Search

Screening of producers of alpha-N-acetylgalactosaminidase among 854 strains of micromycetes, 171 yeast and 357 bacterial cultures has been carried out. A capacity to synthesize the enzyme was revealed in 11% of cultures. Representatives of Aspergillus genus (activity--0.11-0.142 un./ml) were most active in producing the enzyme. It has been established that glucosidases spectrum in the culture liquid of 18 most active strains was characterized by complete homogeneity and by the presence of a rather high level (0.5-0.9 un./ml) of alpha-galactosidase activity. Complex preparations of alpha-N-acetylgalactosaminidase and alpha-galactosidase have been obtained from the culture liquid of producers by fractionation by ammonium sulphate (30 and 90% saturation); their pH- and thermo-optimum, pH- and thermal stability have been studied. It was shown possibility to induce alpha-N-acetylgalactosaminidase synthesis by a number of carbohydrates (galactose, glucose, galactosamine, and glucosamine), complex-forming substances (guanidine HCl), nitroaminoguanidin and guanidine carbonate and bovine blood. As a result the strain of Aspergillus niger 185 III was chosen which activity level could be increased more than 3 times (activity--0.6 un./ml as compared to initial one).

We describe here a new method of measuring quantitative parameters of erythrocyte deformability by automated analysis of images obtained using an erythrocyte deformation device, allowing fixation with glutaraldehyde directly within the shear flow. The method for measuring erythrocyte deformability includes capture of images from the device for erythrocyte deformation in shear flow and automatic image analysis, including preprocessing, binarization, identification of objects on images, and counting of the numbers of objects by approximating the objects of interest to ellipses. Processing yielded a coefficient of deformability for each erythrocyte, along with statistical indicators: the distribution function, mean deformability, dispersion, and the coefficient of asymmetry. This method provides assessment of the distribution of erythrocytes by deformability and, thus, additional diagnostic and scientific information; the accuracy of assessments of erythrocyte deformability is increased. [ABSTRACT FROM AUTHOR]

The kinetics of nitrogen oxide release by binuclear dinitrosyl iron complexes (B-DNICs) with thiolate ligands based on thiophenol and its several oxy, amino, and nitro derivatives was studied using a suspension of red blood cells simulating the internal medium of a blood vessel. The NO donating ability of the complexes was estimated by the kinetic parameters of first-order equation, which described the formation of intra-erythrocytic methemoglobin. Three typical kinetic profiles of NO donation were distinguished: pseudosaturation donation and donation with prolonged and explosive profiles. In the case of first-type NO donation typical of complexes with thiophenol and its nitro derivatives, the curves display a fast coming to saturation long before the complete release of all NO groups contained in the structure of the starting complex into a solution. Such a type of donation is likely due to the formation of long-lived nitrosyl intermediates in the system. The prolonged type of NO donation shown by the complex with hydroxyphenyl ligand is characterized by virtually constant rate of NO release into a solution without pronounced transition to saturation during experiment (10–12 min). In the case of explosive-type donation characteristic of the complex with aminophenyl ligands, a considerable portion of NO was fast released into a solution within 1–3 min. All complexes under study caused hemolysis of a 0.2% suspension of red blood cells. The complex with aminophenyl ligands exhibited the highest hemolytic activity. [ABSTRACT FROM AUTHOR]

The NO-donating and hemolytic activity of the binuclear tetranitrosyl iron complexes (TNIC) with thiolate ligands of the composition [Fe(SR)(NO)], where R is pyridin-2-yl and 5-nitropyridin-2-yl, was studied. The NO-donating and hemolytic activities of the com- plex with the nitrosubstituted ligand are approximately two and three times higher than the corresponding characteristics of the complex with unsubstituted 2-mercaptopyridine, respectively. Symbate changes in these parameters confirm the conclusion made earlier on the peroxynitrite-dependent mechanism of erythrocyte hemolysis under the action of TNIC. The NO-donating activity of TNIC with ligands of the 2-mercaptopyridine series, unlike the previously studied complexes containing thioderivatives of other nitrogenous heterocycles as S-ligands, did not decrease with an increase in the concentration of erythrocytes. This allows one to consider them as promising NO-donating substances for the preparation of pharma- cological remedies. [ABSTRACT FROM AUTHOR]