Development of similar methodologies for evaluating the toxicity of environmental contaminants with fish cell lines and Tetrahymena

Viability assays were sought that could be used on animal cells in culture and on ciliated protozoa. Three fluorescent dyes effectively detected a loss of viability in cultures of three mammalian cell lines (H4IIE, CaCo2, and HepG-2), two fish cell lines (RTgill-W1 and RTL-W1), and a ciliated protozoan, Tetrahymena thermophila, after exposure to Triton X-100, which was the model toxicant.; A method for presenting toxicants to Tetrahymena in multiple cultures, as has been done for decades with animal cell cultures, was developed. Although ciliated protozoa, such as Tetrahymena, have many desirable properties as toxicological test organisms, their attributes could be better realized if multiple cultures could be simultaneously exposed to toxicants, quickly washed to terminate toxicant exposure, and conveniently evaluated for changes in cellular functions. Therefore, multiwell filter plates (MWFP), manufactured primarily for biochemical applications, were used to expose T. thermophila to copper or Triton X-100 and compared to exposure in microcentrifuge tubes (MCT).; Fish cell lines and ciliates are potential alternatives to whole animals in testing environmental samples for toxicity, two cell lines from rainbow trout, RTgill-W1 and RTL-W1, and the ciliate, Tetrahymena thermophila , were compared for their sensitivity to the toxicity of five metals that are commonly found in mining effluents: copper, cadmium, zinc, nickel, and iron. Adding copper to growth medium for either cell system failed to elicit toxicity. Therefore, metal exposures were done in simple buffers, which allowed all metals to exert toxicity, except for nickel on fish cells. Cell viability was measured successfully with AB for energy metabolism and CFDA-AM for membrane integrity, whereas neutral red uptake, which was quantified fluorometrically, gave confounding results with copper. Cadmium was the most toxic metal to Tetrahymena and killed the ciliate at approximately a 10-fold lower concentration than needed to kill fish cells. Fish cells were more sensitive than Tetrahymena to the cytotoxic action of zinc. Copper and iron were cytotoxic to fish cells and Tetrahymena at similar concentrations. The differing metal sensitivities could be exploited by using the two cell systems as part of a battery of tests for evaluating effluent toxicity quickly and inexpensively. (Abstract shortened by UMI.)...