ترجمه مقاله نقش ضروری ارتباطات 6G با چشم انداز صنعت 4.0
- مبلغ: ۸۶,۰۰۰ تومان
ترجمه مقاله پایداری توسعه شهری، تعدیل ساختار صنعتی و کارایی کاربری زمین
- مبلغ: ۹۱,۰۰۰ تومان
The exopolyphosphatase (Ppx) of Pseudomonas aeruginosa is encoded by PA5241 gene (ppx). Ppx catalyzes the hydrolysis of inorganic polyphosphates (polyPs) to orthophosphate (Pi). In the present work we identified and characterize the promoter region of ppx and its regulation under environmental stress conditions. The role of Ppx in the production of several virulence factors was demonstrated through studies performed on a ppx null mutant. We found that ppx is under the control of two interspaced promoters, dually regulated by nitrogen and phosphate limitation. Under nitrogen-limiting conditions its expression was controlled from a σ 54-dependent promoter activated by the response regulator NtrC. On the other hand, under Pi limitation the expression was controlled from a σ 70 promoter, activated by PhoB. Results obtained from the ppx null mutant demonstrate that Ppx is involved in the production of virulence factors associated with both acute infection (e.g., motility-promoting factors, blue/green pigment production, C6-C12 quorum-sensing homoserine lactones) and chronic infection (e.g., rhamnolipids, biofilm formation). Molecular and physiological approaches used in this study indicate that P. aeruginosa consistently maintains proper levels of Ppx regardless of environmental conditions. The precise control of ppx expression appears to be essential for the survival of P. aeruginosa and the ocurrence of either acute or chronic infection in the host.