title: Archaeal diversity in naturally occurring and impacted environments from a tropical region.
abstract: OBJECTIVE
  To evaluate archaeal diversity in natural and impacted habitats from Rio de Janeiro state, Brazil, a tropical region of South America.
  
  
  RESULTS
  16S rRNA gene was amplified directly by polymerase chain reaction (PCR) from genomic DNA, extracted from Guanabara Bay (GB) water, halomarine sediment (HS), municipal landfill leachate, agricultural soil and wastewater treatment (WT) system. Five archaeal 16S rDNA clone libraries were constructed. A total of 123 clones, within the five libraries analysed, were clustered into 29 operational taxonomic units, related to cultivated (24%) and uncultivated (76%) organisms. Rarefaction analysis showed that the libraries contained different levels of diversity. PCR-denaturing gradient gel electrophoresis (DGGE) of 16S-23S intergenic spacer regions confirmed the presence of a dominant phylotype, revealed by the WT system clone library.
  
  
  CONCLUSIONS
  Archaeal communities of impacted environments seem to be confined to specific ecosystems with similar physicochemical properties, while communities from natural environments appear to be widely distributed. The presence of a high number of phylotypes related to uncultivated organisms suggests new archaeal lineages.
  
  
  CONCLUSIONS
  This study reports, for the first time, the analysis of archaeal diversity in tropical environments from Brazil, and adds sequences from this region to the developing database of 16S rRNA clone libraries from environmental samples.
authors.affiliation: National Institute of Quality Control in Health, Department of Microbiology, FIOCRUZ, Rio de Janeiro, Brazil. maysa@incqs.fiocruz.br
authors.forename: M M
authors.initials: MM
authors.lastname: Clementino
authors.forename: C C
authors.initials: CC
authors.lastname: Fernandes
authors.forename: R P
authors.initials: RP
authors.lastname: Vieira
authors.forename: A M
authors.initials: AM
authors.lastname: Cardoso
authors.forename: C R
authors.initials: CR
authors.lastname: Polycarpo
authors.forename: O B
authors.initials: OB
authors.lastname: Martins
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D044822:Biodiversity; D001938:Brazil; D019641:DNA, Archaeal / Q000235:genetics; D017753:Ecosystem; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D015723:Gene Library; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D014329:Tropical Climate; D014866:Waste Products; D014871:Water Microbiology
chemical_list: D019641:DNA, Archaeal; D012336:RNA, Ribosomal, 16S; D014866:Waste Products