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Archaea
Volume 2012 (2012), Article ID 832097, 9 pages
http://dx.doi.org/10.1155/2012/832097
Research Article

Novel Cardiolipins from Uncultured Methane-Metabolizing Archaea

Organic Geochemistry Group, MARUM—Center for Marine Environmental Sciences & Department of Geosciences, University of Bremen, 28359 Bremen, Germany

Received 23 December 2011; Accepted 28 February 2012

Academic Editor: Angela Corcelli

Copyright © 2012 Marcos Y. Yoshinaga et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Novel cardiolipins from Archaea were detected by screening the intact polar lipid (IPL) composition of microbial communities associated with methane seepage in deep-sea sediments from the Pakistan margin by high-performance liquid chromatography electrospray ionization mass spectrometry. A series of tentatively identified cardiolipin analogues (dimeric phospholipids or bisphosphatidylglycerol, BPG) represented 0.5% to 5% of total archaeal IPLs. These molecules are similar to the recently described cardiolipin analogues with four phytanyl chains from extreme halophilic archaea. It is worth noting that cardiolipin analogues from the seep archaeal communities are composed of four isoprenoidal chains, which may contain differences in chain length (20 and 25 carbon atoms) and degrees of unsaturation and the presence of a hydroxyl group. Two novel diether lipids, structurally related to the BPGs, are described and interpreted as degradation products of archaeal cardiolipin analogues. Since archaeal communities in seep sediments are dominated by anaerobic methanotrophs, our observations have implications for characterizing structural components of archaeal membranes, in which BPGs are presumed to contribute to modulation of cell permeability properties. Whether BPGs facilitate interspecies interaction in syntrophic methanotrophic consortia remains to be tested.