Isolation of Bacillus thuringiensis from soil and their impact on mosquito larvae

Abstract

Mosquitoes are vectors of various disease causing agents and are responsible for the transmission of pathogens causing more life threatening and debilitating human diseases than any other organism. Over one million people worldwide die from mosquito borne diseases which include Malaria, Chikungunya, Yellow fever and Dengue fever yearly within disease- endemic countries. Continuous use of chemical-based insecticides has resulted in the development of resistance in mosquito and cause detrimental effects on non-target organisms and thus causes human health problems. Bacillus thuringiensis is an important insect pathogen is highly toxic to mosquito larvae and related dipterans. Bacillus thuringiensis during the sporulation phase produces proteinaceous parasporal crystals called as delta-endotoxin. This crystal protein is active in alkaline condition of midgut of insects and gets solubilized  and when activated by intrinsic protease results in an active toxin that selectively binds specific receptor in the cell membrane, leading to pore formation and consequent  insect larvae death. Thus the present study reveals Bacillus thuringiensis to be highly active on mosquito pests and less likely to cause resistance and no effect to non-target animals and is thus considered beneficial to humans in the eradication of Mosquitoes.