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1.
A new fatty acid, (5Z,9Z)-22-methyl-5,9-tetracosadienoic acid (1a), and a rare fatty acid, (5Z,9Z)-23-methyl-5,9-tetracosadienoic acid (2a), the predominant constituents of the free fatty acid fraction from the lipids of the sponge Geodinella robusta, were isolated and partly separated by reversed phase high-performance liquid chromatography, followed by multifold crystallization from MeOH to give 1a and 2a in 70% and 60% purity, respectively. These fatty acids were identified as (5Z,9Z)-22-and (5Z,9Z)-23-methyl-5,9-tetracosadienoic acids by nuclear magnetic resonance techniques, including distortionless enhancement by polarization transfer, heteronuclear multiple quantum connectivity, and correlation spectroscopy experiments, as well as from mass-spectrometric data for their methyl esters, the methyl esters of their perhydro derivatives, and their pyrrolidides. Mixtures of 1a and 2a showed cytotoxic activity against mouse Ehrlich carcinoma cells and a hemolytic effect on mouse erythrocytes. The sterol fraction from the same sponge was analyzed by gas liquid chromatography mass spectrometry, and 24-methylenecholesterol was identified as a main constituent of this fraction. The implications of the co-occurrence of membranolytic long-chain fatty acids and 24-methylenecholesterol as a main membrane sterol are discussed in terms of the phenomenon of biochemical coordination.  相似文献   

2.
Imbs AB  Rodkina SA 《Lipids》2005,40(9):963-968
Reinvestigation of the current FA composition of the regional freshwater sponge Baicalospongia bacillifera showed that the main measured isomer of EPA (14% of the total FA now detected) is, in fact, an unusual 5Z,8Z,11Z,14Z,18E-EPA. Two other isomers of this acid also present were identified as a novel 5Z,8Z,11Z,15Z,18E-EPA and the common methylene-interrupted 5Z,8Z,11Z,14Z,17Z-EPA (usually written simply as EPA). Isolation of these acids as their methyl ester derivatives was accomplished with the use of a combination of silver-ion column chromatography and HPLC. The structure of the two new compounds was deduced from GC-MS and detailed NMR data. Partial hydrazine reduction of all three isolated EPA esters followed by separation of cis/trans isomers of the resulting monoenoic acids and GC-MS analysis of their dimethyl disulfide adducts were used for determination of the configuration and position of the double bonds. We may assume that the sponge B. bacillifera cannot receive these unusual EPA isomers directly from food sources (e.g., algal diatoms), and accordingly restructuring of ordinary EPA to novel acids may take place in the sponge tissue.  相似文献   

3.
The sandalwood kernels of Santalum insulare (Santalaceae) collected in French Polynesia give seed oils containing significant amounts of ximenynic acid, E-11-octadecen-9-oic acid (64–86%). Fatty acid (FA) identifications were performed by gas chromatography/mass spectrometry (GC/MS) of FA methyl esters. Among the other main eight identified fatty acids, oleic acid was found at a 7–28% level. The content in stearolic acid, octadec-9-ynoic acid, was low (0.7–3.0%). An inverse relationship was demonstrated between ximenynic acid and oleic acid using 20 seed oils. Results obtained have been compared to other previously published data on species belonging to the Santalum genus, using multivariate statistical analysis. The relative FA S. insulare composition, rich in ximenynic acid is in the same order of those given for S. album or S. obtusifolium. The other compared species (S. acuminatum, S. lanceolatum, S. spicatum and S. murrayanum) are richer in oleic acid (40–59%) with some little differences in linolenic content.  相似文献   

4.
Derivatives of 2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid (chrysanthemic acid) are classic natural pyrethroids discovered in pyrethrum plants and show insecticidal activity. Chrysanthemic acid, with two asymmetric carbons, has four possible stereoisomers, and most natural pyrethroids have the (1R,3R)-trans configuration. Interestingly, chrysanthemic acid–related structures are also found in insect sex pheromones; carboxylic esters of (1R,3R)-trans-(2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropyl)methanol (chrysanthemyl alcohol) have been reported from two mealybug species. In the present study, another ester of chrysanthemyl alcohol was discovered from the striped mealybug, Ferrisia virgata (Cockerell), as its pheromone. By means of gas chromatography–mass spectrometry, nuclear magnetic resonance spectrometry, and high-performance liquid chromatography analyses using a chiral stationary phase column and authentic standards, the pheromone was identified as (1S,3R)-(?)-cis-chrysanthemyl tiglate. The (1S,3R)-enantiomer strongly attracted adult males in a greenhouse trapping bioassay, whereas the other enantiomers showed only weak activity. The cis configuration of the chrysanthemic acid–related structure appears to be relatively scarce in nature, and this is the first example reported from arthropods.  相似文献   

