Analogues of Pyrimidine Nucleosides as Mycobacteria Growth Inhibitors.

Tuberculosis (TB) is the oldest human infection disease. Mortality from TB significantly decreased in the 20th century, because of vaccination and the widespread use of antibiotics. However, about a third of the world's population is currently infected with Mycobacterium tuberculosis (Mtb) and the death rate from TB is about 1.4-2 million people per year. In the second half of the 20th century, new extensively multidrug-resistant strains of Mtb were identified, which are steadily increasing among TB patients. Therefore, there is an urgent need to develop new anti-TB drugs, which remains one of the priorities of pharmacology and medicinal chemistry. The antimycobacterial activity of nucleoside derivatives and analogues was revealed not so long ago, and a lot of studies on their antibacterial properties have been published. Despite the fact that there are no clinically used drugs based on nucleoside analogues, some progress has been made in this area. This review summarizes current research in the field of the design and study of inhibitors of mycobacteria, primarily Mtb.

Photosensitized oxidation by dioxygen as the base for drinking water disinfection.

Efficiencies of the series water-soluble anionic and cationic sensitizers have been studied in photodynamic natural water disinfection. It was found that only cationic sensitizers are efficient in photooxidative bacteria killing during photodynamic water treatment. The difference in photodynamic action towards different groups of microorganisms has been observed. The most vulnerable are enterococcus and enterococcus faecalis. Spores of sulfite-reducing clostridium are resistant to photodynamic action but, to provide drinking water, clostridium may be removed by sedimentation and filtration. The dependence of photodisinfection on treatment conditions was studied. It was found that sunlight along with artificial visible light sources may be used for photodynamic water treatment. The photodynamic step, arranged with artificial visible light source, was included in a process of conventional water purification instead of chlorine disinfection. Preliminary pilot testing have shown that photodynamic water disinfection in combination with coagulation, sedimentation, sand and carbon filtrations (latter-to remove sensitizer and products of its photolysis) provides water of high quality, free of bacteria and chemicals as well.