| characterization of hemolytic bacteria in subgingival plaque. | three-quarters of the patients with periodontal diseases surveyed in this study had one or more distinct types of hemolytic bacteria in their subgingival plaque. twelve different species of bacteria were identified, belonging to five genera (actinomyces, streptococcus, staphylococcus, prevotella, and actinobacillus). nine hemolytic isolates, consisting of four prevotella denticola strains, two actinomyces naeslundii genospecies 2 strains, and one each of p. melaninogenica, streptococcus constell ... | 1993 | 8496781 |
| microbial complexes in subgingival plaque. | it has been recognized for some time that bacterial species exist in complexes in subgingival plaque. the purpose of the present investigation was to attempt to define such communities using data from large numbers of plaque samples and different clustering and ordination techniques. subgingival plaque samples were taken from the mesial aspect of each tooth in 185 subjects (mean age 51 +/- 16 years) with (n = 160) or without (n = 25) periodontitis. the presence and levels of 40 subgingival taxa ... | 1998 | 9495612 |
| subgingival microbiota in healthy, well-maintained elder and periodontitis subjects. | this investigation compared the site prevalence of 40 subgingival species in 30 periodontally healthy (mean age 36+/-9 years), 35 elders with a well-maintained periodontium (mean age 77+/-5) and 138 adult periodontitis subjects (mean age 46+/-11). subgingival plaque samples were taken from the mesial aspect of each tooth (up to 28 samples) in the 203 subjects at baseline. the presence and levels of 40 subgingival taxa were determined in 5003 plaque samples using whole genomic dna probes and chec ... | 1998 | 9650869 |
| actinomyces naeslundii genospecies 1 and 2 express different binding specificities to n-acetyl-beta-d-galactosamine, whereas actinomyces odontolyticus expresses a different binding specificity in colonizing the human mouth. | a total of 102 strains of actinomyces were isolated from teeth, buccal mucosa and tongue in eight individuals. the isolates were characterized by multivariate statistical analyses of phenotypic characteristics, serotyping and binding to beta-linked galactosamine (n-acetyl-beta-d-galactosamine) and acidic proline-rich protein structures. based on these characteristics, isolates were classified into three major groups: (i) isolates of actinomyces naeslundii genospecies 2 were the dominant species ... | 1998 | 9872107 |
| distribution of three cariogenic bacteria in secondary carious lesions around amalgam restorations. | secondary dental caries remains an unresolved problem in dentistry and little is known of its microbial etiology. the purpose of this study was to compare the distribution of the three most suspected cariogenic groups of bacteria, mutans streptococci. actinomyces naeslundii genospecies 2 and lactobacilli, in natural secondary caries around amalgam restorations. extracted teeth with secondary caries were sectioned to obtain three samples that were randomly distributed to three different groups. e ... | 1999 | 10460959 |
| systemic doxycycline administration in the treatment of periodontal infections (ii). effect on antibiotic resistance of subgingival species. | the purpose of this investigation was to determine the proportion and prevalence of doxycycline resistant species in subgingival plaque samples taken during and after doxycycline administration. 20 subjects with adult periodontitis were randomly assigned to test (n = 10) or control groups (n = 10). saliva samples as well as subgingival plaque samples taken from the distal surface of 6 posterior teeth were collected at baseline. all subjects received full mouth srp and the test group systemic dox ... | 1999 | 10599905 |
| the effect of scaling and root planing on the clinical and microbiological parameters of periodontal diseases: 12-month results. | previously, we reported that srp resulted in a decrease in mean pocket depth and attachment level and reduced prevalence and levels of bacteroidesforsythus, porphyromonas gingivalis, and treponema denticola at 3 and 6 months post-srp in 57 subjects with adult periodontitis. 32 of the 57 subjects were monitored at 9 and 12 months. thus, the purpose of the present investigation was to evaluate the microbial and clinical effects of srp in 32 (mean age 48+/-11) subjects over a 12-month period. | 2000 | 10674959 |
| checkerboard assessments of serum antibodies to oral microbiota as surrogate markers of clinical periodontal status. | this study addresses whether checkerboard assessments of serum igg antibodies to oral bacteria may serve as surrogate markers of clinical periodontal status in epidemiologic studies. | 2001 | 11142661 |
| bacteria of asymptomatic periradicular endodontic lesions identified by dna-dna hybridization. | possible inclusion of contaminant bacteria during surgery has been problematic in studies of periradicular lesions of endodontic origin. therefore, in this study, two different surgical techniques were compared. a second problem is that some difficult to cultivate species may not be detected using bacteriological methods. molecular techniques may resolve this problem. dna-dna hybridization technology has the additional advantage that dna is not amplified. the purpose of this investigation was to ... | 2000 | 11202882 |
