Development of a protozoan chemoattraction bioassay for evaluating toxicity of aquatic pollutants

Abstract

A microcapillary assay technique was developed to assess effects of pollutants on the chemoattraction of the ciliate, Tetruhyrnenu pyriformis. Parameters in the protocol such as starvation period, exposure period, and trough design were standardized in an effort to obtain consistent results.Cadmium, phenol, and naphthalene were tested for effects on ciliates' chemoattraction to 0.15% yeast extract. All three toxicants inhibited chemoattraction; cadmium had the greatest effect, followed by naphthalene and phenol, respectively. The percent inhibition of chemoattraction for each concentration was used to determine EC50 values for both 1 and 5 h exposures. Results show that the chemoattraction assay may provide a rapid, inexpensive, and sensitive asessment of aquatic toxicity. Inclusion of a protozoan assay fills the existing taxonomic gap in the routine battery of toxicity tests used for many hazard evaluations.

Toxicity Assessment of 16 Inorganic Environmental Pollutants by Six Bioassays

“…This study demonstrates that murine fibroblasts, such as L-929, can be a successful substitute for the rodent laboratory models (such as rat or mouse) for screening study. Moreover, numerous studies have demonstrated that the protozoa T. pyriformis is also a convenient model for the toxicological evaluation of pharmaceutical drugs (Yoshioka and Ose, 1993), organic substances (Schultz et al, 1990;Yoshioka and Ose, 1993), inorganic substances (Bringhmann and Kuhn, 1980;Nilsson, 1989;Roberts and Berk, 1990), and water (Slabbert and Maree, 1986;Sauvant et al, 1994); thus, it has been proposed as the reference test system by the U.S. Environmental Protection Agency (Greenberg et al, 1992).…”

Use of the Ciliated Protozoan Tetrahymena pyriformis for the Assessment of Toxicity and Quantitative Structure–Activity Relationships of Xenobiotics: Comparison with the Microtox Test

“…With a pH of 6.5 to 7.0, its generation time is approximately 3 h, so the e!ects of pollutants on certain physiological and metabolic processes can be studied through several generations. Several test methods for xenobiotic toxicity using this ciliate have been proposed (Roberts and Berk, 1990;Noever et al, 1994;Sauvant et al, 1995;Bearden et al, 1997;Hegyesi and Csaba, 1997;Larsen et al, 1997). It has been acknowledged as an e$cient test organism for the detection of pollutant in aquatic ecosystems (Cronin et al, 1991).…”

Characterization of copper resistant ciliates: Potential candidates for consortia of organisms used in bioremediation of wastewater

“…It has been acknowledged as an efficient test organism for the detection of pollutant in aquatic ecosystems (Cronin et al, 1991). Several test methods for xenobiotic toxicity using this ciliate have been proposed (Roberts and Berk, 1990;Noever et al, 1994;Sauvant et al, 1995;Larsen et al, 1997). Among the five ciliates tested in this study for copper uptake from the medium, RT-1 and T. thermophila showed greater efficiency than the others.…”