| phylogenetic analysis of cultivable oral treponemes from the smibert collection. | dr. robert smibert from the virginia polytechnic institute, usa, isolated and collected over 200 strains of oral treponemes over a 20-year period. dr. smibert, dr. w.e.c. moore and dr. l.v. moore separated these isolates and reference strains into different groups on the basis of cellular fatty acid analysis. in this study, the 16s rrna genes were sequenced for 47 strains that were representative of these groups. five distinct species were identified on the basis of 16s rrna sequence comparisons ... | 1998 | 9734025 |
| surface structure, hydrophobicity, phagocytosis, and adherence to matrix proteins of bacillus cereus cells with and without the crystalline surface protein layer. | nonopsonic phagocytosis of bacillus cereus by human polymorphonuclear leukocytes (pmns) with particular attention to bacterial surface properties and structure was studied. two reference strains (atcc 14579(t) and atcc 4342) and two clinical isolates (oh599 and oh600) from periodontal and endodontic infections were assessed for adherence to matrix proteins, such as type i collagen, fibronectin, laminin, and fibrinogen. one-day-old cultures of strains oh599 and oh600 were readily ingested by pmns ... | 1998 | 9746594 |
| risk indicators for harboring periodontal pathogens. | the risk for harboring 6 putative periodontal pathogens in 4 selected periodontal pockets, in whole saliva, or in either site (i.e., orally) was determined in 52 caucasians, 49 african-americans, 48 asian-americans, and 50 hispanics living in los angeles. 16s rrna pcr analysis assessed the presence of actinobacillus actinomycetemcomitans, bacteroides forsythus, porphyromonas gingivalis, prevotella intermedia, prevotella nigrescens, and treponema denticola. step-wise regression analysis determine ... | 1998 | 9802709 |
| local metronidazole application in maintenance patients. clinical and microbiological evaluation. | the purpose of this investigation was to evaluate the clinical and microbiological effect of local antibiotic therapy in comparison with subgingival scaling and root planing in a randomized semi-masked study. forty-six recall patients who completed systematic periodontal therapy 6 to 24 months prior to the study were enrolled. the inclusion requirements were at least one site with probing depth > or = 5 mm in each quadrant, no scaling, and no antibiotic therapy during the last 6 months. after ra ... | 1998 | 9802715 |
| flagellins, but not endoflagellar sheath proteins, of treponema pallidum and of pathogen-related oral spirochetes are glycosylated. | glycosylation of the flagellar core proteins (flabs) was detected in treponema pallidum nichols and in the type or reference strains of seven oral treponema species. in several nonmotile strains of oral treponemes, the flabs were undetectable by both antibody and glycan staining. in contrast, a spontaneous low-motility variant of t. vincenti poundi-related strain ritza, omz 305a, lacked the flagellar sheath protein (flaa) and the two glycan-staining flab bands of the wild type, but antibody labe ... | 1998 | 9826350 |
| sialic acid-dependent recognition of laminin by penicillium marneffei conidia. | immunofluorescence microscopy demonstrated that laminin bound to the surface of penicillium marneffei conidia. attachment of p. marneffei conidia in an adherence assay was inhibited by soluble laminin and anti-laminin antibody. n-acetylneuraminic acid abolished adherence, indicating an interaction mediated by a sialic acid-specific lectin. | 1998 | 9826390 |
| aspartate transcarbamylase from the hyperthermophilic eubacterium thermotoga maritima: fused catalytic and regulatory polypeptides form an allosteric enzyme. | in the allosteric aspartate transcarbamylase (atcase) from the hyperthermophilic eubacterium thermotoga maritima, the catalytic and regulatory functions, which in class b atcases are carried out by specialized polypeptides, are combined on a single type of polypeptide assembled in trimers. the atcases from t. maritima and treponema denticola present intriguing similarities, suggesting horizontal gene transfer. | 1998 | 9829951 |
| life below the gum line: pathogenic mechanisms of porphyromonas gingivalis. | porphyromonas gingivalis, a gram-negative anaerobe, is a major etiological agent in the initiation and progression of severe forms of periodontal disease. an opportunistic pathogen, p. gingivalis can also exist in commensal harmony with the host, with disease episodes ensuing from a shift in the ecological balance within the complex periodontal microenvironment. colonization of the subgingival region is facilitated by the ability to adhere to available substrates such as adsorbed salivary molecu ... | 1998 | 9841671 |
| relationship between c-telopeptide pyridinoline cross-links (ictp) and putative periodontal pathogens in periodontitis. | crevicular fluid pyridinoline cross-linked carboxyterminal telopeptide of type i collagen (ictp) is predictive for future alveolar bone loss in experimental periodontitis in dogs. the present study sought to relate ictp to a panel of subgingival species in subjects exhibiting various clinical presentations such as health (n=7), gingivitis (n=8) and periodontitis (n=21). 28 subgingival plaque and gcf samples were taken from mesiobuccal sites in each of 36 subjects. the presence and levels of 40 s ... | 1998 | 9846794 |
| identification and sequence analysis of treponema pallidum tprj, a member of a polymorphic multigene family. | tnphoa mutagenesis was used to identify genes encoding exported proteins in a genomic dna library of treponema pallidum, the syphilis agent. the nucleotide sequence of an open reading frame (tprj) that encodes a 755-amino acid protein with a predicted molecular mass of 81.1 kda was determined. the deduced amino acid sequence of tprj has homology to the major surface protein of treponema denticola, a periodontal pathogen. southern hybridization and genomic dna sequence analysis indicate that tprj ... | 1998 | 9851047 |
| the genome of treponema pallidum: new light on the agent of syphilis. | treponema pallidum subsp, pallidum, the causative agent of the sexually transmitted disease syphilis, is a fastidious, microaerophilic obligate parasite of humans. this bacterium is one of the few prominent infectious agents that has not been cultured continuously in vitro and consequently relatively little is known about its virulence mechanisms at the molecular level. t. pallidum therefore represented an attractive candidate for genomic sequencing. the complete genome sequence of t. pallidum h ... | 1998 | 9862125 |
| effect of temperature and viscosity on the motility of the spirochete treponema denticola. | treponema denticola is an oral spirochete associated with periodontal diseases. because bacterial motility is likely to be a potential virulence factor, we investigated the effect of viscosity and temperature on cell speed. in agreement with the work of others, translational motility was a function of the macroscopic viscosity of the medium. in addition, we found that although the speed of spirochetes was slow at 25 degrees c (4 microns s-1), it increased quite markedly at 35 degrees c (19 micro ... | 1998 | 9868769 |
