Motility comparisons of two shape-distinctiveEntamoeba variants

Abstract

The motility ofEntamoeba sp. (Laredo isolate, LA) is compared to a colchicine-resistant variant (LACR) derived from it and known to exhibit physiological and morphological differences. Both variants possess contractile elements which in glycerinated cell models were activated by Mg2+-ATP. Short-term experiments indicated that whereas both variants are insensitive to colchicine, treatment with cytochalasin B induces a change in cell shape and loss of adhesiveness in LA cells leaving LACR relatively unaffected. Quantitative analysis of time-lapse cinematographic recordings revealed that the mean relative surface area change of LA cells was 411% per minute with a mean pseudopod extension rate of 103 μm per minute. In contrast, the respective values for LACR cells were 112% per minute und 32 μm per minute. Cytochalasin B treatment reduced the relative surface area change of LA cells by approximately 18-fold with a corresponding reduction in LACR cells of only 1.6-fold. Similarly, cytochalasin B inhibited pseudopod extension by 34 and 1.8-fold in LA and LACR cells respectively. Thus, we have demonstrated a clear difference in both pattern and rate of locomotion of the two variants and have shown that the colchicine resistant variant has also become relatively insensitive to treatment with CB.