ABSTRACT Streptococcus mutans normally colonizes dental biofilms and is regularly exposed to continual cycles of acidic pH during ingestion fermentable dietary carbohydrates. The ability S. survive at low an important virulence factor in the pathogenesis caries. Despite a few studies acid adaptation mechanism this organism, little work has focused on tolerance growing high-cell-density biofilms. It unknown whether biofilm growth mode or high cell density affects by . This study was initiated...

Biofilm biology has become an expanding field of research in human, industrial and environmental ecosystems. The knowledge accumulated suggests that organisms growing biofilms develop properties different to those dwelling the planktonic state. On surveying endodontic literature it is obvious this realization fact afford resident microorganisms protection/resistance against harmful exogeneous influences including anti‐microbial agents, rather new endodontology. Hence, conditions under which...

The abilities of Streptococcus mutans to form biofilms and survive acidic pH are regarded as two important virulence determinants in the pathogenesis dental caries. Environmental stimuli thought regulate expression several genes associated with factors through activity two-component signal transduction systems. Yet, little is known involvement these systems physiology pathogenicity S. mutans. In this study, we describe a regulatory system its biofilm formation acid resistance By searching...

Using 21 species of oral bacteria, representing six acidogenic genera, we undertook to determine whether the pH‐limiting exponential growth is related ability organisms generate an acid‐tolerance response that results in enhanced survival at low pH. The lower pH limit varied by more than two units with Neisseria A182 6.34; Lacto‐bacillus casel RB1014 stopped 3.81, Actinomyces, Enter ococcus, Prevotella and Streptococcus falling between these limits. working hypothesis was higher limits for...

Streptococcus mutans, a major causal agent of dental caries, functions in nature as component biofilm on teeth (dental plaque) and yet very little information is available the physiology organism such surface-associated communities. As consequence, we undertook to examine synthesis proteins by planktonic cells growing chemostat at pH 7.5 dilution rate 0.1 h−1 (mean generation time=7 h). Cells were incubated with 14C-labelled amino acids, extracted separated two-dimensional electrophoresis...

Streptococcus mutans, a member of the dental plaque community, has been shown to be involved in carious process. Cells S. mutans induce an acid tolerance response (ATR) when exposed sublethal pH values that enhances their survival at lower pH. Mature biofilm cells are more resistant stress than planktonic cells. We were interested studying and ATR-inducing ability newly adhered mutans. All experiments carried out using flow-cell systems, with tested by exposing 3-h 3.0 for 2 h counting...

Abstract Aim To determine whether bacteria isolated from infected root canals survive alkaline shifts better in biofilms than planktonic cultures. Methodology Clinical isolates of Enterococcus faecalis , Lactobacillus paracasei Olsenella uli Streptococcus anginosus S. gordonii oralis and Fusobacterium nucleatum biofilm cultures were stressed at pH 10.5 for 4 h, cell viability determined using the fluorescent staining LIVE/DEAD Bac Light bacterial kit. In addition, proteins released into...

The VicRK two-component signaling system modulates biofilm formation, genetic competence, and stress tolerance in Streptococcus mutans. We show here that the bacteriocin production cell viability, part by direct modulation of competence-stimulating peptide (CSP) S. Global transcriptome real-time transcriptional analysis VicK-deficient mutant (SmuvicK) revealed significant several bacteriocin-related loci, including nlmAB, nlmC, nlmD (P < 0.001), suggesting a role for producing mutacins IV,...

Supragingival dental plaque samples were collected from 40 Swedish adolescents, including 20 with caries lesions (CAR) and caries-free (CF). Fresh subjected to an ex vivo acid tolerance (AT) test where the proportion of bacteria resistant shock was evaluated through confocal microscopy live/dead staining, metabolites produced quantified by 1 H Nuclear Magnetic Resonance ( NMR). In addition, DNA extracted 16S rRNA gene sequenced Illumina sequencing, in order characterize bacterial composition...

The authors have previously demonstrated that Streptococcus mutans shows an exponential-phase acid-tolerance response following acid shock from pH 7.5 to 5.5 enhances survival at 3.0. In this study the of S. H7 was compared with responses generated by salt, heat, oxidation and starvation. Prior induction did not cross-protect cells a subsequent challenge other stresses; however, prior adaptation stresses, except heat (42 degrees C), protected during 3.5. Starvation fivefold dilution basal...

The degradation of complex substrates, like salivary mucins, requires an arsenal glycosidases and proteases to sequentially degrade the oligosaccharides polypeptide backbone. mucin MUC5B is a oligomeric glycoprotein, heterogeneous in molecular mass (14-40 x 10(6) Da), with diverse repertoire oligosaccharides, differing composition charge. aim this study was investigate whether proteolytic backbone could be identified if cooperation dental biofilm bacteria required. Cooperative...

