Abstract
Summary and Conclusions
1. A number of organisms whose tryptophane and nicotinic acid requirements are known were tested for possible inhibition by indoleacetic acid and reversal by nicotinic acid and tryptophane in chemically defined media.
2. Escherichia coli, Lactobacillus arabinosus 17-5, L. casei, Streptococcus faecalis R, and Aerobacter aerogenes were inhibited by concentrations of indoleacetic acid of one mg/ml Occasionally slight inhibitions were noted at 0.1 mg/ml levels.
3. No significant relief of inhibition was obtained with either nicotinic acid or tryptophane
4. Staphylococcus aureus and Mycobacterium tuberculosis (607) were not inhibited by indoleacetic acid at the concentrations studied.
5. Fairll consistent stimulation at 0.1 mg/ml levels of indoleacetic acid were obtained with L. arabinosus and L. casei in the presence of limiting concentrations of tryptophane.
6. The significance of these results in relocation to possible metabolite-antagonist relationship between indoleacetic acid and tryptophane or nicotinic acid is discussed.
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