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Title: Taxonomic status and ecologic function of methanogenic bacteria isolated from the oral cavity of humans

Thesis/Dissertation ·
OSTI ID:6648089

The detection of methane gas in samples of dental plaque and media inoculated with dental plaque was attributed to the presence of methane-producing bacteria in the plaque microbiota. The results of a taxonomic analysis of the 12 methanogenic isolates obtained from human dental plaque, (ABK1-ABK12), placed the organisms in the genus Methanobrevibacter. A DNA-DNA hybridization survey established three distinct genetic groups of oral methanogens based on percent homology values. The groups exhibited less than 32% homology between themselves and less than 17% homology with the three known members of the genus methanobrevibacter. The ecological role of the oral methanogens was established using mixed cultures of selected methanogenic isolates (ABK1, ABK4, ABK6, or ABK7) with oral heterotrophic bacteria. Binary cultures of either Streptococcus mutans, Streptococcus sanguis, Veillonella rodentium, Lactobacillus casei, or Peptostreptococcus anaerobius together with either methanogenic isolates ABK6 or ABK7 were grown to determine the effect of the methanogens on the distribution of carbon end products produced by the heterotrophs. Binary cultures of S. mutans and ABK7 exhibited a 27% decrease in lactic acid formation when compared to pure culture of S. mutans. The decrease in lactic acid production was attributed to the removal of formate by the methanogen, (ABK7), which caused an alteration in the distribution of carbon end products by S. mutans.

Research Organization:
George Washington Univ., Washington, DC (USA)
OSTI ID:
6648089
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English