|Dungan, Robert - Rob|
Submitted to: MicrobiologyOpen
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2012
Publication Date: 6/12/2012
Citation: Kim, J., Makama, M., Petito, J., Park, N., Cohan, F.M., Dungan, R.S. 2012. Diversity of bacteria and archaea in hypersaline sediment from Death Valley National Park, California. MicrobiologyOpen. 1(2):135-148. Interpretive Summary: Hypersaline sediments, which have very high salt concentrations, are considered extreme environments. Microorganisms that live within these hypersaline sediments are also called halophiles. Halophiles contain unique systems that allow them to survive under such high salt concentrations. Many halophilic microorganisms are economically important and are used in industrial and biotechnological applications. The objective of this study was to use molecular biological techniques to characterize microorganisms in hypersaline sediment from Death Valley National Park. Overall, our results revealed that the hypersaline sediment contains many new and previously undescribed genera and species of halophiles. Halophiles from these sediments should be investigated further to explore their potential for use in industrial and biotechnological applications.
Technical Abstract: The objective of this study was to phylogenetically analyze microorganisms from the domains Bacteria and Archaea in hypersaline sediment from Death Valley National Park. Using domain-specific primers, a region of the 16S rRNA gene was amplified using PCR, and the product was subsequently used to create a clone library. A total of 243 bacterial clones, 99 archaeal clones, and 209 bacterial isolates were examined. The 243 clones from Bacteria were affiliated with the following groups: the Bacilli (59 clones) and Clostridia (1) of the Firmicutes, Bacteroidetes (90), Proteobacteria (27), Cyanobacteria (18), Gemmatimonadetes (41), candidate division OP1 (5), Actinobacteria (1), and the Deinococcus-Thermus division (1). Within the class Bacilli, 46 of 59 clones were tentatively identified as 10 unclassified species. The majority of bacterial isolates (130 of 209) were more closely related to the Bacillus subtilis-B. licheniformis clade than to any other recognized taxon, and an Ecotype Simulation analysis of B. subtilis relatives identified four previously unknown ecotypes. Several new genera were discovered within the Bacteroidetes (4) and the Gemmatimonadetes (2). Of the 99 Archaeal clones, 93 were tentatively identified as belonging to three new genera within the Halobacteriaceae; other clones represented novel species within each of four established genera.