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1.
The principal molecular species of sphingolipids in wheat grain were confirmed to beN-2′-hydroxylignoceroyl-4-hydroxysphinganine for ceramide, and 1-O-β-glucosyl-, 1-O-[β-mannosyl(1→4)-O-β-glucosyl]-, 1-O-[β-mannosyl(1→4)-O-β-mannosyl(1→4)-O-β-glucosyl]-and 1-O[β-mannosyl(1→4)-O-β-mannosyl(1→4)-O-β-mannosyl(1→4)-O-β-glucosyl]-N-2′-hydroxypalmitoyl (or hydroxyarachidoyl)-cis-8-sphingenine for mono-, di-, tri- and tetraglycosylceramide, respectively. A novel glycolipid, cellobiosylceramide, was
found as the minor diglycosylceramide; the major species was characterized to be 1-O-[β-glucosyl(1→4)-O-β-glucosyl]-N-2′-hydroxypalmitoyl (or hydroxyarachidoyl)-cis-8-sphingenine. It was observed in these sphingolipids that the dihydroxy bases were combined mainly with C16 and C20 acids, whereas the trihydroxy bases combined mostly with acids of chain length of 20 or more. 相似文献
2.
New glyceroglycolipid and ceramide from <Emphasis Type="Italic">Premna microphylla</Emphasis> 总被引:1,自引:0,他引:1
Iwo new compounds (1,2) were isolated from the ethanolic extract of the leaves of Premna microphylla, together with five known compounds. The structures of compounds 1 and 2 were elucidated as (2S,3S,4R,11E)-2-[(2R)-2-hydroxytetracosanoylamino]-11-octadecene-1,3,4-triol (1) and 1-O(9Z,12Z, 15Z-octadecatrienoyl)-3-O-[β-d-galactopyranosyl-(1→6)-O-β-d-galactopyranosyl-(1→6)-α-d-galactopyranosyl] glycerol (2) by means of spectroscopic and chemical methods. 相似文献
3.
Acylated glycoglycerolipids were identified in the total lipid extract from cyanobacerium Synechocystis sp. PCC 6803. These compounds have a palmitoyl group esterified to the hydroxyl group at the C-6 position of the terminal
glycosyl moiety of digalactosyl monoacylglycerol and digalactosyl diacylglycerol. Their structural elucidation was accomplished
by tandem mass spectrometry coupled with fast atom bombardment ionization. Acylated digalactosyl monoacylglycerol has a structure
of 1-hydroxy-2-palmitoyl-3-O-[(6-O-palmitoyl)-α-d-galactopyranosyl-(1→6)-β-d-galactopyranosyl]-sn-glycerol. This compound has not been reported previously. 相似文献
4.
The net rates of uptake of “new” and loss of “old”2R,4′ R,8′ R-α-tocopherol (RRR-α-TOH, which is natural vitamin E) have been measured in the blood and in nine tissues of male guinea pigs over an eight
week period by feeding diets containing deuterium-labelled α-tocopheryl acetate (d
6-RRR-α-TOAc). There was an initial two week “lead-in” period during which 24 animals [the “high” vitamin E (HE) group] received
diets containing 36 mg of unlabelled (d
0)RRR-α-TOAc and 250 mg of ascorbic acid per kg diet, while another 24 animals [the “low” vitamin E (LE) group] received diets
containing 5 mgd
0-RRR-α-TOAc and 250 mg ascorbic acid per kg diet. The HE group was then tivided into three equal subgroups, which were fed diets
containing 36 mgd
6-RRR-α-TOAc and 5000 mg [the “high” vitamin C (HEHC) subgroup], 250 mg [the “normal” vitamin C (HENC) subgroup] and 50 mg [the
“low” vitamin C (HELC) subgroup] ascorbic acid per kg diet. One animal from each group was sacrificed each week and the blood
and tissues were analyzed ford
0- andd
6-RRR-α-TOH by gas chromatography-mass spectrometry. The LE group was similarly divided into three equal subgroups with animals
receiving diets containing 5 mgd
6-RRR-α-TOAc and 5,000 mg (LEHC), 250 mg (LENC) and 50 mg (LELC) ascorbic acid per kg diet with a similar protocol being followed
for sacrifice and analyses. In the HE group the totald
0-+d
6-)RRR-α-TOH concentrations in blood and tissues remained essentially constant over the eight week experiment, whereas in the LE
group the totalRRR-α-TOH concentrations declined noticeably (except in the brain, an organ with a particularly slow turnover of vitamin E).