| virulence of a polymicrobic complex, treponema denticola and porphyromonas gingivalis, in a murine model. | the effect of a polymicrobic infection employing treponema denticola and porphyromonas gingivalis in the murine lesion model was used to determine the synergistic virulence of these two periodontopathic bacteria. at high doses of p. gingivalis w50, addition of t. denticola in the infection mixture had no effect on the formation and size of the spreading lesion caused by this microorganism. however, at low p. gingivalis challenge doses, t. denticola significantly enhanced the virulence of p. ging ... | 1998 | 9872114 |
| binding and utilization of human transferrin by prevotella nigrescens. | to survive and multiply within their hosts, pathogens must possess efficient iron-scavenging mechanisms. in the present study, we investigate the capacity of prevotella nigrescens and prevotella intermedia to use various sources of iron for growth and characterize the transferrin-binding activity of p. nigrescens. iron-saturated human transferrin and lactoferrin, but not ferric chloride and the iron-free form of transferrin, could be used as sources of iron by p. nigrescens and p. intermedia. ne ... | 1999 | 9916061 |
| characterization of a novel methyl-accepting chemotaxis gene, dmcb, from the oral spirochete treponema denticola. | immediately downstream from the previously isolated treponema denticola atcc 35405 prtb gene coding for a chymotrypsinlike protease activity, an open reading frame, orf3, was identified which shared significant homology with the highly conserved domains (hcds) of bacterial methyl-accepting chemotaxis proteins (mcps). nucleotide sequencing of this orf revealed that the gene would code for a protein with a size of approximately 41 kda. in addition, this sequence contained a domain which was virtua ... | 1999 | 9916079 |
| cloning and characterization of a gene (mspa) encoding the major sheath protein of treponema maltophilum atcc 51939(t). | the major sheath protein-encoding gene (mspa) of the oral spirochete treponema maltophilum atcc 51939(t) was cloned by screening a genomic library with an anti-outer membrane fraction antibody. the mspa gene encodes a precursor protein of 575 amino acids with a predicted molecular mass of 62.3 kda, including a signal peptide of 19 amino acids. the native mspa formed a heat-modifiable, detergent- and trypsin-stable complex which is associated with the outer membrane. hybridization with an mspa-sp ... | 1999 | 9922270 |
| the borrelia burgdorferi 37-kilodalton immunoblot band (p37) used in serodiagnosis of early lyme disease is the flaa gene product. | the 37-kda protein (p37) of borrelia burgdorferi is an antigen that elicits an early immunoglobulin m (igm) antibody response in lyme disease patients. the p37 gene was cloned from a b. burgdorferi genomic library by screening with antibody from a lyme disease patient who had developed a prominent humoral response to the p37 antigen. dna sequence analysis of this clone revealed the identity of p37 to be flaa, an outer sheath protein of the periplasmic flagella. recombinant p37 expression was acc ... | 1999 | 9986810 |
| identification of seven treponema species in health- and disease-associated dental plaque by nested pcr. | species-specific nested pcr was used to detect treponema amylovorum, treponema denticola, treponema maltophilum, treponema medium, treponema pectinovorum, treponema socranskii, and treponema vincentii in dental plaque. subjects with periodontitis harbored all species, but t. pectinovorum and t. vincentii were not found in plaque from disease-free subjects. | 1999 | 9986879 |
| treponema pallidum major sheath protein homologue tpr k is a target of opsonic antibody and the protective immune response. | we have identified a family of genes that code for targets for opsonic antibody and protective immunity in t. pallidum subspecies pallidum using two different approaches, subtraction hybridization and differential immunologic screening of a t. pallidum genomic library. both approaches led to the identification of a polymorphic multicopy gene family with predicted amino acid homology to the major sheath protein of treponema denticola. one of the members of this gene family, tpr k, codes for a pro ... | 1999 | 9989979 |
| activation of murine macrophages by lipoprotein and lipooligosaccharide of treponema denticola. | we have recently demonstrated that the periodontopathogenic oral spirochete treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (los). the aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases. an enriched lipoprotein fraction (dlpp) from t. denticola atcc 35404 obt ... | 1999 | 10024558 |
| treponema denticola outer membrane enhances the phagocytosis of collagen-coated beads by gingival fibroblasts. | human gingival fibroblasts (hgfs) degrade collagen fibrils in physiological processes by phagocytosis. since treponema denticola outer membrane (om) extract perturbs actin filaments, important structures in phagocytosis, we determined whether the om affects collagen phagocytosis in vitro by hgfs. phagocytosis was measured by flow cytometric assessment of internalized collagen-coated fluorescent latex beads. confluent hgfs pretreated with t. denticola atcc 35405 om exhibited an increase in the pe ... | 1999 | 10024564 |
| serological evidence of spirochaetal infections associated with digital dermatitis in dairy cattle. | a potentially infectious aetiology for digital dermatitis in dairy cattle was investigated and centred on the possible involvement of spirochaetes. an enzyme-linked immunosorbent assay (elisa) was developed to detect bovine anti-borrelia burgdorferi (b31) and anti-treponeme (usa bovine isolates) antibodies in the sera of cows; sera were further tested for antigen specificity by western blotting. compared to normal cows, those with digital dermatitis had a much higher seropositivity rate to b. bu ... | 1999 | 10030131 |
| esterases in serum-containing growth media counteract chloramphenicol acetyltransferase activity in vitro. | the spirochete borrelia burgdorferi was unexpectedly found to be as susceptible to diacetyl chloramphenicol, the product of the enzyme chloramphenicol acetyltransferase, as it was to chloramphenicol itself. the susceptibilities of escherichia coli and bacillus subtilis, as well as that of b. burgdorferi, to diacetyl chloramphenicol were then assayed in different media. all three species were susceptible to diacetyl chloramphenicol when growth media were supplemented with rabbit serum or, to a le ... | 1999 | 10049283 |
| molecular cloning, sequencing, and expression of a novel multidomain mannanase gene from thermoanaerobacterium polysaccharolyticum. | the mana gene of thermoanaerobacterium polysaccharolyticum was cloned in escherichia coli. the open reading frame of mana is composed of 3,291 bases and codes for a preprotein of 1,097 amino acids with an estimated molecular mass of 119,627 da. the start codon is preceded by a strong putative ribosome binding site (taaggcggtg) and a putative -35 (ttcgc) and -10 (taaaat) promoter sequence. the mana of t. polysaccharolyticum is a modular protein. sequence comparison and biochemical analyses demons ... | 1999 | 10049399 |
