Streptococcus gordonii is a commensal Gram‐positive bacterium that acts as an opportunistic pathogen that can cause apical periodontitis, endocarditis, and pneumonia. Biofilm formation of bacteria is important for the initiation and progression of such diseases. Although lipoproteins play key roles in physiological functions, the role of lipoproteins of S. gordonii in its biofilm formation has not

Porphyromonas gingivalis, a pathogen of chronic periodontitis, is an asaccharolytic microorganism that solely utilizes nutritional amino acids as its energy source and cellular constituents. The bacterium is considered to incorporate proteinaceous nutrients mainly as dipeptides, thus exopeptidases that produce dipeptides from polypeptides are critical for survival and proliferation. We present here

S. mutans, a major etiological agent of human dental caries, produces membrane vesicles (MVs) that contain protein and extracellular DNA. In this study, functional genomics, along with in vitro biofilm models, was used to identify factors that regulate MV biogenesis. Our results showed that when added to growth medium, MVs significantly enhanced biofilm formation by S. mutans, especially during growth

Porphyromonas gingivalis is a gram‐negative anaerobic bacterium and an etiologic agent of adult periodontitis. By inducing a dysbiotic state within the host microbiota it contributes to a chronic inflammatory environment in the oral cavity. Under some circumstances, the oral bacteria may gain access to systemic circulation. While the most widely recognized function of platelets is to reduce hemorrhage

Enterococci are Gram‐positive, opportunistic pathogens that reside throughout the gastrointestinal tracts of most terrestrial organisms. Enterococci are resistant to many antibiotics, which makes enterococcal infections difficult to treat. Enterococci are also particularly hardy bacteria that can tolerate a variety of environmental stressors. Understanding how enterococci sense and respond to the extracellular

Porphyromonas gingivalis expresses a limited number of two‐component systems, including RprY, an orphan response regulator which lacks a cognate sensor kinase. In this study, we examined cross‐phosphorylation of RprY on tyrosine residues and its importance for RprY function. We show that RprY reacts with phosphotyrosine antibodies, and found that the tyrosine (Y) residue at position 41 is predicted

Streptococcus mutans is a major etiologic agent of dental caries, which is the most common chronic infectious disease worldwide. S. mutans is particularly adept at causing caries due to its exceptional capacity to form biofilms and its ability to survive acidic conditions that arrest acid production and growth in many more benign members of the oral microbiota. Two mechanisms utilized by S. mutans

Lactobacillus rhamnosus is an important lactic acid bacterium that is predominantly used as a probiotic supplement. This bacterium secretes immunomodulatory and antibacterial peptides that are necessary for the probiotic trait. This organism also occupies diverse ecological niches, such as gastrointestinal tracts and the oral cavity. Several studies have shown that L. rhamnosus is prone to spontaneous

The oral pathogen, Aggregatibacter actinomycetemcomitans, produces a number of virulence factors, including a leukotoxin (LtxA), which specifically kills human white blood cells, to provide a colonization advantage to the bacterium. Strains of A. actinomycetemcomitans that produce more LtxA have been more closely linked to disease, indicating that this toxin plays a key role in pathogenesis of the

The use of next generation sequencing and bioinformatics has revealed the complexity and richness of the human oral microbiota. While some species are well known for their periodontal pathogenicity, the molecular‐based approaches for bacterial identification have raised awareness about new putative periodontal pathogens. Although they are found increased in case of periodontitis, there is currently

Smokers are more likely than non‐smokers to harbour Porphyromonas gingivalis, they are more susceptible to destructive periodontal disease and smokers may, ultimately, benefit from tobacco‐specific preventive and treatment strategies. A Mariner transposon insertion library for P. gingivalis ATCC 33277 was exploited to define 256 genes as essential for P. gingivalis survival in a tobacco‐rich environment

Filifactor alocis, a gram‐positive, obligate anaerobic rod, is an emerging periodontal pathogen that is frequently isolated from patients with periodontitis, peri‐implantitis, and apical periodontitis. Recent studies have shown that extracellular vesicles (EVs) from gram‐negative periodontal pathogens, so‐called outer membrane vesicles (OMVs), harbor various effector molecules responsible for inducing

Cnm, a collagen- and laminin-binding protein present in a subset of Streptococcus mutans strains, mediates binding to extracellular matrices (ECM), intracellular invasion and virulence in the Galleria mellonella model. Antibodies raised against Cnm were used to confirm expression and the cell surface localization of Cnm in the highly invasive OMZ175 strain. Sequence analysis identified two additional

Pheromone‐mediated conjugative transfer of enterococcal plasmids can contribute to the dissemination of genes involved in antibiotic resistance, fitness, and virulence among co‐residents of mixed microbial communities. We have previously shown that intergeneric signaling by the Streptococcus gordonii strain Challis heptapeptide s.g.cAM373 (SVFILAA) induces an aggregation substance‐mediated mating response

