Análise do sistema toxina-antitoxina tipo II na fisiologia bacteriana de uma cepa híbrida: Escherichia coli enteropatogênica atípica e E. coli extraintestinal

Abstract

The toxin-antitoxin (TA) systems are genetic modules associated with some bacterial processes, such as cell formation persistence, biofilm formation, protection against bacteriophages and responses to stressful environments. In these systems, the toxin is related to the inhibition of physiological processes and the antitoxin provides protection to the cell against the toxin. Five TA type II systems present in the genome of the hybrid strain BA1250 (atypical enteropathogenic E. coli and extraintestinal E. coli strain) were analyzed. The hybrid strain BA1250 can colonize different host niches and can face different stress environments, therefore, through transcription analysis under stress conditions such as nutritional, oxidative, osmotic and acid, the CcdB-CcdA, YhaV-PrlF, MazF-MazE, YoeB-YefM and PasI-PasT were evaluated both in the log and stationary phases of BA1250 strain. We observed significant differences in the expression levels of the CcdB-CcdA, YhaV-PrlF, YoeB-YefM and PasT-PasI systems in the presence of nutritional stress in the stationary phase. In acid stress, an increase in the gene expression of YhaV, YefM and PasT toxins in stationary phase was observed. In contrast, the analysis of the MazF-MazE system did not show any change in expression levels under the stress conditions evaluated. These data indicate that these four TA systems seem to be involved in the stress response of the BA1250 strain, therefore involved in the physiological processes of BA1250.