Abstract
1. Streptomycin-resistant, chloramphenicol-resistant and strepto-mycin-dependent strains were isolated from a parent strain of E. coli.
2. Total nitrogen, nucleic acid, free amino acid and viable cell number were determined in each strain at various culture stages. Strepto-mycin-resistant and chloramphenicol-resistant strains showed a tendency of increase and decrease in total nitrogen and RNA amounts approximately similar as the parent strain. On the contrary in a streptomyin dependent strain which shows a retarded growth, the total nitrogen and RNA amounts did not increase to the same rate and extent as above and it may be presumably due to the fact that the protein synthesis of the strains would not proceed so sufficiently during the culture stages.
In concluding this paper, I wish to express gratitude to Prof. M. Kuroya for his generous guidance throughout the experiment and for reviewing the manuscript.