There were no significant differences in the concentrations of “old”d
0-RRR-α-TOH nor in the concentrations of “new”d
6-RRR-α-TOH found in any tissue at a particular time between the HEHC, HENC and HELC subgroups, nor between the LEHC, LENC and
LELC subgroups. We conclude that the long-postulated “spring” action of vitamin C on vitamin E, which is well documentedin vitro, is of negligible importancein vivo in guinea pigs that are not oxidatively stressed in comparison with the normal metabolic processes which consume vitamin
E (e.g., by oxidizing it irreversibly) or elminate it from the body. This is true both for guinea pigs with an adequate, well-maintained
vitamin E status and for guinea pigs which are receiving insufficient vitamin E to maintain their body stores.
The biokinetics of vitamin E uptake and loss in the HE guinea pigs are compared with analogous data for rats reported previously
(Lipids 22, 163–172, 1987). For most guinea pig tissues the uptake of vitamin E under “steadystate” conditions was faster than for the
comparable rat tissues. However, the brain was an exception with the turnover of vitamin E occurring at only one-third of
the rate for the rat.
NRCC Publication No. 30775. 相似文献
5.
The acceptance of Solanum surattenses as a host plant for the larvae of Manduca sexta was explained by the presence of feeding stimulants in foliage. Bioassay-guided fractionation of plant extracts resulted in the isolation of a highly active compound (1), which was identified as a furostan derivative {26-O-β-d-glucopyranosyl-(25R)-furosta-5-ene-3-β-yl-O-α-l-rhamnopyranosyl-(1″-2′)-O-α-l-rhamnopyranosyl-(1′″-3″)-O-β-d-glucopyranoside}. This compound has the same steroidal core substructure as that in a stimulant (indioside D) previously identified from potato foliage. However, the sugar substituents attached to the core are different. 相似文献
6.
Recently, we have reported that anthocyanins show strong antioxidative activity, but no attention has been paid to anthocyanins
from the viewpoint of the reaction mechanism of alkylperoxyl radicals; therefore, we investigated the reaction products of
antioxidative anthocyanins (cyanidin 3-O-β-d-glucoside). Cyanidin 3-O-β-d-glucoside was reacted with 2,2′-azobis(2,4-dimet hylvaleronitrile) to generate the alkylperoxyl radicals, and the reaction
products were isolated by high-performance liquid chromatography. The products were identified as 4,6-dihydroxy-2-O-β-d-glucosyl-3-oxo-2,3-dihydrobenzofuran and protocatechuic acid. Based on reaction products, the antioxidative mechanism of
cyanidin 3-O-β-d-glucoside may be different from that of α-tocopherol; cyanidin 3-O-β-d-glucoside would produce another radical scavenger, as it would break down the structure and scavenge the radicals. 相似文献
7.
