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A homology model of the housefly voltage-gated sodium channel was developed to predict the location of binding sites for the insecticides fenvalerate, a synthetic pyrethroid, and DDT an early generation organochlorine. The model successfully addresses the state-dependent affinity of pyrethroid insecticides, their mechanism of action and the role of(More)
Mutations in the DIIS4-S5 linker and DIIS5 have identified hotspots of pyrethroid and DDT interaction with the Drosophila para sodium channel. Wild-type and mutant channels were expressed in Xenopus oocytes and subjected to voltage-clamp analysis. Substitutions L914I, M918T, L925I, T929I and C933A decreased deltamethrin potency, M918T, L925I and T929I(More)
The essential oil of Hemizygia petiolata Ashby (Lamiaceae) contains high levels (>70%) of the sesquiterpene (E)-beta-farnesene, the alarm pheromone for many economically important aphid species. In order to test the suitability of H. petiolata oil as a source of (E)-beta-farnesene for use in new integrated aphid control strategies, behavioural responses of(More)
Destruxin A, a cyclohexadepsipeptide related to the enniatins and beauvericin, exhibits ionophoric properties. Calcium ion mobilization across liposomal membrane barriers, for example, has been demonstrated using the calcium ion-sensitive dyes Arsenazo III and Fura-2. Initial molecular mechanics/molecular dynamics calculations indicate the potential for(More)
Quantification of artemisinin purity and amount in plant material and extracts to date has been characterized by a considerable inconsistency in values. This is likely to be due to the adoption of varied analytical procedures and use of inappropriate to the specific applications analytical techniques. In this paper we are attempting to further develop(More)
In a previous study, we showed that two alternative exons (G1 and G2 encoding IIIS3-S4) were involved in the differential sensitivity of two cockroach sodium channel splice variants, BgNa(v)1-1 and BgNa(v)2-1 (previously called KD1 and KD2), to deltamethrin, a pyrethroid insecticide (Tan, et al., 2002b. Alternative splicing of an insect sodium channel gene(More)
A structural investigation of autoxidation products of methyl oleate was carried out by gas chromatography-mass spectrometry (GC-MS) of trimethylsilyl (TMS) ether derivatives. GC-MS using computer plots of selected masses afforded structural assignments of GC peaks due to incompletely resolved mixtures. This method provided evidence of epoxy and keto esters(More)
Antibacterial activity in 51 extracts from 29 plant species currently used in traditional medicine in Trinidad and the neighbouring Caribbean islands was tested for by the agar dilution streak method using six bacteria: Escherichia coli, Pseudomonas aeruginosa. Salmonella tophimurium, Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus(More)
Fresh rhizomes of Zingiber officinale (ginger), when subjected to steam distillation, yielded ginger oil in which curcumene was found to be the major constituent. The thermally labile zingiberene-rich fraction was obtained from its diethyl ether extract. Column chromatography of ginger oleoresin furnished a fraction from which [6]-gingerol was obtained by(More)
DDT inhibits Na channel inactivation and deactivation, promotes Na channel activation and reduces the resting potential of Xenopus oocytes expressing the Drosophila para Na channel. These changes are only marginally influenced by the single mutation M918T (super-kdr) but are reduced approximately 10-fold by either the single mutation L1014F (kdr) or the(More)