| subgingival microbiota of indigenous indians of central america. | to define the subgingival microbial profiles of adult subjects from a previously identified rural community of indigenous indians in guatemala, central america. | 2002 | 11895544 |
| distribution of cariogenic bacteria in carious lesions around tooth-colored restorations. | to compare the distribution of the three most suspected cariogenic groups of bacteria, mutans streptococci, actinomyces naeslundii genospecies 2, and lactobacilli in carious lesions around tooth-colored restorations. | 2002 | 12572643 |
| actinomyces spp. in supragingival plaque of ethnic chinese preschool children with and without active dental caries. | very limited molecular epidemiological data are available on the role of actinomyces spp. in the pathogenesis of caries in the primary dentition. therefore, we investigated their distribution in supragingival plaque of ethnic chinese preschool children from singapore and hong kong, either with or without active caries. plaque samples were taken from intact interproximal enamel areas using dental floss. bacterial genomic dna of each sample was extracted and variable regions of 16s ribosomal dna a ... | 2003 | 12925831 |
| genetic diversity of actinomyces naeslundii genospecies 2 in mother-child pairs. | actinomyces naeslundii genospecies 2 (gsp-2) are members of the autochthonous oral flora. chromosomal dna fingerprinting (cdf) with smai revealed extensive genetic diversity among a. naeslundii gsp-2 strains within individual mothers and children. there was a low prevalence of genotype match among a. naeslundii gsp-2 strains between all mother and child pairs. | 2003 | 14596875 |
| effect of the environment on genotypic diversity of actinomyces naeslundii and streptococcus oralis in the oral biofilm. | the genotypic diversity of actinomyces naeslundii genospecies 2 (424 isolates) and streptococcus oralis (446 isolates) strains isolated from two sound approximal sites in all subjects who were either caries active (seven subjects) or caries free (seven subjects) was investigated by using the repetitive extragenic palindromic pcr. the plaque from the caries-active subjects harbored significantly greater proportions of mutans streptococci and lactobacilli and a smaller proportion of a. naeslundii ... | 2003 | 14602602 |
| salivary actinomyces naeslundii genospecies 2 and lactobacillus casei levels predict pregnancy outcomes. | gravida's poor periodontal health is emerging as a modifiable independent risk factor for preterm delivery and low birth weight. | 2005 | 15974839 |
| effect of biofilm growth on expression of surface proteins of actinomyces naeslundii genospecies 2. | the predominant surface proteins of biofilm and planktonic actinomyces naeslundii, a primary colonizer of the tooth surface, were examined. seventy-nine proteins (the products of 52 genes) were identified in biofilm cells, and 30 of these, including adhesins, chaperones, and stress-response proteins, were significantly up-regulated relative to planktonic cells. | 2006 | 16672534 |
| evidence for recombination between a sialidase (nanh) of actinomyces naeslundii and actinomyces oris, previously named 'actinomyces naeslundii genospecies 1 and 2'. | actinomyces spp., predominant members of human oral biofilms, may use extracellular sialidase to promote adhesion, deglycosylate immunoglobulins and liberation of nutrients. partial nanh gene sequences (1,077 bp) from actinomyces oris (n=74), actinomyces naeslundii (n=30), actinomyces viscosus (n=1) and actinomyces johnsonii (n=2) which included the active-site region and the bacterial neuraminidase repeats (bnrs) were compared. the sequences were aligned and each species formed a distinct clust ... | 2008 | 18823396 |
| factors affecting human supragingival biofilm composition. ii. tooth position. | little is known regarding the factors that affect the microbial composition of supragingival biofilms. this study was designed to test the hypothesis that tooth location affects the microbial composition of supragingival plaque beyond the effect due to plaque mass as reflected by total dna probe count. | 2009 | 18973539 |
| emended description of actinomyces naeslundii and descriptions of actinomyces oris sp. nov. and actinomyces johnsonii sp. nov., previously identified as actinomyces naeslundii genospecies 1, 2 and wva 963. | actinomyces naeslundii is an important early colonizer in the oral biofilm and consists of three genospecies (1, 2 and wva 963) which cannot be readily differentiated using conventional phenotypic testing or on the basis of 16s rrna gene sequencing. we have investigated a representative collection of type and reference strains and clinical and oral isolates (n=115) and determined the partial gene sequences of six housekeeping genes (atpa, rpob, pgi, metg, glta and gyra). these sequences identifi ... | 2009 | 19244431 |
