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1.
Clarkia breweri (Onagraceae) is the only species known in its genus to produce strong floral fragrance and to be pollinated by moths. We used gas chromatography-mass spectrometry (GC-MS) to identify 12 abundant compounds in the floral headspace from two inbred lines ofC. breweri. These volatiles are derived from two biochemical pathways, one producing acyclic monoterpenes and their oxides, the other leading from phenylalanine to benzoate and its derivatives. Linalool and linalool oxide (pyran form) were the most abundant monoterpenoids, while linalool oxide (furan form) was present at lower concentrations. Of the aromatic compounds detected, benzyl acetate was most abundant, whereas benzyl benzoate, eugenol, methyl salicylate, and vanillin were present as minor constituents in all floral samples. The two inbredC. breweri lines differed for the presence of the additional benzenoid compounds isoeugenol, methyleugenol, methylisoeugenol, and veratraldehyde. We also analyzed floral headspace fromC. concinna, the likely progenitor ofC. breweri, whose flowers are odorless to the human nose. Ten volatiles (mostly terpenoids) were detected at low concentrations, but only when headspace was collected from 20 or more flowers at a time. Trans--ocimene was the most abundant floral compound identified from this species. Our data are consistent with the hypothesized recent evolution of floral scent production and moth pollination inC. breweri. 相似文献
2.
Magorzata Kiekiewicz Ewa Puchalska Barbara Czajkowska 《Acta Physiologiae Plantarum》2005,27(4):463-472
The impact of spruce spider mite (SSM) (Oligonychus ununguis Jacobi, Acari: Tetranychidae) feeding on needle compounds of young dwarf white spruce (Picea glauca ‘Conica’), important in defence against pests, was determined. It was shown that the direction and intensity of changes in
chemical composition of spruce needles was related to the density of spruce spider mite population. Relative to uninfested
controls, needles of trees infested by 2–6 mites per 5 cm oftwig during 8 weeks contained markedly higher concentration of
soluble proteins, total phenolics and essential oil volatiles (linalool, β-phellandrene, β-myrcene, δ-3-carene, p-cymene, limonene, α-pinene, β-pinene, borneol, methyl salicylate, geranyl acetate). Feeding of a three times larger population
of mites (18 specimens per 5 cm of twig) caused either reduction of concentration of those compounds, or no significant difference
in comparison to the control.
The results of our study show that O. ununguis at relatively low density (not exceeding 2–6 specimens per 5 cm of twig per 8 weeks) stimulates even susceptible host-plant
to alter metabolism, however induced responses are suppressed as mite density increases. Findings are discussed in relation
to the importance of changes in the concentration of needle primary and secondary metabolites to white spruce defence against
O. ununguis. 相似文献
3.
The effect of needle damage on the release rate of Masson pine (Pinus massoniana Lamb.) volatiles was examined. Needles were continuously damaged by mechanical damage (MDP) or by feeding of pine caterpillar
(Dendrolimus punctatus) larvae (LFP); undamaged pine was used as a control (UDP). Volatiles were collected before damage, and at 16, 24, 40, 48,
64, 72, 88 and 96 h post-damage, and analyzed. The analyses revealed that 19 compounds identified as constitutive volatiles
from UDP were terpenes and green leaf odors. The release rate of volatiles from MDP or LFP was higher than that from UDP.
At 96 h post-damage, emission from MDP or LFP returned to the same level as that of UDP. Some volatiles, including sabinene,
ocimene, limonene-1,2-epoxide, linalool, linalool acetate, germacrene d-4-ol, farnesol, and (E)-4,8-dimethyl-1,3,7-nonatriene were induced by mechanical damage and/or larval attack. Furthermore, the release rate of linalool
acetate, farnesol, or (E)-4,8-dimethyl-1,3,7-nonatriene from LFP was higher than that from MDP. Based on an exact estimation of the proportion of
damaged pine needles, a significant linear correlation between the release rate of total volatiles identified and the proportion
of damaged needles was found in the case of LFP but not MDP. 相似文献
4.
