ABSTRACT
@#Plants contain bioactive compounds and are constantly explored as safer alternatives to conventional insecticides. Despite numerous studies on many plants, information on the insecticidal potential of underutilised plants like tiger nut, Cyperus esculentus L., are scant, although their pharmacological potentials are well known. Hence, this study investigated the larvicidal potential of crude aqueous extracts of two C. esculentus varieties (black and yellow) on the mosquitoes Aedes aegypti (L.) and Culex quinquefasciatus (Say). Mosquito larvae were exposed to C. esculentus crude extracts using the larval bioassay technique of the World Health Organization. Differential larvicidal responses were observed in the test mosquitoes and extracts of Black Dried Tiger nuts (BDT) were more larvicidal than Yellow Dried Tiger nuts (YDT). Acute larval toxicity of the extracts was more pronounced on Cx. quinquefasciatus than Ae. aegypti. The results indicate the potential of C. esculentus (particularly BDT) as a source of mosquito bioinsecticide and merits further studies as a safer alternative to conventional insecticide-based vector control.
ABSTRACT
Glutathione S-transferases (GSTs) are multifunctional enzymes involved in detoxification of xenobiotic compounds in many insect groups. This work investigated the expression of GSTs in Aedes albopictus by using affinity chromatography and proteomic analysis. The study compared the expression of GSTS isoforms in larvae of three Ae. albopictus strains (susceptible (VCRU) strain, field Kuala Lumpur (KL) strain and laboratory permethrintreated strain). The study demonstrated that the expression of sixteen isoforms (GSTS1-1, GSTS1-4, GSTS1-3, GSTS1-4, GSTD1-3, GSTD1-2, GSTD1-5, GSTD1-6, GSTD1-7, GSTD1-8, GSTD1-9, GSTD1-10, GSTD1-11, GSTT, GSTD1-12, and GSTD1-13) were significantly increased in the field KL strain (p0.05). However, while comparing the expression of GST isoforms in field KL larvae and laboratory permethrin-treated strain, the same pattern was observed for all the GSTs especially for Theta and Sigma class (p>0.05). In Delta class, only GSTD1-1, GSTD1-9, GSTD1-11, GSTD1- 12 and GSTD1-13 shows significant difference in expression between these two strain (p<0.05). This comparative data on GST expression in Ae. albopictus can be useful database to identify possible underlying mechanisms governing insecticide resistance by GSTs.