Study of the Possible Involvement of Azospirillum Lectins in the Mechanisms of Adaptive Response of Plants Exposed to Heavy Metal Salts

Azospirillum, which has the potential to stimulate plant growth, belongs to plant-growthpromoting bacteria. The lectin found on its surface can bind specific carbohydrates and ensures adhesion of the bacteria to the root surface. We examined the effect of the lectins from two strains – A. brasilense Sp7 (epiphytic strain) and A. brasilense Sp245 (endophytic strain) – on the activities of antioxidant enzymes in roots of 4-day-old seedlings of wheat exposed to heavy metals (CoSO4, ZnSO4, Pb(CH3COO)2 and CuSO4). Under all stresses, both lectins increased peroxidase and superoxide dismutase activities and decreased catalase activity, but the periods of effect and the concentrations involved were different. These differences may have been caused by the different structures and carbohydrate specificities of the lectins, which resulted in differences in the interaction with the plant cell surface such differences are of deciding importance for the “switch on” of the subsequent stages. Azospirillum lectins are involved in adaptational changes in wheat seedling roots. This involvement promotes the normal course of metabolism and ensures regulation of the plant–Azospirillum interaction in a wide range of soil and climatic factors

The Kharkov X-ray Generator Facility NESTOR

WEPWA060 - ISBN 978-3-95450-122-9International audienceThe last few years the sources of the X-rays NESTOR based on a storage ring with low beam energy and Compton scattering of intense laser beam are under design and development in NSC KIPT. The main task of the project is to develop compact intense X-ray generator on the base of relatively cheap accelerator equipment and up-to-date laser technologies. The paper is devoted to description of the last results on construction and commissioning of the facility

Plant Cell Protolytic Enzymes Activity under Exposure to Lectins of Endophytic and Epiphytic Azospirillum Strains

We studied the ability of lectins isolated from the surface of the two strains of nitrogen-fixing soil bacteria of the genus Azospirillum, A. brasilense Sp7 (epiphytic) and A. brasilense Sp245 (endophytic), to show have a regulating effect on the activity of pectinolytic enzymes in the roots of wheat seedlings. Research results showed that the lectins under study can cause the induction of the activity of polygalacturonase, pectinesterase, pectatlyase from the plant cell wall, thereby ensuring the bacteria penetration in the plant tissues, as well as the induction of plants responses which, being combined with growth-stimulating effect of bacteria, contributes to the formation of plants stability and productivity

Azospirillum lectin – induced changes in the content of nitric oxide in wheat seedling roots

The lectin of Azospirillum brasilense Sp7 at 40 μg ml-1 elicited two peaks of induction of nitric oxide synthesis in the roots of wheat seedlings after 3 and 26 h of coincubation. The lectin of A. brasilense Sp7.2.3, a mutant defective in lectin activity, produced the same effect, but the activation of nitric oxide synthesis in the roots was less in the case of 26-h incubation. Exposure to the lectins for 3 h increased citrulline synthesis in the plant cell to the same extent. This finding indicated that the Azospirillum lectins activate nitric oxide production through the NO signal system of plants, thereby acting as inducers of adaptation processes in the roots of wheat seedlings

Effect of Cold Stress on Fruiting Body Production by Medicinal Basidiomycetes in Submerged and Solid-phase Culture

The ability of the medicinal xylotrophic basidiomycetes Lentinus edodes, Pleurotus ostreatus, Ganoderma lucidum and Grifola frondosa to produce typical and atypical fruiting bodies with viable basidiospores in submerged and solid-phase culture under stationary conditions in a beer wort-containing medium under cold stress was shown. The examined mushrooms, when not exposed to temperature stress, did not form fruiting bodies. In solid-phase culture in an agarized medium after cold treatment, the basidiome formation period was shortened by 1.5–2 times. Furthermore, the use of a mycelium subjected to temperature stress for inoculation induced and accelerated the formation of fruiting bodies on an industrial wood substrate, which is of great biotechnological importance

The sulfur isotope effect on the Peierls transition temperature in o-TaS3

The Peierls conductor o-TaS3 enriched with isotope (34S (99%)) has been synthesized. The temperature and electric field dependencies of the conduction of these samples were studied. The results were compared with ones for samples of the same quality with natural isotope composition. The following parameters of the linear conduction were extracted : the Peierls transition temperature (Tp), the width (δTp) and height of the peak of temperature derivative of conduction, activation energy (Δ). Small increase of the Peierls transition temperature by 1 ± 1 K was observed in Ta34S3 samples