The SNCA-Rep1 Polymorphic Locus: Association with the Risk of Parkinson's Disease and SNCA Gene Methylation.

Neurodegeneration in Parkinson's disease is characterized by the accumulation of alpha-synuclein, a protein encoded by the SNCA gene, in neurons. In addition to mutations, many polymorphisms have been identified in this gene, and one of these is a dinucleotide microsatellite: SNCA-Rep1. The mechanisms by which specific configurations of SNCA-Rep1 may contribute to the development of this disease have yet to be clarified. In our study, a relationship between long SNCA-Rep1 alleles and Parkinson's was confirmed in the Russian population. Long allelic variants of SNCA-Rep1 were shown to be associated with the hypomethylation of the CpG-sites in intron 1 of the SNCA gene. Long variants of SNCA-Rep1 are supposed to exert their effect through the hypomethylation of a transcriptionally significant region of this gene. Hypomethylation is usually associated with increased expression, which, in turn, contributes to alpha-synuclein accumulation in neuronal cytoplasm, with the latter being the main molecular marker of Parkinson's disease. Further studies are needed to establish a relationship between our finding and SNCA gene expression.

[Lipid pores and life time of lipid bilayer membranes in gel and liquid crystal states]. / Lipidnye pory i vremena zhizni bisloinykh lipidnykh membran v gel'- i zhidkokristallicheskom sostoianiiakh.

The lifetime of lipid bilayer membranes formed from hydrogenated egg lecithin has been studied at the phase transition from liquid crystalline state to the gel. It was shown the lowering of the membrane stability at the phase transition temperature of hydrogenated egg lecithin. Using lifetime values and measured surface tension of bilayer the critical radius of transmembrane pore has been evaluated in comparison with experimental data, obtained by transmembrane current fluctuation registration. It was shown that lifetimes of bilayer lipid membrane in gel state conform data, derived from Deryagin-Gutop-Prokhorov's theory. The radii of pores corresponded to maximal transmembrane current fluctuations are close to critical values of pores in the gel state.

[Formation of stabile cupola-like lipid bilayer membranes with a mobile plateau Gibbs boundary]. / Formirovanie stabil'nykh kupoloobraznykh bisloinykh lipidnykh membran s podvizhnoi granitsei plato-Gibbsa.

Stable bilayer lipid membrane with mobile Platear-Gibbs border have been formed. The predominant condition of the formation is the presence of lipid coverage on the teflon surface near the hole. The formation process includes transformation of the initial planar lipid bilayer into cupola-shaped one by bowing of the lipid bilayer due to hydrostatic pressure, movement of the PGb along the teflon surface. The bilayer area estimated by electric capacitance increases from 0.1 x 10(-8) F to 21 x 10(-8) F. Electric conductance of the lipid bilayer has not changed except for the phase transition and membrane collapse. The electric capacitance of the BLM formed from hydrogenated egg lecithin was changed by cooling between 60 degrees and 40 degrees C with the maximum at about phase transition range. The individual membrane sustains several scannings of the temperature without disruption which is an evidence of the stability of the cupola-shaped membranes.