Ref ID : 2848
Manfred Wanner, Stephanie Esser, and Ralf Meisterfeld; Effects of light, temperature, fertilizers and pesticides on growth of the common freshwater and soil species Cyclopyxis kahli (Rhizopoda, Testacealobosia), interactions and adaptations. Limnologica 24(3):239-250, 1994
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A clone of the testate amoeba Cyclopyxis kahli Deflandre was used to test impact of environmental factors (food, temperature, light, mineral fertilizer, lime, insecticides) on culture under controlled laboratory conditions. Cultures kept at 17 degrees C and sparse food supply entered exponential growth phase later and showed extended generation times as compared to cultures kept at 21 degrees C and provided with food in surplus. The final cell density at the stationary phase was not influenced. Illuminated cultures did not show marked differences in growth characteristics as compared to dark cultures. Direct effects of lime or mineral fertilizer on culture growth were not detected. The two insecticides (pyrethrum, cypermethrin) influenced culture growth significantly. Especially pyrethrum (0.2 µl "Spruzit" per 2 ml culture medium) extended lag time of cultures considerably, but active C. kahli were observed throughout. Therefore maintenance of life functions without reproduction over a long period could be observed. Interactions between temperature and insecticides occured and were also influenced by food concentration. These interactions did not go in the same direction. Cyclopyxis kahli did not show consistent adaptations to treatments, but further investigations are necessary to clarify this point. The investigated clone showed high growth variability under changed environmental conditions. This points to new feasibilities in bioindication, but further research is necessary before these organisms can be used in high-standardized routine assays for cytotoxicology.