| mutualistic biofilm communities develop with porphyromonas gingivalis and initial, early, and late colonizers of enamel. | porphyromonas gingivalis is present in dental plaque as early as 4 h after tooth cleaning, but it is also associated with periodontal disease, a late-developing event in the microbial successions that characterize daily plaque development. we report here that p. gingivalis atcc 33277 is remarkable in its ability to interact with a variety of initial, early, middle, and late colonizers growing solely on saliva. integration of p. gingivalis into multispecies communities was investigated by using t ... | 2009 | 19749049 |
| central role of the early colonizer veillonella sp. in establishing multispecies biofilm communities with initial, middle, and late colonizers of enamel. | human dental biofilm communities comprise several species, which can interact cooperatively or competitively. bacterial interactions influence biofilm formation, metabolic changes, and physiological function of the community. lactic acid, a common metabolite of oral bacteria, was measured in the flow cell effluent of one-, two- and three-species communities growing on saliva as the sole nutritional source. we investigated single-species and multispecies colonization by using known initial, early ... | 2010 | 20154130 |
| the actinomyces oris type 2 fimbrial shaft fima mediates co-aggregation with oral streptococci, adherence to red blood cells and biofilm development. | summary interbacterial interactions between oral streptococci and actinomyces and their adherence to tooth surface and the associated host cells are key early events that promote development of the complex oral biofilm referred to as dental plaque. these interactions depend largely on a lectin-like activity associated with the actinomyces oris type 2 fimbria, a surface structure assembled by sortase (srtc2)-dependent polymerization of the shaft and tip fimbrillins, fima and fimb respectively. to ... | 2010 | 20545853 |
| allelic exchange in actinomyces oris with mcherry fluorescence counterselection. | described here is a method for facile generation of markerless gene deletion mutants of actinomyces oris. homologous integration of a nonreplicative vector carrying a gene exchange cassette into the bacterial chromosome was selected for by using mcherry fluorescence and resistance to kanamycin. completion of allelic replacement was counterselected for by using loss of fluorescence. | 2010 | 20601506 |
| structure of the sortase acsrtc-1 from actinomyces oris. | the crystal structure of the sortase acsrtc-1 from the oral microorganism actinomyces oris has been determined to 2.4 å resolution. acsrtc-1 is a cysteine transpeptidase that is responsible for the formation of fimbriae by the polymerization of a shaft protein. similar to other pili-associated sortases, the acsrtc-1 active site is protected by a flexible lid. the asymmetric unit contains five acsrtc-1 molecules and their catalytic cys-his-arg triads are trapped in two different conformations. it ... | 2011 | 21358052 |
| clustering of subgingival microbial species in adolescents with periodontitis. | it has become increasingly recognized that groups of microorganisms interact within the subgingival plaque of adult subjects with periodontitis. it is much less clear, however, whether the consortia of microorganisms associated with periodontitis are different in early and more advanced cases of periodontitis. to investigate this point further, subgingival plaque was collected from six sites in 87 adolescents with periodontitis and 73 controls and the samples were analyzed for the detection of 1 ... | 2011 | 21410554 |
| dual function of a tip fimbrillin of actinomyces in fimbrial assembly and receptor binding. | interaction of actinomyces oris with salivary proline-rich proteins (prps), which serve as fimbrial receptors, involves type 1 fimbriae. encoded by the gene locus fimq-fimp-srtc1, the type 1 fimbria is comprised of fimbrial shaft fimp and tip fimbrillin fimq. fimbrial polymerization requires fimbria-specific sortase srtc1 that catalyzes covalent linkage of fimbrial subunits. by using genetics, biochemical methods and electron microscopy, we provide here evidence that the tip fimbrillin fimq is i ... | 2011 | 21531799 |
| garlic allicin as a potential agent for controlling oral pathogens. | abstract garlic has been used medicinally throughout human history. allicin is considered the most therapeutic constituent of garlic. this study tested the antimicrobial activity of garlic allicin on oral pathogens associated with dental caries and periodontitis. allicin was found effective against all the tested bacteria. the broth dilution method revealed that planktonic growth of the cariogenic, gram-positive species streptococcus mutans, s. sobrinus, and actinomyces oris was inhibited by an ... | 2011 | 21548800 |
| identification of the srtc1 transcription start site and catalytically essential residues required for actinomyces orisôçât14v srtc1 activity. | in actinomyces oris t14v, sortase srtc1 mediates the assembly of type 1 fimbriae. we analyzed the effects of the conserved residues (h184, h204, f213, y236, l263, t265, c266 and r275) on the srtc1 activity by site-directed mutagenesis. we identified three essential conserved residues (h204, y236 and c266) that are critical for the assembly of type 1 fimbriae in this organism. rapid amplification of cdna ends analyses and reverse transcriptase-pcr results indicate that srtc1 was transcribed toget ... | 2011 | 21676012 |
| application of mlst and pilus gene sequence comparisons to investigate the population structures of actinomyces naeslundii and actinomyces oris. | actinomyces naeslundii and actinomyces oris are members of the oral biofilm. their identification using 16s rrna sequencing is problematic and better achieved by comparison of metg partial sequences. a. oris is more abundant and more frequently isolated than a. naeslundii. we used a multi-locus sequence typing approach to investigate the genotypic diversity of these species and assigned a. naeslundii (nôçè=ôçè37) and a. oris (nôçè=ôçè68) isolates to 32 and 68 sequence types (st), respectively. n ... | 2011 | 21738661 |
| crystallization of the fimbrial protein fimp from actinomyces oris and of a triple ile-to-met mutant engineered to facilitate selenomethionine labelling. | actinomyces oris is an oral bacterium important for the development of dental plaque. it expresses two forms of fimbriae: type 1 and type 2. fimp, which is the fimbrial protein that is polymerized into the stalk of the type 1 fimbriae, was cloned, overexpressed and crystallized. x-ray data were collected and processed to 2.2 å resolution. the crystals belonged to space group p2(1)2(1)2, with one molecule in the asymmetric unit. to facilitate structure determination using single anomalous dispers ... | 2011 | 22102028 |
| validation of a quantitative real-time pcr assay and comparison with fluorescence microscopy and selective agar plate counting for species-specific quantification of an in vitro subgingival biofilm model. | subgingival biofilms are the prime etiological factor of periodontal disease. owing to their complex polymicrobial nature, quantification of individual bacterial species within the biofilm for research and diagnostic purposes can be methodologically challenging. the aims of this study were to establish a quantitative real-time pcr (qpcr) assay to quantify the bacteria used in our 10-species in vitro 'subgingival' biofilm model and to compare the quantitative outcome with fluorescence microscopy ... | 2012 | 23278531 |
| impact of early colonizers on in vitro subgingival biofilm formation. | the aim of this study was to investigate the impact of early colonizing species on the structure and the composition of the bacterial community developing in a subgingival 10-species biofilm model system. the model included streptococcus oralis, streptococcus anginosus, actinomycesoris, fusobacterium nucleatum subsp. nucleatum, veillonella dispar, campylobacter rectus, prevotella intermedia, porphyromonas gingivalis, tannerella forsythia, and treponema denticola. based on literature, we consider ... | 2013 | 24340084 |
| serum igg antibody levels to periodontal microbiota are associated with incident alzheimer disease. | periodontitis and alzheimer disease (ad) are associated with systemic inflammation. this research studied serum igg to periodontal microbiota as possible predictors of incident ad. | 2014 | 25522313 |
| proteomic profiling of host-biofilm interactions in an oral infection model resembling the periodontal pocket. | periodontal infections cause inflammatory destruction of the tooth supporting tissues. we recently developed a dynamic, in vitro periodontal organotypic tissue model in a perfusion bioreactor system, in co-culture with an 11-species subgingival biofilm, which may recapitulate early events during the establishment of periodontal infections. this study aimed to characterize the global proteome regulations in this host-biofilm interaction model. semi-quantitative shotgun proteomics were applied for ... | 2015 | 26525412 |
| incorporation of staphylococci into titanium-grown biofilms: an in vitro "submucosal" biofilm model for peri-implantitis. | staphylococcus spp. are postulated to play a role in peri-implantitis. this study aimed to develop a "submucosal" in vitro biofilm model, by integrating two staphylococci into its composition. | 2015 | 26461083 |
| establishment of an oral infection model resembling the periodontal pocket in a perfusion bioreactor system. | periodontal infection involves a complex interplay between oral biofilms, gingival tissues and cells of the immune system in a dynamic microenvironment. a humanized in vitro model that reduces the need for experimental animal models, while recapitulating key biological events in a periodontal pocket, would constitute a technical advancement in the study of periodontal disease. the aim of this study was to use a dynamic perfusion bioreactor in order to develop a gingival epithelial-fibroblast-mon ... | 2015 | 25587671 |
