Long-chain free fatty acids from Momordica cochinchinensis leaves as attractants to its insect pest,Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae)

Extraction, thin layer chromatography, and gas chromatography–mass spectrometry of young, mature, and senescent leaves of Momordica cochinchinensis Spreng revealed 13 free fatty acids, representing a total of 82.29, 91.30, and 68.52% of fatty acids in young, mature, and senescent leaves, respectively. Palmitic acid was the predominant fatty acid followed by stearic acid in three types of leaves. The free fatty acids from young, mature, and senescent leaves attracted female Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae) at the minimal concentrations of 4, 2, and 8 μg, respectively; whereas the mixtures of synthetic fatty acids mimicking free fatty acids of young, mature, and senescent leaves showed attraction at the minimal concentrations of 4, 2, and 10 μg, respectively, in Y-shaped glass tube olfactometer bioassay under laboratory condition. The results indicate that A. foveicollis may employ long-chain free fatty acids as an olfactory cue for host location. The individual synthetic fatty acids mimicking the proportions detected in three types of leaves were also evaluated through olfactometer bioassay. Only synthetic palmitic acid at the minimal amount of 2.17 μg attracted the insect. A synthetic blend of fatty acids mimicking 8 μg free fatty acid concentration of mature leaves or an amount of 5.42 μg palmitic acid produced the highest attraction of the insect. Hence 5.42 μg palmitic acid might be used for insect pest management program such as baited traps.     

Free fatty acids from the weed,Polygonum orientale leaves for attraction of the potential biocontrol agent,Galerucella placida (Coleoptera: Chrysomelidae)

Extraction, thin layer chromatography and gas chromatography-mass spectrometry of leaf surface waxes of Polygonum orientale L. (Polygonaceae) weed revealed 11, 15 and 11 free fatty acids in young, mature and senescent stages. Oleic acid was the predominant in young leaves (5950 ± 111 µg); whereas palmitic acid was the predominant fatty acids, representing 4247.5 ± 23 and 6644 ± 110 µg in mature and senescent leaves, respectively. Both tridecanoic and heneicosanoic acids were not detected in young and senescent leaves, and myristic and heptadecanoic acids were not identified in young leaves; whereas lauric and nonadecanoic acids were not detected in senescent leaves. The free fatty acids from young, mature and senescent weed leaves, and the mixtures of synthetic fatty acids mimicking free fatty acids of three types of weed leaves attracted female Galerucella placida (Coleoptera: Chrysomelidae) at the minimal amounts of 2, 1 and 2 leaf equivalent free fatty acids, respectively, in Y-shaped glass tube olfactometer bioassays under laboratory conditions. Individual synthetic pentadecanoic, palmitoleic, stearic, nonadecanoic and docosanoic acids at 44.82, 9.91, 92.22, 18.33 and 15.88 µg, respectively, elicited attraction of the insect. A synthetic blend of 3.59, 7.89, 44.82, 9.91, 32.31, 18.33 and 15.88 µg of lauric, myristic, pentadecanoic, palmitoleic, heptadecanoic, nonadecanoic and docosanoic acids, respectively, indicated highest attraction of the insect.     

Long-chain alkanes: allelochemicals for host location by the insect pest, Epilachna dodecastigma (Coleoptera: Coccinellidae)

Extraction, thin-layer chromatography, and gas chromatography–mass spectrometry of leaf surface waxes of Momordica charantia L. (Cucurbitaceae) revealed that 20 n-alkanes between n-C₁₅ and n-C₃₆, except n-C₃₄ and n-C₃₅, commonly occur in young, mature, and senescent stages. Hentriacontane, hentriacontane, and hexatriacontane were the predominant compounds in young, mature, and senescent leaves, respectively. The cuticular alkanes from young, mature, and senescent leaves attracted the female insect, Epilachna dodecastigma (Wied.), at 25–400, 25–400, and 100–400 μg concentrations, respectively, whereas the mixtures of synthetic alkanes mimicking cuticular alkanes of young, mature, and senescent leaves showed attraction at 100–400, 100–400, and 200–400 μg concentrations, respectively, in Y-shaped glass tube olfactometer bioassay. The difference in insect attraction is probably due to the absence of branched-chain alkanes in the synthetic mixtures. Individual synthetic heptacosane, nonacosane, and hentriacontane at 28.19–56.90, 32.04–64.08, and 60.44–120.88 μg, respectively, elicited attraction of the insect. A synthetic blend of 4.82, 4.91, 5.71, 6.74, 56.39, 7.94, 62.42, 120.88, and 36.33 μg of nonadecane, eicosane, heneicosane, pentacosane, heptacosane, octacosane, nonacosane, hentriacontane, and tritriacontane, respectively, was most attractive to the insect.     

