Lipids in plant tissue cultures. IV. The characteristic patterns of lipid classes in callus cultures and suspension cultures

Biosynthesis of storage lipids in plant cell and embryo cultures

The biosynthesis of storage lipids in plant cell and embryo cultures is discussed in the light of their significance in the breeding of agriculturally important oil seed crops. After a short introduction to the biosynthesis of storage lipids, i.e. triacylglycerols and wax esters, this review covers the occurrence and biosynthesis of storage lipids in plant cell and embryo cultures. Plant cells in culture generally contain low levels of both unusual fatty acids and triacylglycerols indicating that these cells are quite different from cells of oil storage tissues. There are a few exceptions to this rule which demonstrate that induction of genes involved in the expression of fatty acid modification and triacylglycerol assembly is possible in plant cell cultures. Such biosynthetically active plant cells may be of particular interest in future studies of storage lipid assembly. Both somatic and gametophytic embryos of oil plants exhibit high capacities for storage lipid biosynthesis and accumulation in vitro compared to cultured plant cells. Above all, the microspore-derived embryo system is recommended to both plant breeders and plant biochemists for the selection and multiplication of plants of superior quality.

In vivo incorporation of [2-14C]mevalonic acid into rat brain complex glycolipids: characterization of glycosylsterols in mammalian brain

The in vivo incorporation of [2-14C]mevalonate into complex glycolipids of rat brain was investigated. Results indicated that the majority of the incorporated radioactivity was found to be in cholesterol. Analysis of neutral glycolipid and ganglioside fractions revealed that there were selected radioactive bands co-migrating to known glycolipids and gangliosides and the hydrolysis of which released the radioactive cholesterol. These results indicated the existence of glycosylsterols in the rat central nervous system.

Sterol conjugates of two phenotypically different calli of Beta vulgaris

Steryl glycosides are the predominant form of sterol at 88% of the total sterol in non-betalain producing calli of Beta vulgaris. The total sterol decreases and sterol form shifts from steryl glycosides to 97% free sterol upon the transition of non-betalain to betalain producing calli. A substantial decrease in stigmasterol (24α--ethylcholesta-5,22E-dien-3β-ol) and sitosterol (24α-ethylcholest-5-en-3β-ol) levels is observed during this transition, and alters the ratio of Δ(7):Δ(5) sterols. Spinasterol (24α- ethyl-5α-cholesta-7,22E-dien-3β-ol) is the dominant sterol at 43% and 95% of the total sterol in non-betalain producing and betalain producing calli. The level of 22-dihydrospinasterol (24α-ethyl-5α-cholest-7-en-3β-ol) is reduced in both calli to ≤ 3% from 25% in leaves. Lanosterol (4,4,14α-trimethyl-cholesta-8(9),24-dien-3β-ol) and cycloartenol (9β,19-cyclopropyl-4,4,14α-trimethyl-cholest-24-en-3β-ol) were identified in betalain and nonbetalain producing callus respectively.

Lipids, lipid turnover, and phospholipase D in plant suspension culture cells (Daucus carota)

The lipid pattern of Daucus carota L. suspension culture cells and other plant cell strains was analyzed. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, and triacylglycerol were the main components. The characteristic plastidal and mitochondrial lipids could also be identified. All strains tested exhibited a phospholipase D activity. Several lipid precursors were found to be well utilized by the cells and to be special markers for certain lipids or parts of the lipid molecules. The half life times of the major lipids ranged at about half a generation time of the cells.

Localisation and characterization of the fatty acid synthesizing system in cells of Glycine max (soubean) suspension cultures

In course of a study of fatty acid synthetase in higher plants, non-green cell suspension cultures of Glycine max (soybean) served as model tissues. For the first time, a fatty acid synthesizing system was characterized in cell cultures of higher plants and was found to be solely located in proplastids of the cells. Optimum activity of the fatty acid synthesizing system in proplastids was observed between pH 8.0 and 8.2; with [1-14C]acetate as substrate, cofactors required were CoA, ATP, Mn2+, Mg2+, HCO3-, NADH and NADPH. The system was more sensitive towards NADH than NADHP. [1-14C]Acetate,[2-14C]-malonate and [3-14C]pyruvate served as precursors for fatty acids, indicating the presence of pyruvate dehydrogenase activity in proplastids. In disrupted proplastids, [2-14C]malonylCoA was a better precursor than [1-14C]acetylCoA. After incubation of proplastids with [2-14C]malonate, a small shift, from palmitic acid to higher homologs, of label incorporated was observed, as compared to incorporation of label from [1-14C]acetate and [3-14C]pyruvate. Under the conditions of the experiment, only small amounts of polyunsaturated fatty acids, the main fatty acid components of this organelle, were synthesized. In respect to fatty acid synthesis, the non-green cell suspension culture resembles photosynthetic leaf tissue.