Membrane lipids of mesophilic anaerobic bacteria thriving in peats have typical archaeal traits

Authors

  • Johan W. H. Weijers,

    Corresponding author
    1. Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, 1790 AB Den Burg – Texel, the Netherlands.
      *E-mail jweijers@nioz.nl; Tel. (+31) 222 369567; Fax (+31) 222 319674.
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  • Stefan Schouten,

    1. Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, 1790 AB Den Burg – Texel, the Netherlands.
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  • Ellen C. Hopmans,

    1. Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, 1790 AB Den Burg – Texel, the Netherlands.
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  • Jan A. J. Geenevasen,

    1. University of Amsterdam, van ’t Hoff Institute for Molecular Sciences, Nieuwe Achtergracht 129, 1018 WS Amsterdam, the Netherlands.
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  • Olivier R. P. David,

    1. University of Amsterdam, van ’t Hoff Institute for Molecular Sciences, Nieuwe Achtergracht 129, 1018 WS Amsterdam, the Netherlands.
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  • Joanna M. Coleman,

    1. University of Bristol, Organic Geochemistry Unit, Cantock's Close, BS8 1TS Bristol, UK.
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  • Rich D. Pancost,

    1. University of Bristol, Organic Geochemistry Unit, Cantock's Close, BS8 1TS Bristol, UK.
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  • Jaap S. Sinninghe Damsté

    1. Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, 1790 AB Den Burg – Texel, the Netherlands.
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*E-mail jweijers@nioz.nl; Tel. (+31) 222 369567; Fax (+31) 222 319674.

Summary

The 16S ribosomal DNA based distinction between the bacterial and archaeal domains of life is strongly supported by the membrane lipid composition of the two domains; Bacteria generally contain dialkyl glycerol diester lipids, whereas Archaea produce isoprenoid dialkyl glycerol diether and membrane-spanning glycerol dialkyl glycerol tetraether (GDGT) lipids. Here we show that a new group of ecologically abundant membrane-spanning GDGT lipids, containing branched instead of isoprenoid carbon skeletons, are of a bacterial origin. This was revealed by examining the stereochemistry of the glycerol moieties of those branched tetraether membrane lipids, which was found to be the bacterial 1,2-di-O-alkyl-sn-glycerol stereoconfiguration and not the 2,3-di-O-alkyl-sn-glycerol stereoconfiguration as in archaeal membrane lipids. In addition, unequivocal evidence for the presence of cyclopentyl moieties in these bacterial membrane lipids was obtained by NMR. The biochemical traits of biosynthesis of tetraether membrane lipids and the formation of cyclopentyl moieties through internal cyclization, which were thought to be specific for the archaeal lineage of descent, thus also occur in the bacterial domain of life.

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