SEPARATION OF CESIUM AND ALUMINUM BY CATION-EXCHANGER PUROLITE C-160

The possibility of cesium separation from aluminum during conversion of waste of catalysts processing by use of сation-exchanger Purolite C-160 at different pH was studied. The separation of these elements was not possible in the pH range of (2,0 – 10,0)

PROCESSING OF SULFURIC-ACID SOLUTIONS OF URANIUM IN SITU LEACHING WITH HIGH CONTENT OF CHLORINE

The processing of sulfuric-acid solutions after uranium in situ leaching with high content of chlorine was studied. The precipitation by different methods allows to obtain uranium con-centrates with high quality according to ASTM C967-13

RecG directs DNA synthesis during double-strand break repair

Homologous recombination provides a mechanism of DNA double-strand break repair (DSBR) that requires an intact, homologous template for DNA synthesis. When DNA synthesis associated with DSBR is convergent, the broken DNA strands are replaced and repair is accurate. However, if divergent DNA synthesis is established, over-replication of flanking DNA may occur with deleterious consequences. The RecG protein of Escherichia coli is a helicase and translocase that can re-model 3-way and 4-way DNA structures such as replication forks and Holliday junctions. However, the primary role of RecG in live cells has remained elusive. Here we show that, in the absence of RecG, attempted DSBR is accompanied by divergent DNA replication at the site of an induced chromosomal DNA double-strand break. Furthermore, DNA double-stand ends are generated in a recG mutant at sites known to block replication forks. These double-strand ends, also trigger DSBR and the divergent DNA replication characteristic of this mutant, which can explain over-replication of the terminus region of the chromosome. The loss of DNA associated with unwinding joint molecules previously observed in the absence of RuvAB and RecG, is suppressed by a helicase deficient PriA mutation (priA300), arguing that the action of RecG ensures that PriA is bound correctly on D-loops to direct DNA replication rather than to unwind joint molecules. This has led us to put forward a revised model of homologous recombination in which the re-modelling of branched intermediates by RecG plays a fundamental role in directing DNA synthesis and thus maintaining genomic stability

INTERNALIZATION OF ANTIMICROBIAL PEPTIDE ACIPENSIN 1 INTO HUMAN TUMOR CELLS

Search for new compounds providing delivery of drugs into infected or neoplastic cells, is an important direction of biomedical research. Cell-penetrating peptides are among those compounds, due to their ability to translocate through membranes of eukaryotic cells, serving as potential carriers of various therapeutic agents to the target cells. The aim of present work was to investigate the ability of acipensin 1, an antimicrobial peptide of innate immune system, for in vitro penetration into human tumor cells. Acipensin 1 is a cationic peptide that we have previously isolated from leukocytes of the Russian sturgeon, Acipenser gueldenstaedtii. Capability of acipensin 1 to enter the human erytroleukemia K-562 cells has been investigated for the first time. A biotechnological procedure for producing a recombinant acipensin 1 peptide has been developed. The obtained peptide was conjugated with a fluorescent probe BODIPY FL. By means of confocal microscopy, we have shown that the tagged acipensin 1 rapidly enters into K-562 cells and can be detected in the intracellular space within 5 min after its addition to the cell culture. Using flow cytometry technique, penetration kinetics of the labeled peptide into K-562 cells (at nontoxic micromolar concentrations) has been studied. We have observed a rapid internalization of the peptide to the target cells, thus confirming the results of microscopic analysis, i.e, the labeled acipensin was detectable in K-562 cells as soon as wihin 2-3 seconds after its addition to the incubation medium. The maximum of fluorescence was reached within a period of approx. 45 seconds, with further “plateau” at the terms of >100 seconds following cell stimulation with the test compound. These data support the concept, that the antimicrobial peptides of innate immunity system possess the features of cell-penetrating peptides, and allow us to consider the studied sturgeon peptide a promising template for development of new drugs with increased ability to enter the cells implicated into pathological processes, and, therefore, higher therapeutic efficiency

URANIUM SORPTION BY VINYLPYRIDINE ANION-EXCHANGER FROM SULPHATE-CHLORIDE SOLUTIONS

The sorption of uranium and chloride-ions from technological sulphate-chloride in-situ leaching solutions by vinylpyridine anion-exchanger VPAE was investigated. Values of dynamic exchange capacity at full resin saturation were 23,86 kg U m-3 and 20,47 kg Cl m-3