Visnyk of Dnipropetrovsk University. Biology, ecology

3-8

Authors: O. Maslovska, S. Hnatush

Desulfuromonas acetoxidans obtains energy for growth by the anaerobic oxidation of organic compounds with the carbon dioxide formation. It was found that ferrum and manganese are used as terminal electron acceptors in the processes of anaerobic respiration, such as dissimilative Fe3+- and Mn4+-reduction, carried out by these bacteria (Lovely, 1991). D. acetoxidans ІМV B-7384 can be used as anode biocatalyst in microbial fuel cell with high electron recovery through acetate oxidation to the electric current as a result of electron transfer to the anode or 3d-type transition metals, such as ferrum and manganese, in the process of their reduction. Investigation of biochemical changes of D. acetoxidans ІМV B-7384 under the influence of Fe (III) compounds is important for optimization of the process of bacterial electricity generation. ATP-hydrolase is located in cytoplasmic membrane, and its subunits are exposed to both the cytoplasm and the external environment. Therefore, the changes of that enzyme activity can be used as an indicator of various stress exposure. Presence of ferric iron ions in the bacterial growth medium could catalyze generation of organic reactive oxygen species, such as peroxyl (ROO-) and alkoxyl (RO-) radicals. Lipid peroxidation is one of the main reasons of cell damage and it’s following death under the influence of reactive oxygen metabolites. It is known that lipid peroxidation and membrane transport processes are somehow interrelated, but mechanisms of such interaction are still unidentified. In our previous researche we have shown the influence of ferric (III) citrate on the intensity of lipid peroxidation of D. аcetoxidans ІМV В-7384. Significant increase of the content of lipid peroxidation products (lipid hydroperoxides, conjugated dienes and malondialdehyde) in bacterial cells has been observed under the addition of ferric (III) citrate into the cultural medium. The increase of the concentration of lipid peroxidation products in bacterial cells confirms free radical mechanism of oxidation of polyunsaturated fatty acids. Thus, for fulfiling complete analyses of cell response against oxidative stress it was reasonable to investigate the influence of ferric (III) citrate on specific ATP-hydrolase activity, Na+, K+-ATP-hydrolase activity and Mg2+-ATP-hydrolase activity of D. acetoxidans ІМV В-7384. Bacteria were cultivated in the modified Postgaite C medium during four days under the anaerobic conditions and temperature +27°С with addition from 10 to 20 mM of ferric (III) citrate into the growth medium. Control samples didn’t contain investigated metal salt. Chosen concentrations of metal salt caused inhibition of bacterial growth by 20–50%. Activities of ATP-hydrolases were investigated as described. It was shown, that specific ATP-hydrolase activity of D. acetoxidans ІМV В-7384 is changing in dependance on duration of ferric (III) citrate exposure and concentration of the metal salt. Addition of the ferric (III) citrate in relatively low concentrations (10–12 mM) causes increasing of specific ATP-hydrolase activity of D. acetoxidans IMV B-7384 in comparison with control. Activity of investigated enzymes was inhibited under the increasing of metal salt concentration in bacterial growth medium. Increase of duration of D. acetoxidans IMV B-7384 cultivation causes decrease of ATP-hydrolase activity. Addition of ferric (III) citrate causes simultaneous increasing of Na+, K+-ATP-hydrolase activity and inhibition of Mg2+-ATP-hydrolase activity during four days of bacterial cultivation.