Novel ceramides and a new glucoceramide from the roots of <Emphasis Type="Italic">Incarvillea arguta</Emphasis> 总被引:3,自引:0,他引:3
Novel ceramides, rel-(3S,4S,5S)-3-[(2R)-2-hydroxycosanoyl-hexacosanoylamino]-4-hydroxy-5-[(4Z)-tetradecane-4-ene]-2,3,4,5-tetrahydrofuran (1a-g), and a new glucoceramide, 1-O-β-d-glucopyranosyl-(2S,3S,4R,8E)-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octodecanetriol-8-ene (2) were isolated from the aqueous ethanolic extract of the roots of Incarvillea arguta, together with eight known compounds: β-sitosterol (3), oleanolic acid (4), ursolic acid (5), piperin (6), maslinic acid (7), β-sitosterol 6′-O-acyl-β-d-glucopyranoside (8), 8-epideoxyloganic acid (9), and plantarenaloside (10). Their structures were elucidated on the basis of spectral data including IR, MS, NMR [1H NMR, 13C NMR (distortionless enhancement by polarization transfer), 1H−1H COSY, heteronuclear multiplequantum coherence, and heteronuclear multiple-bond coherence correlations]. The relative configurations
were established by nuclear Overhauser effect spectroscopy experiments and by comparison of the NMR spectral data and coupling
constants with those already reported in the literature. 相似文献
8.
Five cerebrosides (1–5), including three new ones named cortenuamide A (1), cortenuamide B (2), and cortenuamide C (3), were isolated from the fruiting bodies of the basid-iomycete Cortinarius tenuipes. The structures of those compounds were elucidated as (4E,8E)-N-d-2′-hydroxytetracosanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (1), (4E,8E)-N-d-2′-hydroxytricosanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8 sphingadienine (2), (4E, 8E)-N-d-2′-hydroxydocosanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (3), (4E, 8E)-N-d-2′-hydroxyoctadecanoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (4), and (4E, 8E)-N-d-2′-hydroxypalmitoyl-1-O-β-d-glycopyranosyl-9-methyl-4,8-sphingadienine (5) by spectral and chemical methods. 相似文献
9.
Ramesh N. Patel Ronald L. Hanson Amit Banerjee Laszlo J. Szarka 《Journal of the American Oil Chemists' Society》1997,74(11):1345-1360
Chiral intermediates were prepared by biocatalytic processes with oxidoreductases for the chemical synthesis of some pharmaceutical
drug candidates. These include: (i) the microbial reduction of 1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1-piperazinyl]-1-butanone
(1) to R-(+)-1-(4-fluorophenyl)-4-[4-(5-fluoro-2-pyrimidinyl)-1-piperazinyl]-1-butanol (2) [R-(+)-BMY 14802], an antipsychotic agent; (ii) the reduction of N-4-(1-oxo-2-chloroacetyl ethyl) phenyl methane sulfonamide (3) to the corresponding chiral alcohol (4), an intermediate for d-(+)-N-4-{1-hydroxy-2-[(-methylethyl)amino]ethyl}phenyl methanesulfonamide [d-(+) sotalol], a β-blocker with class III antiarrhythmic properties; (iii) biotransformation of Nɛ-carbobenzoxy (CBZ)-l-lysine (7) to Nɛ-CBZ-l-oxylysine (5), an intermediate needed for synthesis of (S)-1-[6-amino-2-{[hydroxy(4-phenylbutyl)phosphinyl]oxy}1-oxohexyl]-l-proline (ceronapril), a new angiotensin converting enzyme inhibitor (6) and (iv) enzymatic synthesis of l-β-hydroxyvaline (9) from α-keto-β-hydroxyisovalerate (16). l-β-Hydroxyvaline (9) is a key chiral intermediate needed for the synthesis of S-(Z)-{[1-(2-amino-4-thiazolyl)-2-{[2,2-dimethyl-4-oxo-1-(sulfooxy)-3-azetidinyl] amino}-2-oxoethylidene]amino}oxyacetic acid
(tigemonam) (10), an orally active monobactam. 相似文献
10.
