BACTERIOLYTIC ACTIVITIES OF THE FREE-LIVING SOIL AMEBAS, ACANTHAMOEBA-CASTELLANII, ACANTHAMOEBA-POLYPHAGA AND HARTMANNELLA-VERMIFORMIS

Bacteriolytic activities of axenically grown free-living soil amoebae Acanthamoeba castellanii, Acanthamoeba polyphaga and Hartmannella verm iformis towards various Gram-positive and Gram-negative bacteria were determined. A spectrophotometric assay revealed that the specific bact eriolytic activities of both Acanthamoeba species were higher as those of the three Hartmannella strains. Bacillus megaterium, Bacillus subt ilis, Chromatium vinosum, Micrococcus luteus and Pseudomonas fluoresce ns were more easily lysed than the other bacteria tested. Agrobacteriu m tumefaciens, Klebsiella aerogenes and Serratia marcescens were hardl y affected at all by the amoebal bacteriolytic activities. Among the G ram-negative bacteria we observed differences in lysis sensitivity whi le the Gram-positive bacteria tested were sensitive to lysis. Isoelect ric focusing (IEF) gel-electrophoresis in the pH range 3-10 was perfor med to separate the bacteriolytic isoenzymes of amoebae. Bacteriolytic patterns were shown by using an activity assay in which lysis bands w ere formed in the agar/bacteria gel-overlay. The activity assay reveal ed remarkable differences in typical banding patterns for bacteriolyti c activities among amoebae. Distinct differences between typical pI po ints of bacteriolytic activities in Acanthamoeba and Hartmannella were shown. Bacteriolytic activities of Hartmannella were more pronounced and observed in the isoelectric points (pI) range of 4.0-9.3 while for Acanthamoeba the range was pI 4.5-8.9.