Bombykol biosynthesis from deuterium-labeled (Z)-11-hexadecenoic acid

Summary (Z)-[11,12d ₂]-11-Hexadecenoic acid was applied topically to the pheromone gland of silkworm pupa. After eclosion, the gland components were analyzed by capillary GC-MS. (Z)-11-Hexadecenoic acid, a characteristic fatty acid of the gland, was found to be a precursor of bombykol, (Z)-11-hexadecenol and bombyk acid.We are greatful to Dr Y. Tamaki and Mr H. Sugie of the National Institute of Agricultural Science for mass spectrometric analysis and Dr M. Noda of Kyoto Prefectural University for valuable discussion. This work was supported by a Grant-in-aid for Scientific Research (to K.H. No. 56112011) from the Ministry of Education, Science and Culture of Japan.     

Chemical analysis of the pheromone blends produced by males and females of the neotropical moth,Mocis megas (Guénée) (Lepidoptera,Noctuidae, Catocalinae)

Summary Pheromonal secretions produced by females and males of the noctuid moth,Mocis megas (Guénée) have been analyzed by gas chromatography and mass spectrometry (EI (electron impact) and CI (chemical ionization)). The female sex pheromone was a blend of (Z,Z,Z) 3,6,9 heneicosatriene (55%) and (Z,Z) 3,6-cis-9S, 10R-epoxyheneicosadiene (45%). Male secretion produced at the level of a prothoracic organ was a blend of two unsaturated major hydrocarbons: (Z,Z) 6,9 heneicosadiene, (64%) and (Z,Z,Z) 3,6,9 heneicosatriene (24%) and C₁₉, C₂₀ and C₂₂ homologues (total ratio 12%), as minor components. The trienic hydrocarbon was present in both sexes. The behavioral role of this male secretion has not yet been elucidated.     

Identification and biological significance of 4-methyl-3Z,5-hexadienoic acid produced by males of the gall-forming tephritidsUrophora cardui (L.) andUrophora stylata (Fab.) (Diptera: Tephritidae)

Summary A new natural substance has been identified in the rectal ampullae of gall-forming fruit flies. The substance was found to be the only volatile compound in the rectal ampulla of maleUrophora cardui andUrophora stylata. GC-MS methods were used to characterize its structure as 4-methyl-3Z,5-hexadienoic acid. Physiological parameters such as the amount of the acid at different ages and under different conditions were investigated. The biological significance of the new volatile as an arresting pheromone was tested in several bioassays. The arrestant function could not be established, but the results gave hints of a territorial function between conspecific males. The results are discussed with respect to gland morphology and predictions of communication models among fruit flies.     

Eicosapentaenoic acid in tissue lipids ofPieris brassicae

Summary Larvae of the cabbage white butterfly,Pieris brassicae, have a dietary requirement for linolenic acid (C183n3) and were found to accumulate two other members of the n-3 family, C203n3 and C205n3 (eicosapentaenoic acid) especially in testicular phospholipids. Arachidonic acid was observed in trace amounts only. During diapause the relative titer of eicosapentaenoic acid increased in testicular phospholipids to about 4.2% of the fatty acids. Eicosapentaenoic acid is a possible precursor of prostaglandins, suggesting that prostaglandins of the 3-series predominate in this insect.     

Confirmation of sex pheromone biosynthesis from (16-D3)palmitic acid in the turnip moth using capillary gas chromatography

Summary (16-D₃)palmitic acid was applied topically to pheromone glands of the turnip moth. After incubation omega labeled analogues of fatty acid methyl esters and acetates were identified by gas chromatography with flame ionization detection and selected ion monitoring. The pheromone components (Z)-5-decenyl, (Z)-7-dodecenyl- and (Z)-9-tetradecenyl acetate were all biosynthesized from palmitic acid along a common pathway.     