Maret G. Traber Shreekumar R. Pillai Herbert J. Kayden Janet E. Steiss 《Lipids》1993,28(12):1107-1112
The plasma and lipoprotein transport ofRRR andall rac-α-tocopherols, labeled with different amounts of deuterium [2R,4′R,8′R-α-[5-C2H3]tocopheryl acetate (d
3
RRR-α-tocopheryl acetate] and 2RS, 4′RS, 8′RS-α-[5,7-(C2H3)2]tocopheryl acetate (d
5
all rac-α-tocopheryl acetate), was studied in adult beagle dogs that had been fed a vitamin E-deficient (−E; two dogs) or supplemented
(+E; two dogs) diet for two years. We set out to test the hypothesis that the activity of the hepatic tocopherol binding protein
(which is thought to preferentially incorporateRRR-α-tocopherol into the plasma) is up-regulated by vitamin E deficiency. Labeled α-tocopherols increased and decreased similarly
in plasma of both −E and +E dogs. Irrespective of diet,d
3
RRR-α-tocopherol was preferentially secreted in plasma. Thus, vitamin E deficiency in dogs does not markedly increase the apparent
function of the hepatic tocopherol binding protein. We also studied vitamin E transport in a German Shepherd dog with degenerative
myelopathy (DM). Based on the coincident appearance ofd
3
RRR-α-tocopherol in plasma and chylomicrons, we suggest that the abnormality in DM may be associated with abnormal vitamin E
transport resulting from an impaired function of the hepatic tocopherol binding protein. 相似文献
11.
Livy WilliamsIII Jacquelyn L. Blackmer Cesar Rodriguez-Saona Su Zhu 《Journal of chemical ecology》2010,36(5):467-478
Previous laboratory studies have shown that the mirid Lygus hesperus is attracted to volatiles emitted from alfalfa; feeding damage increases the amounts of several of these volatiles, and visual
cues can enhance attraction further. The present study tested single plant volatiles in electrophysiological and behavioral
trials with L. hesperus. Electroantennogram (EAG) analyses indicated that antennae responded to most plant volatiles included in the test, and that
when gender differences were observed, males usually were more responsive than females. Antennal responses to the alcohols
((E)-3-hexenol, (Z)-3-hexenol, 1-hexanol), the acetate (E)-2-hexenyl acetate, and the aldehyde (E)-2-hexenal were among the strongest. Moderate responses were observed for (E)-β-ocimene, (E,E)-α-farnesene, (±)-linalool, and methyl salicylate. A dose dependent response was not observed for several terpenes (β-myrcene,
β-caryophyllene, (+)-limonene, or both (R)-(+)- and (S)-(−)-α-pinenes). EAG responses, however, were not always consistent with behavioral assays. In Y-tube bioassays, males did
not exhibit a positive behavioral response to any of the compounds tested. Instead, males were repelled by (E)-2-hexenyl acetate, (±)-linalool, (E,E)-α-farnesene, and methyl salicylate. In contrast, female L. hesperus moved upwind towards (R)-(+)-α-pinene, (E)-β-ocimene, and (E,E)-α-farnesene, and showed a negative response towards (Z)-3-hexen-1-ol, (S)-(−)-α-pinene, and methyl salicylate. This study emphasizes the use of multiple approaches to better understand host plant
finding in the generalist herbivore L. hesperus. 相似文献
12.
Two new monogalactosyl diacylglycerols (MGDGs) along with two known glycolipids were isolated from the moderate polar fraction
of the methanolic extract of the brown alga Sargassum thunbergii by using reversed silica flash chromatography. Two new MGDGs were identified as (2S)-1-O-(5Z,8Z,11Z,14Z,17Z-eicosapentaenoyl)-2-O-(9Z,12Z,15Z-octadecatrienoyl)-3-O-β-d-galactopyranosyl-sn-glycerol (1) and (2S)-1-O-(9Z,12Z,15Z-octadecatrienoyl)-2-O-(6Z,9Z,12Z,15Z-octadecatetraenoyl)-3-O-β-d-galactopyranosyl-sn-glycerol (2) by FAB tandem mass spectrometry, NMR techniques, and specific enzyme-catalyzed hydrolysis of the sn-1 fatty acyl linkage. The regiochemical attachment of the acyl chains in the glycerol moiety was established by 2D NMR correlations
and confirmed by enzymatic hydrolysis. 相似文献
13.
