Author/Authors :
Tkachenko, Olexiy Dnipro State Agrarian and Economic University, Dnipro, Ukraine , Bilan, Maryna Dnipro State Agrarian and Economic University, Dnipro, Ukraine , Hlebeniuk, Volodymyr Dnipro State Agrarian and Economic University, Dnipro, Ukraine , Kozak, Natali Dnipro State Agrarian and Economic University, Dnipro, Ukraine , Nedosekov, Vitalii National University of Bioresources and Management of Nature of Ukraine , Galatiuk, Olexandr Zhytomyr Agrarian and Ecological University, Ukraine
Abstract :
The article presents the results of investigations concerning the cleavage of avirulent cells from the virulent
epizootic strain Mycobacterium bovis (M. bovis) during the 20 month storage at low positive temperatures (2-3°C).
It was preceded by a 116-fold reinoculation of the suspension of the virulent culture into a dense nutrient medium.
Mycobacteria of the detected colonies have acquired new features and properties. It was noted that in the second and
subsequent generations, mycobacteria appeared in the form of non-acid resistant grains and short rod-shaped bacteria
and L-forms of the protoplastic (spheroplastic) type. The change in morphology was accompanied by the emergence
in mycobacteria of the ability to be grown on chemically simple nutrient media. Different morphological forms of
mycobacteria were found in the elective dense nutrient medium at 3°C and 37°C cultivation: at 3°C irrespective of the
initial morphological forms, non-acid-resistant short rod-shaped bacteria and grains were generated in dynamics; at
37°C – L-shaped protoplastic (spheroplastic) type and elementary small bodies. The appearance of the latter in culture
has changed the nature of its growth. It is shown that qualitative processes of morphological forms of the biological
cycle of mycobacteria occur on the background of quantitative changes in the chemical composition, in particular
lipids. The content of total lipids decreased, at the stability of the quality of the fractions of total lipids. Differences in
the ratio of unsaturated to saturated fatty acids in pathogenic and non-pathogenic mycobacteria have been established.
Long-chain acids with a content of 26-27 carbon atoms, regardless of the temperature of cultivation, disappeared
in the dissociative forms. The biological cycle of the development of dissociative M. bovis at different temperatures
of cultivation with properties distinct from the parent strain, characterizes the wider possibilities of the investigated
microorganism as it is known today
Keywords :
Mycobacterium bovis , Dissociative forms , Low-temperature conditions , Biological properties , Morphology , Lipid
