This study is aimed at analyzing the total mercury in the tissues of mammals adapted to a semiaquatic or subterranean lifestyle and at analyzing the possible role of their antioxidant system in heavy...

The Northern bat, Eptesicus nilssonii, is the most common species among northern chiropteran populations. The species is noted for its long hibernation period with low mortality rate. We investigated the morphology of E. nilssonii blood cells during hibernation, hematological parameters including hemoglobin level, red blood cell (RBC) count, total white blood cell (WBC) count, and differential WBC count. The study revealed changes of several hematological parameters in hibernating bats, with some variation during the hibernation season. Hibernating E. nilssonii were found to have a low total WBC count similar to other hibernators; no significant variation in WBC count was noted during hibernation. Differential leukocyte count showed a significant reduction in total monocytes in winter (in the middle of the hibernation period). Total lymphocyte, band neutrophil, and basophil counts increased in spring (termination of the hibernation period).

We have studied the age-related features of circadian rhythms of superoxide dismutase (SOD) and catalase activity in the liver of rats under conditions of light deprivation. In standard light conditions (LD), significant daily fluctuations in SOD activity with a maximum at 7:00 a.m. were detected only in young animals (1.5 months) while catalase activity was observed in both young animals (1.5 months) and adults (7.5 months) with peak at 4:00 a.m. The daily dynamics of total and specific activity of SOD and catalase in the liver of young and adult rats differed, depending on the period of ontogeny in which the impact of light deprivation had begun. When females after giving birth and their offspring were moved to darkness (group LD/DD), the circadian rhythms of SOD and catalase activities were found in the young rats and were absent in adult rats. However, circadian rhythms of the antioxidant enzymes (AOE) activities were inherent only in adult rats when light deprivation impacted on pregnant females (group DD/DD). Changes in circadian rhythms under light deprivation were characterized either by a phase shift of the enzymes activity (in LD/DD group) or by a violation of their development in ontogeny (in DD/DD group). With aging a significant decrease of catalase activity was compensated by an increase in the amplitude of circadian rhythms of this enzyme activity in animals of all groups. The presence of an ultradian rhythm in the general circadian cycle characterized by a second peak with a smaller amplitude and shorter period can be considered a distinctive feature of daily fluctuations in AOЕ activity in young rats in LD and LD/DD groups.