Rhythmic emission of floral volatiles from<Emphasis Type="Italic"> Rosa damascena semperflorens</Emphasis> cv. ‘Quatre Saisons’ 总被引:1,自引:0,他引:1
The control of rhythmic emission of floral volatiles emitted from Rosa damascena semperflorens cv. Quatre Saisons throughout floral development under various light regimes was studied. 2-Phenylethanol was the major volatile emitted in addition to monoterpenols, oxidised monoterpenols, monoterpenes and aromatic compounds. All detected volatiles were emitted rhythmically, with maximum peaks coinciding 8–10 h into a 12-h photoperiod. For some compounds a secondary, nocturnal peak was apparent. The primary and secondary maxima both occurred at approximately 24-h intervals. Rhythms appeared to be regulated endogenously: rhythmic emission continued upon exposure to continuous light or continuous darkness, and a phase shift in emission was induced upon inversion of the photoperiod. Additionally, emission continued after flower excision. A similar profile of free volatiles was stored within the floral tissue, together with glycosidic forms of 2-phenylethanol (>99% -d-glucoside), benzyl alcohol, citronellol and geraniol. Regression analysis indicated a significant decrease in glycosylated 2-phenylethanol through the photoperiod. These results suggest that glycosylated volatiles stored within petals may be a source of rhythmically emitted volatiles.Abbreviations CD Continuous darkness - CL Continuous light - 2-PE 2-Phenylethanol - 2-PEG 2-Phenylethyl -d-glucopyranoside 相似文献
5.
Electroantennogram (EAG) responses were recorded from apterous virginoparae of the vetch aphidMegoura viciae Buckton (Homoptera, Aphididae) to more than eighty volatile compounds in order to investigate its sensory ability to perceive
plant odours. The response profile ofM. viciae reveals a differential sensitivity for the array of plant volatiles tested. The whole group of general green leaf volatiles
is very stimulatory. In addition to (E)-2-hexenal, the following compounds of this group elicit large EAG responses: (E)-2-heptenal, 1-octenol-3, hexyl acetate, (Z)-3-hexenyl acetate, hexanol-1, hexanal, 2-heptanone and 3-octanone. Relatively large EAGs are also produced by 4-methoxybenzaldehyde
(p-anisaldehyde), hexanonitrile, heptanonitrile, 1,6-hexanedithiol, butyl isothiocyanate, 4-pentenyl isothiocyanate, (−)-(1S)-β-pinene, (+)-(S)-carvone, (−)-(R)-carvone, α-terpineol, linalool and citronellal. The nitriles are the most effective of all plant volatiles tested. Structure-activity
relationships occur in various groups of chemicals and members of the green leaf volatiles, benzaldehydes, isothiocyanates
and monoterpenes are ranked accordingly. In the group of green leaf volatiles, aliphatic aldehydes are more stimulating than
the corresponding alcohols. EAG responses to series of saturated aliphatic alcohols and aldehydes reveal that C6 and C7 compounds are the most stimulatory. Dose-response curves show that the rank order of EAG response amplitudes hardly changes
at lower dosages. It is concluded thatM. viciae perceives general plant volatiles as well as more-specific components, such as nitriles and isothiocyanates, associated with
the odour blends of non-host plant species. 相似文献
6.
