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Mycobacteriophages B01, B02a, and B02h were studied with respect to host range, plaque morphology, electron microscopic morphology, nucleic acid composition, one-step growth characteristics, heat inactivation, adsorption, and cross-neutralization.
Phage B01 can be propagated only on Mycobacterium smegmatis. It forms plaques which are clear, circular and consist of several concentric rings. It has an elongated hexagonal head and long non-contractile tail. Its nucleic acid is double-stranded DNA with a 71% GC ratio. In heart infusion broth without Tween-80, phage B01 shows a latent period of 150 min, a rise period of 230 min, and burst size of 61.
Phage B02a is polyvalent, i.e. can be propagated on a number of different mycobacterial hosts. It forms plaques which are hazy and circular. It has a hexagonal head and long non-contractile tail. Its nucleic acid is double-stranded DNA with a 72% GC ratio. In heart infusion broth without Tween-80, phage B02a shows a latent period of 260 min, a rise period of 180 min, and a burst size of 11.
Phage B02h is also polyvalent and forms plaques that are clear and circular. This phage has a hexagonal head and a non-contractile tail. Its nucleic acid is similarly double-stranded DNA with a GC ratio of 72%. It is characterized by a latent period of 320 min, a rise period of 120 min, and a burst size of 20 in heart infusion broth without Tween-80.
The addition of 0.03% Tween-80 as recommended by Bowman (1958) decreases the burst size of all the phages studied. Tween shortens the latent period of phage B01 and B02h and the rise period of phage B01, but lengthens the latent period of phage B02a as well as the rise period of phages B02a and B02h. Heat inactivation of phage B02a is more rapid than that of B01 or B02h at 56 °C and 60 °C. Phage B01 is only slightly more heat sensitive than phage B02h.
All three phages adsorb poorly to their host bacteria. Phage B02h is strongly neutralized by anti-B02a serum, whereas neutralization of phage B02a by anti-B02h serum is considerably weaker. All three phages show some degree of cross neutralization.