Species with a high resistance to hypoxia are usually characterized by an increased H 2 S tolerance of hydrogen sulfide; however, high anaerobic potential cannot be the only explanation for survival in an environment with elevated concentrations of sulfides. The activity of oxidoreductases, as well as parameters of adenylate system were studied in the tissues of hypoxia/anoxia-tolerant clam Anadara kagoshimensis (Tokunaga, 1906) under conditions of experimental H 2 S loading (HSL). Adult specimens with a shell height of 26–38 mm are used. The control group of clams is kept in an aquarium with an oxygen concentration of 7.0–7.1 mg/L (normoxia). The experimental group is exposed to the effect of HSL created by dissolving sodium sulfide (H 2 S donor) in water to a final concentration of 6 mg S 2– /L; exposure time is 24 h. After the first day of the experiment, the level of O 2 in water is 1.8 mg/L and there is no hydrogen sulfide. Some of the clams are exposed to repeated hydrogen sulfide loading (second day of the experiment), and Na 2 S is introduced to a final concentration of 9 mg S 2– /L; by the end of the second day, 1.9 mg S 2– /L and trace concentration of O 2 (0.03 mg/L) are registered. In the first days of HSL, a high activity of malate dehydrogenase (MDH) against the background of a significant suppression of the activity of lactate dehydrogenase (LDH) and an increase in the values of MDH/LDG index persists; this reflects a strengthening of anaerobic processes in the tissues of anadara with relatively high concentrations of О 2 in water (1.8 mg/L). After the second day of HSL, the activity of oxidoreductases in the clam tissues does not change when compared with the first day; however, the value of adenylate energy charge (AEC) persists against the background of a relative decrease in [ATP]. The retention of AEC indicates the ability of the anadara to exist under conditions of hydrogen sulfide contamination and acute forms of hypoxia/anoxia.

The activities of cytosolic oxidoreductases (malate and lactate dehydrogenases) and the level of ATP production in the hypoxic resistive tissues of Scorpaena porcus Linnaeus, 1758 were studied. It was found that “oxyphilic” tissues (structures of the brain, gills) are pre-adapted to hypoxia, since under normal conditions they had high MDH activity and an increased MDH/LDH ratio, the value of which was 10 to 20 times higher than that in the liver and white muscles. Moreover, in the relatively “young” brain divisions (forebrain, diencephalon, midbrain) the aerobic pathway of carbohydrate metabolism predominated. The ATP content decreased in a line of examined tissues as follows: white muscles → liver → medulla oblongata → gills → forebrain, diencephalon and midbrain. The ATP level in white muscles was an order of magnitude higher than in “oxyphilic” tissues and it probably served for the provision of throwing strategy for hunting of bottom predator.

The fish heart is a unique model to compare the resistance to hypoxia of its two chambers (atrium and ventricle), which are different in the structure and functional loading. The activity of oxydoreductases malate dehydrogenase (MDH, 1.1.1.37) and lactate dehydrogenase (LDH, 1.1.1.27), as well as the parameters of the adenylate system in the heart chambers of a Black Sea scorpaena, were studied under acute hypoxia (0.9–1.2 mg O2·L–1, 90 min). Despite the leading functional role of the ventricle, MDH activity in this heart compartment tended to decrease compared to the atrium in the absence of differences in LDH activity. At the same time, the difference in the level of adenylates (ATP, ADP, AMP), total adenylate pool (AP), and adenylate energy charge (AEС) between the atrium and ventricle was statistically nonsignificant, although the absolute value of the ventricular AP was almost twice as large as the atrial AP. The AEC values of the atrium and ventricle perfused only with venous blood did not exceed ~0.7 (vs. the maximum of this parameter ~0.9–1.0), apparently reflecting the energy status of tissues initially adapted to hypoxia. Under acute hypoxia, there were found two strategies for energy metabolism transformation in the heart chambers in the form of a 2.4-fold drop in MDH activity (р < 0.05) in the atrium and a 2.2-fold increment in LDH activity (р < 0.05) in the ventricle. Probably, the decline in MDH activity in the atrial tissue was determined by a more passive function of this heart chamber in providing the blood flow. The exposure to acute hypoxia led to a decrease in the level of adenylate nucleotides and an AEC decline in the heart chambers, as pronounced most distinctly in the ventricular myocardium. When decreasing PO2, the AEC in the heart chambers shifted within quite a narrow range (from 0.7 to 0.6), indicating the retention of a certain stationary energy status achieved by inhibition of ATP consumption or demand. The putative mechanism for retaining the AEC may be based on the negative chronotropic effect of hypoxia.

