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Anders Johansson - One of the best experts on this subject based on the ideXlab platform.

Casey Chen - One of the best experts on this subject based on the ideXlab platform.

  • genomic integration and expression of the Aggregatibacter actinomycetemcomitans catalase gene in Aggregatibacter aphrophilus
    Archives of Oral Biology, 2018
    Co-Authors: Yuting Alice Yang, Yaan Cheng, Casey Chen
    Abstract:

    Abstract Objective To test the hypothesis that virulence genes of Aggregatibacter actinomycetemcomitans can be expressed and confer fitness advantages in the closely related Aggregatibacter aphrophilus. Design Clinical isolates of A. aphrophilus were screened for natural competence with marked genomic DNA from A. actinomycetemcomitans and A. aphrophilus. The gene katA of A. actinomycetemcomitans D7S-1 and its flanking regions were constructed and inserted into a comparable locus in the genome of a naturally competent A. aphrophilus strain by a markerless protocol via natural transformation. Mutants of A. actinomycetemcomitans with or without katA were also constructed by a similar protocol. Discs soaked with either 0.03% hydrogen peroxide or broth culture of Streptococcus gordonii Challis were placed on the agar with cultures of A. actinomycetemcomitans or A. aphrophilus. The size of the growth inhibition zone associated with the disc was measured after 2-day culture. Results Five of the 13 A. aphrophilus strains exhibited a transformation frequency of 10−6 or higher. The intra- and inter-species transformation frequencies were comparable. The inhibition zones for katA-negative strains of A. actinomycetemcomitans or A. aphrophilus were 3- to 7-fold larger than those associated with katA-positive strains (p  Conclusions There was no apparent species barrier for the transfer and expression of A. actinomycetemcomitans katA in A. aphrophilus. The inserted A. actinomycetemcomitans-specific katA gene in A. aphrophilus strain NJ8700 conferred resistance to inhibition by hydrogen peroxide or S. gordonii. The potential to swap genes between these two closely related oral species may be an alternative approach for investigating the virulence determinants of A. actinomycetemcomitans.

  • Identification of the Pangenome and Its Components in 14 Distinct Aggregatibacter actinomycetemcomitans Strains by Comparative Genomic Analysis
    PLOS ONE, 2011
    Co-Authors: Weerayuth Kittichotirat, Roger E. Bumgarner, Sirkka Asikainen, Casey Chen
    Abstract:

    Background Aggregatibacter actinomycetemcomitans is genetically heterogeneous and comprises distinct clonal lineages that may have different virulence potentials. However, limited information of the strain-to-strain genomic variations is available.

  • Genome Sequence of Naturally Competent Aggregatibacter actinomycetemcomitans Serotype a Strain D7S-1
    Journal of Bacteriology, 2010
    Co-Authors: Casey Chen, Weerayuth Kittichotirat, Weizhen Chen, Jennifer S. Downey, Roger E. Bumgarner
    Abstract:

    The major clonal lineages of the Gram-negative periodontal pathogen Aggregatibacter actinomycetemcomitans include serotype a, b, and c strains. Here, we report the draft genome sequence of a naturally competent serotype a strain, D7S-1, isolated from a patient with aggressive periodontitis.

  • Genome sequence of Aggregatibacter actinomycetemcomitans serotype c strain D11S-1
    Journal of Bacteriology, 2009
    Co-Authors: Casey Chen, Weerayuth Kittichotirat, Roger E. Bumgarner
    Abstract:

    Aggregatibacter actinomycetemcomitans is a major etiological agent of periodontitis. Here we report the complete genome sequence of serotype c strain D11S-1, which was recovered from the subgingival plaque of a patient diagnosed with generalized aggressive periodontitis.

  • il 1beta secretion induced by Aggregatibacter actinobacillus actinomycetemcomitans is mainly caused by the leukotoxin
    International Journal of Medical Microbiology, 2008
    Co-Authors: Peyman Kelk, Casey Chen, Rolf Claesson, Anders Sjöstedt, Anders Johansson
    Abstract:

    Aggregatibacter (Actinobacillus) actinomycetemcomitans forms a leukotoxin that selectively lyses primate neutrophils, monocytes and triggers apoptosis in promyeloic cells and degranulation of human ...

