Introduction. Compounds based on fused imidazole derivatives can become the basis for the development of a new generation of clinical therapeutic agents for more effective treatment of resistant human bacterial infections. This requires research, including the design, synthesis, and screening of biologically active compounds of this group.The aim. To study the effect of polyfunctional benzimidazole derivatives on the survival of Escherichia coli AB1157 culture and its ability to form biofilms.Methods. The antibacterial activity of the studied compounds was evaluated using the serial dilution method. Modeling of the formation of biofilms was carried out in the wells of an immunological plate with subsequent staining of the biomass with crystal violet.Results. The inhibitory activity of some of the studied compounds on the formation of biofilms by the Gram-negative bacterium E. coli AB1157 was demonstrated. The most pronounced inhibitory effect on E. coli AB1157 biofilms was exerted by 5-bromo-2-(trifluoromethyl)-1-H-benzimidazole. The level of biofilm formation decreased by 2–4 times in the area of concentrations of 15–60 µg/ml and by 8–10 times at concentrations of 125 µg/ml and above.Conclusion. The presented work expands the knowledge about the biological activity of benzimidazoles. The obtained results show that benzimidazole derivatives are good candidates for the development of new drugs against biofilms. The data obtained are of practical interest and need further study.

Аннотация. Рыбинское водохранилищеодин из крупнейших искусственных водоемов России, Шекснинский плес водохранилища подвергается наибольшему антропогенному воздействию в связи с поступлением в него сточных вод с предприятий Череповецкого комплекса. Тяжелые металлы, поступающие в водохранилище, могут накапливаться в организме, в том числе в хищникахпоследнем звене трофических цепей водоема. Цель работы: установить концентрацию тяжелых металлов в мышцах судака Sander lucioperca в Рыбинском водохранилище и определить ее соответствие российским и международным стандартам. Рыб отлавливали в нагульный период тралом в Шекснинском и Волжском плесах, измеряли, рассчитывали коэффициенты упитанности по Фультону и Кларк. В мышечной ткани определяли содержание Cd, Cr, Pb, Cu, Mn, Fe, Al, Co, Ni, V. Упитанность особей судака из Рыбинского водохранилища, вне зависимости от уровня локального антропогенного загрязнения, соответствовала средним значениям, характерным данному виду. В мышцах особей содержание никеля и ванадия было ниже предела обнаружения. В среднем в ткани содержалось в мг/кг влажного веса Cd 0,004, Cr 0,095, Pb 0,028, Cu 0,734, Mn 0,205, Fe 4,986, Al 12,538, Co 0,002. Концентрация Fe, Al, Mn в мышечной ткани судака из Шекснинского плеса достоверно превышала данные показатели Fe, Al, Mn у особей Волжского плеса. Потребление мяса судака из Рыбинского водохранилища не является потенциально опасным для здоровья человека, т. к. концентрации тяжелых металлов в мышечной ткани исследованных особей не превышают допустимые уровни элементов по российским и международным стандартам.

The bacteria Serratia proteamaculans 94 have a LuxI/LuxR type QS system consisting of AHL synthase SprI and the regulatory receptor SprR. We have previously shown that inactivation of the AHL synthase sprI gene resulted in an increase in the invasive activity of S. proteamaculans correlated with an increased bacterial adhesion. In the present work, the effects of inactivation of the S. proteamaculans receptor SprR are studied. Our results show that inactivation of the receptor sprR gene leads to an increase in bacterial invasion without any increase in their adhesion. On the other hand, inactivation of the sprR gene increases the activity of the extracellular protease serralysin. Inactivation of the QS system does not affect the activity of the pore-forming toxin ShlA and prevents the ShlA activation under conditions of a limited concentration of iron ions typical of the human body. While the wild type strain shows increased invasion in the iron-depleted medium, deletion of its QS system leads to a decrease in host cell invasion, which is nevertheless similar to the level of the wild type S. proteamaculans grown in the iron-rich medium. Thus, inactivation of either of the two component of the S. proteamaculans LuxI/LuxR-type QS system leads to an increase in the invasive activity of these bacteria through different mechanisms and prevents invasion under the iron-limited conditions.

Nowadays, the problem of inland water pollution is acute. It is caused by vast industrial growth and agricultural intensification. Concentrations of Cd, Pb, Zn, Cu, Mn, Fe, Mg, and Kwere determined in the muscles, liver, and gonads sabrefish from Rybinsk Reservoir areas with different anthropogenic loads. The tissue samples were analyzed by atomic absorption spectrometry. Heavy metals accumulated more intensively in the body of fish from more polluted areas of the reservoir. Among the analyzed elements, the maximum accumulation levels were found for K, Zn, and Fe and the minimum levels were observed for Cd and Pb. The gonads contained the largest concentration of Cd and Mn, the muscles contained the highest concentrations of Mg, and the other elements mainly accumulated in the liver of sabrefish. The THQ and HI values for all elements did not exceed 1, which suggests that there is no potential non-carcinogenic risk to human health. The target values of carcinogenic risk (TR) for cadmium ranged from 8.32 × 10⁻⁶ to 1.22 × 10⁻⁴ in the muscles. The increased content of cadmium in the gonads of sabrefish not only poses a risk to human health, but also to the reproduction of this species in the Rybinsk Reservoir.