Tag Archives: sulfate-reducing bacteria

Fatty acid composition of sulfate-reducing bacteria isolated from technogenic ecotopes

D. R. Аbdulinа, G. O. Iutynska, L. M. Purish

Danylo Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv;
e-mail: adara@ukr.net

Received: 14 June 2019; Accepted: 15 May 2020

The growth of technogenic (man-caused) load on the environment leads to the disturbance of natural ecotopes and is a stress factor for the widespread sulfate-reducing bacteria (SRB). Changes of SRB fatty acid composition are considered to be not only one of the mechanisms of adaptation and protection from negative stress but also one of the chemotaxonomic features that can be used as the indicator of bacteria genus and its presence in natural ecotopes. The aim of the work was to determine the  fatty acid composition of sulfate-reducing bacteria  strains isolated from different technogenic ecotopes. The spectrum of 17 fatty acids was determined by gas chromatography-mass spectrometry. The predominance of saturated C14:0, C15:0, C16:0 and C18:0 and the presence of unsaturated C16:1 and C18:1 fatty acids in SRB lipids were demonstrated. Correlation analysis showed that SRB isolated from the same technogenic locations were characterized by substantial similarity of fatty acid profiles despite belonging to different genera. Thus, fatty acid compositions of SRB strains Desulfovibrio sp. K1 and K2 isolated from soils near gas main-pipeline had correlation index r = 0.94 and that Desulfovibrio sp. TC2, Desulfotomaculum sp. TC3 and Desulfomicrobium sp. TC4 isolated from city heat system ecotope had correlation index r = 0.97-0.99. The obtained data on increased saturation degree of SRB fatty acids and decreased membrane fluidity indexes could be used for assessing the degree of SRB adaptation to the influence of man-caused loading as a stress factor.

Glutathione level of Desulfovibrio desulfuricans ІМV K-6 under the influence of heavy metal salts

I. V. Kushkevych, S. O. Hnatush, H. V. Mutenko

Ivan Franko Lviv National University, Ukraine;
e-mail: Ivan_Kushkevych@ukr.net

Glutathione is the metal stress protector and changes of its level in the sulfate-reducing bacteria cells under the influence of heavy metal salts have not been studied yet. CdCl2, Pb(NO3)2, CuCl2, and ZnCl2 influence on the total glutathione level in cell-free extracts of sulfate-reducing bacteria Desulfovibrio desulfuricans ІМV K-6 was studied. The research has been carried out using Ellman, Lowry methods, statistical processing of the results. It was shown that the glutathione level depends on the heavy metal salts concentration in the medium. The total glutathione level was the highest under the influence of Pb(NO3)2. Other salts were also toxic to bacteria because glutathione level increased in bacterial cells after addition of these salts to the medium. On the basis of the results of our work the range of heavy metal salts influence on D. desulfuricans ІМV K-6 cells glutathione level has been formed for the first time: Pb(NO3)2 > CuCl2 > CdCl2 > ZnCl2.

Kinetic properties of adenosine triphosphate sulfurylase of intestinal sulfate-reducing bacteria

I. V. Kushkevych1,2, H. L. Antonyak3, M. Bartoš2

1Institute of Animal Biology, NAAS of Ukraine, Lviv;
2University of Veterinary and Pharmaceutical Sciences of Brno, Czech Republic;
3Ivan Franko National University of Lviv, Ukraine;
e-mail: ivan.kushkevych@gmail.com

The investigation of specific activity of ATP sulfurylase and kinetic properties of the enzyme in cell-free extracts of intestinal bacterial strains Desulfovibrio piger Vib-7 and Desulfomicrobium sp. Rod-9 is presented. The microbiological, biochemical, biophysical and statistical methods were used in the work. The optimal temperature (35 ºC) and pH 8.0-8.5 for enzyme reaction were determined. An analysis of kinetic pro­perties of ATP sulfurylase has been carried out. Initial (instantaneous) reaction velocity (V0), maximum amount of the product of reaction (Pmax), the reaction time (half saturation period, τ) and maximum veloci­ty of the ATP sulfurylase reaction (Vmax) have been defined. Michaelis constants (KmSulfate, KmATP, KmAPS, and KmPyrophosphate­) of the enzyme reaction were demonstrated for both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains.