Phylogenetic analysis of the microbial mat in the hot spring Garga (Baikal rift zone) and the diversity of natural peptidases

Hydrolytic bacteria (in particular, proteolytics) are the primary destructors in hot springs. The proteolytic bacteria are able to secrete enzymes that are active in wide ranges of pH and temperature. The aim of this work was to study the taxonomic composition, the structure of the bacterial microbial mat, and to study the distribution of peptidases in the thermophilic microbial Garga community. For the study, we sampled the microbial mat at a water temperature of 54.2 °C and a pH of 8.3. Hydrochemical analysis of water showed a high content of sulfates, 390 mg/dm3. The microelement composition of water showed that the Garga water had increased concentrations of B, Rb, Li, Ba, Sr. We analyzed the taxonomic diversity of the microbial community in the hot spring Garga at a temperature zone of 54 °C. The structure of the microbial mat is represented by various phylogenetic groups of mesophilic and thermophilic bacteria, with various metabolic and ecological functions. The dominant group in this community was the phylum Firmicutes (64 %). The analysis of the collected metagenomic sequences of the microbial community allowed the detected peptidases in the microbial community in the hot spring Garga to be for the first time systematized and characterized. Comparisons of metagenomic sequences of representative data showed a dominance of serine peptidase class enzymes. Natural peptidases in the investigated microbial community ensure the hydrolysis of biopolymers at the first stages of the destruction of organic matter and may have biotechnological relevance

Mechanism of smectic arrangement of montmorillonite and bentonite clay platelets incorporated in gels of poly(acrylamide) induced by the interaction with cationic surfactants

Structure transitions, induced by the interaction with the cationic surfactant cetylpyridinium chloride in nanocomposite gels of poly(acrylamide) with incorporated suspensions of the two closely related layered clays bentonite and montmorillonite, were studied. Unexpectedly, different behaviors were revealed. X-ray diffraction measurements confirm that, due to the interaction with the surfactant, initially disordered bentonite platelets arrange into highly ordered structures incorporating alternating clay platelets and surfactant bilayers. The formation of these smectic structures also in the cross-linked polymer gels, upon addition of the surfactant, is explained by the existence of preformed, poorly ordered aggregates of the clay platelets in the suspensions before the gel formation. In the case of montmorillonite, smectic ordering of the disordered platelets in the presence of the surfactant is observed only after drying the suspensions and the clay-gel composites. Rheology studies of aqueous suspensions of the two clays, in the absence of both surfactant and gel, evidence a much higher viscosity for bentonite than for montmorillonite, suggesting smaller clay-aggregate size in the latter case. Qualitatively consistent results are obtained from optical micrographs

Ultrasound scan of the orbit with an immersion protection in patients with subatrophy and anophthalmos

We observed 73 patients with anophthalmos with different types of intraorbital implants, and subatrophy of the globe. For three- dimensional ultrasound image of the orbit we used a new immersion substation on the basis of compressed polyvinyl alcohol, which was placed between the probe and the eyelids, excluding «dead zone». Acoustic density of the orbital structure and orbital blood flowwere estimated

IMPACT OF COINFECTION OF PV B19 ON THE COURSE AND PROGNOSIS OF MALARIA CAUSED BY PLASMODIUM FALCIPARUM

Parvovirus infection (PVI) is widespread in the world; more than 80% of the adult population have antibodies of IgG class to parvovirus B19. Malaria is a vector-borne parasitic disease caused by the protozoa of the genus Plasmodium, that is widespread in the countries of Africa, Southeast Asia, Oceania. The objective of the present study was to evaluate the effect of parvovirus B19 infection on the clinical course of malaria and the outcome of the underlying disease. During the period 2016–2018 blood plasma samples of 316 patients from the hospital of the Friya Prefecture of the Republic of Guinea (GR) with confirmed diagnosis of malaria were examined for the presence of PVB19 DNA. The clinical course of malaria in 316 examined patients was divided into group of either mild or complicated. In total, PVB19 DNA was detected in blood plasma in 55 of 316 patients (17.41±2.13%). But in the group with co-infection of PVB19 and P. falciparum complications were observed in 40 of 55 (72.73±2.75%) patients, and in 6 of 55 cases (10.91±4.40%) the disease resulted in death. In the group of patients with malaria without PVI, complications occurred in 99 of 261 patients (37.9±3.0%); of those 2 (0.77±0.54%) died. It was found that the most numerous group in the structure of malaria patients is represented by children under 5 (median 3) years (89, or 28.25±2.53%). Our results correlate with the data of other researchers who studied the PVI-associated malaria in children in malaria-endemic regions: among children under 5 years, the absolute majority of cases of PVI was accompanied by a complicated course of malaria. The primary parvovirus infection can aggravate the course of malaria, especially when combined with other unfavorable conditions (iron deficiency, malnutrition, helminthic infections, co-infections, etc.). Thus, infection with PVB19 becomes a critical factor, which can provoke a severe life-threatening anemia, and also cause other complications

INFECTION OF LABOUR MIGRANTS FROM CENTRAL ASIA AND RESIDENTS OF ST. PETERSBURG AND THEIR SUSCEPTIBILITY TO VARIOUS INFECTIOUS DISEASES

Wide migration processes typical for megacities, including St. Petersburg, require a comprehensive study of the infection among migrants arriving on a work visa. Biological material for research was taken from 370 migrants who arrived in St. Petersburg on a work visa. The control group is represented by 320 adults of St. Petersburg. The methodology of the study of the biological material depended on the type of pathogen and included classical and modern methods of research. All obtained data are processed using adequate methods of mathematical statistics. C. diphtheriae strains in migrant workers were isolated 80 times more often than in permanent residents of St. Petersburg. In St. Petersburg gravis biovar occurs in 25% of cases, in the visiting contingent — in 83% of cases, which is an unfavorable prognostic sign. In migrants 17% of C. diphtheriae strains have a “silent” gene (tox+), which, under known conditions, can resume toxin production. The local people are protected from diphtheria by 95%, and labor migrant is only 66%. 17% of migrant workers with C. diphtheriae strains have a low level of protection against diphtheria, which poses a threat to them and those in contact with them. Infection with brucellosis pathogens of labor migrants from Uzbekistan is 9 times higher than the local population, persons from Tajikistan — 60 times higher. The infection rate of migrant workers from Uzbekistan and Tajikistan C. burnetii is 25 times higher than that of the local population. The chronic course of these infections complicates diagnosis and reduces the quality of life. According to the results of the screening test, S. Typhi bacterium carrier is distributed 7 times more in migrant workers from Uzbekistan and 2 times more in persons from Tajikistan than among the local population of St. Petersburg. The seroprevalence of toxic H. pylori in migrant workers is 84%, which is much higher than that of permanent residents of St. Petersburg (57%). The causes of this phenomenon have not been studied and require further study. Labor migrants from Central Asia have a low level of population immunity to parvovirus infection: 37% of seropositive persons from Uzbekistan and 62% from Tajikistan compared with 78% of the local population. This may contribute to the spread of parvovirus infection involving infection of seronegative residents of St. Petersburg risk groups, including blood donors, pregnant women, persons with immunodeficiencies, hematologic and oncologic patients. The results obtained ascertain the tense epidemiological situation among labour migrants in St. Petersburg for a number of infections. Reliable information will help to organize the correct further study of the problem and conduct appropriate measures to preserve the health of the local population and the visiting contingent