Raman spectroscopic and TEM monitoring of selenite and selenate reduction by the bacterium Azospirillum thiophilum with the formation of selenium(0) nanoparticles: Effects of sulfate.

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.

How symmetry helps to improve the estimation of the hyperfine splitting of torsional levels due to tunneling. The case of the HSSSH molecule.

In this study, we analyze a series of molecules belonging to the C(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.

Role of Denitrification in Selenite Reduction by with the Formation of Selenium Nanoparticles.

Background: Many bacteria are capable of reducing selenium oxyanions, primarily selenite (SeO), in most cases forming selenium(0) nanostructures. The mechanisms of these transformations may vary for different bacterial species and have so far not yet been clarified in detail. Bacteria of the genus , including ubiquitous phytostimulating rhizobacteria, are widely studied and have potential for agricultural biotechnology and bioremediation of excessively seleniferous soils, as they are able to reduce selenite ions.

Application of the luminous bacterium Photobacterium phosphoreum for toxicity monitoring of selenite and its reduction to selenium(0) nanoparticles.

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.

Infrared spectroscopic and thermographic evidence for the interaction of ethylene and 1,3-butadiene with NO at cryogenic temperatures.

The possibility of the reaction of ethylene at cryogenic temperatures with dinitrogen tetroxide (NO), 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 NO with butadiene.

A convenient set of vibrational coordinates for 2D calculation of the tunneling splittings of the ground state and some excited vibrational states for the inversion motion in HO, HO, and HO.

Splitting of the ground state and some excited symmetric bending vibrational states due to inversion tunneling of the oxygen atom in the HO, HO ions and in the HO 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.

Fourier Transform Infrared (FTIR) Spectroscopic Study of Biofilms Formed by the Rhizobacterium Sp245: Aspects of Methodology and Matrix Composition.

Biofilms represent the main mode of existence of bacteria and play very significant roles in many industrial, medical and agricultural fields. Analysis of biofilms is a challenging task owing to their sophisticated composition, heterogeneity and variability. In this study, biofilms formed by the rhizobacterium (strain Sp245), isolated biofilm matrix and its macrocomponents have for the first time been studied in detail, using Fourier transform infrared (FTIR) spectroscopy, with a special emphasis on the methodology.

Isolation and Characterization of 1-Hydroxy-2,6,6-trimethyl-4-oxo-2-cyclohexene-1-acetic Acid, a Metabolite in Bacterial Transformation of Abscisic Acid.

We report the discovery of a new abscisic acid (ABA) metabolite, found in the course of a mass spectrometric study of ABA metabolism by the rhizosphere bacterium sp. P1Y. Analogue of (+)-ABA, enriched in tritium in the cyclohexene moiety, was fed in bacterial cells, and extracts containing radioactive metabolites were purified and analyzed to determine their structure.

Selenite Reduction by sp. YS02: New Insights Revealed by Comparative Transcriptomics and Antibacterial Effectiveness of the Biogenic Se Nanoparticles.

Biotransformation of selenite by microorganisms is an effective detoxification (in cases of dissimilatory reduction, e.g., to Se) and assimilation process (when Se is assimilated by cells).

Fourier Transform Infrared (FTIR) Spectroscopic Analyses of Microbiological Samples and Biogenic Selenium Nanoparticles of Microbial Origin: Sample Preparation Effects.

To demonstrate the importance of sample preparation used in Fourier transform infrared (FTIR) spectroscopy of microbiological materials, bacterial biomass samples with and without grinding and after different drying periods (1.5-23 h at 45 °C), as well as biogenic selenium nanoparticles (SeNPs; without washing and after one to three washing steps) were comparatively studied by transmission FTIR spectroscopy. For preparing bacterial biomass samples, Sp7 and Sp245 (earlier known as Sp245) were used.

Poly-3-hydroxybutyrate synthesis by different Azospirillum brasilense strains under varying nitrogen deficiency: A comparative in-situ FTIR spectroscopic analysis.

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 NHCl) in the culture medium using in-situ transmission FTIR spectroscopy.

Developments in the study and applications of bacterial transformations of selenium species.

Microbial bio-transformations of the essential trace element selenium are now recognized to occur among a wide variety of microorganisms. These transformations are used to convert this element into its assimilated form of selenocysteine, which is at the active center of a number of key enzymes, and to produce selenium nanoparticles, quantum dots, metal selenides, and methylated selenium species that are indispensable for biotechnological and bioremediation applications. The focus of this review is to present the state-of-the-art of all aspects of the investigations into the bacterial transformations of selenium species, and to consider the characterization and biotechnological uses of these transformations and their products.

Selenite reduction by the rhizobacterium Azospirillum brasilense, synthesis of extracellular selenium nanoparticles and their characterisation.

