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Actinomyces Naeslundii

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David Beighton – One of the best experts on this subject based on the ideXlab platform.

  • emended description of Actinomyces Naeslundii and descriptions of Actinomyces oris sp nov and Actinomyces johnsonii sp nov previously identified as Actinomyces Naeslundii genospecies 1 2 and wva 963
    International Journal of Systematic and Evolutionary Microbiology, 2009
    Co-Authors: Uta Henssge, Thuy Do, S C Gilbert, D T Clark, David R. Radford, David Beighton

    Abstract:

    Actinomyces Naeslundii is an important early colonizer in the oral biofilm and consists of three genospecies (1, 2 and WVA 963) which cannot be readily differentiated using conventional phenotypic testing or on the basis of 16S rRNA gene sequencing. We have investigated a representative collection of type and reference strains and clinical and oral isolates (n=115) and determined the partial gene sequences of six housekeeping genes (atpA, rpoB, pgi, metG, gltA and gyrA). These sequences identified the three genospecies and differentiated them from Actinomyces viscosus isolated from rodents. The partial sequences of atpA and metG gave best separation of the three genospecies. A. Naeslundii genospecies 1 and 2 formed two distinct clusters, well separated from both genospecies WVA 963 and A. viscosus. Analysis of the same genes in other oral Actinomyces species (Actinomyces gerencseriae, A. israelii, A. meyeri, A. odontolyticus and A. georgiae) indicated that, when sequence data were obtained, these species each exhibited <90 % similarity with the A. Naeslundii genospecies. Based on these data, we propose the name Actinomyces oris sp. nov. (type strain ATCC 27044T =CCUG 34288T) for A. Naeslundii genospecies 2 and Actinomyces johnsonii sp. nov. (type strain ATCC 49338T =CCUG 34287T) for A. Naeslundii genospecies WVA 963. A. Naeslundii genospecies 1 should remain as A. Naeslundii sensu stricto, with the type strain ATCC 12104T =NCTC 10301T =CCUG 2238T.

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  • Emended description of Actinomyces Naeslundii and descriptions of Actinomyces oris sp. nov. and Actinomyces johnsonii sp. nov., previously identified as Actinomyces Naeslundii genospecies 1, 2 and WVA 963
    International Journal of Systematic and Evolutionary Microbiology, 2009
    Co-Authors: Uta Henssge, Thuy Do, S C Gilbert, D T Clark, David R. Radford, David Beighton

    Abstract:

    Actinomyces Naeslundii is an important early colonizer in the oral biofilm and consists of three genospecies (1, 2 and WVA 963) which cannot be readily differentiated using conventional phenotypic testing or on the basis of 16S rRNA gene sequencing. We have investigated a representative collection of type and reference strains and clinical and oral isolates (n=115) and determined the partial gene sequences of six housekeeping genes (atpA, rpoB, pgi, metG, gltA and gyrA). These sequences identified the three genospecies and differentiated them from Actinomyces viscosus isolated from rodents. The partial sequences of atpA and metG gave best separation of the three genospecies. A. Naeslundii genospecies 1 and 2 formed two distinct clusters, well separated from both genospecies WVA 963 and A. viscosus. Analysis of the same genes in other oral Actinomyces species (Actinomyces gerencseriae, A. israelii, A. meyeri, A. odontolyticus and A. georgiae) indicated that, when sequence data were obtained, these species each exhibited

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  • evidence for recombination between a sialidase nanh of Actinomyces Naeslundii and Actinomyces oris previously named Actinomyces Naeslundii genospecies 1 and 2
    Fems Microbiology Letters, 2008
    Co-Authors: Uta Henssge, S C Gilbert, D T Clark, David Beighton

    Abstract:

    Actinomyces spp., predominant members of human oral biofilms, may use extracellular sialidase to promote adhesion, deglycosylate immunoglobulins and liberation of nutrients. Partial nanH gene sequences (1,077 bp) from Actinomyces oris (n=74), Actinomyces Naeslundii (n=30), Actinomyces viscosus (n=1) and Actinomyces johnsonii (n=2) which included the active-site region and the bacterial neuraminidase repeats (BNRs) were compared. The sequences were aligned and each species formed a distinct cluster with five isolates having intermediate positions. These five isolates (two A. oris and three A. Naeslundii) exhibited interspecies recombination. The nonsynonymous/synonymous ratio was <1 for both A. oris and A. Naeslundii indicating that nanH in both species is under stabilizing selective pressure; nonsynonymous mutations are not selected. However, for A. oris significant negative values in tests for neutral selection suggested the rate of mutation in A. oris was greater than in A. Naeslundii but with selection against nonsynonymous mutations. This was supported by the observation that the frequency of polymorphic sites in A. oris, which were monomorphic in A. Naeslundii was significantly greater than the frequency of polymorphic sites in A. Naeslundii which were monomorphic in A. oris (chi(2)=7.011; P=0.00081). The higher proportions of A. oris in the oral biofilm might be explained by the higher mutation rate facilitating an increased ability to respond successfully to environmental stress.

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Uta Henssge – One of the best experts on this subject based on the ideXlab platform.

  • Emended description of Actinomyces Naeslundii and descriptions of Actinomyces oris sp. nov. and Actinomyces johnsonii sp. nov., previously identified as Actinomyces Naeslundii genospecies 1, 2 and WVA 963
    International Journal of Systematic and Evolutionary Microbiology, 2009
    Co-Authors: Uta Henssge, Thuy Do, S C Gilbert, D T Clark, David R. Radford, David Beighton

    Abstract:

    Actinomyces Naeslundii is an important early colonizer in the oral biofilm and consists of three genospecies (1, 2 and WVA 963) which cannot be readily differentiated using conventional phenotypic testing or on the basis of 16S rRNA gene sequencing. We have investigated a representative collection of type and reference strains and clinical and oral isolates (n=115) and determined the partial gene sequences of six housekeeping genes (atpA, rpoB, pgi, metG, gltA and gyrA). These sequences identified the three genospecies and differentiated them from Actinomyces viscosus isolated from rodents. The partial sequences of atpA and metG gave best separation of the three genospecies. A. Naeslundii genospecies 1 and 2 formed two distinct clusters, well separated from both genospecies WVA 963 and A. viscosus. Analysis of the same genes in other oral Actinomyces species (Actinomyces gerencseriae, A. israelii, A. meyeri, A. odontolyticus and A. georgiae) indicated that, when sequence data were obtained, these species each exhibited

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  • emended description of Actinomyces Naeslundii and descriptions of Actinomyces oris sp nov and Actinomyces johnsonii sp nov previously identified as Actinomyces Naeslundii genospecies 1 2 and wva 963
    International Journal of Systematic and Evolutionary Microbiology, 2009
    Co-Authors: Uta Henssge, Thuy Do, S C Gilbert, D T Clark, David R. Radford, David Beighton

    Abstract:

    Actinomyces Naeslundii is an important early colonizer in the oral biofilm and consists of three genospecies (1, 2 and WVA 963) which cannot be readily differentiated using conventional phenotypic testing or on the basis of 16S rRNA gene sequencing. We have investigated a representative collection of type and reference strains and clinical and oral isolates (n=115) and determined the partial gene sequences of six housekeeping genes (atpA, rpoB, pgi, metG, gltA and gyrA). These sequences identified the three genospecies and differentiated them from Actinomyces viscosus isolated from rodents. The partial sequences of atpA and metG gave best separation of the three genospecies. A. Naeslundii genospecies 1 and 2 formed two distinct clusters, well separated from both genospecies WVA 963 and A. viscosus. Analysis of the same genes in other oral Actinomyces species (Actinomyces gerencseriae, A. israelii, A. meyeri, A. odontolyticus and A. georgiae) indicated that, when sequence data were obtained, these species each exhibited <90 % similarity with the A. Naeslundii genospecies. Based on these data, we propose the name Actinomyces oris sp. nov. (type strain ATCC 27044T =CCUG 34288T) for A. Naeslundii genospecies 2 and Actinomyces johnsonii sp. nov. (type strain ATCC 49338T =CCUG 34287T) for A. Naeslundii genospecies WVA 963. A. Naeslundii genospecies 1 should remain as A. Naeslundii sensu stricto, with the type strain ATCC 12104T =NCTC 10301T =CCUG 2238T.

