Microarray Analysis of Quorum-Sensing-Regulated Genes in<i>Porphyromonas gingivalis</i>

Yuan, Ling; Hillman, Jeffrey D.; Progulske‐Fox, Ann

doi:10.1128/iai.73.7.4146-4154.2005

Cited by 76 publications

(59 citation statements)

References 59 publications

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“…This study, along with the two previous studies based on sequence analysis (41,50), also reveals that certain bacteria such as Helicobacter pylori (39), Streptococcus mutans (55), Staphylococcus epidermidis (27), Porphyromonas gingivalis (20,67), Pseudomonas aeruginosa (14), and Bacillus subtilis (28), which have been shown to respond to AI-2, do not have either of the known types of AI-2 receptors (neither LuxP nor LsrB), and thus we expect that other receptors for AI-2 remain to be discovered. These receptors may be of entirely new classes or may be promiscuous receptors for other small molecules.…”

Section: Discussionmentioning

confidence: 99%

Identification of Functional LsrB-Like Autoinducer-2 Receptors

et al. 2009

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Although a variety of bacterial species have been reported to use the interspecies communication signal autoinducer-2 (AI-2) to regulate multiple behaviors, the molecular mechanisms of AI-2 recognition and signal transduction remain poorly understood. To date, two types of AI-2 receptors have been identified: LuxP, present in Vibrio spp., and LsrB, first identified in Salmonella enterica serovar Typhimurium. In S. Typhimurium, LsrB is the ligand binding protein of a transport system that enables the internalization of AI-2. Here, using both sequence analysis and structure prediction, we establish a set of criteria for identifying functional AI-2 receptors. We test our predictions experimentally, assaying key species for their abilities to import AI-2 in vivo, and test their LsrB orthologs for AI-2 binding in vitro. Using these experimental approaches, we were able to identify AI-2 receptors in organisms belonging to phylogenetically distinct families such as the Enterobacteriaceae, Rhizobiaceae, and Bacillaceae. Phylogenetic analysis of LsrB orthologs indicates that this pattern could result from one single origin of the functional LsrB gene in a gammaproteobacterium, suggesting possible posterior independent events of lateral gene transfer to the Alphaproteobacteria and Firmicutes. Finally, we used mutagenesis to show that two AI-2-interacting residues are essential for the AI-2 binding ability. These two residues are conserved in the binding sites of all the functional AI-2 binding proteins but not in the non-AI-2-binding orthologs. Together, these results strongly support our ability to identify functional LsrBtype AI-2 receptors, an important step in investigations of this interspecies signal.Autoinducer-2 (AI-2) is a small molecule produced and secreted by a large number of bacterial species belonging to very widespread branches within the kingdom Bacteria (15, 46, 64). AI-2 or its synthase, LuxS, has been implicated in the regulation of many bacterial behaviors including biofilm formation, virulence, competence, and the production of secondary metabolites like antibiotics (17,60,64). While in some cases, AI-2 is clearly acting through a canonical quorum-sensing mechanism (61), in others a role in central metabolism has been proposed (62). One of the obstacles to an understanding of the function of AI-2 in any given species is a lack of knowledge of the molecular mechanisms of AI-2 recognition, signal transduction, and/or processing.Undoubtedly, one of the major difficulties in identifying AI-2 receptors is the complexity of the chemistry of this signal molecule. The product of the reaction catalyzed by LuxS is 4,5-dihydroxy-2,3-pentadione (DPD), which, in solution, spontaneously rearranges into a variety of chemically distinct forms collectively called AI-2 (31, 46). We have shown that these forms are in equilibrium and can thus interconvert and that the availability of the different forms of AI-2 is highly dependent on the chemistry of the environment (31). Additionally, different organisms recognize dist...

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Section: Discussionmentioning

confidence: 99%

Identification of Functional LsrB-Like Autoinducer-2 Receptors

et al. 2009

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“…GroES is a 10-kDa chaperonin heat shock protein that is important in protein repair under conditions of environmental stress (33,61), while PG0778, encoding an O-sialoglycoprotease in P. gingivalis, was earlier reported to be important in gingipain biogenesis and virulence modulation through the release of sialic acid (6), which is known to be an important scavenger of reactive oxygen species and plays a role in oxidative stress resistance. However, it is unclear if a similar strategy is functional during NO stress in P. gingivalis.…”

Section: Discussionmentioning

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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“…It was shown tor-2 quorum sensinga. Tako LuxS uključen u preživljavanje Porphyromonas gingivalis regulacijom odgovara na promjene okolišnih uvjeta domaćina, poput izlaganja povišenoj temperaturi, otpornosti na djelovanje vodikova peroksida i promjenama u pH pojačanim izražavanjem stresnih proteina (35).…”

Section: Quorum Sensing and Bacterial Iron-uptakeunclassified

“…that LuxS might be involved in promoting survival of Porphyromonas gingivalis in the host by regulating its response to host-induced stresses such as high temperature exposure, resistance to hydrogen peroxide, and changes in the pH by elevated expression of stress proteins (35).…”

Section: Izjavamentioning

confidence: 99%