Clinical, microbiological and immunological studies on recurrent periodontal disease

Choil, J.-I.; Nakagawa, Taneaki; Yamada, Satoru; Takazoe, I; Okuda, K

doi:10.1111/j.1600-051x.1990.tb02341.x

Cited by 51 publications

(27 citation statements)

References 56 publications

(26 reference statements)

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“…A shift in the microbial community leading to outgrowth of this anaerobe is directly linked to periodontitis, a chronic inflammatory disease that leads to destruction of the tissues supporting the gums and ultimately, exfoliation of the teeth (Choil et al, 1990;Dzink et al, 1988;Grossi et al, 1994;Lamont & Jenkinson, 2000;Moore et al, 1991). This commensal can colonize, invade and multiply within gingival epithelial cells, as well as penetrate into deeper epithelial cell layers, potentially releasing the whole organism and/or virulence factors into the bloodstream (reviewed by Yilmaz, 2008).…”

Section: Introductionmentioning

confidence: 99%

The nucleoid-associated protein HUβ affects global gene expression in Porphyromonas gingivalis

et al. 2013

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HU is a non-sequence-specific DNA-binding protein and one of the most abundant nucleoidassociated proteins in the bacterial cell. Like Escherichia coli, the genome of Porphyromonas gingivalis is predicted to encode both the HUa (PG1258) and the HUb (PG0121) subunit. We have previously reported that PG0121 encodes a non-specific DNA-binding protein and that PG0121 is co-transcribed with the K-antigen capsule synthesis operon. We also reported that deletion of PG0121 resulted in downregulation of capsule operon expression and produced a P. gingivalis strain that is phenotypically deficient in surface polysaccharide production. Here, we show through complementation experiments in an E. coli MG1655 hupAB double mutant strain that PG0121 encodes a functional HU homologue. Microarray and quantitative RT-PCR analysis were used to further investigate global transcriptional regulation by HUb using comparative expression profiling of the PG0121 (HUb) mutant strain to the parent strain, W83. Our analysis determined that expression of genes encoding proteins involved in a variety of biological functions, including iron acquisition, cell division and translation, as well as a number of predicted nucleoid associated proteins were altered in the PG0121 mutant. Phenotypic and quantitative real-time-PCR (qRT-PCR) analyses determined that under iron-limiting growth conditions, cell division and viability were defective in the PG0121 mutant. Collectively, our studies show that PG0121 does indeed encode a functional HU homologue, and HUb has global regulatory functions in P. gingivalis; it affects not only production of capsular polysaccharides but also expression of genes involved in basic functions, such as cell wall synthesis, cell division and iron uptake. INTRODUCTIONPorphyromonas gingivalis is a Gram-negative obligate anaerobe belonging to the family Bacteroidaceae that persists as a natural member of the human oral microbiota. A shift in the microbial community leading to outgrowth of this anaerobe is directly linked to periodontitis, a chronic inflammatory disease that leads to destruction of the tissues supporting the gums and ultimately, exfoliation of the teeth (Choil et al., 1990;Dzink et al., 1988;Grossi et al., 1994;Lamont & Jenkinson, 2000;Moore et al., 1991). This commensal can colonize, invade and multiply within gingival epithelial cells, as well as penetrate into deeper epithelial cell layers, potentially releasing the whole organism and/or virulence factors into the bloodstream (reviewed by Yilmaz, 2008). In addition to its ability to cause disease in the oral cavity, there are data indicating a role in systemic disease, including its ability to invade vascular endothelial cells (Dorn et al., 2000(Dorn et al., , 2002Jandik et al., 2008) and to cause aggregation of platelets (Pham et al., 2002). For many pathogenic bacteria, surface polysaccharides play a key role in immune modulation et al., 1996). HU typically acts as an accessory protein in virtually all types of nucleoprotein-mediated processes (reviewed by...

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Section: Introductionmentioning

confidence: 99%

The nucleoid-associated protein HUβ affects global gene expression in Porphyromonas gingivalis

et al. 2013

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“…P. gingivalis is a Gram-negative anaerobe that persists within the oral biofilm community. Outgrowth of this normally commensal organism is associated with severe periodontal disease, resulting in the destruction of tissues that support the gums and, ultimately, tooth loss (Choi et al, 1990;Dzink et al, 1988; Grossi et al, 1994;Lamont & Yilmaz, 2002;Moore et al, 1991). Several studies have shown that P. gingivalis can invade and multiply within gingival epithelial cells, as well as penetrate deeper epithelial cell layers, releasing the whole organism and/or virulence factors into the bloodstream (reviewed by Yilmaz, 2008).…”

