Inter-specific avoidance of egg-associated semiochemicals in four tortricids

Oviposition of four tortricid pests of vineyards (the European grapevine moth and the grape berry moth) and fruit orchards (the codling moth and the oriental fruit moth) is deterred by a blend of straight chain fatty acids and esters of fatty acids that have been identified in the eggs of one of them: the European grapevine moth (EGVM)Lobesia botrana. This is the first evidence of inter-specific recognition of an egg-like signal in moths. We demonstrate that oviposition site selection is influenced by population density, avoidance of deterrent being most important when females are isolated. Inter-specific egg recognition might be an important phenomenon, especially in species competing for a common food resource. We propose the term oviposition regulating synomone for molecules and blends that affect the inter-specific spacing of eggs.     

Furan fatty acid steryl esters from the marine spongeDictyonella incisa which show inflammatory activity

Summary Three new furan fatty acids, (9Z, 19Z)-3, 6-epoxyhexacosa-3,5,19-tetraenoic acid (1a), (8Z, 11Z, 14Z, 17Z)-3, 6-epoxyeicosa-3,5,8,11,14,17-hexaenoic acid (2a), and (8Z, 11Z, 14Z, 17E)-3, 6-epoxyeicosa-3,5,8,11,14,17-hexaenoic acid (3a), and a new polyunsaturated fatty acid (5Z, 8Z, 11Z, 14Z, 17E)-eicosa-5,8,11,14,17-pentaenoic acid (6a), present in the spongeDictyonella incisa as the respective steryl esters, have been isolated as methyl esters and their structures have been determined by spectral and chemical analysis. The furan fatty acid esters have shown a high inflammatory activity, which suggests their potential role as feeding deterrents.     

Lipid accumulation by a cellulolytic strain ofAspergillus niger

Lipid accumulation by a cellulolytic mold,Aspergillus niger, was studied. The amount of lipid accumulated ranged from 13.6–16.6% on various carbon sources, namely glucose, xylose, avicel (microcrystalline cellulose) and bagasse (a natural lignocellulosic substrate). Neutral lipids, phospholipids and glycolipids of the mycelia varied from 41.0–46.2%, 34.9–38.4% and 18.7–22.6% of total lipids, respectively. Unsaturated fatty acids comprised around 80% of total fatty materials with linoleic and oleic acid predominating. Of the four nitrogen sources tested, NH₄Cl was the best source for lipid synthesis from cellulose (bagasse). Optimum temperature range for growth and lipid synthesis was 25–30°C.     

Oviposition stimulants of aCitrus-feeding swallowtail butterfly,Papilio xuthus L

Summary A methanolic extract ofCitrus unshiu induces oviposition by females of aCitrus-feeding swallowtail butterfly,Papilio xuthus L. The chemical factors responsible for stimulating oviposition were isolated and characterized as 5-hydroxy-N-methyltryptamine, adenosine, vicenin-2, narirutin, hesperidin and rutin. An artificial blend of these six components elicited significant oviposition behavior, apparently identical to that induced by contact with intactCitrus leaves.     

The egg-lipid composition of the ‘living fossil’ reptile tuatara (Sphenodon punctatus)

Summary The lipid composition of two tuatara eggs was examined. The eggs contained triacylglycerol (80%) and phospholipid (12%) as their major lipid fractions. Fatty acid analyses of the individual lipid classes indicated the presence of essential fatty acids, linoleic and arachidonic acids. The quantity of such acids in the egg yolk lipids would suggest they are factors for survival as illustrated in other species.     

Thiyl radicals in biosystems: effects on lipid structures and metabolisms

Thiyl radicals are intermediates of enzyme- and radical-driven biochemical processes, and their potential as reactive species in the biological environment has been somehow underestimated. From organic chemistry, however, it is known that thiyl radicals isomerize the double bonds of unsaturated fatty acids to a mixture with very dominating trans isomers. Recently, this reaction has been particularly studied for biosystems, focusing on the effect of thiyl radicals on the natural all-cis double bonds of unsaturated phospholipids, which undergo a conversion to the unnatural trans form. In this paper we report briefly the role of thiyl radicals in biosystems, describe the main features of the radical-induced cis-trans isomerization process under both in vitro and in vivo conditions, and reflect on some consequences for membrane structures, lipid metabolism and enzymatic reactions.Received 29 October 2004; received after revision 3 December 2004; accepted 4 January 2005     

Physiological importance of ω-3/ω-6 polyunsaturated fatty acids in man. An overview of still unresolved and controversial questions

Summary The essentiality of (-6) and (-3) fatty acids in mammals is well known. Nevertheless, some important points remain unclear concerning their implication in physiology. After a short discussion about the definition of essential fatty acids deficiency, this brief overview deals with some of these points, pointing out some of the unresolved questions. Different subjects are approached concerning the (-6) and (-3) fatty acids metabolism: desaturases, eicosanoids, production, as well as some of their metabolic effects on cell membranes, intestinal function, glucose and lipid metabolism, haemorheology.     

