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Документ Synergetic antimicrobial activity of a mixture of essential oils and Acinetobacter calcoaceticus IMV B-7241 surfactants synthesized in the presence of the eukaryotic inducer(2023) Pirog, Tatiana; Kliuchka, Igor; Kliuchka (Nykytyuk), LiliaThe research was devoted to study the synergetic antimicrobial effect and role in the destruction of biofilms under the action of a mixture of tea tree or cinnamon essential oil with surfactant Acinetobacter calcoaceticus IMV B-7241, synthesized in the presence of a yeast inducerДокумент Effect on phytopathogenic microorganisms of surfactants of microbial origin(2021) Pirog, Tatiana; Piatetska, Daria; Yarova, Hanna; Iutynska, GalynaBiodegradable non-toxic surfactants of microbial origin are multifunctional preparations, which due to antimicrobial activity are promising for use in crop production to control phytopathogenic microorganisms. Studies on the prospects of using microbial surfactants to control the number of phytopathogenic microorganisms are conducted in three directions: laboratory studies of antimicrobial activity of surfactants in vitro, determination of the effect of surfactants on phytopathogens in vegetative experiments in the process of plants growing in a laboratory or greenhouse, post-harvest treatment of fruits and vegetables with solutions of microbial surfactants to extend their shelf life. The review presents literature data on antimicrobial activity of surfactants against phytopathogenic bacteria and fungi in vitro. Antimicrobial activity of surfactants is evaluated by three main parameters: minimum inhibitory concentration, zones of growth retardation of test cultures on agar media and inhibition of growth of test cultures on agar or liquid media. The vast majority of available publications relate to the antifungal activity of surfactant lipopeptides and rhamnolipids, while data on the effect of these microbial surfactants on phytopathogenic bacteria (representatives of the genera Ralstonia, Xanthomonas, Pseudomonas, Agrobacterium, Pectobacterium) are few. The researchers determined the antimicrobial activity of either total lipopeptides extracted with organic solvents from the culture broth supernatant, or individual lipopeptides (iturin, surfactin, fengycin, etc.) isolated from a complex of surfactants, or culture broth supernatant. Lipopeptides synthesized by members of the genus Bacillus exhibit antimicrobial activity on phytopathogenic fungi of the genera Alternaria, Verticillium, Aspergillus, Aureobasidium, Botrytis, Rhizoctonia, Fusarium, Penicillium, Phytophora, Sclerotinia, Curvularia, Colletotrichum, etc. in sufficiently high concentrations. Thus, the minimum inhibitory concentrations of lipopeptides against phytopathogenic fungi are orders of magnitude higher (in average 0.04–8.0 mg/mL, or 40–8000 μg/mL) than against phytopathogenic bacteria (3–75 μg/mL). However, the antifungal activity of lipopeptidecontaining supernatants is not inferior by the efficiency to the activity of lipopeptides isolated from them, and therefore, to control the number of phytopathogenic fungi in crop production, the use of lipopeptidecontaining supernatants is more appropriate. Rhamnolipids synthesized by bacteria of the genus Pseudomonas are more effective antimicrobial agents comparing to lipopeptides: the minimum inhibitory concentrations of rhamnolipids against phytopathogenic fungi are 4–276 μg/mL, which is an order of magnitude lower than lipopeptides. In contrast to the data on the antifungal activity of rhamnolipids against phytopathogens, there are only a few reports in the literature on the effect of these surfactants on phytopathogenic bacteria, whilst the minimal inhibitory concentrations are quite high (up to 5000 μg/mL). The advantage of rhamnolipids as antimicrobial agents compared to lipopeptides is the high level of synthesis on cheap and available in large quantities industrial waste. Currently in the literature there is little information about the effect of surface-active sophorolipids of microbial origin on phytopathogenic fungi, and all these works are mainly about the antifungal activity of sophorolipids. We note that in contrast to surfactant lipopeptides and rhamnolipids, the effective concentration of most sophorolipids, which provides the highest antimicrobial activity against phytopathogens, is higher and reaches 10,000 μg/mL.Документ Synergism of antimicrobial and anti-adhesive activity of Nocardia vaccinii IMV B-7405 surfactants in a mixture with essential oils(2020) Pirog, Tatiana; Kliuchka (Nykytyuk), Lilia; Kliuchka, Igor; Shevchuk, Tetiana; Iutynska, GalynaAn increase in the antibiotic resistance of pathogenic microorganisms has stimulated the search for alternatives to antibiotics substances of natural origin, which are essential oils (EO) and non-toxic biodegradable microbial surfactants. Aim. To investigate the antimicrobial and anti-adhesive activity of a mixture of EO and surfactants of Nocardia vaccinii IMV B-7405 synthesized on various oil-containing media. Methods. N. vaccinii IMV B-7405 was grown in medium containing as carbon source refined sunflower oil, oil after frying french fried potatoes, potato wedges and meat. The surfactants were extracted from supernatant of cultural liquid by modified Folch mixture. The antimicrobial action of tea tree, cinnamon and lemongrass EO, surfactants and their mixtures was determined by index of the minimum inhibitory concentration (MIC). Synergistic effect of surfactants and EO was evaluated by indicator of fractional inhibitory concentration. The degree of bacteria and fungi biofilms destruction under the action of surfactants, EO and their mixtures was determined by spectrophotometric method. Results. It was found that N. vaccinii IMV B-7405 surfactants synthesized on all oil-containing substrates showed a synergistic antimicrobial and anti-adhesive activity with the investigated EO. MIC of a surfactants and EO mixture against bacteria (Bacillus subtilis BT-2 (spores), Escherichia coli IEM-1, Staphylococcus aureus BMS-1) and yeast (Candida albicans D-6, Candida utilis BVS-65 and Candida tropicalis RE-2) were 2–20 μg/ml and were significantly lower than each compound separately (156–625 and 8–80 μg/ml for EO and surfactants, respectively). The destruction of bacterial and yeast biofilms under the action of a mixture of surfactants (20–40 μg/ml) and EO (20–40 μg/ml) was 1.3–2.9 times higher compared with using of each component separately at similar concentrations. Conclusions. The data presented the possibility of using a mixture of EO and surfactants not only to reduce their MIC, but also as effective antimicrobial and anti-adhesive agents.Документ Effect of tryptophane on synthesis of certain exometabolites by bacteria of genus Acinetobacter, Nocardia, and Rhodococcus and their properties(2022) Pirog, Tatiana; Piatetska, Daria; Zhdanyuk, Valentina; Leonova, Natalia; Shevchuk, TetianaThe efficiency of integrated microbial biotechnologies for obtaining several practically valuable metabolites in one technological process is determined both by the maximum concentration of these substances and their properties. This is especially true for secondary metabolites, the composition and properties of which vary depending on the cultivation conditions of the producer. Aim. To research the eff ect of tryptophan (a precursor of auxin biosynthesis) in the culture media on the synthesis of certain exometabolites by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241, and Nocardia vaccinii IMV B-7405 as well as their properties. Methods. R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-724, and N. vaccinii IMV B-7405 were cultivated in a medium containing refi ned and waste sunflower oil, biodiesel waste, or ethanol as a carbon source. The concentration of tryptophan in the medium was 300 mg/L. Surfactants were extracted from the supernatant of the cultural liquid with a modified Folch mixture. Phytohormones were isolated from the supernatant by sequential extraction with organic solvents after surfactant extraction. Thin-layer chromatography was used for preliminary purification and concentration of phytohormones. Qualitative and quantitative determination of auxins was performed using high-performance liquid chromatography. The antimicrobial activity of surfactants was analysed by the minimum inhibitory concentration. The activity of enzymes of surface-active glycoand aminolipids biosynthesis (phosphoenolpyruvate synthetase, phosphoenolcarboxykinase, and NADP+-dependent glutamate dehydrogenase) was determined spectrophotometrically during the oxidation of NADH or NADP. Results. It was found that the presence of tryptophan in the culture medium of the strains under study did not affect the number of synthesized surfactants, which was 1.80−1.90, 1.55−1.75, and 1.50−1.65 g/L, respectively. At the same time, cultivation of R. erythropolis IMV Ac-5017, A. calcoaceticus IMV B-724, and N. vaccinii IMV B-7405 in the media with tryptophan increased the number of phytohormones: it was higher than the amount of phytohormones synthesized during cultivation without a precursor. The introduction of tryptophan into the culture medium of the strains was accompanied by the formation of surfactants. These compounds showed 2−4 times higher antimicrobial activity against the phytopathogenic bacteria (Agrobacterium tumefaciens UCM B-1000, Pseudomonas syringae UCM B-1027T, Xanthomonas vesicatoria UCM B-1106, Pectobacterium carotovorum UCM B-1075T, Clavibacter michiganensis IMV B-102 and Pseudomonas syringae pv. tomato IMV B-9167) than compounds synthesized on a medium without a precursor. The antimicrobial activity of surfactants synthesized by A. calcoaceticus IMV B-7241 in the presence of tryptophan either did not change compared to that for surfactants obtained without tryptophan, or increased slightly. Data on the activity of surfactant biosynthesis enzymes correlated with the indicators of their antimicrobial activity. In the presence of tryptophan in the culture medium of N. vaccinii IMV B-7405 and R. erythropolis IMV Ac-5017, NADP+-dependent glutamate dehydrogenase activity in the cells of these strains (a key enzyme for biosynthesis of aminolipids responsible for antimicrobial activity) increased almost by 1.4 times compared to that on a tryptophan-free medium. Conclusions. As a result of this work, it was found that the presence of tryptophan in the culture medium of researched strains did not affect the number of surfactants. The antimicrobial activity of surfactants against phytopathogenic bacteria either increased or remained unchanged compared to that established for surfactants synthesized without a precursor of auxin biosynthesis. The obtained data testify to the high efficiency of the potential use of surfactants complex preparations and phytohormones in crop production to stimulate the growth of plants and biocontrol of phytopathogenic bacteria.