Identification of unusual butanetriol dialkyl glycerol tetraether and pentanetriol dialkyl glycerol tetraether lipids in marine sediments. (27th December 2013)

• Record Type: Journal Article
• Authors: Zhu, Chun; Meador, Travis B.; Dummann, Wolf; Hinrichs, Kai‐Uwe
• Is Part Of: Rapid communications in mass spectrometry. Volume 28:Number 4(2014)
• Page Start: 332
• Page End: 338
• Publication Date: 2013-12-27
• Subjects: Mass spectrometry -- Periodicals; 543.65
• DOI: 10.1002/rcm.6792
• Languages: English
• ISSNs: 0951-4198

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="rcm6792-sec-0001" sec-type="section"> <title>RATIONALE</title> <p>Glycerol serves as the principal backbone moiety bound to various acyl/alkyl chains for membrane lipids of <italic>Eukarya</italic>, <italic>Bacteria</italic>, and <italic>Archaea</italic>. In this study, we report a suite of unusual tetraether lipids in which one of the two conventional glycerol backbones is substituted by butanetriol or pentanetriol.</p> </sec> <sec id="rcm6792-sec-0002" sec-type="section"> <title>METHODS</title> <p>Identification of these lipids was achieved via diagnostic fragments and their expected acetylation products using liquid chromatography/mass spectrometry (LC/MS), and their diagnostic ether cleavage products using gas chromatography/mass spectrometry (GC/MS).</p> </sec> <sec id="rcm6792-sec-0003" sec-type="section"> <title>RESULTS</title> <p>We observed structural variations in the polyol backbones and alkyl chains and term these core lipid derivatives: isoprenoidal butanetriol dialkyl glycerol tetraethers (iso‐BDGTs), isoprenoidal pentanetriol dialkyl glycerol tetraethers (iso‐PDGTs), and hybrid isoprenoidal/branched BDGTs and PDGTs (ib‐BDGTs, ib‐PDGTs). Of these, iso‐BDGTs were the most abundant with a methylation at either the <italic>sn</italic>‐1 or <italic>sn</italic>‐3 position of glycerol and were also found as part of intact polar lipids, adjoined to mono‐ or diglycosidic headgroups. Iso‐BDGTs and iso‐PDGTs are likely produced by <italic>Archaea</italic>, as indicated by the presence of the characteristic biphytanyl moieties.</p> </sec> <sec id="rcm6792-sec-0004" sec-type="section"> <title>CONCLUSIONS</title> <p>Butanetriol‐ and pentanetriol‐based tetraether lipids occur in modern estuarine and deeply buried subseafloor sediments, suggesting the presence of alternative backbones in archaeal lipids. Copyright © 2013 John Wiley & Sons, Ltd.</p> </sec> </abstract>