Ecological and biological features of Triglochin maritima L. in the biotopes of the littoral zone with different degree of flooding on the coast of the White Sea

The study of Triglochin maritima L. was carried out on the Pomor (western) coast of the White Sea, in the Republic of Karelia (64°22'81"N, 35°93'14"E). Morphological analysis of aboveground and underground parts of the clones was performed on virginal plants. Anatomical analysis of leaf sheaths of the current year shoots, rhizomes and adventitious roots was carried out. The viability of pollen was assessed by determining the relative share of normally developed and malformed pollen grains. The content of heavy metals was determined in the soil, sea water and plant samples. The study was carried out on a model transect in the littoral zone on three test plots representing the lower littoral; the middle and the upper littoral zones. Adaptation to wave and storm impact was manifested in a well-developed system of underground organs. In the lower littoral, underground part surpasses the aboveground vegetative organs in terms of the mass and the formation of mechanical tissues. This allows the plants to anchor stronger in the substrate. Pollen analysis confirmed the adaptability of T. maritima plants to the conditions of the lower littoral by a high percentage of normal and, consequently, fertile pollen, which ensures sexual reproduction of the species. T. maritima can be considered as a Fe hyperaccumulator as the plant accumulates very high levels of Fe (22–34 g kg-1), especially in the lower and middle littoral zones, both in underground and aboveground organs. The ability of T. maritima plants to actively deposit metals was revealed on the basis of the coefficient of biological absorption of metals and makes it possible to suggest potential possibility of using the species in phytoremediation technologies on coastal territories

Low-Molecular Antioxidants Help Rare Orchids to Survive in Serpentine Dumps

В статье представлены результаты исследования морфофизиологических и биохимических характеристик орхидеи Epipactis atrorubens, произрастающей в естественном лесном фитоценозе и техногенно нарушенных местообитаниях. Изучены параметры листовой пластинки, водный режим листьев, уровень перекисного окисления липидов, а также содержание фотосинтетических пигментов и низкомолекулярных антиоксидантов в листьях растений. Результаты исследования показали, что адаптивные структурные перестройки листа и активация системы антиоксидантной защиты определяют не только способность редкого вида орхидей выживать в неблагоприятных условиях, но и успешно адаптироваться к ним.The article presents the results of a study of morphophysiological and biochemical characteristics of the orchid Epipactis atrorubens, growing in natural forest community and technogenic habitats. Leaf mesostructure, water regime and biochemical features (level of lipid peroxidation, content of photosynthetic pigments and low molecular weight antioxidants) of plants have been studied. The present study showed that the adaptive leaf structural rearrangements and activation of antioxidant defense system determine not only the ability of a rare orchids to survive in negative conditions, but also to successfully adapt to them

QED cascades induced by circularly polarized laser fields

The results of Monte-Carlo simulations of electron-positron-photon cascades initiated by slow electrons in circularly polarized fields of ultra-high strength are presented and discussed. Our results confirm previous qualitative estimations [A.M. Fedotov, et al., PRL 105, 080402 (2010)] of the formation of cascades. This sort of cascades has revealed the new property of the restoration of energy and dynamical quantum parameter due to the acceleration of electrons and positrons by the field and may become a dominating feature of laser-matter interactions at ultra-high intensities. Our approach incorporates radiation friction acting on individual electrons and positrons.Comment: 13 pages, 10 figure

POLYFLUOROALKYL-2-(HET)ARYLHYDRAZONO-1,3-DICARBONYL COMPOUNDS IN INTRAMOLECULAR CYCLIZATION REACTIONS

This work was financially supported by the Program UB RAS (Grant number 18-3-3-13)

Properties of electrons scattered on a strong plane electromagnetic wave with a linear polarization: classical treatment

The relations among the components of the exit momenta of ultrarelativistic electrons scattered on a strong electromagnetic wave of a low (optical) frequency and linear polarization are established using the exact solutions to the equations of motion with radiation reaction included (the Landau-Lifshitz equation). It is found that the momentum components of the electrons traversed the electromagnetic wave depend weakly on the initial values of the momenta. These electrons are mostly scattered at the small angles to the direction of propagation of the electromagnetic wave. The maximum Lorentz factor of the electrons crossed the electromagnetic wave is proportional to the work done by the electromagnetic field and is independent of the initial momenta. The momentum component parallel to the electric field strength vector of the electromagnetic wave is determined only by the diameter of the laser beam measured in the units of the classical electron radius. As for the reflected electrons, they for the most part lose the energy, but remain relativistic. There is a reflection law for these electrons that relates the incident and the reflection angles and is independent of any parameters.Comment: 12 pp, 3 fig