Regulation of carbohydrate metabolism by the optic tentacles of the garden snailCryptozona ligulata (Gastropoda-Stylommatophora)

Summary The presence of a hyperglycemic factor in the optic tentacles of the snailC. ligulata is reported here. A preliminary characterization based on crude extracts indicates the factor to be water-soluble, heat labile and to be an albumin. The ablation of optic tentacles and injection of optic tentacle extract into operated and normal snails caused a rise in blood sugar, total carbohydrate and glycogen in the foot muscle and mantle and a decrease in hepatopancreatic glycogen. The ablation also caused a fall in blood free amino acids and a rise in the tissues, which was reversed in the blood and foot muscle by injection of the extract. Possible conversion of amino acids to total carbohydrates and glycogen by gluconeogenesis is suggested.     

Residual influences on fecundity in drosophilid species

Summary A residual influence of males and females on oviposition has been examined in 7 drosophilids. There was evidence for oviposition deterrence inDrosophila funebris, with males as well as females producing the inhibitory effect. In contrast, male residues stimulated oviposition inZaprionus tuberculatus. Male residues also stimulated oviposition and appeared to serve as an aggregation cue inD. melanogaster.     

Two related butterfly species avoid oviposition near each other's eggs

Summary Some butterfly species avoid egg-laying on plants which already bear conspecific eggs, and thus reduce food competition between their offspring. In twoPieris species the females produce in their accessory glands an oviposition-deterring pheromone (ODP), which is combined with the egg during oviposition. The ODP collected from eggs or accessory glands ofP. brassicae inhibits oviposition byP. rapae and vice versa. The ODP of either species stimulates tarsal receptors in both species. The antennae of the two pierids respond to the volatiles of their own and each other's eggs. Thus the ODPs of the two species may reduce not only intraspecific, but also interspecific food competition between their larvae.     

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.     

Alkaloidal oviposition stimulants for a danaid butterfly,Ideopsis similis L., from a host plant,Tylophora tanakae (Asclepiadaceae)

Chemicals releasing oviposition by an Asclepiadaceae feeder,Ideopsis similis, were identified from a host plant,Tylophora tanakae. A strong positive response was evoked by a methanolic extract of the plant, which proved to contain multiple stimulants. A mixture of two phenanthroindolizidine alkaloids, (+)-isotylocrebrine and (–)-7-demethyltylophorine, isolated from organic fractions, elicited significant ovipositional responses from females.     

Oviposition rhythm of individualDrosophila pseudoobscura

Summary D. pseudoobscura oviposits mostly during the day with some oviposition at night. Oviposition varies from tight clustering to loose scattering from different individuals. Daily oviposition ranges from good to poor to no eggs over 24 h. Althoug this species was an excellent model for the eclosion rhythm it does not serve as a good model for continued study of the oviposition rhythm under present experimental conditions.I thank C.S. Pittendrigh for supplying me with a wild type culture ofD. pseudoobscura.     

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.     

Fatty acid modulation of antiestrogen action and antiestrogen-binding protein in cultured lymphoid cells

