Dataset Information


Transcriptome of pvcA mutant as compared to parent strain of pseudomonas aeruginosa

ABSTRACT: Pseudomonas aeruginosa is a gram negative pathogen that infects acute wounds such as third degree skin injury and chronic wounds such as diabetic ulcers. Within infection sites, this pathogen exists in specific structures termed as biofilms. Biofilms contribute to enhanced resistance of microorganisms to the host defense and antibiotic treatments. Flagella, pilli and chaperon usher pathway (cup) fimbriae provide initial attachment to host tissue during biofilm development. pvcA-D operon codes for proteins which synthesize a secondary metabolite called paerucumarin. Paerucumarin is an isonitrile functionalized cumarin which is not extensively analyzed. We recently showed that paerucumarin enhances the expression of cup genes and biofilm development. We hypothesize that besides the cup genes pvcA-D operon regulates other P. aeruginosa genes. To test this hypothesis, we compared the transcriptome of P. aeruginosa strain MPAO1 with its pvcA mutant (MPAO1/pvcA). In comparison with MPAO1, 53 genes were differentially expressed in pvcA which included 19 up-regulated and 34 down-regulated genes. Functional characterization of differentially expressed genes indicated that 20 of these genes have been reported as iron regulated genes. Real time PCR confirmed these results and indicated that the expression of pvcAD operon is iron independent. However traditional chrome azurol S (CAS) iron binding assay showed that paerucumarin binds iron either within supernatants of MPAO1 or in solution. In addition, exogenously added paerucumarin enhances the expression of iron repressed genes pvdS and pvdA. Similarly, the level of pvdS gene expression in MPAO1?pvcA was significantly reduced as compared to MPAO1. Further analysis confirmed that paerucumarin binds iron in MPAO1 but does not deliver it inside the cell. The growth of a PAO1 double mutant strain (?pvdD?pchA), defective in iron scavenging systems, grown in iron deficient medium was restricted. However, the growth was restricted even further upon addition of exogenous paerucumarin to bacterial cultures. These results suggest that paerucumarin chelates iron but does not function as an iron scavenging system. 4 biological replicates of each strain were randomly paired

ORGANISM(S): Pseudomonas aeruginosa  

SUBMITTER: Muhammed Azeem   Abdul Hamood  Uzma Qaisar 

PROVIDER: E-GEOD-45973 | ArrayExpress | 2014-01-01



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