| disulfide-bond-forming pathways in gram-positive bacteria. | disulfide bonds are important for the stability and function of many secreted proteins. in gram-negative bacteria, these linkages are catalyzed by thiol-disulfide oxidoreductases (dsb) in the periplasm. protein oxidation has been well studied in these organisms, but it has not fully been explored in gram-positive bacteria, which lack traditional periplasmic compartments. recent bioinformatics analyses have suggested that the high-gc-content bacteria (i.e., actinobacteria) rely on disulfide-bond- ... | 2016 | 26644434 |
| pathogenicity of exopolysaccharide-producing actinomyces oris isolated from an apical abscess lesion. | to demonstrate a capacity for producing exopolysaccharides (epss) and an ability to form biofilm on abiotic materials of actinomyces oris strain k20. | 2012 | 22900599 |
| suppuration-associated bacteria in patients with chronic and aggressive periodontitis. | suppuration (sup) on probing may be an indication of active periodontal breakdown. the aim of the present study is to analyze which subgingival species are associated with sup in patients with chronic (cp) and aggressive (agp) periodontitis. | 2013 | 23327648 |
| identification of non-streptococcal organisms from human dental plaque grown on the streptococcus-selective medium mitis-salivarius agar. | mitis-salivarius (ms) agar has been used widely in microbial epidemiological studies because oral viridans streptococci can be selectively grown on this medium. even though the previous findings reported the limited selecting power of ms agar for streptococcus strains, the identities of non-streptococcal strains from human oral samples which can grow on this medium are not clear yet. in this study, we identified non-streptococcal organisms grown on ms agar plates by polymerase chain reaction (pc ... | 2015 | 25463904 |
| characterization and in vitro properties of oral lactobacilli in breastfed infants. | lactobacillus species can contribute positively to general and oral health and are frequently acquired by breastfeeding in infancy. the present study aimed to identify oral lactobacilli in breast and formula-fed 4 month-old infants and to evaluate potential probiotic properties of the dominant lactobacillus species detected. saliva and oral swab samples were collected from 133 infants who were enrolled in a longitudinal study (n=240) examining the effect of a new infant formula on child growth a ... | 2013 | 23945215 |
| reoxidation of the thiol-disulfide oxidoreductase mdba by a bacterial vitamin k epoxide reductase in the biofilm-forming actinobacterium actinomyces oris. | post-translocational protein folding in the gram-positive biofilm-forming actinobacterium actinomyces oris is mediated by a membrane-bound thiol-disulfide oxidoreductase named mdba, which catalyzes oxidative folding of nascent polypeptides transported by the sec translocon. reoxidation of mdba involves a bacterial vitamin k epoxide reductase (vkor)-like protein that contains four cysteine residues c93/c101 and c175/c178 with the latter forming a canonical cxxc thioredoxin-like motif; however, th ... | 2017 | 28289087 |
| bacterial invasion into radicular dentine-an in vitro study. | we wanted to investigate differences in invasiveness into radicular dentinal tubules by monocultured and co-cultured bacteria frequently found in infected root canals. | 2016 | 27722787 |
| high-throughput quantitative method for assessing coaggregation among oral bacterial species. | this paper describes a high-throughput method that relies upon a microplate reader to score coaggregation 60 min postmixing, and use of a high-speed real-time imaging technology to describe the rate of coaggregation over time. the results of visual, microplate, and flowcam(™) aggregation scores for oral bacteria streptococcus gordonii, streptococcus oralis, and actinomyces oris, whose ability to coaggregate are well characterized, are compared. following mixing of all possible pairs, the top fra ... | 2016 | 27455031 |
| genetics and cell morphology analyses of the actinomyces oris srta mutant. | sortase is a cysteine-transpeptidase that anchors lpxtg-containing proteins on the gram-positive bacterial cell wall. previously, sortase was considered to be an important factor for bacterial pathogenesis and fitness, but not cell growth. however, the actinomyces oris sortase is essential for cell viability, due to its coupling to a glycosylation pathway. in this chapter, we describe the methods to generate conditional srta deletion mutants and identify srta suppressors by tn5 transposon mutage ... | 2016 | 27311668 |
| a type i signal peptidase is required for pilus assembly in the gram-positive, biofilm-forming bacterium actinomyces oris. | the gram-positive bacterium actinomyces oris, a key colonizer in the development of oral biofilms, contains 18 lpxtg motif-containing proteins, including fimbrillins that constitute two fimbrial types critical for adherence, biofilm formation, and polymicrobial interactions. export of these protein precursors, which harbor a signal peptide, is thought to be mediated by the sec machine and require cleavage of the signal peptide by type i signal peptidases (spases). like many gram-positive bacteri ... | 2016 | 27215787 |
