Induction of the viable but nonculturable state of Salmonella enterica serovar Enteritidis deficient in (p)ppGpp synthesis.
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Date
2015
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Abstract
Salmonella enterica enters a viable but
nonculturable (VBNC) state in adverse environmental conditions.
Under nutritional stress, RelA and SpoT proteins synthesize
(p)ppGpp, a molecule that controls the expression of
genes important for the survival of a cell under those conditions.
This study aimed to verify the involvement of (p)ppGpp
in the entry of S. enterica serovar Enteritidis PT4 578 cells
into the VBNC state by evaluating ΔrelA and ΔrelAΔspoT
mutants. The wild-type and mutant strains deficient in
(p)ppGpp synthesis were subjected to osmotic, nutritional
and cold stress, after which the cells entered a VBNC state
at different time periods, concurrent with reductions in cell
diameter, volume and length, and conversion from a bacillary
to a coccoid form. No difference in the culturability or cell
viability of the wild-type and single and double mutants was
observed. Expression of the rpoS gene was increased in the
double mutant, while both mutant strains presented a reduction
in mreB gene expression after 25 days under conditions of
nutritional and cold stress. Surprisingly, (p)ppGpp was not
necessary for induction of the VBNC state in Salmonella
PT4 578 cells, but may be associated with regulation of genes
that control septum formation during cell division, maintaining
the bacillary cell morphology (mreB) and stress response
(rpoS). Our findings contribute to the understanding of the
mechanisms of resistance and survival of Salmonella under
adverse conditions.
Description
Keywords
Stringent response, Cell filamentation, Septum formation
Citation
RODRIGUES, R. C. et al. Induction of the viable but nonculturable state of Salmonella enterica serovar Enteritidis deficient in (p)ppGpp synthesis. Annals of Microbiology, v. 65, p. 2171-2178, 2015. Disponível em: <https://link.springer.com/article/10.1007/s13213-015-1057-6>. Acesso em: 05 ago. 2017.