Strong alkalinization of Chara cell surface in the area of cell wall incision as an early event in mechanoperception

AbstractMechanical wounding of cell walls occurring in plants under the impact of pathogens or herbivores can be mimicked by cell wall incision with a glass micropipette. Measurements of pH at the surface of Chara corallina internodes following microperforation of cell wall revealed a rapid (10–30s) localized alkalinization of the apoplast after a lag period of 10–20s. The pH increase induced by incision could be as large as 3 pH units and relaxed slowly, with a halftime up to 20min. The axial pH profile around the incision zone was bell-shaped and localized to a small area, extending over a distance of about 100μm. The pH response was suppressed by lowering cell turgor upon the replacement of artificial pond water (APW) with APW containing 50mM sorbitol. Stretching of the plasma membrane during its impression into the cell wall defect is likely to activate the Ca2+ channels, as evidenced from sensitivity of the incision-induced alkalinization to the external calcium concentration and to the addition of Ca2+-channel blockers, such as La3+, Gd3+, and Zn2+. The maximal pH values attained at the incision site (~10.0) were close to pH in light-dependent alkaline zones of Chara cells. The involvement of cytoskeleton in the origin of alkaline patch was documented by observations that the incision-induced pH transients were suppressed by the inhibitors of microtubules (oryzalin and taxol) and, to a lesser extent, by the actin inhibitor (cytochalasin B). The results indicate that the localized increase in apoplastic pH is an early event in mechanoperception and depends on light, cytoskeleton, and intracellular calcium

Volga-Ural Sandy Plague Focus Differentiation against Epizootic Manifestations by Means of Circular Extrapolation

Displayed are the results of study of the Volga-Ural sandy plague focus spatial structure. Constructed has been the map of the area with long-lasting persistent epizootic manifestations, monitored throughout the whole period from 1926 to 2012, using method of circular extrapolation of plague microbe detection points. Epizootic area mapping and map adjustment have been carried out automatically with the help of ArcGIS-10 software. The map displays the dislocation of plague focus activity nuclei and zones of short-term epizootic process registration; identified have been their quantitative parameters. Cartographic model of plague-focal territory differentiation against epizootic manifestation index is designed for validated planning of epidemiological surveillance activities and further studies of plague enzootics issues. The data obtained can be used for epidemiological zoning of territories as regards plague

Evaluation of elastic and adhesive properties of solids by depth-sensing indentation

To describe properly interactions between contacting solids at micro/nanometre scales, one needs to know both adhesive and mechanical properties of the solids. Borodich and Galanov have introduced an effective method (the BG method) for identifying both characteristics from a single experiment on depth-sensing indentation by a spherical indenter using optimal fitting of the experimental data. Unlike traditional indentation techniques involving sharp indenters, the Borodich-Galanov methodology intrinsically takes adhesion into account. It is essentially a non-destructive approach. These features extend the scope of the method to important applications beyond the capabilities of conventional indentation. The scope of the original BG method was limited to the classic JKR and DMT theories. Recently, this restriction has been overcome by introducing the extended BG (eBG) method, where a new objective functional based on the concept of orthogonal distance curve fitting has been introduced. In the present work, questions related to theoretical development of the eBG method are discussed. Using the data for elastic bulk samples, it is shown that the eBG method is at least as good as the original BG method. It is shown that the eBG can be applied to adhesive indentation of coated, multilayered, functionally graded media

Estimation of the elastic modulus and the work of adhesion of soft materials using the extended Borodich–Galanov (BG) method and depth sensing indentation

© 2018 Elsevier Ltd The depth-sensing indentation (DSI) is currently one of the main experimental techniques for studying elastic properties of materials of small volumes. Usually DSI tests are performed using sharp pyramidal indenters and the load-displacement curves obtained are used for estimations of elastic moduli of materials, while the curve analysis for these estimations is based on the assumptions of the Hertz contact theory of non-adhesive contact. The Borodich–Galanov (BG) method provides an alternative methodology for estimations of the elastic moduli along with estimations of the work of adhesion of the contacting pair in a single experiment using the experimental DSI data for spherical indenters. The method assumes fitting the experimental points of the load-displacement curves using a dimensionless expression of an appropriate theory of adhesive contact. Earlier numerical simulations showed that the BG method was robust. Here first the original BG method is modified and then its accuracy in the estimation of the reduced elastic modulus is directly tested by comparison with the results of conventional tensile tests. The method modification is twofold: (i) a two-stage fitting of the theoretical DSI dependency to the experimental data is used and (ii) a new objective functional is introduced which minimizes the squared norm of difference between the theoretical curve and the one used in preliminary data fitting. The direct experimental validation of accuracy and robustness of the BG method has two independent steps. First the material properties of polyvinyl siloxane (PVS) are determined from a DSI data by means of the modified BG method; and then the obtained results for the reduced elastic modulus are compared with the results of tensile tests on dumbbell specimens made of the same charge of PVS. Comparison of the results of the two experiments showed that the absolute minimum in relative difference between individual identified values of the reduced elastic modulus in the two experiments was 3.80%; the absolute maximum of the same quantity was 27.38%; the relative difference in averaged values of the reduced elastic modulus varied in the range 16.20.. 17.09% depending on particular settings used during preliminary fitting. Hence, the comparison of the results shows that the experimental values of the elastic modulus obtained by the tensile tests are in good agreement with the results of the extended BG method. Our analysis shows that unaccounted factors and phenomena tend to decrease the difference in the results of the two experiments. Thus, the robustness and accuracy of the proposed extension of the BG method has been directly validated

