Abstract: Toxicity to the ciliate Tetrahymena pyriformis (log(IGC(50)(-1))) for 39 halogen-substituted alkanes, alkanols, and alkanitriles were obtained experimentally. Log(IGC(50)(-1)) along with the hydrophobic term, logK(ow) (1-octanol/water partition coefficient) and the electrophilic parameter, E(lumo) (the energy of the lowest unoccupied molecular orbital) were ...

Abstract: Hydrophobic- and electrophilic-dependent structure-toxicity relationships were developed and compared for several mechanisms of toxic action. Potency data included values from the 96-h Pimephales promelas mortality assay, the 40-h Tetrahymena pyriformis population growth inhibition assay, and the 15-min Vibrio fischeri luminescence inhibition assay. In addition ...

Abstract: The aquatic toxicities (log(IGC50-1)) of 22 quinones were evaluated in the static Tetrahymena pyriformis population growth assay. A toxicity in excess of baseline was associated with each chemical eliciting a response. The ortho-quinones were the most toxic; internal quinones, with benzenoid substitution on both sides of the quinoid rings, were not toxic at ...

Abstract: A series of 37 aliphatic and aromatic sulfur-containing compounds were evaluated in 2-day Tetrahymena pyriformis population growth impairment assay. The results indicate that, except for select compounds, the in-ring sulfur-containing compounds, sulfates, sulfites, thiols, sulfones, and sulfoxides model as neutral and noncovalent-reacting narcotics. Abiotic ...

Abstract: Toxicity data collected in a laboratory setting are the primary source of potency information used for regulatory, modeling, or risk assessment purposes. However, the relative reproducibility of such toxicity data is rarely discussed. This study investigated the reproducibility of growth impairment data for the freshwater ciliate Tetrahymena pyriformis exposed ...

Abstract: In the summary/recommendations for the Ecotoxicology Session of TestSmart--A Humane and Efficient Approach to Screening Information Data Sets (SIDS) Data Workshop, it was recommended that more population growth impairment data using Tetrahymena be generated and compared with available lethality data for the fathead minnow. To comply with this recommendation, ...