tRNase Z: the end is not in sight

Although the enzyme tRNase Z has only recently been isolated, a plethora of data has already been acquired concerning the enzyme. tRNase Z is the endonuclease that catalyzes the removal of the tRNA 3′ trailer, yielding the mature tRNA 3′ end ready for CCA addition and aminoacylation. Another substrate cleaved by tRNase Z is the small chromogenic phosphodiester bis(p-nitrophenyl)phosphate (bpNPP), which is the smallest tRNase Z substrate known so far. Hitherto the biological function as tRNA 3′-end processing enzyme has been shown only in one prokaryotic and one eukaryotic organism, respectively. This review summarizes the present information concerning the two tRNase Z substrates pre-tRNA and bpNPP, as well as the metal requirements of tRNase Z enzymes. Received 29 March 2007; received after revision 15 May 2007; accepted 21 May 2007     

Regulatory steps in sex pheromone biosynthesis inMamestra brassicae L. (Lepidoptera: Noctuidae)

Summary The de novo biosynthesis of (Z)-11-hexadecenyl acetate, the most abundant pheromone component inM. brassicae, starting from acetate via palmitic acid, requires the presence of a pheromone-biosynthesis-activating neurohormone. Moreover, the conversion of palmitic acid to (Z)-11-hexadecenyl acetate is strongly dependent on the presence of the neurohormone. However, no significant dependence was found for the conversion of (Z)-11-hexadecenoic acid to (Z)-11-hexadecenyl acetate. This indicates that the neurohormonal control of pheromone biosynthesis inM. brassicae occurs at the level of palmitic acid.     

(Z)-1,17-diaminooctadec-9-ene,a novel aliphatic diamine from coccinellidae

Summary The isolation and structure determination of (Z)-1,17-diaminooctadec-9-ene from several species of Coccinellidae is reported.Maître de Recherches du Fonds National de la Recherche Scientifique.We gratefully acknowledge the Fonds National de la Recherche Scientifique for financial support. We express our sincere thanks to Professor K. S. Hagen for a generous gift ofH. leis conformis.     

Marine eicosanoids: Occurrence of 8-(R)-HETE in the starfishPatiria miniata

Summary The first isolation of 8-(R)-hydroxy-5Z, 9E, 11Z, 14Z-eicosatetraenoic acid [8-(R)-HETE] from a marine source, the pacific starfishPatiria miniata, is reported. 8-(R)-HETE occurs together with 8-(R)-hydroxy-5Z, 9E, 11Z, 14Z, 17Z-eicosapentaenoic acid.     

Host-plant oligosaccharins in the honeydew ofSchizaphis graminum (Rondani) (Insecta,Aphididae)

Summary The honeydew of the aphidSchizaphis graminum (Rondani) contains hetero-oligosaccharides (mol. wt>2200 D) having neutral sugar and uronic acid compositions similar to the pectic substances of the host plant,Sorghum biocolor (L.) Moench. These oligosaccharides are pectic fragments which result from the depolymerization of pectic substances in the phloem by aphid salivary polysaccharases.     

Chronic quercetin exposure affects fatty acid catabolism in rat lung

Dietary quercetin intake is suggested to be health promoting, but this assumption is mainly based on mechanistic studies performed in vitro. Previously, we identified rat lung as a quercetin target tissue. To assess relevant in vivo health effects of quercetin, we analyzed mechanisms of effect in rat lungs of a chronic (41 weeks) 1% quercetin diet using whole genome microarrays. We show here that fatty acid catabolism pathways, like beta-oxidation and ketogenesis, are up-regulated by the long-term quercetin intervention. Up-regulation of genes (Hmgcs2, Ech1, Acox1, Pcca, Lpl and Acaa2) was verified and confirmed by quantitative real time PCR. In addition, free fatty acid levels were decreased in rats fed the quercetin diet, confirming that quercetin affects fatty acid catabolism. This in vivo study demonstrates for the first time that fatty acid catabolism is a relevant process that is affected in rats by chronic dietary quercetin. Received 6 July 2006; received after revision 29 August 2006; accepted 28 September 2006     

