African trypanosomes are capable of both pyrimidine biosynthesis and salvage of preformed pyrimidines from the host. However, uptake of pyrimidines in bloodstream form trypanosomes has not been investigated, making it difficult to judge the relative importance of salvage and synthesis or to design a pyrimidine-based chemotherapy. Detailed characterization of pyrimidine transport activities in b...

An efficient and mild synthesis of quinoxalines in cludingcyclo-condensation of 1, 2-phenylenediamine and 1, 2-diketonesin the presence of1mol% catalytic amount of SnO2 nanoparticles (1 mol%) in water at room temperature is established. On the whole, this study introduced at this point is substantial in terms of using water as solvent, low reaction time (5 to 10 minutes), high yields...

The K562 Chronic Myeloid Leukaemia Cell Line undergoes Apoptosis in Response to 4-chloro-5-iodo-7H-pyrrolo[2.3-d]pyrimidine

The catalysis, by the enzyme thiaminase, of reversible baseexchange reactions between thiamine and aromatic tertiary amines was first reported by Fujita et al. (1). Related findings with mammalian diphosphopyridine nucleotidases (2) and with methionine activation (3) drew attention to the energy-rich nature of “onium” (4-6) compounds and suggested that the alkylation of thiazole must involve ac...

Novel N-methoxymethylated (MOM) pyrimidine (4-13) and pyrimidine-2,4-diones (15-17) nucleoside mimetics in which an isobutyl side-chain is attached at the C-6 position of the pyrimidine moiety were synthesized. Synthetic methods via O-persilylated or N-anionic uracil derivatives have been evaluated for the synthesis of N-1- and/or N-3-MOM pyrimidine derivatives with C-6 acyclic side-chains. A s...

Humans are exposed to various organic peroxides through chemical, pharmaceutical and cosmetic products. On photolysis, these peroxides produce alkoxyl radicals and hydroxyl radicals. The reaction of *OH radicals with DNA and its constituents have been extensively studied, but very little is known about the reactions of alkoxyl radicals with DNA and its constituents. In view of this, the oxidati...

Experiments have been carried out with Neurospora which demonstrate that the quantitatively important route for the biosynthesis of the pyrimidine deoxyribonucleosides in the DNA* of this organism involves the entire carbon skeleton of a pyrimidine ribonucleoside. A very high labeling of the pyrimidine nucleosides of the RNA and DNA was brought about by feeding uniformly labeled CY4-cytidine to...

UV inactivation, photoreactivation, and dark repair of Escherichia coli and Cryptosporidium parvum were investigated with the endonuclease sensitive site (ESS) assay, which can determine UV-induced pyrimidine dimers in the genomic DNA of microorganisms. In a 99.9% inactivation of E. coli, high correlation was observed between the dose of UV irradiation and the number of pyrimidine dimers induce...