8 items with the tag “lipids

  • NAI Research Highlights

    Mineral Surfaces and Life

    November 20, 2006
  • Extra-Cellular Polymeric Substances as Armor Against Cell Membrane Rupture on Mineral Surfaces
    NAI 2009 University of Wisconsin Annual Report

    Our interdisciplinary project examined the hypotheses that bacterial cell membranes are ruptured in contact with specific mineral surfaces, and that biofilm-forming extra-cellular polymeric substances (EPS) may have evolved to shield against membrane rupture (cell lysis). Furthermore, we proposed that mineral reactivity towards membranolysis should depend on its surface properties such as charge, reactive area, or free radicals generated by radiation and impacts on early Earth, Mars, and other worlds. The effect of EPS on preservation in the rock record will also be examined. By understanding the mechanisms for membranolysis, especially under the extreme conditions of high radiation and heavy impacts during early planetary history, the project addresses the NASA Astrobiology Institute’s (NAI) Roadmap goals of understanding the origins of cellularity, the evolution of mechanisms for survival at environmental limits, and preservation of biosignatures, and NASA’s Strategic Goal of advancing scientific knowledge of the origin and evolution of the Earth’s biosphere and the potential for life elsewhere.

    ROADMAP OBJECTIVES: 3.4 5.1 7.1
  • Geochemical Signatures of Multicellular Life
    NAI 2009 Massachusetts Institute of Technology Annual Report

    Organic molecules preserved in rocks provide a geological record of past organisms and processes. These complement the record left by visible organisms and can often provide information on the, otherwise invisible, microbial world. This part of the project is designed to improve our knowledge of 'molecular biosignatures’ now and in times past. This part of the project also offers a window into the presence of complex life prior to the point at which animals became large enough, or hard enough, to leave a visible record.

    ROADMAP OBJECTIVES: 3.2 4.2
  • Geochemical Signatures of Multicellular Life
    NAI 2010 Massachusetts Institute of Technology Annual Report

    This project aims to identify geochemical fossils (biomarkers) in sediments that reflect the transition from microbial life forms to their multicellular animal descendants.

    ROADMAP OBJECTIVES: 3.2 4.2
  • Geochemical Signatures of Multicellular Life
    NAI 2011 Massachusetts Institute of Technology Annual Report

    We continued our studies of the sterol complements of basal metazoa and their closest unicellular relatives and discerned what appears to be an evolutionary trend toward the universal use of cholesterol by higher animals. Inverse carbon isotope patterns of lipids and kerogen, that are a distinctive characteristic of organic matter found in Neoproterozoic sediments, record heterogeneous primary biomass comprising a dominant input from bacteria.

    ROADMAP OBJECTIVES: 3.2 4.2