Pyrimidine Biosynthesis Regulates the Small-Colony Variant and Mucoidy in Pseudomonas aeruginosa through Sigma Factor Competition.

ABSTRACT: Mucoidy due to alginate overproduction by the Gram-negative bacterium Pseudomonas aeruginosa facilitates chronic lung infections in patients with cystic fibrosis (CF). We previously reported that disruption in de novo synthesis of pyrimidines resulted in conversion to a nonmucoid small-colony variant (SCV) in the mucoid P. aeruginosa strain (PAO581), which has a truncated anti-sigma factor, MucA25, that cannot sequester sigma factor AlgU (AlgT). Here, we showed that supplementation with the nitrogenous bases uracil or cytosine in growth medium complemented the SCV to normal growth, and nonmucoidy to mucoidy, in these mucA25 mutants. This conversion was associated with an increase in intracellular levels of UMP and UTP suggesting that nucleotide restoration occurred via a salvage pathway. I

SUBMITTER: Al Ahmar R 

PROVIDER: S-EPMC6287457 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature