Аннотация.На примере лабораторной культуры Tetraselmis viridis (Rouchijajnen) показан способ реализации максимальной продуктивности в квазиплотностатном процессе выращивания микроводорослей.Экспериментальной основой для расчета оптимальных условий служит накопительная кривая при конкретных условиях выращивания.Анализ кривой позволил выделить участок линейного роста с 4-х по 6-е сутки выращивания, определить максимальную продуктивность ( 0,42 г/л·сут.)и найти границы плотностей (1,32-2, 37 г/ л), внутри которых микроводоросли растут с максимальной скоростью.При переходе в квазиплотностатный режим культивирования оптимальный диапазон сужается сверху на величину прироста за время между разведениями культуры.Для T. viridis время роста внутри оптимального диапазона плотностей превышает сутки, что позволяет контролировать плотность и осуществлять отбор только один раз в сутки, поддерживая продуктивность на максимальном уровне.При ежесуточном отборе и разбавлении культуры оптимальный диапазон плотностей составляет 1,32-1,95 г/ л.Пер еход в квазиплотностатный режим выращивания T. viridis при ежесуточном разбавлении плотности до 1,4 г/л экспериментально подтвердил расчетные данные.На накопительной кривой роста точка окончания фазы максимальной продуктивности характеризуется резким снижением скорости роста, что указывает на смену фактора, лимитирующего рост при плотности культуры выше 2,37 г/л.При этом дальнейший линейный рост указывает на то, что таким фактором является недостаток потока углерода на клетку.Экспериментальная проверка подтвердила это предположение.В дополнительном опыте поток углерода с воздухом был снижен за счет отключения распылителя.Это привело к снижению диапазона оптимальных плотностей с 0,95 до 0,69 г/л при максимальной продуктивности 0,26 г

The red microalga Porphyridium purpureum (Bory de Saint-Vincent, 1797) Drew et Ross, 1965 is of great interest to researchers as a source of various biologically valuable substances, with their content in cells being determined by cultivation conditions. Phycobiliproteins concentration in P. purpureum cells depends directly on nitrogen concentration in the culture medium and cell irradiance. Semi-continuous cultivation allows maintaining these parameters at a level given. The aim of the work was to study P. purpureum culture growth and B-phycoerythrin (B-PE) accumulation and production at low irradiance, with minimal rates of pigment photodestruction. P. purpureum semi-continuous (quasi-continuous) cultivation was carried out at a specific flow rate of 0.1 and 0.2 day−1 and mean surface irradiance of 5 and 25 W·m−2. P. purpureum culture productivity increased by 1.6–17 times both with a rise in surface irradiance 5 to 25 W·m−2 and an increase in the medium specific flow rate 0.1 to 0.2 day−1. Maximum productivity values for the experimental conditions (0.21 g·L−1·day−1) were recorded at 25 W·m−2 and 20 % medium specific flow rate, but those were 1.5–2 times lower than the precalculated ones. In P. purpureum cells, protein and B-PE concentrations decreased both with an increase in surface irradiance (by 15–20 %) and with a rise in a specific flow rate (by 1.5 times) for all the variants. The shifts in protein and B-PE concentration in P. purpureum culture had a unidirectional character as well; those mainly corresponded to the shift in the culture density. P. purpureum B-PE productivity increased by 1.5–1.9 times with a rise in surface irradiance 5 to 25 W·m−2. Maximum B-PE productivity (13 mg·L−1·day−1) was recorded for the variants of the experiment with a surface irradiance of 25 W·m−2 (0.1 and 0.2 day−1). An increase in specific irradiance of P. purpureum cells 7 to 26 W·g−1 resulted in a rise in biomass productivity by 2.6 times; in B-PE productivity, by 1.8 times; and in protein productivity, by 1.7 times. In the experiment, irradiance was the factor determining the production characteristics of P. purpureum culture, and it was confirmed by the data obtained.

