EFFECTS OF GRAZING BY THE FREE-LIVING SOIL AMEBAS ACANTHAMOEBA-CASTELLANII, ACANTHAMOEBA-POLYPHAGA, AND HARTMANNELLA-VERMIFORMIS ON VARIOUSBACTERIA

Cultures of 10 different bacteria were used to serve as food sources f or axenically grown Acanthamoeba castellanii, Acanthamoeba polyphaga, and Hartmannella vermiformis. The nonpigmented enterobacteriaceae Esch erichia coli K-12 and Klebsiella aerogenes appeared to be excellent fe ed to all three amoebae. Hardly any growth or ammonium production was observed in tests with Chromatium vinosum and Serratia marcescens, whi ch share the presence of pigmented compounds. Distinct differences in net ammonium production were detected and were correlated to the amoeb al growth yield. In general, growth of amoebae and ammonium production increased in the order A. polyphaga, A. castellanii, and H. vermiform is.