DNA conformation on surfaces measured by fluorescence self-interference.

The conformation of DNA molecules tethered to the surface of a microarray may significantly affect the efficiency of hybridization. Although a number of methods have been applied to determine the structure of the DNA layer, they are not very sensitive to variations in the shape of DNA molecules. Here we describe the application of an interferometric technique called spectral self-interference fluorescence microscopy to the precise measurement of the average location of a fluorescent label in a DNA layer relative to the surface and thus determine specific information on the conformation of the surface-bound DNA molecules.

Synthesis of aminoacyl adenylates and their role in abiogenic peptide synthesis.

Preparative synthesis of adenylates of amino acids with modifications of Meister's method, pertaining to the purification and identification of the reaction products, is described. The significance of the synthesized substances is discussed in connection with the problem of abiogenic synthesis of peptides.

[Principles of collecting the material for morphological and morphometric studies in pathology].

Methods of random sampling of preparations for investigation of pathological processes of diffuse and focal character are described; a possible classification of pathologoanatomic material is suggested. It is recommended to consider the total volume of an organ as a combination of submultitudes of elementary volumes non-intersected in pairs; these volumes should be selected according to the table of random numbers. For this purpose, the organ is dissected in parallel blocks of a given thickness perpendiculary to its root and on the last block a lattice is placed with numbered squares giving numeration for submultitudes of elementary volumes.