Isolation of mosquitocidal bacteria (Bacillus thuringiensis, B.sphaericus and B.cereus) from excreta of arid birds.

ABSTRACT

Mosquitocidal bacteria are environmentally friendly alternatives to chemical insecticides for controlling mosquitoes and therefore, there have been tremendous world-wide efforts to identify novel mosquitocidal bacteria from natural environment. In the present study, excreta from arid-birds were analyzed for identifying mosquitocidal bacteria. The selection of sample for bacterial screening is significant, because, arid-birds are the unique living species and gathering the foods from variety of sources from environment. Out of 1000 samples examined, twelve bacterial strains were identified as mosquitocidal and the 16S rRNA gene sequence alignment depicted that these isolates belonged to Bacillus species (Bacillus thuringiensis, B.sphaericus and B.cereus). Toxicity assay against mosquito vectors have shown that these isolates are potential. The B. sphaericus VCRC-B547 (NCBI JN377789) has shown a higher toxicity against Cx. quinquefasciatus, An. stephensi, and Aed. aegypti. Result from SDS-PAGE has shown that there was considerable difference in the protein profiles among the new bacterial isolates. Phylogenetic tree with branch length 0.05 revealed three distinct groups with homology among the closely related Bacillus strains. This study therefore throws considerable interest on the diversity of microbial organisms from arid birds and its application in mosquito control.