| use of pcr and sodium dodecyl sulfate-polyacrylamide gel electrophoresis techniques for differentiation of prevotella intermedia sensu stricto and prevotella nigrescens. | primers were designed from 16s rrna sequences of prevotella intermedia sensu stricto and prevotella nigrescens and were used to discriminate these two species by pcr. the results were compared with those from the pcr technique using primers designed from arbitrarily primed pcr products by guillot and mouton (e. guillot and c. mouton, j. clin. microbiol. 35:1876-1882, 1997). the specificities of both assays were studied by using p. intermedia atcc 25611, p. nigrescens atcc 33563, 174 clinical iso ... | 1999 | 10074526 |
| cystalysin, a 46-kda l-cysteine desulfhydrase from treponema denticola: biochemical and biophysical characterization. | a 46-kda hemolytic protein referred to as cystalysin, from treponema denticola atcc 35404, was characterized and overexpressed in escherichia coli lc-67. cystalysin lysed erythrocytes, hemoxidized hemoglobin to sulfhemoglobin and methemoglobin, and removed the sulfhydryl and amino group from selected s-containing compounds (e.g., cysteine) producing h2s, nh3, and pyruvate. with l-cysteine as substrate, cystalysin obeys michaelis-menten kinetics. cystathionine and s-aminoethyl-l-cysteine were als ... | 1999 | 10194060 |
| direct quantification of the enteric bacterium oxalobacter formigenes in human fecal samples by quantitative competitive-template pcr. | homeostasis of oxalic acid appears to be regulated, in part, by the gut-associated bacterium oxalobacter formigenes. the loss of this bacterium from the gut flora is associated with an increased susceptibility to hyperoxaluria, a condition which can lead to the formation of calcium oxalate crystalluria and kidney stones. in order to identify and quantify the presence of o. formigenes in clinical specimens, a quantitative-pcr-based assay system utilizing a competitive dna template as an internal ... | 1999 | 10203513 |
| restriction fragment-length polymorphism analysis of 16s ribosomal rna genes amplified by polymerase chain reaction for rapid identification of cultivable oral treponemes. | although oral treponemes are among the most frequently found bacteria in periodontal pockets, identification of these organisms can be difficult. in this study, restriction fragment-length polymorphism (rflp) analysis of polymerase chain reaction (pcr)-amplified 16s ribosomal rna genes (16s rrna gene pcr-rflp) was used to generate restriction profiles of reference strains of oral treponemes including treponema denticola, treponema socranskii, treponema vincentii. treponema pectinovorum and trepo ... | 1999 | 10219171 |
| environmental modulation of oral treponeme virulence in a murine model. | this investigation examined the effects of environmental alteration on the virulence of the oral treponemes treponema denticola and treponema pectinovorum. the environmental effects were assessed by using a model of localized inflammatory abscesses in mice. in vitro growth of t. denticola and t. pectinovorum as a function of modification of the cysteine concentration significantly enhanced abscess formation and size. in contrast, growth of t. denticola or t. pectinovorum under iron-limiting cond ... | 1999 | 10338481 |
| mitogenic activity of the outer membrane of treponema denticola. | the outer membrane (om) was isolated by detergent extraction from treponema denticola atcc 35405, atcc 33521 and atcc 35404, representing serovars a, b and c, respectively, as well as from two fresh isolates of t. denticola. strict precautions were undertaken against the introduction of contaminant lipopolysaccharide when the om was isolated. the om was active in mitogenic stimulation of c3h/heouj mouse spleen cultures, but to a somewhat lesser extent than purified lipopolysaccharide (lps) from ... | 1998 | 10347901 |
| erythromycin-resistant neisseria gonorrhoeae and oral commensal neisseria spp. carry known rrna methylase genes. | two neisseria gonorrhoeae isolates from seattle and two isolates from uruguay were resistant to erythromycin (mic, 4 to 16 microg/ml) and had reduced susceptibility to azithromycin (mic, 1 to 4 microg/ml) due to the presence of the self-mobile rrna methylase gene(s) ermf or ermb and ermf. the two seattle isolates and one isolate from uruguay were multiresistant, carrying either the 25.2-mda tetm-containing plasmid (seattle) or a beta-lactamase plasmid (uruguay). sixteen commensal neisseria isola ... | 1999 | 10348754 |
| relationship between herpesviruses and adult periodontitis and periodontopathic bacteria. | various mammalian viruses and specific bacteria seem to play important roles in the pathogenesis of human periodontitis. this study examined the relationship between subgingival herpesviruses and periodontal disease and potential periodontopathic bacteria in 140 adults exhibiting either periodontitis or gingivitis. | 1999 | 10368051 |
| insertional inactivation of treponema denticola tap1 results in a nonmotile mutant with elongated flagellar hooks. | the treponemal fla operon is comprised of numerous motility-related genes; however, the initial gene of this operon, tap1, has no known function. a recently developed system to generate specific mutants in treponema denticola was utilized to determine if tap1 was essential for motility. t. denticola tap1 and flanking dna were identified, cloned, and sequenced, and a suicide plasmid that contained tap1 interrupted with an erythromycin resistance cassette (ermf and ermam) was constructed. because ... | 1999 | 10368149 |
| development of a system for expressing heterologous genes in the oral spirochete treponema denticola and its use in expression of the treponema pallidum flaa gene. | the present communication describes the construction of a new escherichia coli-treponema denticola shuttle vector based on the naturally occurring spirochete plasmid pts1 and the expression of the heterologous t. pallidum flaa gene from the plasmid in t. denticola. this new shuttle vector system should prove useful in characterizing virulence factors from unculturable pathogenic spirochetes. | 1999 | 10377154 |
| inability of intact cells of treponema denticola to degrade human serum proteins iga, igg and albumin. | treponema denticola has been shown to be associated with periodontitis in man and animals. the organism ferments amino acids and thrives on the proteins in the periodontal pocket. accordingly, t. denticola possesses various proteolytic enzymes, including a chymotrypsin-like protease, capable of hydrolyzing a whole range of proteins, including immunoglobulins. yet, it is not clear whether the intact cells of t. denticola can degrade immunoglobulins and albumin. the purpose of this study was to cl ... | 1999 | 10412854 |
| the treponema denticola major sheath protein is predominantly periplasmic and has only limited surface exposure. | the recent discovery that the treponema pallidum genome encodes 12 orthologs of the treponema denticola major sheath protein (msp) prompted us to reexamine the cellular location and topology of the t. denticola polypeptide. experiments initially were conducted to ascertain whether msp forms an array on or within the t. denticola outer membrane. transmission electron microscopy (em) of negatively stained and ultrathin-sectioned organisms failed to identify a typical surface layer, whereas freeze- ... | 1999 | 10417176 |
