Abstract

Until recently, it has been difficult to conduct biosynthetic experiments on sponge metabolites with labelled precursors. We have now solved most of the technical problems associated with such work and intend to study in detail the biosynthesis of the many unusual types of sterol structures that have been encountered during the past decade in lower marine animals. The following biosynthetic pathways will be examined using radioactively labelled sterol precursors, which will be specially synthesized for these purposes: (a) mode of biosynthesis of highly alkylated sterol side chains resulting from triple and quadruple biomethylation; (b) biosynthesis of the many novel cyclopropyl-containing sterol side chains, which occur solely in marine organisms; (c) origin of the unique 24-nor-sterols and 27-norergostanes - a group of sterols in which the terminal methyl group of cholesterol is lost; (d) biosynthesis of cyclopropene-containing side chains - another unique structural feature of sponge sterols; (e) biosynthesis of 19-nor sterols - a group of sponge sterols which in terms of their nuclei resemble the currently used oral contraceptives; (f) extent of de novo biosynthesis of sterols in lower marine animals; (g) role of symbionts and other unicellular organisms in sterol biosynthesis using intact as well as cell-free systems.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM006840-31
Application #
3267919
Study Section
Bio-Organic and Natural Products Chemistry Study Section (BNP)
Project Start
1978-05-01
Project End
1991-04-30
Budget Start
1989-05-01
Budget End
1990-04-30
Support Year
31
Fiscal Year
1989
Total Cost
Indirect Cost

  Institution

Name
Stanford University
Department
Type
Schools of Arts and Sciences
DUNS #
800771545
City
Stanford
State
CA
Country
United States
Zip Code
94305

  Publications

Chennubhotla, Chakra; Bahar, Ivet (2007) Signal propagation in proteins and relation to equilibrium fluctuations. PLoS Comput Biol 3:1716-26
Garson, M J; Zimmermann, M P; Battershill, C N et al. (1994) The distribution of brominated long-chain fatty acids in sponge and symbiont cell types from the tropical marine sponge Amphimedon terpenensis. Lipids 29:509-16
Garson, M J; Zimmermann, M P; Hoberg, M et al. (1993) Isolation of brominated long-chain fatty acids from the phospholipids of the tropical marine sponge Amphimedon terpenensis. Lipids 28:1011-4
Makarieva, T N; Stonik, V A; Kapustina, I I et al. (1993) Biosynthetic studies of marine lipids. 42. Biosynthesis of steroid and triterpenoid metabolites in the sea cucumber Eupentacta fraudatrix. Steroids 58:508-17
Giner, J L; Djerassi, C (1992) Biosynthetic studies of marine lipids. 40. Generation of the cyclopropane ring of sormosterol. Acta Chem Scand 46:678-9
Silva, C J; Djerassi, C (1992) Biosynthetic studies of marine lipids 36. The origin of common sterol side chains in eleven sponges using [3-3H]-squalene. Comp Biochem Physiol B 101:255-68
Giner, J L; Djerassi, C (1992) Minor and trace sterols in marine invertebrates 65. 23-Epidihydrocalysterol: a new cyclopropane-containing sponge sterol. Steroids 57:258-61
Silva, C J; Wunsche, L; Djerassi, C (1991) Biosynthetic studies of marine lipids. 35. The demonstration of de novo sterol biosynthesis in sponges using radiolabeled isoprenoid precursors. Comp Biochem Physiol B 99:763-73
Lam, W K; Beatty, M F; Hahn, S et al. (1991) Metabolism of unusual membrane phospholipids in the marine sponge Microciona prolifera. Biochemistry 30:372-7
Giner, J L; Djerassi, C (1990) Inhibition and substrate specificity of yeast delta 22-desaturase. Biochem Biophys Res Commun 173:60-6

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