M. Augustyniak

Does the grasshopper Chorthippus brunneus adapt to metal polluted habitats? A study of glutathione-dependent enzymes in grasshopper nymphs

Glutathione contents and activity of glutathione‐dependent enzymes in the body of insects inhabiting polluted areas depend on toxin kind, concentration and exposure time. Enzymatic response may be modified by gender, age, developmental stage and state of nutrition. Also, chronic exposure to metals in the environment may cause the selection of individuals resistant to some environmental toxins. To assess the degree of adaptation of Chorthippus brunneus to metal‐polluted habitats, we measured glutathione contents and the activity of selected glutathione‐dependent enzymes in the offspring of aging mothers which differed in time and intensity of exposure to metals in their habitats. We tested whether differences represent temporal shifts in tolerance range or were genetically preserved and inherited by future generations. We investigated insects from three populations. Two live in heavily metal‐burdened areas, exposed to metals for 170 (Szopienice) or 50 years (Olkusz) and the third inhabits an unpolluted reference site (Pilica). The most important findings were age‐by‐site interactions for all biochemical analyses. Nymphs from Szopienice had lower glutathione contents and lower glutathione‐dependent enzyme activity in comparison with nymphs from the reference site. This was especially distinct in nymphs hatched from eggs laid by young females. The offspring of aging females from Olkusz, in terms of glutathione contents and glutathione reductase activities, revealed similar patterns to those from the reference site. For the remaining parameters, enzyme activity patterns in nymphs from Olkusz were similar to those of nymphs from Szopienice.

DNA damage in grasshopper Chorthippus brunneus (Orthoptera) hatchlings following paraquat exposure

Comet assay was applied to study genotoxic damage induced by paraquat (PQ) in brain cells of Chorthippus brunneus (Insecta: Orthoptera) hatchlings. Percentage of the comet fluorescence in the tail (TDNA), length of the comet tail (TL) and Olive tail moment (OTM) were used for quantitative assessment of the DNA damage. Multiple regression analysis supplemented standard statistical elaboration of the results. Increasing PQ concentrations applied either directly to the brain cells suspension (10, 50, and 250 μM PQ final concentration--in vitro protocol) or indirectly (50, 250, and 1250 μM PQ final concentration--in vivo protocol) provoked significant increase of oxidative damage to DNA (higher median TDNA and OTM values). The damage increased with time of exposure (0, 5, 15, and 30 min) following in vitro application, but decreased in longer interval (3 vs 24 h) after in vivo administration of paraquat. On contrary, median TL values did not correlate with paraquat concentration irrespectively of the exposure protocol. Possible reason of this discrepancy in light of paraquat toxicity is discussed.

Validation of Selected Biomarkers in Invertebrates from the Polluted Silesian Region

A number of technological changes has led to an improvement in the condition of the heavily polluted region of Upper Silesia. Nevertheless, organisms living in this area are exposed to a combination of toxic chemicals at levels exceeding those permissible by the environmental law. In this report some research activities from our laboratory, concentrated on application of biomonitoring and biomarkers in terrestrial invertebrates from this region to monitoring programmes, are presented. Their advantages, validation and constraints are discussed. Non-specific biomarkers, such as metabolism rates of intact animals and general indices of energetic processes - adenine nucleotide concentrations, and the adenylate energy charge (AEC) - were studied in various groups of insects and spiders. These biomarkers are also affected by many non-chemical factors. It is difficult to separate toxic effects from natural factors since time-related assays with the same organisms often produced significantly different results.