THE STUDY OF FACTORS WHICH INFLUENCE METABOLIC REACTIVATION OF THE ULTRAVIOLET INACTIVATED ESCHERICHIA COLI

Abstract

Exptl. evidence indicates that bacterial inactiva-tion by u. -v. irradiation is a result of an integrated action of all photochemically active photons in which a large number of structural elements and metabolites are altered. Since bacteria are organisms of high organizational and functional complexity, inactivation or killing may be produced by a variety of injury patterns. Evidence suggests that inactivated E. coli. strain B/r can be reactivated by incubation for 24 hrs. at 37[degree]C with various metabolites belonging to the citric acid cycle. 0.1 [image]NaF permits reactivation but prevents bacterial growth and multiplication. Incubation of u.-v. irradiated bacteria with various metabolites produces an increase in viable cell count, the result of cellular recovery induced by metabolite action(restoration of viability was called "metabolic reactivation." ) The most effective reactivation agents are metabolites belonging to the citric acid cycle. Amino acids have only a moderate effect, the exception being alanine. Reduc-ing substances are ineffective in increasing viable cell count. Metabolic reactivation is influenced by incubation temp. and most effective recovery takes place at 37[degree]C. The rate of reactivation is a function of incubation time and the most probable recovery time of the injured cells is 17 hrs. Pyruvate concn. influences reactivation rate, but a saturation effect appears at higher concns. The opt. pH for metabolic reactivation is in the region of neutrality.