Liquid Nutrient Medium Research Articles

The determination of specific phosphatmobilizing activity of soil microorganisms

The study aimed to compare the phosphate-mobilizing activity of 69 strains of the genus Bacillus on agar and liquid Muromtsev medium to identify a possible correlation between them. Research methods: microbiological, laboratory-analytical, and statistical. The main results of the study. The closeness of the relationships between the activity of phosphates dissolving on agar and liquid nutrient media by strains of the genus Bacillus have been determined. There is no significant correlation between the size of the dissolution zone on the agar medium and the phosphorus removal in the culture fluid in a liquid medium has been found. However, the correlation coefficients between specific indicators - specific phosphate-mobilizing activity in a liquid nutrient medium (the ratio of the total quantity of dissolved phosphorus to the amount of grown biomass) and specific phosphamobilizing activity on agar medium (the ratio of the zone dimensions of dissolution to the colony size) - is considerable: for the first group = 0.603; for the second group R = 0.752; for the third group R = 0.864; for the fifth group, R = 0.732. The correlation coefficient has an average value (0.415) for the fourth group, includes strains with high phosphate-mobilizing activity (museum strains B. subtilis 54, B. subtilis 72, B. subtilis 101s, B. subtilis 100), as well a new isolated from the soil strains of Bacillus sp. D-31 and D-32. There is a close correlation (R3 = 0,670) between two specific indicators: specific phosphate-mobilizing activity on agar medium (Kr) and specific activity of FMP dissolution in liquid medium (Asp.). (Analysis has conducted taking into account all investigated strains of bacilli). Conclusions. The new indicator of specific phosphate-mobilizing activity use will simplify the screening of strains on agar medium.

Conservation, Regeneration and Genetic Stability of Regenerants from Alginate-Encapsulated Shoot Explants of Gardenia jasminoides Ellis.

The present study demonstrates the potential of the alginate encapsulation of shoot tips and nodal segments of Gardenia jasminoides Ellis, the short-term cold storage of artificial seeds and subsequent successful conversion to desirable, uniform and genetically stable plantlets. Shoot tips and first-node segments below them, derived from shoots of in vitro cultures, responded better than second-to-fourth-node segments on agar-solidified Murashige and Skoog (MS) nutrient medium and thus, they were used as explants for alginate encapsulation. Explant encapsulation in 2.5% sodium alginate in combination with 50 mM of calcium chloride resulted in the production of soft beads, while hardening in 100 mM of calcium chloride formed firm beads of uniform globular shape, suitable for handling. The addition of liquid MS nutrient medium in the sodium alginate solution doubled the subsequent germination response of the beads. The maintenance of alginate beads under light favored their germination response compared to maintenance in darkness. Encapsulated shoot tip explants of gardenia, which were stored at 4 °C for 4, 8 or 12 weeks, showed a gradual decline in their regeneration response (73.3, 68.9, 53.3%, respectively), whereas, non-encapsulated explants (naked), stored under the same time durations of cold conditions, exhibited a sharp decline in regeneration response up to entirely zeroing (48.9, 11.1, 0.0%, respectively). Shoots, derived from 12-week cold-stored encapsulated explants, were easily rooted in solid MS nutrient medium with the addition of 0.5 μM of Indole-3-acetic acid (IAA) and after transplantation of the rooted plantlets individually to pots containing a peat–perlite (3:1, v/v) substrate, they were successfully acclimatized in the greenhouse under the gradual reduction of 75 or 50% shading with survival rates of 95–100%. The genetic stability of the acclimatized plantlets was assessed and compared with the mother plant using inter simple sequence repeat (ISSR) markers. ISSR analysis confirmed that all regenerated plantlets were genetically identical to the mother plant. This procedure of artificial seed production could be useful for the short-term storage of germplasm and the production of genetically identical and stable plants as an alternative method of micropropagation in Gardenia jasminoides.

Determination of drug resistance of Mycobacterium tuberculosis in the operating material