5.
Poly(ethylene oxide)-block-poly(butyl acrylate) copolymers were prepared via simplified electrochemically mediated atom transfer radical polymerization (seATRP) utilizing only 1 ppm of CuII complex, which is the limit of a successful well-controlled polymerization. The presented seATRP system works under potentiostatic and galvanostatic conditions. The polymerization results showed similar molecular weight evolution while maintaining a narrow molecular weight distribution throughout the reactions. 1H NMR results confirm chemical structure of synthesized diblock copolymers. This ultralow ppm technique is promising candidate for polymerization from nanoparticles, flat surfaces, proteins, and DNA.  相似文献   

6.
E-2-ethyl-2-hexen-1-ol (1), mellein (4), and 4-hydroxymellein (5) were identified as the major volatile compounds in the head and/or thorax of Camponotus quadrisectus. Neither 1 nor 5 have been previously detected in insects. Also identified were small amounts of m-cresol (2) and 6-methyl salicylic acid (3). E-2-ethylhexenal (6) and small amounts of 3 were identified in heads of Camponotus irritibilis from Kuala Belalong, Brunei. Compounds 24 occur in other Bornean camponotines with hypertrophied mandibular glands, and 4 is widespread in the tribe. The possibility of semiochemical parsimony (multiple functions) for these mandibular gland compounds is reviewed in the context of existing data on mandibular gland products of other camponotines, reported biological activities of the compounds, and secondary loss of metapleural glands in this ant group.  相似文献   

7.
Few studies report the individual effect of 9c,11t- and 10t,12c-CLA on human energy metabolism. We compared the postprandial oxidative metabolism of 9c,11t- and 10t,12c-CLA and oleic acid (9c-18:1) in 22 healthy moderately overweight volunteers. After 24 weeks supplementation with 9c,11t-, 10t,12c-CLA or 9c-18:1 (3 g/day), subjects consumed a single oral bolus of the appropriate [1-13C]-labeled fatty acid. 8 h post-dose, cumulative oxidation was similar for 9c-18:1 and 10t,12c (P = 0.66), but significantly higher for 9c,11t (P < 0.01).  相似文献   

8.
A new class of polymeric acidic ionic liquids with imidazolium hydrogen sulfate and p-phenylene sulfonic acid units built into the main polymer chain were prepared by a simple two step method in 87–89% yield. These new polymers were characterized by elemental analysis, 1H, 13C NMR, FT-IR, TGA and GPC. The catalytic activity of sulfonic acid group functionalized ionic liquid polymers was demonstrated through the synthesis of 1-amidoalkyl-2-naphthols in 78–90% yield by condensation of 2-naphthol, benzaldehyde and amides without a solvent at 100 °C.  相似文献   

9.
In this study, we synthesized the new kinds of semiconducting polymeric gels having negative (n-type) and positive (p-type) counter ions as charge carriers. The polyacrylamide gel was doped with pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid, trisodium salt), having \textSO3 - {\text{SO}}_{3}^{ - } ions as side groups and Na+ as counter ions, so-called p-type semiconducting gel. The doping process was performed during the polymerization where the pyranine binds to the polymer strands over OH group chemically via radical addition. In a similar way, N-isopropylacrylamide (NIPA) gel was doped with methacrylamidopropyltrimethyl ammonium chloride (MAPTAC), having Cl as counter ions, so-called n-type semiconducting gel. Here MAPTAC was embedded by copolymerization within the polymer network (NIPA). These semiconducting gels can show different electrical properties by changing the concentration of the doping agents, swelling ratio etc. We have shown that the pn junction, formed by combining p-type and n-type gels together in close contact, rectifies the current similar to the conventional Si and Ge diodes.  相似文献   

