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1.
Coccinellid beetles contain a variety of defensive alkaloids that render them unpalatable to predators. Epilachna paenulata (Coleoptera: Coccinellidae) is a South American ladybird beetle that feeds on plants of the Cucurbitaceae family. The defensive
chemistry of E. paenulata has been characterized as a mixture of systemic piperidine, homotropane, and pyrrolidine alkaloids. Whole body extracts of
adult beetles contain four major alkaloids: 2-(2′-oxopropyl)-6-methylpiperidine (1); 1-(6-methyl-2,3,4,5-tetrahydro-pyridin-2-yl)-propan-2-one (2); 1-methyl-9-azabicyclo[3.3.1]nonan-3-one (3); and 1-(2″-hydroxyethyl)-2-(12′-aminotridecyl)-pyrrolidine (4). Comparative studies of the defensive chemistry of eggs, larvae, pupae, and adults showed differences in alkaloid composition
and concentration among life stages. While adults contained mainly the homotropane 1-methyl-9-azabicyclo[3.3.1]nonan-3-one
(3), eggs showed the highest concentration of the piperidine 2-(2′-oxopropyl)-6-methylpiperidine (1). We studied the origin of this alkaloid in the eggs by feeding newly emerged, virgin adult beetles with [2-13C]-labeled acetate, and by performing crosses between 13C-fed and unlabeled males and females. GC-MS analysis of alkaloids from 13C-fed males and females showed high incorporation of 13C into the alkaloids, as evidenced from a 20–30% increase of isotopic peaks in diagnostic fragment ions, confirming the expected
endogenous origin of these alkaloids. In addition, analyses of eggs from different crosses showed that labeled alkaloids from
both parents are incorporated into eggs, indicating that E. paenulata males transfer alkaloids to the females at mating. Biparental endowment of chemical defenses into eggs has been shown previously
in insects that acquire defensive compounds from dietary sources. To our knowledge, this is the first report of biparental
egg endowment of endogenous defenses.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
Kirsten A. Leiss Young H. Choi Ibrahim B. Abdel-Farid Robert Verpoorte Peter G. L. Klinkhamer 《Journal of chemical ecology》2009,35(2):219-229
Western flower thrips (Frankliniella occidentalis) has become a key insect pest of agricultural and horticultural crops worldwide. Little is known about host plant resistance
to thrips. In this study, we investigated thrips resistance in F
2 hybrids of Senecio jacobaea and Senecio aquaticus. We identified thrips-resistant hybrids applying three different bioassays. Subsequently, we compared the metabolomic profiles
of these hybrids applying nuclear magnetic resonance spectroscopy (NMR). The new developments of NMR facilitate a wide range
coverage of the metabolome. This makes NMR especially suitable if there is no a priori knowledge of the compounds related
to herbivore resistance and allows a holistic approach analyzing different chemical compounds simultaneously. We show that
the metabolomes of thrips-resistant and -susceptible hybrids differed considerably. Thrips-resistant hybrids contained higher
amounts of the pyrrolizidine alkaloids (PA), jacobine, and jaconine, especially in younger leaves. Also, a flavanoid, kaempferol
glucoside, accumulated in the resistant plants. Both PAs and kaempferol are known for their inhibitory effect on herbivores.
In resistant and susceptible F
2 hybrids, young leaves showed less thrips damage than old leaves. Consistent with the optimal plant defense theory, young
leaves contained increased levels of primary metabolites such as sucrose, raffinose, and stachyose, but also accumulated jacaranone
as a secondary plant defense compound. Our results prove NMR as a promising tool to identify different metabolites involved
in herbivore resistance. It constitutes a significant advance in the study of plant–insect relationships, providing key information
on the implementation of herbivore resistance breeding strategies in plants.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
3.
