RESUMO
The possibility of characterizing fluorescent immunoglobulins using spectrophotometric analysis as a testing method is considered. The comparative analysis of optical properties of fluorescent immunoglobulin preparations and their components-immunoglobulins and fluorochrome-is carried out. The obtained results testify that the proposed methodological approach of optical detection of labeled immunoglobulin molecules can be promising for tests on obtaining conjugates used in immunological tests on revealing specific antigens of causative agents of especially dangerous infections.
RESUMO
Characteristics of the effect of attenuated rabies virus strain «Moscow 3253¼ on morphological parameters of transplantable line Vero cells were studied by atomic force microscopy (AFM). Methods based on phase contrast microscopy and immunofluorescence were used to confirm the specificity of interaction and to identify the infectious activity of the rabies virus. Images of intact Vero cells and Vero cells infected with rabies virus were obtained at different periods of cultivation. The character of changes in the cell dimensions (length, width, height) and the cell membrane roughness depending on the rabies virus cultivation time was determined. During the observation period both increases and decreases in the size of the cells were recorded. The size of the infected cells exceeded that of the intact. An increase in the membrane roughness in cells exposed to rabies occurred during the entire period of observation, since the first hours of the interaction of the virus with the cell, while the intact Vero cells exhibited only minor changes in the membrane surface roughness, which were not dependent on the age of the culture. The dependence of the increase in the cell membrane roughness on the infecting dose of the rabies virus was determined. The obtained results open up the prospect of developing a methodological approach to the quantitative in vitro evaluation of the rabies virus using AFM. Changes in the cell membrane roughness appear to be the most indicative parameter for such evaluation.
RESUMO
AIM: Study the effect of osmotic and oxidative stress on survivability and changes in phenotypic and genetic properties of strains of genovariants of V. cholerae El Tor biovar. MATERIALS AND METHODS: 22 strains of V. cholerae El Tor biovar were used in the study. Phenotypic properties of strains were studied in LB medium with the addition of the appropriate ingredients. Surface structures of cells were studied using scanning probe microscope "Solver P47-PRO". PCR was carried out using specific primers in "Tercic" amplificator. RESULTS: After 60 minutes of incubation in 3 M solution of NaCl and after 6 minutes in 20 mM solution of hydrogen peroxide, the amount of surviving cells of genovariants was, respectively, 3.0 - 25.0 and 4.3 - 7.6 times higher than for typical strains. One of the mechanisms of increased resistance of genovariants to high concentrations of salt was associated with the production of an extra exopolysaccharide layer on the cell surface at earlier periods than in typical strains. Osmotic stress results in a reversible reduction of mobility in strains of genovariants of V. cholerae El Tor biovar. Osmotic and oxidative stress was revealed to result in a loss of a number of mobile genetic elements in strains of genovariants. CONCLUSION: Genovariants of V. cholerae El Tor biovar, that had caused cholera outbreaks in Russia in 1993 -2001, in contrast to typical strains, isolated in 1970 - 1990, are more resistant to th effect of osmotic and oxidative stress, that, probably, facilitates their higher survivability in both the environment and macroorganism.