Currently, with the improvement of epidemic indicators for tuberculosis, the number of patients with drug-resistant forms of tuberculosis is increasing, which complicates and prolongs the treatment of such patients. The aim of the work is to study the drug resistance of Mycobacterium tuberculosis obtained from surgical material. Materials and methods: the study included 74 patients with medical and diagnostic operations on the chest organs. All patients were examined by standard methods: sputum and BAL microscopy with bronchoscopy (during the procedure), molecular genetic methods, culture on dense and liquid nutrient media. The diagnosis of tuberculosis was confirmed morphologically in all patients by histological examination of surgical material. When analyzing the results of drug resistance, it was found that among the newly identified patients, more than half (59.3%) had multiple (44.6%) p<0.005 and extensively drug resistance (14.7%) p= 0.003. At the same time, 74.5% (n= 35/47) of patients had no MBT in sputum before surgery. The frequency of development of drug resistance to first-and reserve-line antibacterial drugs, the structure of drug resistance depending on the group of dispensary registration is presented. A comparative analysis of drug sensitivity testing of MBT isolated from sputum before surgery and from surgical material was performed. The results of the study showed a high percentage of MBT drug resistance obtained in the operating material in patients with negative MBT tests. More than half of the patients who did not receive antibacterial therapy before surgery have multi drug resistance and extensively drug resistance, which suggests a high regional primary drug resistance of Mycobacterium tuberculosis.

Assessment of steel corrosion caused by pre-existing microorganism in produced water from an oil and gas facilities and its inhibition using glutaraldehyde

Microbiologically induced corrosion (MIC) is defined as corrosion caused by the activity of microorganisms which contribute to the high annual cost in oil and gas industries. Abundant microbial flora can be found in oil field formation waters which makes MIC inevitable. This brief preliminary study involves the growth of the microbes obtained from produced water sample from an oil and gas facility. Their corrosion activities on AISI 1018 carbon steel were also studied, including the utilization of glutaraldehyde as a corrosion inhibitor. The microbial growth was conducted on solid agar and liquid nutrient medium. The bio screening procedures were done by measuring the optical density using spectrophotometer and measurement of microbe dry weight. Laboratory scale corrosion test was conducted using weight loss method in simulated field condition. Glutaraldehyde was added in varying concentrations from 50 to 200 ppm to determine its effective dosage. The growth of colourless bacteria was observed in the agar medium, validated by the increased optical density in the liquid broth. The colourless bacteria were suspected as sulphur oxidizing bacteria (SOB) which is the main type of microbe that occurs in water. SOB induces corrosion in metal pipelines due to its oxidation reaction of sulphur compounds. The corrosion rate measured was 0.59 mm/year. The addition of 200 ppm of glutaraldehyde recorded the lowest corrosion rate which was 0.24 mm/year. It can be concluded that water sample from oil and gas field contained bacteria that causes MIC and can be controlled using glutaraldehyde, which has strong antibacterial and antifungal properties.

Screening of Enzyme Producers with Keratinase Activity among Marine Actinobacteria

About 2 million tons of feathers are produced annually around the world as a by-product of poultry farming. Due to the lack of funds and the complexity of processing, they have become one of the main environmental pollutants. The biodegradation of feathers by keratinolytic microorganisms has proven to be an effective, environmentally friendly and cost-effective method of bioconverting feather waste into a nutritious, balanced and easily digestible product that contains free amino acids, peptides and ammonium ions. Aim. To investigate the ability of marine actinobacteria to synthesize enzymes with keratinolytic activity and to study some of the physicochemical properties of the most active enzyme preparation. The object of the study was 10 strains of actinobacteria isolated from bottom sediments in the area of the Pradneprovsky trench of the Black Sea shelf. Methods. Caseinolytic (general proteolytic) activity was determined by the Anson method modified by Petrova, based on the quantitative determination of tyrosine, which is formed during the enzymatic hydrolysis of casein. Keratinase activity was determined by UV absorption at 280 nm of the hydrolysis products of keratin-containing raw materials. The cultivation of actinobacteria was carried out in a liquid nutrient medium with the addition of defatted chicken feathers as the main source of carbon and nitrogen. Results. The ability to hydrolyze keratin was found in five cultures. Moreover, all the strains studied were practically unable to break down casein. The Acty 9 strain (12 U/ml) showed the highest keratinase activity. Additional introduction of NaCl to the nutrient medium did not have a positive effect on the enzymes synthesis. The study of the physicochemical properties of the enzyme preparation Acty 9 showed that the pH and thermooptimum were 9.0 and 60°C, respectively. It retained 100% of the initial activity in the range of pH 7.0–10.0 after 3 h and 95% activity at pH 8.0 after 24 h of incubation. The studied enzyme preparation was thermostable, since it remained active for 3 h at 50°C and 1 h at 60°C. Conclusions. The extracellular keratinase synthesized by actinobacterium Acty 9 is promising for further research, since the enzyme is pH and thermostable and is not inferior in its physicochemical properties to those previously described in the literature.

