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Luminous marine bacteria are traditionally used as a bioassay due to the convenience and high rate of registering the intensity of their physiological function - luminescence. This study aimed to develop the application of Photobacterium phosphoreum in traditional and novel fields - toxicity monitoring and biotechnology. We demonstrated (1) effects of selenite ions on bioluminescence, and (2) biotransformation of selenite to selenium(0) in the form of nanoparticles. The effects of selenite (SeO 3 ) on the intensity of bacterial bioluminescence were studied, and its dependencies on exposure time and concentration of Na 2- ) on the intensity of bacterial bioluminescence were studied, and its dependencies on exposure time and concentration of Na 2 were analyzed. Bioluminescence activation and inhibition were revealed; dose-effect dependencies corresponded to the hormesis model. The toxicity of SeO 3 was characterized by an effective concentration of 10 3 M. Effects of SeO 2- on reactive oxygen species (ROS) in bacterial suspensions were studied. High positive correlations were found between the bioluminescence intensity and ROS content, which indicates the decisive role of ROS and associated redox processes in the bioeffects of selenite ions. Scanning and transmission electron microscopy revealed the presence of nano-structures in the bacteria exposed to selenite. The energy dispersion spectrum detected a high content of selenium in the nanoparticles. The particle size distribution depended on Na -3 M. Effects of SeO 3 concentration; maxima of the distribution varied within 45-55 nm.2- on reactive oxygen species (ROS) in bacterial suspensions were studied. High positive correlations were found between the bioluminescence intensity and ROS content, which indicates the decisive role of ROS and associated redox processes in the bioeffects of selenite ions. Scanning and transmission electron microscopy revealed the presence of nano-structures in the bacteria exposed to selenite. The energy dispersion spectrum detected a high content of selenium in the nanoparticles. The particle size distribution depended on Na 2 SeO 3 concentration; maxima of the distribution varied within 45-55 nm., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Nadezhda S. Kudryasheva reports financial support was provided by Russian Science Foundation and Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Microbial reduction of selenium oxyanions, highly soluble, mobile and toxic inorganic selenium compounds, to insoluble selenium nanoparticles (Se NPs) is a widely spread phenomenon which is of geochemical, environmental and biotechnological importance. While selenite bioreduction is known for a wide variety of microorganisms, selenate bioreduction is not so common and has mostly been documented for anaerobes, with merely a few reported cases related to aerobic or microaerobic conditions. In some biogenic Se NPs of microbial origin, the presence of sulfur was detected together with selenium in Se NPs, particularly when increased concentrations of sulfate were present in the medium. In this work, the bacterial strain Azospirillum thiophilum BV-S, isolated earlier from a sulfur-containing aqueous environment (Lavrinenko et al. (2010), https://doi.org/10.1099/ijs.0.018853-0), has been shown to reduce selenite to Se NPs also in the presence of 7 mM sulfate in aerobic conditions. Raman spectroscopy was used to monitor the crystallinity and composition of Se NPs formed within the bacterial biomass in the presence of selenite and in the resulting isolated Se NPs, and their spherical morphology was visualised using transmission electron microscopy (TEM). While Se NPs both within the biomass and after isolation gave a typical strong broadened band at 248 cm -1 related to the stretching Se-Se vibrations in amorphous Se 0 , Raman spectrum of the biomass grown with 1 mM selenite + 7 mM sulfate showed also a weaker band at 348 cm -1 typical of the stretching Se-S mode. The absence of the latter band in Raman spectra of the isolated Se NPs indicates that the Raman-detected Se-S bonds most probably occur in intermediate substances such as selenodiglutathione (GS-Se-SG), an intermediary product in the Painter-type reaction of selenite reduction, which is known to undergo further enzymatic transformations in bacteria resulting in the formation of Se 0 . Strain A. thiophilum BV-S has also been found, for the first time for bacteria of the genus Azospirillum, to be capable of reducing selenate (Se VI O 4 ) under static conditions (similar to microaerobic conditions common to habitats of many Azospirillum species in different environments), but not in aerobic conditions, with the formation of Se NPs. The latter, giving a reddish coloration to the bacterial biomass, were characterised by TEM as round-shaped electron-dense structures over bacterial cell images. Raman spectra of the bacterial biomass after cultivation with 5 mM selenate (with or without added sulfate) showed a similar single band at ca. 248 cm 2- in amorphous Se NPs, although 5 mM sulfate slowed down their formation. However, no signs of sulfur covalently bound to Se were observed in Raman spectra in this case. These results indicate a possible negligible role of the selenodisulfide-involving pathway in selenate reduction by A. thiophilum with a noticeable possible interference of sulfate in the process of selenate uptake (i.e., a common transport route) by A. thiophilum cells.