Petr Žáček Blanka Kalinová Jan Šobotník Oldřich Hovorka Vladimír Ptáček Audrey Coppée François Verheggen Irena Valterová 《Journal of chemical ecology》2009,35(6):698-705
Age-related changes of antennal-active components of male labial gland extracts were studied in two closely related bumblebee
species, Bombus terrestris and B. lucorum. In B. terrestris, compounds eliciting electroantennogram (EAG) responses of virgin queens were ethyl dodecanoate, 2,3-dihydrofarnesal, 2,3-dihydrofarnesol,
hexadecan-1-ol, octadeca-9,12,15-trien-1-ol, and geranylcitronellol. Compounds that elicited EAG responses from queens of
B. lucorum were ethyl dodecanoate, ethyl tetradec-7-enoate, ethyl tetradec-9-enoate, ethyl hexadec-9-enoate, hexadecan-1-ol, hexadec-7-enal,
octadeca-9,12-dien-1-ol, octadeca-9,12,15-trien-1-ol, and octadecan-1-ol. Quantities of these compounds in the labial glands
changed significantly over the lifetime of the respective males of the two species. In both species, concentrations of the respective compounds reached their maximum within seven days after eclosion. Subsequently,
a rapid decrease in the amount of EAG-active compounds occurred in B. terrestris, whereas in B. lucorum the amount of active compounds stayed approximately constant or decreased at a slow rate. Microscopy showed that in B. terrestris secretory cells of the labial glands undergo apoptosis from the fifth to the tenth day of life, whilst in B. lucorum labial gland cells remain unchanged throughout the life of the males. 相似文献
4.
5.
Joshua Rodstein J. Steven McElfresh James D. Barbour Ann M. Ray Lawrence M. Hanks Jocelyn G. Millar 《Journal of chemical ecology》2009,35(5):590-600
Females of the large cerambycid beetle Prionus californicus produce a powerful sex pheromone that attracts males. The pheromone was adsorbed on solid phase microextraction (SPME) fibers
inserted into the ovipositor sheath and analyzed by coupled gas chromatography-electroantennogram detection and GC-mass spectrometry.
The pheromone was identified as an isomer of 3,5-dimethyldodecanoic acid by a combination of retention index comparisons and
mass spectral interpretation. The mass spectrum was misleading because it exhibited enlarged fragment ions that were not representative
of branch points or other obvious stabilizing structural elements. The structure was verified by synthesis of 3,5-dimethyldodecanoic
acid as a mixture of all four possible isomers, and this mixture was highly attractive to male beetles in field bioassays.
The SPME extracts also contained several other compounds that were tentatively identified as chain-extended homologs of the
main pheromone component. This pheromone should prove useful for sampling and management of the beetle, which is an important
pest of hops, and an occasional pest in a variety of orchard crops. Although this is the first female-produced pheromone to
be identified from the Cerambycidae, there is considerable evidence for pheromone production by females of other species in the subfamily Prioninae. Thus, this pheromone and the associated methodology used in its identification should be useful in the identification of
female-produced attractant pheromones from other members of the subfamily.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
6.
Dhanapalan Karthikeyan Nachiappan Lingappan Bommasamudram Sivasankar 《Korean Journal of Chemical Engineering》2008,25(5):987-997
Bifunctional catalysts containing (0.1–0.5 wt%) Nickel and 0.1 wt% of Pd supported on H-β zeolite were synthesized by incipient wetness impregnation method and characterized by XRD, TEM, XPS, TPD and TPR techniques.
The catalytic activity of Ni containing and Ni free Pd/H-β Catalysts was studied, and it was found that Ni up to a threshold value (0.3 wt% on β) produced increased the n-decane conversion and isomerization selectivity. When Ni content exceeds the threshold value, the
conversion increases but isomerized products decrease. Moreover, Ni containing Pd/H-β showed increased sustainability and favored the protonated cyclopropane (PCP) intermediate mechanism in n-decane isomerization.
The catalyst containing 0.3 wt% Ni 0.1 wt% Pd is adjudged as one performing better than other catalysts studied because of
the isomerized mixture from it shows better octane number. 相似文献
7.
The effects of key parameters on the preparation and regeneration of protoplast from the β-carotene-producing fungus Blakeslea trispora were discussed in this paper, including the combination of various enzymes, mycelial age, digesting time and temperature,
pH value, osmotic stabilizers, pretreatment, culture medium and culture method. Under the condition of mixed enzymes in osmotic
stabilizer (0.6 M NaCl) combined with 2% lysozyme, 3% cellulase and 3% snailase, the highest protoplast yield, as high as
7.48×106 protoplasts/mL, was obtained when mycelial age was 60 h at pH 5.0–6.0 with digesting for 14–16 h at 28 °C. After
purification of the obtained protoplasts, they were regenerated in PDA regenerative medium using bilayer plate culture method.
To validate the usability of the protoplasts, a novel plasmid with green fluorescent protein (GFP) was used in transformation
for easy visual observation. The results showed that the protoplasts prepared by the optimized method were active and applicable
in further gene manipulation experiments.
This work was presented at 13
th
YABEC symposium held at Seoul, Korea, October 20–22, 2007. 相似文献
8.
