Biomedical subjects
Publications and source records attributed to B V Rozynov.
The formyl group transfer from N-formyl amino acids and their derivatives to other acceptors--amino acids esters and aniline, was studied. Formylamino acids with the free alpha-carboxyl group are more effective donors in transformylation than formyl peptides or esters of formylamino acids.
Details of a nitrocellulose (NC) substrate preparation technique in 252Cf plasma desorption time-of-flight mass spectrometry were investigated using an electrospray device, in which a micropump was employed for solution delivery. The molecular ion yields for three standard proteins (porcine insulin, chicken-egg lysozyme and chymotrypsinogen A) were studied as a function of the electrosprayed NC layer thickness, spray rate, NC solution concentration and some other parameters. Optimal parameters of the NC substrate preparation procedure were determined, which include deposition of a layer of 250-750 micrograms cm-2 at up to 15 microliters min-1 spray rate and up to 15 micrograms microliters-1 solution concentration.
The influence of ganglioside GM3 and some of its breakdown products on phytohemagglutinin-induced blast transformation of human lymphocytes and concanavalin-A-induced T-suppressor activity was studied. The structures of two major hydrolysis products of GM3 were established by negative-ion fast-atom-bombardment mass spectrometry as neuraminyllactosylsphingosine (NeuLacSph) and neuraminyllactosylceramide (NeuLacCer). Both substances were shown to be potent inhibitors of mitogen-induced lymphoblastic transformation whereas their acetylation products NeuAcLacSphAc and GM3 did not affect the proliferative response of lymphocytes to phytohemagglutinin. On the other hand, only GM3 and NeuLacSph were able to enhance concanavalin-A-induced T-suppressor activity. On the basis of these data, it is suggested that the effects of GM3 and its breakdown products on lymphoblastic transformation and T-suppressor activity must rest on different mechanisms and that N-deacylation of GM3 appears to be an essential step in conversion of the ganglioside into an inhibitor of lymphocyte blast transformation.
Methyl, benzyl and diphenylmethyl esters of the glycopeptide antibiotic eremomycin were obtained by its treatment with corresponding diazoalkanes. The esters have high antibacterial activity but are less active than the parent antibiotic.
The data on UV, 1H NMR and mass spectroscopy confirmed that heliomycin produced by S. heliomycini and antibiotic 11-98 produced by S. olivocinereus were identical with resistomycin. The major minor component produced by S. heliomycini was shown to be resistoflavin which was also confirmed by physicochemical methods.
It is shown that mass-spectrometry with ammonia desorption chemical ionization (ADCI) can be used for identification of aminoglycosides and macrolides at the initial stages of screening. ADCI can also be used for selection of strains which form the lowest amounts of by-products, as well as for optimization of biosynthetic conditions.
Antimicrobial activity of partial degradation products of eremomycin, a new glycopeptide antibiotic, was studied. The products formed by eremomycin deglycosylation (deseremosaminyl eremomycin, eremosaminyl aglycone and aglycone) and elimination of the chlorine atom from the molecule aglycone moiety (dechloroeremomycin). The spectral data in favour of the compounds structure are presented. It was found that partial degradation led to a decrease in the antimicrobial activity of the antibiotic. Dechloreremomycin had the highest activity among the products. Its MIC for the methicillin-resistant strains of Staphylococcus aureus was only twice as low as that of the initial antibiotic.
Interaction of carbenicillin with kanamycin, gentamicin, tobramycin, and amikacin, as well as that of cefotaxime with the same aminoglycosides were studied. It was shown that carbenicillin inactivated aminoglycosides in a patient's plasma, urine, rH 5.3-8.44, and in buffer solutions, pH 3.7, 7.5 and 9.25. The inactivation level was the least in acid media. The mechanism of the inactivation was elucidated: opening of the carbenicillin beta-lactam ring occurred at the start.
Condensation of rubomycin (daunorubicin) with respective hydrazides yielded novel substituted hydrazones: 13-cyanoacetyl hydrazone rubomycin, 13-L-phenylalanyl hydrazone rubomycin, 13-BOC-3-(uracilyl-1)-DL-alanyl hydrazone rubomycin and 13-BOC-3-(adenylyl-9)-DL-alanyl hydrazone rubomycin. With successive treatment of rubomycin with hydrazine hydrate and respective ketones novel asymmetric azines were prepared: 13-cyclopentylidene hydrazone rubomycin, 13-alpha,alpha'-dimethyl-cyclopentylidene hydrazone rubomycin and 13-(1-phenylethylidene-1) hydrazone rubomycin. 14-Adenylyl-N9-rubomycin was synthesized by interaction of 14-bromorubomycin with adenine and hydrogenation of its analog, 14-N-imidazolyl rubomycin by sodium borhydrite yielded 13-dihydro-14-N-imidazolyl rubomycin. There was observed correlation between the antimicrobial activity of the derivatives against B. mycoides and their cytostatic effect on the cells of murine leukemia NK/LI. The high in vitro activity of 13-cyclopentylidene hydrazone rubomycin showed satisfactory correlation with the results of the study on the antitumor effect in animals.
