Abstract: Eighty 2-, 3-, and 4-position monosubstituted phenols representing various substituents were evaluated for relative toxicity. log IGC50(-1). with a short-term static protocol in the Tetrahymena population growth inhibition bioassay. Quantitative structure-activity relationships (QSAR) were examined using the 1-octanol/water partition coefficient (log Kow ) and ...

Abstract: Reactive toxicity encompasses important endpoints such as skin and respiratory sensitization, hepatotoxicity and elevated acute aquatic toxicity. These adverse effects are initiated by, among others, electrophilic chemicals and those transformed into electrophiles; i.e. non-reactive chemicals activated into reactive electrophilic species by either a biotransformation ...

Abstract: The aim of this work was to develop a high-quality 1-octanol/water partition coefficient-dependent (log P) baseline quantitative structure-activity relationship (QSAR) for the toxicity (log IGC(50)(-1)) of classic non-polar narcotics to Tetrahymena pyriformis, and subsequently use this model to define the domain of applicability for baseline narcosis. The ...

Abstract: The relative toxicity (log IGC50(-1)) of 49 selected aliphatic amines and aminoalkanols was evaluated in the static Tetrahymena pyriformis population growth impairment assay. Excess toxicity, indicated by potency greater than predicted for non-polar narcotic alkanols, was associated with both classes of test chemicals. Moreover, the aminoalkanols were found ...

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 ...