Isolation and characterization of bacteriophage BCJA1, a novel temperate bacteriophage active against the alkaliphilic bacterium, Bacillus clarkii

The isolation and characterization of a novel bacteriophage active against the obligately alkaliphilic bacterium Bacillus clarkii is described. The bacteriophage, designated BCJA1, is a member of the Siphoviridae family with a B1 morphology. It possesses an isometric head, which measures 65 nm between opposite apices, and a noncontractile tail of 195 nm length. It had a buoyant density of 1.518g/ml and an estimated particle mass of 37 × 10⁷ daltons. BCJA1 was stable over the pH range of 6-11. A one-step growth experiment conducted at pH 10 demonstrated a latent period of about 40min and a burst size of approximately 40. The purified bacteriophage appeared to consist of 10 proteins with the major head and tail proteins likely to be of molecular weight 36500 and 28000, respectively. The genome size was estimated to be between 32.1 and 34.8kb. The percent G + C content of purified bacteriophage DNA was 45.6. The wildtype bacteriophage is temperate but a clear plaque mutant was isolated.