Uridine diphosphate glucose:fatty acid glucosyl transferase activity of rape (Brassica napus L.) anther tissue.

Particulate fractions from mature rape anther tissue catalysed the incorporation of glucose from UDPglucose into endogenous lipids. The UDPglucose:fatty acid glucosyl transferase was tightly bound to particulates that could be suspended in 0.1% Triton X-100. The apparent Km for UDPglucose was 3.5 . 10(-6) M. In Tris buffer the enzyme has a pH optimum of 8.0 and a temperature optimum of 30 degrees C. In the presence of NaF, the transferase activity was proportional to protein concentration, time, and other variables of the reaction mixture. ADPglucose, GDPglucose, and CDPglucose did not compete with the activity of the UDP-glucose-dependent glucosyl transferase. Gas chromatographic and high performance liquid chromatographic analyses indicated that the endogenous fatty acids glucosylated in vitro had carbon chain lengths of C16 to C20. This is the first report on the biosynthesis of non-phosphorylated glucosyl esters of fatty acids in higher plants.

Isolation and identification of male medfly attractive components inLitchi chinensis stems andFicus spp. stem exudates.

Short-range attraction/feeding stimulation of male Mediterranean fruit flies [Ceratitis capitata (Wiedemann), (Diptera: Tephritidae)] to a stem extract of a host plant,Litchi chinensis Sonn. (Sapindaceae), and to milky exudates from stems of nonhost plants,Ficus retusa L. andF. benjamina L. (Moraceae), were attributed to the presence of the sesquiterpene α-copaene. The presence of α-copaene in the milky exudate from stems ofF. benghalensis L. is also suggested as eliciting similar behavioral responses in male medflies. The presence of minor quantities of α-ylangene in the plants and its contributory effects to the behavioral response of male medflies is discussed. Short-range attraction/feeding stimulation of male medflies to equal amounts of α-ylangene-free α-copaene samples (94.5%+), prepared from α-copaene-enriched angelica seed oil and copaiba oil, respectively, showed no difference in intensity of response. α-Ylangene elicited a slightly less intense response for male medflies than α-copaene.

Structure-activity relationship observations for the bagworm moth pheromone.

Structure-activity relationship (SAR) observations were made for the bagworm moth pheromone, (R)-2-pentyl decanoate, and a series of analogs with modifications in the alcohol portion of the molecule. Observed attractiveness of these analogs was related to molecular structure and their physical attributes using computational chemistry. Electrostatic potential and Van der Waals (VdW) electrostatic coded surface three-dimensional (3D) maps of the molecular mechanics (MM) minimized lowest energy conformation of the pheromone show that size, shape, charge distribution, and chirality of the molecule are related to attractiveness.

Structure-activity relationship observations oftrans-trimedlure enantiomers.

tert-Butyl 4- (and 5-) chloro-trans-2-methylcyclohexane-1-carboxylate (TML), a mixture of four majortrans and four minorcis isomers, is used as an attractant for detecting and monitoring the male Mediterranean fruit fly (medfly),Ceratitis capitata (Wiedemann). The eight isomers (racemic mixtures) were isolated by HPLC, and their relative attractiveness in the field was determined. A quantitative structure-activity relationship (QSAR) was proposed that related a molecular measurement (Å(3)) of the TML structure to male medfly captures. More recently, thetrans-TML enantiomers were synthesized in sufficient quantities for field testing. This paper reports the computer-aided molecular modeling, via Chem-X, of thetrans-TML enantiomers and the staggered and superimposed fitting with the most attractive isomer, (1S,2S,4R)-TML-C, to determine common volumes and surface areas from Van der Waals (VdW) maps. Observations of structure-activity relationships (SAR) are reported for the staggered fittings.

Structure-activity relationship observations for European corn borer moth pheromone and fluoro analogs via computer molecular modeling.

Structure-activity relationship (SAR) observations were made for theZ-type European corn borer moth pheromone, (Z)-11-tetradecen-1-ol acetate, and a series of analogs with fluorination in the alcohol portion of the molecule. The attractiveness of these analogs and the pheromone was compared to the electrostatic potential map of the molecular mechanics (MM) minimized lowest energy conformation for each compound. A critical range of electrostatic potential on the protons of the double-bond appears to be essential for optimal acceptor fit and attractiveness.

