BACTERIOPHAGES SPECIFIC TO A PHOSPHATE DISSOLVING BACTERIUM (BACILLUS MEGATERIUM) I- ISOLATION AND CHARACTERIZATION OF BACTERIOPHAGES

Ten isolates of Bacillus megaterium bacteriophages were isolated from a soil sample collected from the Experimental Farm of Faculty of Agric. Minia University. The isolated phages produced single plaques circular in shape, clear in appearance and their diameters ranged from 1 to 3 mm. The isolated bacteriophages were tolerant to pH 4 upto 12. pH 8 was the optimal for the isolated phages. The thermal inactivation point of six phages (Nos. 1,3,4,7, 8 and 9) was 85°C. Whereas, phages Nos. 2,5, 6 and 10 displayed different thermal inactivation point (95°C). Therefore, the ten phages were classified to two groups. Group (A) contained phages Nos. 1,3,4,7, 8 and 9 and group (B) included phages Nos. 2,5, 6 and 10. Sensitivity of phage isolates to U.V. radiation was studied. Phages of group (A) lost their infectivities after exposure for 60 min to U.V., whereas, phages of group (B) inactivated after 40 min. The host range of phages of each group was the same. The electron micrographs of the phages indicated that phages of each group were identical in sizes and morphologies. Therefore, the phages of each group were belonging to one phage type. i.e. the phages of group (A) were one phage type and designated Bm1 and phages of group (B) were another type and designated Bm2.