Previous Article | Next Article ![]()
J. Bacteriol., 01 1998, 366-376, Vol 180, No. 2
P Hugenholtz, C Pitulle, KL Hershberger and NR Pace
A culture-independent molecular phylogenetic survey was carried out for the
bacterial community in Obsidian Pool (OP), a Yellowstone National Park hot
spring previously shown to contain remarkable archaeal diversity (S. M.
Barns, R. E. Fundyga, M. W. Jeffries, and N. R. Page, Proc. Natl. Acad.
Sci. USA 91:1609-1613, 1994). Small-subunit rRNA genes (rDNA) were
amplified directly from OP sediment DNA by PCR with universally conserved
or Bacteria-specific rDNA primers and cloned. Unique rDNA types among >
300 clones were identified by restriction fragment length polymorphism, and
122 representative rDNA sequences were determined. These were found to
represent 54 distinct bacterial sequence types or clusters (> or = 98%
identity) of sequences. A majority (70%) of the sequence types were
affiliated with 14 previously recognized bacterial divisions (main phyla;
kingdoms); 30% were unaffiliated with recognized bacterial divisions. The
unaffiliated sequence types (represented by 38 sequences) nominally
comprise 12 novel, division level lineages termed candidate divisions.
Several OP sequences were nearly identical to those of cultivated
chemolithotrophic thermophiles, including the hydrogen-oxidizing
Calderobacterium and the sulfate reducers Thermodesulfovibrio and
Thermodesulfobacterium, or belonged to monophyletic assemblages recognized
for a particular type of metabolism, such as the hydrogen- oxidizing
Aquificales and the sulfate-reducing delta-Proteobacteria. The occurrence
of such organisms is consistent with the chemical composition of OP (high
in reduced iron and sulfur) and suggests a lithotrophic base for primary
productivity in this hot spring, through hydrogen oxidation and sulfate
reduction. Unexpectedly, no archaeal sequences were encountered in OP clone
libraries made with universal primers. Hybridization analysis of amplified
OP DNA with domain- specific probes confirmed that the analyzed community
rDNA from OP sediment was predominantly bacterial. These results expand
substantially our knowledge of the extent of bacterial diversity and call
into question the commonly held notion that Archaea dominate hydrothermal
environments. Finally, the currently known extent of division level
bacterial phylogenetic diversity is collated and summarized.
Copyright © 1998, American Society for Microbiology
Novel division level bacterial diversity in a Yellowstone hot spring [In Process Citation]
Department of Plant and Microbial Biology, University of California, Berkeley 94720-3102, USA.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»