M. L. Ulanovskii 《Coke and Chemistry》2009,52(10):434-439
Analysis of the regression equations proposed for the prediction of coke quality on the basis of CSR and CRI shows that some equations with relatively high correlation coefficients produce results inconsistent with experimental data
and therefore require refinement. Equations that include characteristics calculated from the chemical composition of the ash
and the physical constants of the oxides present (the molecular mass, the actual density, the melting point) lead to large
errors and hence cannot be recommended. 相似文献
9.
Robert J. Bartelt Bruce W. Zilkowski Allard A. Cossé C. Dayton Steelman Narinderpal Singh 《Journal of chemical ecology》2009,35(4):422-434
The lesser mealworm beetle, Alphitobius diaperinus (Panzer), is a widespread serious pest in poultry production facilities and is difficult to control by conventional means.
Although pheromone-based tools have become useful in the management of other beetle pests, no pheromone was known for A. diaperinus, and this study sought to develop basic pheromone information. Volatiles were collected in the laboratory from groups of
male and female A. diaperinus maintained on poultry food (chick starter mash). Gas chromatographic–mass spectrometric analysis of volatiles collected from
feeding males and females revealed five male-specific compounds that were identified as (R)-(+)-limonene, (E)-β-ocimene, (S)-(+)-linalool, (R)-(+)-daucene, and 2-nonanone. Emission of these began 1–2 weeks after adult emergence and could continue for at least 1 year,
ceasing and resuming in response to changes in food availability and quality and other factors. No female-specific compounds
were discovered. A synthetic blend of the five male compounds was attractive to both sexes in poultry production facilities
in Illinois and Arkansas, indicating that the blend functions as an aggregation pheromone, but it is not yet known whether
all five compounds are required for activity. A new pitfall trap is described for field use. 相似文献
10.
W. M. N. Ratnayake C. Gagnon L. Dumais W. Lillycrop L. Wong M. Meleta P. Calway 《Journal of the American Oil Chemists' Society》2007,84(9):817-825
Dietary trans fatty acids (TFA) are of major concern because of their adverse effects on blood lipid levels and coronary heart disease.
In Canada, margarines were significant sources of TFA during the 1980s and 1990s. However, this is expected to change with
increased public awareness over their adverse health effects and the introduction of new legislature to include TFA content
on the Nutritional Facts table of food labels. In this study, the TFA content of the top-selling 29 Canadian margarines, which
represented 96.3% of the market share, was determined by capillary gas-liquid chromatography in order to assess the influence
of regulatory development during the 3-year transition period between the announcement of new food labelling regulations in
Canada that require mandatory declaration of the trans fat content in most pre-packaged foods in January 2003 and its enforcement on 12 December 2005. The 29 margarines included
15 tub margarines made from non-hydrogenated vegetable oils (NHVO-tub margarines), 11 tub margarines made from partially hydrogenated
vegetable oils (PHVO-tub margarines) and three print margarines, which were also made from partially hydrogenated vegetable
oils (PHVO-print margarines). The 15 NHVO tub-margarines accounted for 71% of the total margarine market share and generally
contained less than 2% TFA (mean value 0.9 ± 0.3% of total fatty acids). The mean total TFA contents of PHVO-tub margarines
and PHVO-print margarines, were 20.0 ± 4.5% and 39.6 ± 3.5%, and their market shares were 19.3 and 6.0%, respectively. Although
during the last 10 years, increasing number of soft tub margarines that contained very little trans fats have been made available in Canada, the PHVO-tub- and -print margarines still contain high levels of trans fats similar to those margarines that were sold in the 1990s. The market share data suggest that the margarines prepared
using NHVO and containing almost no TFA were preferred by Canadians over those margarines prepared using PHVO, even before
the mandatory declaration of TFA content came into effect on 12 December 2005. 相似文献
11.
