Serial Analysis of Gene Expression

Marti, Jacques; Elalouf, Jean‐Marc

doi:10.1002/3527600906.mcb.200500029

Cited by 1 publication

(1 citation statement)

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“…Metabolome analysis was done using the KEGG pathway modules and pathway mapping modes (http://www .genome.jp/kegg/pathway.html) (4). The KEGG expression database (40) and the NCBI Gene Expression Omnibus database (45) were used for reference and analysis.…”

Section: In Silico Analysismentioning

confidence: 99%

Nitric Oxide Stress Resistance in Porphyromonas gingivalis Is Mediated by a Putative Hydroxylamine Reductase

et al. 2012

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bPorphyromonas gingivalis, the causative agent of adult periodontitis, must maintain nitric oxide (NO) homeostasis and surmount nitric oxide stress from host immune responses or other oral bacteria to survive in the periodontal pocket. To determine the involvement of a putative hydroxylamine reductase (PG0893) and a putative nitrite reductase-related protein (PG2213) in P. gingivalis W83 NO stress resistance, genes encoding those proteins were inactivated by allelic exchange mutagenesis. The isogenic mutants P. gingivalis FLL455 (PG0893::ermF) and FLL456 (PG2213::ermF) were black pigmented and showed growth rates and gingipain and hemolytic activities similar to those of the wild-type strain. P. gingivalis FLL455 was more sensitive to NO than the wild type. Complementation of P. gingivalis FLL455 with the wild-type gene restored the level of NO sensitivity to a level similar to that of the parent strain. P. gingivalis FLL455 and FLL456 showed sensitivity to oxidative stress similar to that of the wild-type strain. DNA microarray analysis showed that PG0893 and PG2213 were upregulated 1.4-and 2-fold, respectively, in cells exposed to NO. In addition, 178 genes were upregulated and 201 genes downregulated more than 2-fold. The majority of these modulated genes were hypothetical or of unknown function. PG1181, predicted to encode a transcriptional regulator, was upregulated 76-fold. Transcriptome in silico analysis of the microarray data showed major metabolomic variations in key pathways. Collectively, these findings indicate that PG0893 and several other genes may play an important role in P. gingivalis NO stress resistance. Porphyromonas gingivalis is a Gram-negative anaerobic bacterium that is a primary etiologic agent of periodontal disease. This infection-induced disease is characterized by inflammation, which can result in host-mediated destruction of tooth-supporting tissues and structures (18). Nitric oxide (NO) is a key component of the host immune response. Oral neutrophils can constitutively secrete low concentrations of NO via the involvement of multiple NO synthases. However, with activation, these neutrophils have increased secretion of NO with antimicrobial effects. As in other host-pathogen interactions (22), P. gingivalis has been shown to trigger the production of NO in immune and nonimmune host cells by activating the expression of inducible nitric oxide synthases (9, 54) and can survive in NO concentrations ranging from 4.9 M to 19.2 M (47). Elevated NO concentrations are reported to cause vasodilatation and a decrease in platelet aggregation, which may contribute to gingival bleeding (18), and to have cytotoxic effects on surrounding host tissue that can lead to alveolar bone loss (7). NO is present in the saliva and gingival fluid of periodontitis patients (7,18,57). Further, saliva NO concentrations have been shown to increase with the severity of periodontitis (47).P. gingivalis, as an asaccharolytic microorganism, metabolizes nitrogenous compounds as a source of energy and generates a micr...

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Section: In Silico Analysismentioning

confidence: 99%