Effect of exposure to chlorpyrifos on the cuticular and internal lipid composition of Blattella germanica males

The results of our research on the cuticular and internal lipids of Blattella germanica males provide new information on variation in the composition of the cuticular and internal lipids of B. germanica males after exposure to the presence of the insecticide. gas chromatography and gas chromatography‐mass spectrometry analyses were used to identify and quantify the cuticular and internal lipid composition in males and males exposed to insecticide. There were significantly more acids having an even number of carbon atoms in the molecule, and these were also generally in higher concentrations. The following acids were in a higher concentration: C16:0 and C18:1, C18:2, C18:0. In both males and males exposed to insecticide, 24 fatty acids ranging from C6 to C22 were determined. However, there was a significantly higher content of fatty acids in the surface lipids of B. germanica males after exposure to insecticide. Our results indicate a higher content of n‐alkanes, sterols, particularly cholesterol, fatty acids, and fatty acid methyl esters in the B. germanica surface after exposure to chlorpyrifos than in males that were not exposed.     

Effect of Conidiobolus coronatus on the Cuticular and Internal Lipid Composition of Tettigonia viridissima Males

Conidiobolus coronatus is an entomopathogenic fungus which has a potential as a biological control agent of insects. The cuticular and internal lipid composition of infected and noninfected Tettigonia viridissima males were analyzed by GC/MS. A total of 49 compounds were identified in the infected and noninfected males, including fatty acids, fatty acid methyl esters (FAMEs), n‐alkanes, alcohols, sterols, and other organic compounds. The most abundant components of the cuticular and internal lipids of the insects were fatty acids. After exposure to C. coronatus, the cuticular lipids of the T. viridissima males contained 17 free fatty acids from C(8) to C(22), while the cuticular lipids of the noninfected insects contained only 15 fatty acids from C(12) to C(24). The cuticular and internal lipids of both the infected and the noninfected males also contained five FAMEs from C(15) to C(19), seven n‐alkanes from C(25) to C(34), five alcohols from C(16) to C(25), five sterols, and the following six other organic compounds: azelaic acid, phenylacetic acid, glutaric acid, benzoic acid, sebacic acid, and glycerol. The compounds which were present only in the cuticular lipids of the infected males could be due to fungal infection.     

Comparison of the organic compounds composition of Hylobius abietis males and females before and after exposure to Beauveria bassiana infection

In the present study, the lipid composition from male and female Hylobius abietis is analyzed pre- and post-infection with Beauveria bassiana. The compounds are analyzed by gas chromatography-mass spectrometry. In the lipids of males and females fatty acids, fatty acid methyl esters, alcohols, amino acids and other organic compounds are identified. The lipids of males and females after B. bassiana exposure contain 31 and 33 organic compounds, respectively, whereas the lipids of non-infected males and females contain 30 and 37 compounds, respectively. The most abundant compounds in infected and non-infected males are fatty acids: C16:0, C18:0, C18:1 and C18:2. Contents of dominant compounds from the lipids of infected and non-infected males are similar to those extracted from the lipids of infected and non-infected females. It should be noted that the total mass of organic compounds is higher in non-infected insects than infected insects.     

Application of Two‐Way Hierarchical Cluster Analysis for the Identification of Similarities between the Individual Lipid Fractions of Lucilia sericata

The composition of the cuticular and internal lipids of larvae and pupae of Lucilia sericata was studied using chromatographic techniques. The lipids from both stages of L. sericata had similar free fatty acid (FFA) profiles and also contained alcohols and cholesterol. The range of the number of C‐atoms detected for these classes of compounds was to some extent similar in larvae and pupae, but the relative amounts of each class differed between stages. Saturated as well as unsaturated FFAs with even and odd numbered C‐atom chains were present in both cuticular and internal lipids. The alcohol fractions of L. sericata were represented by free, straight‐chain primary alcohols containing an even number of C‐atoms. The lipid composition of male and female L. sericata adults and the hydrocarbon composition of all stages of L. sericata had previously been analyzed. To have a full overview of the lipid composition and to identify similarities or dissimilarities between the individual lipid fractions in this insect species, two‐way hierarchical cluster analysis (HCA) was performed using also the data from these previous publications. The content of FFA 18 : 1 (n‐9) was noticed to be very high in the cuticular fractions of larvae and pupae as well as in all internal fractions (male, female, larvae, and pupae) and low in the cuticular fractions of male and female imago. The contents of FFAs 16 : 0 and 16 : 1 (n‐9), cholesterol, and the n‐alkanes n‐C₃₁, n‐C₂₉, n‐C₂₇, n‐C₂₅, and n‐C₂₃ varied between particular fractions, whereas the amounts of other compounds were similar in all fractions.     

