The main pigment of the dormant Mycobacterium smegmatis is porphyrin.

Upon transition of Mycobacterium smegmatis into the dormant state, accumulation of a dark brown fluorescent pigment was observed. This pigment gave bright red fluorescence in both cells and the culture medium. Based on 1H-NMR, MALDI and UV spectra, the fluorescent compounds, extracted from the culture medium as well as from the dormant cells, were concluded to be a mixture of free coproporphyrin III and uroporphyrin III and their corresponding methyl esters. A possible significance of porphyrin pigment accumulation in the dormant cells is discussed.

[Affect of deoxynojirimycin derivatives on hepatitis C virus morphogenesis].

Viral hepatitis C is one of the wide-spread and dangerous human diseases. The choice of drugs for treatment of chronic hepatitis C virus (HCV) infection is limited and prophylactic vaccines do not exist. Thus, the development of new antiviral strategies and substances are of great importance. The targeting of viral morphogenesis might be used as an alternative approach to existing strategies of HCV blocking. The glycosylation of viral envelope proteins is an important step of viral particle morphogenesis that determines the correct assembly of HCV virions. The derivatives of glucose analog deoxynojirimycin (DNJ)--inhibitors of alpha-glucosidase can impair the assembly of structural proteins and HCV particle formation. In the present work the affect of alkylated derivatives of DNJ N-pentyl-DNJ and N-benzyl-DNJ to HCVmorphogenesis in a model system insect cells producing three viral structural proteins with formation of virus-like particles was studied. Intracellular N-glycosylation of HCV envelope glycoproteins was shown to be impaired by DNJ derivatives. At 1 mM concentrations of these substances the level of gpE1 and gpE2 glycoproteins increase and their electrophoretic mobility decrease which seems to be due to inhibition of a-glucosidase in endoplasmic reticulum and accumulation of hyperglycosylated N-glycans in HCV glycoproteins. The interaction of the latters with calnexin leads to formation of unproductive dimers and bloks productive assembly of virus-like particles.

Influence of oxidative and nitrosative stress on accumulation of diphosphate intermediates of the non-mevalonate pathway of isoprenoid biosynthesis in corynebacteria and mycobacteria.

Artificial generation of oxygen superoxide radicals in actively growing cultures of Mycobacterium tuberculosis, Myc. smegmatis, and Corynebacterium ammoniagenes is followed by accumulation in the bacterial cells of substantial amounts of 2-C-methyl-D-erythritol-2,4-cyclodiphosphate (MEcDP) - an intermediate of the non-mevalonate pathway of isoprenoid biosynthesis (MEP) - most possibly due to the interaction of the oxygen radicals with the 4Fe-4S group in the active center and inhibition of the enzyme (E)-4-oxy-3-methylbut-2-enyl diphosphate synthase (IspG). Cadmium ions known to inhibit IspG enzyme in chloroplasts (Rivasseau, C., Seemann, M., Boisson, A. M., Streb, P., Gout, E., Douce, R., Rohmer, M., and Bligny, R. (2009) Plant Cell Environ., 32, 82-92), when added to culture of Myc. smegmatis, substantially increase accumulation of MEcDP induced by oxidative stress with no accumulation of other organic phosphate intermediates in the cell. Corynebacterium ammoniagenes'', well-known for its ability to synthesize large amounts of MEcDP, was also shown to accumulate this unique cyclodiphosphate in actively growing culture when NO at low concentration is artificially generated in the medium. A possible role of the MEP-pathway of isoprenoid biosynthesis and a role of its central intermediate MEcDP in bacterial response to nitrosative and oxidative stress is discussed.

[A uniform approach to the synthesis of carbohydrate conjugates of polyhedral boron compounds as potential agents for boron neutron capture therapy].

A uniform approach to the synthesis of carbohydrate conjugates with polyhedral boron compounds (PBCs) was developed. Oligosaccharide derivatives with an aglycone moiety amino group can be coupled with PBC carboxyl derivatives using N-methyl-N-(4,6-dimethoxy-1,3,5-triazin-2-yl)morpholinium chloride as a coupling agent. Both N- and O-glycosides differing in the conformational mobility around the glycoside bond were shown to be useful as oligosaccharides with a functional group in the aglycone moiety. This allows the application of this approach to the synthesis of PBC conjugates with a wide range of oligosaccharides. For example, not only oligosaccharides obtained by chemical synthesis but also reducing oligosaccharides isolated from natural sources can be transformed into N-glycosides. The approach was tested by the example of conjugation of the carboxyl derivatives of ortho-carborane and dodecaborate anion with lactose as a model oligosaccharide. Lactose, an easily available disaccharide, is a ligand for lectins expressed on the surface of melanoma cells. The approach suggested is the first example of the synthesis of such conjugates that does not require protective groups for the carbohydrate residue. It is especially important for obtaining dodecaborate-carbohydrate conjugates for which the removal of protective groups is often a non-trivial task.