Molecular level characterization of methyl sugars in marine high molecular weight dissolved organic matter
Repeta, Daniel J.
MetadataShow full item record
KeywordHigh molecular weight dissolved organic matter (HMWDOM); Acyl polysaccharides (APS); Methylated sugars; Heptoses; Anhydrosugars; 3,6 dideoxysugars; Chemical synthesis of methylated sugars; GC-MS
Dissolved organic matter (DOM) is the largest active organic carbon reservoir in the ocean (662 Gt C), a major fraction (> 95%) of which remains chemically uncharacterized. The concentration and isolation of DOM from seawater by ultrafiltration facilitates its chemical characterization by spectroscopic techniques. Using ultrafiltration, silver cation preparative chromatography and gas chromatography coupled with mass spectrometry (GC-MS), we identified 50 novel sugar compounds after hydrolysis of the high molecular weight dissolved organic matter fraction (HMWDOM; the fraction of DOM isolated after ultrafiltration). Sugars were identified by comparison of their mass spectra with those of chemically synthetized standards and with spectra previously described in the literature. Our results showed that mono- and di- methylated hexoses; mono- and di- methylated pentoses; mono- and di- methylated 6-deoxysugars, as well as heptoses, methylated heptoses, 3,6-dideoxysugars and 1,6 anhydrosugars (levoglucosan, mannosan, and galactosan) are components of HMWDOM, which may explain the low apparent yields of sugars recovered by molecular level (HPLC) analyses of HMWDOM after hydrolysis. From three depths spanning the surface (15 m) to bathypelagic (1800 m) ocean in the North Pacific near Hawaii our results showed that mono- and di- methylated hexoses were most abundant in the surface sample (64% of the total identified methylated sugarcompounds), while at 1800m monomethylated 6-deoxy sugars were the dominant sugars (42% of the total identified methylated sugar compounds). The high diversity of mono- and di- methylated hexoses in the surface sample most likely suggests an algal and/or bacterial source, while the high abundance of methylated 6-deoxy hexoses in the deep sample points toward an important bacterial contribution because the latter sugars are mostly found in bacterial lipopolysaccharides as well as highly degraded organic material.
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Chemistry 154 (2013): 34–45, doi:10.1016/j.marchem.2013.04.003.
Suggested CitationPreprint: Panagiotopoulos, Christos, Repeta, Daniel J., Mathieu, Laura, Rontani, Jean-Francois, Sempere, Richard, "Molecular level characterization of methyl sugars in marine high molecular weight dissolved organic matter", 2013-03-04, https://doi.org/10.1016/j.marchem.2013.04.003, https://hdl.handle.net/1912/6197
Showing items related by title, author, creator and subject.
Characterization of methyl sugars, 3-deoxysugars and methyl deoxysugars in marine high molecular weight dissolved organic matter Panagiotopoulos, Christos; Repeta, Daniel J.; Johnson, Carl G. (2007-01-16)Nuclear magnetic resonance spectroscopy of marine high molecular weight dissolved organic matter (HMWDOM) in surface waters show that >50% of the carbon is a compositionally well-defined family of acylated-polysaccharides ...
High molecular weight (HMW) dissolved organic matter (DOM) in seawater : chemical structure, sources and cycling Aluwihare, Lihini I. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1999-04)The goal of this thesis was to use high resolution analytical techniques coupled with molecular level analyses to chemically characterize high molecular weight (> 1 k Da (HMW)) dissolved organic matter (DOM) isolated ...
High molecular weight dissolved organic matter enrichment selects for methylotrophs in dilution to extinction cultures Sosa, Oscar A.; Gifford, Scott M.; Repeta, Daniel J.; DeLong, Edward F. (Nature Publishing Group, 2015-05-15)The role of bacterioplankton in the cycling of marine dissolved organic matter (DOM) is central to the carbon and energy balance in the ocean, yet there are few model organisms available to investigate the genes, metabolic ...