Visnyk of Dnipropetrovsk University. Biology, ecology

59-63

Authors: K. V. Derkach, O. E. Abraimova, T. M. Satarova, O. A. Molitva, V. S. Kalugina, M. G. Panasenko, S. S. Pechorna

In connection with the necessity of bringing elite maize inbreds of the Lancaster germplasm group, which have potential for cultivation in Ukraine, into the system of genetic tranformation, the aim of this investigation is to identify the ability of maize inbreds of this group to regenerate by direct organogenesis and to determine the optimal mineral basis for their nutritional environment using segments of the node area of shoots. As explantats we used sterile 4-day old seedlings of 4 maize inbreds of Lancaster germplasm and model inbred Chi31 exotic germplasm. The seedlings were obtained by germination of sterile seeds in Petri dishes between two layers of moist sterile filter paper at a temperature of 27 ºC in dark conditions. A single 1 cm long segment was cut from each from each seedling, running from 0.5 cm before the node to 0.5 cm after the node. A cut was made in each segment of the node in order to create a wounded surface. Explantats were planted in a nutrient environment with mineral bases of MS or N6, modified by the addition of 10 mg/l silver nitrate, 100 mg/l casein hydrolyzate, 690 mg/l L-proline, 30 g/l sucrose, 1.0 mg/l 2,4-dychlorphenoksiacetic acid and 0,1 mg/l abscisic acid. Cultivation was carried out at 25–27 ºC in the light. Direct hemogenesis in this environment on the 14th day of cultivation in vitro reached 100% for each line. This meant that all researched lines of Lancaster germplasm and the model line showed a high capacity for direct regeneration through direct hemogenesis, which does not depend on the composition of the mineral content of their nutritional environment. Callus formation was observed in all genotypes on the 14th day of cultivation in vitro and the extent of its formation increased during the following month of cultivation. The callus formation was observed only at the site of the wounded surface. The calluses were transparent. Although green areas appeared in these calluses, they were nonembryogenic and did not lead to regeneration. All explantats were transplanted into fresh nutrient media with simultaneous removal of germinated shoots on the 14th day of cultivation. Regeneration on the 45th day of cultivation took place by direct hemogenesis (formation of shoot or leafy structures) or direct hemoryzhogenesis (formation seedlings which had both shoot and root). Formation of ryzhogenic calli was observed in most inbreds. The frequency of regeneration of shoots and leaf structures was characterized by a tendency to increase indicators in the culture environment with mineral basis N6, and the frequency of regeneration of shoots was significantly marked using a medium with mineral basis MS. However, regeneration on the 45th day took place at a much lower rate than on the 14th day of cultivation, which must be taken into account when a system of genetic transformation systems using nodal segments of seedling shoots is being developed. Thus, using nodal sections of 4-day old seedling shoots of maize inbreds of Lancaster germplasm and model inbred Chi31, we can obtain viable seedlings for use in biological systems of agrobacterial transformation. We can recommend two variants of provoking regeneration by direct organogenesis in vitro for application in genetic transformation. The first variant suggests for all studied genotypes 100% induction on the 14th day of in vitro cultivation of direct organogenesis by hemogenesis and this requires further rooting of obtained shoots before planting into soil. Both variants of the nutrient environments of cultivation proposed us can be used. The second variant involves low frequency of regeneration by direct hemoryzhogenesis in a limited number of genotypes, but excludes the rooting stage. The cultivation environment with the mineral basis MS is recommended for this variant. The choice of either variant for obtaining direct regeneration depends on the particularity and aim of the research.

70-75

Authors: D. V. Chernetchenko, M. P. Motsnyj, N. P. Botsva, О. V. Elina, M. M. Milykh

A hardware-software complex automated system of recording bioelectrical potentials, which is based on a USB-device with subsequent processing of signals with PC was developed in this work. We proposed a universal scheme of registration of bioelectrical potentials, which allows one to detect the reaction of biological objects to different stimuli, such as cold, heat, photo- and electrical stimulation, and to different combinations of these stimuli (Motsnyj et al., 2004). They could be applied for deeper understanding of the biological mechanisms of generation of electrical potentials in cells and discovering the accommodation processes of organisms as a whole to these stimuli. The system for registration of bioelectrical potentials consists of hardware and software parts. The software part consists of the client and server sides, which transmit experimental data to the network. The client-side software renders a quantitative analysis and stores the results in a database. An integrated system of registration and biometrical processing was applied for analysis of the electrical responses of maize leaves to heat stimuli. The dynamics of these potentials were studied and a quantitative analysis of the potential level stabilization was made. We found that amplitude relation of responses to the initial response increased and stabilized at the level of 130%. Mathematical models of the plant cell for discovering intracellular mechanisms of biopotentials registration were developed. As a result of modeling, we found that the electrical response of the cells is based on selective conductance of the cell membrane for Н+ and K+ ions. By this way, we show the biophysical relation of plant potentials to intracellular biophysical mechanisms.

