Isolation and Characterization of Phages Infecting Bacillus subtilis

Bacteriophages have been suggested as an alternative approach to reduce the amount of pathogens in various applications. Bacteriophages of various specificity and virulence were isolated as a means of controlling food-borne pathogens. We studied the interaction of bacteriophages with Bacillus species, which are very often persistent in industrial applications such as food production due to their antibiotic resistance and spore formation. A comparative study using electron microscopy, PFGE, and SDS-PAGE as well as determination of host range, pH and temperature resistance, adsorption rate, latent time, and phage burst size was performed on three phages of the Myoviridae family and one phage of the Siphoviridae family which infected Bacillus subtilis strains. The phages are morphologically different and characterized by icosahedral heads and contractile (SIO Phi, SUB omega, and SPO sigma phages) or noncontractile (AR pi phage) tails. The genomes of SIO Phi and SUB omega are composed of 154 kb. The capsid of SIOF is composed of four proteins. Bacteriophages SPO sigma and AR pi have genome sizes of 25 kbp and 40 kbp, respectively. Both phages as well as SUB.. phage have 14 proteins in their capsids. Phages SIO Phi and SPO sigma are resistant to high temperatures and to the acid (4.0) and alkaline (9.0 and 10.0) pH.