Cytokinin and Auxin Participation in Nodulation Process Regulation in Legumes

The article summarizes the data on physiological role of phytohormones – cytokinin and auxin - in initiation of root cortical cells division resulting in formation of root nodule primordium and its further organogenesis. High level of cytokinin and low level of auxin have been proven to be a prerequisite for this process. The mechanism providing the increase in cytokinin : auxin ratio is linked to inhibiting auxin transport from aerial organs to the root with the involvement of cytokinin signaling. Decrease in cytokinin : auxin ratio at the background of inhibiting cytokinin signaling initiates formation of lateral roots. Alternative role of rhizobial Nod-factor, cytokinin and flavonoids in root nodule organogenesis is discussed. Schemes of reactions and compounds participating in initiating of nodule primordium and lateral roots formation are presented

Structural changes in friction-stir welded Al-Li-Cu-Sc-Zr (1460) alloy

Structure and properties of Al-2.3%Li-3%Cu-0.1%Sc-0.1%Zr (1460) were studied after FSW on thin cold-rolled sheets with the thickness of 2mm. Sheets were aged in the T8mode. During FSW, severe plastic deformation and material flow occurs at the temperature lower than melting temperature. Welding was performed at the tool rotation speed 2880 rps. The tool was moved along the weld joint at the constant speed 16m/h. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2058

Rhythmical changes of a level nitric oxide (NO) in roots etiolated seedlings of pea (Pisum sativum L.) and influence of exogenous calcium

Studied time dynamics (during 60 mines) a level oxide nitric (NO) in cross cuts of roots 2 – day etiolated seedlings of pea sowing (Pisum sativum L.) by use of fluorescent probe DAF-2DA and a fluorescent microscope depending on action exogenous calcium (Ca2+). During an exposition of seedlings on water, solution CaCl2 are shown fluctuation in level NO in roots – his increase and decrease that testifies to the certain rhythm in generation NO. Exogenous factors (Ca2+) change time dynamics of level NO in comparison with variant “water”. Ca2+chelate EGTA removes action exogenous calcium on rhythmical change of a level NO in roots. Results are discussed in aspect of close interference of signaling systems and molecules (Ca2+, NO, Н2О2)

Physiological role of calcium in legume-rhizobium symbiosis

Literature data on the physiological role of calcium (Ca2+) in legume-rhizobium symbiosis development on initial stages - the infection and symbiotic structures formation, are generalized. The questions about the Ca2+ function in plants, special feature the formation of legume-rhizobium symbiosis and role of calcium in the interaction of two organisms are considered. Data on the interaction of ROS and Ca2+ in the development of the legume-rhizobium symbiosis and the relationship of NADPH-oxidase activity with the calcium signaling system are analyzed. The special attention is given to the role of Ca22+-spiking and calcium and calmodulin-like kinase in the initiation of plant symbiotic ways operation leads to infection and the formation of symbiotic structures

Пленочные материалы на основе полиэтилена с наночастицами кремния и карбида кремния

Polyethylene films containing 0.1-1.5% of mass of n-SiС and n-Si nanoparticles have been produced by the extrusion method. Using the spectral analysis method, it was found that the obtained films absorb UV radiation in the range 200-400 nm, which is harmful to organic substance. The average particle sizes and the quality of their dispersion in the films were determined by X-ray diffraction analysis. Using differential scanning calorimetry and physical and mechanical tests, it was found that nanoparticles did not affect the formation of the internal structure of the matrix polyethylene. The degree of crystallinity, the melting point and crystallization remain unchanged. The properties of the film surface, studied by the tribological, triboelectric methods and the determination of the wetting angle, remain constant and do not differ from the properties of PE films with nanoparticle content 0.1-1%. At 1.5% n-SiC content, a change in the surface microrelief is diagnosed, leading to a slight increase in the friction coefficient of the films. The polyethylene films filled with n-SiС and n-Si obtained in this work are recommended for use as UV protective coatings for various purposes.В настоящей научно-исследовательской работе экструзионным способом были получены полиэтиленовые пленки, содержащие 0,1-1,5% (мас.) наночастицы n-SiС и n-Si, полученные плазмохимическим методом. С помощью спектрального метода анализа установлено, что полученные пленки поглощают УФ-излучение в диапазоне 200-400 нм, губительное для органической материи. Методом рентгеноструктурного анализа были определены средние размеры частиц и качество их диспергирования в пленках. Методами дифференциальной сканирующей калориметрии и физико-механических испытаний установлено, что наночастицы не влияют на формирование внутренней структуры полиэтилена (ПЭ) матрицы. Степень кристалличности, температуры плавления и кристаллизации остаются неизменными. Свойства поверхности пленок, исследуемые трибологическими, трибоэлектрическими методами и определением краевого угла смачивания, остаются постоянными и не отличаются от свойств ПЭ-пленок при содержании наночастиц от 0,1 до 1%. При 1,5% содержании n-SiС диагностируется изменение микрорельефа поверхности, приводящее к небольшому росту коэффициента трения пленок. Полученные в работе наполненные n-SiС и n-Si полиэтиленовые пленки рекомендуются для использования в качестве УФ защитных покрытий различного назначения

Modification of nanocrystalline silicon by polymers for biomedical applications [МОДИФИКАЦИЯ НАНОКРИСТАЛЛИЧЕСКОГО КРЕМНИЯ ПОЛИМЕРАМИ ДЛЯ БИОМЕДИЦИНСКИХ ПРИЛОЖЕНИЙ]

