Determination of photosynthetic and enzymatic biomarkers sensitivity used to evaluate toxic effects of copper and fludioxonil in alga Scenedesmus obliquus.
Modulated PAM fluorometry and Plant Efficiency Analyser methods were used to investigate photosynthetic fluorescence parameters of alga Scenedesmus obliquus exposed to inhibitory effect of fungicides copper sulphate and fludioxonil (N-(4-nitrophenyl)-N'-propyl-uree). The change of those parameters were studied when alga S. obliquus have been exposed during 48 h to different concentrations of fungicides (1, 2 and 3 mgl(-1)). Under the same condition, enzymatic activities of catalase, ascorbate peroxidase, glutathione reductase and glutathione S-transferase were investigated to evaluate antioxidative response to fungicides effects. The change of sensitivity of those parameters was dependent to the mode of fungicide action, their concentration and time of exposure. For copper effects, the most indicative photosynthetic biomarkers were parameters Q(N) as non-photochemical fluorescence quenching, Q(Emax) as the proton induced fluorescence quenching and ABS/RC as the antenna size per photosystem II reaction center. Copper induced oxidative stress was indicated by increased activity of catalase serving as the most sensitive and valuable enzymatic biomarker. On the other hand, fludioxonil effect on photosynthetic parameters was very negligible and consequently not very useful as biomarkers. However, fludioxonil induced strong antioxidative activities associated with cytosol enzymes, as we found for catalase, ascorbate peroxidase and glutathione S-transferase activities. By obtained results, we may suggest for the activation of those enzymes to be sensitive and valuable biomarkers of oxidative stress induced by fludioxonil. Determination of biomarkers sensitivity may offer advantages in providing real criteria to use them for ecotoxicological diagnostic studies.
Département de Chimie et de Biochimie, Centre TOXEN, Université du Québec à Montréal, CP 8888, Succursale Centre-Ville, Montréal, Québec, Canada H3C 3P8.
David
D
Dewez
Laure
L
Geoffroy
Guy
G
Vernet
Radovan
R
Popovic
D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D019327:Copper Sulfate / Q000633:toxicity*; D004149:Dioxoles / Q000633:toxicity*; D005434:Flow Cytometry; D005470:Fluorometry; D005659:Fungicides, Industrial / Q000633:toxicity*; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects*; D011758:Pyrroles / Q000633:toxicity*; D044444:Scenedesmus / Q000187:drug effects* / Q000201:enzymology*
D004149:Dioxoles; D005659:Fungicides, Industrial; D011758:Pyrroles; D002734:Chlorophyll; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; C108339:fludioxonil; D019327:Copper Sulfate; D000077194:Chlorophyll A