Abstract Misfolded alpha-synuclein (AS) and other neurodegenerative disorder proteins display prion-like transmission of protein aggregation. Factors responsible for the initiation AS aggregation are unknown. To evaluate role amyloid made by microbiota we exposed aged rats transgenic C . elegans to E coli producing extracellular bacterial curli. Rats curli-producing bacteria displayed increased neuronal deposition in both gut brain enhanced microgliosis astrogliosis compared either mutant...

The leukotoxin of Actinobacillus actinomycetemcomitans has been implicated as a virulence determinant in various human infections and is encoded by multigene operon consisting four known genes, designated ltxC, ltxA, ltxB, ltxD. ltx appears to be present all A. strains, but levels toxin expression vary greatly among strains. Thus, gain better understanding the regulation operon, we have analyzed promoters highly toxic (JP2) minimally (652) strain actinomycetemcomitans. nucleotide sequence...

Active smokers and those exposed to secondhand smoke are at increased risk of bacterial infection. Tobacco exposure increases susceptibility respiratory tract infections, including tuberculosis, pneumonia Legionnaires disease; vaginosis sexually transmitted diseases, such as chlamydia gonorrhoea; Helicobacter pylori infection; periodontitis; meningitis; otitis media; post-surgical nosocomial infections. compromises the anti-bacterial function leukocytes, neutrophils, monocytes, T cells B...

Porphyromonas gingivalis is an aggressive periodontal pathogen that persists in the mixed-species plaque biofilm on tooth surfaces. P. cells attach to commensal Streptococcus gordonii and this coadhesion event leads development of biofilms. Binding these organisms multimodal, involving both major fimbrial FimA protein species-specific interaction minor Mfa1 with streptococcal SspB protein. This study examined contribution Mfa1–SspB formation. biofilms readily formed substrata S. DL1 but not...

We have previously shown that Actinobacillus actinomycetecomitans produces an immunosuppressive factor (ISF) capable of impairing human lymphocyte function by perturbing cell cycle progression. now report ISF is the product cdtB gene, one three genes encoding family cytolethal distending toxins (Cdt). The polypeptide exhibits >/=95% identity with Hemophilus ducreyi CdtB protein and </=60% homology Escherichia coli or Campylobacter jejuni CdtB. Pretreatment PHA-activated lymphocytes 5-25 ng...

Abstract Actinobacillus actinomycetemcomitans leukotoxin has been implicated as a virulence factor in human infections. To initiate delineation of structure/function relationships, molecular cloning the gene was carried out. When an A. genomic DNA library lambda EMBL3 screened using 1.3-kilobase pair restriction fragment containing portion gene, 13 positive recombinants were identified. One recombinant, designated OP8, 16-kilobase insert selected for detailed study. Lysates from but not...

Abstract Porphyromonas gingivalis is an oral/systemic pathogen implicated in chronic conditions, although the mechanism(s) whereby it resists immune defenses and persists host poorly understood. The virulence of this partially depends upon expression fimbriae comprising polymerized fimbrillin (FimA) associated with quantitatively minor proteins (FimCDE). In study, we show that isogenic mutants lacking FimCDE are dramatically less persistent virulent a mouse periodontitis model express...

ABSTRACT Porphyromonas gingivalis , one of the causative agents adult periodontitis, attaches and forms biofilms on substrata Streptococcus gordonii . Coadhesion biofilm development between these organisms requires interaction short fimbriae P. with SspB streptococcal surface polypeptide. In this study we investigated structure binding activities Electron microscopy showed that isolated have an average length 103 nm exhibit a helical pitch ca. 27 nm. Mfa1, major protein subunit fimbriae,...

The interaction of the minor fimbrial antigen (Mfa) with streptococcal I/II (e.g., SspB) facilitates colonization dental biofilm by Porphyromonas gingivalis. We previously showed that a 27-mer peptide derived from SspB (designated BAR) resembles nuclear receptor (NR) box protein-protein interacting domain and potently inhibits this in vitro. Here, we show EXXP motif upstream NR core α-helix contributes to Mfa-SspB BAR reduces P. gingivalis alveolar bone loss vivo murine model periodontitis....

ABSTRACT The cell density-dependent control of gene expression is employed by many bacteria for regulating a variety physiological functions, including the generation bioluminescence, sporulation, formation biofilms, and virulence factors. Although periodontal organisms do not appear to secrete acyl-homoserine lactone signals, several species, e.g., Porphyromonas gingivalis , Prevotella intermedia Fusobacterium nucleatum have recently been shown signal related autoinducer II (AI-2) system 2...

Colonization of oral tissues by Streptococcus sanguis may be influenced a mucin-like salivary glycoprotein (SAG) through calcium-dependent interaction with specific bacterial receptor. We report the nucleotide and deduced amino acid sequence S. receptor (SSP-5) show that this protein bind sialic residues SAG. The SSP-5 contains three unique structural domains, two which consist repetitive sequences. N-terminal domain is comprised four tandem copies an 82-residue repeat exhibits homology to M...