QTL mapping of aroma compounds analysed by headspace solid-phase microextraction gas chromatography in the apple progeny ‘Discovery’ × ‘Prima’ 总被引:2,自引:0,他引:2
F. Dunemann D. Ulrich A. Boudichevskaia C. Grafe W. E. Weber 《Molecular breeding : new strategies in plant improvement》2009,23(3):501-521
Improving fruit quality of apple varieties is an important but complex breeding goal. Flavour is among the key factors of
apple fruit quality but in spite of the analytical and biochemical knowledge about volatiles little is known about the genetic
and molecular bases of apple aroma. The aim of this study was to use a saturated molecular linkage map of apple to identify
QTLs for aroma compounds such as alcohols, esters and terpenes, but also for a number of unidentified volatile compounds (non-targeted
analysis approach). Two parental genetic maps were constructed for the apple cultivars ‘Discovery’ and ‘Prima’ by using mainly
AFLP and SSR markers. ‘Discovery’ and ‘Prima’ showed very different volatile patterns, and ‘Discovery’ mostly had the higher
volatile concentrations in comparison with the Vf-scab resistant ‘Prima’ which has its origin in the small-fruited apple species Malus floribunda. About 50 putative QTLs for a total of 27 different apple fruit volatiles were detected through interval mapping by using
genotypic data of 150 F1 individuals of the mapping population ‘C3’ together with phenotypic data obtained by head-space solid phase microextraction
gas chromatography. QTLs for volatile compounds putatively involved in apple aroma were found on 12 out of the 17 apple chromosomes,
but they were not evenly dispersed. QTLs were mainly clustered on linkage groups LG 2, 3 and 9. In a first attempt, a LOX
(lipoxygenase) candidate gene, putatively involved in volatile metabolism, was mapped on LG 9, genetically associated with
a cluster of QTLs for ester-type volatiles. Implications for aroma breeding in apple are discussed. 相似文献
7.
Volatiles released from cotton plants in response to<Emphasis Type="Italic"> Helicoverpa zea</Emphasis> feeding damage on cotton flower buds 总被引:7,自引:0,他引:7
Feeding of Helicoverpa zea larvae on cotton (Gossypium hirsutum L.) flower buds (squares) for 24 or 48 h induced the release of a number of terpenes [(E)--ocimene, linalool, (E)--farnesene, (E,E)--farnesene, (E)-4,8-dimethyl-1,3,7-nonatriene, (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene], isomeric hexenyl butyrates, 2-methylbutyrates, indole and (Z)-3-hexenyl acetate. These compounds are not released in significant amounts from undamaged squares and freshly damaged squares. The release of inducible compounds was not limited to the damaged squares themselves. The compounds were also released systemically from the upper undamaged leaves of the same plant after 72 h. However, the composition of the blend of systemically released volatiles differed from the blend released by damaged squares. The compounds that were systemically released from undamaged leaves in response to feeding on the squares were (Z)-3-hexenyl acetate, (E)--ocimene, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, (E)--farnesene, (E,E)--farnesene, and indole. This study shows that insect damage inflicted to the reproductive parts of a plant causes a systemic emission of volatiles from its vegetative parts. 相似文献
8.
Ginsenoside Rb1 is the most predominant ginsenoside in Panax species (ginseng) and the hydrolysis of this ginsenoside produces pharmaceutically active compounds. Caulobacter leidyia GP45, one of the isolates having strong β-glucosidase-producing activity, converted ginsenoside Rb1 to the active metabolites by 91%. The structures of the resultant metabolites were identified by NMR. Ginsenoside Rb1 had been consecutively converted to ginsenoside Rd (1), F2 (2) and compound K (3) via the hydrolyses of 20-C β-(1→6)-glucoside, 3-C β-(1→2)-glucoside, and 3-C β-glucose of ginsenoside Rb1. 相似文献
9.
Chen GT Yang M Song Y Lu ZQ Zhang JQ Huang HL Wu LJ Guo DA 《Applied microbiology and biotechnology》2008,77(6):1345-1350
Preparative-scale fermentation of ginsenoside Rb1 (1) with Acremonium strictum AS 3.2058 gave three new compounds, 12β-hydroxydammar-3-one-20 (S)-O-β-d-glucopyranoside (7), 12β, 25-dihydroxydammar-(E)-20(22)-ene-3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (8), and 12β, 20 (R), 25-trihydroxydammar-3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranoside (9), along with five known compounds, ginsenoside Rd (2), gypenoside XVII (3), ginsenoside Rg3 (4), ginsenoside F2 (5), and compound K (6). The structural elucidation of these metabolites was based primarily on one- and two-dimensional nuclear magnetic resonance
and high-resolution electron spray ionization mass spectra analyses. Among these compounds, 2–6 are also the metabolites of ginsenoside Rb1 in mammals. This result demonstrated that microbial culture parallels mammalian metabolism; therefore, A. strictum might be a useful tool for generating mammalian metabolites of related analogs of ginsenosides for complete structural identification
and for further use in pharmaceutical research in this series of compounds. In addition, the biotransformation kinetics was
also investigated. 相似文献
10.