| molecular characterization of a flagellar (fla) operon in the oral spirochete treponema denticola atcc 35405. | a treponema denticola 9.6-kb motility locus containing 11 genes was identified, sequenced and analyzed. the genes were designated tap1, flgd, flge, orf4, mota, motb, flil, flim, fliy, orf10 and flip. the order of these genes is identical to that of the corresponding region of the treponema pallidum fla operon. seven of the deduced fla proteins share significant homology with both escherichia coli and bacillus subtilis proteins associated with flagellar structure and function. reverse transcripti ... | 1999 | 10481082 |
| the c-terminal domain of the bordetella pertussis autotransporter brka forms a pore in lipid bilayer membranes. | brka is a 103-kda outer membrane protein of bordetella pertussis that mediates resistance to antibody-dependent killing by complement. it is proteolytically processed into a 73-kda n-terminal domain and a 30-kda c-terminal domain as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. brka is also a member of the autotransporter family of proteins. translocation of the n-terminal domain of the protein across the outer membrane is hypothesized to occur through a pore formed by ... | 1999 | 10482528 |
| sulfhemoglobin formation in human erythrocytes by cystalysin, an l-cysteine desulfhydrase from treponema denticola. | cystalysin, isolated from the oral pathogen treponema denticola, is an l-cysteine desulfhydrase (producing pyruvate, ammonia and hydrogen sulfide from cysteine) that can modify hemoglobin and has hemolytic activity. here, we show that enzymatic activity of recombinant cystalysin depends upon stochiometric pyridoxal phosphate. the enzyme was not functional as an l-alanine transaminase, and had a strong preference for l-cysteine over d-cysteine. cystalysin preferred small alpha-l-amino acids as su ... | 1999 | 10495709 |
| identification and characterization of a determinant (eep) on the enterococcus faecalis chromosome that is involved in production of the peptide sex pheromone cad1. | plasmid-free strains of enterococcus faecalis secrete a peptide sex pheromone, cad1, which specifically induces a mating response by donors carrying the hemolysin plasmid pad1 or related elements. a determinant on the e. faecalis og1x chromosome has been found to encode a 46.5-kda protein that plays an important role in the production of the extracellular cad1. wild-type e. faecalis og1x cells harboring a plasmid chimera carrying the determinant exhibited an eightfold enhanced production of cad1 ... | 1999 | 10498702 |
| improved multiplex pcr using conserved and species-specific 16s rrna gene primers for simultaneous detection of actinobacillus actinomycetemcomitans, bacteroides forsythus, and porphyromonas gingivalis. | among putative periodontal pathogens, actinobacillus actinomycetemcomitans, bacteroides forsythus, and porphyromonas gingivalis are most convincingly implicated as etiological agents in periodontitis. therefore, techniques for detection of those three species would be of value. we previously published a description of a multiplex pcr that detects a. actinomycetemcomitans and p. gingivalis. the present paper presents an improvement on that technique, which now allows more sensitive detection of a ... | 1999 | 10523542 |
| phenotypic and genotypic heterogeneity among cultivable pathogen-related oral spirochetes and treponema vincentii. | recent findings challenge the assumption that pathogen-related oral spirochetes (pros) are related to treponema pallidum. treponema vincentii, grown in omiz-pat media, cross-reacted with monoclonal antibody h9-2 against t. pallidum, and cultivable pros had 16s rrna gene sequences similar to those of t. vincentii (c.-b. choi, c. wyss, and u. b. göbel. j. clin. microbiol. 34:1922-1925, 1996). aims of the present study were to determine whether antigen phenotypes of oral treponemas were influenced ... | 1999 | 10523573 |
| identification by subtractive hybridization of a novel insertion sequence specific for virulent strains of porphyromonas gingivalis. | subtractive hybridization was employed to isolate specific genes from virulent porphyromonas gingivalis strains that are possibly related to abscess formation. the genomic dna from the virulent strain p. gingivalis w83 was subtracted with dna from the avirulent strain atcc 33277. three clones unique to strain w83 were isolated and sequenced. the cloned dna fragments were 885, 369, and 132 bp and had slight homology with only bacillus stearothermophilus is5377, which is a putative transposase. th ... | 1999 | 10531208 |
| lack of humoral immune protection against treponema denticola virulence in a murine model. | this study investigated the characteristics of humoral immune responses to treponema denticola following primary infection, reinfection, and active immunization, as well as immune protection in mice. primary infection with t. denticola induced a significant (400-fold) serum immunoglobulin g (igg) response compared to that in control uninfected mice. the igg response to reinfection was 20, 000-fold higher than that for control mice and 10-fold higher than that for primary infection. mice actively ... | 1999 | 10531223 |
| genetic and structural analyses of cytoplasmic filaments of wild-type treponema phagedenis and a flagellar filament-deficient mutant. | unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. their function is unknown, but their location underneath the periplasmic flagellar filaments (pff) suggests a role in motility and/or cell structure. to better understand these unique structures, the gene coding for the cytoplasmic filaments, cfpa, was identified in various treponemal species. treponema phagedenis cfpa was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence ... | 1999 | 10542176 |
| isolation, cloning, and expression of an acid phosphatase containing phosphotyrosyl phosphatase activity from prevotella intermedia. | a novel acid phosphatase containing phosphotyrosyl phosphatase (ptpase) activity, designated piacp, from prevotella intermedia atcc 25611, an anaerobe implicated in progressive periodontal disease, has been purified and characterized. piacp, a monomer with an apparent molecular mass of 30 kda, did not require divalent metal cations for activity and was sensitive to orthovanadate but highly resistant to okadaic acid. the enzyme exhibited substantial activity against tyrosine phosphate-containing ... | 1999 | 10559178 |
| acquisition of plasmin activity by fusobacterium nucleatum subsp. nucleatum and potential contribution to tissue destruction during periodontitis. | fusobacterium nucleatum subsp. nucleatum has been associated with a variety of oral and nonoral infections such as periodontitis, pericarditis, bone infections, and brain abscesses. several studies have shown the role of plasmin, a plasma serine protease, in increasing the invasive capacity of microorganisms. in this study, we investigated the binding of human plasminogen to f. nucleatum subsp. nucleatum, and its subsequent activation into plasmin. plasminogen-binding activity of bacterial cells ... | 1999 | 10569761 |
| pre- and post-implantation microbiota of the tongue, teeth, and newly placed implants. | this investigation sought intra-oral sources of species colonizing dental implants. | 1999 | 10599911 |
