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Toxicity assessment of mono‐substituted benzenes and phenols using a Pseudomonas initial oxygen uptake assay
Author(s) -
Huang DedShih,
Whang ThouJen,
Cheng FeiChen,
Wu YaPing,
Wang YiTing,
Luo WenI,
Wang YaneShih
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/04-212r.1
Subject(s) - pseudomonas putida , phenols , chemistry , toxicity , quantitative structure–activity relationship , pseudomonas , stereochemistry , biochemistry , organic chemistry , biology , bacteria , enzyme , genetics
A methodology is presented for assessing the toxicity of chemical substances through their inhibitory action toward the Pseudomonas initial oxygen uptake (PIOU) rate. The current studies reveal that the PIOU assay is rapid, cost‐efficient, and easy to perform. The oxygen uptake rate was found to be associated with a putative benzoate transporter and highly dependent on benzoate concentration. The putative benzoate transporter has been shown to follow Michaelis–Menten kinetics. Most phenols were found to be noncompetitive inhibitors of the benzoate transporter. The inhibition constant ( K i ) of these noncompetitive inhibitors can be related to the concentration causing 50% oxygen uptake inhibition in Pseudomonas putida . Modeling these data by using the response–surface approach leads to the development of a quantitative structure–activity relationship (QSAR) for the toxicity of phenols ((1/ K i ) = –0.435 (±0.038) lowest‐unoccupied‐molecular orbital + 0.517 (±0.027)log K OW −2.340 (±0.068), n = 49, r 2 = 0.930, s = 0.107, r 2 adj = 0.926, F = 303.1). A comparison of QSAR models derived from the K i data of the PIOU method and the toxicity data of 40‐h Tetrahymena pyrifomis growth inhibition assay (Tetratox) indicated that there was a high correlation between the two approaches ( r 2 = 0.925).