Effect of DDT and Polychlorinated Biphenyls on Cell Population Growth of 'Crithidia Fasciculata', A Flagellated Protozoan.
ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD
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Cell population growth inhibition of Crithidia fasciculata by cell density and cell protein assays after p,p-DDT and polychlorinated biphenyl PCB exposure during exponential growth was analyzed. DDT was apparently not metabolized by this cell. In vitro tests indicated that PCB toxicity increased with decreasing percent chlorination of the mixture. DDT and PCB Aroclor 1254 were calculated to have ID50 values of 425.0 and 10.5 ppm after 12 and 24 hours exposure, their respective period of greatest cell population growth inhibition. Cell density correlated with cell protein as a measure of toxicity for PCB but not for p,p-DDT. A critical concentration range was observed above which the effects were decreased relative to those from lower concentrations employed. The maximum concentration of DDT associated with the cellular compartment occurred by 6 hours of exposure. The sensitivity of C. fasciculata to DDT or PCBs makes it an appropriate model for further xenobiotic-cell interaction studies involving these compounds. An inexpensive and rapid screening method for toxic chemical compounds used by military organizations is of great importance. To meet these requirements, an inexpensive and quick screening method was developed using the protozoan Crithidia fasciculata. Author