| the tprk gene is heterogeneous among treponema pallidum strains and has multiple alleles. | we have previously shown that the tprk antigen of t. pallidum, nichols strain, is predominantly expressed in treponemes obtained 10 days after infection and that the hydrophilic domain of tprk is a target of opsonic antibodies and confers significant protection against homologous challenge. the t. pallidum genome sequence reported the presence of a single copy of the tprk gene in the nichols strain. in the present study we demonstrate size heterogeneity in the central portions of the tprk hydrop ... | 2000 | 10639452 |
| periodontopathic bacteria in children with down syndrome. | it is widely known that individuals with down syndrome (ds) often develop severe early-onset periodontal diseases. in this study, we examined the prevalence of periodontopathic bacteria in ds children to determine if specific pathogens are acquired in their childhood. | 2000 | 10711615 |
| identification of a treponema denticola oppa homologue that binds host proteins present in the subgingival environment. | proteins secreted or exported by treponema denticola have been implicated as mediators of specific interactions between the spirochete and subgingival tissues in periodontal diseases. however, limited information is available on the ability of this peptidolytic organism to bind or transport soluble peptides present in the subgingival environment. a prominent 70-kda protein was isolated from surface extracts of t. denticola atcc 35405. a clone expressing a portion of the protein was identified in ... | 2000 | 10722578 |
| induction of apoptotic cell death in peripheral blood mononuclear and polymorphonuclear cells by an oral bacterium, fusobacterium nucleatum. | it is largely unknown why a variety of bacteria present in the oral cavity are capable of establishing themselves in the periodontal pockets of nonimmunocompromised individuals in the presence of competent immune effector cells. in this paper we present evidence for the immunosuppressive role of fusobacterium nucleatum, a gram-negative oral bacterium which plays an important role in the generation of periodontal disease. our studies indicate that the immunosuppressive role of f. nucleatum is lar ... | 2000 | 10722579 |
| multiple alleles of treponema pallidum repeat gene d in treponema pallidum isolates. | two new tprd alleles have been identified in treponema pallidum: tprd2 is found in 7 of 12 t. pallidum subsp. pallidum isolates and 7 of 8 non-pallidum isolates, and tprd3 is found in one t. pallidum subsp. pertenue isolate. antibodies against tprd2 are found in persons with syphilis, demonstrating that tprd2 is expressed during infection. | 2000 | 10735882 |
| herpesviruses in human periodontal disease. | recent studies have identified various herpesviruses in human periodontal disease. epstein-barr virus type 1 (ebv-1) infects periodontal b-lymphocytes and human cytomegalovirus (hcmv) infects periodontal monocytes/ macrophages and t-lymphocytes. ebv-1, hcmv and other herpesviruses are present more frequently in periodontitis lesions and acute necrotizing ulcerative gingivitis-lesions than in gingivitis or periodontally healthy sites. reactivation of hcmv in periodontitis lesions tends to be asso ... | 2000 | 10791704 |
| the prevalence of pathogenic periodontal microflora in healthy young adult smokers. | smoking is a major risk factor in periodontitis, although the mechanisms of its effects are not well understood. the overall goal of this clinical study was to determine if smoking enhances the colonization of the oral cavity by pathogenic bacteria in a periodontitis-free population. the prevalence of actinobacillus actinomycetemcomitans, porphyromonas gingivalis, prevotella intermedia, fusobacterium nucleatum, campylobacter rectus, eikenella corrodens, bacteroides forsythus, and treponema denti ... | 2000 | 10807119 |
| listeriolysin o as a reporter to identify constitutive and in vivo-inducible promoters in the pathogen listeria monocytogenes. | listeria monocytogenes is a facultative intracellular gram-positive bacterium capable of growing in the cytoplasm of infected host cells. bacterial escape from the phagosomal vacuole of infected cells is mainly mediated by the pore-forming hemolysin listeriolysin o (llo) encoded by hly. llo-negative mutants of l. monocytogenes are avirulent in the mouse model. we have developed a genetic system with hly as a reporter gene allowing the identification of both constitutive and in vivo-inducible pro ... | 2000 | 10816469 |
| periodontopathic bacteria in english hiv-seropositive persons. | selected periodontopathic bacteria were sought in 20 hiv-infected english patients and eight noninfected control subjects with similar periodontal status, using highly specific dna probes. actinobacillus actinomycetemcomitans (a. a), porphyromonas gingivalis, campylobacter rectus, prevotella intermedia, and fusobacterium nucleatum were more frequently detected and were found at higher levels in hiv-infected individuals than in controls. significantly increased levels of treponema denticola but, ... | 1999 | 10842858 |
| prevaccination with srl172 (heat-killed mycobacterium vaccae) inhibits experimental periodontal disease in wistar rats. | periodontal disease is a bacterial dental plaque-induced destructive inflammatory condition of the tooth-supporting tissues, which is thought to be mediated by t lymphocytes secreting t helper 2 (th2) cytokines, resulting in recruitment of high numbers of antibody-producing b lymphocytes/plasma cells as well as polymorphonuclear leucocytes (pmn) secreting tissue-destructive components, such at matrix metalloproteinases and reactive oxygen metabolites into the gingival connective tissues. one tre ... | 2000 | 10844524 |
| checkerboard dna-dna hybridization analysis of endodontic infections. | the purpose of this investigation was to examine the microbiota of infected root canals by using a molecular genetic method. | 2000 | 10846131 |
| taxonomic study of spirochetes isolated from human periodontal lesions. | nineteen strains of spirochetes obtained from subgingival plaque of 19 patients with advanced periodontitis were studied morphologically, biochemically, and genetically and compared with type strains of treponema denticola and treponema socranskii. the results showed that 16 strains which biochemically resembled t. denticola could be divided into two groups based on g + c content and dna homology. two isolates appeared to belong to the t. socranskii species. one intermediate size isolate did not ... | 1987 | 10870473 |
| spirochaetal lipoproteins and pathogenesis. | | 2000 | 10878114 |
| crystal structure of cystalysin from treponema denticola: a pyridoxal 5'-phosphate-dependent protein acting as a haemolytic enzyme. | cystalysin is a c(beta)-s(gamma) lyase from the oral pathogen treponema denticola catabolyzing l-cysteine to produce pyruvate, ammonia and h(2)s. with its ability to induce cell lysis, cystalysin represents a new class of pyridoxal 5'-phosphate (plp)-dependent virulence factors. the crystal structure of cystalysin was solved at 1.9 a resolution and revealed a folding and quaternary arrangement similar to aminotransferases. based on the active site architecture, a detailed catalytic mechanism is ... | 2000 | 10880431 |
