Microbial sources of intact polar diacylglycerolipids in the Western North Atlantic Ocean

Kim Popendorf, Michael W. Lomas, Benjamin A S Van Mooy

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Intact polar membrane lipids are essential components of microbial membranes and recent work has uncovered a diversity of them occurring in the ocean. While it has long been understood that lipid composition varies across microbial groups, the microbial origins of the intact polar lipids in the surface ocean remain to be fully explained. This study focused on identifying the microbial sources of intact polar diacylglycerolipids (IP-DAGs) in the surface waters of the western North Atlantic Ocean. We used three approaches to define these microbial sources: (i) 13C tracing to identify photoautotrophic and heterotrophic production of the major classes of IP-DAGs, (ii) cell sorting flow cytometry of Prochlorococcus, Synechococcus and heterotrophic bacteria to determine IP-DAG composition and (iii) regrowth incubations targeting IP-DAG production by heterotrophic bacteria. Stable isotope tracing indicated that sulfoquinovosyldiacylglycerol (SQDG) and diacylglyceryl-trimethyl-homoserine (DGTS) were produced predominantly by photoautotrophs, while phosphatidylglycerol (PG) production was dominated by heterotrophic bacteria. Of the cells sorted with flow cytometry, Prochlorococcus and Synechococcus were found to have abundant glycolipids, while heterotrophic bacteria were dominated by phospholipids. The regrowth incubations showed that the growth of heterotrophic bacteria correlated with an increase in the concentration of PG, phosphatidylethanolamine (PE) and monoglycosyldiacylglycerol (MGDG). The finding of MGDG in heterotrophic bacteria differs from previous work, which had asserted that the membranes of heterotrophic bacteria in this environment were composed entirely of phospholipids. Overall, our findings indicate that phytoplankton are the primary source of SQDG and DGTS, while heterotrophic bacteria are the dominant source of PG, making these three compounds promising biomarkers for the study of microbes in the surface ocean.

Original languageEnglish (US)
Pages (from-to)803-811
Number of pages9
JournalOrganic Geochemistry
Volume42
Issue number7
DOIs
StatePublished - Aug 1 2011
Externally publishedYes

Fingerprint

Bacteria
bacterium
Phosphatidylglycerols
Homoserine
Flow cytometry
lipid
flow cytometry
regrowth
membrane
phospholipid
sea surface
Phospholipids
incubation
Membranes
Lipids
North Atlantic Ocean
Phytoplankton
Glycolipids
Biomarkers
Membrane Lipids

ASJC Scopus subject areas

  • Geochemistry and Petrology

Cite this

Microbial sources of intact polar diacylglycerolipids in the Western North Atlantic Ocean. / Popendorf, Kim; Lomas, Michael W.; Van Mooy, Benjamin A S.

In: Organic Geochemistry, Vol. 42, No. 7, 01.08.2011, p. 803-811.

Research output: Contribution to journalArticle

Popendorf, Kim ; Lomas, Michael W. ; Van Mooy, Benjamin A S. / Microbial sources of intact polar diacylglycerolipids in the Western North Atlantic Ocean. In: Organic Geochemistry. 2011 ; Vol. 42, No. 7. pp. 803-811.
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