The aim of this study was to examine 3D structures of DNA aptamers, thrombin inhibitors. •The main objective was to study 3D structure 15TBA, RE31, NU172 aptamers using the small-angle X-ray scattering method. The size of 15TBA was 4.5 nm, which corresponds to a partially unfolded conformation. The CD spectrum of Nu172 in the presence of 50 mM strontium ions indicates the presence of an antiparallel G-quadruplex, the concentration o f which drops at 50°C. NU172 does not have a rigid structure, apparently due to the presence of a guanine residue in the GT loop. The NU172 aptamer does not form a stable conformation in solution either without ions or with Ba2+ and Sr2+ ions. • It was shown that there is possibility of aptamers transition from one conformation to another dependently on concentration and temperature confirms that the potassium ion is a unique stabilizing ion of natural molecules containing G-quadruplexes

The research deals with theoretical calculation of the maximal growth rate of green halophilic microalga Dunaliella salina in the conditions of natural illumination at South regions of Russia (Sevastopol city as an example). The calculation is based on the concept that microalgae growth rate is defined as the difference between gross productivity and endogenous biomass expenditure rate. Gross productivity is a function of photosynthetic active radiation (PAR), absorption coefficient and energy utilization efficiency. For maximal productivity calculation it is suggested that all incident of the pond surface light energy is absorbed by microalgae culture. As far as photobiosynthesis efficiency value depends on illuminance in a complex way, we used average value 5.58%. The rate of endogenous biomass expenditure was determined based on the value of night losses, which for D. salina was about 5%. Computations showed that for D. salina maximum biomass gain makes 26 g DW/(m(2) . day). It is shown that the maximum observed productivity of D. salina in the conditions of natural light in the southern regions of Russia cannot exceed 26 g DW/(m(2) . day).

On p. 679 in the list of authors and affiliations instead of: 1 Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127726 Moscow, Russia 2 Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia 3 Institute of Fundamental Problems of Biology of the Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia 4 Kovalevski Institute of Biology of the Southern Seas, Russian Academy of Sciences, 299011 Sevastopol, Russia 5 Lomonosov Moscow State University, Faculty of Biology, 119991 Moscow, Russia Should read: 1 Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, 127726 Moscow, Russia 2 Kovalevski Institute of Biology of the Southern Seas, Russian Academy of Sciences, 299011 Sevastopol, Russia 3 Institute of Fundamental Problems of Biology of the Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia 4 Bach Institute of Biochemistry, Research Center of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia 5 Lomonosov Moscow State University, Faculty of Biology, 119991 Moscow, Russia

It is proposed to use data on the hydrocarbon content in phytoplankton contained in a studied water sample to calculate the biogenic background of hydrocarbons, without which the assessment of the degree of oil pollution of aquatic ecosystems would be incorrect. Algae were grown in sterile flasks to accumulate the biomass required for analysis. The amount of hydrocarbons isolated from lipid fractions of different algal species by thin layer chromatography varied from 0.004 to 0.007 mg per 1 mg of phytoplankton. The lipid content varied from 4.5 to 6.2% in different phytoplankton species; the concentration of hydrocarbons was 8–11% of the total lipid weight. Depending on the phytoplankton species, the composition of paraffin hydrocarbons was dominated by C17, C21, C25, C29, and C31 odd n-alkanes.

The selective properties of a solution of oligonucleotide specific to IL-6 on the concentration of IL-6 in mixed saliva of patients with oral inflammatory processes were studied using SDS-PAGE by electrophoresis and enzyme immunoassay. The application of these methods showed that in the mixed saliva of patients after rinsing with a solution of an oligonucleotide specific for IL-6, the amount of IL-6 decreases. The ELISA Kit and 20% SDS-PAGE showed the highest sensitivity to determine the concentration of IL-6 in saliva, which should be considered in clinical laboratory practice.

The work is focused on modeling of chlorophyll and carotenoids content dynamics in the in cells of the unicellular algae D. salina , living in salt water, at carotenogenesis induction phase. A mathematical model of pigments content in microalgae cells, which experience excess of light energy and the limit of nutrient medium mineral components, is proposed. The model is based on assumption, that observed rate of variation in pigment concentration is an algebraic sum of the rates of synthesis, photodestruction and partial recovery of photo-oxidized pigments. The rate of secondary carotenoids synthesis does not depend on external conditions and is determined by the quantity of key enzyme complex and its turnover rate. The rate of secondary carotenoids and chlorophyll photodestruction depends on the effective light intensity and is proportional to the amount of absorbed photosynthetically active radiation energy. The verification of the derived equations was conducted in the course of D. salina cultivation at the carotenogenesis stage. The specific rate of chlorophyll a photodestruction was determined, which resulted in 0.12 days –1 . The secondary carotenoids concentration increases up to the maximum value, which is determined by the ratio of synthesis and photodestruction specific rates, as well as the maximum culture density. Under conditions of natural light in the Sevastopol region, the maximum concentration of carotenoids was 18.33 mg/l or 0.73 g/m 2 .

