Although Streptococcus mutans has been implicated as a major etiological agent of dental caries, our cross-sectional preliminary study indicated that 10% subjects with rampant caries in permanent teeth do not have detectable levels S. mutans. Our aims were to use molecular methods detect all bacterial species associated primary and determine the profiles different disease states. Plaque was collected from 39 healthy controls intact enamel white-spot lesions, dentin deep-dentin lesions each...

ABSTRACT Although substantial epidemiologic evidence links Streptococcus mutans to caries, the pathobiology of caries may involve more complex communities bacterial species. Molecular methods for identification and enumeration now make it possible precisely study microbiota associated with dental caries. The purpose this was compare bacteria found in early childhood (ECC) those caries-free children by using molecular methods. Cloning sequencing 16S ribosomal DNAs from a healthy subject ECC...

Recent investigations of the human subgingival oral flora based on ribosomal 16S cloning and sequencing have shown many bacterial species present to be novel or phylotypes. The purpose investigation was identify potential periodontal pathogens among these newly identified Species-specific primers for PCR amplification were developed detection new species. Associations with chronic periodontitis observed several phylotypes, including uncultivated clones D084 BH017 from Deferribacteres phylum,...

Dental caries in very young children may be severe, result serious infection, and require general anesthesia for treatment. results from a shift within the biofilm community specific to tooth surface, acidogenic species are responsible caries. Streptococcus mutans, most common acid producer caries, is not always present occurs as part of complex microbial community. Understanding degree which multiple provide functional redundancy resilience caries-associated communities will important...

ABSTRACT Most studies of the bacterial etiology periodontitis have used either culture-based or targeted DNA approaches, and so it is likely that pathogens remain undiscovered. The purpose this study was to use culture-independent, quantitative analysis biofilms associated with chronic periodontal health identify beneficial species. Samples from subjects controls were analyzed using ribosomal 16S cloning sequencing. Several genera, many them uncultivated, periodontitis, most numerous which...

ABSTRACT Previous studies have confirmed the association of acid producers Streptococcus mutans and Lactobacillus spp. with childhood caries, but they also suggested these microorganisms are not sufficient to explain all cases caries. In addition, health-associated bacterial community profiles well understood, including importance base production catabolism in pH homeostasis. The composition health severe caries young permanent dentition was compared using Sanger sequencing ribosomal 16S...

ABSTRACT The gingival sulcus contains a complex ecosystem that includes many uncultivated bacteria. Understanding the dynamics of this in transitions between health and disease is important advancing our understanding bacterial etiology periodontitis. objective longitudinal study was to examine stability colonization crevice explore relationship shifts microbial composition changes periodontal status using comprehensive, quantitative, culture-independent approach. Subgingival plaque samples...

ABSTRACT Periodontitis is a common, progressive disease that eventually affects the majority of population. The local destruction periodontitis believed to result from bacterial infection gingival sulcus, and several clinical studies have provided evidence implicate Porphyromonas gingivalis . If P. periodontal pathogen, it would be expected present in most subjects with rarely detected good health. However, previous studies, has not been disease, age-matched, periodontally healthy controls...

ABSTRACT Accurate quantitation of the number cells individual bacterial species in dental plaque samples is needed for understanding etiology periodontitis. Real-time PCR offers a sensitive, efficient, and reliable approach to quantitation. Using TaqMan system we were able determine both amount Porphyromonas gingivalis total present samples. species-specific primers fluorescent probe, detection DNA from serial dilutions P. was linear over large range concentrations (correlation coefficient =...

Comparing bacterial 16S rDNA sequences to GenBank and other large public databases via BLAST often provides results of little use for identification taxonomic assignment the organisms interest. The human microbiome, in particular oral includes many taxa, accurate sequence data is essential studies these communities. For this purpose, a phylogenetically curated database core CORE, was developed. goal include comprehensive minimally redundant representation bacteria that regularly reside...

Periodontitis results from the interaction between a subgingival biofilm and host immune response. Changes in composition are thought to disrupt homeostasis bacteria resulting periodontal damage. Chronic systemic inflammatory disorders have been shown affect microbiota clinical status. However, this relationship has not examined subjects with lupus erythematosus (SLE). The objective of our study was investigate influence SLE on its connection disease activity. We evaluated 52 patients...