The attractiveness of odorous esterified fatty acids to the potential biocontrol agent,Altica cyanea

The fatty acid composition of foliar buds, young, mature, and senescent leaves, and stem parts of the rice-field weed, Ludwigia adscendens L. (Onagraceae) was analyzed by thin layer chromatography and gas chromatography flame ionization detection. The analysis of fatty acid composition revealed that saturated fatty acids (i.e., C14:0, C16:0, and C18:0) were prevailing compounds among the all weed parts except senescent leaves where C18:1 was predominant. The esterified fatty acids isolated from different weed parts over the range of 10–100 μg/ml followed by individual synthetic esterified fatty acids that were identified from the esterified extracts of different weed parts, and a mixture of synthetic esterified fatty acids except esterified eicosenoic acid and docosahexaenoic acid were applied to identify their role as a chemical cue for a potential biocontrol agent, Altica cyanea (Weber) (Coleoptera: Chrysomelidae) in a Y-tube olfactometer under laboratory conditions. In this bioassay, the esterified fatty acids from mature leaves and stem parts of this weed attracted A. cyanea at 20–100 μg/ml and at 80 μg/ml concentrations, respectively. Clear attraction was recorded by female A. cyanea insects in the mixture of synthetic esterified fatty acids at 60, 80, and 100 μg/ml concentrations. It is thus concluded that A. cyanea rely on an effective proportion of esterified fatty acids as an olfactory cue for attraction.     

Cadmium Alters the Concentration of Fatty Acids in THP-1 Macrophages

Fatty acid composition of human immune cells influences their function. The aim of this study was to evaluate the effects of known toxicant and immunomodulator, cadmium, at low concentrations on levels of selected fatty acids (FAs) in THP-1 macrophages. The differentiation of THP-1 monocytes into macrophages was achieved by administration of phorbol myristate acetate. Macrophages were incubated with various cadmium chloride (CdCl₂) solutions for 48 h at final concentrations of 5 nM, 20 nM, 200 nM, and 2 μM CdCl₂. Fatty acids were extracted from samples according to the Folch method. The fatty acid levels were determined using gas chromatography. The following fatty acids were analyzed: long-chain saturated fatty acids (SFAs) palmitic acid and stearic acid, very long-chain saturated fatty acid (VLSFA) arachidic acid, monounsaturated fatty acids (MUFAs) palmitoleic acid, oleic acid and vaccenic acid, and n-6 polyunsaturated fatty acids (PUFAs) linoleic acid and arachidonic acid. Treatment of macrophages with very low concentrations of cadmium (5–200 nM) resulted in significant reduction in the levels of arachidic, palmitoleic, oleic, vaccenic, and linoleic acids and significant increase in arachidonic acid levels (following exposure to 5 nM Cd), without significant reduction of palmitic and stearic acid levels. Treatment of macrophages with the highest tested cadmium concentration (2 μM) produced significant reduction in the levels of all examined FAs: SFAs, VLSFA, MUFAs, and PUFAs. In conclusion, cadmium at tested concentrations caused significant alterations in THP-1 macrophage fatty acid levels, disrupting their composition, which might dysregulate fatty acid/lipid metabolism thus affecting macrophage behavior and inflammatory state.     

