Publications

potential pathogenic mechanisms of periodontitis associated pregnancy complications.	during normal pregnancy, maternal hormones and locally acting cytokines play a key role in regulating the onset of labor, cervical ripening, uterine contraction, and delivery. maternal infections during pregnancy have been demonstrated to perturb this normal cytokine and hormone-regulated gestation, sometimes resulting in preterm labor, preterm premature rupture of membranes, and preterm low birth weight (plbw), i.e., < 2,500 g and < 37 weeks of gestation. our research focus has been to determin ...	1998	9722707
early-onset periodontitis associated with down's syndrome--clinical interventional study.	individuals with down's syndrome (ds) have an increased prevalence of periodontal disease compared with otherwise normal, age-matched control groups and other mentally handicapped patients of similar age distribution. the exaggerated immune-inflammatory response of the tissues cannot be explained by poor oral hygiene alone and might be the result of an impaired cell-mediated and humoral immunity and a deficient phagocytic system. as far as the progression and severity of destruction, the oral ma ...	1998	9722720
molecular and biotechnological aspects of microbial proteases.	proteases represent the class of enzymes which occupy a pivotal position with respect to their physiological roles as well as their commercial applications. they perform both degradative and synthetic functions. since they are physiologically necessary for living organisms, proteases occur ubiquitously in a wide diversity of sources such as plants, animals, and microorganisms. microbes are an attractive source of proteases owing to the limited space required for their cultivation and their ready ...	1998	9729602
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
oxygen metabolism by treponema denticola.	treponema denticola strains atcc 35405 and aslm were found to have moderately active oxygen metabolism and consumed some 0.46 mumol o2/h/mg cell protein in anaerobic growth medium or about ten times this amount in aerobic medium. there appeared to be no differences between the two strains in their oxidative metabolism. the spirochetes showed significant endogenous o2 utilization, which was stimulated only slightly by added glucose or arginine, moderately by glycine, but markedly by casamino acid ...	1999	10204483
detection of spirochetes by polymerase chain reaction and its relation to the course of digital dermatitis after local antibiotic treatment in dairy cattle.	the aim of the study was to monitor the course of digital dermatitis after local antibiotic treatment in an experimental group (treated on diagnosis) and a control group (treated 5 days later). the present study was carried out on 2 farms involving 18 animals. monitoring was performed by means of clinical findings and detection of spirochetes on the surface of the lesions, using a polymerase chain reaction. superficial wound smears were taken before and after treatment. twelve animals on both fa ...	1999	10216454
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
activation of neutrophil collagenase in periodontitis.	neutrophil collagenase (matrix metalloproteinase 8 [mmp-8]) is an important mediator of tissue destruction in inflammatory diseases. studies of anaerobic periodontal infections have shown that active mmp-8 in gingival crevicular fluid is associated with the degradation of periodontal tissues in progressive periodontitis whereas the latent enzyme is predominant in gingivitis. since the activation of mmp-8 appears to be a crucial step in periodontitis, we have examined the activation of mmp-8 in g ...	1999	10225890
molecular characterization of a chemotaxis operon in the oral spirochete, treponema denticola.	a chemotaxis gene cluster from treponema denticola (td), a pathogenic spirochete associated with human periodontal diseases, was cloned, sequenced, and analyzed. the gene cluster contained three chemotaxis (che) genes (chea, chew, and chey) and an open reading frame (chex) that is homologous with treponema pallidum (tp) and borrelia burgdorferi (bb) chex. the td che genes have the same transcriptional orientation with a sigma 70-like promoter located upstream of chea and a stem-loop structure ch ...	1999	10333522
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
c-telopeptide pyridinoline cross-links. sensitive indicators of periodontal tissue destruction.	c-telopeptides and related pyridinoline cross-links of bone type i collagen are sensitive markers of bone resorption in osteolytic diseases such as osteoporosis and osteoarthritis. we have studied the release of c-telopeptide pyridinoline crosslinks of type i collagen as measures of bone destruction in periodontal disease. studies in preclinical animal models and humans have demonstrated the relationship between radiographic bone loss and crevicular fluid c-telopeptide levels. we have recently f ...	1999	10415744
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
