Bacillus subtilis var. amyloliquefaciens biosynthesis of extracellular protease possessing coagulase activity and formed under conditions of limiting the nitrogen sources in the medium

An exocellular protease having the activity of coagulase was synthesized by Bacillus subtilis var. amyloliquefaciens when the growth medium contained no nitrogen sources. The removal of a nitrogen source from the medium was found to induce the synthesis of exoproteases by washed bacterial cells. Protein as a sole source of nitrogen in the medium inhibited rather than induced the biosynthesis of proteases possessing the activity of coagulase by the cells. The production of exoproteases with the coagulase activity was inhibited when a mixture of amino acids was used as a sole nitrogen source.     

Buckwheat trypsin inhibitor with helical hairpin structure belongs to a new family of plant defence peptides

A new peptide trypsin inhibitor named BWI-2c was obtained from buckwheat (Fagopyrum esculentum) seeds by sequential affinity, ion exchange and reversed-phase chromatography. The peptide was sequenced and found to contain 41 amino acid residues, with four cysteine residues involved in two intramolecular disulfide bonds. Recombinant BWI-2c identical to the natural peptide was produced in Escherichia coli in a form of a cleavable fusion with thioredoxin. The 3D (three-dimensional) structure of the peptide in solution was determined by NMR spectroscopy, revealing two antiparallel α-helices stapled by disulfide bonds. Together with VhTI, a trypsin inhibitor from veronica (Veronica hederifolia), BWI-2c represents a new family of protease inhibitors with an unusual α-helical hairpin fold. The linker sequence between the helices represents the so-called trypsin inhibitory loop responsible for direct binding to the active site of the enzyme that cleaves BWI-2c at the functionally important residue Arg(19). The inhibition constant was determined for BWI-2c against trypsin (1.7×10(-1)0 M), and the peptide was tested on other enzymes, including those from various insect digestive systems, revealing high selectivity to trypsin-like proteases. Structural similarity shared by BWI-2c, VhTI and several other plant defence peptides leads to the acknowledgement of a new widespread family of plant peptides termed α-hairpinins.     

Streptomyces spheroides mutant deprepressed for exoprotease biosynthesis

The effect of carbon, nitrogen and sulfur sources on the biosynthesis of exoproteases was studied with the parent Streptomyces spheroides strain 35 and its mutant M8-2. Addition of a carbon, nitrogen and sulfur source to the medium deficient in one of these elements did not repress the synthesis of exoproteases by the washed mycelium of the mutant as compared to the parent strain. Protein as a sole source of carbon, nitrogen and sulfur had no effect on the biosynthesis of exoproteases by the mutant. In contrast to the parent strain, the biosynthesis of exoproteases in the mutant was not controlled by metabolite repression.     

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.