| oral biofilm and caries-infiltrant interactions on enamel. | this study aimed to analyze interactions between oral biofilms and a dental triethylene glycol dimethacrylate (tegdma)-based resin infiltration material on enamel. | 2016 | 26972979 |
| cnaa domains in bacterial pili are efficient dissipaters of large mechanical shocks. | pathogenic bacteria adhere despite severe mechanical perturbations induced by the host, such as coughing. in gram-positive bacteria, extracellular protein appendages termed pili are necessary for adherence under mechanical stress. however, little is known about the behavior of gram-positive pili under force. here, we demonstrate a mechanism by which gram-positive pili are able to dissipate mechanical energy through mechanical unfolding and refolding of isopeptide bond-delimited polypeptide loops ... | 2016 | 26884173 |
| interactions between streptococcus oralis, actinomyces oris, and candida albicans in the development of multispecies oral microbial biofilms on salivary pellicle. | the fungus candida albicans is carried orally and causes a range of superficial infections that may become systemic. oral bacteria actinomyces oris and streptococcus oralis are abundant in early dental plaque and on oral mucosa. the aims of this study were to determine the mechanisms by which s. oralis and a. oris interact with each other and with c. albicans in biofilm development. spatial distribution of microorganisms was visualized by confocal laser scanning microscopy of biofilms labeled by ... | 2017 | 26834007 |
| interkingdom cooperation between candida albicans, streptococcus oralis and actinomyces oris modulates early biofilm development on denture material. | candida-associated stomatitis affects up to 60% of denture wearers, and candida albicans remains the most commonly isolated fungal species. the oral bacteria actinomyces oris and streptococcus oralis are abundant in early dental plaque. the aims of this study were to determine the effects of s. oralis and a. oris on the development of c. albicans biofilms on denture material. resin discs were coated with saliva and at early (1.5 h) or later (24 h) stages of biofilm development, cell numbers of e ... | 2016 | 26755532 |
| [isolation and identification of aerobic and facultative anaerobic bacteria in the oral cavity]. | to establish a systematic method for isolation and identification of aerobic and facultative anaerobic bacteria in the oral cavity. | 2015 | 26714902 |
| effect of endodontic irrigants on biofilm matrix polysaccharides. | to specifically investigate the effect of endodontic irrigants at their clinical concentration on matrix polysaccharides of cultured biofilms. | 2017 | 26705856 |
| iron-dependent gene expression in actinomyces oris. | actinomyces oris is a gram-positive bacterium that has been associated with healthy and diseased sites in the human oral cavity. most pathogenic bacteria require iron to survive, and in order to acquire iron in the relatively iron-scarce oral cavity a. oris has been shown to produce iron-binding molecules known as siderophores. the genes encoding these siderophores and transporters are thought to be regulated by the amount of iron in the growth medium and by the metal-dependent repressor, amdr, ... | 2015 | 26685151 |
| a disulfide bond-forming machine is linked to the sortase-mediated pilus assembly pathway in the gram-positive bacterium actinomyces oris. | export of cell surface pilins in gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. here, we present physiological studies to demonstrate that the fima pilin of actinomyces oris contains two disulfide bonds. alanine substitution of cysteine residues forming the c-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial ... | 2015 | 26170452 |
| microbial dynamics during conversion from supragingival to subgingival biofilms in an in vitro model. | the development of dental caries and periodontal diseases result from distinct shifts in the microbiota of the tooth-associated biofilm. this in vitro study aimed to investigate changes in biofilm composition and structure, during the shift from a 'supragingival' aerobic profile to a 'subgingival' anaerobic profile. biofilms consisting of actinomyces oris, candida albicans, fusobacterium nucleatum, streptococcus oralis, streptococcus mutans and veillonella dispar were aerobically grown in saliva ... | 2016 | 26033167 |
| streptococcus gordonii dl1 adhesin sspb v-region mediates coaggregation via receptor polysaccharide of actinomyces oris t14v. | streptococcus gordonii sspa and sspb proteins, members of the antigen i/ii (agi/ii) family of streptococcus adhesins, mediate adherence to cysteine-rich scavenger glycoprotein gp340 and cells of other oral microbial species. in this article we investigated further the mechanism of coaggregation between s. gordonii dl1 and actinomyces oris t14v. previous mutational analysis of s. gordonii suggested that sspb was necessary for coaggregation with a. oris t14v. we have confirmed this by showing that ... | 2015 | 25965671 |