15-19

Authors: R. Kononenko

The state of world stocks of sturgeons is on the edge of catastrophe. These species are either extinct or under threat of extinction under human impacts. At the same time, there are enterprises, fish hatcheries, which deal with restoration and replenishment of natural stocks with of endangered fish species. One of such hatcheries is the sturgeon hatchery “Lebyazhy” (Astrakhan region, Russian Federation). The aim of the study was an analysis of piscicultural-biological features of the Russian sturgeon brood fish. During the study, which was conducted in April–May 2011, 34 Russian sturgeon females were used in two rounds, 17 individuals each. For stimulating gametes maturation, the Derzhavin’s physiological method was used. Caviar was obtained by stripping the eggs under strict hygienic and sanitary norms. Eggs fertilization with the semi-dry method used the male milt that bought at the “Raskat” LLC. Egg stickiness elimination was performed with the aid of talc and apparatuses for the egg stickiness elimination. Eggs incubation was performed in the “Osetr” apparatuses until yolk-sac larvae hatching. The domesticated fish were subjected to bonitation for determining their readiness for spawning. As a result of this bonitation, the brood fish were separated into two groups: first round of rearing works: females with mean weight of 34.8 kg and age of 9 years; second round: females with mean weight of 32.3 kg and the same age. Among injected females of the first round, 100% positive reaction for the stimulating injection was observed, but 95% – among females of the second round. Maturation time of females of both rounds varied from 25 to 30 hours. The maturation state of gametes of sturgeon females or males was determined based on samples obtained. 90.2 kg of eggs were obtained from females of the first round. At the same time, the maximum quantity was observed in the female of 50.5 kg – 9.2 kg of caviar, and the least quantity was obtained from the 27.8 kg female – 2.8 kg. On average, 5.3 kg of eggs were obtained per one female of the first round. The obtained quantity of eggs in one gram did not exceed 48 eggs that are considered to be within normal limits. 79.8 kg of eggs were obtained from females of the second round of rearing works that is 10.4 kg less in comparison with the results of the first round. On average, 5.0 kg of eggs were obtained from one female that is related to less mature fish used in the second tour. At the same time, the maximum quantity of eggs, 7.9 kg, was obtained from a 32.5 kg female, while the minimum quantity, 2.6 kg, from a 20.7 kg female. The obtained quantity of eggs in one gram did not exceed 44 eggs. Mean working fecundity of females of the first round was 198.2 thousand eggs, while it was somewhat less in the second round – 184.6 thousand eggs that did not exceed the normative values.

28-32

Authors: S.N. Kabuzenko, A.V. Omel’chenko, L.М. Mykhalska, V.V. Schwartau

The goal of this work is studying the accumulation and distribution of Na+ and K+ in maize hybrids of different salt tolerance under conditions of the chloride salinity. The new corn hybrid Veselka MV (salt-tolerant) and Odessa 375 MB (not salt-tolerant) were studied. The plants grown in salt-free chernozem soil are control. In the experiment, sodium chloride was dissolved in the irrigation water to form the salinity of test soils up to concentrations of 0.25, 0.5, 0.75, and 1.0% of ovendry weight. Soil moisture in the pots was maintained at 60% of the full field water capacity, the air temperature was +25…+27 °C, and the light – 10 klux. Plant samples were dried in the oven under 70°C. Then, the average sample of 10 specimens was thoroughly levigated in the porcelain pounder and dispersed in distilled water at 100°C. The ions were extracted, and the extracts were centrifuged for 20 min at 3000 rpm. The ions content in the cell sap was analysed. Plant samples (1 g) were incubated 10 min in chloroform, dried carefully with filter paper, and then the cell sap was squeezed. 1 ml of clear top layer of the cell sap was dissolved in 10 ml of distilled water. Ions content was determined by the atomic absorption spectrophotometer ("Karl Zeiss", Germany). Salt-tolerant maize hybrid Veselka MW (14 days age) is characterized by an increased content of Na+ in the root tissues in comparison with the above-ground parts. In Odessa 375 MB hybrid this regularity is less pronounced. With the increase of sodium chloride concentration in the soil the content of Na+ in the aerial parts of plants rises. That may be connected with the reduced role of a root barrier. The salt-tolerant hybrid has a higher content of Na+ in the roots as compared to the above-ground parts. The content of K+ was higher in the above-ground parts, which is more pronounced in the salt-tolerant hybrid Veselka MB. The decrease of K+ in cell sap of the root under saline conditions was most pronounced in the salt-sensitive hybrid Odessa 375 MB. The salt-tolerant hybrid Veselka MB is characterized by accumulation of Na+ mainly in the roots, but a higher content of K+ in the aerial part of the plant. For salt-tolerant hybrids are characterized by a higher ratio of K+ / Na+ in the above-ground parts of plants as compared to the not salt-tolerant hybrid.