10.
The hydrocarbons (3Z,6Z,9Z)-3,6,9-octadecatriene (3Z,6Z,9Z-18:H) and (3Z,6Z,9Z)-3,6,9-nonadecatriene (3Z,6Z,9Z-19:H) constitute the pheromone of the winter moth, Erannis bajaria. These compounds belong to a large group of lepidopteran pheromones which consist of unsaturated hydrocarbons and their corresponding oxygenated derivatives. The biosynthesis of such hydrocarbons with an odd number of carbons in the chain is well understood. In contrast, knowledge about the biosynthesis of even numbered derivatives is lacking. We investigated the biosynthesis of 3Z,6Z,9Z-18:H by applying deuterium-labeled precursors to females of E. bajaria followed by gas chromatography–mass spectrometry analysis of extracts of the pheromone gland. A mixture of deuterium-labeled [17,17,18,18-2H4]-3Z,6Z,9Z-18:H and the unlabeled 3Z,6Z,9Z-18:H was obtained after topical application and injection of (10Z,13Z,16Z)-[2,2,3,3-2H4]-10,13,16-nonadecatrienoic acid ([2,2,3,3-2H4]-10Z,13Z,16Z-19:acid) or (11Z,14Z,17Z)-[3,3,4,4-2H4]-11,14,17-icosatrienoic acid ([3,3,4,4-2H4]-11Z,14Z,17Z-20:acid). These results are consistent with a biosynthetic pathway that starts with α-linolenic acid (9Z,12Z,15Z-18:acid). Chain elongation leads to 11Z,14Z,17Z-20:acid, which is shortened by α-oxidation as the key step to yield 10Z,13Z,16Z-19:acid. This acid can be finally reduced to an aldehyde and decarbonylated or decarboxylated to furnish the pheromone component 3Z,6Z,9Z-18:H. A similar transformation of 11Z,14Z,17Z-20:acid yields the second pheromone component, 3Z,6Z,9Z-19:H.  相似文献   

11.
The autoxidation processes of the cis-9,trans-11 (c9,t11) and trans-10,cis-12 (t10,c12) isomers of CLA were separately observed at ca. 0% RH and different temperatures. The t10,c12 CLA oxidized faster than the c9,t11 isomer at all tested temperatures. The first half of the oxidation process of t10,c12 CLA obeyed an autocatalytic-type rate expression, but the latter half followed first-order kinetics. On the other hand, the entire oxidation process of c9,t11 CLA could be expressed by the autocatalytic-type rate expression. The apparent activation energies and frequency factors for the autoxidation of the isomers were estimated from the rate constants obtained at various temperatures based on the Arrhenius equation. The apparent activation energies for the CLA isomers were greater than those for the nonconjugated n−6 and n−3 PUFA or their esters. However, the enthalpyentropy compensation held during the autoxidation of both the CLA and PUFA. This suggested that the autoxidation mechanisms for the CLA and PUFA were essentially the same.  相似文献   

12.
Locoweeds (Astragalus and Oxytropis spp. that contain the toxic alkaloid swainsonine) cause widespread poisoning of livestock on western rangelands. There are 354 species of Astragalus and 22 species of Oxytropis in the US and Canada. Recently, a fungal endophyte, Embellisia spp., was isolated from Astragalus and Oxytropis spp. and shown to produce swainsonine. We conducted a survey of the major locoweeds from areas where locoweed poisoning has occurred to verify the presence of the endophyte and to relate endophyte infection with swainsonine concentrations. Species found to contain the fungal endophyte and produce substantial amounts of swainsonine were A. wootoni, A. pubentissimus, A. mollissimus, A. lentiginosus, and O. sericea. Astragalus species generally had higher concentrations of swainsonine than Oxytropis. Swainsonine was not detected in A. alpinus, A. cibarius, A. coltonii, A. filipes, or O. campestris. The endophyte could not be cultured from A. mollissimus var. thompsonii or A. amphioxys, but was detected by polymerase chain reaction, and only 30% of these samples contained trace levels of swainsonine. Further research is necessary to determine if the endophyte is able to colonize these and other species of Astragalus and Oxytropis and determine environmental influences on its growth and synthesis of swainsonine.  相似文献   