Selective retention of n-3 and n-6 fatty acids in human milk lipids in the face of increasing proportions of medium chain-length (C10-14) fatty acids

This paper reports the results of our analysis of the impact high levels of de novo fatty acids have on the proportions of essential and non-essential fatty acids in human milk lipids. The data for seven fatty acids (linoleic, alpha-linolenic, arachidonic (AA), docosahexaenoic (DHA), palmitic, stearic and oleic) were derived from several studies conducted in Nigeria. The proportion by weight of each of these fatty acids was plotted versus the proportion of C10-14 fatty acids. As the proportion of C10-14 fatty acids increased from 15 to 65%, there was not a proportional decrease in the percentages of all seven fatty acids, but, instead, preferential incorporation of the essential fatty acids, AA and DHA into the triacylglycerol component of the milk. At the same time, the proportions of stearic and oleic acid declined by 69% and 86%, respectively. However, the proportions of linoleic acid, palmitic acid, DHA, AA and alpha-linolenic acid, in milk lipids decreased by only 44%, 40%, 39%, 28% and 2.3%, respectively. These observations indicate that as the contribution of C10-14 fatty acids increases, essential fatty acids are preferentially incorporated into milk triacylglycerols at the expense of oleic acid and stearic acid.     

Assessment of fatty acids in dog left ventricular myocardium

The concentration and composition of fatty acids in four lipid classes in biopsies of dog left ventricular myocardium were determined, using gas-liquid chromatography. When precautions were taken to minimize lipolysis during storage of the tissue and the homogenization process, the following results were obtained: 29 ± 10 nmol non-esterified fatty acids, 2.98 ± 2.41 μmol triacylglycerol, 149 ± 51 nmol cholesteryl esters and 23.76 ± 3.38 μmol phospholipid (expressed as fatty acid moiety per gram of wet tissue). The concentration of non-esterified fatty acids was 15 to 300 times lower than reported in literature.The main constituents of the non-esterified fatty acids were palmitic, stearic and oleic acid. Triacylglycerol consisted of approximately 40% esterified oleic acid. Linoleic acid accounted for 40% of the fatty acids in the cholesteryl-esters class. More than half of the fatty acid moiety of total phospholipids was linoleic acid and arachidonic acid.     

Lipid and Fatty Acid composition of chloroplast envelope membranes from species with differing net photosynthesis

Lipid and fatty acid compositions were determined for chloroplast envelope membranes isolated from spinach (Spinacia oleracea L.), sunflower (Helianthus annuus L.), and maize (Zea mays L.) leaves. The lipid composition was similar in sunflower, spinach, and undifferentiated maize chloroplast envelope membranes and different in maize mesophyll chloroplast envelope membranes. The predominant lipid constituents in all envelope membranes were monogalactosyldiglyceride (27 to 46%), digalactosyldiglyceride (18 to 33%), and phosphatidylcholine (7 to 30%). The fatty acid composition was also similar in sunflower and spinach chloroplast envelope membranes in comparison to those from maize. The major acyl fatty acids of the chloroplast envelope membrane were palmitic (C_16:0, 41 and 36%) and linolenic (C_18:3, 29 and 40%) acids for spinach and sunflower; palmitic (77%) and stearic (C_18:0, 12%) acids for young maize; and palmitic (61%), stearic (14%), and linolenic (13%) acids for mature maize. The differences in lipid and acyl fatty acid compositions among these plants which vary in their rates of net photosynthesis were largely quantitative rather than qualitative.     

Effect of Thiolactomycin on Fatty Acid Synthesis in Higher Plants

Thiolactomycin (TLM), an antibiotic from Nocardia sp. No. 2-200,inhibited fatty acid synthesis in Avena leaves, with the concentrationcausing 50% inhibition being 0.38µg/ml. This antibioticis more inhibitory to the elongation of palmitic to oleic acidthan to the de novo synthesis of palmitic acid in both spinachchloroplasts and Avena leaves, in contrast to the effect ofcerulenin which inhibits de novo synthesis but not fatty acidelongation. On the other hand, TLM is less inhibitory to furtherelongation of stearic acid to very long chain fatty acids inpea seeds. The inhibition rate decreased in the order of synthesisof arachidic, behenic and lignoceric acid. (Received December 26, 1986; Accepted April 24, 1987)     

