X-ray Fluorescence Techniques in Determining the Habitat Preferences of Species-Ulva pilifera (Ulvales, Chlorophyta) from Montenegro Case Study.

The paper presents four new sites where bright green Ulva thalli were found inhabiting freshwater (a river, a ditch, the Milet Canal) and marine (on the rocky shore of the Adriatic Sea) habitats in Montenegro. The aims of this study were to determine, for the first time, whether specimens of Ulva pilifera collected in Montenegro are phylogenetically and morphologically the same species as the one occurring in Europe. Using total reflection X-ray fluorescence (TXRF) and wavelength dispersive X-ray fluorescence (WDXRF) techniques it assessed the elemental composition of their thalli and its influence to colonise new habitats. Elements: Al, As, Ba, Br, Ca, Cl, Cr, Cu, Fe, Hf, I, K, Mg, Mn, Na, Ni, P, Pb, Rb, S, Si, Sr, Ti, V, and Zn were determined. The highest elemental concentrations were found for Ca = 16.3% (using WDXRF) and for Sr = 292 ppm (using TXRF) in the Ulva thalli. Ulva pilifera analysed from Montenegro, based on classical morphological methods and molecular techniques, are closely related to the same species from inland and coastal waters throughout Europe. The analysis of trace elements showed that the metal content in Ulva thalli is correlated with the trace elements in water and sediments. Ulva pilifera fits numerous features that make it one of the bioindicators of marine pollution, thanks to its worldwide distribution and capacity to accumulate trace elements.

The role of sirtuns in cellular homeostasis

Sirtuins are evolutionarily conserved nicotinamide adenine dinucleotide (NAD+)-dependent lysine deacylases or ADP-ribosyltransferases. These cellular enzymes are metabolic sensors sensitive to NAD+ levels that maintain physiological homeostasis in the animal and plant cells (AU)

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The Determination of Protonation Constants of Peptidomimetic Cyclophanes in Binary Methanol-Water Mixtures.

The protonation constants of new group of peptidomimetic cyclophanes with valine or phenylalanine moieties incorporated into the macrocyclic skeleton as well as their linear analogues were determined by potentiometric measurements in solutions of methanol-water mixtures at 25°C and constant ionic strength. The influence of cavity size, location of protonation sites, and attached substituents of the macrocyclic ligands on the protonation constants were discussed on the basis of potentiometric measurement as well as H(1)-NMR results.

The role of sirtuins in cellular homeostasis.

Sirtuins are evolutionarily conserved nicotinamide adenine dinucleotide (NAD(+))-dependent lysine deacylases or ADP-ribosyltransferases. These cellular enzymes are metabolic sensors sensitive to NAD(+) levels that maintain physiological homeostasis in the animal and plant cells.

Silver complexes of peptidomimetic polyazapyridinophanes. The influence of the bonding cavity size and the nature of side chains.

Several peptidomimetic macrocycles containing a pyridine spacer and ring sizes ranging from 15 to 17 have been efficiently synthesized starting from valine and phenylalanine. The complexes formed have been investigated by potentiometry and NMR. Log K values show that phenylalanine derivatives are consistently more stable than valine derivatives , whilst macrocycles with ring sizes of 16 members are the most appropriate for the complexation. The NMR data, in combination with molecular modeling, allow rationalization of the structure of the complexes formed and the participation of the aromatic rings from the side chain of phenylalanine in pi-Ag+ interactions to be discarded.