Visnyk of Dnipropetrovsk University. Biology, medicine

47-51

Authors: I.I. Mykaylo, M.V. Kryvtsova, V.I. Nikolaichuk

The aim of our research was to conduct a monitoring study of nitrate content in plant products of Uzhgorod district and to accomplish comparative analysis of the survey results in different periods of crop ripening. Selection of vegetable samples was carried out in Uzhgorod district in the early spring and summer periods. Determination of the nitrate content was performed using an ion-selective method at the Chemical and Toxicological Department of the Regional State Veterinary Medicine Laboratory in the Transcarpathian region of Ukraine. Vegetables were tested for nitrate content using the ion-selective method with the laboratory ion meter AI-123. Core investigation samples were crushed and homogenized. A 10.0 g weight of the investigated product, which was prepared according to MIR № 5048-89, was placed in a flat-bottomed or a conical flask, which was then filled with 50 cm3 potassium alumens solution and shaken in a shaking-machine for 5 minutes and then transferred into a measuring glass. The nitrate weight fraction in milligrams per kilogram was obtained together with the weight concentration value of nitrate ions in solution. For our study we selected vegetables grown in both public and private gardens of Uzhgorod district, namely: common onions, radishes, garden parsley, cucumbers, tomatoes, bell peppers, white cabbages, carrots and table beets. 25 samples were selected for each type of vegetable. Nitrate content was determined in the early spring growing period (from February 9 to May 27, 2011) and in the summer growing period (from June 3 to September 28, 2011), because in these particular periods we recorded the most frequent cases of food poisoning from nitrates among the population of the region. A clear trend has been traced towards increasing the nitrate content in food plant production, at levels which exceed the maximum permissible concentration (MPC). The results of our research demonstrate that the nitrate content exceeded the maximum permissible concentration in 9 kinds of vegetables out of the 11 selected for the investigation, which composes 82% of total production. In particular, among the selected vegetables an excess of nitrate content, above MPC was recorded in 100% of cucumbers, 92% of carrots, 40% samples of green onions, 40% of radishes, 40% of tomatoes, 28% bell peppers, and 16% of early white cabbages. However, the most significant nitrate excess, which was more than double the MPC, was observed in 56% of cucumbers, 20% of tomatoes, 8% of radishes in the early spring period and 4% of tomatoes in the summer period. Consequently, it has been established that the consumption of early vegetable production contributes to the ingestion by humans of significant amounts of nitrates. The application of an agrochemical system based upon sound measurement of the nitrate content would allow us to solve the task of increasing soil fertility and to form a deficit-free and positive balance of biogenic elements and humus in the "soil – plant – fertilizer" system and develop a system of crop production which is balanced in its chemical composition and nutritional value. To sum up, detailed determination of the factors that lead to the accumulation of nitrates in vegetable crops and the development of methods to reduce nitrate concentrations in crop production require further investigation.

57-62

Authors: O.V. Melnyk, O.P. Kornijchuk, O.I. Pershyn, Z.D. Vorobets

A significant role in the development and course of reactive arthritis (ReA) is played by T-lymphocytes as their development and systemic manifestations are based on immunological mechanisms. Additionally, the pathogenesis of many diseases is linked to changes in the structure and function of ion-transporting systems. Therefore, the aim of the study was to find out the kinetic properties of ATP-hydrolysis reaction involving Na+,K+-ATPase of peripheral blood lymphocytes of healthy individuals and patients with ReA. We used the current methodological approaches to the study of ATPase activity in saponin permeabilized cells. We conducted an analysis of the kinetic properties of ouabainsensitive Na+,K+-ATPase activity of saponin-perforated peripheral blood lymphocytes of healthy donors and patients with rheumatoid arthritis (RеA). We found out that in peripheral blood lymphocytes of patients with RеA primary active transport of Na+, K+ ions is slower and less intensive, though characterised by the same capacity, as in healthy donors. The affinity constant for ATP in peripheral blood lymphocytes in patients with RеA is greater by 2.9 times than its value in comparison with healthy donors. We established that in conditions of rheumatic pathology in immunocompetent cells, inhibition of Na+,K+-ATPase activity is not caused by reduction of speed of enzyme work, but by increase of affinity of ouabainsensitive Na+,K+-ATPase to ATP. At the same time, the Mg2+-binding center of Na+,K+-ATPase in patients with RеA is endogenous. We also found that affinity Na+,K+-ATPase to the ions K+ in peripheral blood lymphocytes of healthy donors is 2.4 times higher than in patients with RеA. We observed that Na+,K+-ATPase of peripheral blood lymphocytes of patients with RеA retains its endogenous receptor properties – sensitivity to ouabain does not change. It is assumed that under conditions of rheumatic pathology the impact on the Na+,K+-ATPase structure occurs both externally and on the cytoplasmic membrane surface. The above experimental data can be used for further clarification of the membrane mechanisms of ion exchange in immunocompetent cells of patients suffering from autoimmune diseases.

71-75

Authors: N.P. Kilochytska

From the epidemiological viewpoint the greatest threat to human health is represented by female mosquitoes in the hematophagous stage. Contact with these bloodsucking insects occurs most frequently in their places of diurnal concentration. The main daytime habitats of mosquitoes in urban areas are recreational areas, especially near water – forests, parks, botanical gardens, cemeteries, green zones in residential areas, residential buildings and buildings with livestock, basements and cellars. In the context of global warming and extreme high summer temperatures a tendency has been observed for mosquitoes to make increasing use of residential premises and outbuildings as a daytime habitat. In the Solomianskyi district of Kiev a six-year monitoring programme of mosquitoes’ diurnal habitat distribution was conducted. It showed that the majority of female mosquitoes which attacked humans (60%) were concentrated in areas of recreation and outdoors in residential areas. Simultaneously a significant number of mosquitoes was found to use as their daytime habitat places where they were in close proximity to humans – in domestic outbuildings (sheds under various uses), basements and cellars. The lion’s share of these mosquitoes was represented by Anopheles maculipennis (25%) and Culex pipiens (7,6%). At the same time a significant number of representatives of the genera Ochlerotatus (O. cantans, O. sticticus, O. cataphylla) and Aedes (Ae. v. vexans) were also recorded using residential premises as their daytime habitat on a scale which had not been previously observed for these species of mosquito. It is possible that female mosquitoes fly into livestock buildings at twilight because they are attracted by electric light and ammonia vapors. However, these factors are almost absent in basements and cellars. It remains to be noted that mosquitoes use basements and cellars as a daytime habitat at periods of hightemperatures and low humidity in the city. To test this assumption the distribution of mosquitoes was analysed during the warm season in 2010 in Solomyanskyi district with measurement of temperature at the locations of collection. It turned out that the air temperature in the sheds was 2–4 °C lower than outside in the shade, in the basements lower by 4–11 °C, and in the cellars lower by 4–12 °C. Comparison of the temperature in the daytime habitats and number of mosquitoes found there showed a direct relation between the outdoor temperature and the number of mosquitoes in the daytime habitat on the premises. The data indicate that there is a tendency for the number of synanthropic blood-sucking mosquito species to increase owing to the occupation of domestic premises as a daytime habitat by those species of mosquitoes for which this phenomenon was not typical earlier. If global warming and the current trend to increase in summer temperatures persist, this can cause a deterioration of the epidemiological situation in the megalopolis.