Larvicidal and antifeedant activity of some plant-derived compounds to Lymantria dispar L. (Lepidoptera: Limantriidae) 总被引:1,自引:0,他引:1
Kostić M Popović Z Brkić D Milanović S Sivcev I Stanković S 《Bioresource technology》2008,99(16):7897-7901
Ethanol solutions of essential oil of Ocimum basilicum and its main component, linalool (both isomer forms), all in three concentrations, as well as botanical standard Bioneem (0.5%), were tested for their toxicity and antifeedant activity against the second instar gypsy moth larvae in the laboratory bioassay. The essential oil of O. basilicum was subjected to gas chromatography analysis, and totally 37 compounds were detected, of which linalool was predominantly present. All tested solutions showed low to moderate larvicidal effect in both residual toxicity test and in chronic larval mortality bioassay. Chronic mortality tests showed that obtained mortality was a consequence of starving rather than ingestion of treated leaves. However, antifeedant index achieved by application of tested solutions in feeding choice assay was remarkable. Foliar application of all tested compounds deterred feeding by L2 in the same percent as Bioneem. Antifeedant index was relatively high at all tested treatments (85-94%); moreover, the larval desensitization to repelling volatiles has not occurred after five days of observation. Low toxic and high antifeedant properties make these plant-derived compounds suitable for incorporation in integrated pest management programs, especially in urban environments. 相似文献
11.
Jorge M. S. Faria Inês S. Nunes A. Cristina Figueiredo Luis G. Pedro Helena Trindade José G. Barroso 《Biotechnology letters》2009,31(6):897-903
Two oxygen-containing monoterpene substrates, menthol or geraniol (25 mg l−1), were added to Anethum graveolens hairy root cultures to evaluate the influence of the biotransformation capacity on growth and production of volatile compounds.
Growth was assessed by the dissimilation method and by fresh and dry weight measurement. The volatiles were analyzed by GC
and GC–MS. The total constitutive volatile component was composed, in more than 50%, by falcarinol (17–52%), apiole (11–24%),
palmitic acid (7–16%), linoleic acid (4–9%), myristicin (4-8%) and n-octanal (2-5%). Substrate addition had no negative influence on growth. The relative amount of menthol quickly decreased
48 h after addition, and the biotransformation product menthyl acetate was concomitantly formed. Likewise, the added geraniol
quickly decreased over 48 h alongside with the production of the biotransformation products. The added geraniol was biotransformed
in 10 new products, the alcohols linalool, α-terpineol and citronellol, the aldehydes neral and geranial, the esters citronellyl,
neryl and geranyl acetates and linalool and nerol oxides.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Liriomyza sativae Blanchard and Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae) are two invasive flies in China that have caused economical damage on vegetables and ornamental plants. In this article, we report the profiles of emitted volatiles from healthy, mechanically damaged, and leafminer-damaged bean, Phaseolus vulgaris L., plants. Among 25 emitted volatiles identified, (E)-2-hexen-1-al, (3E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), (Z)-3-hexenyl acetate, (Z)-3-hexen-1-ol, (syn)- and (anti)-2-methylpropanal oxime, (syn)-2-methylbutanal oxime, linalool, and (E,E)-α-farnesene were consistently released from damaged bean plants. Combined amounts of these nine compounds made up more than 70% of the total volatiles emitted from each treatment. No qualitative differences in volatile emission were found between bean plants damaged by the two fly species; however, amounts of several major compounds induced by L. huidobrensis damage were significantly higher than those from plants damaged by L. sativae. The mechanically damaged plants released a higher proportion of green leaf volatiles than plants in the other treatments, whereas leafminer-damaged plants produced more terpenoids and oximes. Furthermore, the volatile profiles emitted from plants, damaged by adult leafminers, by second instar larvae, and even the plants with empty mines left by leafminer larvae (the pupal stage) were significantly different. The identification of volatile oximes released from damaged plants was confirmed and is discussed in a behavioral and biological control context.Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users. 相似文献
13.
