2,4,6-trinitrotoluene as a trigger of oxidative stress in Fagopyrum tataricum callus cells

Effect of 2,4,6-trinitrotoluene (TNT) on callus cells of Tartar buckwheat (Fagopyrum tataricum (L.) Gaertn.) was accompanied by six-electron reduction of ortho- or para-nitro groups of the xenobiotic with the production of 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT). It was discovered that the xenobiotic TNT impairs integrity of cell membrane, which apparently results from its one-electron reduction coupled with production of nitro radical-anion and superoxide anion. © 2013 Pleiades Publishing, Ltd

Morphometric characterization of fibrinogen's αc regions and their role in fibrin self-assembly and molecular organization

© 2017 The Royal Society of Chemistry. The flexible C-terminal parts of fibrinogen's Aα chains named the αC regions have been shown to play a role in fibrin self-assembly, although many aspects of their structure and functions remain unknown. To examine the involvement of the αC regions in the early stages of fibrin formation, we used high-resolution atomic force microscopy to image fibrinogen and oligomeric fibrin. Plasma-purified full-length human fibrinogen or des-αC fibrinogen lacking most of the αC regions, untreated or treated with thrombin, was imaged. Up to 80% of the potentially existing αC regions were visualized and quantified; they were highly heterogeneous in their length and configurations. Conversion of fibrinogen to fibrin was accompanied by an increase in the incidence and length of the αC regions as well as transitions from more compact conformations, such as a globule on a string, to extended and more flexible offshoots. Concurrent dynamic turbidimetry, confocal microscopy, and scanning electron microscopy revealed that trimming of the αC regions slowed down fibrin formation, which correlated with longer protofibrils, thinner fibers, and a denser network. No structural distinctions, except for the incidence of the αC regions, were revealed in the laterally aggregated protofibrils made of the full-length or des-αC fibrinogens, suggesting a pure kinetic effect of the αC regions on the fibrin architecture. This work provides a structural molecular basis for the promoting role of the αC regions in the early stages of fibrin self-assembly and reveals this stage of fibrin formation as a potential therapeutic target to modulate the structure and mechanical properties of blood clots

Single-Molecule Interactions of a Monoclonal Anti-DNA Antibody with DNA

© 2016, Springer Science+Business Media New York.Interactions of DNA with proteins are essential for key biological processes and have both a fundamental and practical significance. In particular, DNA binding to anti-DNA antibodies is a pathogenic mechanism in autoimmune pathology, such as systemic lupus erythematosus. Here we measured at the single-molecule level binding and forced unbinding of surface-attached DNA and a monoclonal anti-DNA antibody MRL4 from a lupus erythematosus mouse. In optical trap-based force spectroscopy, a microscopic antibody-coated latex bead is trapped by a focused laser beam and repeatedly brought into contact with a DNA-coated surface. After careful discrimination of non-specific interactions, we showed that the DNA-antibody rupture force spectra had two regimes, reflecting formation of weaker (20–40 pN) and stronger (>40 pN) immune complexes that implies the existence of at least two bound states with different mechanical stability. The two-dimensional force-free off-rate for the DNA-antibody complexes was ∼2.2 × 10−3 s−1, the transition state distance was ∼0.94 nm, the apparent on-rate was ∼5.26 s−1, and the stiffness of the DNA-antibody complex was characterized by a spring constant of 0.0021 pN/nm, suggesting that the DNA-antibody complex is a relatively stable, but soft and deformable macromolecular structure. The stretching elasticity of the DNA molecules was characteristic of single-stranded DNA, suggesting preferential binding of the MRL4 antibody to one strand of DNA. Collectively, the results provide fundamental characteristics of formation and forced dissociation of DNA-antibody complexes that help to understand principles of DNA-protein interactions and shed light on the molecular basis of autoimmune diseases accompanied by formation of anti-DNA antibodies

Shape changes of erythrocytes during blood clot contraction and the structure of polyhedrocytes

© 2018, The Author(s). Polyhedral erythrocytes, named polyhedrocytes, are formed in contracted blood clots and thrombi, as a result of compression by activated contractile platelets pulling on fibrin. This deformation was shown to be mechanical in nature and polyhedrocytes were characterized using light and electron microscopy. Through three-dimensional reconstruction, we quantified the geometry of biconcave, intermediate, and polyhedral erythrocytes within contracting blood clots. During compression, erythrocytes became less oblate and more prolate than the biconcave cells and largely corresponded to convex, irregular polyhedra with a total number of faces ranging from 10 to 16. Faces were polygons with 3 to 6 sides. The majority of the faces were quadrilaterals, though not all sides were straight and not all faces were flat. There were no changes in the surface area or volume. These results describe the gradual natural deformation of erythrocytes as a part of compaction into a tightly packed array that is an important but understudied component of mature blood clots and thrombi