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  • evidence for recombination between a sialidase nanh of Actinomyces Naeslundii and Actinomyces oris previously named Actinomyces Naeslundii genospecies 1 and 2
    Fems Microbiology Letters, 2008
    Co-Authors: Uta Henssge, S C Gilbert, D T Clark, David Beighton

    Abstract:

    Actinomyces spp., predominant members of human oral biofilms, may use extracellular sialidase to promote adhesion, deglycosylate immunoglobulins and liberation of nutrients. Partial nanH gene sequences (1,077 bp) from Actinomyces oris (n=74), Actinomyces Naeslundii (n=30), Actinomyces viscosus (n=1) and Actinomyces johnsonii (n=2) which included the active-site region and the bacterial neuraminidase repeats (BNRs) were compared. The sequences were aligned and each species formed a distinct cluster with five isolates having intermediate positions. These five isolates (two A. oris and three A. Naeslundii) exhibited interspecies recombination. The nonsynonymous/synonymous ratio was <1 for both A. oris and A. Naeslundii indicating that nanH in both species is under stabilizing selective pressure; nonsynonymous mutations are not selected. However, for A. oris significant negative values in tests for neutral selection suggested the rate of mutation in A. oris was greater than in A. Naeslundii but with selection against nonsynonymous mutations. This was supported by the observation that the frequency of polymorphic sites in A. oris, which were monomorphic in A. Naeslundii was significantly greater than the frequency of polymorphic sites in A. Naeslundii which were monomorphic in A. oris (chi(2)=7.011; P=0.00081). The higher proportions of A. oris in the oral biofilm might be explained by the higher mutation rate facilitating an increased ability to respond successfully to environmental stress.

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P A Ragsdale – One of the best experts on this subject based on the ideXlab platform.

  • identification of a gene involved in assembly of Actinomyces Naeslundii t14v type 2 fimbriae
    Infection and Immunity, 1998
    Co-Authors: Maria K Yeung, John O Cisar, Jacob A Donkersloot, P A Ragsdale

    Abstract:

    The nucleotide sequence of the Actinomyces Naeslundii T14V type 2 fimbrial structural subunit gene, fimA, and the 3′ flanking DNA region was determined. The fimA gene encoded a 535-amino-acid precursor subunit protein (FimA) which included both N-terminal leader and C-terminal cell wall sorting sequences. A second gene, designated orf365, that encoded a 365-amino-acid protein which contained a putative transmembrane segment was identified immediately 3′ to fimA. Mutants in which either fimA or orf365 was replaced with a kanamycin resistance gene did not participate in type 2 fimbriae-mediated coaggregation with Streptococcus oralis 34. Type 2 fimbrial antigen was not detected in cell extracts of the fimA mutant by Western blotting with anti-A. Naeslundii type 2 fimbrial antibody, but the subunit protein was detected in extracts of the orf365 mutant. The subunit protein detected in this mutant also was immunostained by an antibody raised against a synthetic peptide representing the C-terminal 20 amino acid residues of the predicted FimA. The antipeptide antibody reacted with FimA isolated from the recombinant Escherichia coli clone containing fimA but did not react with purified type 2 fimbriae in extracts of the wild-type strain. These results indicate that synthesis of type 2 fimbriae in A. Naeslundii T14V may involve posttranslational cleavage of both the N-terminal and C-terminal peptides of the precursor subunit and also the expression of orf365.

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