Biotechnology Research Abstracts

Ribose methylation is among the most ubiquitous modifications found in RNA. 2'-O-methyluridine is found in rRNA, snRNA, snoRNA and tRNA of Archaea, Bacteria, and Eukaryota. Moreover, 2'-O-methylribonucleosides are promising starting materials for the production of nucleic acid-based drugs. Despite the countless possibilities of practical use for the metabolic enzymes associated with methylated nucleosides, there are very few reports regarding the metabolic fate and enzymes involved in the metabolism of 2'-O-alkyl nucleosides. The presented work focuses on the cellular degradation of 2'-O-methyluridine. A novel enzyme was found using a screening strategy that employs Escherichia coli uracil auxotroph and the metagenomic libraries. A 2'-O-methyluridine hydrolase (RK9NH) has been identified together with an aldolase (RK9DPA)-forming a part of a probable gene cluster that is involved in the degradation of 2'-O-methylated nucleosides. The RK9NH is functional in E. coli uracil auxotroph and in vitro. The RK9NH nucleoside hydrolase could be engineered to enzymatically produce 2'-O-methylated nucleosides that are of great demand as raw materials for production of nucleic acid-based drugs. Moreover, RK9NH nucleoside hydrolase converts 5-fluorouridine, 5-fluoro-2'-deoxyuridine and 5-fluoro-2'-O-methyluridine into 5-fluorouracil, which suggests it could be employed in cancer therapy.

Sm3+-Doped and Eu3+/Sm3+-co-doped yttrium aluminium garnets (YAG) have been synthesized by an environmentally friendly sol–gel method. The results of X-ray diffraction (XRD) analysis of the powders sintered at 1000 1C showed the high purity of the end products with formation of monophasic compounds. The phase composition of the samples was also investigated by FTIR spectroscopy. The microstructural features of the polycrystalline samples were studied by scanning electron microscopy (SEM). The local environments of Eu3+ and Sm3+ activator ions in the garnet crystal structure compounds were investigated by nuclear magnetic resonance (NMR) and Raman spectroscopy. The luminescence properties were discussed using the results from photoluminescence (PL) study. The effective concentration of Sm in YAG was estimated and optimum ratio between two activators (Eu3+ and Sm3+) was analysed. The correlation between structural features and luminescence was determined. With a constant amount of samarium in Y2.9Sm0.1Al5O12:Eu garnet the strongest luminescence was determined in the sample with 1% of europium when characteristic excitation for europium was used.