SURVIVAL OF BURKHOLDERIA PSEUDOMALLEI IN CELLS OF TETRAHYMENA PYRIFORMIS CILIATE INFUZORIAN: EFFECT ON TETRAHYMENA ENCYSTMENT ACTIVITY

Objective of the study was to model the interaction of Burkholderia pseudomallei with Tetrahymena pyriformis in vitro and investigate the changes in the population composition of the protozoa when co-cultured with a microorganism.Materials and methods. B. pseudomallei 110, C141, 57576, 107 strains differing in virulence for BALB/c mice were used. The axenic culture of T. pyriformis was incubated with microorganisms in 100 to 1 ratio, at 28 °C, in LB. Samples of co-cultures were examined using light microscopy, by counting the number of trophozoites and cysts in the population. Dynamics of multiplication of B. pseudomallei cultures associated with T. pyriformis was determined through seeding bacteria on a dense nutrient medium to count the grown colonies.Results and conclusions. B. pseudomallei in association with T. pyriformis is ingested by protozoan cells; it multiplies in them and stimulates protozoa encystment. Hereby virulent strain B. pseudomallei 110 induces encystment of T. pyriformis on days 2–4 and complete cell destruction within 7–8 days. Avirulent strain, B. pseudomallei 107, induces full encystment on day 7; significant part of the cysts remains intact on day10. Dynamics of B. pseudomallei growth, co-cultured with T. pyriformis is characterized on day 1 by distinct decrease in the number of viable bacterial cells and increase in it within following 24 hours. Bacteria concentration curves depend on the virulence of the strain: maximum level of B. pseudomallei 110 replication is observed after 48 hours, while that of B. pseudomallei 107 – not less than after 7–8 days

Burkholderia pseudomallei Morphotypes that Form in vitro under Stress Conditions

Objective of the study was to determine diversity of the morphotypes formed in vitro from the initial morphological variant of B. pseudomallei 110 under stressful conditions and to study some phenotypic characteristics of them. Materials and methods. Virulent strain Burkholderia pseudomallei 110 of Australian serotype was used. Burkholderia cultures were added to the axenic culture of Tetrahymena pyriformis in LB broth and sterile river water in the ratio of 100: 1 and incubated at 28 °C; the passage of monocultures and cultures in protozoa cells was repeated at intervals of 3–4 days. Morphotypes were identified on Ashdown’s medium after cultivation for 3–4 days at 32 °C, photographs were analyzed based on classification of Chantratita et al. In all morphotypes the activity of extracellular enzymes and virulence were determined on the model of golden hamsters. Results and conclusions. Seven B. pseudomallei 110 colony morphotypes were identified. Four of them with characteristics of I, III, IV and VII morphotypes, described by Chantratita et al., were named Chl (Chantratita like variant). The study of morphotypes in different samples revealed a variation in them, depending on the culture medium (LB broth or water), and their different ratios in individual samples. The greatest number of morphological variants (4 out of 7) was formed during the passage of the monocultures of B. pseudomallei 110 in LB broth; in water the initial culture was almost entirely (95 %) transformed into morphotype I Chl. Under other conditions of cultivation the dominant V morphotype was formed, and in the presence of protozoa it was combined predominantly with I Chl. Morphotypes differed in the production of extracellular enzymes, motility and reduced virulence

BIOLOGICAL SAFETY: ANALYSIS THE CONTEMPORARY STATE OF THE SYSTEM OF TRAINING SPECIALISTS IN RUSSIAN FEDERATION

The review expounds the main content issues of biological safety in the modern period. Theproblems of postgraduate education in the field of biological safety through professional retraining and advanced training programs, as well as training of highly qualified specialists were discussed. The need to form a separate specialty “Biological Safety”for specialists in medical and biological profiles was noted

The Development of Electronic Payment Systems in Ukraine and Their Security

The paper is devoted to the study of innovations in the market of modern payment systems. The pandemic and quarantine restrictions have accelerated the expansion of the payment infrastructure in Ukraine, which in turn raises the issue of security of electronic payment systems. Ukrainians are more actively switching to electronic payments. At the same time, the trend of growing popularity of contactless payment instruments and settlements with them continues. A comparative analysis of the security of payment systems using electronic technologies in the implementation of money transfer services in Ukraine has been performed. The components of the payment system, information security measures in the electronic payment system have been also considered. The schema of electronic payments and the block diagram of the information protection subsystem of electronic payment system have been constructed. The criteria for assessing the security of the electronic payment system have been determined. A total of fifteen safety criteria have been identified, they are divided into six groups according to the degree of safety. Six electronic system payments were used for the study and the research results have been presented in this paper. The tendencies of development of electronic payment systems in modern conditions and ways of improvement of their activity taking into account the newest information technologies have been outlined

