engleski

The possible influence of some physiological parameters on EROD-activity data valuation

Biomonitoring using molecular biomarkers in fish is very important in environmental risk assesment. In order to choose the suitable test organism and to interpret the results after exposure to environmental conditions, it is necessary to know basal biochemical and physiological parameters of the test organism. Unspecific hydroxilase is an enzyme that belongs to the family of cytochrome P-450 dependent monooxygenases. This enzyme is higly inducible if the organism is exposed to contaminants belonging to the group of polyaromatic hydrocarbons, biphenyls, dibenzodioxines or dibenzofurans. Previous researches have confirmed that activity of this enzyme (measured as EROD-activity) is a reliable indicator of that sort of pollution and contamination of salt and fresh waters. On the other hand, the facts related to the variability of this biomarker depending on species, locality and other biochemical and physiological factors have remained unexplained. Three freshwater fish species - prussian carp (Carassius auratus gibelio), common carp (Cyprinus carpio) and browh bullhead (Ictalurus nebulosus) from three different locations - Grudnjak and Siščani fishponds and river Drava were investigated as test organisms in this work. One group of experimental animals was treated with 3-methylcholantrene (3-MC) as model pollutant (inducer), while the second group was simultaneously investigated without being treated. During the research, twenty different parameters were measured: weight of fish, hepato-somatic index, activity of unspecific hydroxilase with 7-ethoxyresorufin as supstrate (EROD), activity of acetylcholine-esterase in muscle, liver and brain, amount of reduced glutathione in muscle, liver and brain, activity of aspartate-transaminase in liver, activity of alanine-transaminase in liver, activity of lactate-dehydrogenase in muscle and liver, and amount of glucose in liver. The research has shown that it is possible to realize the level of relations between measured factors and ascertain their representation in variance of response to the exposure to pollutant using sophisticated statistical methods, such as cluster analysis, principal component analysis and diskriminant analysis. Besides that, on the basis of the results obtained in this research, it is possible to optimize monitoring the exposure to pollutant of 3-methylcholantrene type using the acitvity of unspecific hydroxilase as molecular biomarker of exposure.

molecular biomarkers; biomonitoring; cytochrome P-450; EROD activity

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