Bionomics of <Emphasis Type="Italic">Momordica cochinchinensis</Emphasis> Fed <Emphasis Type="Italic">Aulacophora foveicollis</Emphasis> (Coleoptera: Chrysomelidae)

The effects of feeding on root by the larvae and three types of Momordica cochinchinensis Spreng (Cucubitaceae) leaves (young, mature and senescent) by the adults of Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae) were studied under laboratory conditions. Total larval developmental time was 19.7 ± 0.2 days by feeding on young roots. Adult males lived for 28.4 ± 1, 65.7 ± 1.1 and 22.8 ± 1.3 days on young, mature and senescent leaves, respectively; whilst adult females lived for 34.3 ± 1.2, 68.5 ± 0.9 and 26.4 ± 1.4 days on young, mature and senescent leaves, respectively. Fecundity was highest in mature leaves fed insects (202.2 ± 10.6). Total carbohydrate, protein, lipid, nitrogen and amino acid were much higher in root followed by mature leaves than young and senescent leaves. Moisture content was highest in mature leaves than the roots, young and senescent leaves. Phenols were greatest in young leaves followed by mature leaves and least in senescent leaves and roots of the said plant. Flavonols were higher in young leaves and least in root. These results suggest that A. foveicollis adults perform better on mature leaves than young and senescent leaves for their nutrition.     

Biology of <Emphasis Type="Italic">Galerucella placida</Emphasis> Baly (Coleoptera: Chrysomelidae) on the Rice-Field Weed <Emphasis Type="Italic">Polygonum orientale</Emphasis> L. (Polygonaceae)

Galerucella placida Baly (Coleoptera: Chrysomelidae) is a promising biocontrol agent of the rice-field weed Polygonum orientale L. (Polygonaceae) in India and Bangladesh. The longevity of G. placida adults was related with nutrients and antinutrients of young, mature and senescent leaves of P. orientale. Mature leaves of P. orientale had higher level of nutrients (carbohydrates, proteins, lipids, nitrogen and amino acids) and lower level of antinutrients (phenols and flavonols) compared to young and senescent leaves. Higher level of carbohydrates, proteins, lipids, nitrogen, amino acids including water content, and lower phenol and flavonol content of mature leaves had influenced higher survival of G. placida. Total larval developmental and pupal periods were 26.27 ± 0.45 SE and 7.06 ± 0.17 SE days on mature weed leaves, respectively; whilst adult males and females lived for 52.15 ± 0.33 SE and 58.0 ± 0.38 SE days on mature leaves, respectively. Fecundity of individual G. placida was 133.3 ± 3.2 SE eggs during life time. The net reproductive rate, generation time, intrinsic rate of increase, finite rate of increase and doubling time were 66.675, 27.5376, 0.1525, 1.2502 and 4.5452 days, respectively, under laboratory conditions (27 ± 0.5 °C, 12L:12D photoperiod, 65 ± 5% RH).     

Identification of steroid hormones and fatty acids during gonadal maturation of spiny lobster Panulirus homarus

Information on steroid hormones and fatty acids that play roles in lobster reproduction is still very limited although the data are indispensable to seed production in hatchery. The study was designed to identify steroid hormones and fatty acids during gonadal maturation of spiny lobster (Panulirus homarus). Male spiny lobsters were treated with and without thyroxine injection. Female spiny lobsters were treated with and without eyestalk ablations during mature and immature gonad developments. Androst-5-en-17-one,3β (androst) and estran-3-one,17β (estran), two steroid hormones were identified at different levels of gonadal maturity of spiny lobsters. High concentrations of androst and estran were detected in the male spiny lobsters treated with thyroxine injections. Estran showed high concentrations in female brood stock of spiny lobsters during oogenesis stages both without eyestalk ablation and with ablation of one or two eyestalks, except in the immature female gonads. It was found that stearic acid was the highest and dominant fatty acid in mature male spiny lobster. Stearic acid, oleic acid, palmitic acid and caprylic acid were fatty acids with high concentrations in immature and mature female spiny lobsters. After 30 days in captivity, only stearic acid and oleic acid were found dominantly in eyestalk ablated mature female spiny lobsters.     

