Spatio-Temporal Variation of the Bacterial Communities along a Salinity Gradient within a Thalassohaline Environment (Saline di Tarquinia Salterns,Italy)

The “Saline di Tarquinia” salterns have been scarcely investigated regarding their microbiological aspects. This work studied the structure and composition of their bacterial communities along the salinity gradient (from the nearby sea through different ponds). The communities showed increasing simplification of pond bacterial diversity along the gradient (particularly if compared to those of the sea). Among the 38 assigned phyla, the most represented were Proteobacteria, Actinobacteria and Bacteroidetes. Differently to other marine salterns, where at the highest salinities Bacteroidetes dominated, preponderance of Proteobacteria was observed. At the genus level the most abundant taxa were Pontimonas, Marivita, Spiribacter, Bordetella, GpVII and Lentibacter. The α-diversity analysis showed that the communities were highly uneven, and the Canonical Correspondence Analysis indicated that they were structured by various factors (sampling site, sampling year, salinity, and sampling month). Moreover, the taxa abundance variation in relation to these significant parameters were investigated by Generalized Linear Models. This work represents the first investigation of a marine saltern, carried out by a metabarcoding approach, which permitted a broad vision of the bacterial diversity, covering both a wide temporal span (two years with monthly sampling) and the entire salinity gradient (from the nearby sea up to the crystallisation ponds).     

Parameters influencing the capacitive behavior of carbon composite electrodes: composition,morphology, electrical conductivity,and surface chemistry

Journal of Solid State Electrochemistry - The interplay and overlapping of several factors determine the capacitive behavior of carbon composite electrodes for capacitive energy storage...     

Formation of Chiral Structures in Photoinitiated Formose Reaction

The possibility to synthesize biologically important sugars and other chiral compounds without any initiators in the UV-initiated reaction of formaldehyde in aqueous solution has been shown for the first time. An optically active condensed phase due to an sp³-hybridized carbon atom has been detected. It has been shown that this phase is formed due to the spatial cleavage of antipodes in the racemate, similar to the cleavage of enantiomers following the sign of chirality in the known experiments of Pasteur. The results have been obtained under the conditions that correspond to modern ideas about the form and vector of prebiological evolution and, therefore, can be of fundamental importance for understanding the processes of biopoiesis.     

A Study on the phase transition in decamethylosmocene crystal over a wide temperature range

The reversible structural phase transition accompanied by the doubling of the unit cell parameter c and a change in the space group is found in the decamethylosmocene crystal Cp ₂ ^* at a temperature of 243 ± 5 K. In the high-temperature (HT) phase (space group P2₁/m, Z = 2), the molecule adopts an eclipsed conformation and lies in the mirror symmetry plane. In the low-temperature (LT) phase (space group P2₁/c, Z = 4), the molecule occupies the general position with a small rotation of the ligands. The structural transformations from the high-temperature phase into the low-temperature phase at 120 K are described by the deviation of the molecular axis of fivefold symmetry by 3.2(2)° and the displacement of the center of mass of the molecule by 0.173(2) Å with respect to their positions in the high-temperature phase, and also by the rotation of the Cp* ligands in the same direction by 3.0(2)° and 5.4(2)°, respectively.     

Analysis of chemical bonding in the α and β modifications of zinc diphosphide from X-ray diffraction data

With the aim of studying the characteristic features of chemical interactions between atoms in the α (red tetragonal) and β (black monoclinic) modifications of zinc diphosphide, the maps of deformation electron-density distribution at the P-P and P-Zn bonds were constructed from precision X-ray diffraction data. The P-P bonds were demonstrated to be of a pronounced covalent nature. The maxima in the Zn-P bonds are shifted to the electronegative phosphorus atom, which is indicative of a mixed ionic-covalent nature of the bond, with the ionicity being higher in the α than in the β modification. Based on the dependence of the contribution of the metallic component on the delocalized electron density, it was concluded that the contribution of the metallic component is more pronounced in the black than in the red modification. An increase in the bond ionicity and the absence of delocalized electrons result in an increase in the forbidden gap in the red modification compared to its increase in the black modification.     

Molecular and crystal structures of decamethylruthenocene (η5-C5Me5)2Ru in the temperature range 153–300 K: Thermal motion in a crystal according to X-ray diffraction data

The crystal structure of decamethylruthenocene (η⁵-C₅ Me ₅)₂Ru (I) is investigated by X-ray diffraction. It is demonstrated that the compound studied crystallizes in two polymorphic modifications, namely, modification Ia with space group P2₁/m (Z = 2) in the temperature range 153–300 K and modification Ibwith space group P2₁/n (Z = 4) at 203 K. No temperature phase transition between the modifications is found. In crystal Ia, the molecule occupies a special position in the mirror plane. In crystal Ib, the molecule is located in the general position. The cyclic ligands η⁵-C₅ Me ₅, (Cp*) are aligned parallel to each other and adopt an eclipsed conformation. The bond lengths in compounds Ia and Ib are identical. Analysis of the anisotropic displacement parameters of the atoms indicates that molecules Ia and Ib are not structurally rigid and that the Cp* rings involved in these molecules can execute independent librations. In the temperature range 153–300 K, the Cp*(1) ligand in molecule Ia is statically disordered over two positions. The barrier heights B ₅ for rotation of the Cp* ligands are estimated both from the root-mean-square amplitudes of librations 〈ϕ²〉 and with the use of the atom-atom potential method. __________ Translated from Kristallografiya, Vol. 48, No. 2, 2003, pp. 283–292. Original Russian Text Copyright ? 2003 by Zanin, Antipin.     

Ordered mesoporous Co3O4 as highly active catalyst for low temperature CO-oxidation

Cubic ordered mesoporous Co(3)O(4), prepared via the nanocasting pathway using KIT-6 as hard template, was found to be an excellent catalyst for low temperature CO oxidation, with the activity clearly depending on surface area and pore systems of the catalysts.     

Can a synthetic thread act as an electrochemically switchable molecular device?

Here we report that at room temperature in acetonitrile after the reduction of the naphthalimide-site, a synthetic molecular thread undergoes a complete conformational change which makes possible an efficient conversion of chemical energy into mechanical work; such results point out the ability of the thread to act as a molecular device under electrochemical control.     

Sequential Production of Amylolytic and Lipolytic Enzymes by Bacterium Strain Isolated from Petroleum Contaminated Soil

Amylases and lipases are highly demanded industrial enzymes in various sectors such as food, pharmaceuticals, textiles, and detergents. Amylases are of ubiquitous occurrence and hold the maximum market share of enzyme sales. Lipases are the most versatile biocatalyst and bring about a range of bioconversion reactions such as hydrolysis, inter-esterification, esterification, alcoholysis, acidolysis, and aminolysis. The objective of this work was to study the feasibility for amylolitic and lipolytic production using a bacterium strain isolated from petroleum contaminated soil in the same submerged fermentation. This was a sequential process based on starch and vegetable oils feedstocks. Run were performed in batchwise using 2% starch supplemented with suitable nutrients and different vegetable oils as a lipase inducers. Fermentation conditions were pH 5.0; 30 degrees C, and stirred speed (200 rpm). Maxima activities for amyloglucosidase and lipase were, respectively, 0.18 and 1,150 U/ml. These results showed a promising methodology to obtain both enzymes using industrial waste resources containing vegetable oils.