Biosynthesis of Polyene Antibiotics and Phytohormones by Streptomyces netropsis IMV Ac-5025 under the Action of Exogenous Isopentenyladenosine

Streptomyces are active producers of a wide range of metabolites with multidirectional biological activity. Streptomyces netropsis IMV Ac-5025 synthesizes a polyene antibiotic complex in which two fractions were identified: heptaene candidine and a new tetraene fraction of unknown structure. The influence of secondary metabolites on the polyene antibiotics biosynthesis by soil streptomycetes is insufficiently explored. The aim of this work was to research the effect of exogenous isopentenyladenosine on the biosynthesis of polyene antibiotics and cytokinins by S. netropsis IMV Ac-5025. Methods. The strain was cultured in submerged cultivation condition in organic (soy) and synthetic (starch-ammonia) liquid nutrient media. The studies of biomass accumulation (gravimetric method), glucose consumption (glucose oxidase method), pH changes of culture media (ionometric method), biosynthesis of polyene antibiotics, and phytohormones (quantitative and qualitative thin layer chromatography spectrodensitometric method) were conducted. The results were analyzed in Statisticav.6.0 program. Results. It was found that polyene antibiotics are synthesized after the first day of cultivation, which indicates their role in the metabolism of streptomycetes. The biggest amount of the polyene antibiotics was accumulated in the stationary phase of producer growth (on the 7th day). It was found the decrease of polyene antibiotics and cytokinins accumulation in the producer’s biomass with the increase of exogenous cytokinin concentration from 25 ng/mL to 500 ng/mL. The bioproduction of the tetraene fraction was suppressed to a greater extent – up to 92% in the synthetic and up to 23% – in organic nutrient media. However, the amount of producer biomass increased under the action of the exogenous substance that confirming the positive effect of exogenous cytokinin on cell division of S. netropsis IMV Ac-5025. Exogenous isopentenyladenosine reduced the accumulation of endogenous cytokinins in streptomycetes biomass. Conclusions. The obtained results indicate an indirect metabolic relationship between the biosynthesis of polyene antibiotics and cytokinins in soil streptomycetes and provide a basis for the regulation of the biotechnological process for bioproduct formation with the appropriate quantitative composition of its components.

Drug sensitivity of low growing non-­­tuberculous mycobactria

Objective — analysis of drug resistance (DR) of some types of low growing non-­tuberculous mycobactria (NTMB) by the method of double serial microdilutions of drugs of different groups to determine the minimum inhibitory concentra­tions (MIC) in a liquid culture medium using the TREK Diagnostic Systems test system, Thermo Scientific SLOWMYCO for low growing mycobacteria.
 Materials and methods. Investigated 122 strains of low growing NTMB (M. avium, M. intracellulare, M. gordonae, M. kansasii, M. xenopi, M. malmoense and M. simiae), which were isolated in a liquid nutrient medium during sputum inoculation. DR was determined by the culture method using the TREK Diagnos­tic Systems kits (panel for low growing NTMB, which allows to determine the MIC of 13 drugs). The results were interpreted using an automatic bacteriological analyzer Sensititre Vizion System TREK Diagnostic Systems (USA).
 Results and discussion. Was found that for most M. avium strains the MIC of amikacin was 16.0—32.0 µg/ml, for ciprofloxacin — 16.0 µg/ml and higher, clarithromycin — 2.0—4.0 µg/ml, doxycycline — 16.0 µg/ml and above, ethambutol — 8.0—16.0 µg/ml. The MIC spectrum of ethionamide was distributed in the range from 1.2 to more than 20.0 µg/ml. MIC of isoniazid for most strains of M. avium was more than 8.0 µg/ml, linezolid — 16.0—32.0 µg/ml, moxifloxacin — 2.0—4.0 µg/ml, rifabutin — 0.25 µg/ml, rifampicin 4.0 µg/ml and above, streptomycin 64 µg/ml and above, and trimethoprim/sulfamethoxazole — more than 8.0/152 µg/ml. For M. intracellulare strains, in general, a similar situation with the M. avium strains with the MIC spectrum was observed. The work also provides MICs for the strains M. gordonae, M. kansasii, M. xenopi, M. simiae and M. malmoense. Based on the determination of the DR, the MIC50 and MIC90 values of each preparation of the SLOWMYCO panel were calculated for the studied species of low growing NTMB. Comparison of the MIC50 and MIC90 values with the limiting drug concentrations made it possible to determine the drugs effective against the studied types of NTMs.
 Conclusions. Determination of DR by the micromethod of serial dilutions in a liquid nutrient medium showed that most of the studied strains of low growing NTMPs are sensitive to clarithromycin and rifabutin. Amikacin, linezolid, and moxifloxacin were also quite effective. At the same time, drugs such as ethambutol, isoniazid, streptomycin, trimethoprim/sulfamethoxazole, suppressed the growth of the studied strains mainly in high concentrations, significantly exceeding the critical one.Until now, there is no single criterion for determining the DR NTM, and for the method used in this work, recommended by the Institute for Clinical and Laboratory Standards (USA), there are limitations in the interpretation of the results due to the untreated limit concentrations of drugs for various types of NTM. This is especially true for MAC, which play a major role in the development of mycobacteriosis. It was shown that the resistance profile of M. avium strains included the largest number of SLOWMYCO panel preparations compared to other types of NTMB, which dictates the need for studies aimed at comparing the results of in vitro DST with the effectiveness of therapy.

