Identif ication of duplicate accessions in the sweet maize collection by means of zein electrophoresis.

Of all the subspecies of Zea mays L. cultivated in the world, sweet maize is the most important for the global economy. The leading seed-growing companies and research institutions around the world are engaged in breeding this crop. To meet the increasing demands of the industry to grain quality, it is important to select appropriate local varieties and lines for hybridization. Local (usually heterogeneous) varieties are a valuable source material for creating self-pollinated lines that contribute to a significant broadening of the genetic base of parental forms used in breeding. The advantages of sweet maize varieties and the interest of the food industry in them make it possible to consider accessions from the maize collection of the N.I. Vavilov Institute (VIR) as a potentially valuable source material for breeding. The present research concentrated on 19 local sweet maize varieties with different grain colors from the VIR collection, that is, 9 varieties with the blue color of ripe grain, 4 with white (colorless) grain, 3 with yellow, and 3 with red. The research included an analysis of zein electrophoretic patterns (protein markers); a study of their biotype composition and the nature of genetic polymorphism, as well as the creation of a protein pattern database for each accession. For a series of accessions with the same varietal name, but different catalog numbers, the degree of their identity was determined from their biotype composition in order to exclude duplication. Zein electrophoresis was carried out in vertical plates of 10 % polyacrylamide gel according to the standard ISTA technique developed with the participation of the Biochemistry and Molecular Biology Department of VIR. Zein patterns were used for the first time to electrophoretically study sweet maize varieties with different grain colors. Unique zein patterns were established for all the accessions studied, which makes possible their identification by specific marker components. The results of this work characterize zein electrophoresis as a useful tool for the identification and registration of duplicate accessions in the VIR collection of sweet maize varieties.

[Chiral safety of the biosphere as a biophysical problem]. / Khiral'naia bezopastnost' biosfery kak biofizicheskaia problema.

The biosphere with its inherent chiral asymmetry fixed in the process of biological evolution at the level of L-amino acids and D-hydrocarbons and some other biologically active compounds of biogenic origin is under strong pressure of chiral substances produced by chemical, pharmaceutical, and other branches of industry and agriculture. Effective use of enantiomers is accompanied by toxic and even mutagenic effects of their mirror-image enantiomorphs. Only small amounts of products are tested for chiral purity; there is no system of global biosphere monitoring as well as no common standards of permissible concenrations. The investigation of the molecular basis of chiral stereospecificity of enzymes and cell receptors is of great interest from the point of view of fundamental biophysics. On the other hand, the development of chiral-selective sensors for environmental monitoring is important from the viewpoint of applied biophysics.

[Isolation and purification of plant histones]. / Vydelenie i ochistka gistonov rastenii.

A fractionation pattern for isolation and identification of histones, allowing to obtain preparative amounts of individual histone fractions, is proposed. The obtained fractions were identified by their solubility, by differential staining and by electrophoresis. The fractionation resulted in all major histone fractions of wheat, rye, cotton, pea and calf thymus. The electrophoretic patterns of all plant histones were identical, differing only in their histone H1 contents. The histone fraction H1 was also found to be heterogeneous, which, with the exception of cotton H1 fraction, was more pronounced than in the case of calf thymus. The data obtained can be interpreted in terms of the functional role of histones in the genetic mechanism of plants and a possible use of individual fractions and components of histones for the study of phylogenetic relationships between the species.