Abstract: A selection of mechanistically diverse substituted pyridines were tested in the Tetrahymena pyriformis population growth impairment assay. The response-surface approach was used to derive multiple-regression type structure-toxicity relationships between T. pyriformis population growth impairment toxicity data (log(IGC(-1)(50)) and the 1-octanol/water partition ...

Abstract: The relative toxicity of selected industrial organic chemicals was secured from the literature for the static 48-h Tetrahymena pyriformis 50% population growth impairment and the flow-through 96-h Pimephales promelas 50% mortality endpoints. Chemicals were selected to represent the nonpolar narcosis (aliphatic alcohols and aliphatic ketones) and polar narcosis ...

Abstract: The toxicities of 34 benzonitriles to Tetrahymena pyriformis have been measured. Structure-activity relationships indicate that for these compounds different mechanisms of toxic action are taking place dependent on the nature of the substituent. Benzonitrile itself, some halogenated and the toluene derivatives model as non-polar narcotics; more polar substituents ...

Abstract: The aim of this investigation was to develop a strategy for the formulation of a valid ecotoxicological-based QSAR while, at the same time, minimizing the required number of toxicological data points. Two chemical selection approaches-distance-based optimality and K Nearest Neighbor (KNN), were used to examine the impact of the number of compounds used in the ...

Abstract: We present the results of an investigation into the use of a probabilistic neural network (PNN) based methodology to model the 48-60-h ICG50 (inhibitory concentration for population growth) sublethal toxicity to the ciliate Tetrahymena pyriformis. The information fed into the neural network is solely based on simple molecular descriptors as can be derived from ...

Abstract: A short-term, static protocol using the common freshwater ciliate Tetrahymena pyriformis (strain GL-C) is reported. The 50% impairment growth concentration (IGC 50) is the endpoint of choice. Cultures are reared in 50 mL of a semi defined medium in 250-mL Erlenmeyer flasks. Definitive test replicates consist of a minimum of 5 different concentrations of each ...

Abstract: A diverse series of amides were evaluated for aquatic toxicity (IGC(50)) assessed in the Tetrahymena pyriformis population growth impairment assay and for reactivity (EC(50)) with the model soft nucleophile thiol in the form of the cysteine residue of the tripeptide glutathione. All alkylamides along with some halo-substituted amides are well predicted by the ...

Abstract: A series of eleven nitrogen-containing heterocyclic compounds, which may be potentially associated with aqueous effluents from coal conversion technologies, were examined to determine the relationships between theirn-octanol/H2O partition coefficients, molecular weights, boiling points, and their toxicity monitored as reproduction impairment toTetrahymena ...

Abstract: Thirteen dinitrogen-containing cyclic compounds were examined to determine the relationship between selected structural and physicochemical parameters and impairment to population growth of the common ciliateTetrahymena pyriformis. Under static conditions all compounds tested are persistent in aqueous solution. Both an increase in methyl substitution and an ...