Ivan Sergeevich Sazykin

журнал Живые и биокосные системы Экотоксикологические показатели воды рек Дон и Темерник в акватории городов Ростов-на-Дону и Азов

Environmental pollution with oil and petroleum products is currently one of the most pressing and acute global environmental problems. Traditional methods eliminating such pollution are often ineffective or expensive, leading to the search for alternative environmentally friendly solutions. Therefore, bioremediation technologies using degradative microorganisms are of particular interest. Currently, many halophilic microorganisms are considered promising oil oxidizers due to their high resistance to stress conditions. In this study, the utilization degree of six different hydrocarbons by 12 microbial consortia isolated from surface sediments of salt lakes in five regions of Russia was assessed. Degradation activity was assessed using the redox indicator 2,6-dichlorophenolindophenol (DCPIP). Results showed that all the studied consortia exhibited degradation activity. Using the nonparametric Friedman test, significant differences in their effectiveness were identified, allowing them to be divided into three groups: high, medium, and low effectiveness. The Lake Sukko and Lake Elton consortia were considered highly effective, suggesting they have potential for bioremediation.

журнал Живые и биокосные системы Оценка резистома условно-патогенных бактерий, выделенных из воды рек Дон и Темерник в акватории городов Ростов-на-Дону и Азов

This article is devoted to the synthesis and investigation of a family of new benzimidazole compounds with a propylsulfonate moiety, synthesized by condensation of salicylic aldehyde or its 5-substituted derivatives with 3-(2,3-dimethylbenzimidazol-1-ium-1-yl)propane-1-sulfonate. The structure of the obtained dyes was confirmed using NMR, FT-IR, and HRMS. Absorption and photoluminescence properties were studied in phosphate buffers over a wide pH range, and changes in the absorption and fluorescence spectra of DMSO solutions upon titration with DIPEA and HCl were also studied. It was found that all the target compounds possess pH-sensitive optical properties and can be used as fluorescent probes, while methoxycarbonyl-substituted derivative 3c demonstrated the most prominent optical and fluorescent response starting from pH ~ 4.5. The toxicity of the compounds was studied using whole-cell bioluminescent bacterial sensors. The effect on the biomass and metabolic activity of strains Staphylococcus aureus ATCC 6538-P FDA 209-P and Escherichia CDC F-50 bacterial biofilms was also investigated. In the final stage of the study, bioimaging experiments were carried out using the selected most promising dye 3c and biofilms. It was demonstrated that the dye can be excited by light with wavelengths of 458 nm or 750 nm in multiphoton mode. Importantly, when biofilms are incubated in the dye solution for 3 h, only the extracellular matrix is stained. However, if the staining time is increased to 24 h, dye penetration into bacterial cells is observed, resulting in a second photoluminescence maximum during sample analysis. It is important to note that when biofilms are incubated in a dye solution for 3 h, only the extracellular matrix is stained, while with longer staining, penetration of the dye into bacterial cells is observed, and a second photoluminescence maximum appears during sample analysis. The results obtained demonstrate a high potential of using benzimidazole-based compounds as pH-sensitive fluorescent probes operating in a biologically relevant pH range, which can be used for imaging of bacterial biofilms.

Pseudomonas aeruginosa (Schroeter) Migula) and Klebsiella (Klebsiella pneumoniae subsp. pneumoniae (Schroeter) Ørskov) are opportunistic bacteria with etiological significance in multidrug-resistant infections occurrence. The presence of these bacteria strains in water bodies may indicate anthropogenic fecal contamination. Strains in wastewater and surface waters may represent an antibiotic-resistant bacteria reservoir. The aim of the study was to assess the antibiotic sensitivity of Klebsiella pneumoniae and Pseudomonas aeruginosa strains isolated from the Don and Temernik rivers in the Rostov-on Don and Azov water areas, as well as wastewater from sewage treatment plants in Aksai and Novoshakhtinsk. To recover and enrich the microorganisms, the water samples were inoculated onto both liquid and solid media in accordance with established methodological guidelines, using a serial dilution technique. Bacterial isolates were identified via biochemical tests and mass spectrometric analysis (Microflex LT MALDI-TOF MS). Antibiotic susceptibility testing was performed using the disk diffusion method according to EUCAST clinical recommendations. In total we identified 22 strains of Klebsiella pneumoniae and 76 strains of Pseudomonas aeruginosa. The Klebsiella isolates demonstrated absolute susceptibility to ciprofloxacin, aminoglycosides, chloramphenicol, and meropenem; however, certain resistant phenotypes were observed against amoxicillin-clavulanate, nitrofurantoin, and cefepime. Pseudomonas aeruginosa strains exhibited complete susceptibility to fluoroquinolones and aminoglycosides, though up to 25% of the isolates were resistant to imipenem and meropenem. Furthermore, several multidrug-resistant strains were detected, displaying simultaneous resistance to multiple β-lactam antibiotics (cefepime, imipenem, and meropenem). The findings of this study confirm that both surface water bodies and wastewater can serve as reservoirs for the dissemination of multidrug-resistant bacteria.

журнал Живые и биокосные системы Токсичность никотинсодержащих жидкостей для электронных систем доставки никотина

журнал Живые и биокосные системы Оценка воздействия лекарственных растений на образование бактериальных биопленок

Spiropyran salts containing a cationic vinyl‐3H‐indolium moiety are characterized by NIR absorption and fluorescence of their merocyanine forms. This feature makes them promising fluorescent probes and markers for bioimaging. The article focuses on the synthesis and study of the spectral, kinetic and toxic characteristics of such compounds with respect to various substituents in different moieties and the type of anion. A detailed analysis of the acquired data made it possible to draw some important conclusions regarding the influence of structural factors, which will be very useful for the further rational design of such derivatives. In particular, it was shown that the counterion has minimal effect on the spectral and kinetic characteristics of the dyes but dramatically affects the toxicity of the compounds. Following selection of the most appropriate compounds, bioimaging experiments were carried out to visualize planktonic bacteria and bacterial biofilms of E. coli and A. calcoaceticus. The ability to visualize biofilms is critical for the diagnosis of chronic diseases. By the results of molecular docking a theoretical interaction pattern between spiropyran molecules and DNA was proposed.

Soils are a hotspot for the emergence and spread of antibiotic resistance. The effects of agrochemical treatments on the bacterial community of agricultural soils and the content of antibiotic-resistance genes (ARGs) were studied. Treatments included the following: control, mineral fertilizers (NPKs), pesticides, and the combined treatment of soils under soya (Glycine max), sunflower (Helianthus annuus L.), and wheat (Triticum aestivum). Bacterial community taxonomic composition was studied using 16S rRNA gene sequencing. The content of 10 ARGs and 3 integron genes (intI1, intI2, intI3) was determined using quantitative real-time PCR. The results showed that the treatments had little effect on the taxonomic composition and diversity of the soil bacterial community. The most significant factors determining differences in the microbial community were sampling time and soil physico-chemical parameters. A significant role of the bacterial community in ARG distribution in soils was demonstrated. Representatives of the Pseudomonas, Bacillus, Sphingomonas, Arthrobacter genera, and the Nocardioidaceae and Micrococcaceae families were likely ARG hosts. The presence of integron genes of all three classes was detected, the most numerous being intI3. This work provides important information on the role of agricultural soils in ARG transfer, and the findings may be useful for sustainable and safe agricultural development.