Isolation and immunochemical study of monomer and dimer forms of IgA human globulins]

Monomer and dimer of myeloma IgA human globulins are isolated by means of electrophoresis, ionic exchange chromatography, gel filtration and immunoadsorbtion. They are shown to be homogenous (using analytical ultracentrifugation and immunochemical analysis) and to differ in their antigenic specificity. Dimeric form of IgA has additional antigenic determinants, which depend on the intactness of a polymer structure and which are destroyed after protein dissociation into subunits in the presence of beta-mercaptoethanol. Reconstructed polymers are polydispersed subunit aggregates, they do not have polymeric determinants inherent to native polymers.     

Micro-autotransplantation of the skin. Changes in size and morphology of neo-skin

A new technique of wide wound skin epithelialization by free transplantation of autologous skin fragments 1 mm2 in size is demonstrated. The experiments were carried out on strainless rats of different age, 100 per cent epithelialization of wound 5 mm2 in grafting skin micro-autotransplantation (MATR) was observed. The primary effectiveness of wound closing square to MATR square was 1:20. However, as a result of wound contraction the effectiveness (on neo-epidermis square) was finally 1:15 in old rats. During histological analysis hyperplasia of the epidermis was marked and decreased gradually. Skin MATR method is considered as organ-typical culture in vivo.     

Metalloporphyrins and molecular complexes of amino acids with porphyrins in juvenile volcanic ash

In samples of juvenile ash of the volcano Tjatja, USSR (that erupted in 1973) metalloporphyrins were found. With respect to the fluorescence spectra free bases of the compounds were close to the pigments that formed in abiogenic synthesis experiments (predominance of long-wave length fluorescence band). The pigments detected occurred in the ash as molecular complexes with amino acids which seem to be of abiogenic origin. These findings are of interest in terms of exploration of the processes of chemical evolution and emergence of life on the Earth.     

Procedure for isolating nisin from Streptococcus lactis

The paper describes a method for obtaining the antibiotic nisine from Streptococcus lactis str. MSU via 50% acetic acid extraction. The concentrate is dried in the Anhydro spray drier (Denmark). The preparation is inactivated during a one-year storage in the refrigerator by 20-25%.     

Actinomyces thermovulgaris endospores

It has been established for the first time that autolysis observed when Actinomyces thermovulgaris T-54 is cultivated on liquid media of various composition is caused by the formation of submerged spores. These, in contrast to exospores of the majority of the actinomycetes, are endospores according to their structure and the following criteria: thermostability, the presence of dipicolinic acid, the structure of ultrathin cross-sections studied by electron microscopy, the resistance to novobiocin.     

Use of the method of protoplast fusion in the selection of a nisin producer

Experimental data on selection of Streptococcus lactis producing the polypeptide antibiotic nisin with the method of protoplast fusing, one of the modern methods of cell engineering are presented. Four strains of Streptococcus lactis differing in their nisin-producing levels and difficult for protoplasting were used in the study. It was shown possible to transfer them to the protoplast form when respective conditions for their preliminary cultivation and regeneration are provided. Distinctive features of these strains with respect to the antibiotic resistance, sugar fermentation and growth component requirements were revealed. The protoplast fusing yielded hybrids differing from the parent strains by a number of phenotypical features and nisin-synthesizing activity.