| microbial comparison of smoker and non-smoker adult and early-onset periodontitis patients by polymerase chain reaction. | a number of bacterial species are involved in the aetiology of periodontitis and include actinobacillus actinomycetemcomitans, porphyromonas gingivalis, prevotella intermedia, bacteroides forsythus and treponema denticola. several studies have shown differences in the microflora between the various forms of periodontal disease. it is recognised that smoking is a risk factor for periodontal disease, but there are conflicting reports on whether or not smoking has an effect on the periodontal micro ... | 2000 | 10883871 |
| cloning and dna sequence analysis of an immunogenic glucose-galactose mglb lipoprotein homologue from brachyspira pilosicoli, the agent of colonic spirochetosis. | colonic spirochetosis (cs) is a newly emerging infectious disease of humans and animals caused by the pathogenic spirochete brachyspira (formerly serpulina) pilosicoli. the purpose of this study was to characterize an antigen that was recognized by antibodies present in sera of challenge-exposed pigs. the gene encoding the antigen was identified by screening a plasmid library of human b. pilosicoli strain sp16 (atcc 49776) genomic dna with hyperimmune and convalescent swine sera. the predicted a ... | 2000 | 10899855 |
| "checkerboard" assessments of periodontal microbiota and serum antibody responses: a case-control study. | we explored the association between subgingival microbial profiles and serum igg responses to periodontal microbiota in relation to clinical periodontal status. | 2000 | 10914791 |
| metabolic pathways for cytotoxic end product formation from glutamate- and aspartate-containing peptides by porphyromonas gingivalis. | metabolic pathways involved in the formation of cytotoxic end products by porphyromonas gingivalis were studied. the washed cells of p. gingivalis atcc 33277 utilized peptides but not single amino acids. since glutamate and aspartate moieties in the peptides were consumed most intensively, a dipeptide of glutamate or aspartate was then tested as a metabolic substrate of p. gingivalis. p. gingivalis cells metabolized glutamylglutamate to butyrate, propionate, acetate, and ammonia, and they metabo ... | 2000 | 10940008 |
| identification of periodontal disease-associated bacteria in the "plaque-free zone". | subgingival plaque bacteria live within a biofilm covered with glycocalyx, and little is known of the bacterial species associated with biofilm formation at the bottom of human periodontal pockets, the so-called "plaque-free zone"(pfz). | 2000 | 10972648 |
| prevalence of periodontal pathogens in localized and generalized forms of early-onset periodontitis. | the primary objectives of this study were to investigate the prevalence of 8 putative periodontal pathogens in subjects with early-onset periodontitis (eop) and to evaluate the microbial differences between localized and generalized forms of this periodontal disease condition. thirty-one females and 11 males with a mean age of 30.3 (s.d. 4.0) years were examined. seventeen subjects had generalized (geop) and 25 had localized early-onset periodontitis (leop). subgingival plaque samples were assay ... | 2000 | 10983884 |
| borrelia burgdorferi periplasmic flagella have both skeletal and motility functions. | bacterial shape usually is dictated by the peptidoglycan layer of the cell wall. in this paper, we show that the morphology of the lyme disease spirochete borrelia burgdorferi is the result of a complex interaction between the cell cylinder and the internal periplasmic flagella. b. burgdorferi has a bundle of 7-11 helically shaped periplasmic flagella attached at each end of the cell cylinder and has a flat-wave cell morphology. backward moving, propagating waves enable these bacteria to swim in ... | 2000 | 10995478 |
| the le1 bacteriophage replicates as a plasmid within leptospira biflexa: construction of an l. biflexa-escherichia coli shuttle vector. | we have discovered that le1, one of the plaque-forming phages previously described as lytic for the leptospira biflexa saprophytic spirochete (i. saint girons, d. margarita, p. amouriaux, and g. baranton, res. microbiol. 141:1131-1138, 1990), was indeed temperate. le1 was found to be unusual, as southern blot analysis indicated that it is one of the few phages to replicate in the prophage state as a circular plasmid. the unavailability of such small endogenous replicons has hindered genetic expe ... | 2000 | 11004167 |
| hemolytic and hemoxidative activities in mycoplasma penetrans. | mycoplasma penetrans is a newly isolated mollicute from the urine of patients infected with human immunodeficiency virus that demonstrates the capacity to adhere to and invade human cells. a previous report, based on assays with mouse red blood cells (rbcs), indicated that m. penetrans lacked hemolytic activity. in our studies, we incubated different isolates of m. penetrans with various rbc species and observed hemolytic zones surrounding individual mycoplasma colonies. all m. penetrans strains ... | 2000 | 11035754 |
| microbiological parameters associated with il-1 gene polymorphisms in periodontitis patients. | polymorphisms in the cluster of il-1 genes have been significantly associated with the severity of adult periodontitis. the purpose of this study was to compare microbiological parameters in il-1 genotype negative and positive adult subjects with a range of periodontitis severities. | 2000 | 11073323 |
| the spirochete flaa periplasmic flagellar sheath protein impacts flagellar helicity. | spirochete periplasmic flagella (pfs), including those from brachyspira (serpulina), spirochaeta, treponema, and leptospira spp., have a unique structure. in most spirochete species, the periplasmic flagellar filaments consist of a core of at least three proteins (flab1, flab2, and flab3) and a sheath protein (flaa). each of these proteins is encoded by a separate gene. using brachyspira hyodysenteriae as a model system for analyzing pf function by allelic exchange mutagenesis, we analyzed purif ... | 2000 | 11073915 |
| measurement of proteases in human subgingival dental plaque by fluorescence polarization. | fluorescence polarization (fp) was examined as a rapid quantitative method to assay the proteases in subgingival plaque. protease activity was measured by a decrease in fp at 0.5-min intervals over 5 min, using bodipy-alpha-casein, a protein substrate. to quantitate activity, the least absolute deviation (lad) slope for each assay was determined. protease activity increased with the quantity of plaque (r=0.416, p<0.001). of the 208 subgingival plaque samples, 87 contained detectable protease act ... | 2000 | 11084150 |
| intergeneric communication in dental plaque biofilms. | dental plaque is a complex biofilm that accretes in a series of discrete steps proceeding from a gram-positive streptococcus-rich biofilm to a structure rich in gram-negative anaerobes. this study investigated information flow between two unrelated plaque bacteria, streptococcus cristatus and porphyromonas gingivalis. a surface protein of s. cristatus caused repression of the p. gingivalis fimbrial gene (fima), as determined by a chromosomal fima promoter-lacz reporter construct and by reverse t ... | 2000 | 11092870 |
