The RagA and RagB proteins of Porphyromonas gingivalis

Bacterial Protein Signatures Identified in Porphyromonas gingivalis Containing-Autophagic Vacuoles Reveal Evolutionary History Between Oral Red/Orange Complex Bacteria and Gut Resident Bacteria

Oral bacterial species have evolved in humans to enable the colonization of a diversity of commensals and opportunistic pathogens like Porphyromonas gingivalis . Due to the communalistic survival mechanism shared amongst oral bacteria and gut bacteria, these bacteria have likely evolved together to establish in the human oral cavity and transfer genetic information. Our liquid-chromatography with tandem-mass-spectrometry (LC-MS-MS) analysis has revealed protein signatures, Elongation Factor Tu, RagB/SusD nutrient uptake outer membrane protein and DnaK, specifically from P. gingivalis -containing autophagic vacuoles isolated from the infected primary gingival epithelial cells. Interestingly, our Mass-Spectrometry analysis reported similar proteins from closely related oral bacteria, Tannerella forsythia and Prevotella intermedia . In our phylogenetic study of these key protein signatures, we have established that pathogenic oral bacteria share extensive relatedness to each other and gut resident bacteria. We have shown that virulence factors, Elongation Factor Tu and DnaK, there are several structural similarities and conservation with proteins from pathogenic oral bacteria. We have also shown that the RagB/SusD nutrient uptake These findings may highlight the shared virulence mechanisms not only amongst oral bacterial pathogens but gut bacteria and their evolution in the human host.

Tobacco-enhanced biofilm formation by Porphyromonas gingivalis and other oral microbes

Microbial biofilms promote pathogenesis by disguising antigens, facilitating immune evasion, providing protection against antibiotics and other antimicrobials and, generally, fostering survival and persistence. Environmental fluxes are known to influence biofilm formation and composition, with recent data suggesting that tobacco and tobacco-derived stimuli are particularly important mediators of biofilm initiation and development in vitro and determinants of polymicrobial communities in vivo. The evidence for tobacco-augmented biofilm formation by oral bacteria, tobacco-induced oral dysbiosis, tobacco-resistance strategies, and bacterial physiology is summarized herein. A general overview is provided alongside specific insights gained through studies of the model and archetypal, anaerobic, Gram-negative oral pathobiont, Porphyromonas gingivalis.

Prevalence and Phylogenetic Analysis of Lipoprotein-Gene ragB-1 of Porphyromonas gingivalis-A Pilot Study

Porphyromonas gingivalis (P.g.) is a key pathogen involved in periodontal diseases. The aim of this study was to investigate the prevalence and phylogenetic origin of the lipoprotein-gene ragB in its most virulent variant, ragB-1 (co-transcribed with ragA-1 as locus rag-1), in different P.g. strains collected worldwide. A total of 138 P.g. strains were analyzed for the presence of ragB-1 by pooled analysis and subsequently individual PCRs. Sequencing a core fragment of ragB-1 of the individual strains made it possible to carry out a phylogenetic classification using sequence alignment. In total, 22 of the 138 P.g. strains tested positive for ragB-1, corresponding to a prevalence of 16%. The fragment investigated was highly conserved, with variations in the base sequence detected in only three strains (OMI 1072, OMI 1081, and OMI 1074). In two strains, namely OMI 1072 (original name: I-433) and OMI 1081 (original name: I-372), which originate from monkeys, two amino-acid alterations were apparent. Since ragB-1 has also been found in animal strains, it may be concluded that rag-1 was transferred from animals to humans and that this originally virulent variant was weakened by mutations over time so that new, less virulent, adapted commensal versions of rag (rag-2, -3, and -4), with P.g. as the host, evolved.

