Electron and nuclear dynamics in many-electron atoms, molecules and chlorophyll-protein complexes: A review

It has been shown [V.A. Shuvalov, Quantum dynamics of electrons in many-electron atoms of biologically important compounds, Biochemistry (Mosc.) 68 (2003) 1333-1354; V.A. Shuvalov, Quantum dynamics of electrons in atoms of biologically important molecules, Uspekhi biologicheskoi khimii, (Pushchino) 44 (2004) 79-108] that the orbit angular momentum L of each electron in many-electron atoms is L = mVr = n? and similar to L for one-electron atom suggested by N. Bohr. It has been found that for an atom with N electrons the total electron energy equation E = −(Z^eff)²e⁴m/(2n²?²N) is more appropriate for energy calculation than standard quantum mechanical expressions. It means that the value of L of each electron is independent of the presence of other electrons in an atom and correlates well to the properties of virtual photons emitted by the nucleus and creating a trap for electrons. The energies for elements of the 1st up to the 5th rows and their ions (total amount 240) of Mendeleev' Periodical table were calculated consistent with the experimental data (deviations in average were 5 × 10^− 3). The obtained equations can be used for electron dynamics calculations in molecules. For H₂ and H₂⁺ the interference of electron-photon orbits between the atoms determines the distances between the nuclei which are in agreement with the experimental values. The formation of resonance electron-photon orbit in molecules with the conjugated bonds, including chlorophyll-like molecules, appears to form a resonance trap for an electron with E values close to experimental data. Two mechanisms were suggested for non-barrier primary charge separation in reaction centers (RCs) of photosynthetic bacteria and green plants by using the idea of electron-photon orbit interference between the two molecules. Both mechanisms are connected to formation of the exciplexes of chlorophyll-like molecules. The first one includes some nuclear motion before exciplex formation, the second one is related to the optical transition to a charge transfer state.     

Oxidative addition of 3,6-di-tert-butyl-o-benzoquinone and 4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-iminobenzoquinone to SnCl2

Addition of 3,6-di-tert-butyl-o-benzoquinone (3,6-DBBQ) to SnCl₂ in THF leads to the oxidation of Sn(II) to Sn(IV) with formation of catecholate complex (3,6-DBCat)SnCl₂ · 2THF (1), where 3,6-DBCat is 3,6-di-tert-butyl-catecholate dianion. The reaction of 4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-iminobenzoquinone (IBQ-Prⁱ) also proceeds on the oxidative-addition mechanism yielding bis-iminosemiquinonato species (ISQ-Prⁱ)₂SnCl₂(2), where ISQ-Prⁱ is anion-radical 4,6-di-tert-butyl-N-(2,6-di-iso-propylphenyl)-o-iminobenzosemiquinolate. The complexes have been characterized by IR, X-band EPR, ¹H NMR (for 1) spectroscopy and magnetochemistry (for 2). X-ray analysis data show the distorted octahedral environment of tin(IV) for both complexes. Complex 1 is diamagnetic (ground state S = 0), while 2 has triplet ground state (S = 1, biradical). Catecholate complex 1 is able to be a spin trap for different organic radicals.     

Versatile High Resolution Oligosaccharide Microarrays for Plant Glycobiology and Cell Wall Research

Microarrays are powerful tools for high throughput analysis, and hundreds or thousands of molecular interactions can be assessed simultaneously using very small amounts of analytes. Nucleotide microarrays are well established in plant research, but carbohydrate microarrays are much less established, and one reason for this is a lack of suitable glycans with which to populate arrays. Polysaccharide microarrays are relatively easy to produce because of the ease of immobilizing large polymers noncovalently onto a variety of microarray surfaces, but they lack analytical resolution because polysaccharides often contain multiple distinct carbohydrate substructures. Microarrays of defined oligosaccharides potentially overcome this problem but are harder to produce because oligosaccharides usually require coupling prior to immobilization. We have assembled a library of well characterized plant oligosaccharides produced either by partial hydrolysis from polysaccharides or by de novo chemical synthesis. Once coupled to protein, these neoglycoconjugates are versatile reagents that can be printed as microarrays onto a variety of slide types and membranes. We show that these microarrays are suitable for the high throughput characterization of the recognition capabilities of monoclonal antibodies, carbohydrate-binding modules, and other oligosaccharide-binding proteins of biological significance and also that they have potential for the characterization of carbohydrate-active enzymes.     

