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Genomic integration and expression of the Aggregatibacter actinomycetemcomitans catalase gene in Aggregatibacter aphrophilus |
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| Affiliation: | 1. Laboratorio Integrativo de Biomecánica y Fisiología del Esfuerzo (LIBFE), Escuela de Kinesiología, Facultad de Medicina, Universidad de los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile;2. Facultad de Odontología, Universidad de los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile;3. Laboratorio de Biomecánica, Kinesiología y Cineantropometría, Universidad Pablo de Olavide, Carretera de Utrera km 1, Seville, Spain;1. Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran;2. Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran;3. Laser Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran;1. Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile;2. Centro de Bioinformática y Simulación Molecular, Universidad de Talca, Talca, Chile;3. Facultad de Ciencia, Universidad San Sebastián, Santiago, Chile;1. Izmir Educational Dental Hospital, Sümer Mah. 451. Sok. No:2 PK:35260, Konak, Izmir, Turkey;2. Department of Orthodontics, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey;3. Department of Periodontology, Faculty of Dentistry, Süleyman Demirel University, Isparta, Turkey;4. Department of Biochemistry, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey;5. Department of Biochemistry, Faculty of Medicine, Istanbul Altinbas University, Mahmutbey Dilmenler Caddesi, No:26, 34217 Bağcılar, Istanbul, Turkey;1. Department of Biology, University of Pisa, Pisa, Italy;2. Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy;3. Department of Microbiology, University of Szeged, Hungary |
| Abstract: | ObjectiveTo test the hypothesis that virulence genes of Aggregatibacter actinomycetemcomitans can be expressed and confer fitness advantages in the closely related Aggregatibacter aphrophilus.DesignClinical 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.ResultsFive 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 < 0.05).ConclusionsThere 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. |
| Keywords: | Catalase Genomic islands Gene transfer Hydrogen peroxide Mutagenesis Virulence |
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