Escherichia coli biofilm formation and control by phenolic compounds from Salvia officinalis L. extracts

Biofilm is recognized as one of the virulence factors of uropathogenic Escherichia coli. It offers bacteria significantly increased tolerance to antibiotics and makes difficulties in infection eradication. In this study, the biofilm formation ability of clinical isolates of uropathogenic E. coli as well as the antibiofilm activity of the common Garden sage, Salvia officinalis L. extracts were investigated in vitro. The influence of growth conditions (nutrient composition and incubation period) on biofilm formation of E. coli strains was evaluated using crystal violet staining procedure. The tested strains better formed biofilms after a longer incubation period (48 h). In addition, biofilm formation depended on nutrient medium composition. The eight strains were slime producers (Congo red agar assay). The water, ethanol, acetone and diethyl ether S. officinalis extracts were screened for their ability to inhibit the formation and metabolic activity of E. coli biofilms using crystal violet and resazurin assay, respectively. The water extract was not active, while ethanol, acetone and diethyl ether extract exhibited antibiofilm activity (MBIC= 2.5-10 mg/mL). The microscopic visualization of treated E. coli LM1 biofilm has shown morphological and density changes. In addition, the concentrations of phenolic compounds were determined spectrophotometrically. The highest content of total phenolics was found in acetone extract while the flavonoids in water extract.

AUTONOMY SUPPORT, CONTROLLED COACHING STYLES AND SKILLS DEVELOPMENT IN WATER POLO

. Self-determination theory suggests that a coach’s behavior can be viewed in terms of two interpesonal styles: autonomy supportive and controlling. This study was carried out in order to reveal possible connection between coaching styles and improvement in water polo sports practice. During three months period, two experimental groups of young male athletes practicing water polo (each N=10), age ranged 5 to 12, were under special coaching treatment (autonomy supportive or controlled). Autonomy supportive style exibits taking the athletes perspective and providing explanatory rationales when prescribing action, provide much choice as possible in the situation. Controlled coaching style means assigning tasks and activities without the input of the subordinates, showing little interest in how athletes see things, and assuming mantle of infallibility and imperviousness to questioning. Before, and at the end of experimental period, athletes from both groups were measured for speed swimming, and have been graded for performing on two water polo techniques. Age of each participant and experience in water polo practice were taken into account. M, SD, t-test, Anova and correlation analysis were applied. Statistical analysis revealed that both groups of young athletes made statistically significant improvement, although there is no statistical significance between groups. It can be said that sports trainging itself, made improvement of performance in given tests. But, there are some indications that acquisition of speed performance is more suited with controlled coaching style, while autonomy supportivness is providing better climate for developing water polo techniques

Genetic structure of black poplar (Populus nigra l.) Population in the area of great war island

The genetic structure of black poplar (Populus nigra L.) populations in the area of Great War Island (GWI) was studied at the level of 30 genotypes, based on microsatellite molecular markers (SSR). Eleven polymorphic SSR loci were used for analysis of intarpopulation genetic variability. Observed and expected heterozygosity in studied population were high (0.70 and 0.82). The fixation index calculated for single locus ranged from - 0.055 (PMGC_14) up to 0.424 (PMGC_2607), while the mean value was 0.143. Deviation from Hardy- Weinberg equilibrium (HWE) differed between single loci. Stabile genetic structure and satisfactory level of genetic variability that have been determined at the population level represent a good starting point for conservation and sustainable use of the available gene pool and further breeding of this species

Contents of nickel, zinc, copper and lead in agricultural soils of the plains in the northwestern part of the Republic of Srpska