Chemodiversity of Nonacosan‐10‐ol and n‐Alkanes in the Needle Wax of Pinus heldreichii

This is the first report of individual variability and population diversity of the contents of nonacosan‐10‐ol and n‐alkanes in the needle cuticular waxes of Bosnian pines originated from Montenegro, regarded as Pinus heldreichii var. leucodermis, and from Serbia, regarded as P. heldreichii var. pan?i?i. The amount of nonacosan‐10‐ol varied individually from 27.4 to 73.2% (55.5% in average), but differences between the four investigated populations were not statistically confirmed. The size of the n‐alkanes ranged from C₁₈ to C₃₃. The most abundant n‐alkanes were C₂₃, C₂₇, and C₂₅ (12.2, 11.2, and 10.8% in average, resp.). The carbon preference index (CPI) of the n‐alkanes ranged from 0.8 to 3.1 (1.6 in average), while the average chain length (ACL) ranged from 20.9 to 26.5 (24.4 in average). Long‐chain and mid‐chain n‐alkanes prevailed (49.6 and 37.9% in average, resp.). It was also found that the populations of P. heldreichii var. leucodermis had predominantly a narrower range of n‐alkanes (C₁₈? C₃₁) than the trees of the variety pan?i?i (C₁₈? C₃₃). Differences between the varieties were also significant for most of the other characteristics of the n‐alkane pattern (e.g., most abundant n‐alkanes, CPI, ACL, and relative proportion of short‐, mid‐, and long‐chain n‐alkanes). The principle component and cluster analyses of eleven n‐alkanes confirmed the significant diversity of these two varieties.     

Developmental Changes in the Sterol Composition and the Glycerol Content of Cuticular and Internal Lipids of Three Species of Flies

The glycerol concentration and the composition of cuticular and internal sterols in three medically and forensically important fly species, viz., Musca domestica, Sarcophaga carnaria, and Calliphora vicina, were analyzed. The cuticular and internal lipid extracts were separated by HPLC‐LLSD, after which the sterol fraction was characterized by GC/MS in total ion current (TIC) mode. The cuticular lipids of M. domestica larvae contained seven sterols, while in pupae and females, six sterols were identified. Five sterols were found in the cuticular lipids of M. domestica males. The internal lipids of M. domestica larvae and pupae contained six and seven sterols, respectively, while those of male and female flies contained only five sterols. Sitosterol, cholesterol, and campesterol were the dominant sterols in M. domestica, while campestanol, stigmasterol, sitostanol, and fucosterol were identified in low concentrations or in traces. In contrast, cuticular and internal lipids of S. carnaria and C. vicina contained only cholesterol. Glycerol was identified in all stages of M. domestica, S. carnaria, and C. vicina. For all the three examined fly species, the present study clearly showed species‐specific developmental changes in the composition of cuticular and internal sterols as well as in the glycerol concentration.     

The antifungal activity of fatty acids of all stages of Sarcophaga carnaria L. (Diptera: Sarcophagidae)

Fatty acids as components of cuticular lipids of insects play a significant role in antifungal in protection against fungal infection. The chemical composition of cuticular and internal extracts obtained from all developmental stages of flesh flies Sarcophaga carnaria was identified. The fatty acids were detected using gas chromatography coupled with mass spectrometry and the most abundant for all examined stages were: 18:1 > 16:0 > 16:1 > 18:0 > 18:2. Polyunsaturated fatty acids (PUFA) C20 were found in both, cuticular and internal extracts. GC–MS analysis showed higher relative content of PUFA in adults than in preimaginal stages.Fatty acids alone as well as their cuticular and internal extracts obtained from larvae, pupae male and female of S. carnaria were tested according to their potential antimicrobial activity against entomopathogenic fungi: Paecilomyces lilacinus, Paecilomyces fumosoroseus, Lecanicillium lecanii, Metarhizium anisopliae, Beauveria bassiana (Tve-N39) and B. bassiana (Dv-1/07). FA presented diverse antimicrobial activity depending on the length of the chain and the presence of unsaturated bonds. Short chain and unsaturated FA (6:0, 11:0, 13:0) have shown significantly stronger activity against fungi but they were detected in lower concentrations. PUFA inhibit fungal growth more effectively than unsaturated long chain fatty acids. Cuticular and internal extracts of all living forms of S. carnaria exhibited approximately equal activity against tested entomopathogenic fungi. We presumed that the most abundant saturated long chain FA and additionally PUFA founded in our analysis are involved in protecting the flies against fungal infection.     