83-88

Authors: M. Tkachenko

We conducted a comparative analysis of the absolute and relative fecundity of round goby (Neogobius melanostomus (Pallas, 1984)) females in the Kakhovskyy Reservoir and the Azov Sea. We analysed the indicators of salinity, pH and oxygen levels in the waterbodies investigated. We determined the dependence of fertility of round gobies on body weight, length and age. This article presents the results of a comparative analysis with the works of other authors, including the results of a similar study conducted 40-years ago. We conducted cameral processing of the results by standard methodology. We counted the oocytes at varying stages of maturity. All oocytes were grouped by their diameter. We visually identified four groups of oocytes: 1700–2500 mkm – the large, mature oocytes (ІV stage of maturity); 400–1200 mkm – light yellow oocytes, which are ripening (ІІІ stage); 100–300 mkm (ІІ stage) whitish eggs, and the smallest (I stage) – up to 100 mkm. Stages II–IV were subjected to statistical processing. The differences between the indicators of fertility of fishes from saltwater and freshwater waterbodies show an increase in the relative and the absolute fecundity of fishes from the sea (saltwater) and decrease in the fecundity of the fishes in freshwater. The correlation analysis between the waterbodies and the length of the fishes showed 0.81 at the Kahovskyy Reservoir and 0.62 in the Azov Sea. The correlation analysis between the same waterbodies and the weight of the fishes was 0.63 and 0.74 respectively. This could indicate that conditions for the fishes’ existence were more favourable in the sea. The comparison analysis between our data and the 40-year old data for the Azov Sea depending on length and weight show a significant increase in oocyte numbers. This increase was noted for all size groups of fish. Nevertheless, the greatest differences were between fish in the Azov Sea (all data) and those in the Kahovskyy Reservoir. These results should be studied in the context of the nutrition spectrum and calorific objects of the round goby in these water bodies. It would be interesting to analyse data on gobies of the Azov Sea according to gradation in salinity levels.

95-100

Authors: S. O. Kochubey

We investigated the impact of the level of stochastic excitation of synaptic signals from pyramidal neurons on the generation of oscillations inside the interneuronal networks of the hippocampus with shunting GABAergic synapses. We used a modification of a mathematical model of the interneuronal networks (I. Vida, M. Bartos and P. Jonas, 2006) together with a model of external synaptic signalling with a Poisson distribution of time interval between events. We demonstrated that a completely synchronized synaptic signal when every interneuron in the network was impacted by an electric current with the same amplitude and frequency caused oscillations with a high level of synchronization (k > 0,9) in the network. The increase of synaptic signal frequency led to the respective increasing of oscillation frequency in the network. We demonstrated that a gradual increase of stochastic synaptic current from 0.001 to 0.200 causes reduction of synchronisation of oscillations in the interneuronal network from 0.89 to 0.11 with an equal signal frequency of 6 Hz. The frequency of oscillations in the interneuronal network also decreased from 55.6 to 35.7 Hz respectively for the levels of stochastisity 0.001 to 0.200 and the frequency of excitation of 58 Hz. Decrease of frequency and synchronization of oscillations in the network could be explained by the the inability of shunting GABAergic synapses to synchronize the work of separate interneurons when there is significant increase in stochastic external excitation. Besides this, we demonstrated the existence of a range of frequencies of the incoming signal of 30–40 Hz in the network, of which a significant increase of synchronisation of oscillations in the network takes place regardless of the stages of external stochastic excitation.

105-112

Authors: T. Shevtsova, E. Garkava, J. Brindza, T. Brjuzgina, V. Groza

Pollen has various effects on the human body. In order to study and compare the biological activity of the mature pollen grains of Betula verrucosa Ehrh. we investigated the protein-lipid composition and total antioxidant activity (TAA) of 10 samples from different habitats in the territory of Ukraine and the Slovak Republic. The collection sites are near highways and apartment blocks, as well as a nature reserve, forest and botanical garden. The protein content was determined by the Kjeldahl method. A chromatographic analysis of fatty acids from lipids was performed using a “Cvet 500” gas chromatograph, equipped with a flame-ionization detector in the isothermal mode. The bioactivity of aqueous, ethanol and methanol extracts of pollen grains was evaluated by the DPPH free radical scavenging method (2,2-diphenyl-1-picrylhydrazyl) by means spectrophotometry in vitro. The protein content of the pollen of B. verrucosa ranged from 17.9% to 25.6%, depending on the habitat. Unsaturated fatty acids were found in higher amounts than saturated fatty acids. The profile of fatty acids indicates a higher content of palmitic (33.9%), oleic (29.5%) and linoleic (27.8%) acids and a low content of arachidonic (0.4%) and pentadecanoic (0.8%) acids. We also established that silver birch pollen is characterized by high antioxidant activity. The measured value of TAA for aqueous pollen extracts was within 74.8–85.5%. For the ethanol extracts it was quantified within 60.3–95.0% and for the methanol extracts – 46.1–92.6%. The Tukey test was used to determine the differences between the means at a level of P < 0.05. A strong correlation coefficient (0.70) was defined between the protein content and the TAA of aqueous extracts. In general, the Ukrainian and Slovak samples of pollen differ in the fatty acid composition of lipids and aqueous and ethanol TAA extracts. Pollen of B. verrucosa should be used for diagnostic, therapeutic and prophylactic purposes as close as possible to the place of origin.