Abstract: The aim of the study was to develop quantitative structure-activity relationships (QSARs) for a large group of 77 aromatic aldehydes tested for acute toxicity to the ciliate Tetrahymena pyriformis using mechanistically interpretable descriptors. The resulting QSARs revealed that the 1-octanol/water partition coefficient (log K(ow)), is the most important ...

Abstract: The toxicity data of chemicals common to both the Poecilia reticulata mortality assay and the Tetrahymena pyriformis growth impairment assay were evaluated. Two chemicals were not toxic at saturation in the T. pyriformis assay. In addition, due to abiotic transformation, a third chemical was removed from further consideration. Each chemical was a priori assigned ...

Abstract: The relative biological response (log BR) for each of 30 select substituted phenols and anilines was evaluated using the 48-h Tetrahymena pyriformis population growth test system. Simple linear regression analysis of log BR versus log Kow (1-octanol/water partition coefficient) was used to formulate a quantitative structure-activity relationship (QSAR). The ...

Abstract: Twenty 2- and 3-position derivatives of pyridine (C5H5N) were tested following a short-term static protocol. Biological activity was monitored as population growth of Tetrahymena pyriformis. These data were combined with previously reported data for twenty 4-position derivatives. Structure-activity relationships were examined using Kow as the physicochemical ...

Abstract: Twenty-two four-position derivatives of pyridine (C5H5N) were tested following an acute static regime with biological response being monitored as population growth of Tetrahymena pyriformis. The vinyl derivative was the most active and the hydroxy derivative was the least active. Structure-activity relationships were examined using substituent constants as ...

Abstract: The relative toxicity of 24 selected amines was evaluated in the 48 h Tetrahymena pyriformis static population growth impairment assay and compared with literature data for the 96 h Pimephales promelas flow-through mortality assay. Chemicals selected included normal and branched aliphatic primary amines, 4-position alkyl-substituted primary aromatic amines, ...

Abstract: Toxicity data for 200 substituted benzenes tested in the two-day Tetrahymena pyriformis population growth impairment assay representing the neutral narcosis, polar narcosis, respiratory uncoupling, and weak and strong electrophilic mechanisms of toxic action were evaluated. A quantitative structure-toxicity model correlating toxic potency [log(IGC(50)(-)(1))] ...

Abstract: A diverse set of 60 haloaliphatic compounds were evaluated for reactivity with cysteine thiol groups in the previously described RC(50) assay using glutathione (GSH) as a model nucleophile. Reactivity was quantified by the RC(50) value, the concentration of test compound that produced 50% reaction of the GSH thiol groups in 120 min. Under standard conditions, ...

Abstract: A recently introduced chemoassay has been used to determine second-order rate constants of the electrophile-nucleophile reaction of 15 α,β-unsaturated aldehydes with glutathione. The respective kGSH values vary for more than 3 orders of magnitude, and are within the range determined previously for 31 α,β-unsaturated ketones and esters. Structure-reactivity ...

Abstract: This paper presents a mechanistic analysis of aquatic toxicity data, quantified as pIGC(50) assessed in the 40 h Tetrahymena pyriformis population growth impairment assay, for 40 polyhydroxybenzene derivatives. The toxicity trends of these phenolic compounds have been shown to be consistent with mechanistic organic chemistry principles. Thus, it is shown that ...