Динамика распространенности бронхиальной астмы у детей в Новосибирске

Six-year dynamics of epidemiology of bronchial asthma was analyzed in Novosibirsk according to a common standardized protocol of the "International Study of Asthma and Allergic Diseases in Children" (ISAAC) programme. The pathology spread was studied using a total surveying among first-form and eight-form pupils (the survey involved 7291 pupils 1996, 6631 ones in 1999 and 6943 children in 2002). The results showed stable spread of bronchial asthma symptoms among the senior and junior pupils and prevalence of mild asthma with rare exacerbations in both the groups. A progredient growth of severe asthma attack rate was noted in eight-form pupils. An increase in frequency of combined upper and lower airway pathologies was registered with reduction in skin atopy rate. A problem of underestimating of the pathology was discussed.Исследована 6-летняя динамика эпидемиологии бронхиальной астмы по единым стандартизованным протоколам программы "Международное исследование астмы и аллергических заболеваний у детей" (ISAAC) в Новосибирске. Изучение распространенности патологии проводилось при сплошном анкетировании учеников 1-х и 8-х классов (7291 школьник в 1996 г., 6631 — в 1999 г. и 6943 — в 2002 г.). В динамике выявлены стабильная распространенность симптомов бронхиальной астмы у старших и младших школьников, сохранение преобладания легких редко рецидивировавших форм патологии в обеих возрастных группах. Отмечен прогредиентный рост тяжелых приступов удушья у восьмиклассников. В популяции школьников зарегистрировано увеличение сочетанного поражения верхних и нижних отделов респираторного тракта с сокращением частоты кожных форм атопии. Отражена проблема гиподиагностики патологии

Феномен подавления ДНК-метилтрансферазы 3А при формировании резистентного фенотипа в клетках рака молочной железы

Introduction. Rearrangement of molecular pathways and activation of bypass signaling determine the progression of tumor cell resistance to various drugs. Study of the common features of resistant formation mechanisms is essential for breast and other cancer beneficial treatments.Materials and methods. The present work was performed on estrogen receptor α ERα-positive (ERα – estrogen receptor α) McF-7 breast cancer cells, established sublines resistant to the mTOR inhibitor rapamycin or antiestrogen tamoxifen, and ERα-negative MDA-MB-231 breast cancer cells. Methods used include MTT test, transient transfection, immunoblotting, real-time polymerase chain reaction and methylation analysis by bisulfite pyrosequencing.Results. We have shown that the resistance of breast cancer cells to targeted and hormonal drugs is associated with the suppression of DNA methyltransferase 3A (DNMT3A) and respective changes in DNA methylation; DNMT3A knockdown results in the partial resistance to both drugs demonstrating the pivotal role of DNMT3A suppression in the progression of cell resistance.Conclusion. Totally, the results obtained highlight the possible mechanism of tumor cell resistance to targeting/hormonal drugs based on the deregulation of DNMTs expression and demonstrate  direct connection between DNMT3A suppression and resistance progression.Введение. Переключение сигнальных путей и активация параллельных сигнальных каскадов относятся к ключевым факторам, определяющим развитие резистентности опухолевых клеток, и изучение механизмов подобной реаранжировки является одной из актуальных задач современной онкологии.Материалы и методы. Настоящая работа выполнена на ERα-положительных  (ERα – эстрогеновый рецептор α) клетках рака молочной железы MCF-7 и полученных из них сублиниях, устойчивых к ингибитору mTOR рапамицину или антиэстрогену тамоксифену, а также на ERα-отрицательных клетках рака молочной железы MDA-MB-231. Используемые методы включают тест МТТ, транзиторную трансфекцию, иммуноблоттинг, полимеразную цепную реакцию в реальном времени и анализ метилирования с помощью бисульфитного пиросеквенирования.Результаты. Мы показали, что резистентность клеток рака молочной железы к таргетным и гормональным препаратам связана с подавлением ДНК-метилтрансферазы 3А (DNMT3A) и соответствующими изменениями в метилировании ДНК. Нокдаун DNMT3A приводит к частичной резистентности к обоим препаратам, что демонстрирует ключевую роль подавления DNMT3A в развитии резистентности опухолевых клеток.Заключение. В целом, полученные результаты свидетельствуют о возможном механизме формирования устойчивости опухолевых клеток к таргетным/гормональным препаратам, основанном на дерегуляции экспрессии DNMT, и демонстрируют прямую связь между подавлением DNMT3A и развитием резистентности

Particle Acceleration in Pulsar Wind Nebulae: PIC modelling

We discuss the role of particle-in-cell (PIC) simulations in unveiling the origin of the emitting particles in PWNe. After describing the basics of the PIC technique, we summarize its implications for the quiescent and the flaring emission of the Crab Nebula, as a prototype of PWNe. A consensus seems to be emerging that, in addition to the standard scenario of particle acceleration via the Fermi process at the termination shock of the pulsar wind, magnetic reconnection in the wind, at the termination shock and in the Nebula plays a major role in powering the multi-wavelength signatures of PWNe.Comment: 32 pages, 16 figures, to appear in the book "Modelling Nebulae" edited by D. Torres for Springer, based on the invited contributions to the workshop held in Sant Cugat (Barcelona), June 14-17, 201