Incorporation of 14C-labelled Components of Escherichia coli and of Amino Acids by Isotricha intestinalis and Isotricha prostoma from the Sheep Rumen

Abstract

Studies on the activities of suspensions of I. intestinalis and L_ prostoma freshly isolated from sheep rumen and washed almost free from bacteria were made by using [Cl4]-amino-acids and Cl4-labelled E. coli. Bacteria were taken up by the protozoa at an approximately linear rate of up to 3000 bacteria/protozoon/hr. for 24 hr., after which time at least 40% of the bacterial C was no longer in the form of whole bacteria. Amino-acids supplied to the protozoa, either free in the medium or as intact bacteria, were incorporated unchanged into protozoal protein. Addition of individual free Cl2-amino-acids to the medium partially inhibited incorporation into protozoal protein of C14 from E. coli labelled with the C14 form of the same amino acid.