Cyanophages infecting Anabaena circinalis and Anabaena cylindrica in a tropical reservoir

Abstract

A total of six lytic cyanophages have been isolated from Kranji Reservoir in Singapore. Two cyanophages infected a toxic species of cyanobacterium, A. circinalis, while four cyanophages infected the cyanobacterium A. cylindrica. To obtain the cyanophages that infect A. circinalis and A. cylindrica, two isolation methods were established. Cyanophages infecting A. circinalis were successfully isolated with well assay, and cyaophages infecting A. cylindrica were successfully isolated with double layer plaque assay. These isolation methods resulted in a rapid and significant lytic effect. A. circinalis cyanophage isolates are potential biocontrol of A. circinalis, due to the ability of cyanophage isolates in suppressing the growth of A. circinalis effectively. During the isolation process, we observed that A. cylindrica experienced changes in ag- gregation and algal mat formation when inoculated with the cyanophage isolates.