Chung Il Hong Charles R. West Ralph J. Bernacki Cameron K. Tebbi Wolfgang E. Berdel 《Lipids》1991,26(12):1437-1444
The 1-β-D-arabinofuranosylcytosine (ara-C) conjugates 1-O-alkyl (ether) and 1-S-alkyl (thioether) phospholipids, being analogues of ara-CDP-sn-1,2-O-dipalmitoylglycerol (1), showed significant antitumor activity against L1210 and P388 leukemiain vivo. The more active conjugates include the 1-O-alkyl analogues, ara-CDP-rac-1-O-hexadecyl-2-O-palmitoylglycerol (2) and ara-CDP-rac-1-O-octadecyl-2-O-palmitoylglycerol (3), and the corresponding 1-S-alkyl analogues, ara-CDP-rac-1-S-hexadecyl-2-O-palmitoyl-1-thioglycerol (4) and ara-CDP-rac-1-S-octadecyl-2-O-palmitoyl-1-thioglycerol (5, Cytoros). The conjugates were formulated by sonication, in which the conjugates existed as discs
(size 0.01–0.04 μ).. Among the conjugates of the three different phospholipids, the 1-S-alkyl analogues 4 and 5 displayed the strongest antitumor activity against L1210 leukemia in mice, followed by the 1-O-alkyl (2 and 3) and the 1-O-acyl (1) analogues. The 1-S-alkyl analogue 5 was considerably more effective than the 1-O-acyl analogue 1 against myelomonocytic WEHI-3B leukemia in mice. Conjugate 5 (Cytoros) showed a significant therapeutic activity
in mice with colon 26 carcinoma, M5076 sarcoma, and C-1300 neuroblastoma. Furthermore, this agent inhibited liver metastases
of M5076 sarcoma. Conjugates 3 and 5 also inhibited the metastasis of 3-Lewis lung carcinoma to the lungs of mice. Cytoros
(5) and its analogues, with other ether and thioether phospholipids, appear to offer increased therapeutic benefit to mice
with tumors.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
14.
A new diacylgalactolipid was isolated from the marine cyanobacterium Oscillatoria sp., and the structure was elucidated as (2S)-3-O-β-d-galactopyranosyl-1-O-(9Z,12Z-octadecadienoyl)-2-O-(4Z-hexadecenoyl)glycerol by enzymatic partial hydrolysis using lipase and physicochemical evidence, which included determining
the double bond position in the hexadecenoic acid moiety. 相似文献
15.
A new glucoceramide from the watermelon begonia, <Emphasis Type="Italic">Pellionia repens</Emphasis> 总被引:1,自引:0,他引:1
A new glucoceramide named pellioniareside (1) was isolated from the aqueous ethanolic extract of whole plants of Pellionia repens, together with lupeol (2), uracil (3), (22E,20S,24R)-5α,8α-epidioxyergosta-6,22-dien-3-β-ol (4), and daucosterol (5). The structure and relative configurations of pellioniareside were identified as (2S,3S,4R,6E,8E)-1-O-β-d-glucopyranosyl-2-[(2R)-2-hydroxytetracosanoylamino]-1,3,4-octadecanetriol-6,8-diene by analysis of spectral data and by chemical evidence. 相似文献
16.
Toshikazu Sakaguchi Ken-ichi Yumoto Giseop Kwak Masakazu Yoshikawa Toshio Masuda 《Polymer Bulletin》2002,48(3):271-276
Summary
In the ethanol/water pervaporation using membranes of Si-containing polymers, poly[1-phenyl-2-(p-trimethylsilyl)phenylacetylene] and poly[1-β-naphthyl-2-(p-trimethylsilyl)phenylacetylene], these polymer membranes permeated ethanol preferentially; αEtOH/H2O 6.86 and 5.30, respectively, at 10 wt% EtOH content in the feed. Membranes of hydrocarbon-based polymers, poly(diphenylacetylene)
and poly(1-β-naphthyl-2-phenylacetylene), which were prepared by desilylation of the two Si-containing polymer membranes,
also exhibited ethanol permselectivity in ethanol/water pervaporation; αEtOH/H2O 5.95 and 3.79, respectively. Further, in benzene/cyclohexane pervaporation, these desilylated membranes, which were insoluble
in any organic solvent, showed rather low benzene permselectivity but very large fluxes. The results of the present study
are attributed to the presence of many microvoids and, in turn, sparse structures.
