[alphaC domains of fibrinogen molecules as the structures accelerating fibrin assembly]. / alphaC-domeny molekuly fibrinogena kak struktury, uskoriaiushchie samosborku fibrina.

Preparation of monomeric fibrin lacking intact alpha C-domains (monomeric X1-fragment), but fully clottable, is described. The assembly process of both monomeric fibrin and monomeric X1-fragment has been studied by electron microscopy and light scattering methods. It was shown that both proteins form similar fibrils with characteristic cross-banding. Upon dilution a sharp elevation of the differences between the assembly rates of monomeric X1-fragment and monomeric fibrin was revealed. The results obtained show that alpha C-domains take part in fibrin clot formation not as structural components but as the factor accelerating the ordered assembly of complex fibrin structure. The possible mechanism of alpha C-domains participation in fibrin clot formation are regarded.

[Electron microscopic study of the DNA products of reverse transcription]. / Elektronno-mikroskopicheskoe issledovanie DNK-produktov obratnoi transkriptsii.

DNA-products synthesized on pre-mRNA's from rat liver and rabbit erythroidal bone marrow cells, on rabbit globin mRNA and the RNA-templates themselves have been examined by electron microscopy. In spreading conditions providing extension of molecules the sizes of DNA-products corresponded to sizes of RNA templates. Globin mRNA, pre-mRNA as well as cDNA synthesized on these templates in the presence of actinomycine D were seen as single-stranded molecules by electron microscopy. The preparations of cDNA synthesized in the absence of actinomycine D on the pre-mRNA template were represented by double-stranded molecules along side with sigle-sranded. Up to 10% of double-stranded DNA-product appeared to be branched; all branches of such molecules had the thickness and rigidity of double-stranded structures. The possible ways of formation of branched structures are discussed.

[Electron microscopy study of fibrin self-assembly]. / Elektronno-mikroskopicheskoe issledovanie samosborki fibrina.

The process of fibrin selfassembly has been examined by electron microscopy. Its initial stage is found to consist in fibrin monomer conversion to thin filaments of random shape, probably identical with the well known intermediate polymers of fibrin. When the filaments attain an appropriate size they arrange themselfs into bundles with increasingly ordered structure. At this stage a tendency to form cross bands appears. The cross-band system develops on the basis of substance redistribution within fibrin molecules incorporated into filamentous bundles. It seems hardly warranted to call the complicated process of fibrin fibre formation as "selfassembly". This process represents a "molecular morphopoesis" and includes: selfassembly of filaments; selfassembly of bundles and transformation leading to the establishment of the ultimate fibril structure.