Evaluation of chitinase as synergist in the management of tick

Abstract

Chitinases play an important role in tick physiology and also have a proven role as bioacaricide. In the current study, an effort was made to amplify chitinase 1 genes of R. sanguineus and R. (B.) microplus from the pre-hatch stage of their eggs. The degenerative primers designed to amplify Haemaphysalis longicornis chitinase 1 gene failed to amplify. Amplification of putative chitinases of R. sanguineus and R. (B.) microplus ticks was attempted by designing a new set of primers for the reference sequences and amplicons of R. sanguineus and R. (B.) microplus chitinases were observed at 1320 and 1305 bp respectively. newlineHistopathology of the ticks exposed to chitinases did not reveal any changes in the cuticular surface in comparison to the control. Spinosad treatment resulted in midgut degeneration, oocytes vacuolation and swollen trachea with detached taenidia. The pre-exposure of the expressed chitinases prior to Spinosad treatment did not show any synergism as there were no difference in the histopathological changes in comparison to the Spinosad treatment alone. Scanning electron microscopy also showed no changes in the ticks exposed to expressed chitinase in comparison to the control ticks. newline