0000000000274000
AUTHOR
Peter Beutelmann
An Uncommon Pathway in the Biosynthesis of Acetylenic Fatty Acids in Mosses
Although more than 600 acetylenic compounds of various structures have been found in plants [1], hardly anything is known about the formation of the triple bonds. The acetylenes so far known from Bryophytes, have been identified as long chain fatty acids with a characteristic arrangement of one triple bond and one to three double bonds.
Ligand requirement for LHC I reconstitution
Knowledge of the structure of photosynthetic light harvesting complexes is essential for understanding their function. Reconstitution of light harvesting complexes proved to be a very powerful tool for such structure analyses. In this way evidence was obtained for the central role of lutein and chlorophylls for LHCII structure (1) which was later confirmed by electron crystallographic analyses (2). Employing mutated, bacterial overexpressed LHCII apoproteins, amino acids could be identified which are involved in trimerization of LHCII and probably in binding of phosphatidylglycerol (3).
Untersuchungen zur Biosynthese eines Cytokinins in Calluszellen von Laubmoossporophyten
When callus cells derived from the sporogon of the hybrid Funaria hygrometrica x Physcomitrium piriforme are supplied with adenine-8-14C, they produce a labelled cytokinin which has the same chromatographic behavior as N6-γγ-(dimethylallyl)aminopurine. The cytokinin is the first radioactive product that can be detected in the culture medium. It is formed as long as labelled adenine is available. When callus cells are grown in an optimum culture medium containing amino acids, about 10% of the radioactivity supplied as adenine is found in the cytokinin. When the cells are grown in a medium without amino acids, the RNA-content of the cells and the total yield of cytokinin decrease, but about 1…
Moss cell cultures as sources of arachidonic and eicosapentaenoic acids
AbstractLipid classes from tissue cultures of the moss Leptobryum pyriforme (Hedw.) Wils. were analyzed. In the total lipid fraction, this species contained 20% arachidonic acid and about 7% eicosapentaenoic acid. The distribution of these fatty acids showed a preference for the phospholipid fraction. In particular, the phosphatidylethanolamine fraction was enriched in arachidonic acid. The arachidonic acid content of Leptobryum could be altered by transferring the cultures to different culture conditions. Mosses show high organic mass production in tissue cultures in relatively simple media. The great potential of using mosses as sources for the production of polyunsaturated fatty acids is…
Degradation of Acetylenic Triacylglyceroles and the Inactivation of Membrane Preparations from Moss Protonema Cells
Protonema cells of the moss Ceratodon purpureus accumulate triacylglycerols with two acetylenic fatty acids, 9,12-octadecadien-6-ynoic acid (18:2A) and 9,12,15-octadeca-trein-6-ynoic acid (18:3A), as main components. By following the incorporation of the [14C]-precursors acetate, linoleate, α-linolenate, γ-linolenate, stearidonate and 18:2A, into 18:3A in triacylglycerol accumulating cells, the pathway for acetylenic acids could be established. 18:2A and 18:3A could be synthesized by a second desaturation of the Δ6 double bond of γ-linolenate and stearidonate, respectively. However the major pathway for 18:3A synthesis was via a Δ15 desaturation of 18:2A. Since 18:2A was found exclusively i…
Identification of highly conserved genes: SNZ and SNO in the marine sponge Suberites domuncula: their gene structure and promoter activity in mammalian cells
Abstract Recently, we reported that cells from the sponge Suberites domuncula respond to ethylene with an increase in intracellular Ca 2+ level [Ca 2+ ] i , and with an upregulation of the expression of (at least) two genes, a Ca 2+ /calmodulin-dependent protein kinase and the potential ethylene-responsive gene, termed SDSNZERR (A. Krasko, H.C. Schroder, S. Perovic, R. Steffen, M. Kruse, W. Reichert, I.M. Muller, W.E.G. Muller, J. Biol. Chem. 274 (1999)). Here, we describe for the first time that also mammalian (3T3) cells respond to ethylene, generated by ethephon, with an immediate and transient, strong increase in [Ca 2+ ] i . Next, the promoter for the sponge SDSNZERR gene was isolated …
Distribution and chemotaxonomic significance of acetylenic fatty acids in mosses of the dicranales
Abstract Thirty-eight moss species from four families of the order Dicranales were analysed for the fatty acid composition of their acyl lipids. In the Ditrichaceae and the Dicranaceae numerous species were found to contain acetylenic fatty acids in their triglycerides, 9,12,15-Octadecatrien-6-ynoic acid was the major component, often accounting for more than 80 mol%, whereas 9,12-octadecadien-6-ynoic acid was found in small amounts of less than 5 mol%. In some genera, all the species examined contained acetylenic fatty acids, e.g. Dicranella and Dicranum , whereas in the genus Campylopus all five species tested were free of acetylenic compounds. Two genera, Ditrichum and Dicranoweisia , we…