-1 in amorphous Se NPs, although 5 mM sulfate slowed down their formation. However, no signs of sulfur covalently bound to Se were observed in Raman spectra in this case. These results indicate a possible negligible role of the selenodisulfide-involving pathway in selenate reduction by A. thiophilum with a noticeable possible interference of sulfate in the process of selenate uptake (i.e., a common transport route) by A. thiophilum cells., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Anna V. Tugarova reports financial support was provided by the Russian Science Foundation. Co-author (A.A. Kamnev) is Guest Editor of the VSI: CSI XLIII 2023 to which we submit our manuscript. The other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this study, we analyze a series of molecules belonging to the C 2V (M) molecular symmetry group which are characterized by several conformers. The use of molecular symmetry at each stage of calculating the energy of stationary torsional states is demonstrated. In particular, the importance is shown of preliminary symmetrization of physical characteristics of the molecules obtained by quantum chemical calculations. For the first time, symmetry-adapted basis functions for the diagonal kinetic coefficients are presented, which for the analyzed molecules do not satisfy all symmetry operations of the C 2V (M) group. Using the HSSSH molecule as an example, it is shown how the full or partial accounting for molecular symmetry influences the calculated values of ultra-small tunneling splittings of the ground torsional states of the trans- and cis-conformers. It has also been established that the Hamiltonian matrix is characterized by symmetry which, when taken into account, makes it possible to halve the time of calculation of its elements., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The possibility of the reaction of ethylene at cryogenic temperatures with dinitrogen tetroxide (N 2 O 4 ), at least at -40 °C, has been demonstrated. An infrared (IR) spectroscopic analysis of the condensed reaction products was carried out, which showed the presence of substances containing organic nitro compounds and organic nitrates. The latter particularly means the possibility of the formation of explosive substances, as in the known explosive cryogenic reaction of N 2 O 4 with butadiene. The fundamental possibility of such a reaction is of importance for the organization of cryogenic production of gases from raw materials containing ethylene and nitrogen oxide impurities. The sensitivity of the experimental setup was demonstrated by using the example of the known reaction of N 2 O 4 with butadiene. The temperature and time characteristics of the latter reaction have been found. To determine the temperature range of possible reactions of ethylene with N 2 O 4 , thermograms of the process of heating the reactive mixture at a constant rate were analyzed. To ensure the sensitivity of the qualitative analysis of thermograms of the reaction of ethylene with N 2 O 4 in the linear heating mode, a quasi-differential method was proposed that uses the temperature of the cryo-thermostat coolant, which varies linearly with time, as the reference temperature. Some recently published theoretical results concerning the mechanisms of N 2 O 4 isomerization are discussed which may be useful for further studies in establishing the mechanisms and predicting the ratios of the products and their yields for the reaction of N 2 O 4 with olefins under particular experimental conditions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Splitting of the ground state and some excited symmetric bending vibrational states due to inversion tunneling of the oxygen atom in the H 3 O + , H 3 O - ions and in the H 3 O radical are analyzed by numerically solving the vibrational Schrödinger equation of restricted (2D) dimensionality. As two vibrational coordinates, we used 1) the distance of the oxygen atom from the plane of a regular triangle formed by three hydrogen atoms and 2) a symmetry coordinate composed of three distances between chemically non-bonded hydrogen atoms. The kinetic energy operator in this case takes the simplest form. The 2D potential energy surface (PES) in the given coordinates was calculated for H 3 O + at the CCSD(T)/aug-cc-pVTZ and CCSD(T)-F12/cc-pVTZ-F12 levels of theory. The same 2D PES for the H 3 O - anion and H 3 O radical were calculated at the CCSD(T)/aug-cc-pVQZ, CCSD(T)/d-aug-cc-pVQZ and UCCSD(T)/aug-cc-pVQZ, UCCSD(T)/d-aug-cc-pVQZ levels of theory, respectively. The tunneling splittings were calculated for the cations H 3 16 O + , D 3 16 O + , T 3 16 O + , H 3 18 O + , D 3 18 O + , T 3 18 O + anions and H 3 O - , D 3 O radicals were calculated for the first time. The results of calculations demonstrate good agreement with experimental values of the tunneling splittings in the ground state and in some excited vibrational states of the H - , T 3 and D - anions and H 3 O, D 3 O, T 3 O radicals were calculated for the first time. The results of calculations demonstrate good agreement with experimental values of the tunneling splittings in the ground state and in some excited vibrational states of the H 3 16 O + and D 3 16 O + cations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Monitoring of poly-3-hydroxybutyrate accumulation and