Lipid productivity and fatty acid composition in Chlorella and Scenepdesmus strains grown in nitrogen-stressed conditions

Thirty Chlorella and 30 Scenedesmus strains grown in nitrogen-stressed conditions (70 mg L^?1 N) were analyzed for biomass accumulation, lipid productivity, protein, and fatty acid (FA) composition. Scenedesmus strains produced more biomass (4.02?±?0.73 g L^?1) after 14 days in culture compared to Chlorella strains (2.57?±?0.12 g L^?1). Protein content decreased and lipid content increased from days 8 to 14 with an increase in triacylglycerol (TAG) accumulation in most strains. By day 14, Scenedesmus strains generally had higher lipid productivity (53.5?±?3.7 mg lipid L^?1 day^?1) than Chlorella strains (35.1?±?2.8 mg lipid L^?1 day^?1) with the lipids consisting mainly of C16–18 TAGs. Scenedesmus strains generally had a more suitable FA profile with higher amounts of saturated fatty acids and monounsaturated fatty acids (MUFAs) and a smaller polyunsaturated fatty acid (PUFA) component. Chlorella strains had a larger PUFA component and smaller MUFA component. The general trend in the FA composition of Chlorella strains was oleic > palmitic > α-linolenic = linoleic > eicosenoic > heptadecenoic > stearic acid. For Scenedesmus strains, the general trend was oleic > palmitic > linoleic > α-linolenic > stearic > eicosenoic > palmitoleic > heptadecenoic acid. The most promising strains with the highest lipid productivity and most suitable FA profiles were Scenedesmus sp. MACC 401, Scenedesmus soli MACC 721, and Scenedesmus ecornis MACC 714. Although Chlorella sp. MACC 519 had lower lipid productivity, the FA profile was good with a lower PUFA component compared to the other Chlorella strains analyzed and a low linolenic acid concentration.     

Incorporation and metabolism of stearic, oleic, linoleic and alpha-linolenic acids in minimal deviation hepatoma 7288 C cells.

Minimal Deviation Hepatoma 7288 C cells were cultured in confluent layer with labeled stearic, oleic, linoleic and alpha-linolenic acids. The kinetics of incorporation and conversion to higher homologs was studied. The maximum amounts incorporated in nmoles per mg of cellular protein for stearic, oleic, linoleic and alpha-linolenic acids were 39, 115.6, 90 and 230 respectively. alpha-linolenic acid was converted to octadeca-6,9,12,15-tetraenoic acid (18:1), eicosa-11,14,17-trienoic acid (20:3), eicosa-8,11,14,17 and 5,11,14,17-tetraenoic acids (20:4) and eicosa-5,8,11,14,17-pentaenoic acid (20:5), and also to myristic, palmitic, palmitoleic, stearic and oleic acids. By a mathematical approach, the endogenous pool size of alpha-linolenic acid available for conversion to eicosa-5,8,11,14,17-pentaenoic acid, were calculated. Both values decreased when the cells were preincubated with unlabeled alpha-linolenic acid.     

Relationship of changes in the fatty acid compositions and fruit softening in peach (Prunus persica L. Batsch)

