Comparison of the Adaptive Potential of the Arthrobacter oxydans and Acinetobacter lwoffiiIsolates from Permafrost Sedimentary Rock and the Analogous Collection Strainsстатья
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Аннотация:A comparative study was conducted on the adaptive mechanisms of the strains Arthrobacter oxy-
dans K14 and Acinetobacter lwoffii EK30A isolated from permafrost subsoil sediments and of those of the anal-
ogous collection strains (Ac-1114 Type and BSW-27, respectively). In each pair of the strains compared, the
strains differed in terms of (i) growth-related, physiological, and biochemical properties; (ii) resistance to stress
factors; (iii) capacity for generation of dormant forms (DFs) under growth arrest conditions, and
(iv)intrapopulation production of phase variants. The strains isolated from permafrost displayed a lower growth
rate but were more resistant to repeated freezing–thawing treatment than the collection strains. Under the same
growth conditions, the permafrost strains formed larger numbers of cystlike anabiotic DFs, extraordinarily
small cells, and forms that became nonculturable during long-term storage. Resuscitation of the nonculturable
forms resulted in a 2- to-7-fold increase in the percentage of FISH-detectable metabolically active cells. The
permafrost strains were also distinguished by increased genome lability. This facilitated their dissociation into
intrapopulation variants with phenotypically distinct colonial and morphological properties and different anti-
biotic resistance. The phenotypic variability was more prominent in Arthrobacter (for which it was not reported
previously) than in Acinetobacter. In the populations produced by plating the dormant bacterial forms, the qual-
itative and quantitative characteristics of the phase variant spectra varied depending on the formation conditions
and the composition of the solid media used for the plating. Thus, the permafrost isolates of A. oxydans and Ac.
lwoffii were distinguished from their collection analogs by a more manifest adaptive potential including stress
resistance, the intensity of DF generation under growth arrest conditions, and increased intrapopulation vari-
ability.
Keywords: permafrost subsoil sediments, permafrost isolates, Arthrobacter oxydans, Acinetobacter lwoffii,
adaptive potential, stress resistance, intrapopulation variability, phase variants, dormant forms