Nonmarine Crenarchaeol in Nevada Hot Springs
A. Pearson,1 Z. Huang,2 A. E. Ingalls,1l
C. S. Romanek,2 J. Wiegel,3 K. H. Freeman,4
R. H. Smittenberg,5 and C. L. Zhang2
Department of Earth and Planetary Sciences, Harvard University,1
and Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts
Institute of Technology,5 Cambridge, Massachusetts; Savannah
River Ecology Laboratory, University of Georgia, Aiken, South Carolina2;
Department of Microbiology, University of Geolgia, Athens, Geolgia3;
and Department of Geosciences, Pennsylvania State University, University
Park, Pennsylvania4
Received 5 February 2004/Accepted 23 April 2004
Glycerol dialkyl glycerol tetraethers (GDGTs) are core membrane lipjds
of the Crenarchaeota. The structurally unusual GDGT crenarchaeol has been
proposed as a taxonomically specific biomarker for the marine planktonic
group I archaea. It is found ubiquitously in the marine water column and
in sediments. In this work, samples of microbial community biomass were
obtained from several alkaline and neutral-pH hot springs in Nevada, United
States. Lipid extracts of these samples were analyzed by high-performance
liquid chromatog- raphy-mass spectrometry and by gas chromatography-mass
spectrometry. Each sample contained GDGTs, and among these compounds was
crenarchaeol. The distribution of archaeallipids in Nevada hot springs
did not appear to correlate with temperature, as has been observed in
the marine environment. Instead, a significant correlation with the concentration
of bicarbonate was observed. Archaeal DNA was analyzed by denaturing gradient
gel electrophoresis. All samples contained 168 rRNA gene sequences which
were more strongly related to thermophilic crenarchaeota than to Cenarchaeum
symbiosum, a marine nonthermophilic crenarchaeon. The occurrence of crenarchaeol
in environments containing sequences affiliated with thermophilic crenarchaeota
suggests a wide phenotypic distribution of this compound. The results
also indicate that crenarchaeol can no longer be considered an exclusive
biomarker for marine species.
SREL Reprint #2793
Pearson, A., Z. Huang, A. E. Ingalls, C. S. Romanek, J. Wiegel, K. H. Freeman, R. H. Smittenberg and C. L. Zhang. 2004. Nonmarine crenarchaeol in Nevada hot springs. Applied and Environmental Microbiology 70:5229-5237