Cuticle hydrolysis in four medically important fly species by enzymes of the entomopathogenic fungus Conidiobolus coronatus

Entomopathogenic fungi infect insects via penetration through the cuticle, which varies remarkably in chemical composition across species and life stages. Fungal infection involves the production of enzymes that hydrolyse cuticular proteins, chitin and lipids. Host specificity is associated with fungus–cuticle interactions related to substrate utilization and resistance to host‐specific inhibitors. The soil fungus Conidiobolus coronatus (Constantin) (Entomophthorales: Ancylistaceae) shows virulence against susceptible species. The larvae and pupae of Calliphora vicina (Robineau‐Desvoidy) (Diptera: Calliphoridae), Calliphora vomitoria (Linnaeus), Lucilia sericata (Meigen) (Diptera: Calliphoridae) and Musca domestica (Linnaeus) (Diptera: Muscidae) are resistant, but adults exposed to C. coronatus quickly perish. Fungus was cultivated for 3 weeks in a minimal medium. Cell‐free filtrate, for which activity of elastase, N‐acetylglucosaminidase, chitobiosidase and lipase was determined, was used for in vitro hydrolysis of the cuticle from larvae, puparia and adults. Amounts of amino acids, N‐glucosamine and fatty acids released were measured after 8 h of incubation. The effectiveness of fungal enzymes was correlated with concentrations of compounds detected in the cuticles of tested insects. Positive correlations suggest compounds used by the fungus as nutrients, whereas negative correlations may indicate compounds responsible for insect resistance. Adult deaths result from the ingestion of conidia or fungal excretions.     

Variations of Leaf Cuticular Waxes Among C3 and C4 Gramineae Herbs

Modern C4 plants are commonly distributed in hot and dry environments whereas C3 plants predominate in cool and shade areas. At the outmost of plant surface, the deposition and chemical composition of cuticular waxes vary under different environmental conditions. However, whether such variation of cuticular wax is related to the distribution of C3 and C4 under different environmental conditions is still not clear. In this study, leaves of six C3 Gramineae herbs distributed in spring, Roegneria kamoji, Polypogon fugax, Poa annua, Avena fatua, Alopecurus aequalis, and Oplismenus undulatifolius, and four C4 and one C3 Gramineae herbs distributed in summer, Digitaria sanguinalis, Eleusine indica, Setaria viridis, S. plicata, and O. undulatifolius, were sampled and analyzed for cuticular wax. Plates were the main epicuticular wax morphology in both C3 and C4 plants except S. plicata. The plates melted in C4 plants but not in C3 plants. The total cuticular wax amounts in C4 plants were significantly lower than those in C3 plants, except for O. undulatifolius. Primary alcohols were the most abundant compounds in C3 plants, whereas n‐alkanes were relatively the most abundant compounds in C4 plants. C₂₉ was the most abundant n‐alkane in C3 plants except for O. undulatifolius, whereas the most abundant n‐alkane was C₃₁ or C₃₃ in C4 plants. The average chain length (ACL) of n‐alkanes was higher in C4 than in C3 plants, whereas the ACL of n‐alkanoic acids was higher in C3 than C4 plants. The cluster analysis based on the distribution of n‐alkanes clearly distinguished C3 and C4 plants into two groups, except for O. undulatifolius which was grouped with C4 plants. These results suggest that the variations of cuticular waxes among C3 and C4 Gramineae herbs are related to the distribution of C3 and C4 plants under different environmental conditions.     