ABSTRACT The luxS gene of quorum-sensing Vibrio harveyi is required for type 2 autoinducer production. We identified a Porphyromonas gingivalis open reading frame encoding predicted peptide 161 aa that shares 29% identity with the amino acid sequence LuxS protein V. . Conditioned medium from late-log-phase P. culture induced luciferase operon , but insertional mutant did not. In expression mRNA was environmentally controlled and varied according to cell density osmolarity medium. addition,...

Summary The highly conserved antigen I/II family of polypeptides produced by oral streptococci are believed to be colonization determinants and may mediate adhesion bacterial cells salivary glycoproteins adsorbed tissues in the human cavity. Streptococcus gordonii is shown express, on cell surface, two designated SspA SspB (formerly Ssp‐5) that products tandemly arranged chromosomal genes. structure arrangement these genes similar independently isolated strains, DL1 M5, S. . mature...

ABSTRACT Autoinducer 2 (AI-2) is required for the growth of Aggregatibacter ( Actinobacillus ) actinomycetemcomitans in culture under conditions iron limitation. However, vivo this organism thrives a complex multispecies biofilm that forms human oral cavity. In report, we show adherent A. on saliva-coated surface, but not planktonic iron-replete conditions, defective LuxS-deficient background. Biofilm luxS mutant exhibited lower total biomass and depth than those wild-type strain. Normal was...

Smoking is responsible for the majority of periodontitis cases in US and smokers are more susceptible than non-smokers to infection by periodontal pathogen Porphyromonas gingivalis. P. gingivalis colonization oral cavity dependent upon its interaction with other plaque bacteria, including Streptococcus gordonii. Microarray analysis suggested that exposure cigarette smoke extract (CSE) increased expression major fimbrial antigen (FimA), but not minor (Mfa1). Therefore, we hypothesized CSE...

Abstract We have previously shown that Actinobacillus actinomycetemcomitans produces an immunosuppressive factor is encoded by the cdtB gene, which homologous to a family of cytolethal distending toxins (Cdt) expressed several Gram-negative bacteria. Moreover, we CdtB impairs lymphocyte function inducing G2 arrest cell cycle. now report both as well extract prepared from Escherichia coli strain expresses all three A. cdt genes (rCdtABC) induce apoptosis. Pretreatment lymphocytes with either...

The Actinobacillus actinomycetemcomitans population consists of a large number clones among which the ubiquitous leukotoxin gene operon appears very homogeneous. Population genetic analyses performed by multilocus enzyme electrophoresis together with DNA fingerprinting and genomic restriction fragment length polymorphisms (RFLP) on 97 strains isolated over period 45 years revealed that each serotypes a, b, c, d e comprise genetically subpopulations successful horizontal transfer between...

Interspecies binding is important in the colonization of oral cavity by bacteria. Streptococcus mutans can adhere to other plaque bacteria, such as sanguis and Actinomyces viscosus, this adherence enhanced saliva. The salivary bacterial molecules that mediate interaction were investigated. Salivary agglutinin, a mucinlike glycoprotein known aggregation many streptococci vitro, was found S. or A. viscosus. Adherence saliva- agglutinin-coated viscosus inhibited antibodies agglutinin receptor....

R ecent studies of the dental plaque bacteria associated with various forms early‐onset periodontitis confirm importance target periodontal pathogens such as Actinobacillus actinomycetemcomitans, Bacteroides forsythus, Prevotella intermedia , and Porphyromonas gingivalis in these diseases. A. actinomycetemcomitans strains exhibit a wide range variability leukotoxin production. By virtue unique promoter for ( ltx ) operon, highly leukotoxic (e.g., JP2) express 10‐ to 20‐times greater levels...

The leukotoxin produced by the oral bacterium Actinobacillus actinomycetemcomitans has been implicated in pathogenesis of juvenile periodontitis. In order to elucidate structure leukotoxin, molecular cloning gene was carried out. A DNA library A. actinomycetemcomitans, strain JP2, constructed partial digestion genomic with Sau3AI and ligation 0.5 5.0 kilobase pair fragments into Bam HI site plasmid vector pENN-vrf. After transformation E. coli RR1(λcI857), clones were screened for production...

Annexin V is a major component of matrix vesicles and has role in mediating the influx Ca2+ into these vesicles, thus promoting initiation hypertrophic cartilage mineralization. However, mechanisms factors regulating annexin V-mediated are not well understood. Since lipid composition differs from that plasma membrane chondrocytes rich phosphatidylserine, we asked whether may regulate function. We prepared liposomes containing different concentrations phosphatidylserine determined how...