THE PRESENT CONDITION AND PROSPECTS OF MILLET SEED-GROWING IN THE ORENBURG REGION

The article has presented the analysis of varietal sowings in the Orenburg region during 2009-2013. It has estimated the change of a share of varietal and row sowings of millet. The analysis of the areas of various categories of millet sowings has determined a range of the share of varietal and row sowing on the general area, which was connected with availability of basic varietal seed material. During the 5-year period the share of varietal sowings ranged between 64.1-72.9 %. The article has given a volume of original and basic sowing material production in FSBSI “Orenburg RIA” and FSTI “Sovetskaya Rossiya”. Each year from 2400 to 3500 species of millet are subject to selection and culling. This amount of selected varieties provides the production of basic seed of Orenburg breeding with sufficient amounts. The assessment of categories of used seed material on the parts of the Orenburg region has been given. In the Orenburg region the sowing material of millet is presented with 0.4 th. htw of original seeds (3.5% of the whole amount of sown seeds), 0.3 th. htw of basic seeds (2.7%), 0,2 th. htw of seeds of the 1-st reproduction (1.8%), 0,1 th. htw of seeds of the 2-nd reproduction (0.9%), 1.3 th. htw of seeds of the 3-d reproduction (11.5%) and 5.1 th. htw of seeds of the mass reproduction (45.1%). It is necessary to increase the areas of varietal sowings of millet and to improve quality of sowing material for more efficient grain production

Resilient living materials built by printing bacterial spores

Materials can be made multifunctional by embedding them with living cells that perform sensing, synthesis, energy production, and physical movement. A challenge is that the conditions needed for living cells are not conducive to materials processing and require continuous water and nutrients. Here, we present a three dimensional (3D) printer that can mix material and cell streams to build 3D objects. Bacillus subtilis spores were printed within the material and germinated on its exterior surface, including spontaneously in new cracks. The material was resilient to extreme stresses, including desiccation, solvents, osmolarity, pH, ultraviolet light, and γ-radiation. Genetic engineering enabled the bacteria to respond to stimuli or produce chemicals on demand. As a demonstration, we printed custom-shaped hydrogels containing bacteria that can sense or kill Staphylococcus aureus, a causative agent of infections. This work demonstrates materials endued with living functions that can be used in applications that require storage or exposure to environmental stresses.Office of Naval Research (Grant N00014-16-1-2509

2,4,6-trinitrotoluene as a trigger of oxidative stress in Fagopyrum tataricum callus cells

Effect of 2,4,6-trinitrotoluene (TNT) on callus cells of Tartar buckwheat (Fagopyrum tataricum (L.) Gaertn.) was accompanied by six-electron reduction of ortho- or para-nitro groups of the xenobiotic with the production of 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT). It was discovered that the xenobiotic TNT impairs integrity of cell membrane, which apparently results from its one-electron reduction coupled with production of nitro radical-anion and superoxide anion. © 2013 Pleiades Publishing, Ltd

2,4,6-trinitrotoluene as a trigger of oxidative stress in Fagopyrum tataricum callus cells

Effect of 2,4,6-trinitrotoluene (TNT) on callus cells of Tartar buckwheat (Fagopyrum tataricum (L.) Gaertn.) was accompanied by six-electron reduction of ortho- or para-nitro groups of the xenobiotic with the production of 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT). It was discovered that the xenobiotic TNT impairs integrity of cell membrane, which apparently results from its one-electron reduction coupled with production of nitro radical-anion and superoxide anion. © 2013 Pleiades Publishing, Ltd

2,4,6-trinitrotoluene as a trigger of oxidative stress in Fagopyrum tataricum callus cells

Effect of 2,4,6-trinitrotoluene (TNT) on callus cells of Tartar buckwheat (Fagopyrum tataricum (L.) Gaertn.) was accompanied by six-electron reduction of ortho- or para-nitro groups of the xenobiotic with the production of 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT). It was discovered that the xenobiotic TNT impairs integrity of cell membrane, which apparently results from its one-electron reduction coupled with production of nitro radical-anion and superoxide anion. © 2013 Pleiades Publishing, Ltd

Structural Basis of Interfacial Flexibility in Fibrin Oligomers

© 2016 Elsevier LtdFibrin is a filamentous network made in blood to stem bleeding; it forms when fibrinogen is converted into fibrin monomers that self-associate into oligomers and then to polymers. To gather structural insights into fibrin formation and properties, we combined high-resolution atomic force microscopy of fibrin(ogen) oligomers and molecular modeling of crystal structures of fibrin(ogen) and its fragments. We provided a structural basis for the intermolecular flexibility of single-stranded fibrin(ogen) oligomers and identified a hinge region at the D:D inter-monomer junction. Following computational reconstruction of the missing portions, we recreated the full-atomic structure of double-stranded fibrin oligomers that was validated by quantitative comparison with the experimental images. We characterized previously unknown intermolecular binding contacts at the D:D and D:E:D interfaces, which drive oligomerization and reinforce the intra- and inter-strand connections in fibrin besides the known knob-hole bonds. The atomic models provide valuable insights into the submolecular mechanisms of fibrin polymerization