Role of cuticular lipids and water-soluble compounds in tick susceptibility to Metarhizium infection

The arthropod cuticle acts as a physiochemical barrier protecting the organism from pathogens' entry. Entomopathogenic fungi actively penetrate the cuticles of arthropod hosts and are therefore directly affected by cuticle composition. Previously we have observed that Metarhizium spp. developing on resistant ticks ultimately die without penetrating tick's cuticle, suggesting that the cuticles of resistant ticks have antifungal compounds. In the present study, lipids and water-soluble cuticular components were extracted from engorged female tick cuticles, of one susceptible and one resistant tick species to Metarhizium spp. While conidia exposed to lipids from the susceptible tick, Rhipicephalus annulatus, germinated and differentiated into appressorium, conidia exposed to lipids from the resistant tick, Hyalomma excavatum, were inhibited. Soluble cuticular component extracts from both susceptible and resistant ticks stimulated conidial germination but not appressorium differentiation. A comparative analysis of the fatty acid profile in lipid extract of each tick exhibited similar compositions, but the relative abundance of C16:0, C18:0, C18:1ω9C and C20:0 was 2–5 times higher in the extracts from resistant ticks. All of these fatty acids inhibited conidial germination in vitro at 1% and 0.1% w/v concentration, but C20:0 stimulated appressorium differentiation at low concentration. This is the first report demonstrating a possible link between the presence of antifungal compounds in a specific concentration in tick cuticle and tick resistance to infection.     

Sex- and age-related changes in the biophysical properties of cuticular lipids of the housefly,Musca domestica

We examined the biophysical properties of cuticular lipids isolated from the housefly, Musca domestica. Melting temperatures (T_m) of surface lipids isolated from female houseflies decreased from 39.3 °C to 35.3 °C as the females attained sexual maturity and produced sex pheromone, whereas those prepared from males did not change with age. Lipids melted over a 10–25 °C temperature range, and their physical properties were a complex function of the properties of the component lipids. The T_m of total cuticular lipids was slightly below that of cuticular hydrocarbons (HC), the predominant lipid fraction. Hydrocarbons were further fractionated into saturated, unsaturated, and methyl-branched components. The order of decreasing T_m was total alkanes > total HCs > methyl-branched alkanes > alkenes. For 1-day-old flies, measured T_ms of hydrocarbons were 1.3–5.5 °C lower than T_ms calculated from a weighted average of T_ms for saturated and unsaturated components. For 4-day-old flies, calculated T_ms underestimated T_m by 11–14 °C. © 1995 Wiley-Liss, Inc.     

Age‐Related Changes in Fatty Acids in Obese Offspring of Streptozotocin‐Induced Diabetic Rats

Objective: The long‐term effects of fetal hyperinsulinemia, time course of changes in liver and very‐low‐density lipoprotein (VLDL) lipid levels and fatty acid compositions were investigated in obese offspring of streptozotocin‐induced mildly diabetic rats. Research Methods and Procedures: Mild hyperglycemia in pregnant rats was induced by intraperitoneal injection of streptozotocin on day 5 of gestation. Control pregnant rats were injected with citrate buffer. Liver and VLDL lipids and fatty acids were analyzed in offspring at different ages. Results: At birth, obese pups had higher VLDL triglyceride levels, saturated fatty acids, and C20:4n‐6. They also had lower C18:2n‐6 proportions in VLDL triglycerides, phospholipids, and cholesteryl esters than controls pups. In 1‐month‐old male and female obese rats, VLDL and liver lipid amounts were similar to those in their respective controls; however, high levels of C18:2n‐6 and C20:4n‐6 were noted in liver and VLDL lipids. At the age of 2 months, liver and VLDL triglyceride levels were higher in obese females than in control females. Fatty acid abnormalities seen in obese rats included low C18:3n‐3 and high C22:6n‐3 proportions in liver triglycerides and phospholipids. At the age of 3 months, obese rats, both males and females, compared with control animals, had higher VLDL and hepatic lipids with reduced C20:4n‐6 levels and polyunsaturated/saturated fatty acids ratios in hepatic and VLDL triglycerides and phospholipids. Discussion: Fetal obesity, associated with alterations in VLDL lipid fatty acid composition, represents an important risk factor for adult obesity and diabetes.     

