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1.
Many plant species produce volatile organic compounds after being damaged by herbivores. The production of volatiles also may be induced by exposing plants to the plant hormone, jasmonic acid, or its volatile ester, methyl jasmonate. This study addresses the induction of the production volatile organic compounds among genetic lines of Datura wrightii. Within populations, some plants produce glandular trichomes, whereas others produce nonglandular trichomes, and trichome phenotype is controlled by a single dominant gene. Glandular trichomes not only confer resistance to some herbivorous insects, but they also inhibit many natural enemies of those herbivores. Because of the potential benefit of natural enemies that use volatile cues to find individuals of the non-glandular phenotype, it is reasonable to ask if plants of D. wrightii that differ in trichome morphology might produce different blends of volatile compounds. Volatile compounds were collected from eight genetic lines of plants that had been backcrossed for three generations. Volatiles were collected from pairs of sibling plants before and after insect damage or treatment with methyl jasmonate. Within each pair, one sib expressed glandular trichomes and the other expressed nonglandular trichomes. Overall, plants produced an array of at least 17 compounds, most of which were sesquiterpenes. Total production of volatiles increased from 3.9- to 16.2-fold among genetic lines after insect damage and from 3.6- to 32-fold in plants treated with methyl jasmonate. The most abundant compound was (E)-β-caryophyllene. This single compound comprised from 17 to 59% of the volatiles from insect-damaged plants and from 24 to 88% of the volatiles from plants treated with methyl jasmonate, depending upon genetic line. The production of (E)-β-caryophyllene by the original male parents of the eight genetic lines was significantly related to the mean production of their third-generation backcross progeny indicating that the variation in the production of (E)-β-caryophyllene was inherited. Blends did not differ qualitatively or quantitatively between sibs expressing glandular or nonglandular trichomes.  相似文献   

2.
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   

3.
Securidaca longepedunculata Fers (Polygalaceae) is commonly used as a traditional medicine in many parts of Africa as well as against a number of invertebrate pests, including insects infesting stored grain. The present study showed that S. longepedunculata root powder, its methanol extract, and the main volatile component, methyl salicylate, exhibit repellent and toxic properties to Sitophilus zeamais adults. Adult S. zeamais that were given a choice between untreated maize and maize treated with root powder, extract, or synthetic methyl salicylate in a four-way choice olfactometer significantly preferred the control maize. Methyl salicylate vapor also had a dose-dependant fumigant effect against S. zeamais, Rhyzopertha dominica, and Prostephanus truncates, with a LD100 achieved with a 60 l dose in a 1-l container against all three insect species after 24 hr of exposure. Probit analyses estimated LD50 values between 34 and 36 l (95% CI) for all insect species. Furthermore, prolonged exposure for 6 days showed that lower amounts (30 l) of methyl salicylate vapor were able to induce 100% adult mortality of the three insect species. The implications are discussed in the context of improving stored product pest control by small-scale subsistence farmers in Africa.  相似文献   

4.
Macaranga myrmecophytes harbor species-specific Crematogaster ants that defend host trees from herbivores. We examined ant aggressive behaviors when artificially damaged leaf pieces from another tree were offered to four sympatric species of obligate Macaranga myrmecophytes. The ants showed aggressive behavior in response to leaf pieces regardless of the leaf species; however, aggressiveness was higher when conspecific leaf pieces were offered than when nonhost species were offered. Thus, ants can recognize leaf damage and distinguish among damaged leaf species. Chemical analyses of volatile compounds emitted from damaged leaves that may induce ant defense showed that the composition of the minor compounds differed among the four Macaranga species, although there were many compounds in common.  相似文献   

