Biomedical subjects
Publications and source records attributed to V Ivanova.
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Studied was the dynamics of the changes taking place in the activity of a number of enzymes in the blood plasma (glutamate oxalacetate transaminase (GOT), glutamate pyruvate transaminase (GPT), lactate dehydrogenase (LDH), alkaline phosphatase (AP), aldolase (ALD), creatine phosphokinase (CPK), guanase, and cholinesterase (CE). The calculation of the correlation coefficients and the regression lines revealed that GOT, GPT, LDH, ALD, and guanase raised their activity following treatment of the test animals up to a higher extent and at a higher rate. Lower rate changes were those in the activity of AP, leucinaminopeptidase, and CE. No changes whatever were found in the activity of CPK. On the basis of these results the diagnostic value is determined of both the individual enzymes and the enzyme constellation as a whole.
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Some chemical and physiochemical properties of H-antigen, obtained through immunoabsorption, were studied. By applying the method of Davis, during a disc electrophoresis in a polyacrylic amide gel, it was proved that the molecule of flagellin is homogenous and is built up of only one polypeptic chain. On the other hand, by applying Weber's and Osborn's method, it was proved that flagellin is a protein having a molecular weight of about 53000 daltons. It showed its isoelectric point at pH 5.2, proved through Heil's and Zillig's method on strips of acetate cellulose (cellogel). The investigated aminoacidic composition showed the presence of 15 aminoacids wtih an approximative succession and a relative quantity of the separate aminoacids common to the flagellins of the different representatives of the genus Salmonella. No presence of cysteine, tryptophan, methionine and sigma-N-methylated lysin, were proved.
OH-antiserum was first produced in rabbit immunization with Salmonella abortus ovis cultures and was later used for obtaining an immunoadsorbent after the method of Avrameas and Thernynck. The raw (not purified) H-antigen produced after the method of McCoy et al., was purified by the immunoadsorbent and its activity and specificity were studied serologically by the reaction of Ouchterlony. It was established that the antigen reacts with the anti-H-salmonella serum, but does not react with normal sheep serum, which is an indication that it is purified and active. It was established also that immunoadsorption is a method suitable for H-antigen production from bacterial cilia.
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Sixty products, derived from marine organisms, typical of the Bulgarian Black Sea coast, were examined for inhibitory activity on the reproduction of influenza viruses in tissue cultures. The antiviral effect was investigated by the reduction of virus infectivity. Using representative strains of influenza virus it was shown that apparently the inhibitory effect was strain-specific. The most effective products were further studied in fertile hen's eggs and in experimental influenza infection in white mice.
The producing strain Streptomyces sp. 1010 was isolated from a shallow sea sediment from the region of Livingston Island, Antarctica. From the culture broth of this strain naturally active secondary metabolites were isolated identical to phthalic acid diethyl ester (C12H14O4, MW. 222); 1, 3-bis (3-phenoxyphenoxy)benzene (C30H22O4, MW.446); hexanedioic acid dioctyl ester (C22H42O4, MW.370) and the new substance 2-amino- 9, 13 -dimethyl heptadecanoic acid (C19H39NO2, MW.313). These compounds represent diverse classes of chemical structures and provide evidence for the untapped biosynthetic potential of marine bacteria from Antarctica.
Inulinase and Invertase Activities, Thermophilic Bacilli, Enzyme Thermostability Enzyme production of newly isolated thermophilic inulin-degrading Bacillus sp. 11 strain was studied by batch cultivation in a fermentor. The achieved inulinase and invertase activities after a short growth time (4.25 h) were similar or higher compared to those reported for other mesophilic aerobic or anaerobic thermophilic bacterial producers and yeasts. The investigated enzyme belonged to the exo-type inulinases and splitted-off inulin, sucrose and raffinose. It could be used at temperatures above 65 degrees C and pH range 5.5-7.5. The obtained crude enzyme preparation possessed high thermostability. The residual inulinase and invertase activities were 92-98% after pretreatment at 65 degrees C for 60 min in the presence of substrate inulin.