Porphyromonas gingivalis, a keystone pathogen in periodontitis, secretes an array of virulence factors including gingipains via the type IX secretion system (T9SS). Inactivation of any component of the T9SS leads to the accumulation of secreted proteins in unprocessed and, in the case of progingipains, inactive forms in the periplasm. To cast light on the paradox that active gingipains are essential

Oral epithelial cells (OEC) represent the first site of host interaction with viruses that infect the body through the oral route; however, their innate antiviral defense mechanisms yet to be defined. Previous studies have determined that OEC express pathogen‐, damage‐, or danger‐associated molecular patterns (PAMPs or DAMPs), but their expression of key antiviral innate immune mediators, including

Interleukin‐24 is a pleiotropic immunoregulatory cytokine and a member of the IL‐20R subfamily of the IL‐10 family. The aim of this study was to investigate the regulation of IL‐24 in the human oral keratinocyte cell line HOK‐16B following infection with Tannerella forsythia, a major periodontal pathogen. T. forsythia induced the expression of IL‐24 mRNA and the secretion of glycosylated IL‐24 in HOK‐16B

The development of the oral biofilm requires a complex series of interactions between host tissues and the colonizing bacteria as well as numerous interspecies interactions between the organisms themselves. Disruption of normal host–microbe homoeostasis in the oral cavity can lead to a dysbiotic microbial community that contributes to caries or periodontal disease. A variety of approaches have been

Sortase A contributes to adhesion and biofilm formation of Streptococcus mutans by anchoring surface proteins like P1 onto the cell wall, and few other functional characterization has been annotated to this protein and its coding gene srtA. In this study we investigated that whether srtA deletion would affect S. mutans virulence determinants in addition to adhesion and further explored whether these

Studies have been conducted on the pathogenicity of periodontopathogens in cultures of endothelial cells on two‐dimensional (2D) polystyrene surfaces, where the monolayer formed is not exposed to proteins of the subendothelial matrix. In this work, we developed a culture system by seeding human coronary artery endothelial cells (HCAECs) onto three‐dimensional (3D) scaffolds of collagen type I, a subendothelial

Bacterial cell division is initiated by tubulin homologue FtsZ that assembles into a ring structure at mid‐cell to facilitate cytokinesis. EzrA has been identified to be implicated in FtsZ‐ring dynamics and cell wall biosynthesis during cell division of Bacillus subtilis and Staphylococcus aureus, the model rod and cocci. However, its role in pathogenic streptococci remains largely unknown. Here, the

Lactobacillus rhamnosus is a lactic acid bacterium that survives diverse ecological niches, including the human oral cavity and gastrointestinal tract. L. rhamnosus is an acidogenic bacterium that produces copious amounts of lactic acid. The organism is also considered as aciduric, since it can survive prolonged exposure to an acidic environment. For a probiotic bacterium such as L. rhamnosus, it is

A comparative proteomic analysis was utilized to evaluate similarities and differences in membrane samples derived from the cariogenic bacterium Streptococcus mutans, including the wild‐type strain and four mutants devoid of protein translocation machinery components, specifically ∆ffh, ∆yidC1, ∆yidC2, or ∆ffh/yidC1. The purpose of this work was to determine the extent to which the encoded proteins

Porphyromonas gingivalis has been strongly associated with chronic periodontitis, which affects tooth‐supporting tissues. This Gram‐negative anaerobic bacterium produces a repertoire of virulence factors that modulate tissue destruction directly or indirectly by the induction of inflammatory processes. The aim of this study was to investigate the effects of resveratrol, a major polyphenol found in

Although, a large proportion of pathogenic bacteria gets eliminated from hosts after antibiotic treatment, a fraction of population confronts against such effects and undergoes growth arrest to form persisters. Persistence in bacteria is a dormant physiological state where cells escape the effects of antimicrobials as well as other host immune defences without any genetic mutations. The state of dormancy

Streptococcus mutans is a causative organism of dental caries and has been reported to be associated with the development of cardiovascular disease (CVD). Previous studies have demonstrated that S. mutans invades human aortic endothelial cells (HAECs) and HAECs invaded by S. mutans produce higher levels of CVD–related cytokines than non‐invaded HAECs. DMBT1 (deleted in malignant brain tumors 1), also

Volatile sulfur compounds (VSCs) such as hydrogen sulfide (H2S) and methyl mercaptan (CH3SH) are the main components of oral malodor, and are produced as the end products of the proteolytic processes of oral microorganisms. The main pathway of proteolysis is the metabolism of sulfur‐containing amino acids by gram‐negative anaerobic bacteria. Gram‐positive bacteria may promote VSC production by gram‐negative