The quality assurance of the medicinal composition using the “Antimicrobial activity” indicator

The aim of the work is to determine the spectrum and strenght of antimicrobial activity of the studied compositions, to compare them with the activity of substancesand to select the most optimal concentration for further combination with each other. Topicality. Nowadays, one of the most common skin diseases is acne and demodicosis, the manifestations of which can be mild (comedones in seborrheic areas), more noticeable (papules-pustular rash) and severe (large cyanotic infiltrative elements in the back, prone to abscessing and scarring). The prevalence of acne and demodicosis currently reaches 90%. With these skin pathologies, it is desirable to use safe and effective drugs for external therapy, which provide rapid improvement of the skin (reduction of inflammation without side effects) to obtain a rapid and high-quality therapeutic effect. In the course of our research, we selected 3 active pharmaceutical ingredients (APIs): metronidazole, benzyl benzoate and benzoyl peroxide - according to the purpose of ICD-10 and their effectiveness in these pathologies. Mild medicines have an advantage over dermatological diseases such as acne and demodicosis because the use of soft medicines is local, namely a targeted effect on the microbial microflora. At present for production of soft medicines for local application such substances as macromolecular compounds are widely used, plasticizers, surfactants,etc. When creating a drug composition, a study was conducted aimed at obtaining soft medicines with certain consumer properties, in particular physicochemical (pH, osmotic activity, homogeneity,etc.) , physical and mechanical properties (rheological parameters). Materials for the study – soft medicines based on cetyl alcohol, Emulgade Sucro Plus, Polyvinylpyrrolidone, Carboxymethylcellulose, Tween 80, Triethanolamine, Propylene glycol, vaseline oil, which as (API) contains metronidazole, benzoyl peroxide, benzylbenzene. The specific antimicrobial activity of the samples was tested in accordance with Order № 167 of the Ministry of Health of Ukraine dated 05.04.2007 by the standard macromethod of serial dilutions in liquid nutrient medium and by the method of diffusion into agar. The minimum inhibitory concentration (MIC) of API (substrates) was determined. Results. The studied compositions of soft medicines and substrates revealed to presence of antibacterial (bacteriostatic) action against the test strains of microorganisms. Conclusions. The test of the compositions of soft medicines and the substance revealed the presence of a slight antibacterial (bacteriostatic) effect against the test strains of microorganisms. Key words: antimicrobial activity; active pharmaceutical ingredients (API); excipients; soft dosage form

ИНДУЦИРОВАНИЕ МИКРОКЛУБНЕОБРАЗОВАНИЯ НОВЫХ ПЕРСПЕКТИВНЫХ СОРТОВ КАРТОФЕЛЯ В АСЕПТИЧЕСКОЙ КУЛЬТУРЕ

The studies were carried out with the aim of optimizing microtubing of promising potato varieties in aseptic culture. The experiments studied such factors as the use of vessels of various sizes (test tubes with a diameter of 25 mm and plastic containers 18x18 cm, into which 10 ml of agar and 400 ml of liquid nutrient medium, respectively, were poured, respectively), the density of planting plants in containers (40, 60 and 80 stem explants), the composition of the nutrient medium during ontogenesis, cultivation of mini-tubers from in vitro microplants (control) and microtubers (≥ 0.9 cm and 0.5 ... 0.9 cm in size). When studying the possibility of modifying the nutrient medium based on the Murashige-Skoog recipe to induce tuberization in one variant, the sucrose concentration during growth was changed from 2% before the formation of four internodes by 8% after this phase, the kinetin content during the entire observation period was 0.5 mg/l. In the second variant, microplants were kept on a medium with 6% sucrose and 0.25 mg/l kinetin throughout ontogenesis. The highest yield of microtubers of the standard fraction (27 ... 94%) with a multiplication factor of 0.8 ... 2.7 pcs/plant was noted in the variant with 60 cuttings placed in a container. When grown in test tubes with a change of medium, 1.0 ... 1.5 microtubers were collected per plant with a standard fraction yield of 64 ... 78%. The use of container technology with a similar alternation of nutrient media increased the yield of the standard fraction in most of the studied varieties to 75 ... 86%. In variants with a constant sucrose content in the nutrient medium (6%), a very low multiplication factor was noted, which did not compensate for a sufficiently high yield of the standard fraction, regardless of the laboratory vessel used. The multiplication factor of test tube microplants during planting in the ground was higher than when planting microtubers, with a high yield of the standard fraction