This paper presents the results and methodology of investigation conducted on agricultural soils of the plains in the northwest Republic of Srpska, aiming to determine the extent of heavy metals contamination: nickel (Ni), zinc (Zn), copper (Cu) and lead (Pb). The investigation included 140 soil samples from 14 sites, where the soil samples were taken on 5 locations, from two layers (depths): arable (0-25 cm) and sub-arable (25-50 cm). The total contents of metals were determined by a method of atomic spectrophotometry after acid digestion (HNO3+H2O2). Organic matter content, CEC and pH were determined by standard agrochemical methods. The total contents of nickel in 78.5% of investigated soil samples were higher than the maximum allowed in the unpolluted soils (50 mg/kg). In 22.86% of the analysed samples, the content of zinc was higher than the maximum allowed in the unpolluted soils (100 mg/kg), while the content of copper and lead in the small number of samples was higher than the allowed maximum. Acidic soil reaction (pH<5.5) that increased bioavailability of metals was found in 38.6% of the samples investigated. A high degree of correlation was determined between the total content of certain metals (Cu and Ni, Cu and Zn). This suggests their common origin in the investigated area. The average contents of investigated metals in different layers (depths) were slightly different, having determined higher concentrations of Ni and Cu in the sub-arable layer that indicated the dominance of natural, geochemical sources of these metals in the soils. Territorial distribution of samples with high content of Ni and Zn corresponds to geological substrates which include mineralsnatural carriers of Ni and Zn. This also indicates probable geochemical origin of these elements in the investigated soils. High contents of metals and acid soil reaction indicate that it is necessary to continue research in order to determine the risk of increased transfer of heavy metals from soil to the crops grown

Contents of nickel, zinc, copper and lead in agricultural soils of the plains in the northwestern part of the Republic of Srpska

This paper presents the results and methodology of investigation conducted on agricultural soils of the plains in the northwest Republic of Srpska, aiming to determine the extent of heavy metals contamination: nickel (Ni), zinc (Zn), copper (Cu) and lead (Pb). The investigation included 140 soil samples from 14 sites, where the soil samples were taken on 5 locations, from two layers (depths): arable (0-25 cm) and sub-arable (25-50 cm). The total contents of metals were determined by a method of atomic spectrophotometry after acid digestion (HNO3+H2O2). Organic matter content, CEC and pH were determined by standard agrochemical methods. The total contents of nickel in 78.5% of investigated soil samples were higher than the maximum allowed in the unpolluted soils (50 mg/kg). In 22.86% of the analysed samples, the content of zinc was higher than the maximum allowed in the unpolluted soils (100 mg/kg), while the content of copper and lead in the small number of samples was higher than the allowed maximum. Acidic soil reaction (pH<5.5) that increased bioavailability of metals was found in 38.6% of the samples investigated. A high degree of correlation was determined between the total content of certain metals (Cu and Ni, Cu and Zn). This suggests their common origin in the investigated area. The average contents of investigated metals in different layers (depths) were slightly different, having determined higher concentrations of Ni and Cu in the sub-arable layer that indicated the dominance of natural, geochemical sources of these metals in the soils. Territorial distribution of samples with high content of Ni and Zn corresponds to geological substrates which include minerals- natural carriers of Ni and Zn. This also indicates probable geochemical origin of these elements in the investigated soils. High contents of metals and acid soil reaction indicate that it is necessary to continue research in order to determine the risk of increased transfer of heavy metals from soil to the crops grown

Genetic structure of black poplar (Populus nigra L.) population in the area of Great War Island

The genetic structure of black poplar (Populus nigra L.) populations in the area of Great War Island (GWI) was studied at the level of 30 genotypes, based on microsatellite molecular markers (SSR). Eleven polymorphic SSR loci were used for analysis of intarpopulation genetic variability. Observed and expected heterozygosity in studied population were high (0.70 and 0.82). The fixation index calculated for single locus ranged from -0.055 (PMGC_14) up to 0.424 (PMGC_2607), while the mean value was 0.143. Deviation from Hardy-Weinberg equilibrium (HWE) differed between single loci. Stabile genetic structure and satisfactory level of genetic variability that have been determined at the population level represent a good starting point for conservation and sustainable use of the available gene pool and further breeding of this species