Received: 6 March 2002/ Accepted: 28 March 2002 相似文献
17.
We established a method to simultaneously determine RRR- and SRR-α-tocopherol (α-Toc) and their quinones in biological samples by chiral-phase high-performance liquid chromatography (HPLC).
α-Toc had a shorter retention time than α-tocopherylquinones (α-TQ), and 2-ambo-α-Toc was completely separated into two peaks; the first peak was RRR-α-Toc and the second SRR-isomer by chiral HPLC connected Chiralcel OD-H column and Sumichiral OA4100 column. In contrast, of the two peaks of α-TQ,
the first was the SRR-isomer. We also investigated differences in the distribution of RRR- and SRR-α-TQ in rat tissues after oral administration of 2-ambo-α-Toc by the above HPLC method. Rats deficient in vitamin E were divided into two groups, control and experimental, and tissues
were collected at 3, 6, and 24 h after oral 2-ambo-α-Toc administration. The concentrations of RRR- and SRR-α-Toc and their quinones in plasma and each tissue were determined. The concentration of SRR-α-TQ in plasma and adrenal glands was not significantly different from RRR-α-TQ. However, the concentration of SRR-α-TQ in liver up to 6 h after oral administration was higher than that of RRR-α-TQ, and SRR- and RRR-α-TQ levels were similar at 24 h after oral administration. Therefore, we may assume that the formation of α-TQ in vivo was not different between RRR- and SRR-isomer and that it was not affected by the presence of α-Toc stereoisomers. 相似文献
18.
M. Judith Percino Víctor M. Chapela Alicia Camacho Guillermo Soriano-Moro Margarita Cerón 《Journal of Polymer Research》2011,18(4):559-568
The kinetics of atom transfer radical polymerization of N-(S)-α-methylbenzylmethacryloylamine (S-(-)-α-MBMA) and α-methylbenzylmethacrylate
(α-MBM) monomers, as assessed by % conversion, were determined at 48 °C in a toluene/ethanol mixture (60:40) by a dilatometry
method. The effect of the presence of — CONH- or — COOR- moieties on the ATRP polymerization of such monomers was investigated.
Controlled polymerizations were performed with the catalyst system [ M ]/[ R - X ]/[ Mtn - Y ]/[ L ] \left[ {\hbox{M}} \right]/\left[ {{\hbox{R}} - {\hbox{X}}} \right]/\left[ {{\hbox{M}}{{\hbox{t}}^{\rm{n}}} - {\hbox{Y}}} \right]/\left[ {\hbox{L}} \right] at molar ratios of 100:15:15:15; 200:15:15:15; 300:15:15:15; and 400:15:15:15, where R-X was EBIB or MCP, Mtn-Y(CuBr or CuCl) and L (Me6TREN). Also with N-S-(-)-α-MBMA, some studies used ATCA and ABPA as R-X. Plots of the ln[M]0/[M] vs t as well as from the log Rp vs log [M] showed that the ATRP processes followed a pseudo first-order kinetics with respect to the monomer concentration and
that the molecular weight of the resulting polymers increased with the conversion. The ATRP results for both monomers showed
a similar trend and revealed that the presence of N-S-(-)-α-MBMA (amide group) affects the polymerization, i.e. it did not
react when the EBIB/CuBr/Me6TREN catalyst system was used. The Mn and Mw were determined by 1H-NMR and GPC. PDI values fell between 1.19 and 1.5, and indicated that the majority of the systems showed good control of
polymerization. 相似文献
19.