Reaction selectivities were determined in multicompetitive reactions mediated by Rhizomucor miehei (RM) lipase at water activity of 0.19 in hexane. Saturated FA (C4–C18 even chain) and oleic acid (C18∶1) were reacted with
a single alcohol, glycerol, or α-or β-MAG containing C4, C10, C16, or C18∶1 individually as alcohol cosubstrate. Similar patterns
of broad FA selectivity toward C8–C18 FA were generally observed for esterification into specific acylglycerol (AG) pools
with the different α/β-CX-MAG cosubstrates. Exceptions were enrichment of C18 in the MAG pool with α-C16-MAG substrate, and
a general suppression of C4/C6 FA reactivity and a specific discrimination toward >C8 FA incorporation into the TAG pool,
both for reactions with α-C10- and α-C16-MAG. RM lipase selectivity toward MAG was in descending order: β-C18∶1-MAG>α/β-C4-MAG∼β-C10-MAG∼β-C16-MAG>α-C18∶1-MAG
>α-C10-MAG∼α-C16-MAG. Selectivity in channeling CX of the original CX-MAG substrates into higher AG species was in descending
order: α-C10-MAG∼α-C16-MAG>β-C10-MAGβ-C16-MAG>α-C18∶1-MAG>β-C18∶1-MAG∼ α/β-C4-MAG. Aside from their characteristic FA selectivity,
Burkholderia cepacia (PS-30) and RM lipases behaved similarly in terms of MAG selectivity as well as a general conservation of FA selectivity
throughout the sequential steps of TAG assembly from FA and glycerol for processes designed to yield specifically structured
TAG. 相似文献
12.
13.
Hong-Wei Wang In Hae Kim Chang-Su Park Jae-Hwa Lee 《Korean Journal of Chemical Engineering》2008,25(4):801-803
α-amylase from Bacillus licheniformis was successfully immobilized on developed support, which was prepared by coating a chitosan-casein film on silica, at 20
°C, pH 6.0 for 5 hr with microbial transglutaminase (MTG) as the cross-linking factor. The optimal support was obtained when
1% chitosan and 1% casein were used in the coating mixture. The optimal condition for immobilization catalyzed by MTG was
confined to be at MTG concentration of 15 U/mL, pH 6.0, reacting for 6 hr at 20 °C. The highest specific activity of immobilized
α-amylase was achieved as 236 U/g. After immobilization, the obtained enzyme showed broader pH profile and maintained more
than 70% of the original activity after 20 reuses. 相似文献
14.
John H. P. Tyman Robert A. Johnson 《Journal of the American Oil Chemists' Society》2007,84(6):573-578
To study the relationship between structure and properties of members of the lipidic thiobis phenol series, as extreme pressure
additives in lubricants, a series of homologous compounds has been synthesised by the reaction of alkylphenols with sulphur
dichloride. The isomeric n-nonylphenols have been reacted to form the C9 isomeric 2,2′-and 4,4′-thiobisphenols. Longer alkyl side-chains resulted mainly
in the formation of 4,4′-thiobisphenols and some of the 2,2′ isomer. With short alkyl, particularly t-alkyl side-chains, steric hindrance resulted in the 2,2′-compound. Additive studies have indicated that the longer chain
4,4′ compounds possessed antioxidant properties comparable and superior to former commercial branched chain 2,2′ compounds
produced from petrochemical intermediates.
Lipidic alkylthiobisphenols: Long chain phenols, Part 40b (Part 40a, ref 6). 相似文献
15.
Abdalbasit Adam Mariod Kawthar Mahmoud Aseel Ali Abdalgadir Mustafa Siddig Ibrahim Abdel-Wahab 《Journal of the American Oil Chemists' Society》2009,86(8):749-755
The oil and meal from Monechma ciliatum (black mahlab) and Prunus mahaleb (white mahlab) seeds were characterized for their physicochemical properties. The oil content was found to be 30.95 and 13.15%
in white and black mahlab seeds, respectively. The refractive indices of white mahlab oil (WMO) and black mahlab oil (BMO)
were 1.475 and 1.470, and specific gravities were 0.8511 and 0.8167 g/cm3, respectively. Saponification values were 184.23 and 180.3 mg KOH/g, peroxide values were 2.54 and 4.43 meq/kg, and unsaponifiable
matter was 0.92 and 0.66%, respectively. The major fatty acids were palmitic 4.5%, stearic 16.0%, oleic 47.3%, and linoleic
31.4% in BMO, while in WMO they were palmitic 5.7%, oleic 45.0%, and linoleic acid 47.0%. A moderate amount of tocopherols
were found at 45.2 and 28.5 mg/100 g in BMO and WMO, respectively. Protein content was found to be 21% in black and 28% in
white mahlab seeds. The total amount of amino acids in black and white mahlab seeds was found to be 783.3 and 1,223.2 mg/g N,
respectively. The concentration (on ppm dry-weight basis) of major elements (Ca, K, and Mg) and of minor elements (Al, Pb
Ni, Mn, Cu, Cr, Co, and Fe) was also determined in the meals. 相似文献
16.
17.
