Unknown,Transcriptomics,Genomics,Proteomics

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Functional redundancy of iron acquisition systems is required for Proteus mirabilis pathogenesis during UTI

ABSTRACT: Proteus mirabilis is a primary cause of complicated urinary tract infections (UTI). Surprisingly, iron acquisition systems have been poorly characterized in this uropathogen despite the urinary tract being iron-limited. In this report the transcriptome of strain HI4320, cultured under iron limitation, was examined using microarray analysis. Of genes upregulated at least 2-fold, 45 were statistically significant and comprise 21 putative iron-regulated systems. Two of these systems, PMI0229-0239 and PMI2596-2605, are organized in operons and appear to encode siderophore biosynthesis genes. Five microarrays comparing P. mirabilis HI4320 cultured in LB broth to P. mirabilis cultured in LB broth + 15 uM Desferal (an iron chelator) were analyzed. All five arrays are biological replicates; arrays #2 and 4 are dye swaps.

ORGANISM(S): Proteus mirabilis HI4320

SUBMITTER: Melanie Pearson

PROVIDER: E-GEOD-18051 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Proteobactin and a yersiniabactin-related siderophore mediate iron acquisition in Proteus mirabilis.

Himpsl Stephanie D SD Pearson Melanie M MM Arewång Carl J CJ Nusca Tyler D TD Sherman David H DH Mobley Harry L T HL

Molecular microbiology 20101001 1

Proteus mirabilis causes complicated urinary tract infections (UTIs). While the urinary tract is an iron-limiting environment, iron acquisition remains poorly characterized for this uropathogen. Microarray analysis of P. mirabilis HI4320 cultured under iron limitation identified 45 significantly upregulated genes (P ≤ 0.05) that represent 21 putative iron-regulated systems. Two gene clusters, PMI0229-0239 and PMI2596-2605, encode putative siderophore systems. PMI0229-0239 encodes a non-ribosomal ...[more]

PMID: 20923418

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Project description:The enteric bacterium Proteus mirabilis is a common cause of complicated urinary tract infections. In the study, microrarrays were used to analyze P. mirabilis gene expression in vivo from experimentally infected mice. Urine was collected at 1, 3, and 7d postinfection, and RNA was isolated from bacteria in the urine for transcriptional analysis. Across 9 microarrays, 471 genes were upregulated and 82 were downregulated in vivo compared to in vitro broth culture. Genes upregulated in vivo encoded MR/P fimbriae, urease, iron uptake systems, amino acid and peptide transporters, pyruvate metabolism, and portions of the TCA cycle. Flagella were downregulated. Ammonia assimilation gene glnA (glutamine synthetase) was repressed in vivo while gdhA (glutamate dehydrogenase) was upregulated in vivo. Contrary to our expectations, ammonia availability due to urease activity in P. mirabilis did not drive this gene expression. A gdhA mutant was growth-deficient in minimal medium with citrate as the sole carbon source, and loss of gdhA resulted in a significant fitness defect in the mouse model of urinary tract infection. Unlike Escherichia coli, which represses gdhA and upregulates glnA in vivo and cannot utilize citrate, the data suggest that P. mirabilis uses glutamate dehydrogenase to monitor carbon-nitrogen balance, and this ability contributes to the pathogenic potential of P. mirabilis in the urinary tract. Voided urine from female CBA/J mice infected with Proteus mirabilis was collected and pooled in RNA stabilizing reagent (RNAprotect). Urine was collected at 1, 3, and 7 d postinfection. RNA was isolated from urine and log-phase LB cultures, converted to cDNA, and labeled with CyDye. Three arrays were completed per time point (9 arrays total). Slides were scanned with a ScanArray Express microarray scanner (Perkin Elmer) at 10 μm resolution and quantified using ScanArray Express software. Resulting data were normalized by total intensity and median spot intensities were identified using MIDAS (v. 2.22) software.

Project description:Microarray analysis was used to identify the fludioxonil-responsive genes dependent on SskA, SrrA, HogA, and AtfA in the filamentous fungus Aspergillus nidulans. In order to identify such genes, we conducted the several types of experiment. One was a comparison between wild type treated with fludioxonil and without the treatment (Exp.1). Others were comparison between wild type treated with fludioxonil and each mutant (sskA, Exp.2; srrA, Exp.3; hogA, Exp.4; atfA, Exp.5) treated with fludioxonil. Compared the result of Exp.1 with that of other experiments, we could identify the genes whose expression was induced or repressed in response to fludioxonil in a manner dependent on SskA, SrrA, HogA, or AtfA. KEY WORD; Aspergillus nidulans, fludioxonil, SskA, SrrA, HogA, AtfA Conidia of wild type or each mutant were cultured at 37C in 100ml CD medium containing 2% glucose for 18h and treated with fludioxonil (final concentration; 10 ug/ml) or DMSO (as a solvent control) for 15 min. The mycelia were harvested and frozen in liquid nitrogen, ground to powder, and used for RNA preparation. mRNA was purified and used for hybridization experiments. A total of 2 hybridizations were performed for each microarray experiment described in the summary. The following replicates were carried out: 1. In-slide replicates were carried out for each analysis. 2. Dye swap replicates were carried out for each experiment. The slides were scanned with an Axon GenePix 4000B scanner (Molecular Devices). The resulting TIFF images were imported into GenePix Pro and fluorescent intensity of spots were calculated for each of the Cy3 and Cy5 channels. Global normalization was applied to all analyses. Following normalization, spots whose Cy3 or Cy5 intensity was less than 0 were removed from the data set (the exceptional case was that intensity of the other channel was more than 100). The dye-swap replicates and in-slide replicates were subjected to all analyses. Finally, gene expression ratios (test/reference) were calculated for each replicates. Gene expression was considered to be significantly higher or lower whenever the spot intensity changed by at least 3-fold in all four replicates for each experiment.

Dataset Information

Functional redundancy of iron acquisition systems is required for Proteus mirabilis pathogenesis during UTI

Publications

Proteobactin and a yersiniabactin-related siderophore mediate iron acquisition in Proteus mirabilis.

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