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Daria I. Bagaeva, Galina R. Demina, Mikhail O. Agaphonov, Alexander P. Savitsky, Arseny S. Kaprelyants, Margarita O. Shleeva
Methylation
of coproporphyrin as a protective mechanism in mycobacteria under adverse
conditions
Abstract
Abstract. The transition of active Mycolicibacterium smegmatis cells to a
dormant state under acidification conditions is associated with intracellular
accumulation of coproporphyrin tetramethyl ether (TMC). At the same time,
dormant forms of mycobacteria develop resistance to a number of damaging
factors. The addition of 5-aminolevulinic acid (ALA), a precursor of porphyrin
synthesis, into the bacterial culture medium leads to the accumulation of TMC
in actively growing cells, that simulates the situation with dormant
mycobacteria. With an increase in the concentration of TMC by 3 times, the
bacteria become 7 times more resistant to the action of 40 mM hydrogen peroxide
and 90 times more resistant to heating up to 80 °C. At the same time, in M.
smegmatis cells with an increased content of TMC, the activity of
dichlorophenolindophenol reductase, which is a marker of respiratory chain
activity, decreases by 18%. The detected inhibition of activity can lead to a
decrease in side oxidative reactions in the cell. Thus, the accumulation of
methylated coproporphyrin is possible to be one of the mechanisms for the
development of mycobacterium resistance at dormancy.
Key words: mycobacteria, tetramethyl ether of coproporphyrin, oxidative stress,
5-aminolevulinic acid
Copyright (C) Chemistry Dept., Moscow State University, 2002
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