Discovery of novel trimethylalkanes in the internal hydrocarbons of developing pupae of Heliothis virescens and Helicoverpa zea

Novel trimethyl-branched alkanes which eluted with the monomethylalkanes were identified in the internal lipids of Helicoverpa zea but were not present in Heliothis virescens. Their structures were unique in that the first methyl branch occurred on carbon 2 and the 2nd and 3rd methyl branch points were separated by a single methylene. Novel trimethylalkanes identified from their chemical ionization and electron impact mass spectra were 2,18,20-trimethyltetratriacontane, 2,18,20-trimethylhexatriacontane, and 2,24,26-trimethyldotetracontane. Previous reports did not find these trimethylalkanes in the cuticular surface lipids of larvae, pupae or adults of either species. The internal pupal hydrocarbons of H. virescens and H. zea amounted to 123 μg and 304 μg per pupa, respectively. They consisted of n-alkanes (8 and 4%, respectively) and methyl-branched alkanes (88 and 94%, respectively). The n-alkanes ranged in chain length from approximately 21 to 35 carbons and the methyl-branched alkanes from approximately 26 to 55 carbons vs. methyl-branched alkanes from 28 to 37 carbons previously reported for hydrocarbons from the pupal cuticular surface. The major n-alkane was heptacosane (3.3 and 1.2%, respectively, in H. virescens and H. zea). The major methyl-branched alkanes in H. virescens were methylhentriacontane (15%), methyltritriacontane (12%) and dimethyltritriacontane (10%), and in H. zea were methylnonacosane (17%), dimethylnonacosane (9%) and methylhentriacontane (20%). Except for the novel trimethylalkanes, the methylalkane branch points were predominantly on odd-numbered carbons as has been reported for these and other species.     

Volatile compounds from the symbiotic system Azolla filiculoides‐Anabaena azollae bacteria

Abstract

Azolla filiculoides is an aquatic pteridophyte that may be used as animal food, biofertilizer and phytoremediation. Its volatile composition was never studied although several phytochemical analyses were performed. The volatile composition of A. filiculoides grown outdoors in a pond at the Botanical Garden of Lisbon University (BGLU) or in culture conditions as well as the effect of different harvesting times and the storage type were evaluated. The volatiles isolated by hydrodistillation and distillation‐extraction were analysed by gas chromatography and gas chromatography‐mass spectrometry. The oil of all the A. filiculoides samples studied affords a yellowish colour and an unpleasant odour in a yield of 0.01% (v/fw). Alcohols, aldehydes, alkanes and ketones dominated the culture samples, while aldehydes, alcohols, terpenoids and alkanes represented the main volatiles of the BGLU samples. Some quantitative differences were detected in seasonal and type of storage (fresh, dry or frozen at ?20°C) studies of A. filiculoides from the BGLU. The BGLU and culture volatiles showed qualitative differences: 2‐ethyl‐1‐hexanol was only identified in the fern culture, whereas acetophenone, pentylfuran, acetylpyridine and 2‐octanone were only detected in BGLU samples. The dendrogram showed two distinct clusters (culture and BGLU samples). The possible biological origin and bioactivity of some of the volatile compounds is discussed.

Abbreviations: FID, flame ionization detector; i.d., internal diameter; v/fw, volume by fresh weight; GC, gas chromatography; GC‐MS, gas chromatography‐mass spectrometry; u, unified atomic mass unit     

Isolation and identification of cuticular compounds from the mediterranean flour moth,Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), their antibacterial activities and biological functions

Cuticular analysis of Ephestia kuehniella females by gas chromatography-mass spectrometry revealed the presence of four groups of chemical compounds including alkane, alcohol, aldehyde and fatty acid. The cuticular n-alkanes ranged from 12 to 18, 20, 23, 24 and 29 carbon atoms in the chain. The most abundant n-alkanes detected in the cuticular extracts were C₁₄ (14.98%) and C₁₈ (8.15%). Cuticular fatty acids included hexadecenoic acid, 9-octadecenoic acid and 9,12-octadecenoic acid. Two types of alcohol including, 2-methyl-Z,Z-3,13-octadecadienol and 9-methyl-Z-10-tetradecen-1-ol acetate, were found in the cuticular lipids of the females. Two aldehyde components, (E)-11-hexadecenal and 9,17-octadecadienal, were identified in the cuticular extract of E. kuehniella. Antibacterial activity of the cuticular compounds was tested against Bacillus subtilis, Bacillus thuringiensis and Escherichia coli. These compounds from the moths inhibited the growth of Gram-positive bacteria. The functional characteristics of the cuticular compounds operating as pheromones, species-associated compounds and host-resistant compounds to bacterial infection are discussed.     

Successful high‐level accumulation of fish oil omega‐3 long‐chain polyunsaturated fatty acids in a transgenic oilseed crop

Omega‐3 (also called n‐3) long‐chain polyunsaturated fatty acids (≥C20; LC‐PUFAs) are of considerable interest, based on clear evidence of dietary health benefits and the concurrent decline of global sources (fish oils). Generating alternative transgenic plant sources of omega‐3 LC‐PUFAs, i.e. eicosapentaenoic acid (20:5 n‐3, EPA) and docosahexaenoic acid (22:6 n‐3, DHA) has previously proved problematic. Here we describe a set of heterologous genes capable of efficiently directing synthesis of these fatty acids in the seed oil of the crop Camelina sativa, while simultaneously avoiding accumulation of undesirable intermediate fatty acids. We describe two iterations: RRes_EPA in which seeds contain EPA levels of up to 31% (mean 24%), and RRes_DHA, in which seeds accumulate up to 12% EPA and 14% DHA (mean 11% EPA and 8% DHA). These omega‐3 LC‐PUFA levels are equivalent to those in fish oils, and represent a sustainable, terrestrial source of these fatty acids. We also describe the distribution of these non‐native fatty acids within C. sativa seed lipids, and consider these data in the context of our current understanding of acyl exchange during seed oil synthesis.     

Identification and field and laboratory tests of the sex pheromone of Cerconota anonella Sepp. (Lepidoptera: Oecophoridae)

The Annona fruit borer, Cerconota anonella Sepp., is a serious agricultural pest in many tropical areas of the world. The identification of an attractant for male C. anonella could offer new methods for pest detection and control. A mixture of compounds extracted from female C. anonella elicited antennal depolarization in the male borer. These compounds were identified as octadecanal, 1‐octadecanol, octadecyl acetate, (Z)‐octadec‐9‐enal (Z9‐18:Ald), (Z)‐octadec‐9‐en‐1‐ol (Z9‐18:OH) and [(Z)‐octadec‐9‐enyl] acetate (Z9‐18:Ac) by one‐ and two‐dimensional gas chromatography–mass spectrometry. In laboratory bioassays, synthetic individual compounds as well as synthetic mixtures were found to be attractive to males. In addition, field tests using Delta traps with 1 mg of the ternary mixture composed of Z9‐18:Ac, Z9‐18:Ald and Z9‐18:OH in the ratio of 1 : 3 : 5 caught as many males as traps containing virgin females. The ternary mixture of Z9‐18:Ac, Z9‐18:Ald and Z9‐18:OH was identified as attractant to C. anonella males and can be used to detect and control populations of this insect in Annonaceae plantations.     

Chemotaxonomic Implications of the n‐Alkane Composition and the Nonacosan‐10‐ol Content in Picea omorika,Pinus heldreichii,and Pinus peuce

The n‐alkane composition and the nonacosan‐10‐ol content in the needle cuticular waxes of Serbian spruce (Picea omorika), Bosnian pine (Pinus heldreichii), and Macedonian pine (Pinus peuce) were compared. The amount of nonacosan‐10‐ol in the needle waxes of P. omorika was higher than those in P. heldreichii and P. peuce. The range of n‐alkanes was also wider in P. omorika (C₁₈–C₃₅) than in P. heldreichii and P. peuce (C₁₈–C₃₃). The dominant n‐alkanes were C₂₉ in the needle waxes of P. omorika, C₂₃, C₂₇, and C₂₅ in those of P. heldreichii, and C₂₉, C₂₅, C₂₇, and C₂₃ in those of P. peuce. The waxes of P. omorika contained higher amounts of n‐alkanes C₂₉, C₃₁, and C₃₃, while those of P. heldreichii and P. peuce had higher contents of n‐alkanes C₂₁, C₂₂, C₂₃, C₂₄, and C₂₆. The principal component analysis of the contents of nine n‐alkanes showed a clear separation of the Serbian spruce populations from those of the two investigated pine species, which partially overlapped. The separation of the species was due to high contents of the n‐alkanes C₂₉ and C₃₁ (P. omorika), C₁₉, C₂₀, C₂₁, C₂₂, C₂₃, and C₂₄ (P. heldreichii), and C₂₈ (P. peuce). Cluster analysis also showed a clear separation between the P. omorika populations on one side and the P. heldreichii and P. peuce populations on the other side. The n‐alkane and terpene compositions are discussed in the light of their usefulness in chemotaxonomy as well as with regard to the biogeography and phylogeny of these rare and endemic conifers.     

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.