The fish heart is a unique model to compare the resistanceto hypoxia of its two chambers (atrium and ventricle), which aredifferent in the structure and functional loads. The activity of oxydoreductasesmalate dehydrogenase (MDH, 1.1.1.37) and lactate dehydrogenase (LDH, 1.1.1.27),as well as the parameters of the adenylate system in the heart chambersof a Black Sea scorpaena, were studied under acute hypoxia (0.9–1.2mg O2·L–1, 90min). Despite the leading functional role of the ventricle, MDHactivity in this heart compartment tended to decrease compared tothe atrium in the absence of differences in LDH activity. At thesame time, the difference in the level of adenylates (ATP, ADP,AMP), total adenylate pool (AP), and adenylate energy charge (AEС)between the atrium and ventricle was statistically nonsignificant,although the absolute value of the ventricular AP was almost twiceas large as the atrial AP. The AEC values of the atrium and ventricleperfused only with venous blood did not exceed ~0.7 (vs. the maximumof this parameter ~0.9–1.0), apparently reflecting the energy statusof tissues initially adapted to hypoxia. Under acute hypoxia, therewere found two strategies for energy metabolism transformation inthe heart chambers in the form of a 2.4-fold drop in MDH activity(р < 0.05) in the atriumand a 2.2-fold increment in LDH activity (р <0.05) in the ventricle. Probably, the decline in MDH activity inthe atrial tissue was determined by a more passive function of thisheart chamber in providing the blood flow. The exposure to acutehypoxia led to a decrease in the level of adenylate nucleotidesand an AEC decline in the heart chambers, as pronounced most distinctlyin the ventricular myocardium. When decreasing PO2,the AEC in the heart chambers shifted within quite a narrow range(from 0.7 to 0.6), indicating the retention of a certain stationaryenergy status achieved by inhibition of ATP consumption or demand.The putative mechanism for retaining the AEC may be based on thenegative chronotropic effect of hypoxia.

Работа основана на материале, собранном в рейсах НИС «Профессор Водяницкий» в сезоны, близкие по гидрофизическим характеристикам: в октябре 2016 г. и в марте-апреле 2017 г. Были рассмотрены вариации распределения гетеротрофно-фотоавтотрофного индекса микропланктона (НРI), на основе соотношений концентраций АТФ (как показателя метаболически активной биомассы) и хлорофилла а (как показателя фотоавтотрофной ее части). Применен метод оценки соотношений биомасс гетеротрофной и фотоавтотрофной составляющих микропланктона, проведена оценка продукционно-деструкционной сукцессии сообщества. Показано, что в осенний сезон исследованные воды полигона, опираясь на содержание АТФ, можно оценить как мезотрофные, в весенний – близкие к эвтрофным. Судя по НРI, в осенний сезон на большей части акватории доминировали гетеротрофные формы микропланктона, в весенний – паритетные соотношения гетеротрофного и фотоавтотрофного микропланктона. При сравнении распределения метаболически активной биомассы и НРI, в осенний сезон стадию продукционно-деструкционной сукцессии микропланктона можно охарактеризовать как развивающуюся, в весенний – как зрелую.