Kåre Buhlin - One of the best experts on this subject based on the ideXlab platform.

Paul J. Planet - One of the best experts on this subject based on the ideXlab platform.

  • complete genome sequence of Aggregatibacter haemophilus aphrophilus nj8700
    Journal of Bacteriology, 2009
    Co-Authors: Maria Pia Di Bonaventura, Rob Desalle, Mihai Pop, Niranjan Nagarajan, David H. Figurski, Daniel H. Fine, Jeffrey B. Kaplan, Paul J. Planet
    Abstract:

    Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus) (11) is well known as an etiologic agent in infectious endocarditis caused by gram-negative bacteria (7). Most often, however, it is found as a nonpathogenic, commensal resident of dental plaque and the oropharyngeal flora. The complete genome sequence of A. aphrophilus NJ8700 was achieved using a hybrid approach of a shotgun sequencing strategy combined with 454 pyrosequencing (two runs). The 454 sequences were assembled with the Newbler assembler (454 Life Sciences), and the Sanger reads were added to the resulting contigs using MUMmer (8) and custom scripts. The contigs were linked together into scaffolds using Bambus (15), and gaps between contigs were closed by direct sequencing using a technique described by N. Nagarajan et al. (submitted for publication), achieving a 25-fold coverage. Automated annotation was done at the Institute for Genomic Research/J. Craig Venter Institute through the Annotation Engine Service. The A. aphrophilus NJ8700 genome is 2,313,035 bp in length, with a GC content of 42.23% and 2,320 predicted coding sequences. Approximately 88.4% of nucleotides are predicted to encode proteins. The genome contains 57 tRNAs, including one gene for tRNASec (AAP_1961), and five rRNA nontandem cistrons. Like other Pasteurellaceae (3, 4), the genome has four RNA subunit genes (rpoA, rpoB, rpoC, and rpoZ; AAP_2188, AAP_1813, AAP_1812, and AAP_1427), and five sigma factor genes (AAP_1594, AAP_1967, AAP_2019, AAP_2021, and AAP_2324). The A. aphrophilus NJ8700 genome contains genes encoding a type VI secretion system (T6SS) (AAP_1851 to -1862, AAP_2123), which is the first instance of its presence in a member of the Pasteurellaceae (1, 2, 9, 10, 16, 17, 20). There are several open reading frames (ORFs) similar to vgrG (AAP_0259, AAP_0279 to -0281, AAP_0288, AAP_292, AAP_1540, AAP_1541, AAP_2121) that encode other possible substrates. The flp-tad cluster (AAP_0177 to -0190) is similar to the tad locus involved in the rough colony phenotype in Aggregatibacter actinomycetemcomitans (12, 13, 14, 21). Also present is a locus required for the assembly of type IVa pili, including pilF, pilA, pilB, pilC, and pilD (AAP_0008, AAP_1464 to -1467). The A. aphrophilus genome contains genes encoding several adhesins that may participate in host colonization (EmaA, AAP_0065; Aae, AAP_0152; YadA and Hia, AAP_0523 and AAP_0527). Genes for the production of PGA (poly-N-acetylglucosamine), i.e., hmsD, pgaC, pgaB, and pgaA (AAP_1678 to -1681); N-acetylneuraminate lyase (nanA, AAP_A0548); and the dspB enzyme that degrades PGA (AAP_0383 and AAP_0384), all implicated in biofilm formation, are present (6). A. aphrophilus NJ8700 has several loci implicated in iron utilization, including one for a predicted hemoglobin binding protein, hgpA (AAP_1269), and a hemoglobin/transferrin binding receptor (AAP_2099). Genes for the hemophore receptor HasR (AAP_1311) and a heme utilization protein (AAP_2308) are present. A gene for the TbpA (transferrin binding protein; AAP_1194, AAP_1226) may signal an ability to use transferrin. A. aphrophilus carries genes encoding potential siderophore receptors (AAP_0347, AAP_0905), a TonB-dependent hemoglobin/transferrin/lactoferrin family receptor (AAP_1145), and a receptor for ferrienterochelin/colicins (AAP_1677). Two ORFs may encode chelatin transporters (AAP_1146 to -1149; AAP_783 to -785), along with the ferric-dicitrate transport system (fecBCDE, AAP_1294 to-1297). The genome harbors the genes coding for the Fur regulator (AAP_0360) and periplasmic-binding transport systems: the afe locus (AAP_0393, AAP_0395 to -0397), the hit locus (AAP_1640, AAP_1644 to -1654), and afu loci (AAP_0695 to -0697, AAP_1193 to -1196) (5, 18, 19, 22). There are three regions of the bacterial chromosome where phage/prophage gene clusters were identified, including the accA-GMP gene intergenic region (acetyl coenzyme A carboxylase, AAP_0460; GMP synthase, AAP_0517), which harbors a prophage (M. Di Bonaventura et al., submitted for publication).