Определение оптимальных условий экстракции фурокумаринов из плодов амми большой

Extracting time and the multiplicity of extraction of furocoumarins from the fruits of Ammi majus were determined on the basis of experimental data, with the use of method of natural scales. The found conditions enable reducing the technological process time and labor, also reducing the consumption of the extraction agent.На основании экспериментальных данных, с использованием метода натуральных масштабов, определены экстрагент, время и кратность экстракции фурокумаринов из плодов амми большой. Подобранные условия позволяют сократить время технологического процесса, снизить расход экстрагента и трудозатраты

Antiviral Activity of Extracts from Basidiomycetes for Orthopoxviruses

Carried out was evaluation of the effect of water extracts from basidiomycetes in Vero cell culture on variola virus, and vaccinia virus. Antiviral effect demonstrated Inonotus obliquus (Chaga), befungin and melanin from chaga, Ganoderma applanatum (Artist’s Bracket) , Fomitopsis officinalis (Larch Fungus)

ОПТИМИЗАЦИЯ СИНТЕЗА 2'- О-α- D-РИБОФУРАНОЗИЛАДЕНОЗИНА ПО МЕТОДУ СИМПЛЕКСНОГО ПЛАНИРОВАНИЯ

Disaccharide nucleosides belong to an important group of natural compounds found in t-RNA and poly(ADPribose). They are also key elements in the structure of antibiotics and other physiologically active compounds. Poly(ADP-ribosylation) is a posttranslational modification of proteins in eukariotic cells catalyzed by poly(ADPribose)-polymerazes. The importance of poly(ADP-ribose) has been established in many cellular processes such as DNA replication, recombination and repair and cellular differentiation. The development of the synthesis of poly(ADP-ribose) and it’s components is still a challenging problem. The synthesis of 2'-O-α-D-ribofuranosyladenosine, a monomeric unit of poly(ADP-ribose) reported earlier has been improved. An important step on this way is the formation of a 2'-O-glycosidic bond between the adenosine and carbohydrate moieties. A new strategy involving glycosylation of 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)adenosine has been suggested. Varying of the catalyst (SnCl4), nucleoside and carbohydrate relations by the simplex method allowed improving the yields in the glycosylation step from 35 to 64%. As a result, it made possible to reach a higher overall yield of 2'-O-α-D-ribofuranosyladenosine in comparison with the literature data.С помощью метода симплексного планирования оптимизирован синтез 2'-O-α-D-рибофура-нозиладенозина - мономерного звена поли(АDP-рибозы). Подбор оптимальных соотношений катализатора (SnCl4), нуклеозида и углеводной компоненты позволил повысить выходы на стадии гликозилирования с 35 до 64%

Sensitivity of Different Animal Species to Monkeypox Virus

Studied is the sensitivity of different animal species (white mice, rabbits, mini-pigs, and marmots) to Monkeypox virus (MPXV). Determined is the fact that MPXV-sensitive are groundhogs (ID50 and LD50 5 lg of PFU in case of intranasal inoculation). The most pronounced clinical signs of the disease such as varioliform eruption all over body and mucous linings, purulent discharges out of nasal cavity, lymphadenitis, loss of coordination, tremor of extremities, fever, hyper-aggressiveness, disheveled hair have been registered in groundhogs. The highest viral loads in the majority of fallen marmots have been observed in nasal mucosa, trachea, lungs, and pock-marked skin (>6,0 lg PFU/g). The symptomatology of the disease in mice as compared to groundhogs is a bit milder: purulent conjunctivitis, blepharitis, and disheveled hair. As for mini-pigs and rabbits, no visual signs of the disease have been observed in them

Модификация дисперсных систем полимерами при механическом воздействии

The processes of surface modification in aqueous dispersions of hydrophilic inorganic pigments (titanium dioxide, ferrous oxide) as well as hydrophobic organic pigments (copper phthalocyanine and carbon black) by polymers of various nature were reviewed. The pigment surface modification by these polymers was achieved by conventional adsorption as well as by mechanical (ultrasonic and vibrowave) treatment of the pigment dispersion. The efficiency of the pigment surface coating was followed by the IR-analysis, Electrokinetic Sonic Amplitude (ESA) method and transmission electronic microscopy that enabled to gain quantitative data about the thickness and structure of polymer adsorption layers. Ultrasonic and vibrowave techniques have been shown to provide significant improvement of polymer adsorption layer thickness and to be a promising way for the surface modification of pigments with regard to their dispersion stability. Thermo-responsive («smart») polymers were shown to be effective temperature-controlled modifiers for both hydrophobic and hydrophilic pigmentsВ статье обсуждены результаты систематических исследований дисперсности водных суспензий ор- ганических и неорганических пигментов. Установлено, что с помощью механиче- ского воздействия в присутствии по- верхностно-активных полимеров можно существенно повысить их стабильность, дисперсность и качество. С помощью методов ИК-спектроскопии, проникающей электронной микроскопии, электрокине- тической звуковой амплитуды оценены свойства суспензий органических и не- органических пигментов, полученных в присутствии поверхностно-активных полимеров различной природы, вычисле- ны толщины полимерных адсорбционных слоев и определена их структура. Пока- зана перспективность использования температурно- чувствительных (“smart”) полимеров для модификации поверхности как гидрофильных, так и гидрофобных пигментов