Safeguarding HIV prevention and care services amidst military conflict: experiences from Ukraine.

Ukraine stands out among European countries concerning HIV epidemiological data. Since February 2022, the military conflict with Russian forces has posed unprecedented challenges to HIV prevention and care. AIDS Healthcare Foundation (AHF), a global non-profit organisation with operations in Ukraine since 2009, implemented a preparedness plan to protect staff members and support local facilities in the continuity of care throughout the war.

Derivatization and template-guided ligation of oligodeoxyribonucleotides using cyanogen bromide and N-substituted morpholines.

Cyanogen bromide has been found to induce the template-guided condensation of oligonucleotides only in the presence of N-substituted morpholines. Based on 31P, 1H and 13C NMR spectroscopy data, the mechanism of the phosphomonoester group activation by cyanogen bromide in N-substituted morpholine buffers is suggested. It has also been shown that BrCN can be used for the synthesis of oligonucleotide derivatives in aqueous solution.

Targeting of single-stranded DNA and RNA containing adjacent pyrimidine and purine tracts by triple helix formation with circular and clamp oligonucleotides.

The aim of this work was to construct an anti-messenger targeted to the pim-1 oncogene transcript, based on circular or clamp oligodeoxyribonucleotides. The formation of bimolecular triplexes by clamp or circular oligonucleotides was investigated using single-stranded targets of both DNA (5'-CCCTCCTTTGAAGAA-3') and RNA type (5'-CCCUCCUUUGAAGAA-3'). The third, 'Hoogsteen' strand of the triplex was represented by G,T-rich sequences.

A model of EcoRII restriction endonuclease action: the active complex is most likely formed by one protein subunit and one DNA recognition site.

To elucidate the mechanism of interaction of restriction endonuclease EcoRII with DNA, we studied by native gel electrophoresis the binding of this endonuclease to a set of synthetic DNA-duplexes containing the modified or canonical recognition sequence 5'-d(CCA/TGG)-3'. All binding substrate or substrate analogues tested could be divided into two major groups: (i) duplexes that, at the interaction with endonuclease EcoRII, form two types of stable complexes on native gel in the absence of Mg2+ cofactor; (ii) duplexes that form only one type of complex, observed both in the presence and absence of Mg2+. Unlike the latter, duplexes under the first group can be hydrolyzed by endonuclease.