The role of Aerobacter sp., Escherichia coli and certain amino acids in the excystment of Schizopyrenus russelli

Abstract

Aqueous extracts of Aerobacter sp. and Escherichia coli have been found to cause excystment of viable sterile cysts of Schizopyrenus russelli. The factors which cause excystment are thermostable. With the aid of paper partition chromatography of the aqueous extract of Aerobacter sp., it has been found that part of the excystment-inducing activity is due to the presence of amino acids, some of which have been identified. Amino acids, sugars, purines, pyrimidines, nucleosides, nucleotides and organic phosphates have been tested for their ability to induce excystment. It has been found that some amino acids and a few nucleotides can cause excystment. The effect of pH, concentration and time on excystment with amino acids has been studied.