Functional Coatings Based on Hydroxyapatite and Polymers Formed on Ti-6Al-4V Substrates

The paper describes perspective technology for deposition of inorganic-organic coatings used for biomedical application. Synthetic hydroxyapatite was used as inorganic compound, due to the similarity of the main component to bone tissue. As organic components we used chitosan and alginate – natural biopolymers, which widely used for bioactive and biocompatible composites formation. Thermal substrate method used for coatings deposition based on principle of decreasing solubility of hydroxyapatite with increasing of substrate temperature and allow to deposit coatings at substrate temperatures below 100 °C. Porous composite hydroxyapatite-chitosan and hydroxyapatite-alginate coatings were obtained on Ti-6Al-4V substrates. Morphology, phase composition and adhesion to the substrate surface were investigated. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3529

Efficiency of RNA Hydrolysis by Binase from Bacillus pumilus: The Impact of Substrate Structure, Metal Ions, and Low Molecular Weight Nucleotide Compounds

Binase is an extracellular guanyl-preferring ribonuclease from Bacillus pumilus. The main biological function of binase is RNA degradation with the formation of guanosine-2',3'-cyclic phosphate and its subsequent hydrolysis to 3'-phosphate. Extracellular RNases are believed to be key agents that affect the functional activity of the body, as they directly interact with epithelial and immune cells. The biological effects of the enzyme may consist of both direct RNA degradation, and the accumulation of 2',3'-cGMP in the human body. In this work, we have performed a comparative analysis of the cleavage efficiency of model RNA substrates, i.e., short hairpin structures that contain guanosine at various positions. It has been shown that the hydrolysis efficiency of the model RNA substrates depends on the position of guanosine. We have also demonstrated the influence of various divalent metal ions and low molecular weight nucleotide compounds on the binase-catalyzed endoribonucleolytic reaction

Efficiency of RNA Hydrolysis by Binase from Bacillus pumilus: The Impact of Substrate Structure, Metal Ions, and Low Molecular Weight Nucleotide Compounds

© 2020, Pleiades Publishing, Inc. Abstract: Binase is an extracellular guanyl-preferring ribonuclease from Bacillus pumilus. The main biological function of binase is RNA degradation with the formation of guanosine-2',3'-cyclic phosphate and its subsequent hydrolysis to 3'-phosphate. Extracellular RNases are believed to be key agents that affect the functional activity of the body, as they directly interact with epithelial and immune cells. The biological effects of the enzyme may consist of both direct RNA degradation, and the accumulation of 2',3'-cGMP in the human body. In this work, we have performed a comparative analysis of the cleavage efficiency of model RNA substrates, i.e., short hairpin structures that contain guanosine at various positions. It has been shown that the hydrolysis efficiency of the model RNA substrates depends on the position of guanosine. We have also demonstrated the influence of various divalent metal ions and low molecular weight nucleotide compounds on the binase-catalyzed endoribonucleolytic reaction

Pre-illumination of rice blast conidia induces tolerance to subsequent oxidative stress

Many environmental factors, alone or combined, affect organisms by changing a pro-/antioxidant balance. Here we tested rice blast fungus (Magnaporthe oryzae) for possible cross-adaptations caused by relatively intense light and protecting from artificially formed reactive oxygen species (ROS) and ROS-dependent fungitoxic response of the host plant. Spore germination was found to be suppressed under 4-hand, to larger extent, 5-hillumination. The effect was diminished by antioxidants and, therefore, suggests involvement of ROS. One-hour of light did not affect spore germination, but stimulated their chemically assayed superoxide production. The illuminated spores were more tolerant (than non-illuminated ones) to artificially generated H2O2, O2 -, or OH or to toxic diffusate of rice leaf. They also caused more severe disease symptoms if applied to leaves of the susceptible rice cultivar at low concentration. Spore diffusates decomposed hydrogen peroxide. They detoxified exogenous H2O2 and superoxide radical as well as leaf diffusates. Spore illumination increased some of these protective effects. It is suggested that short-term light led to mild oxidative stress, which induced spore antioxidant capacity, enhancing spore tolerance to subsequent stronger oxidative stress and its aggressiveness in planta. Such tolerance depends partly on the antidotal action of spore extracellular compounds, which may also be light-stimulated. Therefore, a certain ROS-related environmental factor may adapt a fungus to other factors and so modulate its pathogenic properties. © 2014 The British Mycological Society

Reaction of indolizines with elemental sulfur

The fusion of 3,8-diphenyl-, 1,2-diphenyl-, and 6-methyl-2,7-diphenyl-indolizines with sulfur results in the formation of bis(indolizin-3-yl) disulfides with the respective substituents. Bis(2,8-diphenylindolizin-3-yl) disulfide is reduced to the original indolizine, and its treatment with nitric acid gives 2,8-diphenyl-1, 3-dinitroindolizine. Bis(dibenzo[b,g]indolizin-11-yl) disulfide is obtained from dibenzo[b,g]indolizine. The formation of the disulfides is apparently a general region of indolizines without substituents at C3 or C1 of the pyrrole ring. The structures of the disulfides obtained have been confirmed by data from x-ray diffraction analysis and NMR spectroscopy. © 1985 Plenum Publishing Corporation

Reaction of indolizines with elemental sulfur

The fusion of 3,8-diphenyl-, 1,2-diphenyl-, and 6-methyl-2,7-diphenyl-indolizines with sulfur results in the formation of bis(indolizin-3-yl) disulfides with the respective substituents. Bis(2,8-diphenylindolizin-3-yl) disulfide is reduced to the original indolizine, and its treatment with nitric acid gives 2,8-diphenyl-1, 3-dinitroindolizine. Bis(dibenzo[b,g]indolizin-11-yl) disulfide is obtained from dibenzo[b,g]indolizine. The formation of the disulfides is apparently a general region of indolizines without substituents at C3 or C1 of the pyrrole ring. The structures of the disulfides obtained have been confirmed by data from x-ray diffraction analysis and NMR spectroscopy. © 1985 Plenum Publishing Corporation