Method of electrochemical biotesting for comparative analysis of probiotic and antibiotic properties of various plant extracts

Objectives. The purpose of this study was to develop an objective instrumental method for assessing microbial contamination and expressing the probiotic and antibiotic properties of food, pharmacological, and other products.Methods. The developed method consists of periodic (every 2 h) registration of changes in pH, redox potential, and electrical conductivity of a liquid nutrient medium incubated in the presence and absence of viable test microorganisms and test samples.Results. Using liquefied CO2 from 10 different types of plant materials, we carried out a comparative analysis of probiotic and antibiotic activities against Lactobacillus acidophilus of various concentrations of subcritical whole extracts obtained.Conclusions. Among the studied plant extracts, the most active prolonged antibiotic properties were exhibited by extracts from the leaves of Eucalyptus globulus Labill. and seeds of Illicium verum Hook.f. at a concentration in the test medium (CTE) more than 3 vol %, whereas the most active prolonged probiotic properties were exhibited by an extract from the herb of Mentha arvensis L. at CTE = 0.2 vol %. In most cases, the initial antibiotic activity of the tested extracts (TEs) was greater than their prolonged activity. Also, the mid-term (in terms of TEs interaction time with test microorganisms) antibiotic activity of TEs was intermediate in value between their initial and prolonged activity. In the test medium, the decreasing concentration of TEs decreases their antibiotic activity monotonically and increases their probiotic activity, suggesting that the biological activity of products, including various plant extracts, is largely determined not only by the raw material and the method of extracting biologically active substances from it but also by the concentration of the extract in the product and by the interaction time of the said product with microbiota and others. In most cases, a significant number of tests could establish the exact nature of these dependencies. The proposed method is much more rapid, objective, and informative and less laborious and material-intensive than using standard microbiological methods in assessing the initial microbial contamination and the probiotic and antibiotic properties of various samples of both the new and already approved pharmaceuticals, foods, and other products, as well as the individual ingredients and additives.

Use of an electrochemical biotesting technique for comparing the antibiotic properties of plant extracts obtained using liquefied CO<sub>2</sub>

We present a biotesting technique that allows periodic (every 2 hours) recording of changes in the pH, redox potential and electrical conductivity of a liquid nutrient medium incubated in the presence or absence of viable test microorganisms and test samples. This technique was used to compare the pro- and antibiotic activity of various concentrations of subcritical whole extracts obtained from 10 plant species using liquefied CO 2 against Lactobacillus acidophilus and other test microorganisms, such as Chlorella vulgaris and Rhodotorula glutinis. It was established that the proposed technique provides for a quicker, more objective and informative, as well as less material-consuming and labour-intensive, microbiological testing compared to conventional visual methods aimed at assessing effects of pharmaceutical, food and other products on the activity of test microorganisms. Among the studied plant varieties, extracts from celandine roots (Chelidonium majus) and calendula officinalis flowers (Calendula officinalis) at a concentration of 3% vol. and above demonstrated the most active prolonged antibiotic properties. Extracts from mistletoe shoots (Viscum album) and walnut leaves (Juglans regia) at a concentration of 0.2% vol. showed the most active prolonged probiotic properties. The initial pro- and antibiotic activity of the tested extracts was in most cases greater than their prolonged activity. At the same time, the medium-term (with respect to the period of interaction of the extracts and microorganisms) pro- and antibiotic activity of the tested extracts showed intermediate values between their initial and prolonged activity. It is noteworthy that a decrease in the concentration of the tested extracts in the test environment led to a steady decrease in their antibiotic activity, at the same time as increasing their probiotic activity. Thus, it is clear that the pro- and antibiotic activity of pharmaceutical, food and other products, including various plant extracts, is determined not only by the choice of raw materials and the method for extracting biologically active substances, but also by the concentration of extracts, the time of their interaction with microbiota and other living organisms, as well as by a variety of other factors. The exact nature of these dependencies can only be established through multiple tests, which can conveniently be carried out using the methodology presented in this work.