Summary Nonsteroidal antiestrogens reversibly and specifically inhibited the proliferation of two estrogen receptornegative lymphoid cell lines (EL4 and Raji) in a dose-dependent manner. [³H]Thymidine incorporation of concanavalin A-stimulated primary splenocytes was also inhibited by 10^–6 M clomiphene (1-[4-(2-diethylaminoethoxy)phenyl]-1,2-diphenyl-2-chloroethylene). The antiproliferative effect could be prevented by the simultaneous presence in the growth medium of 10^–5 M linoleic acid or 10^–5 M arachidonic acid but not by 10^–6 M estradiol. Both lymphoid cell lines had high affinity antiestrogen-binding sites whose affinity could be altered by conditions of growth. Growth of EL4 cells in RPMI 1640 medium supplemented with charcoal-pretreated 5% fetal calf serum (charcoal-stripped medium) resulted in significantly higher affinity (K_d 0.54 nM±0.11 nM; n=6) than growth in medium supplemented with untreated serum (complete medium) (K_d=1.68 nM±0.48 nM; n=6) (p<0.001). This change in affinity was partly due to removal of fatty acids from the growth medium by charcoal pretreatment, since addition of 10^–5 M linoleic acid or 10^–5 M gamma-linolenic to charcoal-stripped medium decreased the affinity of the antiestrogen-binding protein. In contrast, growth in 10^–5 M stearic acid or 10^–5 M oleic acid did not significantly alter the affinity of the antiestrogen-binding protein, whereas 10^–5 M palmitic acid significantly increased its affinity. The same fatty acids were also tested for their intrinsic effects on EL4 cell proliferation. Oleic, linoleic and gamma-linolenic acids were growth stimulatory while stearic and palmitic acids were not. Thus linoleic and gamma-linolenic acids whose presence in the growth medium was associated with decreased affinity of [³H]tamoxifen (1-[4-(2-dimethylaminoethoxy)phenyl]-1,2-diphenylbut-1(Z)-ene) binding to the intracellular antiestrogen-binding protein were also growth stimulatory. Unsaturated fatty acids have previously been shown to inhibit binding of [³H]tamoxifen to the antiestrogen-binding protein in a cell-free system. The present observations demonstrate that unsaturated fatty acids also modify the affinity of the antiestrogen-binding protein in intact cells.     

The choice of oviposition sites by the lady bird beetleAdalia bipunctata (L.)

Summary Adalia bipunctata females lay eggs on brussels sprout leaves in presence or absence of aphids, but the latter furnish an additional stimulus. The glass walls of the jar attracted the adults to lay eggs on it to some extent. Presence of cemented eggs did not hinder the oviposition of the adults on the brussels sprouts leaves.     

Effect of taurine administration on liver lipids in guinea pig

Summary The oral administration of 0.4% taurine in drinking water for 14 consecutive days showed the following hepatic effects in male guinea pig. The percentage of tauro-conjugated biliary bile acids was increased from 17.2–54.2%; the ratio liver weight/body weight was increased, and fatty change was induced. Liver triglyceride concentration was accordingly increased; diglyceride and phosphatidylcholine concentrations were reduced by the treatment, while phosphatidylethanolamine level was not affected. These changes suggest an adverse effect of taurine administration on phosphatidylcholine hepatic synthesis.     

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     

ω10-Lipoxygenase products of α-linolenic acid are esterified to phospholipids inHydra vulgaris

We have recently reported the occurrence of 9(R)-hydroxy-, 9(R)-hydroperoxy- and 9-keto-octadeca-10E,12Z,15Z-trienoic acids (9-HOTrE, 9-HPOTrE and 9-KOTrE) inHydra vulgaris, and their biosynthesis from -linolenic acid (-LA) through the action of an enantioselective 10(R)-lipoxygenase (10-LO). Here we describe the finding of these -LA metabolites as esters to the 2-position of phosphatidylcholine, phosphatidylethanolamine and, in trace amounts, phosphatidylinositol. Small amounts of a compound co-eluting with an authentic standard of 9(R)-hydroxy-octadeca-10E,12Z-dienoic acid, a metabolite potentially derived from the action of 10-LO on linoleic acid, were also found esterified with phospholipids. Since direct peroxidation of membrane lipids has been described, experiments were aimed at establishing whether -LA metabolite-containing phospholipids could originate, inH. vulgaris, from either spontaneous or 10-LO-catalyzed oxidation of phospholipid-bound -LA. Incubation of either unlabelled or radiolabelled PUFA-containing phosphoglycerides withH. vulgaris 10-LO did not result in their peroxidation. This suggests that -LA and LA metabolites are incorporated into glycerophospholipids after their formation by 10-LO, and that, as in mamals, membrane phospholipids may serve as a reservoir for these bioactive compounds. This is the first example in an invertebrate species of lipoxygenase products esterified to phosphoglycerides.     

Influence of the feeding conditions on competition betweenDrosophila melanogaster andDrosophila simulans for their oviposition site

Summary Under low feeding conditions, the number of eggs laid by the femaleDrosophila melanogaster or the femaleDrosophila simulans is frequency dependent: it increases simultaneously with the increase of the frequency of the species to which the female belongs. This result could be explained by the role of scents in the choice of the oviposition site inDrosophila.