13.
In batch chromatography, solvent-gradient operations (SG) produce significant improvement in terms of the enrichment of products and the separation time and the solvent consumption as compared with isocratic operations. This work studied solvent-gradient operation in reversed-phase simulated moving bed unit to separate ortho-xylene and para-xylene. In a solvent-gradient mode, different mobile phase compositions lead to a different retention behavior of solutes, i.e., different adsorption isotherms. Frontal analysis experiments for ortho-xylene and para-xylene were carried out with a reversed-phase column to measure adsorption parameters at several different mobile phase compositions, such as 45%, 50%, 60%, 75% and 90% acetonitrile. Therefore, the parameters in the retention model for solvent-gradient operation in the case of reversed-phase chromatography were estimated and applied to the design of an SMB system. A modified design method for solvent-gradient simulated moving bed chromatography (SG-SMB) was proposed. The robust operating conditions were obtained within the separation region on (φ R , φ E ) plane (φ R and φ E are the volumetric content of organic modifier in the raffinate and the extract streams, respectively). The performance results of isocratic and solvent-gradient SMB were compared. A partial-discard strategy and increasing of the solvent gradient level were also applied to improve the performance of the SG-SMB.  相似文献   

14.
Ethanolic extract of aerial parts of Artemisia annua L. and artemisinin were evaluated as anti-insect products. In a feeding deterrence assay on Epilachna paenulata Germ (Coleoptera: Coccinellidae) larvae, complete feeding rejection was observed at an extract concentration of 1.5 mg/cm2 on pumpkin leaf tissue. The same concentration produced a feeding inhibition of 87% in Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae). In a no-choice assay, both species ate less and gained less weight when fed on leaves treated with the extract. Complete mortality in E. paenulata and 50% mortality in S. eridania were observed with extract at 1.5 mg/cm2. Artemisinin exhibited a moderate antifeedant effect on E. paenulata and S. eridania at 0.03–0.375 mg/cm2. However, a strong effect on survival and body weight was observed when E. paenulata larvae were forced to feed on leaves treated at 0.03 and 0.075 mg/cm2. Artemisia annua ethanolic extract of aerial parts at 1.5 mg/cm2 showed no phytotoxic effect on pumpkin seedlings.  相似文献   

15.
Rezanka T  Siristova L  Melzoch K  Sigler K 《Lipids》2011,46(3):249-261
Identification of molecular species of various N-acylated bacteriohopanehexol-mannosamides from the thermophilic bacterium Alicyclobacillus acidoterrestris by semipreparative HPLC and by RP-HPLC with ESI is described. We used triple-quadrupole type mass spectrometer, 1H and 13C NMR for analyzing this complex lipid. CD spectra of two compounds (model compound—7-deoxy-d-glycero-d-allo-heptitol obtained by stereospecific synthesis, and an isolated derivative of hopane) were also measured and the absolute configuration of both compounds was determined. On the basis of all the above methods, we identified the full structure of a new class of bacteriohopanes, represented by various N-acylated bacteriohopanehexol-mannosamides.  相似文献   

16.
A series of N-allyl, N-ethylmethacrylate and N-phenylmethacrylatenaphthalimide monomers have been prepared with –C=CFc, –C≡CFc and –C≡CSiMe3 substituents at the 4-position of the naphthalimide ring. All have been characterised by elemental analysis and spectroscopy; the X-ray structure of N-allyl-4-ethenylferrocenylnapththalimide is also reported. Free-radical polymerisation of these monomers gave homopolymers, random co- and terpolymers with polydispersities ranging from 1.7 to 3.2. Incorporation into a polymer matrix has no effect on the spectroscopic and electrochemical properties of the naphthalimide or ferrocenyl components. The ferrocenyl polymers are electrochromic and when oxidised give naphthalimide charge-transfer bands in the NIR; this electrochromism was examined by OTTLE techniques.  相似文献   

17.
Nitroso compounds were electrogenerated from (1S, 2S)-2-amino-1-(4-nitrophenyl)-propane-1,3-diol derivatives (derivatives of p-nitrophenylserinol) in a “redox” flow cell equipped with two consecutive porous electrodes of opposite polarities. In spite. of the relative instability in methanol-acetate buffer of the hydroxylamine intermediates produced at the first porous electrode (cathode), the nitroso derivatives were prepared in good yields at the second one (anode). A coupling reaction between some nitroso derivatives and p-toluenesulphinic acid led to N-sulphonylphenylhydroxylamines.  相似文献   