ИЗУЧЕНИЕ ПЕРСПЕКТИВНЫХ ШТАММОВ LACTOBACILLUSPLANTARUMДЛЯ ДАЛЬНЕЙШЕГО ИХ ИСПОЛЬЗОВАНИЯ В ЖИВОТНОВОДСТВЕ И ПТИЦЕВОДСТВЕ

This paper discusses the research findings on 6 strains of lactic-acid bacteria of the species Lactobacillus planta-rum. These cultures were isolated from plant substrates from the Altai Region and included in the “Siberian Collec-tion of Microorganisms”. The research was carried out in the Laboratory of Milk and Dairy Product Microbiology of the Department “Siberian Research Institute of Cheese Making” of the Federal Altai Scientific Center of Agro-Biotechnologies. The conventional methods of microbiolog-ical and biochemical studies were used. To conduct the experiments, 18-hour cultures of lactobacilli were used; their active acidity on a liquid nutrient medium, the number of bacterial cells in the resulting biomass and antagonistic activity against opportunistic pathogenic test cultures of Escherichia coli were studied. According to the research data, the active acidity of lactobacillus strains varied in the range of 3.43-3.70 pH, as compared with the control -6.98 pH. These values show an active growth of cultures Lb. plantarumon a nutrient medium; this is additionally confirmed by the high number of bacterial cells in all sam-ples of the studied microorganisms. All lactobacillus strains actively suppressed the growth of E. colitest cultures. The obtained results show that the studied Lb. plantarumstrains may be used as probiotic cultures in the future when creating bacterial preparations for farm animals and poultry.

АНТИБАКТЕРИАЛЬНАЯ АКТИВНОСТЬ 3-АРИЛИМИНОМЕТИЛХРОМОНОВ

In conditions of multiple drug resistance of microorganisms to recently used drugs, the search for new chemotherapeutic agents with a pronounced bactericidal or bacteriostatic effect with low toxicity and teratogenicity remains relevant. Chromone derivatives with a wide spectrum of pharmacological activity (membrane-stabilizing, antiviral, antibacterial, anti-inflammatory, cardioprotective, antioxidant) are promising compounds for the search for new generation chemotherapeutic drugs. As a result of the study, it was found that gram-positive bacteria Staphylococcus aureus shows the highest sensitivity to the studied compounds when growing on a liquid nutrient medium. The studied compounds are also active against pathogenic strains of Bacillus cereus, Escherichia coli. The minimum inhibitory concentration (IPC) of the most active substances in relation to St. strains aureus is 10 μg/ml for 7-acetoxy-3-(p-bromophenyl)iminomethylchromone, and for 3-(p-bromophenyl)-iminomethylchromone and 7-acetoxy-3-(p-sulfamidophenyl)iminomethylchromone – 20 μg/ml. For 7-acetoxy-3- (p-bromophenyl)iminomethylchromone and 3-(p-bromophenyl)iminomethylchromone, a high antibacterial activity was revealed with respect to the spore-forming bacteria Bacillus subtilis – MPC – 20 μg / ml. The synthesized compounds exhibit a low bacteriostatic activity with respect to the Pseudomonas aeruginosa strain. Experimental studies have shown that the nature and position of substituents in the structure of 3–aryliminomethylchromones affects their antibacterial activity against strains of gram-positive bacteria Staphulococcus aureus and Bacillus subtilis, a strain of gram-negative bacteria: Escherichia coli. The presence in the series of synthesized 3–aryliminomethylchromones of compounds with high bacteriostatic activity at the level of an antibacterial drug from the group of sulfonamides – norsulfazole was established.

Antibacterial effect of the antiseptic picloxydine dihydrochloride on conjunctival isolates of gram-negative bacteria

To study the effect of the antiseptic picloxydine dihydrochloride on the gram-negative bacteria Escherichia coli, Pseudomonas luteola and P. aeruginosa isolated from the conjunctiva. The identification of bacterial isolates and study of their sensitivity to antibiotics were carried out using the automated bacteriological analyzer BD Phoenix 100. To determine the bactericidal concentration, the method of serial dilutions of the antiseptic in a liquid nutrient medium was used. The binding of cationic molecules of picloxydine dihydrochloride to bacterial cells was detected by neutralizing the bacterial surface with increasing amounts of antiseptic, and measuring the zeta potential on the Zetasizer Nano ZS analyzer. The ultrastructure of bacterial cells was studied using the two-beam scanning ion-electron microscope Quanta 200 3D. The most resistant was P. aeruginosa. The interaction mechanism of picloxydine dihydrochloride with bacterial cells includes electrostatic binding of positively charged antiseptic molecules to negatively charged cell walls. Picloxydine dihydrochloride has a destructive effect on the bacterial cell wall and plasma membrane, which leads to cell lysis and release of intracellular components. Picloxydine dihydrochloride exhibits bactericidal activity against gram-negative conjunctival isolates and is promising for preventive use during repeated courses of intravitreal injections.

