VEGFR2 (Phospho-Tyr951) ELISA Kit

BACKGROUND The pyrethroid deltamethrin is used to treat infestations of farmed salmon by parasitic salmon lice,Lepeophtheirus salmonis(Kroyer). However, the efficacy of deltamethrin for salmon delousing is threatened by resistance development. In terrestrial arthropods, knockdown resistance (kdr) mutations of the voltage-gated sodium channel (Na-v), the molecular target for pyrethroids, can cause deltamethrin resistance. A putativekdrmutation of anL. salmonissodium channel homologue (LsNa(v)1.3 I936V) has been identified previously. At the same time, deltamethrin resistance ofL. salmonishas been shown to be inherited maternally and to be associated with mitochondrial DNA (mtDNA) mutations. This study assessed potential roles of the above putativekdrmutation as a determinant of deltamethrin resistance in laboratory strains and field populations ofL. salmonis. RESULTS The deltamethrin-resistantL. salmonisstrain IoA-02 expresses the LsNa(v)1.3 I936V mutation but was susceptible to the non-ester pyrethroid etofenprox, a compound against which pyrethroid-resistant arthropods are usually cross-resistant if resistance is caused by Na(v)mutations. In a family derived from a cross between an IoA-02 male and a drug-susceptible female lacking thekdrmutation, deltamethrin resistance was not associated with the genotype at the LsNa(v)1.3 locus (P > 0.05). Similarly, in Scottish field populations ofL. salmonis, LsNa(v)1.3 I936V showed no association with deltamethrin resistance. By contrast, genotypes at the mtDNA loci A14013G and A9030G were significantly associated with deltamethrin resistance (P < 0.001). CONCLUSION In the studiedL. salmonisisolates, deltamethrin resistance was unrelated to the LsNa(v)1.3 I936V mutation, but showed close association with mtDNA mutations.

Pesticide resistance is normally associated with genetic changes, resulting in varied responses to insecticides between different populations. There is little evidence of resistance to plant allelochemicals; it is likely that their efficacy varies between genetically diverse populations, which may lead to the development of resistance in the future. This study evaluated the response of Anopheles gambiae (larvae and adults) from spatially different populations to acetone extracts of two botanicals, Piper guineense and Eugenia aromatica. Mosquito samples from 10 locations within Akure metropolis in Southwest Nigeria were tested for variation in susceptibility to the toxic effect of botanical extracts. The spatial distribution of the tolerance magnitude (T.M.) of the mosquito populations to the botanicals was also mapped. The populations of An. gambiae manifested significant differences in their level of tolerance to the botanicals. The centre of the metropolis was the hot spot of tolerance to the botanicals. There was a significant positive correlation between the adulticidal activities of both botanicals and initial knockdown. Hence, knockdown by these botanicals could be a predictor of their subsequent mortality. In revealing variation in response to botanical pesticides, our work has demonstrated that any future use of botanicals as alternative environmentally friendly vector control chemicals needs to be closely monitored to ensure that resistance does not develop.