В настоящей работе рассмотрены результаты гидрологических, гидрооптических и гидробиологических исследований, выполненных в фотической зоне северной части Чёрного моря в октябре 2016 г. Выявлены основные особенности формирования биооптической структуры и ее связь с гидрологическим режимом. Показано, что в зоне Севастопольского и Феодосийского антициклонов, параллельно с заглублением верхнего квазиоднородного слоя, отмечается и заглубление слоя максимальных значений концентрации общего взвешенного вещества. В южной части съемки, ближе к центру основного циклонического круговорота Чёрного моря, где глубина нижней границы верхнего квазиоднородного слоя минимальна, отмечается подъем слоя максимума концентрации общего взвешенного вещества. Установлено, что в октябре 2016 г. отмечалась аномально высокая прозрачность вод с малым диапазоном пространственной изменчивости. Показано, что в этот период наблюдались заметно более низкие связи между вертикальными распределениями концентрации общего взвешенного вещества и температурой, соленостью и плотностью по сравнению с летним периодом 2016 г. В пробах воды идентифицированы микроводоросли девяти отделов, типичных для данного сезона. Выявлено, что величины метаболически активной биомассы микропланктона в открытой части моря соответствовали значениям, характерным для олиго-мезотрофных вод, в то время как в прибрежье Крыма они были близки к эвтрофным характеристикам. Стадия продукционно-деструкционной сукцессии микропланктона - развивающаяся, с прогнозом на рост биомассы в последующем.

Масс-спектроМетрия в науках о жизни

С 14 по 18 октября 2019 года проходил очередной IX съезд Всероссийского масс-спектрометрического общества (ВМСО), в рамках которого была проведена VIII Всероссийская конференция с международным участием «Масс-спектрометрия и ее прикладные проблемы». Организаторы форума – ​ВМСО, Институт физической химии и электрохимии им. А. Н. Фрумкина РАН (ИФХЭ РАН) и Институт нефтехимического синтеза им. А. В. Топчиева РАН (ИНХС РАН). Итоги подводят руководители, организаторы и активные участники высокого научного собрания.

The effect of short-term hypoxia on the activity of oxidoreductases,malate dehydrogenase (MDH, 1.1.1.37) and lactate dehydrogenase (LDH,1.1.1.27) responsible for urgent adaptation to oxygen deficiency,was studied in the brain and gills (first branchial arch) of theBlack Sea scorpionfish Scorpaena porcus.The control group of fish was kept at 4.5–6.7 mg O2 L–1 (normoxia),experimental groups were exposed to 1.7–3.7 mg O2 L–1 (mildhypoxia) and 0.3–1.0 mg O2 L–1 (acutehypoxia); the exposure time was 90 min, water temperature 21–22°C.The dissolved oxygen level was reduced by saturating water withnitrogen. Hypoxia had no significant impact on the brain structures.Under acute hypoxia, MDH and LDH activities, the MDH/LDH index andATP level in the forebrain, diencephalon and midbrain (FDMB), aswell as in the medulla oblongata (MB), remained at the level ofcontrol values. Mild hypoxia caused a proportional rise in MDH andLDH activities and an increase in the ATP level in FDMB, most likely,due to a reduced demand for ATP in this brain region. This phenomenonis supposed to be based on the GABAergic mechanism of brain activityregulation, which is able to reduce energy demands of nervous tissuedue to increasing the GABAA receptor density.The gills were distinguished by minimum MDH and LDH activities atthe background of high MDH/LDH index values. Acute hypoxia led todecrease LDH activity and increase the MDH/LDH index in the gills, reflectingthereby a transition of this organ to an anaerobic operational mode.Under acute hypoxia, there was detected an increase in the relationshipwithin the “MDH activity ↔ LDH activity” system in all types oftissues (r = 0.81–0.94, p < 0.05–0.01), which is typicalof the species tolerant to oxygen deficiency. Apparently, this effectis based on MDH coupling with glycolytic substrates under conditionsof acute oxygen deficiency, which rules out excessive lactate accumulationunder metabolic depression.