The use of plastic details to increase the contact surface of the substrate during the cultivation of attached species of algae

A series of experiments was carried out using strips (and nets) of synthetic polymers to increase the contact surface during the cultivation of attached forms of microphytes. We used bands of different composition, as well as with different microrelief surface areas, and a fine-mesh PLA network with an inhomogeneous surface. The experiments were performed on liquid nutrient media in accumulative cultures, and on solid nutrient medium in pure culture. The results showed a number of positive features of such cultivation, based on the selective isolation of individual species and their small combinations from the composition of accumulative cultures, as well as on the effective growth of individual species on specific elements of the microrelief of polymer surfaces. The polymers used were: PET, PP, LDPE, UHMWPE and PLA.

МЕТОДИКА ОПТИКО-ЭЛЕКТРОХИМИЧЕСКОГО МИКРОБИОЛОГИЧЕСКОГО ТЕСТИРОВАНИЯ В ПРИМЕНЕНИИ К СРАВНИТЕЛЬНОМУ АНАЛИЗУ ПРЕБИОТИЧЕСКИХ И АНТИМИКРОБНЫХ СВОЙСТВ РАЗЛИЧНЫХ РАСТИТЕЛЬНЫХ ЭКСТРАКТОВ

A biotesting technique is described that provides for periodic (every 2 h) recording of changes in the in-tensity of elastic light scattering, pH and electrical conductivity of a liquid nutrient medium incubated in the presence and absence of viable test microorganisms and test samples. The results of a comparative analysis using this technique of antibiotic activity against Staphylococcus aureus of different concentra-tions of whole subcritical extracts obtained using liquefied CO2 from 10 different types of plant raw mate-rials are presented. Studies have shown that among the samples studied by us, the most active prolonged antimicrobial properties were exhibited by extracts from the roots of Chelidonium majus and flowers of Calendula officinalis at their concentration in the test medium (CTE) more than 3 vol.%. And the most ac-tive prolonged prebiotic properties were exhibited by extracts from shoots of Viscum album and leaves of Juglans regia at CTE = 0.2 vol.%. In this case, the biological activity of the tested samples with respect to test microorganisms in most cases monotonically decreased with an increase in the interaction time of the mentioned microorganisms and samples. However, the exact nature of these dependencies in most cases can be established only with the help of a significant number of tests. And the latter can be conveniently carried out using the methodology presented in this work, which allows a much more rapid, objective and informative, as well as much less laborious and material-intensive, than when using standard visual mi-crobiological methods, to assess the effect on the dynamics of the vital activity of microorganisms of vari-ous tested samples.

Drugresistance of Mycobacterium tuberculosis from surgical material taken from patients with pulmonary tuberculosis

At present, with the improvement of epidemic indicators for tuberculosis, the number of patients with drug-resis- tant forms of tuberculosis is increasing, which compli- cates and increases the duration of treatment of suchpatients. The aim of the work is to study drug resistance of mycobacterium tuberculosis (MBT) obtained from sur- gical material. Methods. 74 patients with radical and di- agnostic operations on the chest organs were included into the study. All patients were examined by standard me thods: microscopy, molecular genetic methods, cul- turing on so lid and liquid nutrient media of sputum, and, in case of bronchoscopy, BALF. The diagnosis of tuber- culosis was confirmed morphologically in all patients by histological examination of the surgical material. When analyzing the results of DR MBT, it was found that among the newly diagnosed patients, more than half (59.3%) had multiple (44.6%; p<0.001) and extensive drug resistance (14.7%; p=0.003), while in 74.5% (n=35/47) before the op- eration MBT were not detected in sputum. The frequency of development of drug resistance to anti-tuberculosis drugs of the first and reserve lines, and the structure of drug resis tance depending on the group of dispensary registration are presented. Comparative analysis of MBT LS isolated from sputum before operations and from the operating material was conducted. The results of the study showed a high percentage of MBT drug resistance obtained in the operating material in patients with nega- tive MBT tests. More than half of patients who did not receive antibiotic therapy before surgery have MDR and XDR, which suggests a high regional primary drug resist- ance of Mycobacterium tuberculosis.