Fatty acid compositions of peach (Prunus persica L. Batsch) mesocarp tissues from ‘Kawanakajima Hakuto’ and its firm-fleshed mutant ‘Shuangjiuhong’ were examined by gas chromatography during the developmental stages from 20 days before to 20 days after fruit ripening. Fruits were harvested at 4-day intervals from July to September. The predominant fatty acids were linoleic, palmitic and linolenic acids with 27.66–48.93 %, 23.59–31.65 %, and 12.08–28.35 % in ‘Shuangjiuhong’, and 32.64–42.79 %, 23.53–28.95 %, 16.14–39.15 % in ‘Kawanakajima Hakuto’, respectively. Saturated fatty acids (palmitic and stearic acids) remained relatively constant throughout the ripeness period. On the contrast, from 15 days before ripening, notable decline in oleic acid and increase of linoleic and linolenic acids were observed in both cultivars. In addition, from 10 days before ripening, much lower levels of oleic and linolenic acids and higher proportion of linoleic acid were observed in ‘Shuangjiuhong’ than those found in ‘Kawanakajima Hakuto’. And notably higher SFA level, lower levels of UFA and IUFA in the firm-fleshed peach were investigated during those stages. Correlation analysis showed that oleic acid and SFA had very significantly positive, whereas linolenic acid, UFA and IUFA had significantly negative correlation with fruit firmness. These results above suggest that lower levels of oleic and linolenic acids, UFA and IUFA, and higher linoleic acid and SFA content represent fruits with firmer flesh and help to retain the fruit texture.     

Steroid 5alpha-reductase inhibitory activity and hair regrowth effects of an extract from Boehmeria nipononivea

The acetone extract of Boehmeria nipononivea showed both potent 5alpha-reductase inhibitory activity and hair regrowth promotion effects on mice. 5alpha-Reductase inhibitory activity-guided fractionation led to six active fatty acids: alpha-linolenic, linoleic, palmitic, elaidic, oleic and stearic acids. The extract of B. nipononivea, and alphalinolenic, elaidic and stearic acids exhibited a hair regrowth effect.     

Quantitative trait locus analysis of saturated fatty acids in a population of recombinant inbred lines of soybean

Soybean [Glycine max (L.) Merr.] is an important crop which contributes approximately 58% of the world??s oilseed production. Palmitic and stearic acids are the two main saturated fatty acids in soybean oil. Different levels of saturated fatty acids are desired depending on the uses of the soybean oil. Vegetable oil low in saturated fatty acids is preferred for human consumption, while for industrial applications, soybean oil with higher levels of saturated fatty acids is more suitable. The objectives of this study were to identify quantitative trait loci (QTL) for saturated fatty acids, analyze the genetic effects of single QTL and QTL combinations, and discuss the potential of marker-assisted selection in soybean breeding for modified saturated fatty acid profiles. A population of recombinant inbred lines derived from the cross of SD02-4-59?×?A02-381100 was grown in five environments and the seed samples from each environment were evaluated for fatty acid content. Genotyping of the population was performed with 516 polymorphic single nucleotide polymorphism markers and 298 polymorphic simple sequence repeat markers. Eight QTL for palmitic acid, five QTL for stearic acid and nine QTL for total saturated fatty acids were detected by composite interval mapping and/or interval mapping, with a high level of consistency or repeatability in multiple environments. Most of these QTL have not been reported previously, with the exception of qPAL-A1 which confirmed the result of a previous study. Significant QTL?×?QTL interactions were not detected. However, significant QTL?×?environment interactions were detected in most cases. Comparisons of two-locus and three-locus combinations indicated that cumulative effects of QTL were significant for both palmitic and stearic acids. QTL pyramiding by molecular marker-assisted selection would be an appropriate strategy for improvement of saturated fatty acids in soybean.     

Analysis of the total oil and fatty acid composition of seeds of some Boraginaceae taxa from Turkey