Trans-ceralure isomers: Differences in attraction for mediterranean fruit fly,Ceratitis capitata (Wied.) (diptera: Tephritidae).

Differences in attractiveness of four individualtrans isomers of ceralure (CRL) [ethyl 4- (and 5-) iodo-trans-2-methylcyclohexane-1-carboxylate] for male Mediterranean fruit fly,Ceratitis capitata (Wiedemann), were investigated. One of the isomers, CRL-B1 (ethylcis-5-iodo-trans-2-methylcyclohexane-1-carboxylate) was significantly superior to the three othertrans-CRL isomers, CRL, trimedlure (TML) [1,1-dimethylethyl 4- (and 5-) chloro-trans-2-methylcyclohexane-1-carboxylate], and TML-C (1,1-dimethylethyl-cis-4-chloro-trans-2-methylcyclohexane-1-carboxylate) on an equal weight basis.

Reimer-Tiemann adducts as potential insect antifeedant agents Reviewing the structure-activity relationship theory of the antifeedant, warburganal.

Structure-activity relationships of naturally occurring enedials with antifeedant activity againstSpodoptera species have been extended via the synthesis and bioassay of a series of Reimer-Tiemann adducts. The activities attributed to the different chemical structures of these and other analogs interacting with the chemoreceptor site have been observed; a three-pronged mode of substrate binding via aromatic pyrrole formation, Michael addition of free sulfhydryl moieties, and van der Waals interactions of the A ring has been postulated to account for these observations.

Association of beta-agonists with corresponding beta 2- and beta 1-adrenergic pentapeptide sequences.

Synthesized beta 1- and beta 2-pentapeptide sequences corresponding to published adrenoceptor transmembrane activation site subtypes were investigated in vitro for selectivity in association for drug ligands of known selectivity. Both nuclear magnetic resonance spectroscopy and molecular mechanics demonstrated that structural differences among the corresponding pentapeptide activation-site sequences can explain agonist selectivity. Results suggest the agonists bind across the activation site loop on the second transmembrane alpha-helix by dipole/dipole interactions between a ligand and the peptide. Since electrostatic interactions within the membrane may determine the rate of intercellular ion flux, agonist association across the activation site sequence could thereby decrease electrostatic resistance to positive ion flux into the cell. Interactions between the peptides and the ligands may provide insight into the structures and mechanisms involved in association of ligands for the identical sequences on the beta-adrenoreceptors.

Quantitative structure-activity relationships (QSAR) of trimedlure isomers.

Trimedlure (tert-butyl 4- and 5-chloro-cis- andtrans-2-methylcyclohexane-1-carboxylate), a mixture of eight isomers, is used as an attractant for detecting and monitoring the male Mediterranean fruit fly. This paper reports the quantitative structure-activity relationship (QSAR), via CHEMX, of the eight purified isomers (racemic mixtures) of trimedlure. The relationship between structure and attractiveness is demonstrated by utilizing male medfly field catch on day 0 of the individual isomers vs. several molecular descriptors: volume, surface area, a torsion angle, and an interatomic distance.

Identification of sex pheromone of browntail moth,Euproctis chrysorrhoea (L.) (Lepidoptera: Lymantriidae).

A unique sex attractant pheromone was isolated and identified from extracts of ovipositor tips from the female browntail moth (Lepidoptera: Lymantriidae). The pheromone compound, (Z,Z,Z,Z)-7,13,16,19-docosatetraen-1-ol isobutyrate, CH3CH2CH=CHCH2CH=CHCH2CH= CH(CH2)4CH=CH(CH2)6O2CCH(CH3)2, was identified by a combination of gas chromatography, mass spectrometry, and microreactions and was confirmed by synthesis. Traps baited with 5-50 µg of the synthetic pheromone, dispensed from rubber septa treated with an antioxidant and a UV stabilizer, gave male moth captures that were comparable to traps baited with three virgin females. Higher (250 µg) and lower (0.04-2.5 µg quantities of the synthetic pheromone on septa captured somewhat fewer males. Captures were the same for similar quantities of the natural and synthetic pheromone. Minor, inactive components in the tip extract were identified as a mixture of 7- and 8-pentacosanone.