Abstract Background The soft tissue around dental implants forms a barrier between the oral environment and peri-implant bone crucial factor for long-term success of therapy is development good abutment/soft-tissue seal. Sol-gel derived nanoporous TiO 2 coatings have been shown to enhance soft-tissue attachment but their effect on adhesion biofilm formation by bacteria unknown. Methods We investigated how properties surfaces that may be used abutments: turned titanium, sol-gel coated...

Summary Many studies to identify surfaces that enhance the incorporation of dental implants into bone and soft‐tissue have been undertaken previously. However, succeed in clinical situation, an implant surface must not support development microbial biofilms with a pathogenic potential. As first step investigating this, we used two‐species three‐species biofilm models 16S ribosomal RNA fluorescence situ hybridization confocal laser scanning microscopy examine effect characteristics on...

Hydrogen sulfide (H2S) is a toxic foul-smelling gas produced by subgingival biofilms in patients with periodontal disease and suggested to be part of the pathogenesis disease. We studied H2S-producing protein expression bacterial strains associated Further, we examined effect cysteine-rich growth environment on synthesis intracellular enzymes F. nucleatum polymorphum ATCC 10953. The proteins were subjected one-dimensional (1DE) two-dimensional (2DE) gel electrophoresis An in-gel activity...

A key element for long-term success of dental implants is integration the implant surface with surrounding host tissues. Modification titanium surfaces can enhance osteoblast activity but their effects on soft-tissue cells are unclear. Adherence human keratinocytes and gingival fibroblasts to control commercially pure (CpTi) two prepared by anodic oxidation was therefore investigated. Since abutments exposed a bacteria-rich environment in vivo, effect oral bacteria keratinocyte adhesion also...

Formative assessment with emphasis on feedback has been linked to developmental purposes of assessment, whilst summative is assumed focus judgemental and quality assurance purposes. This dichotomy questioned but designs blend formative assessments in constructive ways are rare health care education.We have designed an model blending assessments. In the at end a course, students' responses real-life scenarios questions demanding relational level understanding were assessed three levels...

The intent of this study was to compare the inherent acid tolerance bacteria in samples dental plaque from tooth sites subjects with and without initial caries. Plaque collected approximal surfaces showing early enamel caries healthy same subjects, as well caries-free individuals. In addition plating on blood agar, were plated directly non-selective solid agar medium buffered pH 7.0, 6.0, 5.5, 5.0, 4.5 4.0 avoid any loss adaptation during primary isolation bacteria. results showed that...

A new undergraduate dental curriculum was introduced in Malmö 1990 which is based on problem-based learning (PBL). The principles of PBL are strongly influenced by evidence from cognitive psychology and they form the educational strategy throughout whole curriculum. Two further essential underpin curriculum: a holistic attitude to patient care, promotion oral health. Basic sciences clinical dentistry integrated within structure conditions prevalent community. Students encouraged build their...

Plasminogen binding by bacteria is a virulence factor important for the entry and dissemination of in body. A wide variety bind plasminogen, including both organisms causing disease components normal oral flora. The purpose this study was to examine characteristics plasminogen six clinical isolates streptococci from dental plaque inflammatory lesions. All strains bound with approximately same affinity, specific lysine-dependent as evidenced its inhibition epsilon-aminocaproic acid. test were...

Introduction: Model systems with oral bacteria from dental plaque have demonstrated that the utilization of complex glycoproteins as a food source cannot be undertaken by single species but requires concerted degradation multi‐species consortium, each member contributing one or few hydrolytic enzymes. Unlike previous studies, aim present investigation was to explore ability fresh degrade salivary mucin, MUC5B, isolated methods designed retain intact natural polymeric structure and...

The ability of oral bacteria to enter a non-growing state is believed be an important mechanism for survival in the starved micro-environments cavity. In this study, we examined reactivation nutrient-deprived cells two biofilms, Streptococcus anginosus and Lactobacillus salivarius. Non-growing were generated by incubation 10 mM potassium phosphate buffer 24 h results compared those planktonic cultures. When both types shifted from rich, peptone–yeast extract–glucose (PYG) medium h,...

Non-typeable Haemophilus influenzae (NTHi) is a common pathogen associated with diseases such as acute otitis media or exacerbations in patients chronic obstructive pulmonary disease. The biofilm-forming capability substantially contributes to the persistence of NTHi. However, regulation biofilm formation not completely understood. Quorum sensing regulated by autoinducer-2 produced luxS until now only described regulatory mechanism. In this study, we show that two-component signalling system...