IDENTITY OF DNA FROM ESCHERICHIA COLI AND FROM ITS RESPIRATORY-DEFICIENT MUTANT, AND THE PHYSIOLOGICAL SIMILARITY OF THE LATTER WITH LACTOBACILLI

Abstract

The respiratory-deficient mutant H₇, obtained by Beljanski from Monod's strain of Escherichia coil, differs in several respects from the parent strain. Comparison of the DNAs from the two cultures has revealed complete homology. Physiologically, the mutant resembles the homofermentative lactobacilli; it does not contain catalase or cytochromes, grows better in the absence than in the presence of air, produces lactic acid from glucose even under aerobic conditions, and requires amino acids for growth. These properties are discussed in relation to the respiratory deficiency, as is their bearing on the evolutionary status of the lactobacilli.