Anti-biofilm effect of salivary histatin 5 on Porphyromonas gingivalis

This study aimed to investigate the effects of salivary histatin 5 (Hst5) on Porphyromonas gingivalis (P. gingivalis) biofilms in vitro and in vivo and the possible mechanisms. In in vitro experiments, P. gingivalis biomass was determined by crystal violet staining. Polymerase chain reaction, scanning electron microscopy, and confocal laser scanning microscopy were used to determine the Hst5 concentration. A search for potential targets was performed using transcriptomic and proteomic analyses. In vivo experimental periodontitis was established in rats to evaluate the effects of Hst5 on periodontal tissues. Experimental results showed that 25 µg/mL Hst5 effectively inhibited biofilm formation, and increased concentrations of Hst5 increased the inhibitive effect. Hst5 might bind to the outer membrane protein RagAB. A combination of transcriptomic and proteomic analyses revealed that Hst5 could regulate membrane function and metabolic processes in P. gingivalis, in which RpoD and FeoB proteins were involved. In the rat periodontitis model, alveolar bone resorption and inflammation levels in periodontal tissues were reduced by 100 µg/mL Hst5. This study showed that 25 µg/mL Hst5 inhibited P. gingivalis biofilm formation in vitro by changing membrane function and metabolic process, and RpoD and FeoB proteins might play important roles in this process. Moreover, 100 µg/mL Hst5 inhibited periodontal inflammation and alveolar bone loss in rat periodontitis via its antibacterial and anti-inflammatory effects. KEY POINTS: • Anti-biofilm activity of histatin 5 on Porphyromonas gingivalis was investigated. • Histatin 5 inhibited Porphyromonas gingivalis biofilm formation. • Histatin 5 showed inhibitory effects on the occurrence of rat periodontitis.

"Medicine food homology" plants promote periodontal health: antimicrobial, anti-inflammatory, and inhibition of bone resorption

"Medicine food homology" (MFH) is a term with a lengthy history. It refers to the fact that a lot of traditional natural products have both culinary and therapeutic benefits. The antibacterial, anti-inflammatory and anticancer effects of MFH plants and their secondary metabolites have been confirmed by numerous research. A bacterially generated inflammatory illness with a complicated pathophysiology, periodontitis causes the loss of the teeth's supporting tissues. Several MFH plants have recently been shown to have the ability to prevent and treat periodontitis, which is exhibited by blocking the disease's pathogens and the virulence factors that go along with them, lowering the host's inflammatory reactions and halting the loss of alveolar bone. To give a theoretical foundation for the creation of functional foods, oral care products and adjuvant therapies, this review has especially explored the potential medicinal benefit of MFH plants and their secondary metabolites in the prevention and treatment of periodontitis.

Evolutionary Conserved Short Linear Motifs Provide Insights into the Cellular Response to Stress

Short linear motifs (SLiMs) are evolutionarily conserved functional modules of proteins composed of 3 to 10 residues and involved in multiple cellular functions. Here, we performed a search for SLiMs that exert sequence similarity to two segments of alpha-fetoprotein (AFP), a major mammalian embryonic and cancer-associated protein. Biological activities of the peptides, LDSYQCT (AFP_14-20) and EMTPVNPGV (GIP-9), have been previously confirmed under in vitro and in vivo conditions. In our study, we retrieved a vast array of proteins that contain SLiMs of interest from both prokaryotic and eukaryotic species, including viruses, bacteria, archaea, invertebrates, and vertebrates. Comprehensive Gene Ontology enrichment analysis showed that proteins from multiple functional classes, including enzymes, transcription factors, as well as those involved in signaling, cell cycle, and quality control, and ribosomal proteins were implicated in cellular adaptation to environmental stress conditions. These include response to oxidative and metabolic stress, hypoxia, DNA and RNA damage, protein degradation, as well as antimicrobial, antiviral, and immune response. Thus, our data enabled insights into the common functions of SLiMs evolutionary conserved across all taxonomic categories. These SLiMs can serve as important players in cellular adaptation to stress, which is crucial for cell functioning.

[Porphyromonas gingivalis HmuY and Its Possible Effect on the Pathogenesis of Periodontitis]

Periodontitis, one of the most common inflammatory oral diseases in human beings, threatens the health of teeth and mouth and is closely associated with the development of many systemic diseases. Existing research about the pathogenesis of periodontitis mainly focuses on the oral microbial homeostasis and its complex interaction with the immune system. Among all the oral microorganisms, Porphyromonas gingivalis ( P. gingivalis) is considered to be the main pathogen causing chronic periodontitis. Recent studies have shown that P. gingivalis poesseses HmuY, a special heme binding protein, which binds with heme to provide essential nutrition for P. gingivalis and activates the host immune system. Therefore, HmuY plays an important role in the growth, proliferation, invasion, and pathogenesis of P. gingivalis and is a potential virulence factor of the bacteria. Existing studies on HmuY are limited to the host immune response that HmuY triggers, and there are still no conclusive findings on whether HmuY participates in the pathogenesis of periodontitis through other ways, such as influencing periodontal bone metabolism. Herein, we reviewed the latest research findings on the biological characteristics and physiological functions of HmuY and its relationship with chronic periodontitis, so as to provide new ideas for in-depth research and further explorations into the pathogenesis of chronic periodontitis.