Abundance of adult ticks (Acari: Ixodidae) in the Chernobyl nuclear power plant exclusion zone.

The Chernobyl nuclear disaster resulted in contamination of vast areas in Europe. To date, there is little knowledge about the effects of radioactive contamination on tick species. We sampled ticks from vegetation and large-sized wild mammals belonging to orders Carnivora and Artiodactyla at sites with 0.76, 1.91, and 4.50 mSv/hr ionizing radiation background values in the Polesky State Radio-Ecological Reserve of the Chernobyl nuclear disaster zone in spring 2010. Altogether, 122 questing ticks were collected from vegetation. Among collected ticks, Dermacentor reticulatus (Fabricius) was, by far, the most abundant species (99.2%), followed by Ixodes ricnus (L.) (0.8%), which was collected only at the 0.76 mSv/hr site. The average sex ratio female∶male was 2.9∶1.0. In parallel with the present study, we examined 3 Sus scrofa (L.), 2 Nyctereutes procyonoides (Gray), and 1 Alces alces (L.) at the 4.50 mSv/hr site; 96 D. reticulatus ticks were found on 2 N. procyonoides specimens. The mean density and the intensity of infestation were 16 ticks per animal and 48 ticks per infested animal, respectively. Future investigations are warranted to further characterize the role of various tick vectors, vertebrate reservoirs, and diversity of tick-borne pathogens in the Chernobyl exclusion zone.

[Peculiarities of amino acids transformation in brain under conditions of acute hypoxic hypoxia]. / Osobennosti prevrashchenii aminokislot v mozge v usloviiakh ostroi gipoksicheskoi gipoksii.

Acute 15, 30 and 60-minute hypoxia induced in a rabbit placed in the altitude chamber at the atmospheric pressure of 260 mm Hg was an experimental model for a hypoxic state. An increase in the amount of aspartate in the brain under conditions of 15-minute hypoxia and its decrease with prolongation of the hypoxia period up to 1 h may be explained by different mechanisms of amino acids metabolic transformations under these conditions. Changes in the content of aspartate are adequate to these in the activity of aspartate aminotransferase. An increase in the glutamate content in the brain the 30- and 60-minute hypoxic effect is accompanied by a rise of the activity in the glutamine synthesis enzyme (glutamine synthetase). Dynamics of the aspartate quantitative changes in the brain in different periods of acute oxygen deficiency affecting metabolic shifts in amino acids metabolism may serve as an index of the hypoxic effect gravity.