| critical roles of arginine in growth and biofilm development by streptococcus gordonii. | streptococcus gordonii is an oral commensal and an early coloniser of dental plaque. in vitro, s. gordonii is conditionally auxotrophic for arginine in monoculture but biosynthesises arginine when coaggregated with actinomyces oris. here, we investigated the arginine-responsive regulatory network of s. gordonii and the basis for conditional arginine auxotrophy. arcb, the catabolic ornithine carbamoyltransferase involved in arginine degradation, was also essential for arginine biosynthesis. howev ... | 2015 | 25855127 |
| a sweet new role for lcp enzymes in protein glycosylation. | the peptidoglycan that surrounds gram-positive bacteria is affixed with a range of macromolecules that enable the microbe to effectively interact with its environment. distinct enzymes decorate the cell wall with proteins and glycopolymers. sortase enzymes covalently attach proteins to the peptidoglycan, while lytr-cpsa-psr (lcp) proteins are thought to attach teichoic acid polymers and capsular polysaccharides. ton-that and colleagues have discovered a new glycosylation pathway in the oral bact ... | 2014 | 25302626 |
| lethality of sortase depletion in actinomyces oris caused by excessive membrane accumulation of a surface glycoprotein. | sortase, a cysteine-transpeptidase conserved in gram-positive bacteria, anchors on the cell wall many surface proteins that facilitate bacterial pathogenesis and fitness. genetic disruption of the housekeeping sortase in several gram-positive pathogens reported thus far attenuates virulence, but not bacterial growth. paradoxically, we discovered that depletion of the housekeeping sortase srta was lethal for actinomyces oris; yet, all of its predicted cell wall-anchored protein substrates (acaa-n ... | 2014 | 25230351 |
| axenic culture of a candidate division tm7 bacterium from the human oral cavity and biofilm interactions with other oral bacteria. | the diversity of bacterial species in the human oral cavity is well recognized, but a high proportion of them are presently uncultivable. candidate division tm7 bacteria are almost always detected in metagenomic studies but have not yet been cultivated. in this paper, we identified candidate division tm7 bacterial phylotypes in mature plaque samples from around orthodontic bonds in subjects undergoing orthodontic treatment. successive rounds of enrichment in laboratory media led to the isolation ... | 2014 | 25107981 |
| s-aryl-l-cysteine sulphoxides and related organosulphur compounds alter oral biofilm development and ai-2-based cell-cell communication. | to design and synthesize a library of structurally related, small molecules related to homologues of compounds produced by the plant petiveria alliacea and determine their ability to interfere with ai-2 cell-cell communication and biofilm formation by oral bacteria. many human diseases are associated with persistent bacterial biofilms. oral biofilms (dental plaque) are problematic as they are often associated with tooth decay, periodontal disease and systemic disorders such as heart disease and ... | 2014 | 25081571 |
| colonisation of gingival epithelia by subgingival biofilms in vitro: role of "red complex" bacteria. | biofilm formation on tooth surface results in colonisation and invasion of the juxtaposed gingival tissue, eliciting strong inflammatory responses that lead to periodontal disease. this in vitro study investigated the colonisation of human gingival multi-layered epithelium by multi-species subgingival biofilms, and evaluated the relative effects of the "red complex" species (porphyromonas gingivalis, tannerella forsythia and treponema denticola). | 2014 | 24949828 |
| red wine and oenological extracts display antimicrobial effects in an oral bacteria biofilm model. | the antimicrobial effects of red wine and its inherent components on oral microbiota were studied by using a 5-species biofilm model of the supragingival plaque that includes actinomyces oris, fusobacterium nucleatum, streptococcus oralis, streptococcus mutans and veillonella dispar. microbiological analysis (cfu counting and confocal laser scanning microscopy) of the biofilms after the application of red wine, dealcoholized red wine, and red wine extract solutions spiked or not with grape seed ... | 2014 | 24773294 |
| pilus hijacking by a bacterial coaggregation factor critical for oral biofilm development. | the formation of dental plaque, a highly complex biofilm that causes gingivitis and periodontitis, requires specific adherence among many oral microbes, including the coaggregation of actinomyces oris with streptococcus oralis that helps to seed biofilm development. here, we report the discovery of a key coaggregation factor for this process. this protein, which we named coaggregation factor a (cafa), is one of 14 cell surface proteins with the lpxtg motif predicted in a. oris mg1, whose functio ... | 2014 | 24567409 |
