[Radiation-induced changes in the genome of pine seeds, forming under conditions of chronic irradiation in the Chernobyl exclusion zone]. / Radiatsionno-indutsirovannye izmeneniia v genome semian sosny, sformirovabshikhsiia v usloviiakh khronicheskogo oblucheniia v zone otchuzhdeniia ChAES.

Comparative study of long-term existing genome damages in the chronically irradiated pine seeds from different parts of Chernobyl zone have been performed by a pulsed field gel electrophoresis and hydroxyapatite chromatography. Some differences were established for DNA degradation kinetic from protoplasts with various accumulated doses of irradiation. Results obtained could testify the existence of long-living changes in the experimental plants genome.

Binding of small acid-soluble spore proteins from Bacillus subtilis changes the conformation of DNA from B to A.

Small acid-soluble spore proteins (SASPs) appear 3-4 hr after the onset of sporulation in Gram-positive bacteria and constitute up to 20% of the protein of mature spores. Previous studies using Bacillus subtilis deletion mutants lacking SASP-alpha and -beta have shown that such mutations abolish the elevated resistance of spores to UV radiation. Analyses using circular dichroism and Fourier-transform infrared spectroscopy now demonstrate that binding alpha/beta-type SASPs to DNA in vitro causes a structural change in DNA, from the B to the A conformation. This may provide the basis whereby alpha/beta-type SASPs confer increased spore UV resistance in vivo--by changing spore DNA conformation, they alter DNA photochemistry such that UV irradiation produces spore photoproduct instead of the more lethal cyclobutane-type thymine dimers.