacillaris Pringsheim contained approximately 6% lipids (based on protein). Separation of the lipid extracts by thin layer chromatography revealed four major fractions: wax esters, triacylglycerols, free fatty acids, and phospholipids. Methanolysis of each fraction yielded between 27 and 29 different fatty acids ranging from 12:0 to 22:6. Acetates of the fatty alcohols of the wax fraction consisted of 11:0 to 18:0 carbon chains, with 14:0 being the major component; unsaturated alcohols were not detected.     

Lipid storage compounds in marine bacteria

Forty psychrophile or psychrotrophic crude-oil-utilizing marine bacteria were investigated for their ability to accumulate lipid storage compounds in the cytoplasm during cultivation under nitrogen-limiting conditions. Most of them (73%) were able to accumulate specialized lipids like polyhydroxyalkanoic acids (PHA) while other lipids such as wax esters occurred in two isolates. Accumulation of PHA occurred predominantly at low temperatures (4–20 °C) as demonstrated for three isolates. Electron microscopy revealed polyphosphate inclusions occurring in two isolates in addition to PHA. Cells of the isolate Acinetobacter sp. 211 were able to synthesize and accumulate lipid inclusions during growth on acetate, ethanol, olive oil, hexadecanol and heptadecane. The composition of the lipid inclusions depended on the compounds provided as carbon source. Wax esters and acylglycerols occurred mainly during the cultivation on olive oil; in contrast, wax esters and free alcohols occurred during cultivation on hexadecanol. Total fatty acids in cells of the Acinetobacter sp. 211 amounted to 25% of the cellular dry weight in olive-oil-grown cells. Palmitic acid was the main fatty acid in the lipids when the cells were cultivated on acetate or ethanol (44% and 32% of total fatty acids respectively). In contrast, fatty acids occurring in the lipids during cultivation on hexadecanol, heptadecane or olive oil were related to the carbon source. The fatty acids present in the accumulated lipids consisted predominantly of saturated and unsaturated straight-chain fatty acids with a chain length ranging from 12 to 18 carbon atoms. Analysis of the lipid-granule-associated proteins in cells of Acinetobacter sp. 211 revealed a protein of 39 kDa as the predominant protein species. Received: 2 July 1996 / Received revision: 3 September 1996 / Accepted: 28 September 1996     

Synthesis of lipids from acetate by human preputial and abdominal skin in vitro

Lipogenesis in vitro from acetate-1-(14)C was studied in human preputial skin and abdominal skin. Radioactive lipids were separated by column chromatography on Florisil and by thin-layer chromatography on silica gel. Radioactivity was incorporated chiefly into the triglyceride, sterol, and polar lipid fractions, while lesser amounts of (14)C were found in the hydrocarbon, wax, diglyceride, monoglyceride, and fatty acid fractions; labeling of steryl esters was minimal. On thin-layer chromatography, the radioactive polar lipids had mobilities similar to lysolecithin, phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidic acid. The radioactive fatty acids of the different lipid fractions were separated by gas-liquid chromatography. The major (14)C-labeled acids were 16:0 and 18:0. Radioactivity was also detected in acids 14:0, 15:0, 16:1, 18:1, 18:2, 20:0, 20:1, 22:0, 24:0, 24:1, and 26:0. No radioactivity could be detected in arachidonic acid, although this fatty acid comprises 9% of the chromatographed fatty acids. The pattern of incorporated (14)C was different from the percentage mass composition of the fatty acids. Skin is therefore active in the biosynthesis of a wider variety of lipids than previously demonstrated.