Genetic and Biochemical Studies on Mannose-Negative Mutants That Are Deficient in Phosphomannose Isomerase in <i>Escherichia coli</i> K-12

Abstract

Two mannose-negative mutants of Escherichia coli K-12 have been isolated. These mutants are deficient in the ability to synthesize phosphomannose isomerase and capsular polysaccharide when grown on glucose-containing media. Interrupted mating experiments to determine the kinetics of genetic transfer show that the two mannose-negative mutations map together between the histidine and tryptophan regions of the E. coli chromosome.