The metabolism of starch, glucose, amino acids, purines, pyrimidines and bacteria by the rumen ciliate Entodinium simplex.

Abstract

SUMMARY: Washed suspensions of Entodinium simplex grown in vitro and incubated anaerobically engulfed all the types of bacteria tested. At high bacterial densities Klebsiella aerogenes and Proteus mirabilis, two bacteria normally present in the growth medium, were taken up most rapidly. Entodinium simplex utilized bacterial amino acids for the synthesis of protein and no evidence was obtained for appreciable synthesis of protein from carbohydrate. No intercpnversion of amino acids occurred. Free and bacterial adenine, guanine and uracil were incorporated into protozoal nucleic acid: uracil was partially converted into cytosine. Free amino acids and glucose were taken up by the protozoa by two mechanisms, one predominant at high concentrations and the other at low concentrations. Glucose was incorporated, in intact protozoa, into both polysaccharide and bacteria and glucose had to be taken up by the protozoa before it was incorporated into the bacteria.