Christian Abel Maria Clauss Andrea Schaub Jonathan Gershenzon Dorothea Tholl 《Planta》2009,230(1):1-11
Volatile organic compounds have been reported to serve some important roles in plant communication with other organisms, but
little is known about the biological functions of most of these substances. To gain insight into this problem, we have compared
differences in floral and vegetative volatiles between two closely related plant species with different life histories. The
self-pollinating annual, Arabidopsis thaliana, and its relative, the outcrossing perennial, Arabidopsis lyrata, have markedly divergent life cycles and breeding systems. We show that these differences are in part reflected in the formation
of distinct volatile mixtures in flowers and foliage. Volatiles emitted from flowers of a German A. lyrata ssp. petraea population are dominated by benzenoid compounds in contrast to the previously described sesquiterpene-dominated emissions
of A. thaliana flowers. Flowers of A. lyrata ssp. petraea release benzenoid volatiles in a diurnal rhythm with highest emission rates at midday coinciding with observed visitations
of pollinating insects. Insect feeding on leaves of A. lyrata ssp. petraea causes a variable release of the volatiles methyl salicylate, C11- and C16-homoterpenes, nerolidol, plus the sesquiterpene (E)-β-caryophyllene, which in A. thaliana is emitted exclusively from flowers. An insect-induced gene (AlCarS) with high sequence similarity to the florally expressed (E)-β-caryophyllene synthase (AtTPS21) from A. thaliana was identified from individuals of a German A. lyrata ssp. petraea population. Recombinant AlCarS converts the sesquiterpene precursor, farnesyl diphosphate, into (E)-β-caryophyllene with α-humulene and α-copaene as minor products indicating its close functional relationship to the A. thaliana AtTPS21. Differential regulation of these genes in flowers and foliage is consistent with the different functions of volatiles
in the two Arabidopsis species. 相似文献
14.
Terhi Vuorinen Anne-Marja Nerg Leena Syrjälä Petri Peltonen Jarmo K. Holopainen 《Arthropod-Plant Interactions》2007,1(3):159-165
The production of volatile organic compounds (VOCs) through the activation of different signal-transduction pathways may be
induced in various biotic and abiotic stress situations having importance e.g. in insect and disease resistance. We compared
the emission of VOCs emitted from silver birch Betula pendula Roth (clones 4 and 80) twigs damaged either by larvae of Epirrita autumnata, or infected with pathogenic leaf spot causing fungus Marssonina betulae. We also analysed whether local herbivore damage can systemically induce the release of VOCs from the undamaged top of same
sapling. The emissions of methylsalicylate (MeSA), (Z)-ocimene, (E)-β-ocimene, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and linalool were induced from the twigs after 72 h feeding damage by E. autumnata larvae. However, 48 h feeding damage did not induce rapid systemic release of VOCs from undamaged top leaves of the same
twigs. Pathogen-infected birch twigs had significantly greater emission of (Z)-ocimene and (E)-β-ocimene than intact control twigs. The emission of DMNT was not significantly induced and MeSA was not found at all after
pathogen infection, both being significantly different from herbivore damaged twigs. According to our results leaf fungal
pathogen induces VOC emission profile differs from that of arthropod herbivore-damaged leaves, suggesting that birch is able
to transmit parasite-specific information via VOC emissions to conspecifics and natural enemies of herbivores.
Handling editor: Yvan Rahbé 相似文献
15.