studies on the binding of treponema pectinovorum to hep-2 epithelial cells.	we developed a radioassay to assess the adherence of the oral treponemes treponema denticola and treponema pectinovorum to live hep-2 epithelial cells. t. pectinovorum bound firmly to the epithelial cell monolayer in a concentration-dependent manner. the results indicated that a subpopulation of t. pectinovorum appeared to bind and that the binding could be influenced by environmental factors. increasing concentrations of fetal bovine serum inhibited binding, whereas t. pectinovorum membrane ves ...	1999	10495710
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
hemoxidation and binding of the 46-kda cystalysin of treponema denticola leads to a cysteine-dependent hemolysis of human erythrocytes.	cystalysin, a 46-kda protein isolated from the cytosol of treponema denticola, was capable of both cysteine dependent hemoxidation and hemolysis of human and sheep red blood cells. the activities were characteristic of a cysteine desulfhydrase. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and western immunoblotting analysis of the interaction of cystalysin with the red blood cells revealed an interaction of the protein with the red blood cell membrane. substrates for the ...	1999	10551156
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
multiple forms of the major phenylalanine specific protease in treponema denticola.	the 160, 190 and 270 kda outer sheath proteases of treponema denticola atcc 35404 were found to be multiple forms of the major 91 kda phenylalanine protease (pap) by immunoblotting using anti-91 kda specific antibodies. multiple forms of the phenylalanine protease were also found in 2 other t. denticola strains studied, atcc 33520 and the clinical isolate gm-1. protein, proteolytic and western blot analyses using antibodies against the pap and the major outer sheath protein (msp) indicated that ...	1999	10567950
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
nomenclature for macrolide and macrolide-lincosamide-streptogramin b resistance determinants.		1999	10582867
molecular pathogenesis of the cell surface proteins and lipids from treponema denticola.	treponema denticola, frequently isolated from the human oral cavity, is thought to be a major pathogen of human periodontal disease. recent developments in molecular analysis have clarified the surface structure of this microorganism and the characteristics of its pathogenic factors. structural analysis of the outer sheath showed t. denticola to have a new type of outer membrane lipid. limited exposure of the major outer sheath protein is suggested by electron-microscopic analysis. a protease-de ...	1999	10585538
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
perturbation and exploitation of host cell cytoskeleton by periodontal pathogens.	some periodontal pathogens disrupt epithelial barriers and cellular adhesion to the extracellular matrix, which affects the cytoskeleton. porphyromonas gingivalis and actinobacillus actinomycetemcomitans exploit the cytoskeleton during their uptake by epithelial cells. treponema denticola perturbs actin and actin-regulating pathways in host cells. cytoskeletal dysfunction due to pathogenic bacteria may impair physiologic remodeling and wound repair in the periodontium.	1999	10611739
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
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
epithelial cell response to challenge of bacterial lipoteichoic acids and lipopolysaccharides in vitro.	accumulating dental plaque at the gingival margin contains lipoteichoic acids (ltas) from the cell walls of gram-positive bacteria. in subgingival plaque associated with periodontal disease the amount of lipopolysaccharides (lpss) from gram-negative bacteria increases. as the gingival junctional epithelium (je) is an important structural and functional tissue, participating in the first line defence against apical advancement of dental plaque, this study examined the direct effects of ltas (from ...	2000	10707944
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
adherence of periodontopathic bacteria to bioabsorbable and non-absorbable barrier membranes in vitro.	guided tissue regeneration (gtr) techniques are increasingly used for the treatment of periodontal defects, or in conjunction with dental implant procedures. as adhesion of bacteria to barrier membranes used in these techniques may lead to failure, a prerequisite for treatment success is an infection-free healing process. the present study examined the adhesion of 3 periodontal pathogenic bacteria: actinobacillus actinomycetemcomitans, treponema denticola and porphyromonas gingivalis, to 3 barri ...	1999	10740453
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
rgpa-kgp peptide-based immunogens provide protection against porphyromonas gingivalis challenge in a murine lesion model.	porphyromonas gingivalis, a gram-negative bacterium, has been linked to the onset and progression of periodontitis, a chronic inflammatory disease of the supporting tissues of the teeth. a major virulence factor of p. gingivalis is an extracellular complex of arg- and lys-specific proteinases and adhesins designated the rgpa-kgp complex (formerly the prtr-prtk complex). in this study we show that the rgpa-kgp complex, when used as an immunogen with incomplete freund adjuvant (ifa), protects agai ...	2000	10858222