38-42

Authors: D.Y. Reshetniak, V.V. Brygadyrenko

Development of the laboratory breeding technology of insects that damage agricultural crops can help in the pest control. Harpalus rufipes (De Geer, 1774) were fed by the following types of products: fresh frozen chicken and pork, cooked sausage "Doctor", cheese "Russian", boiled wheat and buckwheat. In the experiment, 56 adult specimens were kept individually in plastic containers during five days. In the same conditions 8 control test products were placed to determine the percentage of its mass loss due to desiccation. Keeping in a laboratory and feeding of H. rufipes (De Geer) by common human food is possible. Throughout the experiment, there were considerable variations in the consumption of food between individuals. Specimens of an average weight of 148.2 ± 45.6 mg consumed daily 71.4 ± 99.4 mg of fresh-frozen chicken and 77.2 ± 112.8 mg of the pork meat (48.1% and 52.1% of the body weight, respectively). Cheese and sausage were consumed in approximately the same amounts (73.1 ± 81.3 and 44.9 ± 66.0 mg daily, or 49.3% and 30.3% of the body weight, respectively). Low protein crop ration (wheat and buckwheat) provided the increase of the food intake (103.5 ± 108.5 and 79.8 ± 91.5 mg or 69.9% and 53.9% of the body weight, respectively). Chicken, pork meat and sausage contributed the weight gain, which amounts to about 0.43–0.82 mg (0.29–0.56% of initial body weight). A significant increase in body weight was observed for specimens feed by cheese (the weight gain was 3.14 ± 18.3 mg, 2.12%), by wheat (8.71 ± 21.33 mg, 5.87%), and buckwheat (2.73 ± 13.75 mg, 1.84% of the body weight). Starving individuals of H. rufipes that had an access to drinking water lost 2.6 ± 3.6 mg of the wet weight daily (1.76% of the body weight). That low rate of basal metabolism ensures the species survival during unfavourable parts of the seasons (summer drought, long autumn rains, etc.). Thus, the changes of body weights in imagoes of similar diets are evaluated. The sustainable keeping of H. rufipes (De Geer) culture in a laboratory needs the alternation of used food. That problem should be studied in details.

51-57

Authors: A.E. Pakhomov, O.M. Kunakh, A.V. Zhukov, Y.A. Baliuk

Study results of the spatial organisation of urbozem mesofauna are presented. We used the OMI-analysis methods. Field research was made in June, 1st, 2011 in the Botanical Garden of Dnipropetrovsk National University (DNU) (earlier – the territory of Y. Gagarin park, Dnipropetrovsk). The studied plot is situated at a distance of 220 m from the Building 1 of DNU and at a distance of 60 m from Y. Gagarin Avenue (the Southeast direction). The plot consists of 15 transects directed in a perpendicular manner in relation to the Avenue. Each transect is made of seven sample points. The distance between points is 2 m. The coordinates of lower left point have been taken as (0; 0). The plot represents artificial forest-park planting. The vegetation has typically wood mesotrophic mesophilic character (93.3% – silvants, 90.0% – mesotrophes, 81.7% – mesophiles). In each point the soil mesofauna was studied; temperature, electrical conductivity and soil penetration resistance, dead leaves layer and herbage height were measured. Soil-zoological test area had a size of 25 × 25 cm. We found that earthworms are numerous and saprohages are presented by 5 species. The Aporrectodea caliginosa trapezoides (Duges, 1828) is a dominant species. Along with that species an ecological group of endogeic earthworms is presented by A. rosea rosea (Savigny, 1826) and Octolasion lacteum (Oerley, 1885). An ecological diversity of earthworms is supplemented by epigeic Lumbricus rubellus (Hoffmeister, 1843) and anecic Octodrilus transpadanus (Rosa, 1884). The hygromorphs of earthworms range from ultrahygrophiles to mesophiles. The coenomorphic spectrum of earthworms is also rather wide and presented by “pratants”, “stepants”, “palludants” and “silvants”. The complex of earthworms in studied area is taxonomically and ecologically diverse. The ecological structure of soil animal community is presented by such dominant ecological groups as saprohages, pratants, hygrophiles, mesotrophocoenomorphs, and endogeic topomorphs. The measured soil characteristics have been shown to play an important role in structuring an ecological niche of mesopedobionts community. The basic trends in structure transformation of the soil mesofauna community are ecotone effect and edaphic properties determined by a vegetation cover.