title: Diversity and quantitative analysis of Archaea in aggressive periodontitis and periodontally healthy subjects.
abstract: OBJECTIVE
  To investigate the diversity, levels and proportions of Archaea in the subgingival biofilm of generalized aggressive periodontitis (GAgP; n=30) and periodontally healthy (PH; n=30) subjects.
  
  
  METHODS
  Diversity was determined by sequencing archaeal 16S rRNA gene libraries from 20 samples (10/group). The levels and proportions of Archaea were analysed by quantitative PCR (qPCR) in four and two samples/subject in GAgP and PH groups, respectively.
  
  
  RESULTS
  Archaea were detected in 27/28 subjects and 68% of the sites of the GAgP group, and in 26/30 subjects and 58.3% sites of the PH group. Methanobrevibacter oralis was found in all 20 samples studied, Methanobacterium curvum/congolense in three GAgP and six PH samples, and Methanosarcina mazeii in four samples from each group. The levels and proportions of Archaea were higher in GAgP than in PH, whereas no differences were observed between the two probing depth category sites from the GAgP group.
  
  
  CONCLUSIONS
  Archaea were frequently found in subjects with periodontal health and GAgP, especially M. oralis. However, the higher levels and proportions (Archaea/total prokaryotes) of this domain observed in GAgP in comparison with PH subjects indicate a possible role of some of these microorganisms as an environmental modifier in GAgP.
authors.affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Flavia
authors.initials: F
authors.lastname: Matarazzo
authors.forename: Adriana Costa
authors.initials: AC
authors.lastname: Ribeiro
authors.forename: Magda
authors.initials: M
authors.lastname: Feres
authors.forename: Marcelo
authors.initials: M
authors.lastname: Faveri
authors.forename: Marcia Pinto Alves
authors.initials: MP
authors.lastname: Mayer
mesh_terms: D000328:Adult; D010520:Aggressive Periodontitis / Q000382:microbiology*; D001105:Archaea / Q000145:classification* / Q000302:isolation & purification; D018441:Biofilms; D015169:Colony Count, Microbial; D019641:DNA, Archaeal / Q000032:analysis; D003773:Dental Plaque / Q000382:microbiology; D005260:Female; D005884:Gingival Hemorrhage / Q000382:microbiology; D006801:Humans; D008297:Male; D017014:Methanobacterium / Q000145:classification / Q000302:isolation & purification; D041581:Methanobrevibacter / Q000145:classification / Q000302:isolation & purification; D017020:Methanosarcina / Q000145:classification / Q000302:isolation & purification; D019640:Methanosarcinales / Q000145:classification / Q000302:isolation & purification; D017622:Periodontal Attachment Loss / Q000382:microbiology; D010514:Periodontal Pocket / Q000382:microbiology; D010519:Periodontium / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000302:isolation & purification; D019642:RNA, Archaeal / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D055815:Young Adult
chemical_list: D019641:DNA, Archaeal; D019642:RNA, Archaeal; D012336:RNA, Ribosomal, 16S