Male-Produced Aggregation Pheromone of the Cerambycid Beetle <Emphasis Type="Italic">Rosalia funebris</Emphasis> 总被引:2,自引:2,他引:0
Ann M. Ray Jocelyn G. Millar J. Steven McElfresh Ian P. Swift James D. Barbour Lawrence M. Hanks 《Journal of chemical ecology》2009,35(1):96-103
We report the identification, synthesis, and field bioassays of a volatile, male-produced aggregation pheromone of a long-horned
beetle, the banded alder borer, Rosalia funebris Mots. Headspace collections from males contained a major male-specific compound, (Z)-3-decenyl (E)-2-hexenoate, and several minor components, identified as (Z)-3-decenol, (Z)-3-nonenyl (E)-2-hexenoate, and (Z)-3-decenyl (E)-3-hexenoate. The antennae of both males and females responded strongly to (Z)-3-decenyl (E)-2-hexenoate. We collected significant numbers of adult R. funebris in field bioassays using traps baited with this compound. This pheromone structure is unprecedented in the literature of
cerambycid pheromones and distinct from the more common diol/hydroxyketone pheromone motif of many other species of the diverse
subfamily Cerambycinae. This is the first pheromone identified for a species in the tribe Rosaliini.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
18.
Aliou Faye Saidou Sall Jean-Luc Chotte Didier Lesueur 《Nutrient Cycling in Agroecosystems》2007,79(1):35-44
Acacia nilotica var. tomentosa trees from the Diarra protected forest located in the Senegal River valley were identified for the assessment of both biological
nitrogen fixation, using the natural abundance method, and soil bio-functioning parameters (nodulation, root biomass, total
microbial biomass, and potential N mineralization). The presence and the genetic diversity of indigenous rhizobia nodulating
A. nilotica var. tomentosa was also investigated, taking into account distance from the trunk (0, 1, 2, and 3 m) and depth (0–25, 25–50, and 50–75 cm).
Surprisingly, no nodules on the trees root systems were found, whereas under laboratory conditions the presence of indigenous
rhizobia nodulating A. nilotica var. tomentosa was demonstrated in the analyzed soils (90% of the nodules harvested on the trapped plants were occupied by the same Inter-Genic
Spacer (IGS) group, IGS1). There was no significant influence of trees and/or depth on total microbial biomass and potentials
of nitrogen mineralization. Some assumptions were formulated on the possible combined effect of flooding, which usually occurs
annually during 4–7 months, and the clayey soils in the Diara forests. Although a deeply natural nodulation of A. nilotica var. tomentosa trees by indigenous rhizobia is not excluded, but it still remains to be demonstrated. 相似文献
19.
Nikola Drenchev Tony Spassov Ivan Kanazirski 《Journal of Applied Electrochemistry》2008,38(2):197-202
The electrochemical hydriding/dehydriding under galvanostatic conditions of nanostructured Mg2-x
Sn
x
Ni (x = 0,0.1,0.3) were studied at different temperatures in the range 28–45 °C. The discharge capacity, cycle life and electrochemical
impedance of the alloys were found to depend on the presence of Sn. Tin decreases the maximum electrochemical capacity, but
essentially improves the cycle life of Mg2Ni. Intensive corrosion of surface Mg was found to take place during the first 2–3 charge/discharge cycles to a much larger
extent for Mg2Ni, compared to the tin containing alloys. Sn decreases the electron density around the Mg atoms and therefore impedes magnesium
oxidation. It was also found that Sn hampers charge transfer but reduces the hydrogen diffusion resistance in Mg2Ni based alloys. 相似文献
20.
A. A. Babaev I. K. Kamilov S. B. Sultanov A. M. Askhabov 《Glass Physics and Chemistry》2005,31(3):326-329
The optical absorption edge and the photoluminescence spectra of amorphous hydrogenated diamond-like carbon (a-C:H) films are investigated in the temperature range 4.2–900 K. Low-dimensional multilayer structures a-C:H/a-Si:H, in which a-C:H with an optical band gap E
g
= 4.5 eV is used as a barrier, are prepared for the first time. It is found that amorphous hydrogenated silicon (a-Si:H) films with a thickness d < 100 Å exhibit quantum-confinement effects. Analysis of the photoluminescence spectra and the optical absorption edge of the a-Si:H films shows that the structures a-C:H/a-Si:H have a sharp interface and that charge carriers in the a-Si:H film undergo quantization.Original Russian Text Copyright © 2005 by Fizika i Khimiya Stekla, Babaev, Kamilov, Sultanov, Askhabov. 相似文献