| adhesion of streptococcus mitis and actinomyces oris in co-culture to machined and anodized titanium surfaces as affected by atmosphere and ph. | with the rising demand for osseointegrated titanium implants for replacing missing teeth, often in patients with a history of periodontitis, implant-related infections have become an issue of growing concern. novel methods for treating and preventing implant-associated infections are urgently needed. the aim of this study was to investigate if different ph, atmosphere and surface properties could restrict bacterial adhesion to titanium surfaces used in dental implants. | 2013 | 23298213 |
| identification of the genes involved in the biofilm-like structures on actinomyces oris k20, a clinical isolate from an apical lesion. | although the production of biofilm is thought to be crucial in the pathogenesis of abscess formations caused by oral resident microorganisms, the particular mechanisms are still unknown. the aim of this study was to identify gene(s) responsible for maintaining the cell surface-associated meshwork-like structures, which are found in some biofilm-producing bacteria, in a clinical isolate of actinomyces oris k20. | 2013 | 23228256 |
| the pilin protein fimp from actinomyces oris: crystal structure and sequence analyses. | the actinomyces oris type-1 pili are important for the initial formation of dental plaque by binding to salivary proteins that adhere to the tooth surface. here we present the x-ray structure of fimp, the protein that is polymerized into the type-1 pilus stalk, assisted by a pili-specific sortase. fimp consists of three tandem igg-like domains. the middle and c-terminal domains contain one autocatalyzed intramolecular isopeptide bond each, a feature used by gram-positive bacteria for stabilizati ... | 2012 | 23118994 |
| strain-specific colonization patterns and serum modulation of multi-species oral biofilm development. | periodontitis results from an ecological shift in the composition of subgingival biofilms. subgingival community maturation is modulated by inter-organismal interactions and the relationship of communities with the host. in an effort to better understand this process, we evaluated biofilm formation, with oral commensal species, by three strains of the subgingivally prevalent microorganism fusobacterium nucleatum and four strains of the periodontopathogen porphyromonas gingivalis. we also tested ... | 2012 | 22771792 |
| structural determinants of actinomyces sortase srtc2 required for membrane localization and assembly of type 2 fimbriae for interbacterial coaggregation and oral biofilm formation. | as a pioneer colonizer of the oral cavity, actinomyces oris expresses proteinaceous pili (also called fimbriae) to mediate the following two key events in biofilm formation: adherence to saliva deposits on enamel and interbacterial associations. assembly of type 2 fimbriae that directly facilitate coaggregation with oral streptococci and actinomyces biofilm development requires the class c sortase srtc2. although the general sortase-associated mechanisms have been elucidated, several structural ... | 2012 | 22447896 |
| disulfide bonds: a key modification in bacterial extracytoplasmic proteins. | disulfide bonds are a common posttranslational modification that contributes to the folding and stability of extracytoplasmic proteins. almost all organisms, from eukaryotes to prokaryotes, have evolved enzymes to make and break these bonds. accurate and efficient disulfide bond formation can be vital for protein function; therefore, the enzymes that catalyze disulfide bond formation are involved in multiple biological processes. recent advances clearly show that oral bacteria also have the abil ... | 2017 | 28797211 |
| effect of ultraviolet treatment on bacterial attachment and osteogenic activity to alkali-treated titanium with nanonetwork structures. | alkali-treated titanium with nanonetwork structures (tns) possesses good osteogenic activity; however, the resistance of this material to bacterial contamination remains inadequate. as such, tns implants are prone to postoperative infection. in this work, we attempted to alter the biological properties of tns by treatment with short-duration high-intensity ultraviolet (uv) irradiation. | 2017 | 28721040 |
| electron transport chain is biochemically linked to pilus assembly required for polymicrobial interactions and biofilm formation in the gram-positive actinobacterium actinomyces oris. | the gram-positive actinobacteria actinomyces spp. are key colonizers in the development of oral biofilms due to the inherent ability of actinomyces to adhere to receptor polysaccharides on the surface of oral streptococci and host cells. this receptor-dependent bacterial interaction, or coaggregation, requires a unique sortase-catalyzed pilus consisting of the pilus shaft fima and the coaggregation factor cafa forming the pilus tip. while the essential role of the sortase machine srtc2 in pilus ... | 2017 | 28634238 |