Anna Napierała-Filipiak Antoni Werner Marek Mardarowicz Jan Gawdzik 《Acta Physiologiae Plantarum》2002,24(2):137-143
The effect of Paxillus involutus, Laccaria laccata, Suillus luteus, S. bovinus, Hebeloma crustuliniforme and a strain of the ectendomycorrhizal fungus Mrg X (Ascomycotina) on the content of volatile organic compounds in roots of Pinus sylvestris seedlings grown in vitro was investigated. Volatile compounds extracted with a supercritical fluid extraction were primarily terpenes and sesquiterpenes
and qualitatively were the same in roots of mycorrhizal and nonmycorrhizal plants. The major monoterpenes were α-pinene, Δ3-carene and β-pinene. Inoculation of plants with the fungi resulted in statistically non-significant increases in the total
amount of the volatiles. The mycorrhizal fungi showed diversified effect on the concentrations of several terpenoids. 相似文献
16.
CHEN XiaoBo ZHAO XiaoHui ZHANG JianPing LI LiangBi & KUANG TingYun 《中国科学:生命科学英文版》2007,50(4):505-510
The singlet excited state lifetime of the chlorophyll a (Chi a) in cytochrome b6f (Cyt b6f) complex was reported to be shorter than that of free Chl a in methanol, but the value was different for Cyt b6f complexes from different sources (~200 and ~600 ps are the two measured results). The present study demonstrated that the singiet excited state lifetime is associated with the detergents n-dodecyl-β-D-maltoside (DDM) and n-octyl-β-D-glucopyranoside (β-OG), but has nothing to do with the different sources of Cyt b6f complexes. Compared with the Cyt b6f dissolved in β-OG, the Cyt b6f in DDM had a lower fluorescence yield, a lower photodegradation rate of Chl a, and a shorter lifetime of Chl a excited state. In short, the singlet excited state lifetime, ~200 ps, of the Chl a in Cyt b6f complex in DDM is closer to the true in vivo. 相似文献
17.
D. Hernández-Rodríguez J. E. Sánchez M. G. Nieto F. J. Márquez-Rocha 《World journal of microbiology & biotechnology》2006,22(7):753-760
Summary Endosulfan is an insecticide used on many vegetable crops. In mushroom cultivation, vegetable materials used as a growth substrate
may contain residues of endosulfan that may accumulate in the final mushroom biomass. After preparing the substrate, it is
subjected to pasteurization and/or composting and then inoculated with the desired fungus. The purpose of this research was
to determine the rate and extent of endosulfan reduction from a grass substrate that was either composted or sterilized by
autoclaving. In addition, the rate and extent of removal of endosulfan from substrate colonized with Pleurotus pulmonarius was determined. The degradation of 65 mg/kg endosulfan was analyzed on both, the substrate preparation and the culture of
P.
pulmonarius on the grass Digitaria
decumbens. During composting in presence of Ca(OH)2 for 120 h, the concentrations of α and β endosulfan were reduced by 61.4 and 49.5% respectively, significantly higher compared
with the control (without Ca(OH)2,) in which the reduction was 38.5%. After sterilization the concentration of α and β endosulfan was reduced by 84.8 and 87.5%
respectively. After the colonization of substrate by P. pulmonarius (15 days after spawning) α and β endosulfan were reduced by 96% and at the end of cultivation (35 days after spawning) were
reduced by 99%. When carpophores were analyzed, residues of α and β endosulfan were observed between 0.019–0.084 mg/kg. The
results showed that α and β endosulfan were partially removed during the preparation of substrate and entirely eliminated
during fungal colonization on the substrate. 相似文献
18.
The instability of cytochrome b
6
f complex in detergent solutions is a well-known problem that has been studied extensively, but without finding a satisfactory
solution. One of the important reasons can be short of the useful method to verify whether the complex suspended in different
detergent is in an intact state or not. In this article, a simple and effective assay for stability of the complex was proposed
based on the investigation on the different effects of the two detergents, n-octyl-β-d-glucopyranoside (OG) and dodecyl-β-d-maltoside (DDM), on the properties of the complex. DDM stabilizes the complex preparation more effectively whereas OG denatures
the interactions of the heme groups and pigment molecules with the protein environment, leading to the bleaching of chlorophyll
a induced by addition of hydrogen peroxide. The assay of the use of hydrogen peroxide to characterize the complex by studying
the bleaching of chlorophyll induced by hydrogen peroxide and the peroxidase activity of the complex was discussed. This simple
method will probably be useful to study the stability of the complex.