The effect of endotoxin on membrane fatty acid composition in BCG-sensitized mice

Summary The effects of endotoxin on mouse liver phospholipid fatty acid composition have been investigated. Administration of endotoxin fromSalmonella abortus equi led to a decrease in the polyunsaturated fatty acid content of livers from mice sensitized with Bacille Calmette Guérin (GCG). The content of arachidonic acid fell significantly in both the phosphatidylcholine and phosphatidylinositol fractions whereas in the phosphatidylethanolamine fraction the linoleic acid content was significantly reduced. The polyunsaturated fatty acids were replaced by increased amounts of oleic acid and palmitic acid, leading to a reduction in the polyunsaturated to saturated fatty acid ratio.     

Insect tissues,not microorganisms,produce linoleic acid in the house cricket and the American cockroach

Summary Biosynthesis of linoleic acid, 182(n–6), was unambiguously demonstrated to occur in the cockroach,Periplaneta americana, and the cricket,Acheta domesticus. Axenic tissue from both of these insect species was demonstrated by radio-gas-liquid chromatography (radio-GLC) and radio-high-performance liquid chromatography (radio-HPLC) to incorporate [1-¹⁴C]acetate and [1-¹⁴C]oleate into this essential fatty acid.This work was supported by the National Science Foundation under grant DCB-8914417. We would like to thank Coby Schal for his generous gift of American cockroaches and Tania Kellermeyer for her excellent technical assistance.     

(Z)-9-tetradecen-1-ol and (Z)-9-tetradecenyl acetate: A potent attractant system for maleSesamia cretica Led. (Lep., Noctuidae)

Summary Field studies have shown that a combination of (Z)-9-tetradecenol with (Z)-9-tetradecenyl acetate is an effective attractant for maleSesamia cretica Led., a pest of sorghum crops. These studies also indicated that the most effective composition is 7525 (alcohol:acetate).We thank Dr E. Berio for the insect determination.     

(R)-(Z,E)-9,11-octadecadien-13-olide: An intriguing lactone fromHeliconius pachinus (Lepidoptera)

Summary A fourteen-membered lactone,(R)-(Z,E)-9,11-octadecadien-13-olide, was isolated from extruded abdominal glands of a Neotropical, nymphalid butterfly,Heliconius pachinus (Lepidoptera). This compound was obtained from mature adults of both sexes, but was not detected in young adults or pupae.     

Giffordene, 2Z, 4Z, 6E, 8Z-undecatetraene,is the odoriferous principle of the marine brown algaGiffordia mitchellae

Summary Giffordene, 2Z, 4Z, 6E, 8Z-undecatetraene, and five stereoisomers are new odoriferous C₁₁H₁₆-hydrocarbons from the marine brown algaGiffordia mitchellae. Their isolation and identification is described.Acknowledgments. We thank Prof. G. Ohloff for kindly providing us with synthetic 1,3,5,7-undecatetraenes and Prof. P. Schreier for GC/FTIR-analyses.     

Occurrence and biosynthesis of 11 (R)-hydroxy-eicosatetraenoic acid (11-R-HETE) in the Caribbean soft coralPlexaurella dichotoma

Gorgonian soft corals from the Caribbean Sea are known to contain prostaglandin-like compounds as well as other products of arachidonic acid lipoxygenation, and the formation of the latter has been suggested to represent the first step in prostaglandin biosynthesis. Here we present evidence for the presence of 11-R-hydroxy-5Z, 8Z, 12E, 14Z-eicosatetraenoic acid (11-R-HETE), as well as of the enzyme responsible for its biosynthesis, in the Caribbean gorgonianPlexaurella dichotoma. Lipid extracts fromP. dichotoma were purified by conventional SiO₂ column chromatography followed by reversed phase high-pressure liquid chromatography (HPLC). These yielded a component having chromatographic and spectroscopic properties identical to synthetic 11-HETE. Electron impact mass spectrometric analysis of the acetoxy-, methyl ester derivative of the compound confirmed its identity as 11-HETE, while chiral phase HPLC of the methyl ester derivative showed that the stereochemistry of the alcoholic carbon atom wasR. Enzymatically active homogenates fromP. dichotoma were able to convert both unlabelled and [³H] arachidonic acid into 11-HETE. In vitro biosynthesis of the latter metabolite was also observed with homogenates of the Mediterranean gorgonianParamuricea clavata, another non-prostaglandin-containing soft coral, thus suggesting that 11-R-HETE production is not necessarily accompanied by prostaglandin formation in gorgonian corals.     

