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Complex (dusty) plasmas of micron-sized CeO2 polydisperse particles in dc glow discharges at 77 and ∼ 10 K were experimentally investigated. It was obtained that dust structure in cryogenic gas discharge plasma can be a mixture of two fractions (components) with completely different dust ordering and dynamics. We observed under some specific conditions that fast-moving particles of one component diffuse through another component consisted of dust particles arranged in linear chains (strings). From experimental data analysis particle velocity distribution functions for each dust component were obtained. The possible nature of two-component dust structure formation was discussed. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Molybdenum- and molybdenum cofactor-free nitrate reductases recently isolated by us from vanadate-reducing bacteria Pseudomonas isachenkovii are likely to mediate vanadate reduction. During anaerobic growth of P. isachenkovii on medium supplemented with nitrate and vanadate, vanadate dissimilation was followed by nitrate consumption, and this process was associated with some structural reorganizations of nitrate reductases. The homogeneous membrane-bound nitrate reductase of P. isachenkovii reduced vanadate with NADH as an electron donor. [ABSTRACT FROM AUTHOR]

A vanadium-binding protein was isolated from the culture medium of the vanadium-reducing bacterium Pseudomonas isachenkovii by utilizing vanadate as the terminal electron acceptor upon anaerobic respiration. The protein was associated with vanadium at a molar ratio of approximately 1:20. It was purified to homogeneity and separated into three components by treatment with 1 M HCl followed by gel filtration: a protein, a vanadium-binding ligand, and inorganic vanadium. Electron paramagnetic resonance analysis showed that vanadium was associated with the protein in the 4+ oxidation state. The distribution of vanadium within the cell was studied by electron microscopy and x-ray microanalysis of P. isachenkovii cells. The results suggest that vanadium, accumulated in special swells on the surface of the cell membranes, is reduced and excreted to the medium. [ABSTRACT FROM AUTHOR]

A novel cytochrome c nitrite reductase (TvNiR) was isolated from the haloalkalophilic bacterium Thioalkalivibrio nitratireducens. The enzyme catalyses nitrite and hydroxylamine reduction, with ammonia as the only product of both reactions. It consists of 525 amino-acid residues and contains eight haems c. TvNiR crystals were grown by the hanging-drop vapour-diffusion technique. The crystals display cubic symmetry and belong to space group P213, with unit-cell parameter a = 194 Å. A native data set was obtained to 1.5 Å resolution. The structure was solved by the SAD technique using the data collected at the Fe absorption peak wavelength. [ABSTRACT FROM AUTHOR]