Switching of Burkholderia pseudomallei colony morphotypes in stationary condition and in the organism of experimental animals

Aim. Сharacterization of Burkholderia pseudomallei 110 morphotypes, obtained under various cultivation conditions, studying phenotypic characteristics and switching of colony morphology after removal of stress and in the organism of experimental animals. Materials and methods. Morphotypes were induced by passage of B. pseudomallei 110 in LB, sterile river water and in Tetrahymena pyriformis cells, identified on Ashdown medium,  classified according to Chantratita et al., some phenotypic characteristics have been determined. Cultures of morphotypes  were stored for 6-10 months  in 0,4% Nutrient  agar under liquid petrolatun  and colony morphology  was analyzed. Results. Seven morphotypes  of colonies were identified and designated I Chl, II, III Chl, IV Chl, V, VI, and VII Chl. The variability of morphotypes  and their ratio depended  on cultivation conditions.  Morphotypes  were distinguished by the activity of extracellular enzymes, mobility, characterized by increase of porin proteins production, variation in protein mass-spectrums, and decrease of virulence. From animals infected with all morphotypes  was obtained I Chl morphotype; during storage, all cultures acquired the structure of morphotype  VI (VII Chl) of the original strain, similar enzymatic activity and partially restored virulence. Conclusion. The morphotype  VI (VII Chl) B. pseudomallei 110 under stress conditions  gives rise to 5 other morphotypes  that in the animals are switched to the morphotype  I Chl; after removal of the stressful effect they are reverted to the initial morphological variant and its phenotypic properties are restored

Phenotypic Peculiarities of Pathogenic <i>Burkholderia</i> Mutants Resistant to Fluoroquinolones and Cephalosporins

Examined were phenotypic peculiarities of mutants of Burkholderia phylogenetically-related pathogenic species (B. pseudomallei, B. mallei, B. cepacia) resistant to fluoroquinolones and cephalosporins. It was shown that strains with PfxR (OfxR), CfzR markers acquire high multi-drug resistance to antibiotics of different classes. Strain resistance changes under blocking influence of verapamil - inhibitor of calcium membrane channels. Mutant strains differ in production of extracellular enzymes (proteases, lecithinase, lipase) and virulence

APPLICATION OF MONOCLONAL ANTIBODY-BASED LATEX AGGLUTINATION TEST FOR DETECTION AND IDENTIFICATION OF THE AGENT OF MELIOIDOSIS IN CLINICAL AND ENVIRONMENTAL OBJECTS

The review summarizes the basic information on the development and diagnostic capabilities of the latex agglutination test (LAT), used for detection and subsequent identification of melioidosis pathogen. According to the published literature, the use of melioidosis monoclonal antibodies of various epitope direction for coat the latex beads (suspension carrier), the main detection ingredient of this reaction, contributes to an increase in the diagnostic capabilities of this method: its sensitivity and specificity, which has been repeatedly confirmed by specialists working both in endemic zone distribution of Burkholderia pseudomallei and outside these territories. As most authors of the publications noted, after introduction of this reaction into practical work of profile laboratories, low-cost commercial products (test set of reagents for latex agglutination reaction) can find wide application both in stationary and mobile laboratories. The undoubted merits of the method are its simplicity, clarity, suitability for working with various samples from objects of the external environment and biological material, as well as obtained evidence ofthe suitability of LAT to ensure effective differentiation of B. pseudomallei from avirulent related bacteria and detection of the causative agent in the early stages of the disease for relatively short intervals, which makes it a promising method for diagnosing melioidosis, a potentially fatal infection requiring an early onset appropriate antibiotic therapy

IDENTIFICATION OF CAUSATIVE AGENTS OF GLANDERS AND MELIOIDOSIS BASED ON PRINCIPLES OF POLYPHASE TAXONOMIC APPROACH

Aim. Determine an optimal set of the most effective methods of identification and intraspecies typing of causative agents of glanders and melioidosis. Materials and methods. Bacteriologic, immunochemical, molecular-genetic methods were used. Results. A possibility to identify collection strains of pathogenic and closely related Burkholderia in semiautomatic systems is studied. Means of detection of informative variable genome segments of the specified microorganisms were developed, methods of their genetic typing were selected. Effectiveness of application of precipitating mAbs for differentiation of Burkholderia was established. Data on diagnostic possibilities of immunoglobulins fluorescing based on monoclonal antibodies of various etiotropic directionality for detection and identification of B. mallei and B. pseudomallei are generalized. Experimental series of amplification test-systems for identification of glanders and melioidosis causative agents in real-time PCR format are created. Conclusion. A number of methods for identification and typing of glanders and melioidosis causative agents is proposed