Genes of resistance to aminoglycoside antibiotics in clinical strains of Serratia marcescens and the enzyme encoded by them]

The patterns of aminoglycoside inactivating enzymes were determined by AGRP in 31 clinical isolated of Serratia marcescens. The results were compared with the data on identification of the aminoglycoside resistance genes by the specific DNA probes. It was shown that all the isolates of Serratia marcescens contained the AAC(6')-Ic gene which was not expressed in some isolates. The other detected aminoglycoside inactivating enzymes were the following: AAC(3)-V in 17 isolates, ANT(2') in 7 isolates, AAC(3)-I in 4 isolates and APH(3')-I in 13 isolates. Reliability of the methods of AGRP and DNA-DNA hybridization was estimated in the assay of the aminoglycoside resistant clinical strains of Serratia marcescens.     

Aminoglycoside-inactivating enzymes in strains of Salmonella and genes encoding them

Aminoglycoside resistance patterns of 56 strains isolated from man, cattle and environment were determined. 34 out of 42 gentamicin-resistant strains were shown to produce AAC(3)-II and 7 strains produced ANT(2"). All the 48 kanamycin resistant strains produced APH(3')-I. Spot hybridization of the 42 gentamicin resistant strains with the inner fragment of the aacC2 gene revealed positive signals for all the strains. Hybridization of the 48 kanamycin-resistant strains with the aphA1 gene probe provided positive results in all the strains. The AAC(3)-IV encoding gene was not detected by DNA-DNA hybridization in the strains studied.     

Quantitative dependence of sheep death on dose and dose rate of external gamma-radiation

The results of experimental studies of sheep death at different dose rates of gamma-radiation have been analyzed. Parameters of a mathematical dependence of animal death on the exposure dose and dose rate have been identified. The evaluation of adequacy of the derived equation has demonstrated that the established relationship correctly describes the experimental data in studied dose rate range.     

Long non‐coding RNAs in melanoma

Melanoma is the most lethal cutaneous cancer with a highly aggressive and metastatic phenotype. While recent genetic and epigenetic studies have shed new insights into the mechanism of melanoma development, the involvement of regulatory non‐coding RNAs remain unclear. Long non‐coding RNAs (lncRNAs) are a group of endogenous non‐protein‐coding RNAs with the capacity to regulate gene expression at multiple levels. Recent evidences have shown that lncRNAs can regulate many cellular processes, such as cell proliferation, differentiation, migration and invasion. In the melanoma, deregulation of a number of lncRNAs, such as HOTAIR, MALAT1, BANCR, ANRIL, SPRY‐IT1 and SAMMSON, have been reported. Our review summarizes the functional role of lncRNAs in melanoma and their potential clinical application for diagnosis, prognostication and treatment.     

Protective effect of bixin on carbon tetrachloride-induced hepatotoxicity in rats

Background

The liver is an important organ for its ability to transform xenobiotics, making the liver tissue a prime target for toxic substances. The carotenoid bixin present in annatto is an antioxidant that can protect cells and tissues against the deleterious effects of free radicals. In this study, we evaluated the protective effect of bixin on liver damage induced by carbon tetrachloride (CCl₄) in rats.

Results

The animals were divided into four groups with six rats in each group. CCl₄ (0.125 mL kg^-1 body wt.) was injected intraperitoneally, and bixin (5.0 mg kg^-1 body wt.) was given by gavage 7 days before the CCl₄ injection. Bixin prevented the liver damage caused by CCl₄, as noted by the significant decrease in serum aminotransferases release. Bixin protected the liver against the oxidizing effects of CCl₄ by preventing a decrease in glutathione reductase activity and the levels of reduced glutathione and NADPH. The peroxidation of membrane lipids and histopathological damage of the liver was significantly prevented by bixin treatment.

Conclusion

Therefore, we can conclude that the protective effect of bixin against hepatotoxicity induced by CCl₄ is related to the antioxidant activity of the compound.     

Population migrations and the epidemic process of Flexner and Sonne dysentery

Analysis of the materials from the Khabarovsk Territory for the representative period of 25 years (1956-1980) revealed the influence of the migration of the population on the level and dynamics of morbidity in different kinds of dysentery, Flexner's dysentery shown to occur more frequently than Sonne dysentery. Intensive migrations increase the proportion of susceptible persons among the population, thus facilitating the formation and circulation of Shigella strains with pronounced virulence.     

Natural population migration and the dysentery epidemic process

The complex analysis of materials obtained in different regions and territories of the Far East makes it possible to establish that the natural migration of population affects dysentery morbidity by enhancing the susceptibility of human population to this infection. The internal mechanisms of the influence exerted on morbidity by the natural migration of population is disclosed from the viewpoint of the theory of the self regulation of the epidemic process.     

The new facultatively chemolithoautotrophic, moderately halophilic, sulfate-reducing bacterium Desulfovermiculus halophilus gen. nov., sp. nov., isolated from an oil field

The new mesophilic, chemolithoautotrophic, moderately halophilic, sulfate-reducing bacterium strain 11-6 could grow at a NaCl concentration in the medium of 30-230 g/l, with an optimum at 80-100 g/l. Cells were vibrios motile at the early stages of growth. Lactate, pyruvate, malate, fumarate, succinate, propionate, butyrate, crotonate, ethanol, alanine, formate, and H2 + CO2 were used in sulfate reduction. Butyrate was degraded completely, without acetate accumulation. In butyrate-grown cells, a high activity of CO dehydrogenase was detected. Additional growth factors were not required. Autotrophic growth occurred, in the presence of sulfate, on H2 + CO2 or formate without other electron donors. Fermentation of pyruvate and fumarate was possible in the absence of sulfate. Apart from sulfate, sulfite, thiosulfate, and elemental sulfur were able to serve as electron acceptors. The optimal growth temperature was 37 degrees C; the optimum pH was 7.2. Desulfoviridin was not detected. Menaquinone MK-7 was present. The DNA G+C content was 55.2 mol %. Phylogenetically, the bacterium represented a separate branch within the cluster formed by representatives of the family Desulfohalobiaceae in the subclass Deltaproteobacteria. The bacterium was assigned to a new genus and species, Desulfovermiculus halophilus gen. nov., sp. nov. The type strain is 11-6T (= VKM B-2364), isolated from the highly mineralized formation water of an oil field.