Sequestration of Furostanol Saponins by <Emphasis Type="Italic">Monophadnus</Emphasis> Sawfly Larvae
Prieto JM Schaffner U Barker A Braca A Siciliano T Boevé JL 《Journal of chemical ecology》2007,33(3):513-524
Sawfly larvae of the tribe Phymatocerini (Hymenoptera: Tenthredinidae), which are specialized on toxic plants in the orders
Liliales and Ranunculales, exude a droplet of deterrent hemolymph upon attack by a predator. We investigated whether secondary
plant metabolites from Ranunculaceae leaves are sequestered by phymatocerine Monophadnus species, i.e., Monophadnus alpicola feeding upon Pulsatilla alpina and Monophadnus monticola feeding upon Ranunculus lanuginosus. Moreover, two undescribed Monophadnus species were studied: species A collected from Helleborus foetidus and species B collected from Helleborus viridis. Comparative high-performance liquid chromatographic–photodiode array detection–electrospray ionization–mass spectrometric
analyses of plant leaf and insect hemolymph extracts revealed the presence of furostanol saponins in all samples. Larvae of
species A and B actively sequestered (25R)-26-[(α-l-rhamnopyranosyl)oxy]-22α-methoxyfurost-5-en-3β-yl O-β-d-glucopyranosyl-(1→3)-O-[6-acetyl-β-d-glucopyranosyl-(1→3)]-O-β-d-glucopyranoside (compound 1). This compound occurred at a 65- to 200-fold higher concentration in the hemolymph of the two species (1.6 and 17.5 μmol/g
FW, respectively) than in their host plant (0.008 and 0.268 μmol/g FW, respectively). In M. monticola, compound 1 was found at a concentration (1.2 μmol/g FW) similar to that in the host plant (1.36 μmol/g FW). The compound could not be
detected consistently in M. alpicola larvae where, however, a related saponin may be present. Additional furostanol saponins were found in H. foetidus and H. viridis, but not in the two Monophadnus species feeding on them, indicating that sequestration of compound 1 is a highly specific process. In laboratory bioassays, crude hemolymph of three Monophadnus species showed a significant feeding deterrent activity against a potential predator, Myrmica rubra ant workers. Isolated furostanol saponins were also active against the ants, at a concentration range similar to that found
in the hemolymph. Thus, these compounds seem to play a major role for chemical defense of Monophadnus larvae, although other plant secondary metabolites (glycosylated ecdysteroids) were also detected in their hemolymph. Physiological
and ecological implications of the sequestered furostanol saponins are discussed.
Dedicated to the memory of Professor Ivano Morelli (1940–2005) 相似文献
20.
The existence of ether-linked phospholipids, including 1-O-alk-1′-enyl-2-acyl and 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholines and ethanolamines in bonitoEuthynnus pelamis (Linnaeus) white muscle, was investigated by gas chromatography and gas chromatography-mass spectrometry. Chemical ionization
(iso-butane) mass spectrometry of trimethylsilyl ethers derived from the corresponding ether-linked glycerophospholipids proved
effective not only for determining molecular weights but also for structural identification based on the ions [M−R]+, [M−RO]+ and [M+1]+. 1-O-Alk-1′-enyl-2-acyl-sn-glycero-3-phosphocholine and ethanolamine accounted for 3.0–6.0% and 3.6–7.6% of the total glycerophospholipids, respectively.
1-O-Alkyl-2-acyl-sn-glycero-3-phosphocholine and ethanolamine were also determined for one fish and accounted for 1.4% and 0.6% of the total
glycerophospholipids, respectively. The predominant long chains in thesn-1 position of the glycerol moieties were 16∶0, 18∶0 and 18∶1 in the case of the alkenylacyl and alkylacyl components. Fatty
acid distribution of individual glycerophospholipids was also determined. 相似文献