Biomedical subjects
Publications and source records attributed to B Skoczylas.
The experiments performed in vitro have shown that DAPI and RNA form insoluble and indigestible complexes. This seems to explain the earlier observed retardation of drug accumulation in the nucleus of a living cell in the presence of RNA.
Macronuclei of Paramecium aurelia, isolated in 4% gum arabic, contain nearly exclusively heterochromatin which is unaccessible to DNA-dependent, bacterial RNA polymerase. Heterochromatin decondensation under tris-HCl treatment did not change its template accessibility, whereas selective removal of the basic proteins induced profound changes in ultrastructure of heterochromatin and increased its template activity. More intensive incorporation of H3-UMP was found after arginine rich histones removal. The relations between functional and morphological changes after various heterochromatin modification in macronuclei of Paramecium aurelia, a representative of lower eukariotes, are discussed and compared with those in higher eukariotes.
4',6-Dioarboxyamide-2-phenyl indole (DCI), a non-ionic structural analogue of 4',6-diamidine-2-phenyl indole.2HCl (DAPI), was synthesized in order to verify the hypothesis of intercalation of both dyes into the DNA double helix. The influence of pH, viscosity, and different concentrations of SDS (sodium dodecylsulphate) or NaCl on the optical and fluorescent properties and the changes in thermal transition of both dye complexes with DNA confirm the affinity of the dyes to the double helix as well as their stabilizing influence on the secondary DNA structure. The results of binding studies, carried out by fluorescent methods have shown that the dyes are strongly bound to DNA, though the number of binding sites is small. According to the experimental data, the fluorescent properties of DAPI and DCI complexes with DNA are connected with the intercalating binding mechanism of these dyes. On the other hand, the eventual ionic or hydrogen bonds of dyes outside the DNA helix do not change noticeably their fluorescent properties.
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