Discovery of antibacterial activity in crude protein extracts of the eastern subterranean termite, Reticulitermes flavipes

The termites’ innate immune system has been of great interest recently for both isolation of novel antimicrobial compounds and developing more effective approaches to combat the pest. This study determined the antimicrobial activity of R. flavipes cell free extracts of various sizes and investigated whether the antibacterial activity was inducible.  Our results demonstrate that R. flavipes constitutively produce antibacterial protein(s) against Bacillus subtilis. However, when fed with heat-killed Pseudomonas aeruginosa, R. flavipes produced significantly enhanced amounts of anti-Bacillus (10-30 kDa) and anti-Pseudomonas (>30 kDa) proteins. This is the first study to report the existence of antibacterial activity from R. flavipes. Moreover, the data demonstrate that R. flavipes produces antibacterial proteins that are active against both gram-negative and gram-positive bacteria.