  • GENOME ANNOUNCEMENT Complete Genome Sequence of Aggregatibacter (Haemophilus)
    2009
    Co-Authors: Maria Pia, Di Bonaventura, Rob Desalle, Mihai Pop, Niranjan Nagarajan, David H. Figurski, Daniel H. Fine, Jeffrey B. Kaplan, Paul J. Planet
    Abstract:

    We report the finished and annotated genome sequence of Aggregatibacter aphrophilus strain NJ8700, a strain isolated from the oral flora of a healthy individual, and discuss characteristics that may affect its dual roles in human health and disease. This strain has a rough appearance, and its genome contains genes encoding a type VI secretion system and several factors that may participate in host colonization. Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus) (11) is well known as an etiologic agent in infectious endocarditis caused by gram-negative bacteria (7). Most often, however, it is found as a nonpathogenic, commensal resident of dental plaque and the oropharyngeal flora. The complete genome sequence of A. aphrophilus NJ8700 was achieved using a hybrid approach of a shotgun sequencing strategy combined with 454 pyrosequencing (two runs). The 454 sequences were assembled with the Newbler assembler (454 Life Sciences), and the Sanger reads were added to the resulting contigs using MUMmer (8) and custom scripts. The contigs were linke

Juha Sinisalo - One of the best experts on this subject based on the ideXlab platform.

  • Aggregatibacter actinomycetemcomitans serotypes associate with periodontal and coronary artery disease status.
    Journal of Clinical Periodontology, 2018
    Co-Authors: Milla Pietiäinen, Kåre Buhlin, K. A. Elisa Kopra, Juha Vuorenkoski, Aino Salminen, Susanna Paju, Päivi Mäntylä, John M. Liljestrand, Markku S. Nieminen, Juha Sinisalo
    Abstract:

    AIM We investigated the association between the Aggregatibacter actinomycetemcomitans serotypes, periodontal status and coronary artery disease (CAD). MATERIALS AND METHODS The study population included 497 patients who underwent coronary angiography, and clinical oral examination. Quantitative polymerase chain reaction assays were designed to identify the serotypes from saliva samples. RESULTS Aggregatibacter actinomycetemcomitans serotype frequencies were as follows: serotype "c" 35.7%, "b" 28.6%, "a" 26.2%, "e" 7.1%, "d" 2.4% and "f" 0%. The subjects with a detectable serotype had less teeth and higher bleeding on probing than those with no serotype. Serotypes "b" and "c" associated with periodontal probing depths and periodontal inflammatory burden. The saliva and subgingival bacterium quantities and serum antibody levels against A. actinomycetemcomitans were highest in patients harbouring serotype "c." Serotypes "b" and "c" were most frequent (59.3%) in patients with CAD (p = .040), and they associated with the risk of stable CAD with an odds ratio of 2.67 (95% confidence interval 1.06-7.44). Also, the severity of CAD (p = .018) associated with serotypes "b" and "c." CONCLUSIONS Aggregatibacter actinomycetemcomitans serotypes "b" and "c" associate with both periodontal and CAD status. Detectable serotypes associate with the quantity and the serology of the bacterium emphasizing both local and systemic effect of the A. actinomycetemcomitans serotypes.

  • subgingival Aggregatibacter actinomycetemcomitans associates with the risk of coronary artery disease
    Journal of Clinical Periodontology, 2013
    Co-Authors: Päivi Mäntylä, Kåre Buhlin, Susanna Paju, Markku S. Nieminen, Juha Sinisalo, Rutger G Persson, Pirkko J. Pussinen
    Abstract:

    Aim We investigated the association between angiographically verified coronary artery disease (CAD) and subgingival Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsy ...