The effect of the entomopathogenic fungus Conidiobolus coronatus on the composition of cuticular and internal lipids of Blatta orientalis females

The composition of cuticular and internal lipids in females of the cockroach Blatta orientalis L. exposed to the entomopathogenic fungus Conidiobolus coronatus is investigated. The compositions of the fatty acids, n‐alkanes, alcohol, sterols and methyl esters in the lipids are chemically characterized. Although contact with virulent colonies of the fungus does not induce insect mortality, significant changes in the lipid profiles, both cuticular and internal, are found. The cuticular extracts of a control group of B. orientalis females contain 24 compounds varying in carbon chain length from C6 to C22. The main cuticular fatty acids identified are: C16:1, C16:0, C18:1 and C18:0_. The cuticular lipids of B. orientalis females after exposure to C. coronatus contain only 14 free fatty acids from C8 to C20. The highest concentrations identified are C16:0, C18:2 and C18:1. Analysis by gas chromatography‐mass spectrometry identifies the presence of a homologous series of n‐alkanes containing from 25 to 31 carbon atoms. In the case of the insects after fungal exposure, the content of the n‐alkanes in the cuticular lipid is two‐fold higher compared with the controls. Of the cuticular lipids, 11 alcohols are found, ranging from C12:0 to C20:0. There is no presence of alcohols in the internal lipids of the control B. orientalis females and in all of the extracts from the B. orientalis females after fungal exposure. In the samples analyzed, the most common sterol is cholesterol. This is present in the cuticular lipids and the internal lipids of all of the insects sampled. The cuticular and internal lipids of females contain five fatty acid methyl esters, ranging in size from C15 to C19.     

Effects of Three Bacterial Infections on Serum Lipids of Rabbits

Alteration of the rabbit serum lipids as a result of three bacterial infections was studied by quantitative thin-layer and gas-liquid chromatography. Anthrax infection slightly changed the serum lipid. Cholesterol did not change, though free fatty acids, triglycerides, and cholesteryl esters doubled, and lecithin increased threefold. Tularemia infection produced drastic changes in the serum lipid content of rabbits, increasing levels of cholesterol over 4-fold, free fatty acids 17-fold, triglycerides 11-fold, cholesteryl esters 2.5-fold, and lecithin almost 3-fold. Pneumococcus infection increased cholesterol 2.5 times, free fatty acids were more than doubled, triglycerides were increased 9.5 times, and lecithin was increased almost 4 times. Gas-liquid chromatographic analysis of the methyl esters of free fatty acids showed only quantitative changes in these acids due to infection. Some possible mechanisms of alteration of serum lipid content are discussed.     

Agonistic behaviour of female Tegenaria atrica in the presence of different aged spiderlings

The agonistic behaviour of adult female T. atrica increases with increasing age of spiderlings until 80 days post-emergence, then decreases. In all cases, cannibalism of spiderlings increases markedly after completion of their pre-dispersal period with a correlation between the switch of behaviour, from tolerance to cannibalism, and a modification of individual’s cuticular compounds. Experiments that compare spiderlings weight and mobility indicate that female agonistic behaviour are always low with spiderlings in pre-dispersal period, and high with spiderlings in post-dispersal period. Female reproductive state and the weight/mobility of spiderlings are not the only factors controlling the adult female’s agonistic behaviour towards spiderlings on her web, as tactochemical information plays an important role in modulating agonistic behaviour after close contact between female spiders and spiderlings. The agonistic behaviour of females appears to correspond with a change in the increase of polar compound levels (methylesters and fatty acids) and the decrease of apolar compound levels (hydrocarbons) in spiderlings of different ages.     

Liquid chromatographic analysis of sebum lipids and other lipids of medical interest

A technique is described for the high-pressure liquid chromatographic (HPLC) analysis of sebum lipid classes. The lipid classes present in sebum are separated by gradient elution HPLC from a microparticulate silica column and detected using a moving-wire detector. The system described can be linked to a computer. Quantitation can be carried out by comparing peak areas obtained with those of an internal standard. Peak trapping for further investigations of the separated components, for example by gas chromatography—mass spectrometry, is very easy.Sebum lipids are separated into the following lipid classes: hydrocarbons and squalene, cholesterol esters and wax esters, fatty acids as their methyl esters, triglycerides, 1,3-diglycerides, 1,2-diglycerides, free cholesterol, monoglycerides and other polar materials. Besides to sebum, the method has been successfully applied to other lipid mixtures, such as serum lipids. Examples of other applications are shown.     

Variation in plasma lipids during the reproductive cycle of male and female desert tortoises,Gopherus agassizii

Plasma triacylglycerol, phospholipid, cholesterol, cholesterol esters, fatty acids, and total lipids were measured in 30 female and 20 male desert tortoises (Gopherus agassizii) during the annual reproductive cycle in the eastern Mojave desert, Nevada. Blood samples were collected at monthly intervals from April to October. All lipid fractions, with the exception of free fatty acids, were significantly higher in female plasma than in male plasma in all months of the year. In contrast, free fatty acids were higher in male plasma than in female plasma in all months. The seasonal pattern in estradiol secretion mirrored that of triacylglycerol, phospholipid, cholesterol, and total lipid, all of which showed a significant correlation with the hormone. Estradiol and the vitellogenesis-associated lipids were all significantly higher in August, September, October, and April than in June. The seasonal variation in cholesterol ester levels in females did not correlate with any of the reproductive events and did not appear to be involved in yolk precursor formation. Total lipid in males showed a negative correlation with testosterone and spermatogenesis. Individual fatty acids in the June and August samples (at the highest and lowest estradiol levels) were compared in male and female plasma. The percent of C18:3n3, C18:2n6, C18:1n9, C20:5n3, and C22:5 were significantly higher in the June female plasma sample than in the August sample. Docosahexanoic (C22:6n3) acid was barely detectable in female plasma in either month.     

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.     

Lipid and sterol composition of the pollen of the west african oilpalm, Elaeis guineensis

The lipid classes, fatty acid methyl esters and the sterols of oilpalm pollen were analysed. The neutral lipid fraction consisted of triglycerides, esterified and free sterols and trace amounts of hydrocarbons. Monogalactosyl and digalactosyl diglycerides, phosphatidyl choline, phosphatidyl inositol and phosphatidyl ethanolamine represented the polar lipids. The major fatty acids were linoleic, palmitic and linolenic acids together with small to trace amounts of oleic, stearic, arachidic, myristic, lauric, palmitoleic and margaric acids. Unsaturated fatty acids predominated over saturated ones in the ratio of 3:2. The 4-desmethyl sterols were the major phytosterols in the free form but they constituted a lower proportion of the sterols in the esterified state. 28-Isofucosterol was isolated and characterized as the principal sterol.     

Neutral Lipids and Phospholipids of Free-Living and Bacteroid Forms of Two Strains of Rhizobium Infective on Lotus pedunculatus

The neutral lipids and phospholipids of two strains of rhizobia in their free-living state and in symbiosis with a host plant are described. The principal lipid classes found were the polymer poly-beta-hydroxybutyrate, phospholipids, free fatty acids, glycerides, methyl esters, aliphatic alcohols, and hydrocarbons. The lipids include unusual unsaturated methyl-branched and saturated methoxy-branched fatty acids. Most components were found to be common to both forms of both strains, although the proportions varied. A number of strain differences could be discerned.     

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.     

Olfactory cues and nest recognition in the solitary bee Osmia lignaria

Abstract.  The use of olfactory cues for nest recognition by the solitary bee Osmia lignaria is studied in a greenhouse environment. Glass tubes are provided as nesting cavities to allow the in-nest behaviour of bees to be observed. In addition, each glass tube is cut into three sections for experimental manipulation and for subsequent chemical analysis. Nesting females drag their abdomen along the tube before exiting, spiral inside the tube, and sometimes deposit fluid droplets from the tip of the abdomen. For the manipulation, the outer section, the middle section, or both sections are removed and replaced with similar clean glass tube sections, and the behaviour exhibited by test females is recorded upon arrival in front of the nesting site and inside the nesting tubes. The resulting hesitation behaviour displayed by females after treatments appears to indicate the loss of some olfactory cues used for nest recognition inside the entire nest. Chemical analysis of the depositions inside the nesting tube, as well as analysis of the cuticular lipids of the nesting bees, reveals the presence of free fatty acids, hydrocarbons and wax esters.     

CHANGES IN CEREBRAL CORTICAL LIPIDS IN COBALT-INDUCED EPILEPSY

Abstract– In control rats and in rats rendered epileptic by insertion of cobalt slivers into the cerebral cortex, total free fatty acids, free cholesterol, esterified cholesterol, triglycerides and phospholipids were measured in normal and lesion areas of cerebral cortex. The cortical lipid profile of the adult rat resembled that of the whole brain of very young rats rather than that of adult whole brain, with the principal differences from whole adult brain being lower total lipid content, increased proportions of phosphatidyl choline in the phospholipid fraction, and higher levels of cholesterol esters. Cobalt-induced epilepsy was associated with significant changes in cerebral cortical lipids in the area of the lesion and in the non-necrotic tissue adjacent to the lesion. The total lipid in the area of the lesion decreased sharply as a result of reductions in free cholesterol and total phospholipids. The levels of cholesterol esters and triglycerides increased in the area of the lesion, and cholesterol esters were also increased in the adjacent tissue. In addition there were decreases in the proportion of phosphatidyl ethanolamine in the phospholipids from the lesion site and adjacent tissue and decreases in the proportions of oleic, arachidonic and nervonic acids (unsaturated acids), and an increase in the proportions of lignoceric acid in the phospholipids. In the site of the lesion only, we observed a decrease in phospholipid palmitic acid and an appreciable increase in the proportions of an unidentified long-chained fatty acid.     

Concentration and fatty acid composition of cholesteryl esters of normal human brain

Abstract— —Cholesteryl esters were isolated from the cerebral cortex and white matter of human brains at different ages, and their concentration and composition determined. The esters were separated from other lipids by chromatography on silicic acid and finally purified by TLC. The fatty acids were converted to the methyl esters by alkaline trans-methylation and analysed by GLC. A TLC method was elaborated for quantitative determination of small amounts of cholesteryl esters in the presence of free cholesterol. The concentration of cholesteryl esters was only 0·1–0·2 per cent of the total cholesterol content of cerebral tissue in older children and adults. During early myelination the concentration was many times greater, especially in the white matter but it never exceeded 2 per cent of the total cholesterol in any subject. The major fatty acids of human brain cholesteryl esters were oleic, palmitic, palmitoleic and arachidonic acid. After completion of myelination, arachidonic acid constituted the major fatty acid. There were fairly small differences in the fatty acid pattern of the cholesteryl esters between grey and white matter, but the concentration of polyunsaturated fatty acids was larger in the grey matter. Cholesteryl esters appear to play an important role in the metabolism of the phosphoglyceride fatty acids in cerebral tissue.     

Hemolymph lipids and flight activity in Helicoverpa zea (Boddie) (lepidoptera: Noctuidae)

In this study the flight activity of female and male Helicoverpa zea (Boddie) moths was observed and compared to hemolymph lipid concentrations. The major male and female H. zea flight activity occurred between simulated dusk (1700) and dawn (0300). Male flight activity was up to 7 times greater than females through 6 days after eclosion except for the 1st day (0.8 times). Females had a unimodal pattern of flight activity, peaking between dusk and 2 h later. Males had a bimodal pattern; one between dusk and 2 h later, and another 3 h after dusk, continuing for h. Prior to dusk, total neutral hemolymph lipids (neutral) of H. zea day 4 moths was 64 μg/μl for males and 48 μg/μl for females. Typical lipid composition in day 4 males prior to flight was 1,2-diacylglycerides (DG) (50% w/w), triacylglycerides (TG) (35%), cholesterol esters (2%), and less than 1% monoacylglycerides and cholesterol. The remainder consisted of free fatty acids (<0.5 μg/μl), and various uncharacterized phospholipids and lipophilic compounds. Hemolymph DG concentration patterns were similar between day 4 males and females, were highest in both sexes prior to, during, and after flight (approximately 32 μg/μl), and then decreased steadily throughout the flight period to approximately 16 μg/ml as flight ceased. Hemolymph TG were lower than DG, but followed the same pattern except at 2100 and 2300. In day 4 males between 2100 and 2300, TG increased to 33 μg/μl which was when DG was lowest (15 μg/μl) and their flight activity was highest. Hemolymph DG decreased (26 to 20 μg/μl) in day 4 females between 2100 and 2300 as TG remained fairly constant (18 μg/μl).     

Lipid compounds of the umbilical cord vein and their alterations in preeclampsia

The lipid composition of vascular walls changes during development, ageing and pathological processes. Preeclampsia is the most common pregnancy-associated pathological syndrome. It is accompanied by significant remodelling of the extracellular matrix, both in the umbilical cord vessels and in the surrounding Wharton's jelly. Lipids of the umbilical cord have not been extensively studied. Here we evaluate the lipid composition of the umbilical cord vein and its alteration in preeclampsia. Thin layer chromatography and high-performance liquid chromatography were employed for these analyses. It was found that the umbilical cord vein wall, as with most human tissues, contains free fatty acids, mono-, di- and triacylglycerols, free cholesterol and its esters. The characteristic feature is the presence of high amounts of monounsaturated fatty acids, mainly myristoleic acid (C14:1) and oleic acid (C18:1), and polyunsaturated fatty acids, including eicosapentaenoic acid (C20:5) and docosahexaenoic acid (C22:6), which are rather minor lipid components of most human tissues. They exist both in a free form and in a form of acylglycerols and cholesterol esters. Preeclampsia is associated with an increase in the accumulation of free fatty acids, acylglycerols and cholesterol esters in the umbilical cord vein wall, with a proportional reduction in unsaturated fatty acid contents in all the investigated lipid fractions. Total amount of myristoleate was similar to control values. It is suggested that stimulation of lipolysis in maternal tissues increases supply of free fatty acids to foetal blood and promotes the accumulation fatty acids and their esters in some foetal vascular walls.     

The function of the post-pharyngeal glands of the red imported fire ant, Solenopsis invicta buren

Using radiolabelled triglycerides and fatty acids we have shown that these 2 lipids are absorbed into the haemolymph of the imported fire ant, Solenopsis invicta Buren from the post-pharyngeal gland. The post-pharyngeal glands attain their greatest weight and contain the highest hexane extractable lipid in establishing queens which have just reared the first minum brood. The lipid content of the digestive system is greatest in queens initiating a mating flight with the majority of the lipid contained in the crop. During colony establishment by the queen the lipid content of the crop moves forward, some is fed to the developing larvae and some moves into the post-pharyngeal gland. The hexane extractable lipid from the postpharyngeal gland of newly mated queens consists of hydrocarbons, sterols. tri-, di-, and monoglycerides and free fatty acids with a trace of wax esters.Excision of the post-pharyngeal glands from mated established queens causes no noticeable change in their behaviour or the behaviour they elicit from the remainder of the colony. However, post-pharyngeal glandectomized females lost weight and died in ca. 2 months although their crop and midgut contained food. The post-pharyngeal glands therefore appear to function in much the same way as a gastric caecum.     

Composition of plasma fatty acids and non-cholesterol sterols in anorexia nervosa

Anorexia nervosa is a model of simple starvation accompanied by secondary hyperlipoproteinemia. The pattern of plasma fatty acids influences the levels of plasma lipids and lipoproteins. The concentration of plasma lathosterol is a surrogate marker of cholesterol synthesis de novo, concentrations of campesterol and beta-sitosterol reflect resorption of exogenous cholesterol. The aim of the study was to evaluate fatty acids in plasma lipid classes and their relationship to plasma lipids, lipoproteins, cholesterol precursors and plant sterols. We examined 16 women with anorexia nervosa and 25 healthy ones. Patients with anorexia nervosa revealed increased concentrations of total cholesterol, triglycerides, HDL-cholesterol, campesterol and beta-sitosterol. Moreover, a decreased content of n-6 polyunsaturated fatty acids was found in all lipid classes. These changes were compensated by an increased content of monounsaturated fatty acids in cholesteryl esters, saturated fatty acids in triglycerides and both monounsaturated and saturated fatty acids in phosphatidylcholine. The most consistent finding in the fatty acid pattern concerned a decreased content of linoleic acid and a raised content of palmitoleic acid in all lipid classes. The changes of plasma lipids and lipoproteins in anorexia nervosa are the result of complex mechanisms including decreased catabolism of triglyceride-rich lipoproteins, normal rate of cholesterol synthesis and increased resorption of exogenous cholesterol.     

Stearic acid methyl ester: A new extracellular metabolite of the obligate methylotrophic bacterium Methylophilus quaylei

Methyl esters of fatty acids, free fatty acids, and hydrocarbons were found in the culture liquid and in the cellular lipids of the obligate methylotrophic bacterium Methylophilus quaylei under optimal growth conditions and osmotic stress. The main extracellular hydrophobic metabolite was methyl stearate. Exogenous free fatty acids C₁₆–C₁₈ and their methyl esters stimulated the M. quaylei growth and survivability, as well as production of exopolysaccharide under osmotic and oxidative stress, playing the role of growth factors and adaptogens. The order of hydrophobic supplements according to the ability to stimulate bacterial growth is C_{18: 1} > C_{18: 0} > C_{16: 0} > methyl oleate > methyl stearate > no supplements > C_{14: 0} > C_{12: 0}. The mechanism underlying the protective action of fatty acids and their methyl esters is discussed.     

Patterns of biosynthesis and accumulation of hydrocarbons and contact sex pheromone in the female german cockroach,Blattella germanica

De novo synthesis of contact female sex pheromone and hydrocarbons in Blattella germanica was examined using short in vivo incubations. Accumulation of pheromone on the epicuticular surface and the internal pheromone titer were related to age-specific changes in hydrocarbon synthesis and accumulation in normal and allatectomized females. The incorporation of radiolabel from [1-¹⁴C]propionate into the cuticular methyl ketone pheromone fraction was positively related to corpora allata activity during two gonotrophic cycles. During peak pheromone production the total internal lipid fraction contained greater titers of pheromone than the cuticular surface, and it too exhibited a cycle internally, preceding the rise in external pheromone. This suggests that synthesis and accumulation of pheromone internally are followed by transport of pheromone to the epicuticular surface where it accumulates. Radiolabel was incorporated efficiently into both cuticular and internal hydrocarbons after the imaginal molt and until the peak of pheromone synthesis, but it declined to lower levels before ovulation and throughout pregnancy. The internal hydrocarbon titer decreased 58% after oviposition, suggesting deposition in the egg case. It remained relatively unchanged during pregnancy and increased again during the second gonotrophic cycle. In allatectomized females, hydrocarbon synthesis was reduced relative to control females until oviposition in the latter. However, subsequent rates of hydrocarbon synthesis in allatectomized females (without oothecae) exceeded the rates in sham-operated females (with oothecae). In the absence of ovarian uptake of hydrocarbons, the internal titer increased without the decline found in control females at oviposition. As internal hydrocarbons increased, so did cuticular hydrocarbons and both internal and cuticular methyl ketone pheromones. These patterns corresponded well with feeding patterns in sham-operated and allatectomized females, suggesting that pheromone production is normally regulated by stage-specific feeding-induced hydrocarbon synthesis (precursor accumulation internally) and juvenile hormoneinduced conversion of hydrocarbon to pheromone. They also suggest that both the cuticle and the ovaries might be target sites for hydrocarbon and possibly methyl ketone deposition. © 1994 Wiley-Liss, Inc.     

Cuticular lipids of adults and puparia of the Australian sheep blowfly Lucilia cuprina (Wied.)

The presence of a strong contact component in the sex and ovipositing behavior of the sheep blowfly Lucilia cuprina Wied. prompted an investigation into the chemical composition of the cuticular wax of the adult male and female flies as well as that of the blowfly puparia. Thin-layer chromatography indicated that the lipids in all the waxes examined comprise hydrocarbons, nonglyceryl esters, triglycerides, free fatty acids, and hydroxy compounds, probably diglycerides and monoglycerides. Phospholipids were not detected. Straight-and branched-chain saturated compounds, the latter often pre-dominating, are present in the hydrocarbon, free fatty acid, and ester fractions. Unsaturated molecules were absent. The hydrocarbons resemble those of the cricket to some extent, but the absence of unsaturated compounds is in striking contrast to both the cricket and the cockroach. Pheromones may be present in the low molecular weight fatty acids obtained on brief extraction of the insects.     

Neutral lipids of leaves and stems of Trifolium repens

The neutral lipids of white clover leaves and stems have been separated into wax esters, free fatty acids, free fatty alcohols, free sterols, triglycerides and hydrocarbons. The wax esters were mainly of C₁₈ di- and tri-unsaturated fatty acids and C₃₀ fatty alcohol. Linolenic acid was the predominant free fatty acid and triacontanol was the principal free fatty alcohol. Of the hydrocarbons, C₂₉ and C₃₁ were present in the largest amounts.