Методика оптико-электрохимического микробиологического тестирования в применении к сравнительному анализу свойств эфирных масел

Introduction. The national economy is currently developing a system for monitoring the quality and safety of goods. Food products, ingredients, and additives possess various pro- and antibiotic properties. Therefore, available express methods of quantitative assessment of microbiological contamination are a relevant aspect of domestic food industry.
 Study objects and methods. The study featured ten essential oils of plant origin that can be used as functional additives to various food products.
 Results and its discussion. The research introduced a new biotesting technique for repetitive recording of changes in the intensity of elastic light dispersion. The technique made it possible to measure pH and electrical conductivity of a liquid nutrient medium incubated in the presence and absence of viable test microorganisms and test samples. The paper describes the results of this technique applied to a comparative analysis of antibiotic activity of various essential oils in different concentrations. As the concentrations of the test extracts decreased, their antibiotic activity monotonically also went down, while the probiotic activity increased. The shortterm biological activity of test samples appeared to be significantly higher than their long-term activity. The medium-term biological activity of the test samples was mostly intermediate in value. Only rarely did it exceed both the long- and short-term biological activity of the same TE. The essential oils obtained from the leaves of Thuja occidentalis, Eucalyptus globulus, and Cupressus sempervirens exhibited the most active and long antibiotic properties.
 Conclusion. The biological activity of food products, including various plant extracts, depends not only on the raw material and the extraction method, but also on the concentration of the extract in the product. As a rule, the exact nature of these dependencies can only be established empirically and requires a set of various tests. The present article introduces a new highly objective and informative express methodology that simplifies this process. The technique is less labor-, time-, and material-consuming than standard visual microbiological methods. It can be used to assess the effect of test samples on the vital activity of microorganisms in various foods, ingredients, and additives.

Биологические особенности и условия поверхностного культивирования штаммапродуцента микробиопрепарата 11-3 Bacillus sp. – антагониста возбудителей фузариоза льна масличного

To develop a technological regimen of production of microbiopreparation in a preparative form ‘wettable powder’ (WP) we studied biological features and conditions of surface cultivation of the strainproducer 11-3 Bacillus sp. – an antagonist of fusariosis pathogen infecting oil flax. Cultural qualities of the strain-producer were studied in three agarized mediums. The optimal conditions for cultivation of the strain-producer on liquid nutrient mediums are estimated: temperature – 30–35 оС, рН – 8–10. As a source of carbon nutrition, glycerin and molasses can be used. Yeastrel and corn-steep concentrate are the optimal sources of nitrogen nutrition; the Tylon’s medium is optimal compound liquid nutrient medium for cultivation of the perspective bacterial strain 11-3 Bacillus sp. Optimal period of the surface cultivation of the bacterial strain 11-3 Bacillus sp. on the liquid nutrient Tylon’s medium was ten days, and a volume of sowing culture to nutrient medium – 2.0%.

АМИНОКИСЛОТЫ И БЕЛКИ В КУЛЬТУРАЛЬНЫХ ФИЛЬТРАТАХ ГРИБА – ВОЗБУДИТЕЛЯ АНТРАКНОЗА COLLETOTRICHUM LINI

The research was carried out on the basis of laboratory biotechnologies of All-Russian research institute of flax (Tver region) in 2010–2012, 2016. The aim of the work was to determine the amino acid and protein composition of culture filtrates of the anthracnose pathogen fungus Colletotrichum lini Manns et Bolley in order to adjust the concentration of selective agent in the nutrient medium when creating in vitro new flax genotypes resistant to anthracnose. It was established that the culture filtrates of strains 527 and 608 contain such amino acids as alanine, glycine, asparagine, cysteine, threonine, aspartic acid, glutamic acid, as well as arginine in strain 527 and traces of tyrosine and lysine in strain 608. It was established that the concentration of amino acids in EC of strain 527 was significantly higher than in culture filtrate of strain 608. It was shown that the toxicity of the culture filtrate depended on the degree of aggressiveness of the anthracnose pathogen strain – culture filtrate of a strongly aggressive strain is more toxic than the culture filtrate of a weakly aggressive strain. Studies have revealed that when cultivating the fungus-causative agent of anthracnose on a nutrient medium, as the mycelium of fungus grew, the concentrations of asparagine, alanine, aspartic and glutamic acids, and glycine decreased in the culture filtrates. It was established that the change in amount of proteins happened during the entire period of cultivation of the mycelium of fungus on a liquid nutrient medium. It is shown that accumulation and content of proteins in culture filtrates of strains of different aggressiveness occurs in different ways. The more aggressive strain is (639), which is more toxic, contains and accumulates more proteins in the culture medium during the entire period of growth and development the less aggressive strain is (419).