Section: Introductionmentioning

confidence: 99%

A streptococcal effector protein that inhibits Porphyromonas gingivalis biofilm development

Christopher¹,

Arndt

Cugini³

et al. 2010

Microbiology

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Dental plaque formation is a developmental process involving cooperation and competition within a diverse microbial community, approximately 70 % of which is composed of an array of streptococci during the early stages of supragingival plaque formation. In this study, 79 cell-free culture supernatants from a variety of oral streptococci were screened to identify extracellular compounds that inhibit biofilm formation by the oral anaerobe Porphyromonas gingivalis strain 381. The majority of the streptococcal supernatants (61 isolates) resulted in lysis of P. gingivalis cells, and some (17 isolates) had no effect on cell viability, growth or biofilm formation. One strain, however, produced a supernatant that abolished biofilm formation without affecting growth rate. Analysis of this activity led to the discovery that a 48 kDa protein was responsible for the inhibition. Protein sequence identification and enzyme activity assays identified the effector protein as an arginine deiminase. To identify the mechanism(s) by which this protein inhibits biofilm formation, we began by examining the expression levels of genes encoding fimbrial subunits; surface structures known to be involved in biofilm development. Quantitative RT-PCR analysis revealed that exposure of P. gingivalis cells to this protein for 1 h resulted in the downregulation of genes encoding proteins that are the major subunits of two distinct types of thin, single-stranded fimbriae (fimA and mfa1). Furthermore, this downregulation occurred in the absence of arginine deiminase enzymic activity. Hence, our data indicate that P. gingivalis can sense this extracellular protein, produced by an oral streptococcus (Streptococcus intermedius), and respond by downregulating expression of cell-surface appendages required for attachment and biofilm development. INTRODUCTIONHigh cell density and microbial diversity are fundamental to the development and function of the oral biofilm (Kolenbrander et al., 2002). The close proximity of cells within the biofilm facilitates cell-cell interactions, while the diversity offers a wide variety of metabolic functions, allowing the community to acquire nutrients and persist. During plaque formation, organisms affect the activities of one another via physical associations and through the release of extracellular molecules; the effects of these interactions range from mutualistic to antagonistic (Davey & Costerton, 2006;Socransky & Haffajee, 2000). Molecules that are excreted by bacteria into the environment or directly into host cells (through either non-classical or conventional secretion pathways), affecting gene expression of another organism, are often referred to as effectors. The primary objective of this study was to identify effectors produced by oral streptococci that modulate biofilm formation by the oral anaerobe Porphyromonas gingivalis. P. gingivalis is a Gram-negative anaerobe that persists within the oral biofilm community. Outgrowth of this normally commensal organism is associated with severe periodontal disease, r...

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“…Formation of a periodontal pocket, destruction of supporting connective tissues, and loss of alveolar bone take place in the progression of this disease. Although the bacterium may be eliminated by successful therapies [9], it causes recurrent infections [5]. P. gingivalis cells are found in healthy sites [4], but significantly elevated levels of the organism are observed in periodontal lesions [5,6].…”

Section: Introductionmentioning

confidence: 99%

Iron and heme utilization inPorphyromonas gingivalis

et al. 2005

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Porphyromonas gingivalis is a Gram-negative anaerobic bacterium associated with the initiation and progression of adult periodontal disease. Iron is utilized by this pathogen in the form of heme and has been shown to play an essential role in its growth and virulence. Recently, considerable attention has been given to the characterization of various secreted and surface-associated proteins of P. gingivalis and their contribution to virulence. In particular, the properties of proteins involved in the uptake of iron and heme have been extensively studied. Unlike other Gram-negative bacteria, P. gingivalis does not produce siderophores. Instead it employs specific outer membrane receptors, proteases (particularly gingipains), and lipoproteins to acquire iron/heme. In this review, we will focus on the diverse mechanisms of iron and heme acquisition in P. gingivalis. Specific proteins involved in iron and heme capture will be described. In addition, we will discuss new genes for iron/heme utilization identified by nucleotide sequencing of the P. gingivalis W83 genome. Putative iron- and heme-responsive gene regulation in P. gingivalis will be discussed. We will also examine the significance of heme/hemoglobin acquisition for the virulence of this pathogen.

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Clinical, microbiological and immunological studies on recurrent periodontal disease

Cited by 51 publications

References 56 publications

The nucleoid-associated protein HUβ affects global gene expression in Porphyromonas gingivalis

The nucleoid-associated protein HUβ affects global gene expression in Porphyromonas gingivalis

A streptococcal effector protein that inhibits Porphyromonas gingivalis biofilm development

Iron and heme utilization inPorphyromonas gingivalis

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