Fatty acid profiles of major food sources of howler monkeys (Alouatta palliata) in the neotropics

Wild howler monkeys (Alouatta palliata) get most of their calories from carbohydrates (65%) and fats (18%) of native tropical plants, but little is known about their intake of individual fatty acids. The fatty acid composition of several natural food sources of howler monkeys collected in Panama was determined by gas-liquid chromatography. The predominant fatty acids were palmitic (30%), linoleic (23%), linoleic (23%), -linolenic (16%) and oleic (15%). Fatty acids with less than 16, and more than 18, carbon chains were uncommon (0–7%). Although total saturated fatty acids were high in some specific food sources (22–54% of total fatty acids and 8 energy %), most of the calories from fat in the animals' diets are derived from mono-and polyunsaturated fatty acids (9.75 energy %) All food sources had significant amounts of the -3 fatty acid, -linolenic acid (2.9 energy %). In terms of human diets, the howler monkey's fat consumption would not be considered atherogenic. Unless these animals show a particular adverse susceptibility to dietary fat, it is unlikely that their fat intake is the primary cause of the low, but significant, incidence of atherosclerosis that develops in these animals in the wild state.     

Long-chain fatty acid uptake by skeletal myocytes: a confocal laser scanning microscopy study

Studies of regulation of free fatty acid (FFA) utilization by skeletal muscles have focused on plasma FFA delivery and on intracellular factors affecting FFA metabolism. The present study was conducted to directly analyse the uptake process of fatty acids into single myocytes. Cells were isolated from the rat flexor digitorum brevis muscle. Confocal laser scanning microscopy was utilized to analyse the uptake of the fluorescent fatty acid derivative 12-NBD-stearate, which is not metabolized by muscle tissue. Uptake represented a saturable function of the unbound fatty acid concentration in the medium (K _m 366 ± 118 nM, V _max 2.1 ± 0.3 AU/s) and depended on the medium sodium concentration. Reduced buffer pH increased initial uptake rates, whereas lactate (10 mM) had no effect. Membrane hyper- and depolarization decreased uptake rates. This study demonstrates for the first time kinetic data from isolated myocytes with evidence for a carrier-mediated transport mechanism for long-chain fatty acids. Received 31 March 1998; accepted 8 May 1998     

Phytanic acid impairs mitochondrial respiration through protonophoric action

Refsum disease is a rare, inherited neurodegenerative disorder characterized by accumulation of the dietary branched-chain fatty acid phytanic acid in plasma and tissues caused by a defect in the alphaoxidation pathway. The accumulation of phytanic acid is believed to be the main pathophysiological cause of the disease. However, the exact mechanism(s) by which phytanic acid exerts its toxicity have not been resolved. In this study, the effect of phytanic acid on mitochondrial respiration was investigated. The results show that in digitonin-permeabilized fibroblasts, phytanic acid decreases ATP synthesis, whereas substrate oxidation per se is not affected. Importantly, studies in intact fibroblasts revealed that phytanic acid decreases both the mitochondrial membrane potential and NAD(P)H autofluorescence. Taken together, the results described here show that unesterified phytanic acid exerts its toxic effect mainly through its protonophoric action, at least in human skin fibroblasts. Received 4 August 2007; received after revision 26 September 2007; accepted 10 October 2007 J. C. Komen, F. Distelmaier: These authors contributed equally to this work.