Isolation and Molecular Characterization of three virulent actinophages Specific For Streptomyces flavobirens.

Abstract

Three lytic actinophages specific for Streptomyces flavovirens were isolated from Egyptian soil and designated Sf1, Sf2 and Sf3. Phage isolates Sf1, Sf2 and Sf3 produced clear circular single plaques of 2, 1 and 3 mm in diameters, respectively. Thermal inactiva-tion point, dilution end point and longevity in vitro of phages Sf1, Sf2 and Sf3 were found to be 86°C, 82°C and 76°C; 10-5, 10-3 and 10-5; 7, 6 and 7 days, respectively. The isolated phages were found to be stable at different pH levels ranging from 5 to 13. Particle size and morphology of each phage isolate were examined by transmission electron microscopy. The three isolated phages were of head and tail type. They varied in their head diameters and tail lengths. Using RAPD-PCR assay, only seven primers succeeded to generate polymorphic DNA products. Genetic distance value between phages Sf1 and Sf2 was 0.0, phages Sf1 and Sf3 was 1.0 and phages Sf2 and Sf3 was 0.89.