Journal of Microbiology

Research Support, Non-U.S. Gov't

Diversity of Bacterial Community in Freshwater of Woopo Wetland: Keun Sik Baik , Seong Chan Park , Eun Mi Kim , Kyung Sook Bae , Jae-Hyung Ahn , Jong-Ok Ka , Jongsik Chun , Chi Nam Seong; J. Microbiol. 2008;46(6):647-655. Published online December 24, 2008; DOI: https://doi.org/10.1007/s12275-008-0135-x

Abstract: Diversity of bacterial community in water layer of Woopo wetland was investigated. Cultivable bacterial strains were isolated by the standard dilution plating technique and culture-independent 16S rRNA gene clones were obtained directly from DNA extracts of a water sample. Amplified rDNA restriction analysis (ARDRA) was applied onto both of the isolates and 16S rRNA gene clones. Rarefaction curves, coverage rate and diversity indices of ARDRA patterns were calculated. Representative isolates and clones of all the single isolate/clone phylotype were partially sequenced and analyzed phylogenetically. Sixty-four and 125 phylotypes were obtained from 203 bacterial isolates and 235 culture-independent 16S rRNA gene clones, respectively. Bacterial isolates were composed of 4 phyla, of which Firmicutes (49.8%) and Actinobacteria (32.0%) were predominant. Isolates were affiliated with 58 species. Culture-independent 16S rRNA gene clones were composed of 8 phyla, of which Proteobacteria (62.2%), Actinobacteria (15.5%), and Bacteroidetes (13.7%) were predominant. Diversity of 16S rRNA gene clones originated from cultivation-independent DNA extracts was higher than that of isolated bacteria.

Research Support, U.S. Gov't, Non-P.H.S.

A Novel Archaeal Group in the Phylum Crenarchaeota Found Unexpectedly in an Eukaryotic Survey in the Cariaco Basin: Sun-Ok Jeon , Tae-Seok Ahn , Sun-Hee Hong; J. Microbiol. 2008;46(1):34-39.; DOI: https://doi.org/10.1007/s12275-007-0247-8

Abstract: Archaea have been found in many more diverse habitats than previously believed due in part to modern molecular approaches to discovering microbial diversity. We report here an unexpected expansion of the habitat diversity of the Archaea in the Cariaco Basin we found using a primer set designed for 18S eukaryotic rDNA sequence analysis. The results presented here expand the originally identified 9 archaeal clones reported in this environment using bacterial/archaeal primers to 152 archaeal clones: 67 (18 OTU) of these clones were found at a depth of 900 m of station A while 71 (9 OTU) of them were at a depth of between 300~335 m of station B&C depending upon which location the samples were taken. We used three phylogenetic analysis methods and detected 20 phylotypes belonging to a single previously unreported group distantly related to the Crenarchaeota. Also, we determined that the original nine sequences did not fall into any of the known phyla of the Archaea suggesting that they may represent a novel group within the Kingdom Archaea. Thus, from these two studies, we suggest that Archaea in the Cariaco Basin could be unique; however, further studies using archaeal-specific primers and the design of new primers as well as the systematic use of several different primer combinations may improve the chances of understanding the archeal diversity in the Cariaco Basin.

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