Mature seed samples of twenty-four Boraginaceae taxa collected from their natural habitats in Turkey were analysed by GC for total oil content and fatty acid composition. The range of total fat in the taxa varied between 7.0 and 35.7%. The amounts of palmitic (16:0) and stearic (18:0) acids determined were 5.65–17.81 and 1.49–5.08%, respectively. Mono-unsaturated fatty acids were in the range 8.83–55.32% for oleic, 0.22–6.21% for eicosenoic, 0.04–8.94% for erucic, and 0.08–2.71% for nervonic acid. Poly-unsaturated fatty acids were between 1.41 and 68.44% for linoleic, 0.12 and 43.0% for α-linolenic, 0.04 and 24.03% for γ-linolenic, and 0.02 and 14.59% for stearidonic acid. Total saturated (9.3–23.7%), mono-unsaturated (10.59–73.28%), and poly-unsaturated fatty acids (13.91–68.78%) varied substantially. Total unsaturated fatty acids ranged from 70.12 to 90.29%. There were significant differences between fatty acid profiles at taxa (P < 0.05) at genera levels, based on mono-unsaturated and poly-unsaturated fatty acid concentrations (P < 0.05). Segregation at the generic level by principle-component analysis was accomplished based on nine major fatty acids. The fatty acid patterns, their relative proportions, and quantities of unusual fatty acids as additional biochemical markers seem to be useful in the taxonomy of Boraginaceae at generic and infrageneric levels. All taxa are, in general, rich in linoleic and α-linolenic acids as essential fatty acids for dietary reference intakes. Seed oils of Symphytum, Anchusa, and Trachystemon orientalis for γ-linolenic acid and Echium for both γ-linolenic and stearidonic acid may be evaluated as alternative wild sources.     

脂肪酸对红火蚁搬尸行为的影响

【目的】工蚁死亡后易受病原菌的侵染,进而危害蚁巢的健康。为了避免病菌横向传播,活工蚁根据尸体体内特定的化学物质的变化来识别尸体并将其搬运到弃尸堆。本实验旨在研究6种脂肪酸(油酸、亚油酸、棕榈油酸、棕榈酸、硬脂酸和肉豆蔻酸)对红火蚁Solenopsis invicta工蚁搬尸行为的影响,明确不同脂肪酸在其搬尸行为中发挥的作用。【方法】本实验利用GC-MS分析了工蚁活体和尸体提取物的脂肪酸成分,并在室内用滤纸片法测定了红火蚁对6种脂肪酸(10 μg/μL)、不同浓度(0.75和3 μg/μL)的单组分油酸或亚油酸以及不同浓度(0.01, 0.1, 1和10 μg/μL)的这两种酸的混合液的反应。【结果】结果表明,红火蚁尸体仅含有亚油酸和油酸两种脂肪酸;另外4种脂肪酸(棕榈油酸、棕榈酸、硬脂酸和肉豆蔻酸)对红火蚁的搬尸行为无显著影响;单组分的油酸和亚油酸均能促进红火蚁的搬尸行为,浓度越高,搬尸行为越显著。10 μg/μL的油酸和亚油酸混合液对工蚁的搬尸行为也具有显著的促进效果,低浓度的混合液对其无明显的促进作用(P>0.05)。【结论】结果提示油酸和亚油酸可调控红火蚁的搬尸行为,其他脂肪酸对红火蚁搬尸行为不产生影响。     

Molecular basis of the high-palmitic acid trait in sunflower seed oil

Sunflower (Helianthus annuus L.) seed oil with high palmitic acid content has enhanced thermo-oxidative stability, which makes it well suited to high-temperature uses. CAS-5 is a sunflower mutant line that accumulates over 25 % palmitic acid in its seed oil, compared to 5–8 % in conventional cultivars. The objective of this study was to investigate the molecular basis of the high-palmitic acid trait in CAS-5 through both candidate gene and QTL mapping approaches. An F₂ population derived from the cross between CAS-5 and the conventional line HA-89 was developed. A 3-ketoacyl-ACP synthase II (KASII) locus on a telomeric region of linkage group (LG) 9 of the sunflower genetic map was found to co-segregate with palmitic acid content in this population. The KASII locus explained the vast majority of the phenotypic variation (98 %) of the trait. Two minor QTL affecting palmitic acid content were also found on the lower half of LG 9 and on LG 17. Additionally, QTL associated with other major fatty acids (stearic, oleic, and linoleic acid) were identified on LG 1, 6, and 10. This result may reflect untapped genetic variation that could exist among sunflower cultivars for genes determining fatty acid composition. In addition to demonstrating the major role of a KASII locus in the accumulation of high levels of palmitic acid in CAS-5 seeds, this study stressed the importance of characterizing genes with minor effects on fatty acid profile in order to establish optimal breeding strategies for modifying fatty acid composition in sunflower seed oil.