Microbial reduction of selenium oxyanions has attracted attention in recent years. In this study, an original and simple method for the synthesis of extracellular selenium nanoparticles (Se NPs) of relatively uniform size has been developed using strains Sp7 and Sp245 of the ubiquitous plant-growth promoting rhizobacterium Azospirillum brasilense, both capable of selenite (SeO) reduction. In addition, a reliable purification protocol for the recovery of the Se NPs has been perfected, which could be applied with minor modifications to cultures of other microbial species.

Diffuse reflectance infrared Fourier transform (DRIFT) and Mössbauer spectroscopic study of Azospirillum brasilense Sp7: Evidence for intracellular iron(II) oxidation in bacterial biomass upon lyophilisation.

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 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 Fe(III) complex with nitrilotriacetic acid as the sole source of iron) gets largely oxidised upon lyophilisation.

FTIR and Raman spectroscopic studies of selenium nanoparticles synthesised by the bacterium Azospirillum thiophilum.

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) reduction by the bacterium Azospirillum thiophilum (strain VKM B-2513) for the first time, using an original methodology for obtaining extracellular NPs.

Sample treatment in Mössbauer spectroscopy for protein-related analyses: Nondestructive possibilities to look inside metal-containing biosystems.

In this review, the unique possibilities are considered of the Fe transmission (TMS) and Co emission (EMS) variants of Mössbauer (nuclear γ-resonance) spectroscopy as nondestructive techniques with minimal sample preparation/treatment and a significant analytical potential, with a focus on the analysis of cation-binding sites in metalloproteins. The techniques are shown to provide unique structural and quantitative information on the coordination microenvironment, the chemical state and transformations of the Mössbauer nuclides in sophisticated metal-containing proteins, including those within complicated supramolecular structures, and in microbial cells or tissues. Recent representative examples of analyses of Fe-containing proteins by Fe TMS are briefly discussed, along with the newly emerging data on using Co EMS for probing the structural organisation of Co-doped cation-binding sites in sophisticated biocomplexes including metalloenzymes.

Proteins in microbial synthesis of selenium nanoparticles.

Biogenic formation of nano-sized particles composed of various materials (in particular, selenium) by live microorganisms is widespread in nature. This phenomenon has been increasingly attracting the attention of researchers over the last decade not only owing to a range of diverse applications of such nanoparticles (NPs) in nanobiotechnology, but also because of the specificity of methodologies and mechanisms of NPs formation related to "green synthesis". In this mini-review, recent data are discussed on the multifaceted role of proteins in the processes of microbial reduction of selenium oxyanions and the formation of Se NPs.

Cobalt(II) complexation with small biomolecules as studied by Co emission Mössbauer spectroscopy.

In the emission (Co) variant of Mössbauer spectroscopy (EMS), the Co radionuclide (with a half-life of 9months) is used that undergoes a nuclear decay Co→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 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 Co 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 Co-doped biosystems, model EMS studies of simple cobalt biocomplexes are necessary.

Evidence for ferritin as dominant iron-bearing species in the rhizobacterium Azospirillum brasilense Sp7 provided by low-temperature/in-field Mössbauer spectroscopy.

For the ubiquitous diazotrophic rhizobacterium Azospirillum brasilense, which has been attracting the attention of researchers worldwide for the last 35 years owing to its significant agrobiotechnological and phytostimulating potential, the data on iron acquisition and its chemical speciation in cells are scarce. In this work, for the first time for azospirilla, low-temperature (at 80 K, 5 K, as well as at 2 K without and with an external magnetic field of 5 T) transmission Mössbauer spectroscopic studies were performed for lyophilised biomass of A. brasilense (wild-type strain Sp7 grown with (57)Fe(III) nitrilotriacetate complex as the sole source of iron) to enable quantitative chemical speciation analysis of the intracellular iron.

Reduction of selenite by Azospirillum brasilense with the formation of selenium nanoparticles.

The ability to reduce selenite (SeO(3)(2-)) ions with the formation of selenium nanoparticles was demonstrated in Azospirillum brasilense for the first time. The influence of selenite ions on the growth of A. brasilense Sp7 and Sp245, two widely studied wild-type strains, was investigated.

Gold(III) reduction by the rhizobacterium Azospirillum brasilense with the formation of gold nanoparticles.

For the soil nitrogen-fixing bacterium Azospirillum brasilense, the ability to reduce [AuCl4](-) and to form gold nanoparticles (GNPs) has been demonstrated, with the appearance of a mauve tint of the culture. To validate the shapes and chemical nature of nanoparticles, transmission electron microscopy (TEM) and X-ray fluorescence analysis were used. For the widely studied agriculturally important wild-type strains A.

Scientific Globish versus scientific English.

The proposed adoption of 'scientific Globish' as a simplified language standard for scholarly communication may appeal to authors who have difficulty with English proficiency. However, Globish might not justify the hopes being pinned on it and might open the door to further deterioration of the quality of English-language scientific writing.