Publications (7) View all
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Article: Application of CZE in the Differentiation of Staphylococcus aureus Strains.
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ABSTRACT: Precise, fast, and cheap identification of pathogenic bacteria is a key factor of microbial diagnostics. Application of analytical techniques can provide new possibilities in this regard. The bacterial pathogen Staphylococcus aureus is responsible for a number of serious human infections which are hard for eradication since the number of multidrug resistant isolates is increasing. In the present chapter, we describe novel methods based on capillary zone electrophoresis (CZE) and (as confirmation of these results) molecular analysis of a part of the coag gene for identification and differentiation of S. aureus strains.Methods in molecular biology (Clifton, N.J.) 01/2013; 919:149-54. -
Article: Study of charge distribution on the surface of biocolloids.
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ABSTRACT: Potentiometric titration and zeta potential measurements are crucial techniques for the characterization of the surface properties of bacterial cells. In this study, we investigated the effects of two commonly used electrolytes, NaNO(3) and NaClO(4), on the viability and acid-base properties of Gram-positive bacteria Bacillus subtilis. B. subtilis are non-pathogenic bacteria which are often used to model the surface properties of pathogenic microorganisms of the same genus, including Bacillus anthracis and Bacillus cereus. The survival rates of bacterial cells treated with NaNO(3) were significantly higher in comparison with microorganisms treated with NaClO(4) (5.2-6.8 and 4.1-4.7log(10)cfu - colony-forming units, respectively). A decrease in the ionic strength (0.1M, 0.01M and 0.005M) of both electrolytes increased viable bacterial cell counts in NaNO(3) treatments and decreased viable bacterial counts in NaClO(4) treatments. Potentiometric titration revealed three dominant types of cell wall functional groups: the carboxyl group (pK(a) values of 4.58-4.89), the amino group (pK(a) values of 9.62-9.89) and the phosphate group (pK(a) values of 7.12-7.49). An increase in the ionic strength of electrolytes led to a decrease in total site concentrations and a drop in buffering capacity at the examined pH values. Based on zeta potential values, measured as a function of pH and ionic strength, the isoelectric point of B. subtilis was determined at pH 2.2 for 0.005M and 0.01M NaNO(3). Zeta potential increased with a rise in pH, and it decreased with an increase in ionic strength.Colloids and surfaces. B, Biointerfaces 11/2012; 104C:122-127. · 2.60 Impact Factor -
Article: EFFECT OF APPLIED VOLTAGE ON VIABILITY OF BACTERIA DURING SEPARATION UNDER ELECTROPHORETIC CONDITIONS
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ABSTRACT: Simple quantitative tests were performed to assess the viability of bacteria cells during capillary electrophoretic process. The results have shown that Gram-negative E. coli cells were more sensitive to electric field treatment in comparison to Gram-positive S. aureus. In comparison to a reference sample (0 kV) only 3.4% and 0.7% of the E. coli cells survived the applied voltage treatment (20 kV and 30 kV, respectively). S. aureus strains were more resistant to the electric field: 33–35% and 10–30% survived voltage of 20 and 30 kV, respectively. Such significant differences can be attributed to different cell wall composition where more peptidoglycan layers present in Gram-positive cells make them more rigid and resistant to external conditions.Journal of Liquid Chromatography & Related Technologies 12/2011; 34(20):2689-2698. · 0.71 Impact Factor -
Article: Determination of volatile organic compounds in human breath for Helicobacter pylori detection by SPME-GC/MS.
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ABSTRACT: Helicobacter pylori living in the human stomach release volatile organic compounds (VOCs) that can be detected in expired air. The aim of the study was the application of breath analysis for bacteria detection. It was accomplished by determination of VOCs characteristic for patients with H. pylori and the analysis of gases released by bacteria in suspension. Solid-phase microextraction was applied as a selective technique for preconcentration and isolation of analytes. Gas chromatography coupled with mass spectrometry was used for the separation and identification of volatile analytes in breath samples and bacterial headspace. For data calculation and processing, discriminant and factor analyses were used. Endogenous substances such as isobutane, 2-butanone and ethyl acetate were detected in the breath of persons with H. pylori in the stomach and in the gaseous mixture released by the bacteria strain but they were not identified in the breath of healthy volunteers. The canonical analysis of discrimination functions showed a strong difference between the three examined groups. Knowledge of substances emitted by H. pylori with the application of an optimized breath analysis method might become a very useful tool for noninvasive detection of this bacterium.Biomedical Chromatography 03/2011; 25(3):391-7. · 1.97 Impact Factor -
Article: Effect of zeta potential value on bacterial behavior during electrophoretic separation.
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ABSTRACT: The aggregation and/or adhesion of bacterial cells is a serious disadvantage of electrophoretic separations. In this study, physicochemical surface characteristics of bacteria were measured to establish their role in bacterial adhesion and aggregation on the basis of electrophoretic behavior of different clinical strains of Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. The number and the shape of peaks obtained on the electropherograms were connected with the zeta potential measurements and in-line microscope observation using specially designed CE fluorescence stereomicroscope setup. These results suggest that the lower the zeta potential, the higher the number of smaller peaks detected. The direct microscopic observation of electrophoretic movement proved the presence of many small aggregates originating from individual or clustered bacterial cells. On the other hand, lower zeta potential was also observed for dead bacterial cells, which suggested that some of the peaks can be attributed to viable cells while the other to the dead ones.Electrophoresis 05/2010; 31(9):1590-6. · 3.30 Impact Factor