5.
This study was designed to address whether applications of methyl jasmonate (MJ) or Benzothiadiazole (BTH) to cultivated tomato, Lycopersicon esculentum, induced elevated densities of defense-related glandular trichomes on new leaves. Four-leaf tomato plants were sprayed with MJ, BTH, or control solutions, and the density of type VI glandular trichomes on new leaves was subsequently determined at 3, 7, 14, 21, and 28 d. At 7, 14, and 21 d, the density of type VI glandular trichomes on new leaves was significantly higher on MJ-treated plants than on BTH- or control-treated plants. At 7 and 14 d after treatment, the mean density of glandular trichomes on new leaves of MJ-treated plants was ninefold higher than on leaves of control-treated plants. We observed entrapment of immature western flower thrips in trichomes on MJ-treated plants at higher rates than on BTH or control plants. Studies to evaluate potential trade-offs between reductions in pest populations by increased trichome density and possible negative impacts of trichome induction on biological control agents are needed.  相似文献   

6.
Larvae of the pipevine swallowtail, Battus philenor, feed on plants in the genus Aristolochia, which contains aristolochic acids, toxic alkaloids unique to the Aristolochiaceae. Pipevine swallowtails sequester these compounds and, as a consequence, are chemically defended against many natural enemies. In California, the primary aristolochic acid present in the butterfly is aristolochic acid I. Newly eclosed adult females possess greater amounts of these sequestered toxins compared to males. However, over the course of the flight season, the aristolochic acid content of females in the population declines, whereas male aristolochic acid content remains relatively constant. Transference of sequestered aristolochic acids to eggs by females might explain the decline of these sequestered chemical defenses observed over time. We found no evidence that males transfer aristolochic acids to females via the spermatophore. The possibility that females at the end of the flight season may be automimics of males is discussed. Temporal variation in the aristolochic acid defenses exhibited by this pipevine swallowtail population is both age- and sex-dependent.  相似文献   

7.
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   

8.
Goldenseal (Hydrastis canadensis L.) is a popular medicinal plant distributed widely in North America. The rhizome, rootlets, and root hairs produce medicinally active alkaloids. Berberine, one of the Hydrastis alkaloids, has shown antifungal activity. The influence of a combination of the major Hydrastis alkaloids on the plant rhizosphere fungal ecology has not been investigated. A bioassay was developed to study the effect of goldenseal isoquinoline alkaloids on three Fusarium isolates, including the two species isolated from Hydrastis rhizosphere. The findings suggest that the Hydrastis root extract influences macroconidia germination, but that only the combined alkaloids—berberine, canadine, and hydrastine—appear to synergistically stimulate production of the mycotoxin zearalenone in the Fusarium oxysporum isolate. The Hydrastis root rhizosphere effect provided a selective advantage to the Fusarium isolates closely associated with the root tissue in comparison with the Fusarium isolate that had never been exposed to Hydrastis.  相似文献   

9.
Natural populations of Datura wrightii in southern California are dimorphic for trichome type. Some plants within populations produce greater than 85% glandular trichomes, whereas other produce mainly nonglandular trichomes. Glandular trichome exudates in D. wrightii consist of glucose esterified with straight chain C6–C9 acids. These exudates, and similar exudates in other species, confer resistance to several insect herbivore species. We tested the hypothesis that water was limiting sugar ester production and examined the extent to which trichome density was determined by environmental factors by measuring the concentrations of sugar esters and the densities of trichomes on leaves of plants grown under different irrigation treatments. Water did not limit sugar ester production, as unwatered plants produced 36% more millimoles of glucose esters per square centimeter of leaf surface than did watered plants. Although the addition of water increased leaf size, densities of both nonglandular and glandular trichomes did not change with leaf length or area, suggesting that plants having larger leaves initiated more trichomes in order to maintain nearly constant densities. Millimoles of sugar esters produced did not correlate with densities of glandular trichomes, suggesting that other factors in addition to glandular trichome number govern the production of sugar esters for plant defense.  相似文献   

