As a major etiological agent of human dental caries,

ABSTRACT The stringent response is a global bacterial to stress that mediated by accumulation of the alarmone (p)ppGpp. In this study, treatment with mupirocin was shown induce high levels (p)ppGpp production in Enterococcus faecalis , indicating nosocomial pathogen can mount classic response. addition, found accumulate cells subjected heat shock, alkaline and inhibitory concentrations vancomycin. Sequence analysis E. genome indicated synthesis catalyzed bifunctional synthetase/hydrolase...

Streptococcus mutans is considered the primary etiologic agent of dental caries, a global health problem that affects 60 to 90% population, and leading causative infective endocarditis. It can be divided into four different serotypes (c, e, f, k), with serotype c strains being most common in oral cavity. In this study, we demonstrate addition OMZ175 B14, three other (NCTC11060, LM7, OM50E) less prevalent e f are able invade human coronary artery endothelial cells (HCAEC). Invasive were also...

Summary The current dogma implicating RelA as the sole enzyme controlling (p)ppGpp production and degradation in Gram‐positive bacteria does not apply to Streptococcus mutans . We have now identified characterized two genes, designated relP relQ , encoding novel enzymes that are directly involved synthesis. Additionally, is co‐transcribed with a two‐component signal transduction system (TCS). Analysis of synthetic capacity various mutants behaviour strains lacking combinations synthetase...

The combination of sucrose and starch in the presence surface-adsorbed salivary α-amylase bacterial glucosyltransferases increase formation a structurally metabolically distinctive biofilm by Streptococcus mutans. This host-pathogen-diet interaction may modulate pathogenic biofilms related to dental caries disease. We conducted comprehensive study further investigate influence dietary carbohydrates on S. mutans-transcriptome at distinct stages development using whole genomic profiling with...

ABSTRACT The stringent response (SR), mediated by the alarmone (p)ppGpp, is a conserved bacterial adaptation system controlling broad metabolic alterations necessary for survival under adverse conditions. In Enterococcus faecalis , production of (p)ppGpp controlled bifunctional protein RSH (for “Rel SpoT homologue”; also known as RelA) and monofunctional synthetase RelQ. Previous characterization E. strains lacking rsh relQ or both revealed that responsible activation SR in negatively impact...

The bacterial stringent response (SR) is a conserved stress tolerance mechanism that orchestrates physiological alterations to enhance cell survival. This mediated by the intracellular accumulation of alarmones pppGpp and ppGpp, collectively called (p)ppGpp. In Enterococcus faecalis, (p)ppGpp metabolism carried out bifunctional synthetase/hydrolase E. faecalis Rel (RelEf) small alarmone synthetase (SAS) RelQEf. Although main enzyme responsible for SR activation in Firmicutes, there emerging...

Streptococcus mutans is a biofilm-forming bacterium that adapted to tolerate rapid and dramatic fluctuations in nutrient availability, carbohydrate source, pH its natural environment, the human oral cavity. Dissecting pathways used form stable biofilms environmental stress central understanding virulence of this organism. Here, we investigated role S. relA gene, which codes for guanosine tetraphosphate pentaphosphate [(p)ppGpp] synthetase/hydrolase, biofilm formation acid tolerance. Two...

Tolerance of environmental stress, especially low pH, by Streptococcus mutans is central to the virulence this organism. The Clp ATPases are implicated in tolerance of, and regulation response to, stresses virtue their protein reactivation remodeling activities capacity target misfolded proteins for degradation ClpP peptidase. purpose study was dissect role selected clp genes stress responses S. mutans, with a particular focus on acid adaptation. Homologues clpB, clpC, clpE, clpL, clpX, clpP...

ABSTRACT Previous work suggested that the underlying mechanisms by which Streptococcus mutans ClpXP protease affects virulence traits are associated with accumulation of two orthologues Spx regulator, named SpxA and SpxB. Here, a thorough characterization strains lacking spx genes (Δ spxA , Δ spxB ) revealed Spx, indeed, participates in regulation processes S. pathogenesis. The strain displayed impaired ability to grow under acidic oxidative stress conditions had diminished long-term...

High coverage, whole genome shotgun (WGS) sequencing of 57 geographically- and genetically-diverse isolates Streptococcus mutans from individuals known dental caries status was recently completed. Of the sequenced strains, fifteen isolates, were selected based primarily on differences in gene content phenotypic characteristics to affect virulence compared with reference strain UA159. A high degree variability these properties observed between a broad spectrum sensitivities low pH, oxidative...

Mutational analysis revealed that members of the Clp system, specifically ClpL chaperone and ClpXP proteolytic complex, modulate expression important virulence attributes Streptococcus mutans. Compared to its parent, DeltaclpL strain displayed an enhanced capacity form biofilms in presence sucrose, had reduced viability, was more sensitive acid killing. The DeltaclpP DeltaclpX strains several phenotypes common: slow growth, tendency aggregate culture, autolysis, ability grow under stress,...

Abstract Biofilms are comprised of bacterial-clusters (microcolonies) enmeshed in an extracellular matrix. Streptococcus mutans can produce exopolysaccharides (EPS)-matrix and assemble microcolonies with acidic microenvironments that cause tooth-decay despite the surrounding neutral-pH found oral cavity. How matrix influences pH bacterial activity locally remains unclear. Here, we simultaneously analyzed situ gene expression within intact biofilms measured impact damage to EPS-matrix. The...

Manganese (Mn) is an essential micronutrient that not readily available to pathogens during infection due active host defense mechanism known as nutritional immunity. To overcome this nutrient restriction, bacteria utilize high-affinity transporters allow them compete with metal-binding proteins. Despite the established role of Mn in bacterial pathogenesis, little about relevance pathophysiology E. faecalis. Here, we identified and characterized major acquisition systems We discovered...

Early childhood caries (ECC) recurrence occurs in approximately 40% of treated cases within one year. The association Streptococcus mutans and Candida albicans with the onset ECC is well known. Also, S. strains harboring collagen-binding proteins (Cbps) avidly bind to collagen-rich dentin are linked increased risk. Here, we investigated presence Cbp+ C. saliva dental plaque children varying statuses, their salivary microbiome. In this cross-sectional study, 143 who were caries-free (n = 73),...

Enterococcus faecalis is often coisolated with Pseudomonas aeruginosa in polymicrobial biofilm-associated infections of wounds and the urinary tract. As a defense strategy, host innately restricts iron availability at infection sites. Despite their coprevalence, interactions these two species biofilms under iron-restricted conditions remain unexplored. Here, we show that E. inhibits P. growth within when restricted. lactate dehydrogenase (

We report here that HtrA plays a role in controlling growth and competence development for genetic transformation Streptococcus mutans. Disruption of the gene resulted slow at 37 degrees C, reduced thermal tolerance 42 altered sucrose-dependent biofilm formation on polystyrene surfaces. The htrA mutant also displayed significantly ability to undergo transformation. A direct association between was demonstrated by increased expression upon exposure competence-stimulating peptide. induction...