| anaerobic periodontal infections as risk factors for medical diseases. | advanced forms of periodontal disease are associated with the overgrowth of a limited number of gram-negative anaerobic species in plaques found in periodontal pockets. double-blind clinical trials of metronidazole and doxycycline, combined with debriding of the tooth surfaces, have significantly reduced the need for periodontal surgery. epidemiologic studies have indicated that untreated periodontal disease could be a risk factor for preterm delivery of low birth weight infants, coronary heart ... | 1999 | 11095764 |
| context-dependent anticodon recognition by class i lysyl-trna synthetases. | lysyl-trna synthesis is catalyzed by two unrelated families of aminoacyl-trna synthetases. in most bacteria and all eukarya, the known lysyl-trna synthetases (lysrss) are subclass iib-type aminoacyl-trna synthetases, whereas many archaea and a scattering of bacteria contain an unrelated class i-type lysrs. examination of the recognition of partially modified trna(lys) anticodon variants by a bacterial (from borrelia burgdorferi) and an archaeal (from methanococcus maripaludis) class i lysyl-trna ... | 2000 | 11121028 |
| the diversity of periodontal spirochetes by 16s rrna analysis. | the purpose of this study was to examine the diversity of spirochetes in the subgingival pocket of multiple subjects with a range of periodontal conditions, including two healthy, one adult periodontitis, three acute necrotizing ulcerative gingivitis, eight refractory periodontitis, and one human immunodeficiency virus (hiv) periodontitis. the 16s rrna genes of spirochetes in plaque were amplified by polymerase chain reaction using spirochete selective primers. over 500 clones were sequenced and ... | 2000 | 11154403 |
| analysis of gene expression in treponema denticola with differential display polymerase chain reaction. | treponema denticola is an oral spirochete associated with the periodontal diseases. a great deal of the molecular components of t. denticola will be learned soon since its genome sequence project is on the way. one of the most important works after genome sequence is to analyze the function of these genes and their regulation. however, like many other oral pathogens, there are currently a very limited number of molecular and genetic tools available to study gene expression in t. denticola. in th ... | 2000 | 11154421 |
| detection of treponema denticola in endodontic infections by 16s rrna gene-directed polymerase chain reaction. | a 16s rdna-based polymerase chain reaction (pcr) method was used to detect the occurrence of treponema denticola in root canal infections. samples were collected from 21 single-root teeth having carious lesions, necrotic pulps and radiographic evidences of periradicular bone loss. dna extracted from the samples was amplified using the pcr assay, which yielded specific fragment of t. denticola 16s rdna. t. denticola was detected in 11 of 21 cases (52.4%), regardless of the presence or absence of ... | 2000 | 11154427 |
| taxonomy and virulence of oral spirochetes. | all oral spirochetes are classified in the genus treponema. this genus is in the family spirochaetaceae as in bergey's manual of systematic bacteriology. other generic members of the family include spirochaeta, cristispira and borrelia. this conventional classification is in accord with phylogenetic analysis of the spirochetes based on 16s rrna cataloguing. the oral spirochetes fall naturally within the grouping of treponema. only four species of treponema have been cultivated and maintained rel ... | 2000 | 11155157 |
| coiling phagocytosis of borrelia burgdorferi by primary human macrophages is controlled by cdc42hs and rac1 and involves recruitment of wiskott-aldrich syndrome protein and arp2/3 complex. | lyme borreliosis is a multisystemic disorder primarily affecting the skin, nervous system, and joints. it is caused by the spirochete borrelia burgdorferi sensu lato and is transmitted via ticks of the ixodidae family. persistence of borreliae within macrophages has been implicated in the often chronic history of borreliosis. the uptake of b. burgdorferi by professional phagocytes occurs predominantly by coiling phagocytosis, a host cell-driven process in which single pseudopods wrap around and ... | 2001 | 11179351 |
| assessment of periradicular microbiota by dna-dna hybridization. | in the present study the "checkerboard" dna-dna hybridization technique was used to identify bacteria in periapical endodontic lesions of asymptomatic teeth. thirty-four patients with root-filled teeth and apical periodontitis were divided into two groups, each containing 17 patients. in group 1, a marginal incision was performed during surgery to expose the lesion, and in group 2, a submarginal incision was applied. the gingiva and mucosa were swabbed with an 0.2% chlorhexidine gluconate soluti ... | 2000 | 11202881 |
| comparison of profiles of key periodontal pathogens in periodontium and endodontium. | despite the established anatomical relationship between the periodontal and pulpal tissues, bacterial migration between endodontium and periodontium is still under discussion. the objective of this study was an investigation of profiles of periodontal pathogens in pulpal and periodontal diseases affecting the same tooth by means of 16s rrna gene directed polymerase chain reaction (pcr). 31 intact teeth with both pulp and marginal infections were investigated. the diagnosis was based on clinical ... | 2000 | 11202893 |
| the relationship between place bana reactivity and clinical parameters in subjects with mental disabilities. | the purpose of the present investigation was to determine whether subjects institutionalized with mental retardation have a relationship between periodontal clinical parameters and the presence of the bana-positive periodontal pathogens porphyromonas gingivalls, treponema denticola, and bacteroides forsythus in their subgingival plaques. fifty institutionalized subjects (25 patients with down syndrome and 25 subjects with mental retardation) were matched with respect to age and sex. periodontal ... | 2000 | 11203898 |
| cytoplasmic filament-deficient mutant of treponema denticola has pleiotropic defects. | in treponema denticola, a ribbon-like structure of cytoplasmic filaments spans the cytoplasm at all stages of the cell division process. insertional inactivation was used as a first step to determine the function of the cytoplasmic filaments. a suicide plasmid was constructed that contained part of cfpa and a nonpolar erythromycin resistance cassette (ermf and ermam) inserted near the beginning of the gene. the plasmid was electroporated into t. denticola, and double-crossover recombinants which ... | 2001 | 11208807 |
| significance of detection of porphyromonas gingivalis, bacteroides forsythus and treponema denticola in periodontal pockets. | the relationship between the detection of porphyromonas gingivalis, bacteroides forsythus and treponema denticola in subgingival plaque samples of periodontal pockets and periodontal status was evaluated using the polymerase chain reaction (pcr). a total of 165 sites in 60 periodontitis patients were examined, and the relationships between the detection of each of the three bacterial species and the pocket depth and bleeding on probing (bop) were analyzed. the detection ratios of p. gingivalis, ... | 2000 | 11212582 |
