The Toxicity of Small Concentrations of Cystine to Acid-producing Bacteria

Abstract

Microbiological assays of cystine, using even the recommended Leuconostoc mesenteroides P-60, are occasionally completely unreliable. At intermediate concns. of cystine (10-30 [mu]g. per 10 ml.) a dip is observed in the standard curve and bacteria in such cultures are seen to be clumped. No satisfactory explanation is advanced for either observation and no basis for a necessary connection is cited.