. Based on the data collected during scientific expeditions of RV “Professor Vodyanitsky” in January, April, October 2016 and July 2017, spatial and temporal changes in distribution of microplankton ATP and chlorophyll α as indicators of metabolically active biomass and its photoautotrophic part, respectively, were analyzed. The heterotrophic-photoautotrophic index (HPI) was calculated from ratios of these biochemical parameters and used to assess the stages of production and destruction succession of microplankton community over these seasons. In the investigated area, the sites, which most often demonstrate sharp differences in biochemical parameters of microplankton from the general background, can be considered anomalous and subjected to anthropogenic impact, mainly associated with household and industrial effluents. In general, upon comparison of the distribution of the metabolically active biomass and its production part in the specified seasons the similarity in the values manifested itself in the shallow coastal waters of Crimea: low values for the waters near the western part of the peninsula were assessed to be oligo-mesotrophic; increased values for the waters adjacent to the Kerch Strait in the east were found to be meso-eutrophic. Based on the HPI values, the situation, most promising in terms of development of microplankton biomass and increase in water productivity was observed in the investigated area in autumn. Quite possibly, it is one of the key factors affecting seasonal migration of some fish species from the Azov Sea to the Black Sea in the autumn-winter season.

The effect of short-term hypoxia on the activity of oxidoreductases – malate dehydrogenase (MDH, 1.1.1.37) and lactate dehydrogenase (LDH, 1.1.1.27) in the scorpaena organs determining an urgent adaptation to oxygen deficiency – brain and gills (first branchial arch) was studied. The control group of fish was exposed to 4.5–6.7 mg O2 L –1 (normoxia), experimental groups were kept under 1.7–3.7 mg O2 L –1 (mild hypoxia) and to 0.3–1.0 mg O2 L –1 (acute hypoxia). The oxygen content in the water was reduced by saturating it with nitrogen. All groups of fish were ex- posed to examined condition during 90 min under 21–22 ° С. It was shown that hypoxia had not a significant im- pact on the brain structures of scorpaena. Under acute hypoxia MDH, LDH activity, MDH/LDH index and ATP content in forebrain, diencephalon, midbrain (FDMB) and medulla (MB) remained at the level of control values. Mild hypoxia caused a proportional rise of MDH, LDH activity and increased ATP level in FDMB like a consequence of the reducing need in ATP in these brain area. Above-mentioned phenomenon could be based on the GABA-ergic mechanism of the regulation of brain tissue activity that is able to reduce the energetic needs of the nervous tissue through the increased density in GABA A receptor apparatus. The gill tissue had a minimal activity of MDH, LDH on the background of high MDH/LDH index value. Acute hypoxia was accompanied by the drop in LDH activity and increased MDH/LDH which was related to anaerobic mode of operation in gill tissue. Under acute hypoxia there was an increase in the relationship in “MDH activity ↔ LDH activity” system (r = 0.81–0.94, p < 0.05–0.01) in all types of tissues, which is typical for the species tolerant to oxygen deficiency. Probably, this effect is achieved by the conjugation of MDH with glycolysis substrates in the conditions of acute O 2 deficiency, which excludes the accumulation of lactate during metabolic depression.

Influence of anoxia on the energy status of tissues of bivalve mollusk Anadara inaequivalvis Br. has been studied in experiment. Anoxia caused decrease of the adenylic nucleotides pool and energy potential of the tissues on the whole. This was expressed as decrease of the ATP and ADP fractions content; decrease of the adenylate energy charge (AEC) and phosphorylation potential (PhP). In 3 days of the experimental anoxia decrease of all studied parameters' values did not exceed 40−45%. It allows to assume observed changes of adenylate system state to have balanced character and to be functionally sufficient to maintain subbasal rate of metabolism.

Peculiarities of the course of metabolic processes in tissues of the bivalve mollusc Anadara inaequivalvis Br. were studied under conditions of experimental anoxia. In the absence of oxygen, in gill and foot the protein catabolism processes were found to be enhanced; this led to a decrease of the protein content and to an increase of the free amino acid and urea levels. Predominantly hydrolyzed were low molecular peptides, which was indicated by a decrease of the cathepsin D activity on the background of a rise of the γ-glutamyltranspeptidase activity. Anoxia was accompanied by enhancement of the succinate thiokinase and fumarate reductase reactions controlled by alanine and aspartate aminotransferases. This prevented accumulation of toxic lactate in tissues and allowed obtaining an additional macroerg resource. Metabolic processes in the mollusc hepatopancreas were oriented to production of amino acids.

