Ref ID : 7740
M. Pussard and F. Delay; [Dynamique de Population D'amibes Libres Endogees (Amoebida, Protozoa) I. - Evaluation du Degre D'activite en Microcosme et Observations Preliminaires sur la Dynamique de Population de Quelques Especes]. Protistologica XXI(1):5-15, 1985
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Preliminary experiments in Dermamoeba granifera (Thecamoebidae) showed that Cutler's classical procedure (1920) is not suitable for estimating the degree of activity of populations in some amoeba species. The treatment of an earth sample using 2% hydrochloric acid destroys both trophozoites and cysts, which leads to an overestimation of the degree of activity. Trials were conducted to replace the above treatment by desiccation and/or freezing. The ability of some species to go into direct anhydrobiosis (Thecamoeba similis) should be considered when analysis results. Three treatments were chosen: rapide desiccation (1 hour at 40 degrees C), moderate freezing (15 min at -10 degrees C) and a combined treatment successively including rapide desiccation, suspension in water for 30 min, and freezing. Thus, it is possible to evaluate the number of individuals capable of surviving desiccation (anhydrobiosis) or freezing. Therefore, this procedure can be used for analyzing the population dynamics of amoebae. The species studied (Acanthamoeba castellanii, Saccamoeba limax, Dermamoeba granifera and Thecamoeba similis) use highly differing demographic strategies.