Xiao-Bo Chen and Xiao-Hui Zhao contributed equally to this work. 相似文献
19.
Beno?t Boachon Robert R. Junker Laurence Miesch Jean-Etienne Bassard René H?fer Robin Caillieaudeaux Dana E. Seidel Agnès Lesot Clément Heinrich Jean-Fran?ois Ginglinger Lionel Allouche Bruno Vincent Dinar S.C. Wahyuni Christian Paetz Franziska Beran Michel Miesch Bernd Schneider Kirsten Leiss Danièle Werck-Reichhart 《The Plant cell》2015,27(10):2972-2990
The acyclic monoterpene alcohol linalool is one of the most frequently encountered volatile compounds in floral scents. Various linalool oxides are usually emitted along with linalool, some of which are cyclic, such as the furanoid lilac compounds. Recent work has revealed the coexistence of two flower-expressed linalool synthases that produce the (S)- or (R)-linalool enantiomers and the involvement of two P450 enzymes in the linalool oxidation in the flowers of Arabidopsis thaliana. Partially redundant enzymes may also contribute to floral linalool metabolism. Here, we provide evidence that CYP76C1 is a multifunctional enzyme that catalyzes a cascade of oxidation reactions and is the major linalool metabolizing oxygenase in Arabidopsis flowers. Based on the activity of the recombinant enzyme and mutant analyses, we demonstrate its prominent role in the formation of most of the linalool oxides identified in vivo, both as volatiles and soluble conjugated compounds, including 8-hydroxy, 8-oxo, and 8-COOH-linalool, as well as lilac aldehydes and alcohols. Analysis of insect behavior on CYP76C1 mutants and in response to linalool and its oxygenated derivatives demonstrates that CYP76C1-dependent modulation of linalool emission and production of linalool oxides contribute to reduced floral attraction and favor protection against visitors and pests. 相似文献
20.
Elena Antoshina Lawrence E. Ostrowski 《In vitro cellular & developmental biology. Animal》1997,33(3):212-217
Summary We are studying the regulation of ciliated cell differentiation using an in vitro model of tracheal regeneration. Previously, we reported that removal of growth stimulating compounds such as epidermal growth
factor (EGF) and cholera toxin reduced DNA synthesis and cell number while increasing ciliated cell differentiation (Clark
et al., 1995). This result suggested that the induction of growth arrest may stimulate terminal differentiation of airway
epithelial cells into ciliated cells. Transforming growth factor βs (TGFβs) inhibit epithelial cell proliferation and have
also been shown to stimulate epithelial cell differentiation. In this study, the effect of TGFβ1 on growth and ciliated cell differentiation of rat tracheal epithelial (RTE) cells was examined. TGFβ1 inhibited [3H]thymidine incorporation by RTE cells in a dose-dependent manner. A 40% inhibition was observed after a 24-h incubation with
10 pM TGFβ1. Continuous treatment with TGFβ1 (1–50 pM) also reduced cell number during the time when ciliogenesis occurs. This reduction resulted in part from a loss of cells
through exfoliation, in addition to the inhibition of proliferation. The exfoliated cells exhibited several morphological
features characteristic of apoptosis, including shrunken cells, condensed and fragmented nuclei, and intact organelles. In
addition, electrophoretic analysis of genomic DNA analysis isolated from exfoliated cells demonstrated the presence of a nucleosomal
ladder. However, in contrast to the removal of EGF, treatment with TGFβ1 for 7 d did not increase ciliated cell differentiation. TGFβ1 is, therefore, capable of inhibiting proliferation and increasing
apoptosis in RTE cells without stimulating ciliated cell differentiation. 相似文献