0000000000132878
AUTHOR
Karola Menzel
Fatty Acid Composition in the Lipids of some Marine Chiorococcales and Eustigmatales
Abstract The fatty acid composition in the lipids of six coccoid microalgae species (≈ 2 μm in diameter) was investigated. In addition to analyses of ultrastructure and pigment content, lipid composition is shown to be a chemotaxonomic tool in the classification of algae. The four species of Chiorococcales (Chlorophyceae) - the marine species as well as the fresh water species, both kept in artificial seawater - contain a fatty acid composition resembling that of Chlorella spp. and of green leaves of higher plants. The fatty acid pattern is characterized as lacking in C20 acids but containing large amounts of C 16 and C 18 polyunsaturated fatty acids, hexadecatrienic acid (16 :3) and a-lino…
A Comparative Ultrastructural Investigation of Some Nannochloris Species (Chlorococcales) with Particular Reference to the Systematic Position of Nanochlorum eucaryotum
Nanochlorum eucaryotum was described by Wilhelm et al. (1982) as a new algal species with an uncertain taxonomic position. Whereas some features were chlorococcacean, others suggested an isolated position in the sense of a “pre-eucaryote” (Wilhelm, 1983; Zahn, 1984; Geisert et al., 1987). Our comparative ultrastructural, physiological and biochemical examinations of coccoid microalgae (Menzel, 1988) gave no arguments for the separation of Nanochlorum eucaryotum from the genus Nannochloris. This paper is concerned with the ultrastructural composition of the cell wall and mode of reproduction in Nanochlorum eucaryotum as well as in three Nannochloris species. The systematic position of Nanoch…
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…