[Makeup and properties of E. coli cells with a varying level of resistance to tetracycline].

Lipopolysaccharide composition of tetracycline sensitive and resistant strains of E. coli was studied comparatively. It was shown that that resistance of E. coli to tetracycline was probably due to the differences in the lipopolysaccharide component composition of the outer membrane. On the basis of the activity comparison of the Mg2+- and Ca2+-activated ATP-ase of the membrane fraction of the tetracycline sensitive and resistance strains of E. coli it was concluded that the resistance development in the strains tested to tetracycline was not associated with the changes in the ATP-ase activity.