The production potential of pelagic society is determined, mainly, by autotrophic microplankton functional capacity for biomass replenishment owing to photosynthesis. The biomass increase, on the one part, is strong dependent on a ratio of autotrophic and heterotrophic components of microplankton society. Thus, it may be essential and quite enough to define the microbiota physiological state and autotrophic component quota for vector definition of microplankton society development. One of the most objective methods of microorganisms' physiological state estimation is the adenilate energy charge (AEC) determination. AEC is calculated from adenine nucleotide (ATP, ADP and AMP) content ratio. It may theoretically lie in the range from 0 (with fully discharged system) up to 1 (with fully charged system). But substantively AEC varies in close limits during homeostasis: from 0.75 up to 0.99. The decrease of these values is evidence of organisms' physiological depression degree. The heterotrophic-photoautotrophic (HP) index gives information about microplankton heterotrophic and autotrophic components ratio. PH index is calculated from ATP and chlorophyll "α" content ratio multiplied by 100 (for safe using). In case of HP is from 10 up to 20 it indicates the heterotrophic and autotrophic biomass parity. HP increase is evidence of heterotrophic predominance and HP decrease – about autotrophic predominance. Works were carried out in the 7-th Ukrainian Antarctic Expedition in March 2002 at 20 field stations between 62°50' - 64°20'S latitude and 60° - 62°30'W longitude. The adenilates assays were carried out by sensitive chemiluminescent method. The chlorophyll “α” assays were carried out by the spectrophotometric method. The HP index analyses showed the autotrophic predominance in the vast area of the polygon, the considerable part of the region was reckoned in heterotrophic and autotrophic biomass equal area and insignificant part was with heterotrophic predominance. So one may conclude that AEC mainly reflected the physiological state of the autotrophic part of microplankton. Generally AEC changed from 0,39 up to 0,95 at average value 0,73. Despite of significant patchiness of AEC distributions, some prominent features of systems charge state are traced. The most oppressed physiological condition expressed in system discharging state up to threshold values of survival rates, was dated in the western and northern areas of the polygon, where the resource of biogenes is strongly exhausted owing to high biomass and acute pycnoclines, first of all, for phosphates. In spite of autotrophic predominance, the production potential is strongly reduced by the low level of AEC there. It should be expected the destruction processes predominance over production ones. On the contrary, on the greater part of polygon was under rather high degree of adenilate systems charged state. With considerable part of autotrophic content it testifies to high production potential uncharacteristic for late stages of succession is marked. Unfortunately, similar works in these latitudes were not carried out earlier and therefore there are no data to compare. But so high degree of adenilate systems charged state of microplankton society at the end of the vegetative season allows assuming, that the abnormal cold summer of 2002 with long-drawn freezing-over did not permit to gain a microplankton biomass on patterns of last years. This circumstance has to some extent saved a resource of biogenes for primary production during annual insolation peak and lag terms of microplankton development for the later period. This biochemical estimation method is especially convenient for high latitude waters due to the existence of the single-peak annual production succession.

Angular distribution of the 115In+ ions sputtered from the (111) and (1 1 1) polar faces of InSb single crystal has been experimentally studied. Angular and energy distributions of the 63Cu+ ions sputtered from the (100) Cu single crystal face were also studied. In the latter studies the use was made of a method permitting the energy distribution curve to be obtained in case of continuous cyclic passage through the various azymuthal angles of ion ejection. Such curve displays oscillations due to angular anisotropy of secondary ion emission and permits energy distributions to be obtained for all azymuthal angles of sccondary ion ejection (at given polar angles). The sputtering was under 5-10 keV Ne+ ion bombardment at a normal to the face. The ejection angles, energies, and masses of secondary ions were anialyzed using an installation which comprised a sector electrostatic energy analyzer with a 60° deflection angle and a magnetic mass-spectrometer. The angular distributions of the 115in+ and 65Cu+ ions were found to be similar to the corresponding distributions for neutral atoms observed during the Cu and InSb single crystal sputtering. It follows from the results of simultaneous studies of the 63Cu+ ion angular and energy distributions that relatively slow ions (up to 50-60 eV) are responsible for the angular distribution anisotropy. The distribution of the 63Cu+ high-energy component has bcen found to be practically isotropic.