In this paper, it is proposed to use polymer-modified composite materials based on nano-crystalline silicon (nc-Si) as an alternative to organic fluorescent quantum dots traditionally used in medicine. A distinctive feature of nc-Si is a high absorption coefficient in the near UV and blue-violet range and the ability to transmit light in the visible region of the spectrum. The main ad-vantage of silicon-based nanoparticles for in vivo use is their biodegradability and the absence of toxic properties. For hydrophilization of silicon nanoparticles, their surface was modified by am-phiphilic biocompatible polymers: polyvinylpyrrolidone, a copolymer of maleic anhydride and 1-octadecene, cremophore, which is a polyoxyethylene derivative of hydrogenated castor oil. Silicon nanoparticles (nc-Si) with an average diameter of 4.5 nm, synthesized by annealing of SiO at 1150 °C, and functionalized with 1-octadecene photoluminescent in the red-infrared spectral region were used. The presence of the polymer shell on the surface of the nanoparticles was confirmed by FTIR spectroscopy. The sedimentation and aggregative stability of the particles in water were analyzed. It is shown that after the nc-Si polymer modification, the photoluminescent properties of nanopar-ticles are retained although the photoluminesce maxima were shifted to the blue region. Colori-metric MTT-assay of the cytotoxicity of the nanoparticles modified with polymers to monoclonal cells of human erythroleukemia K562 showed no toxicity for cells in culture at a particle concen-tration of up to 50 μg/ml. Subcellular localization of silicon nanoparticles into the human cervical carcinoma cell line HeLa was shown by means of fluorescence microscopy. The obtained polymer-modified nc-Si particles can be recommended for the purposes of bioimaging in in vitro and in vivo applications. © 2019, Ivanovo State University of Chemistry and Technology

МОДИФИКАЦИЯ НАНОКРИСТАЛЛИЧЕСКОГО КРЕМНИЯ ПОЛИМЕРАМИ ДЛЯ БИОМЕДИЦИНСКИХ ПРИЛОЖЕНИЙ

In this paper, it is proposed to use polymer-modified composite materials based on nanocrystalline silicon (nc-Si) as an alternative to organic fluorescent quantum dots traditionally used in medicine. A distinctive feature of nc-Si is a high absorption coefficient in the near UV and blue-violet range and the ability to transmit light in the visible region of the spectrum. The main advantage of silicon-based nanoparticles for in vivo use is their biodegradability and the absence of toxic properties. For hydrophilization of silicon nanoparticles, their surface was modified by amphiphilic biocompatible polymers: polyvinylpyrrolidone, a copolymer of maleic anhydride and 1-octadecene, cremophore, which is a polyoxyethylene derivative of hydrogenated castor oil. Silicon nanoparticles (nc-Si) with an average diameter of 4.5 nm, synthesized by annealing of SiO at 1150 °C, and functionalized with 1-octadecene photoluminescent in the red-infrared spectral region were used. The presence of the polymer shell on the surface of the nanoparticles was confirmed by FTIR spectroscopy. The sedimentation and aggregative stability of the particles in water were analyzed. It is shown that after the nc-Si polymer modification, the photoluminescent properties of nanoparticles are retained although the photoluminesce maxima were shifted to the blue region. Colorimetric MTT-assay of the cytotoxicity of the nanoparticles modified with polymers to monoclonal cells of human erythroleukemia K562 showed no toxicity for cells in culture at a particle concentration of up to 50 μg/ml. Subcellular localization of silicon nanoparticles into the human cervical carcinoma cell line HeLa was shown by means of fluorescence microscopy. The obtained polymer-modified nc-Si particles can be recommended for the purposes of bioimaging in in vitro and in vivo applications.В настоящей работе предложено использовать полимермодифицированные композитные материалы на основе нанокристаллического кремния (nc-Si) в качестве альтернативы органическим флуоресцентным меткам, традиционно применяемым в медицине. Отличительной особенностью nc-Si является высокий коэффициент поглощения в ближнем УФ и сине-фиолетовом диапазоне и способность пропускать свет в видимой области спектра. Основным преимуществом наночастиц на основе кремния для использования in vivo является их биодеградируемость и отсутствие токсических свойств. Для гидрофилизации наночастиц кремния проведена модификация их поверхности амфифильными биосовместимыми полимерами: поливинилпирролидоном, сополимером малеинового ангидрида и 1-октадецена, кремофором, представляющим собой полиоксиэтилированное гидрированное касторовое масло. В работе использовали фотолюминесцирующие в красно-инфракрасной области спектра наночастицы кремния (nc-Si) со средним диаметром 4,5 нм, синтезированные отжигом SiO при 1150 °C и функционализированные 1-октадеценом. Наличие полимерной оболочки на поверхности наночастиц подтверждали ИК-Фурье спекроскопией. Проведен анализ седиментационной и агрегативной устойчивости полученных частиц в воде. Показано, что после модификации nc-Si полимерами фотолюминесцентные свойства наночастиц сохраняются, хотя модификация приводит к сдвигу спектров фотолюминесценции в коротковолновую область. Анализ цитотоксичности модифицированных полимерами частиц нанокремния, проведенный с помощью колориметрического МТТ-теста с использованием моноклонизированных клеток эритролейкоза человека К562, показал отсутствие токсичности для клеток в культуре при концентрации частиц до 50 мкг/мл. С помощью флуоресцентной микроскопии показана субклеточная локализация наночастиц кремния с использованием клеточной линии карциномы шейки матки человека HeLa. Полученные полимермодифицированные частицы nc-Si могут быть рекомендованы для целей биоимиджинга в in vitro и in vivo приложениях