Abstract
The lytic bacteriaphage (phage) A2 was isolated from human dental plaques along with its bacterial host. The virus was found to have an icosahedron-shaped head (60±3 nm), a sheathed and rigid long tail (∼175 nm) and was categorized into the family Siphoviridae of the order Caudovirales, which are dsDNA viral family, characterised by their ability to infect bacteria and are nonenveloped with a noncontractile tail. The isolated phage contained a linear dsDNA genome having 31,703 base pairs of unique sequence, which were sorted into three contigs and 12 single sequences. A latent period of 25 minutes and burst size of 24±2 particles was determined for the virus. Bioinformatics approaches were used to identify ORFs in the genome. A phylogenetic analysis confirmed the species inter-relationship and its placement in the family.