Manjiro Noda

Fatty acid composition and lipid synthesis in developing safflower seeds

Abstract Linoleic acid predominated in every lipid class during the whole period of seed development of safflower, while linolenic acid decreased with increasing maturation and it was not detected in mature seeds. Just before the initiation of triacylglycerol accumulation, the fatty acid composition of triacylglycerols changed more rapidly than those of phospholipids and glycolipids. Saturated fatty acids tended to accumulate at the 1- and 3-positions of the glycerol molecule and the more highly unsaturated acids at the 2-position. The fatty acid compositions at the 1- and 3-positions were similar in all cases investigated, but in none of the triacylglycerols was the distribution completely symmetrical. The positional distribution of linolenic acid in triacylglycerols prepared from the immature seeds 2 days after flowering and from the leaves was unusual; in spite of its highest degree of unsaturation, it was preferentially esterified at the 1- and 3-positions. When triacylglycerol was most rapidly accumulated (14–18 days after flowering), the incorporation of acetate-[U- 14 C] into total lipids was also maximum and dienoic fatty acids were the principal acids labelled. Diacylglycerols and compound lipids reached the highest rate of synthesis 15 days after flowering, and then a maximum incorporation into triacylglycerol occurred 18 days after flowering. Incubation temperature affected the synthesis of individual lipid classes. Triacylglycerol was more rapidly synthesized at 32° than at 10°, while diacylglycerols and compound lipids were accumulated under the low-temperature condition. A rise of incubation temperature caused a depression in dienoic acid synthesis.

Some properties of diacylglycerol acyltransferase in a particulate fraction from maturing safflower seeds

Abstract The activity of diacylglycerol acyltransferase of a subcellular particulate fraction from maturing safflower seeds was remarkably stimulated by the addition of 1, 2-diacylglycerols which were previously emulsified in a gelatin solution by sonication. Metal ions were inhibitory to the reaction. Deoxycholate and diisopropyl fluorophosphate were the most effective inhibitors. Sulfhydryl groups seemed to be of limited significance in the enzyme. Both 1, 2-dioleoyl- sn -glycerol and 2, 3-dioleoyl- sn -glycerol were good substrates of diacylglycerol acyltransferase, but the 1, 3-isomer did not serve as an acyl acceptor. The enzyme showed broad specificity for synthetic rac -1, 2-diacylglycerols containing various fatty acids. However, rac -1, 2-diacetylglycerol and rac -1, 2-dibutyrylglycerol, which are soluble in water, were ineffective. The enzyme exhibited no significant specificity for saturated and unsaturated fatty acyl-CoA thioesters as acyl donors. This suggests that the fatty acid composition at the 3-position of the glycerol molecule of safflower triacylglycerols may depend on the composition of the endogenous acyl-CoA pool.

Triacylglycerol synthesis by subcellular fractions of maturing safflower seeds

Abstract A subcellular particulate fraction (103 g, precipitate) prepared from maturing safflower seeds catalysed triacylglycerol synthesis from oleoyl-CoA.

Sinapic acid and methyl sinapate in rapeseed lipids

1. 1. Two phenolic compounds have been isolated from rapeseed lipids by silicic acid column chromatography and thin-layer chromatography. 2. 2. They have been identified as sinapic acid (4-hydroxy-3,5-dimethoxycinnamicacid) and methyl sinapate from the results of spectrometric and chromatographic studies compared with the authentic samples.

Lipid synthesis in germinating safflower seeds and protoplasts

Abstract Galactolipids and phospholipids rapidly accumulated in a whole seed between 2 and 4 days after germination. However, the rate of incorporation of [14C] acetate into galactolipids was very low. The predominant fatty acid of galactolipids was linolenic acid, while those of phospholipids were linoleic and palmitic acids. Fatty acids of monogalactosyldiacylglycerol in germinating safflower seeds were randomly distributed between the 1 - and 2-positions of the glycerol molecule and the distribution in digalactosyldiacylglycerol was slightly non-random, while fatty acids of galactolipids in mature safflower leaves were non-randomly distributed. Triacylglycerol was synthesized in the cotyledon tissue of the germinating seeds simultaneously with its rapid degradation. In addition, lipid biosynthesis in protoplasts is described.

Lipids of Leaves and Seeds Part II:Chromatographic Separation of the Lipids in Rice Bran Lipoprotein

The lipids in rice bran lipoprotein were separated and their qualitative and quantitative analyses were carried out by column, thin-layer, gas-liquid, and paper chromatographic methods. More than twenty lipid components were detected, of which triglycerides and glycolipids were found to be the major components. Considerable amounts of free fatty acids were also found. The glycolipids were composed of mono- and digalactosyl glycerides, sterol glycosides and their esters, probably phytocerebrosides, and other unknown glycolipids. Phospholipids were present as the minor components of rice bran lipoprotein. The presence of oryzanols in the lipoprotein was observed.

Enzymic Hydrolysis of Soybean Phosphatidyl Inositol by Trimeresurus flavoviridis Venom and a Pancreatic Lipase Preparation

We have made an investigation on the specific liberation of fatty acids from the molecules of soybean phosphatidyl inositol by Trimeresurus flavoviridis venom and a pancreatic lipase preparation in order to utilize the reaction for the study of the fatty acid distribution in phosphatidyl inositols. Both the venom and a pancreatic lipase preparation liberated about one half of the total fatty acids in phosphetidyl inositol, leaving probably a lysophosphatidyl inositol which contained mostly saturated fatty acids, whereas the most part of the component unsaturated acids was found in the liberated acids. The formation of the other hydrolysis products by these enzymes is also discussed.