2026-09-19T23:46:40Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/597572022-01-14T19:12:15Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Roger E. Summons.
Sáenz, James Peter
Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.
Joint Program in Chemical Oceanography
Woods Hole Oceanographic Institution
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
2010-10-29T18:32:02Z
2010-10-29T18:32:02Z
2010
2010
http://hdl.handle.net/1721.1/59757
670446768
Thesis (Ph. D.)--Joint Program in Chemical Oceanography (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references.
Lipids have a legacy in the geologic record extending back to the Archaean. Since the phylogenetic diversity of life is reflected in the structural diversity of biomolecules, lipid biomarkers that are shown to be diagnostic of certain organisms that carry out specific biochemical processes or that are demonstrated to have unique physiological roles can be used to trace the biogeochemical influence of bacteria in modern and ancient environments. In this thesis I explore the application of two classes of bacterial membrane lipids as biomarkers for marine biogeochemical processes in marine environments: ladderanes and hopanoids. Through the detection of ladderane lipids - biomarkers for anaerobic ammonium oxidizing (anammox) bacteria - I demonstrate the presence and distribution of anammox bacteria in a subterranean estuary. Through a survey of hopanoids in marine environments and cultured marine cyanobacteria I show that hopanoids are ubiquitous in the oceans and that their presence in ancient marine sediments could provide information about biogeochemical processes in past environments. Based on novel results demonstrating that hopanoids are resistant to extraction by non-ionic detergent, I propose that they may play a role in lipid ordering and the formation of putative lipid rafts in hopanoid-producing bacteria.
by James Peter Sáenz.
Ph.D.
249 p.
eng
Massachusetts Institute of Technology
M.I.T. theses are protected by
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http://dspace.mit.edu/handle/1721.1/7582
Joint Program in Chemical Oceanography.
Earth, Atmospheric, and Planetary Sciences.
Exploring the distribution and physiological roles of bacterial membrane lipids in the marine environment
Thesis
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<Abstract>Lipids have a legacy in the geologic record extending back to the Archaean. Since the phylogenetic diversity of life is reflected in the structural diversity of biomolecules, lipid biomarkers that are shown to be diagnostic of certain organisms that carry out specific biochemical processes or that are demonstrated to have unique physiological roles can be used to trace the biogeochemical influence of bacteria in modern and ancient environments. In this thesis I explore the application of two classes of bacterial membrane lipids as biomarkers for marine biogeochemical processes in marine environments: ladderanes and hopanoids. Through the detection of ladderane lipids - biomarkers for anaerobic ammonium oxidizing (anammox) bacteria - I demonstrate the presence and distribution of anammox bacteria in a subterranean estuary. Through a survey of hopanoids in marine environments and cultured marine cyanobacteria I show that hopanoids are ubiquitous in the oceans and that their presence in ancient marine sediments could provide information about biogeochemical processes in past environments. Based on novel results demonstrating that hopanoids are resistant to extraction by non-ionic detergent, I propose that they may play a role in lipid ordering and the formation of putative lipid rafts in hopanoid-producing bacteria.</Abstract>
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