A mutant strain of the bruneomycin-producing culture which produced up to 10% of the minor component was selected. The component was identified as streptonigrone. It was isolated and its physicochemical properties and antibacterial activity were investigated. Trimethylsilyl derivatives of streptonigrone and bruneomycin were prepared. Their PMR spectra and electron impulse mass spectra were studied. Streptonigrone was shown to have antibacterial and cytotoxic activities which was 1 to 2 orders of magnitude lower than that of bruneomycin.
Condensation of carminomycin or daunorubicin with glutaric dialdehyde in the presence of NaBH3CN yielded 3'-deamino-3'-piperidinocarminomycin or 3'-deamino-3'-piperidinodaunorubicin and corresponding (13-R, S)-dihydroderivatives. To prepare similar derivatives of 14-hydroxycarminomycin or doxorubicin, 13-dimethylketals of 14-bromocarminomycin or 13-bromodaunorubicin were used in the reaction of reductive alkylation with glutaric or glycolic dialdehyde to give 3'-deamino-3'-piperidino- or 3'-deamino-3'-morpholino derivatives of 13-dimethylketals of 14-bromocarminomycin or daunorubicin, respectively. After deblocking and subsequent hydrolysis of these compounds 3'-deamino-3'-piperidino- and 3'-deamino-3'-morpholino derivatives of 13-hydroxycarminomycin or doxorubicin were prepared. Reduction of the antibiotic derivatives under mass spectrometry conditions was demonstrated.
Explore the source record for details and available documents.
Condensation of daunorubicin or its (13 R, S)-dihydro derivative with inosine dialdehyde in the presence of NaBH3CN yielded novel derivatives of anthracycline antibiotics with incorporated inosine residue: 3'-deamino-3'-[(2" R)-(hypoxanthyl-9)-(6" S)-hydroxymethylmorpholino-N4"]- daunorubicin and (13 R,S)-dihydro-3'-deamino-3'-[(2" R)-(hypoxanthyl-9)-(6" S)- hydroxymethylmorpholino-N4"]-daunorubicin. The compounds did not inhibit growth of Bacillus mycoides and were less cytotoxic in vitro and less toxic in vivo than the parent antibiotics.
SIE AP mass spectra of tryptic peptides from the cyclo-GMP phosphodiesterase gamma-subunit and of chymotryptic peptides from the cyanogen bromide fragments of the same subunit exhibit MH+ ions for all theoretically possible smaller peptides. These facts show that SIE AP mass spectrometry can be successfully applied to peptide mapping using 1-2 nmoles of the compound.
For preparing new semisynthetic analogs of anthracycline antibiotics, hydrolysis of 13-dimethylketals of 14-bromrubomycin and 14-brom-arminomycin in solution of diluted hydrochloric acid was studied. It was shown that such hydrolysis yielded 14-chlorrubomycin and 14-chlorcarminomycin. Conditions for separating the mixture of 14-chlor- and 14-bromrubomycins and the mixture of 14-chlor- and 14-bromcarminomycins by HPLC were developed. Interaction of 14-chlorine derivatives of rubomycin and carminomycin with potassium formate in the presence of the crown ether yielded 14-formyloxy derivatives of rubomycin and carminomycin. Interaction of rubomycin and carminomycin with formic acid in the presence of N-oxysuccinimide and dicyclohexylcarbodiimide resulted in formation of N-formyl derivatives of rubomycin and carminomycin.
Antibiotic 308-I isolated from Actinomadura recticatena and the products of its degradation were studied with the methods of electron impact mass spectrometry, chemical ionization with ammonia, field desorption and ion extraction from solution under atmospheric pressure. It was shown that by its composition and structure antibiotic 308-I was identical to antibiotic BBM-928 A.
Mass spectrometry has been applied to the structural analysis of one of the glycopeptides from blastolysin, antitumor bacterial preparation isolated from the Lactobacillus bulgaricus cell wall. The glycopeptide (MW 10,000) was subjected to partial acid hydrolysis (6 N HCl, 100 degrees C) and the resulting products were dansylated or trifluoroacetylated and methylated or deuteromethylated. The mixture of these derivatives was examined by high-performance liquid chromatography or gas chromatography followed by mass spectrometry using electron impact and ammonia chemical ionization techniques.
Explore the source record for details and available documents.