| oral chlamydia trachomatis in patients with established periodontitis. | periodontitis is considered a consequence of a pathogenic microbial infection at the periodontal site and host susceptibility factors. periodontal research supports the association of actinobacillus actinomycetemcomitans, porphyromonas gingivalis, prevotella intermedia, and bacteroides forsythus, and periodontitis; however, causality has not been demonstrated. in pursuit of the etiology of periodontitis, we hypothesized that the intracellular bacteria chlamydia trachomatis may play a role. as a ... | 2000 | 11218493 |
| detection of treponema denticola in atherosclerotic lesions. | we examined 26 atherosclerotic lesions and 14 nondiseased aorta specimens to detect the periodontopathogenic part of the bacterial 16s rrna locus by pcr. treponema denticola sequence of the 16s rrna locus was found in 6 out of 26 dna samples (23.1%) from the formalin-fixed, paraffin-embeded atherosclerotic lesions obtained during surgery but not in any of the 14 nondiseased aorta samples from deceased persons. utilizing immunofluorescence microscopy, we observed aggregated antigenic particles re ... | 2001 | 11230436 |
| detection of putative periodontal pathogens in non-insulin-dependent diabetes mellitus and non-diabetes mellitus by polymerase chain reaction. | it has been assumed that there is a relationship between periodontal diseases and diabetes mellitus, however the putative periodontal microorganisms in non-diabetes mellitus (non-dm) individuals and non-insulin-dependent diabetes mellitus (niddm) patients have not been well studied. in this study, the detection rates of 5 putative periodontal pathogens: actinobacillus actinomycetemcomitans, porphyromonas gingivalis, eikenella corrodens, treponema denticola, and candida albicans by polymerase cha ... | 2001 | 11246700 |
| borrelia burgdorferi and treponema pallidum: a comparison of functional genomics, environmental adaptations, and pathogenic mechanisms. | | 2001 | 11254661 |
| rapid detection and quantification of five periodontopathic bacteria by real-time pcr. | the quantity of periodontopathic bacteria in plaque samples is an important determinant for understanding the etiologic role of bacteria. the real-time pcr method was used to detect and quantify periodontopathic bacteria, such as actinobacillus actinomycetemcomitans, bacteroides forsythus, porphyromonas gingivalis, treponema denticola, and treponema socranskii, in saliva and subgingival plaque samples. there was good agreement between the results of conventional pcr and real-time pcr methods. us ... | 2001 | 11270605 |
| characterization of the yersinia pestis yfu abc inorganic iron transport system. | in yersinia pestis, the causative agent of plague, two inorganic iron transport systems have been partially characterized. the yersiniabactin (ybt) system is a siderophore-dependent transport system required for full virulence. yfe is an abc transport system that accumulates both iron and manganese. we have identified and cloned a y. pestis yfuabc operon. the yfuabc system is a member of the cluster of bacterial abc iron transporters that include sfu of serratia, hit of haemophilus, and yfu of y ... | 2001 | 11292695 |
| periodontal pathogens produce quorum sensing signal molecules. | different species of bacteria important in the composition of dental plaque were tested for production of extracellular autoinducer-like activities that stimulate the expression of the luminescence genes in vibrio harveyi. several strains of prevotella intermedia, fusobacterium nucleatum, and porphyromonas gingivalis were found to produce such activities. interestingly, these bacteria belong to the same phylogenetic group, and they are periodontal pathogens important in the development of period ... | 2001 | 11292769 |
| a spirochete surface protein uncouples store-operated calcium channels in fibroblasts: a novel cytotoxic mechanism. | the cytotoxicity of infectious agents can be mediated by disruption of calcium signaling in target cells. outer membrane proteins of the spirochete treponema denticola, a periodontal pathogen, inhibit agonist-induced ca(2+) release from internal stores in gingival fibroblasts, but the mechanism is not defined. we determined here that the major surface protein (msp) of t. denticola perturbs calcium signaling in human fibroblasts by uncoupling store-operated channels. msp localized in complexes on ... | 2001 | 11312269 |
| borrelia spirochetes upregulate release and activation of matrix metalloproteinase gelatinase b (mmp-9) and collagenase 1 (mmp-1) in human cells. | borrelia burgdorferi, the spirochetal agent of lyme disease, stimulated human peripheral blood monocytes to release pro-matrix metalloproteinase-9 (gelatinase b; pro-mmp-9) and active matrix metalloproteinase-1 (collagenase-1; mmp-1). human neutrophils also released pro-mmp-9 and a 130-kda protein with gelatinolytic activity in response to live b. burgdorferi. in addition, u937 cells and human keratinocyte cells were also stimulated to release pro-mmp-9 under the same conditions. however, human ... | 2001 | 11119537 |
| brachyspira (serpulina) hyodysenteriae gyrb mutants and interstrain transfer of coumermycin a(1) resistance. | to further develop genetic techniques for the enteropathogen brachyspira hyodysenteriae, the gyrb gene of this spirochete was isolated from a lambdazapii library of strain b204 genomic dna and sequenced. the putative protein encoded by this gene exhibited up to 55% amino acid sequence identity with gyrb proteins of various bacterial species, including other spirochetes. b. hyodysenteriae coumermycin a(1)-resistant (cn(r)) mutant strains, both spontaneous and uv induced, were isolated by plating ... | 2001 | 11319078 |
| insertional inactivation of the prtp gene of treponema denticola confirms dentilisin's disruption of epithelial junctions. | the purified chymotrypsin-like protease of treponema denticola, designated dentilisin or prtp (ddbj accession no. d83264), can disrupt cell-cell junctions and impair the barrier function of epithelial monolayers in vitro. serine protease inhibitors block these effects. yet, the protease is apparently less significant in perturbing intracellular signaling pathways and cytoskeletal rearrangement in fibroblasts. the purpose of this study was to use a prtp-deficient mutant of t. denticola to confirm ... | 2000 | 11075935 |
| relationship of periodontopathic bacteria with early-onset periodontitis in down's syndrome. | down's syndrome (ds) patients often develop severe early-onset marginal periodontitis in early adulthood; however, there is little information available on the microbiology of ds periodontitis. | 2001 | 11327065 |
| mgla and mglb of treponema denticola; similarity to abc transport and spa genes. | the mgla and mglb genes (td-mgla and td-mglb) of the oral spirochete treponema denticola were sequenced. these two t. denticola genes are highly homologous to the e. coli and treponema pallidum mgla and mglb genes which are part of the three gene beta-methylgalactoside transport operon, mglbac. both td-mgla and td-mglb are also homologous to the high affinity abc-type transporters for ribose and arabinose, and surface presentation antigens (spa) locus, part of the type iii secretion systems in e ... | 2000 | 11328650 |