DNA aptamers (oligonucleotides) interacting with thrombin exosite I contain G-quadruplex, two T-T, and one T-G-T loops in their structure. They prevent exosite I binding with fibrinogen and thrombin receptors on platelet surface, thereby suppressing thrombin-stimulated formation of fibrin from fibrinogen and platelet aggregation. Earlier, we synthe-sized original antithrombin aptamer RE31 (5′-GTGACGTAGGTTGGTGTGGTTGGGGCGTCAC-3′) that contained (in addition to G-quadruplex) a hinge region connected to six pairs of complementary bases (duplex region). In this study, we compared properties of RE31 aptamer and its analogues containing varying number of bases in the duplex region and nucleotide insertions in the hinge region. Reduction in the number of nucleotides in the duplex region by 1 to 4 pairs (in comparison with RE31 aptamer) resulted in the decrease of the structural stability of aptamers (manifested as lower melting temperatures) and their ability to inhibit thrombin-stimulated fibrin formation in human blood plasma in tests of thrombin, prothrombin, and activated partial thromboplastin times. However, an increase in the number of bases by 1 to 2 pairs did not cause significant changes in the stability and antithrombin activity of the aptamers. Insertions into the hinge region of RE31 aptamer decreased its antithrombin activity. Investigation of RE31 antithrombotic properties demonstrated that RE31 (i) slowed down thrombin formation in human blood plasma (thrombin generation test), (ii) accelerated lysis of fibrin clot by tissue plasminogen activator in in vitro model, and (iii) suppressed arterial thrombosis in in vivo model. Based on the obtained data, RE31 aptamer can be considered as a potentially effective antithrombotic compound.

The paper presents a mathematical model of light-dependent chlorophyll concentration in the marine microalgae biomass. The model is based on the concept of biomass as the sum of reserve and structural macromolecular forms of organic cell matter. At the same time, chlorophyll refers to structural forms of biomass. Using such concepts, it is possible to apply known equations for light-dependent content of structural forms in biomass. The proposed equation describes well the experimental results obtained in a number of experiments with the chlorophyllostate culture Tetraselmis viridis.

Представлена математическая модель светозависимого содержания хлорофилла в биомассе морских микроводорослей. Основой модели служит представление о биомассе как сумме резервных и структурных макромолекулярных форм органического вещества клеток. При этом хлорофилл относится к структурным формам биомассы. Используя такие представления, можно применять известные уравнения для светозависимого содержания структурных форм в биомассе. Предложенное уравнение хорошо описывает результаты, полученные в экспериментах с хлорофиллостатной культурой Tetraselmis viridis.

A new explanation for linear growth microalgae culture density is proposed. Equations describing the dependence of light absorption coefficient and the specific rate of biomass synthesis on chlorophyll concentration are obtained. The specific extinction coefficient for Tetraselmis virilis culture (0.008 m-2 · mg chlorophyll a) is calculated.

Предложено новое объяснение линейного роста плотности культур микроводорослей. Получены уравнения, описывающие зависимость коэффициента поглощения света и удельной скорости синтеза биомассы от концентрации хлорофилла а. Рассчитан удельный коэффициент экстинкции для культуры Tetraselmis viridis, который составил 0,008 мг · м-2 хлорофилла а.

Antithrombin DNA aptamersRE31 are single-chain oligonucleotides that fold into three-dimensional forms allowing them to bind the enzyme with high affinity and inhibit its activity in vivo. They are rapidly degraded by a nonspecific nuclease, and, to prolong the lifetime of the aptamer DNA in the bloodstream, it is necessary to coat it with a polymer envelope. A new approach to solving this problem based on preparation of DNA-polyelectrolyte complexes with a minimal particle size that can circulate with blood flow. In our experiments, the negatively charged aptamer DNA RE31 was coated step-by-step with positively charged protamine. They had protamine/aptamer ratios of 0.2/1 and 0.4/1 by charge, with particle size being determined by dynamic light scattering. The aptamer DNA-protamine complexes were administered to rats, followed by ex vivo analysis of blood samples. The results showed that prothrombin time (PT) increased by a factor of 5.6-6.7 within 2 h after injection and remained at approximately the same level for 6 h, while injections of pure protamine did not lead to any noticeable change in clotting time. Thus, complexation with protamine proved to prolong the inhibitory activity of the RE31 DNA aptamer.

We used aptamers, which are functional equivalents of antibodies, in order to develop a nanosensor immunoassay system based on magnetic nanoparticles and a SQUID magnetometer. Selection was used to obtain DNA aptamers to interleukin-6; their affinity to the target protein was characterized by surface plasmon resonance. It was shown that the biotinylated aptamer binds to magnetic nanoparticles that were functionalized with streptavidin.