18.
N‐Dodecyl‐N,N‐di(2‐hydroxyethyl) amine oxide (C12DHEAO) and N‐stearyl‐N,N‐di(2‐hydroxyethyl) amine oxide (C18DHEAO) were synthesized with N‐alkyl‐diethanolamine and hydrogen peroxide. Their chemical structures were confirmed using 1H‐NMR spectra, mass spectral fragmentation and FTIR spectroscopic analysis. It was found that C12DHEAO and C18DHEAO reduced the surface tension of water to a minimum value of approximately 28.75 mN m?1 at concentration of 2.48 × 10?3 mol L?1 and 32.45 mN m?1 at concentration of 5.21 × 10?5 mol L?1, respectively. The minimum interfacial tension (IFTmin) and the dynamic interfacial tension (DIT) of oil–water system were measured. When C18DHEAO concentration was in the range of 0.1–0.5%, the IFTmin between liquid paraffin and C18DHEAO solutions all reached the ultra‐low interfacial tension. Furthermore, their foam properties were investigated by Ross‐Miles method, and the height of foam of C12DHEAO was 183 mm. It was also found that they showed strong emulsifying power.  相似文献   

19.
Ophrys flowers mimic sex pheromones of attractive females of their pollinators and attract males, which attempt to copulate with the flower and thereby pollinate it. Virgin females and orchid flowers are known to use the same chemical compounds in order to attract males. The composition of the sex pheromone and its floral analogue, however, vary between pollinator genera. Wasp-pollinated Ophrys species attract their pollinators by using polar hydroxy acids, whereas Andrena-pollinated species use a mixture of non-polar hydrocarbons. The phylogeny of Ophrys shows that its evolution was marked by episodes of rapid diversification coinciding with shifts to different pollinator groups: from wasps to Eucera and consequently to Andrena and other bees. To gain further insights, we studied pollinator attraction in O. leochroma in the context of intra- and inter-generic pollinator shifts, radiation, and diversification in the genus Ophrys. Our model species, O. leochroma, is pollinated by Eucera kullenbergi males and lies in the phylogeny between the wasp and Andrena-pollinated species; therefore, it is a remarkable point to understand pollinator shifts. We collected surface extracts of attractive E. kullenbergi females and labellum extracts of O. leochroma and analyzed them by using gas chromatography with electroantennographic detection (GC-EAD) and gas chromatography coupled with mass spectrometry (GC-MS). We also performed field bioassays. Our results show that O. leochroma mimics the sex pheromone of its pollinator’s female by using aldehydes, alcohols, fatty acids, and non-polar compounds (hydrocarbons). Therefore, in terms of the chemistry of pollinator attraction, Eucera-pollinated Ophrys species might represent an intermediate stage between wasp- and Andrena-pollinated orchid species.  相似文献   

20.
Yellow-cedar, Callitropsis nootkatensis, is prevalent in coastal forests of southeast Alaska, western Canada, and inland forests along the Cascades to northern California, USA. These trees have few microbial or animal pests, attributable in part to the distinct groups of biologically active secondary metabolites their tissues store for chemical defense. Here we summarize the new yellow-cedar compounds identified and their biological activities, plus new or expanded activities for tissues, extracts, essential oils and previously known compounds since the last review more than 40 years ago. Monoterpene hydrocarbons are the most abundant compounds in foliage, while heartwood contains substantial quantities of oxygenated monoterpenes and oxygenated sesquiterpenes, with one or more tropolones. Diterpenes occur in foliage and bark, whereas condensed tannins have been isolated from inner bark. Biological activities expressed by one or more compounds in these groups include fungicide, bactericide, sporicide, acaricide, insecticide, general cytotoxicity, antioxidant and human anticancer. The diversity of organisms impacted by whole tissues, essential oils, extracts, or individual compounds now encompasses ticks, fleas, termites, ants, mosquitoes, bacteria, a water mold, fungi and browsing animals. Nootkatone, is a heartwood component with sufficient activity against arthropods to warrant research focused toward potential development as a commercial repellent and biopesticide for ticks, mosquitoes and possibly other arthropods that vector human and animal pathogens.  相似文献   

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