Abstract Rheumatoid arthritis (RA) is an autoimmune disease characterized by joint inflammation. Individuals with RA have a higher risk of periodontitis and has been linked to through the production enzymes periodontal pathogens that citrullinate proteins. This linkage supported findings associated increased severity treatment can improve symptoms RA. The possible mechanism for this association dysbiosis oral microbiota triggered RA-induced systemic We examined status subjects measuring...

Abstract The human oral cavity is sterile prior to birth, and we have limited knowledge of how complex communities are assembled. To examine bacterial acquisition community assembly over the first year life, samples from a cohort nine infants their mothers were collected, composition was studied by 16S rRNA gene sequencing. Exogenous species including skin environmental bacteria present initially, but quickly replaced small, shared microbial common all adults. Subsequent ordered succession...

Methotrexate-resistant cells, which contain a 500-fold amplification of dihydrofolate reductase (DHFR) genes, were used as model system for studying the regulation DHFR gene expression during growth stimulation. We have shown that threefold increase in mRNA levels following stimulation results from corresponding production (i.e., delivery to cytoplasm) and is not result change half-life. previously showed accompanied by an relative rate transcription gene. This suggested changes are due...

The use of murine dihydrofolate reductase (dhfr) gene amplification mutants enabled us to identify important structural and functional features the dhfr promoter region. We found another transcription unit, at least 14 kilobases in size, which initiates within 130 base pairs major transcript is transcribed divergently. 5' ends both transcripts were analyzed have multiple initiation sites. divergent appear share same region; longer overlap with a different appears code for protein; an...

Abstract Background The oral microbiota is acquired very early, but the factors shaping its acquisition are not well understood. Previous studies comparing monozygotic (MZ) and dizygotic (DZ) twins have suggested that host genetics plays a role. However, all share an equal portion of their parent’s genome, so this model informative for studying parent-to-child transmission. We used novel study design allowed us to directly examine transmission by biological versus adoptive mother-child...

ABSTRACT The presence of Porphyromonas gingivalis has been shown to be a risk factor for periodontitis in adults, and Actinobacillus actinomycetemcomitans implicated as pathogen early-onset periodontitis. Both species have establish stable colonization adults. In cross-sectional studies, both A. P. detected over one-third apparently healthy children. Information on the stability with these organisms children could help elucidate natural history development For this purpose, samples...

We used methotrexate-resistant mouse cells in which dihydrofolate reductase levels are approximately 500 times normal to study the effect of growth stimulation on gene expression. As a result stimulation, relative rate protein synthesis increased threefold, reaching maximum between 25 and 30 h after stimulation. The messenger ribonucleic acid production (i.e., appearance cytoplasm) threefold was accompanied by corresponding increase steady-state level nucleus. However, nuclear not...

Summary An association between the gram‐positive anaerobe Filifactor alocis and periodontal disease has recently emerged; however, possible pathogenic mechanisms have not been investigated. In this study we examined responses of primary cultures gingival epithelial cells (GECs) to infection with F. . Secretion pro‐inflammatory cytokines interleukin‐1β, interleukin‐6 tumor necrosis factor‐α from GECs was stimulated by infection. also induced apoptosis in through pathways that involved...

Summary Many microbial phyla that are widely distributed in open environments have few or no representatives within animal‐associated microbiota. Among them, the C hloroflexi comprises taxonomically and physiologically diverse lineages adapted to a wide range of aquatic terrestrial habitats. A distinct group uncultured chloroflexi related free‐living anaerobic naerolineae inhabits mammalian gastrointestinal tract includes low‐abundance human oral bacteria appear proliferate periodontitis....

ABSTRACT To determine if there is variability in virulence among strains of Porphyromonas gingivalis human periodontitis, their distribution a group subjects with clear indicators periodontitis and healthy, age-matched control was examined. The presence heteroduplex types P. the two groups determined PCR-based assay. This assay relied on detection polymorphisms ribosomal internal spacer region (ISR). ISR fragments generated by PCR -specific primers were hybridized to from reference strains,...

The acquisition of Porphyromonas gingivalis was examined in a cross-sectional study 198 subjects from 0 to 18 years age using PCR-based assay. P. detected the oral cavities 37% and at similar frequencies among all ages. These data indicate that may be acquired first days life.

By using PCR, Actinobacillus actinomycetemcomitans strains were identified directly from plaque samples without the need to isolate or culture bacteria. DNA fragments generated by a nested, two-step PCR amplification of ribosomal spacer region between 16S and 23S rRNA genes. For first amplification, primers homologous sequences common all bacterial species used. This was followed second with specific A. actinomycetemcomitans. The amplified as few 10 cells within total population 10(8)...