96 Study of the stacking of DNA homoassociates by the extended cluster approach

Metropolis Monte Carlo method based on the extended cluster approach (Danilov, Dailidonis, van Mourik, & Fruchtl, 2011a, 2011b; Dailidonis, Danilov, Früchtl, & van Mourik, 2011) is used to investigate adenine–adenine (AA), guanine–guanine (GG), thymine–thymine (TT), and cytosine–cytosine (CC) homoassociates in a cluster consisting of 400 water molecules. The starting structures taken were AA N(7) amino symmetric, TT N(3) – O(4) symmetric, GG N(1) – O(6) symmetric, and CC N(3) amino symmetric base pairs. A water spherical cluster with the density of water at room temperature and a radius sphere equal 13.9 Å was used, which corresponds to the most difficult conditions for the formation of stacks (see Abraham, 1982). In spite of such initial conditions, it is shown that during the simulation, each base pair is transformed into a more favorable stacked configuration. The results obtained allow to observe the whole process of convergence for the first time (for more information, visit the Website http://biophys.in.ua/).     

Cutting Edge: Differential inhibition of TLR signaling pathways by cell-permeable peptides representing BB loops of TLRs

We designed cell-penetrating peptides comprised of the translocating segment of Drosophila antennapedia homeodomain fused with BB loop sequences of TLR2, TLR4, and TLR1/6. TLR2- and TLR4-BB peptides (BBPs) inhibited NF-kappaB translocation and early IL-1beta mRNA expression induced by LPS, and the lipopeptides S-[2,3-bis(palmitoyloxy)-(2-RS)-propyl]-N-palmitoyl-(R)-Cys-Ser-Lys(4)-OH (P3C) and S-[2,3-bis(palmitoyloxy)-(2-RS)-propyl]-Cys-Ser-Lys(4)-OH (P2C). TLR4- and TLR2-BBPs also strongly inhibited LPS-induced activation of ERK. Only TLR2-BBP significantly inhibited ERK activation induced by P3C, which acts via TLR2/1 heterodimers. BBPs did not inhibit activation of ERK induced by P2C, a TLR2/6 agonist. The TLR2-BBP induced weak activation of p38, but not ERK or cytokine mRNA. The TLR1/6-BBP failed to inhibit NF-kappaB or MAPK activation induced by any agonist. Our results suggest that the receptor BBPs selectively affect different TLR signaling pathways, and that the BB loops of TLR1/6 and TLR2 play distinct roles in formation of receptor heterodimers and recruitment of adaptor proteins.     

Physical activity and exercise as an essential medical strategy for the COVID-19 pandemic and beyond

COVID-19 disease has been a problem in today’s society, which has worldwide effects on different areas, especially on the economy; also, from a health perspective, the disease affects the daily life quality. Physical activity is one major positive factor with regard to enhancing life quality, as it can improve the whole psychological, social, and physical health conditions. Current measures such as social distancing are focused on preventing the viral spread. However, the consequences on other areas are yet to be investigated. Elderly, people with chronic diseases, obese, and others benefit largely from exercise from the perspective of improved health, and preventive measures can drastically improve daily living. In this article, we elaborate the effects of exercise on the immune system and the possible strategies that can be implemented toward greater preventive potential.     

Poly(vinyl amine)-silica composite nanoparticles: models of the silicic acid cytoplasmic pool and as a silica precursor for composite materials formation

The role of polymer (poly(vinylamine)) size (238-11000 units) on silicic acid condensation to yield soluble nanoparticles or composite precipitates has been explored by a combination of light scattering (static and dynamic), laser ablation combined with aerosol spectrometry, IR spectroscopy, and electron microscopy. Soluble nanoparticles or composite precipitates are formed according to the degree of polymerization of the organic polymer and pH. Nanoparticles prepared in the presence of the highest molecular weight polymers have core-shell like structures with dense silica cores. Composite particles formed in the presence of polymers with extent of polymerization below 1000 consist of associates of several polymer-silica nanoparticles. The mechanism of stabilization of the "soluble" silica particles in the tens of nanometer size range involves cooperative interactions with the polymer chains which varies according to chain length and pH. An example of the use of such polymer-poly(silicic acid) nanoparticles in the generation of composite polymeric materials is presented. The results obtained have relevance to the biomimetic design of new composite materials based on silica and polymers and to increasing our understanding of how silica may be manipulated (stored) in the biological environment prior to the formation of stable mineralized structures. We suspect that a similar method of storing silicic acid in an active state is used in silicifying organisms, at least in diatom algae.     

<Emphasis Type="Italic">Bracon (Lucobracon) iskilipus</Emphasis> sp. n. (Hymenoptera: Braconidae: Braconinae) from the Central Black Sea region of Turkey

During the studies on the Turkish Braconidae, a new species Bracon (Lucobracon) iskilipus sp. n. from the Turkish Central Black Sea region was recorded. Bracon (Lucobracon) iskilipus sp. n. was described, its morphological diagnostic characters were illustrated and it was compared with the related Bracon (Lucobracon) moczari Papp.