Taxonomy of the order Bunyavirales : second update 2018

In October 2018, the order Bunyavirales was amended by inclusion of the family Arenaviridae, abolishment of three families, creation of three new families, 19 new genera, and 14 new species, and renaming of three genera and 22 species. This article presents the updated taxonomy of the order Bunyavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).Non peer reviewe

Photochemistry of Fe(III) and sulfosalicylic acid aqueous solutions

Femtosecond and nanosecond laser flash photolysis was used to determine the photophysical and photochemical processes in aqueous solutions of Fe(III) ion and 5-sulfosalicylic acid (SSA) containing the FeSSA complex and the free ligand. Excitation of the FeSSA complex in the charge transfer band (λmax = 505 nm) is followed by an ultrafast relaxation to the ground electronic state with two characteristic times of 0.26 and 1.8 ps. The shorter time constant is ascribed to internal conversion to the vibrationally hot electronic ground state of FeSSA and the 1.8 ps time constant is assigned to the vibrational cooling of the ground state. The UV irradiation of the solution (308 nm) leads to the excitation of both the free ligand and the FeSSA complex. The latter relaxes rapidly and the free ligand undergoes intersystem crossing to the triplet state. This system undergoes an irreversible photochemical reaction originating from an electron transfer (k = (9 ± 2) × 108 M−1 s−1) from the free ligand in the triplet state to the FeSSA complex. This electron transfer is accompanied by an energy transfer between these species (k = (1.3 ± 0.2) × 109 M−1 s−1)

Photochemistry of Dithiocarbamate Cu(S₂CNEt₂)₂ Complex in CHCl₃. Transient Species and TD-DFT Calculations

Nanosecond laser flash photolysis was used to study the mechanism of photochemical transformations of the diethyldithiocarbamate Cu­(II) complex (Cu­(dtc)₂, where dtc^– ≡ ^–S₂CNEt₂ anion) in chloroform solutions. The electron transfer from the excited Cu­(dtc)₂ complex to a solvent molecule leads to the appearance of the primary intermediate, the [ClCu­(dtc)­(dtcCHCl₂)] complex, where a dtcCHCl₂ molecule is coordinated with a copper ion via one sulfur atom. In the fast reaction (<i>k</i> = 2.1 × 10⁹ M^–1 s^–1) with Cu­(dtc)₂, this complex forms a long-lived dimer [ClCu­(dtc)­(dtcCHCl₂)­Cu­(dtc)₂]. This intermediate decays during several seconds (<i>k</i> = 5.6 × 10^–2 s^–1) into the final product, i.e., a diamagnetic dimer [ClCu­(dtc)­Cu­(dtc)₂]. To determine the structure of intermediate complexes the quantum chemical calculations were carried out using DFT, TD-DFT, and PCM (Polarizable Continuum Model) methods

Photoinduced Processes in Lysine-Tryptophan-Lysine Tripeptide with L and D Tryptophan

Optical isomers of short peptide Lysine-Tryptophan-Lysine (Lys-{L/D-Trp}-Lys) and Lys-Trp-Lys with an acetate counter-ion were used to study photoinduced intramolecular and intermolecular processes of interest in photobiology. A comparison of L- and D-amino acid reactivity is also the focus of scientists’ attention in various specialties because today, the presence of amyloid proteins with D-amino acids in the human brain is considered one of the leading causes of Alzheimer’s disease. Since aggregated amyloids, mainly Aβ42, are highly disordered peptides that cannot be studied with traditional NMR and X-ray techniques, it is trending to explore the reasons for differences between L- and D-amino acids using short peptides, as in our article. Using NMR, chemically induced dynamic nuclear polarization (CIDNP) and fluorescence techniques allowed us to detect the influence of tryptophan (Trp) optical configuration on the peptides fluorescence quantum yields, bimolecular quenching rates of Trp excited state, and the photocleavage products formation. Thus, compared with the D-analog, the L-isomer shows a greater Trp excited state quenching efficiency with the electron transfer (ET) mechanism. There are experimental confirmations of the hypothesis about photoinduced ET between Trp and the CONH peptide bond, as well as between Trp and another amide group