10.
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   

11.
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   

12.
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   

13.
Avato P  Rosito I  Papadia P  Fanizzi FP 《Lipids》2005,40(10):1051-1056
As a continuation of our study on plants of the Sapindaceae, the chemical composition of the oil extracted from seeds of Allophylus natalensis (Sonder) De Winter and of A. dregeanus (Sonder) De Winter has been investigated. The oil from both species contained approximately equal amounts of TAG and type I cyanolipids (CL), 1-cyano-2-hydroxymethylprop-2-en-1-oldiesters, with minor amounts of type III CL, 1-cyano-2-hydroxymethylprop-1-en-3-ol-diesters. Structural investigation of the oil components was accomplished by chemical, chromatographic (TLC, CC, GC, and GC-MS), and spectroscopic (IR, NMR) means. GC and GC-MS analysis showed that C20 FA were dominant in the CL components of the oil from the two species (44–80% vs. 21–26% in TAG), with cis-11-eicosenoic acid (36–46%) and cis 13-eicosenoic acid (paullinic acid, 23–37%) as the major esterified fatty acyl chains in A. natalensis and A. dregeanus, respectively. cis-Vaccenic acid was particularly abundant (11–31%) in the CL from A. dregeanus, whereas eicosanoic acid (10–22%) was also a major component of CL in both species.  相似文献   

14.
Many parasitic nematodes have an environmental infective stage that searches for hosts. Olfaction plays an important role in this process, with nematodes navigating their environment using host-emitted and environmental olfactory cues. The interactions between parasitic nematodes and their hosts are also influenced by the olfactory behaviors of the host, since host olfactory preferences drive behaviors that may facilitate or impede parasitic infection. However, how olfaction shapes parasite-host interactions is poorly understood. Here we investigated this question using the insect-parasitic nematode Howardula aoronymphium and its host, the mushroom fly Drosophila falleni. We found that both H. aoronymphium and D. falleni are attracted to mushroom odor and a subset of mushroom-derived odorants, but they have divergent olfactory preferences that are tuned to different mushroom odorants despite their shared mushroom environment. H. aoronymphium and D. falleni respond more narrowly to odorants than Caenorhabditis elegans and Drosophila melanogaster, consistent with their more specialized niches. Infection of D. falleni with H. aoronymphium alters its olfactory preferences, rendering it more narrowly tuned to mushroom odor. Our results establish H. aoronymphium-D. falleni as a model system for studying olfaction in the context of parasite-host interactions.  相似文献   

15.
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   

16.
Primary plant surfaces, covered with cuticles consisting of cutin and waxes, are important substrates for interaction with insects. The composition of leaf surfaces of the myrmecophilic plant Macaranga tanarius was studied. The prenylated flavanone nymphaeol-C was identified in surface extracts and was localized exclusively in glandular trichomes on the abaxial leaf side. The epidermal pavement cells surrounding these trichomes were covered with a smooth film of epicuticular wax from which few small wax crystals protruded. The epicuticular wax amounted to approximately 8 μg cm−2, corresponding to 85% of the wax load on the adaxial as well as the abaxial leaf sides. The epicuticular wax mixtures from both leaf surfaces contained more than 70% primary alcohols, 14% fatty acids, 2% aldehydes, and traces of alkyl acetates, with chain lengths ranging from C20 to C38. In contrast, the intracuticular wax layer was largely dominated by triterpenoid alcohols α-amyrin, β-amyrin, and lupeol. Consequently, these characteristic compounds are not available for direct contact with insects on the plant surface.  相似文献   

17.
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   

18.
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   

19.
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   

20.
Two tunicates (Fudistoma bituminis and Cystodytes violatinctus, family Polycitoridae) were investigated for the FA content of their phospholipids. GC-MS analysis of their methyl esters and N-acyl pyrrolidides revealed 40 FA in E. bituminis, and 26 in C. violatinctus. In both cases, the most abundant FA were the saturated ones (C10 to C18). Cystodytes violatinctus contained considerable oleic acid (20%). Both E. bituminis and C. violatinctus contained phytanic acid and Δ10-unsaturated FA, which had not previously been found in such organisms. The two tropical tunicates contained only trace amounts of PUFA, which are usually predominant in this phylum.  相似文献   

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