Antagonistic activity of Malassezia Spp. towards other clinically significant yeast genera.

Antagonistic activity of Malassezia yeast towards clinically significant yeast species was studied. Ten Malassezia strains exhibited this activity. M. furfur strain exhibited maximum activity and the least sensitivity to "foreign" metabolites. M. globosa proved to be the most sensitive and the least active. M. furfur metabolites exhibited pronounced activity towards 6 Basidiomycetes strains. This effect was significantly higher in comparison with antagonistic activity towards 13 Ascomycetes species. Studies of a complex of M. furfur antagonistic metabolites showed that it has at least two components: thermolabile proteins with molecular weights of 33 and 35 kDa and a thermostable one, proteinase-resistant. In contrast to metabolites of many other yeast species, this substance is more effective against related Basidiomycetes microorganisms (Cryptococcus albicans), while antagonistic proteins are active mainly towards Ascomycetes, such as Candida albicans. It was found that mycocin-like activity of Malassezia is encoded by chromosomes, but not plasmids.

[The use of monoclonal antibodies with human IgE for determining the level of allergen-specific IgE]. / Ispol'zovanie monoklonal'nykh antitel k IgE cheloveka dlia opredeleniia urovnia allergenspetsificheskogo IgE.

The possibility of using monoclonal antibodies to human IgE, obtained in our laboratory, with the aim to determine allergen-specific IgE in the radioallergosorbent test (RAST), the enzyme immunoassay and the radioimmunoassay has been studied. The results obtained with the use of the standard RAST system (manufactured by Pharmacia, Sweden) and different variants of assay based on the use of our antibodies, labeled with 125I or conjugated with peroxidase, and timothy pollen allergen (obtained from the Stavropol Research Institute for Vaccines and Sera) have been compared. The best results have been obtained with anti-IgE antibodies 11-2, but for working out our assay systems it is necessary to develop our own standards and control limits.

[Monoclonal antibody-based immunoenzyme test system for determining the total immunoglobulin E level of children and adolescents]. / Immunofermentnaia test-sistema na osnove monoklonal'nykh antitel dlia opredeleniia obshchego urovnia immunoglobulina E u detei i podrostkov.

Enzyme immunoassay for determination of total immunoglobulin E in children and adolescents based on combination of two monoclonal antibodies with high affinity and specificity to different epitopes of IgE molecule has been developed. Monoclonal antibodies IgE/11-4 are used for sensitization of a solid phase (96-well plate), mcAB IgE/11-1 conjugated with horseradish peroxidase are used as a developing reagent. The following analytical characteristics of a test-system are established: range of assay--1-100 IU/ml sensitivity--1 IU/ml; time of analysis--1.5 hour, sample volume in duplicates--30 microliters. Immunoassay is simple, reliable and can be used in the field of pediatrics and allergology.

[Determination of phenathrene-9,10-epoxidase in the liver microsomes of rats. The effect of induction on the activity of the enzyme]. / Opredelenie aktivnosti fenatren-9,10-époksidazy v mikrosomakh pecheni krys. Vliianie induktsii na aktivnost' fermenta.

A new method for determination of the activity of phenanthrene-9,10-epoxidase, one of the monoxygenases of the system of drug metabolism, in rat liver microsomes was developed. The method includes the use of phenanthrene as substrate. The rate of the substrate epoxidation is measured with the help of HPLC reverse phase in accordance with the method of the internal standard (1-naphthol) by 9,10-dihydroxy-9,10-dihydrophenanthrene, a product of the intermediate epoxide hydrolysis. For rapid quantitative conversion of the formed 9,10-epoxy-9,10-dihydrophenanthrene endogenic epoxide hydrolase is used after selective termination of the monoxygenase reaction. The time of the assay by HPLC is 4.5 minutes. Phenobarbital is a more strong and selective inductor of this form of cytochrome P-450 than 3-methylcholanthrene. The simultaneous use of the two inductors does not result in additive increasing of the enzyme activity.

[Determination of the epoxide hydrolase activity in the peripheral blood lymphocytes of mammals]. / Opredelenie aktivnosti époksidgidrolazy v limfotsitakh perifericheskoi krovi mlekopitaiushchikh.

A highly sensitive method for determination of the activity of epoxide hydrolase (EH) (EC 3.3.2.3) in the mammalian lymphocytes was developed. 9,10-Epoxy-9,10-dihydrophenanthrene was used as substrate. For elimination of the enzyme latency the lymphocytes were solubilized with lubrol PX, a nonionic detergent. 9,10-Hydroxy-9,10-dihydrophenanthrene was estimated quantitatively by the method of the internal standard (1-naphthol) after reversed phase HPLC. The time of chromatographic matographic separation was 2.5 minutes. By the pH optimum EH in the lymphocytes differed from microsomal EH. However, the structure of their active sites was similar. Among the species studied (mice, rats, guinea-pigs, man), the lowest activity of EH was detected in the lymphocytes of mice and the highest activity in the lymphocytes of guinea-pigs. The activity of EH in the lymphocytes of man was 10-20 times higher than the sensitivity limit of the method (5 pkmol/mg/min). By its sensitivity and reproducibility and the level of the activity determined the method is much more superior to the methods described in the literature.

[Chromatographic method of determining membrane epoxide hydrolase activity]. / Khromatograficheskii metod opredeleniia aktivnosti membrannoi époksidgidrolazy.

A new method for determination of the activity of epoxide hydrolase (EC 3.3.2.3), an enzyme of the 2nd phase of the system of drug metabolism, in rat liver microsomes was developed. 9,10-Epoxy-9,10-dihydrophenanthrene was used as a substrate. The quantitative determination of 9,10-dioxy-9,10-dihydrophenanthrene was performed according to the method of the internal standard by HPLC in aqueous a cetonitrile on octylsilica gel with fluorescent detection. 1-Naphthol was used as the internal standard. The method is simple and requires no preliminary extraction of the sample and preparation of the derivatives. It is highly sensitive and rapid: the time of the chromatographic analysis is not more than 3 minutes. The error does not exceed 5 per cent.