An electron-microscopic study of methionine deficient Escherichia coli

Abstract

The morphology of E. coli K-12 (mutant 58/161 of Reubner) grown in a simple salt and glucose solution containing various concentrations of L-methionine and also in nutrient broth has been determined by examining electron micrographs of thin sections of osmium-fixed bacteria. The morphology of the organisms grown in high concentrations of methionine and in broth was similar. Bacteria grown in methionine deficient media contained numerous round, apparently hollow vesicles of 600 A diameter in their cytoplasm. The relationship of these vesicles to previously described cytoplasmic structures has been discussed.