El-Alawi Yousef S, Huang Xiao-Dong, Dixon D George, Greenberg Bruce M
Department of Biology, University of Waterloo, Ontario, Canada.
Environ Toxicol Chem. 2002 Oct;21(10):2225-32.
Sunlight can greatly enhance the toxicity of polycyclic aromatic hydrocarbons (PAHs). Photosensitization reactions (e.g., generation of singlet-state oxygen) and photomodification reactions (e.g., photooxidation of PAHs to more toxic species) are both pathways of photoinduced toxicity of PAHs. Previously, a quantitative structure-activity relationship (QSAR) was developed for PAHs showing that a photosensitization factor (PSF) and photomodification factor (PMF) can be additively combined to describe photoinduced toxicity. That QSAR model was developed for the photoinduced toxicity of 16 PAHs to the higher plant Lemna gibba. The objective of this study was to apply the QSAR model developed for L. gibba to another organism. The organism chosen was the luminescent marine bacteria Vibriofischeri. Toxicity data used for the QSAR model were inhibition of luminescence and inhibition of growth of V. fischeri. Both short-term (15 min) and long-term (18 h) assays of toxicity were used. Light did not impact on PAH toxicity in the short-term assay, and thus the QSAR model did not correlate well with these data. Conversely, light greatly enhanced toxicity when the long-term assay was employed. The PMFs for the PAHs from the L. gibba QSAR showed a moderate correlation to bacterial toxicity in the long-term assay, whereas the PSFs showed only a weak correlation to toxicity. As was the case for L gibba, summing the PMF and the PSF resulted in a strong correlation to toxicity that had predictive value. Thus, a QSAR model derived for plants accurately described the toxicity of PAHs to a bacterial species. This indicates that the bipartite mechanism of PAH-photoinduced toxicity may be applicable to other organisms.
阳光可显著增强多环芳烃（PAHs）的毒性。光敏化反应（如单线态氧的生成）和光修饰反应（如PAHs光氧化为毒性更强的物质）都是PAHs光致毒性的途径。此前，已针对PAHs建立了定量构效关系（QSAR），表明光敏化因子（PSF）和光修饰因子（PMF）可相加组合以描述光致毒性。该QSAR模型是针对16种PAHs对高等植物浮萍（Lemna gibba）的光致毒性建立的。本研究的目的是将为浮萍建立的QSAR模型应用于另一种生物。所选生物为发光海洋细菌费氏弧菌（Vibrio fischeri）。用于QSAR模型的毒性数据是费氏弧菌发光抑制和生长抑制。使用了短期（15分钟）和长期（18小时）毒性试验。在短期试验中，光照对PAH毒性无影响，因此QSAR模型与这些数据的相关性不佳。相反，采用长期试验时，光照会极大增强毒性。来自浮萍QSAR的PAHs的PMF在长期试验中与细菌毒性呈中等相关性，而PSF与毒性仅呈弱相关性。与浮萍的情况一样，将PMF和PSF相加与具有预测价值的毒性呈强相关性。因此，为植物建立的QSAR模型准确描述了PAHs对一种细菌的毒性。这表明PAH光致毒性的二分机制可能适用于其他生物。