changes in its relative contents in biomass of the plant-growth-promoting bacteria Azospirillum brasilense (strains Sp7, Cd and Sp245) was performed during aerobic cultivation for 1 to 8 days at various initial concentrations of bound nitrogen (0.1 to 0.5 g∙L -1 NH 4 Cl) in the culture medium using in-situ transmission FTIR spectroscopy. A methodology has been proposed based on calculating band areas in FTIR spectra (instead of band intensities commonly used earlier) for determining relative contents of PHB in dry bacterial biomass, using the ester ν(C=O) band as a PHB marker (in the region 1750-1720 cm -1 ) and amide II band of cellular proteins (at ca. 1540 cm -1 ). Differences in PHB accumulation levels and their changes in the course of cultivation under various trophic stress for the three strains are discussed in relation to their different ecological niches which they occupy in the rhizosphere., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The hydrogen trioxide (HT) molecule HOOOH is 1) a prototype for a class of molecules of the form X(ZY) 2 with two equivalent internal tops (ZY) and 2) the second representative of the polyoxides series of the form HO n H (n ≥ 2). Due to this, it is the subject of close attention of researchers. In this paper, we performed a group theory analysis of the torsional and spin states of the HOOOH, DOOOH, and DOOOD molecules. The relationships have been established between the symmetry species of the C 2V (M) molecular symmetry group to which the HOOOH and DOOOD molecules belong, and the symmetry species of the C 2 and C S point groups to which the equilibrium configurations of trans- and cis-conformers of the above molecules belong, respectively. 2D PES and 2D surfaces of kinematic coefficients related to torsional vibrations of hydroxyl groups were calculated at the complete basis set (CBS) limit by extrapolating the results of calculations at the MP2/cc-pVTZ and MP2/cc-pVQZ levels of theory. For all the three molecules, the energies of the stationary torsional states were computed using the Fourier method for a numerical solution of the 2D vibrational Schrödinger equation. Symmetry species of torsional states and the values of quantum numbers defining the types of torsional vibrations were found by analyzing the torsional wave functions. The selection rules for transitions between torsional states in the dipole approximation were also formulated., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Microbial cells are well known to be capable of remaining viable when desiccated, and a variety of beneficial microorganisms can thus be preserved for storage. For the ubiquitous widely studied soil bacterium Azospirillum brasilense (wild-type strain Sp7), which has a significant agrobiotechnological potential owing to its plant-growth-promoting capabilities perspective for its use in biofertilisers, Fourier transform infrared (FTIR) spectroscopy (in the diffuse reflectance mode, DRIFT) was used to control the state of biomass, together with 57 Fe transmission Mössbauer spectroscopy to monitor intracellular iron speciation in live rapidly frozen cell suspension and in the lyophilised biomass (both measured at T = 80 K). It has been shown for the first time that a relatively large part of ferrous iron in live cells (22% of the whole cellular iron pool, represented by two high-spin Fe(II) forms, in the 18-h culture grown on 57 Fe(III) complex with nitrilotriacetic acid as the sole source of iron) gets largely oxidised upon lyophilisation. The remaining part of iron(II) in the resulting dry biomass was found to be ca. 3% only. The major part of ferric iron in the dry biomass was shown to be comprised of ferritin-like ferric species (giving a typical magnetically split sextet at T = 5 K), while the iron(III) formed from cellular iron(II) by oxidation in air in the course of drying remained in a paramagnetic state even at T = 5 K. The possibility of intracellular iron(II) oxidation to iron(III) upon desiccation may be a specific natural strategy to avoid cell damage caused by Fenton-type reactions in dormant (frozen, dried) cells. The results obtained may have important implications related to iron speciation and redox transformations in dried bacterial preparations intended for long-term storage., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Raman spectra of liquid water and ice were measured at different temperatures. The intensity of the band assigned to bending vibrations of water molecules was observed to decrease at the liquid-to-solid transition, while the Raman line near 2200cm -1 showed an anomalously high intensity in the solid phase. A tetrahedral model was used for computer analysis of the observed spectral changes. Quantum-chemical calculations of the structure, normal vibrations and Raman spectra in the harmonic approximation, as well as frequencies and intensities of some vibrations using 1D and 2D potential energy surfaces, were carried out using B3LYP with the cc-pVTZ basis set. The influence of the number of hydrogen bonds on the frequency and Raman activity of the bending vibrations was analyzed. The possibility of hydrogen bond weakening upon excitation of the combined bending-rocking vibration due to the large amplitude of this vibration is considered., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Vibrational (Fourier transform infrared (FTIR) and Raman) spectroscopic techniques can provide unique molecular-level information on the structural and compositional characteristics of complicated biological objects. Thus, their applications in microbiology and related fields are steadily increasing. In this communication, biogenic selenium nanoparticles (Se NPs) were obtained via selenite (SeO 3 ) reduction by the bacterium Azospirillum thiophilum (strain VKM B-2513) for the first time, using an original methodology for obtaining extracellular NPs. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed the Se NPs to have average diameters within 160-250nm; their zeta potential was measured to be minus 18.5mV. Transmission FTIR spectra of the Se NPs separated from bacterial cells showed typical proteinacious, polysaccharide and lipid-related bands, in line with TEM data showing a thin layer covering the Se NPs surface. Raman spectra of dried Se NPs layer in the low-frequency region (under 500cm 2- ) reduction by the bacterium Azospirillum thiophilum (strain VKM B-2513) for the first time, using an original methodology for obtaining extracellular NPs. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) showed the Se NPs to have average diameters within 160-250nm; their zeta potential was measured to be minus 18.5mV. Transmission FTIR spectra of the Se NPs separated from bacterial cells showed typical proteinacious, polysaccharide and lipid-related bands, in line with TEM data showing a thin layer covering the Se NPs surface. Raman spectra of dried Se NPs layer in the low-frequency region (under 500cm -1 down to 150cm -1 ) showed a single very strong band with a maximum at 250cm -1 at half intensity), can be attributed to amorphous elementary Se. Thus, a combination of FTIR and Raman spectroscopic approaches is highly informative in non-destructive analysis of structural and compositional properties of biogenic Se NPs.-1 at half intensity), can be attributed to amorphous elementary Se. Thus, a combination of FTIR and Raman spectroscopic approaches is highly informative in non-destructive analysis of structural and compositional properties of biogenic Se NPs., (Copyright © 2017 Elsevier B.V. All rights reserved.)

In the emission ( 57 Co) variant of Mössbauer spectroscopy (EMS), the 57 Co radionuclide (with a half-life of 9months) is used that undergoes a nuclear decay 57 Co→ 57 Fe via electron capture followed by the emission of a γ-quantum, the energy of which is modified by the chemical state and the close coordination environment of the parent 57 Co atom. While EMS has been used largely in materials science and nuclear chemistry, its high sensitivity can also be of great advantage in revealing fine structural features and for speciation analysis of biological complexes, whenever the 57 Co 2+ cation can be used directly as the coordinating metal or as a substitute for native cobalt or other metal ions. As such EMS applications are yet rare, in order to reliably interpret emission spectra of sophisticated 57 Co 2+ -doped biosystems, model EMS studies of simple cobalt biocomplexes are necessary. In this work, EMS spectroscopic data are analysed and discussed for 57 Co 2+ complexes with a range of small biomolecules of different structures, including 4-n-hexylresorcinol, homoserine lactone and a few amino acids (spectra measured in rapidly frozen dilute aqueous solutions or in the dried state at T=80K). The EMS data obtained are discussed with regard to the available literature data related to the coordination modes of the biocomplexes under study., (Copyright © 2016. Published by Elsevier B.V.)

The integral bioluminescence (BL) intensity of live Photobacterium phosphoreum cells (strain 1883 IBSO), sampled at the stationary growth stage (20 h), was monitored for further 300 h in the absence (control) and presence of (241)Am (an α-emitting radionuclide of a high specific activity) in the growth medium. The activity concentration of (241)Am was 2 kBq l(-1); [(241)Am]=6.5×10(-11) M. Parallel experiments were also performed with water-soluble humic substances (HS, 2.5 mg l(-1); containing over 70% potassium humate) added to the culture medium as a possible detoxifying agent. The BL spectra of all the bacterial samples were very similar (λ(max)=481±3 nm; FWHM=83±3 nm) showing that (241)Am (also with HS) influenced the bacterial BL system at stages prior to the formation of electronically excited states. The HS added per se virtually did not influence the integral BL intensity. In the presence of (241)Am, BL was initially activated but inhibited after 180 h, while the system (241)Am+HS showed an effective activation of BL up to 300 h which slowly decreased with time. Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, applied to dry cell biomass sampled at the stationary growth phase, was used to control possible metabolic responses of the bacteria to the α-radioactivity stress (observed earlier for other bacteria under other stresses). The DRIFT spectra were all very similar showing a low content of intracellular poly-3-hydroxybutyrate (at the level of a few percent of dry biomass) and no or negligible spectroscopic changes in the presence of (241)Am and/or HS. This assumes the α-radioactivity effect to be transmitted by live cells mainly to the bacterial BL enzyme system, with negligible structural or compositional changes in cellular macrocomponents at the stationary growth phase., (Copyright © 2012 Elsevier B.V. All rights reserved.)