Natural ecdysteroids isolated from Serratula coronata L., including 20-hydroxyecdysone (20-HE), 25-S-inokosterone, and ecdysone, did not exhibit antimicrobial activity with respect to most standard test microbe cultures. The introduction of the acetyl group into the 20-HE molecule significantly increased the antibacterial activity with respect to microbes inducing inflammatory and purulent processes. Acyl derivatives of 20-hydroxyecdysone can be suggested for use in wound-healing compositions 268 0091-150X/06/4005-0268

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Aim. The article deals with the results of research, the aim of which was to determine antifungal activity of the strains Bacillus and Streptomyces genera, in relation to phytopathogenic fungi, widely distributed in Moldova. Methods. Strains were grown on classical agar media, the antifungal activity was determined by the method of agar blocks with test cultures -phytopathogenic fungi. Biological standard was the bacterium B. subtilis 26D. In the experiments on the germination of A. alternata conidia, 5 bacterial cultures grown in liquid nutrient medium No. 2. Results. It is established that all bacteria of genus Bacillus exhibit antifungal activity against test cultures, but in varying degrees. The growth of B. cinerea and F. oxysporum was least inhibited. Strain B. subtilis S4 most actively suppressed the growth of S. sclerotiorum. Strain Streptomyces sp. 10 is able to completely suppress the growth of A . alternata and B. cinerea, and the strain S. sp 9 completely suppressed the growth of S. sclerotiorum. Strains 9, 12, and 66 actively inhibited growth of F. culmorum (the radius of the zones was 16.0−20.0 mm), and strain S. sp. 185 against F. oxysporum (zones up to 28.0 mm). The strongest inhibitory effect on the germination of A. alternata conidia had strain S2. Conclusions. A comparative assessment of the antifungal activity of B. subtilis revealed a strain with the most pronounced antifungal properties. The investigated liquid cultures of bacteria of the genus Bacillus exhibited a special fungicidal effect on the germination of A. alternata conidia. Among 7 strains of streptomycetes tested, particular interest had S. sp. 10, capable to completely suppressing the growth of A. alternata and B. cinerea, and the strain S. sp. 9 -completely inhibits the growth of S. sclerotiorum, as well as the strain S. sp. 185 actively inhibited the growth of F. oxysporum and the strain S. sp. 10 − A. solani.

The work is devoted to the study of the effect of a low-frequency magnetic field of low intensity on microorganisms. We proceeded from the fundamental fact that the Earth's magnetic field (natural electromagnetic background) is the most important environmental factor affecting all vital processes of living organisms. It is important to realize that in the modern world the negative anthropogenic impact on the natural electromagnetic background has significantly increased due to the rapidly growing number of sources of technogenic fields. The relevance of research is due to the great scientific and practical interest in the issues of survival and growth of colonies of microorganisms under the influence of a magnetic field. We set ourselves the goal of studying the action, in particular, of a low-frequency magnetic field of low intensity. Our task was to find out how the key characteristics of the culture of microorganisms (growth and survival) change under the influence of different field values. We used the device "Biostimulus 1", developed by us at IEINT, which makes it possible to influence biological material with a low-frequency magnetic field of low intensity at specified values. The microbiological material was investigated - Streptomyce canosus CNMN-Ac-02 in the form of an aqueous suspension; an aqueous suspension pounded on the surface of agar and in lyophilic form. Exposure time: 10, 15 and 20 minutes. As a result, it was found that when an aqueous suspension of Streptomyce canosus CNMN-Ac-02 was treated with a magnetic field for 10 and 15 minutes, the appearance of colonies of 2 types with mycelium of different color and size was observed. With an exposure of 20 min. colonies of 4 types arise with the peculiarity of some colonies to release a pigment of a new color into the medium. In the case of a culture in the form of a suspension pounded on agar, similar results were obtained. The survival rate of the S.canosus CNMN-Ac-02 streptomycete strain after exposure to a magnetic field depends on the treatment time, as well as on the state of the culture (dry lyophilized culture or its aqueous suspension).

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