[Some physicochemical properties of the dysenteric therapeutic--prophylactic Newcastle phages H-17 and H-18 (Author's transl)].

Some physico-chemical properties of dysentery therapeutic-prophylactic Newcastle-phages H-17 and H-18 were studied. Both phages were shown to be resistant to sodium dodecyl sulphate at room temperature. Phage H-17 at room temperature was completely inactivated and phage H-18 inactivated by 40% by 1 M sodium hydrochloride. Phage H-18 was completely inactivated by 4 M sodium hydrochloride. Morphology and sizes of the phages are described. The buoyant density of phage H-17 was found to be 1.497 g/cm3, and of phage H-18 1.504 g/cm3. DNA of both phages were identified as double-stranded on the basis of the pattern of melting curve, of interaction with formaldehyde and absorption spectrum in solutions with various ionic strengths. The melting point of DNA of phage H-17 is 83.63 degrees C, phage H-18 89.67 degrees.