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
factors affecting the formation of spherical bodies in the spirochete treponema denticola.	the oral spirochete treponema denticola typically is a helically shaped, motile bacterial cell. however, morphological variations of t. denticola cells in the form of "spherical bodies" are sometimes seen. little is known about the environmental factors that cause their formation. the effects of oxygen, growth temperature, nutrient depletion and the addition of metabolic end-products were tested to determine their role in the morphogenesis of the spherical bodies. it was found that the age of th ...	1999	10895696
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
molecular characterization of the gyrb region of the oral spirochete, treponema denticola.	the nucleotide (nt) sequence of the treponema denticola (td) dna gyrase beta-subunit gene (gyrb) has been determined. southern blot analysis of td chromosomal dna indicated that gyrb is present as a single copy. approximately 3.2kb of the nt sequence 5' and 0.7kb of nucleotide sequence 3' of gyrb were obtained. analysis of the deduced amino acid (aa) sequence revealed two complete open reading frames (orfs) (orf1 and orf3) and a truncated orf (orf4'). orf1 has no homology to sequences in the dat ...	2000	10940564
cytokine responses to treponema pectinovorum and treponema denticola in human gingival fibroblasts.	human gingival fibroblasts were challenged with treponema pectinovorum and treponema denticola to test three specific hypotheses: (i) these treponemes induce different cytokine profiles from the fibroblasts, (ii) differences in cytokine profiles are observed after challenge with live versus killed treponemes, and (iii) differences in cytokine profiles are noted from different gingival fibroblast cell lines when challenged with these treponemes. three normal gingival fibroblast cell cultures were ...	2000	10948156
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
the effect of repeated professional supragingival plaque removal on the composition of the supra- and subgingival microbiota.	the purpose of the present investigation was to determine the effect of weekly professionally administered supragingival plaque removal on the composition of the supra and subgingival microbiota.	2000	10983597
comparison of the microbiota of supra- and subgingival plaque in health and periodontitis.	the purpose of the present investigation was to compare the microbial composition of supra and subgingival plaque in 22 periodontally healthy (mean age 32+/-16 years) and 23 adult periodontitis subjects (mean age 51+/-14 years).	2000	10983598
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
metabolic engineering of an aerobic sulfate reduction pathway and its application to precipitation of cadmium on the cell surface.	the conversion of sulfate to an excess of free sulfide requires stringent reductive conditions. dissimilatory sulfate reduction is used in nature by sulfate-reducing bacteria for respiration and results in the conversion of sulfate to sulfide. however, this dissimilatory sulfate reduction pathway is inhibited by oxygen and is thus limited to anaerobic environments. as an alternative, we have metabolically engineered a novel aerobic sulfate reduction pathway for the secretion of sulfides. the ass ...	2000	11010904
systemic diseases caused by oral infection.	recently, it has been recognized that oral infection, especially periodontitis, may affect the course and pathogenesis of a number of systemic diseases, such as cardiovascular disease, bacterial pneumonia, diabetes mellitus, and low birth weight. the purpose of this review is to evaluate the current status of oral infections, especially periodontitis, as a causal factor for systemic diseases. three mechanisms or pathways linking oral infections to secondary systemic effects have been proposed: ( ...	2000	11023956
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
antibiotic selective markers and spirochete genetics.	until very recently, the pathogenic spirochetes have been refractory to genetic manipulation. this has been due, in part, to difficulties with in vitro growth and the genetic distance that spirochetes are from typical gram-negative and gram-positive organisms. insertional mutagenesis and other genetic techniques are now possible in some of the pathogenic spirochetes such as borrelia burgdorferi, brachyspira (serpulina) hyodysenteriae, leptospira sp., and treponema denticola. however, organisms s ...	2000	11075914
dna exchange and insertional inactivation in spirochetes.	spirochetes have complex life cycles and are associated with a number of diseases in humans and animals. despite their significance as pathogens, spirochete genetics are in their early stages. however, gene inactivation has been achieved in borrelia burgdorferi, brachyspira hyodysenteriae, and treponema denticola. here, we review methods that have been used in spirochetes for gene inactivation and dna exchange, with a primary focus on b. burgdorferi. we also describe factors influencing electrot ...	2000	11075915