[Bacterial pigment prodigiosin and its genotoxic effects].

The prodigiosin preparation was isolated and purified from Serratia marcescens ATCC 9986, using chromatographic methods. The analysis of the preparation by TLC, NMR-spectrometry and mass-spectrometry allowed to confirm the red pigment fraction as the prodigiosin and detect its purity. Originally, the specific features of the toxic and genotoxic effects of prodigiosin and the possibility of induction of mutations by pigment in the cells of Salmonella typhimurium TA 100 (Ames test) and chromosome damage of mammalian erythroblasts have been determined.

[The receptor of serpentine type and the heterotrimeric G protein as targets of action of the polylysine dendrimers].

The molecular mechanisms of action of the polycationic peptides--polylysine homo- and heterodendrimers on functional activity of biogenic amines- and peptide hormones-sensitive adenylyl; cyclase signaling system (AC system) in the myocardium and the brain of rats were studied. These peptides are expected to be used as highly effective polymer carries for biologically active substances. The polylysine homodendrimers of the third [(NH2)16(Lys)8(Lys)4(Lys)2Lys-Ala-NH2] (I), fourth [(NH2)32(Lys)16(Lys)8(Lys)4(Lys)2Lys-Ala-NH2 (II) and fifth [(NH2)64(Lys)32(Lys)16(Lys)8(Lys)4(Lys)2Lys-Ala-NH2] (III) generations and the polylysine homodendrimers of fifth generation--[(NH2)64(Lys-Glu)32(Lys-Glu)16(Lys-Glu)8(Lys-Glu)4(Lys-Glu)2Lys-Ala-Ala-Lys (ClAc)-Ala-NH2] (IV), [(NH2)64(Lys-Ala)32(Lys-Ala)16(Lys-Ala)8(Lys-Ala)4(Lys-Ala)2Lys-Ala-Lys(ClAc)-Ala-Ala-NH2] (V) and [(NH2)64(Lys-Gly-Gly)32(Lys-Gly-Gly)16(Lys-Gly-Gly)8(Lys-Gly-Gly)4(Lys-Gly-Gly)2 Lys-Gly-Gly-Lys(ClAc)-Ala-Ala-NH2] (VI) showed receptor-independent mechanism of heterotrimeric G-proteins activity, preferably of inhibitory type, interacting with C-terminal regions of their alpha-subunits.

[Lysine dendrimers as vectors for delivering genetic constructs to eukaryotic cells].

Asymmetrical lysine dendrimers are promising as vectors for delivering gene expression constructs into mammalian cells. The condensing, protective, and transfection properties were studied for pentaspherical lysine dendrimer D5 and its analog D5C10, modified with capric acid residues at the outer sphere; in addition, the transfection activity was assayed for complexes DNA-dendrimer-endosomolytic peptide JTS-1. Fatty acid residues incorporated in lysine dendrimers proved to improve their ability to bind DNA, to protect DNA from nuclease degradation, and to ensure its transfer into the nucleus.

[Comparative study of molecular mechanisms of natural and synthetic polycationic peptides action on the activity of the adenylyl cyclase signaling system].

The molecular mechanisms of action of natural and synthetic polycationic peptides, forming amphiphilic helices, on the heterotrimeric G-proteins and enzyme adenylyl cyclase (AC), components of hormone-sensitive AC system, were studied. It is shown that synthetic peptides C-epsilonAhx-WKK(C10)-KKK(C10)-KKKK(C10)-YKK(C10)-KK (peptide I) and (GRGDSGRKKRRQRRRPPQ)2-K-epsilonAhx-C(Acm)(peptide II) in dose-dependent manner stimulate the basal AC activity, inhibit forskolin-stimulated AC activity and decrease both stimulating and inhibiting AC effects of the hormones in the tissues (brain striatum, heart muscle) of rat and in smooth muscles of the mollusc Anodonta cygnea. AC effects of these peptides are decreased after membrane treatment by cholera and pertussis toxins and are inhibited in the presence of the peptides, corresponding to C-terminal regions 385-394 alphas- and 346-355 alphai2-subunits of G-proteins.