Negative control of flagellum synthesis in Pseudomonas aeruginosa is modulated by the alternative sigma factor AlgT (AlgU).
نویسندگان
چکیده
Many respiratory isolates of Pseudomonas aeruginosa from cystic fibrosis patients are mucoid (alginate producing) yet lack flagella. It was hypothesized that an alginate regulator inhibits flagellar gene expression. Mutations in algB, algR, and algT resulted in nonmucoid derivatives, yet algT mutants expressed flagella. AlgT-dependent control of flagellum synthesis occurred through inhibition of fliC but not rpoN transcription.
منابع مشابه
The alternative sigma factor AlgT represses Pseudomonas aeruginosa flagellum biosynthesis by inhibiting expression of fleQ.
Pseudomonas aeruginosa poses a serious risk in individuals suffering from cystic fibrosis (CF). Strains colonizing the CF lung are generally motile but frequently convert to a nonmotile phenotype as the disease progresses. In many cases, this is coordinately regulated with the overproduction of the exopolysaccharide alginate. Both the expression of alginate (mucoidy) and the loss of flagellum s...
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Pseudomonas aeruginosa is a microorganism associated with the disease cystic fibrosis. While environmental P. aeruginosa strains are generally nonmucoid and motile, isolates recovered from the cystic fibrosis lung frequently display a mucoid, nonmotile phenotype. This phenotypic conversion is mediated by the alternative sigma factor AlgT. Previous work has shown that repression of fleQ by AlgT ...
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AlgZ controls Pseudomonas aeruginosa alginate synthesis by activating algD, yet algZ expression is not detectable in nonmucoid strains. Mobility shift and Western blot assays revealed that algZ expression requires the sigma factor AlgT. The mapped algZ transcription start site revealed a consensus AlgT-dependent promoter that, when mutated, substantially reduced algZ transcription.
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Pseudomonas aeruginosa is a Gram negative, opportunistic pathogen that uses the overproduction of alginate, a surface polysaccharide, to form biofilms in vivo. Overproduction of alginate, also known as mucoidy, affords the bacterium protection from the host's defenses and facilitates the establishment of chronic lung infections in individuals with cystic fibrosis. Expression of the alginate bio...
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Azotobacter vinelandii is a nitrogen-fixing soil bacterium that undergoes differentiation to form cysts resistant to desiccation. Upon encystment, this bacterium becomes non-motile. As in enteric bacteria, motility in A. vinelandii occurs through the use of peritrichous flagella. Pseudomonas aeruginosa, a phylogenetically close relative of A. vinelandii, possesses a single polar flagellum. The ...
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ورودعنوان ژورنال:
- Journal of bacteriology
دوره 181 23 شماره
صفحات -
تاریخ انتشار 1999