Fatty acid castor bean seeds

Ricinoleic acid (12-D-hydroxyoctadec-c/j-9-enoic acid) is the major fatty acid in castor bean seeds and is readily metabolized in germination. Partial breakdown by the normal /3-oxidation pathway would produce 6-hydroxy-... 

Different Fatty Acid Compositions of Embryo and Endosperm from Germinating Castor Bean Seeds"... 

M. Yamada and Q. Usami, Long chain fatty acid synthesis in developing castor bean seeds. IV. The synthetic system in protoplastids. Plant Cell Physiol. 16 879 (1975). 

Broun, P., and Somerville, C. 1997. Accumulation of ricinoleic, lesquerolic, and deni-polic acids in seeds of transgenic Arabidopsis plant that express a fatty acyl hydroxylase cDNA from castor bean. Plant Physiol., 113, 933-942. 

Ricinoleate (R) has many industrial uses. Its only commercial source is castor oil, in which ricinoleate constitutes 90% of the fatty acids (FA) (1). Castor beans contain toxic substances and are hazardous to grow, harvest, and process. Therefore, it is desirable to produce ricinoleate from a transgenic plant lacking these toxic substances. To develop a transgenic plant capable of producing a high level of ricinoleate in its seed oil, it is essential to understand the biosynthesis of castor oil. We previously established the biosynthetic pathway of castor oil and identified the key enzymatic steps of the pathway, which drive the ricinoleate into castor oil (2,3). We report here the identification and quantification of the molecular species of triacylglycerols (TAG, end products), phosphatidylcholines (PC, intermediate) and phosphatidylethanolamines (PE, intermediate) on the pathway incorporated from various [ C]-labeled FA and the comparison of the levels of their incorporation. 

Another factor stipulating the recent (speculative) price development of castor compared to other oil crops (such as soy bean, rape seed or palm oil - prices not shown) is castor oil s consistently high concentration of C18 fatty acid. This makes replacement with other oil crops difficult for existing industries based on this chemistry as there are no realistic crop alternatives. 

One class of such organelles is the glyoxysome which is prominent in a wide range of storage tissues, e.g. cotyledons of castor bean, water melon, peanut and cucumber and in pine seeds (Galliard, 1980). The glyoxysome contains all the enzymes of the -oxidation complex, together with the fatty acid... 

There is presumptive evidence that the proplastid and the ofl storage organelles differ in function. Thus, Yamada and his colleagues, as well as Simcox et al., have shown that proplastids isolated from developing castor bean endosperm synthesize only oleic acid. However, the major product of fatty acid synthesis in these seeds is triricinoleoylglycerol. Galliard and Stumpf (1966) have shown that the synthesis of ricinoleic acid involves a microsomal preparation (presumably endoplasmic reticulum) which hydroxylates oleoyl-... 

In most commercially important edible plant oils, the dominant fatty acids are oleic, linoleic and linolenic acids. Coconut oil is an exception in having the saturated 12 0 lauric acid as its major acid. Families of plants tend to produce characteristic oils that frequently contain unusual fatty acids. Examples are the erucic acid of rape-seed ricinoleic acid, the 18-carbon, monoenoic, hydroxy acid of the castor bean and vernolic acid, the 18-carbon, trienoic, epoxy acid of the Compositae. 

Ricinoleic acid (D-12-hydroxyoctadec-cis-9-enoic acid), is an hydroxylated fatty acid which constitutes 85-90% of the seed fatty acids in castor bean plants (Ricinus communis L). This unusual fatty acid is also one of a series of related Hydroxy Fatty Acids (HFAs) produced in the seeds of Lesquerella species. In these species, which, like A. thaliana and rapeseed belong to the Brassicacae family, ricinoleic acid is generally a minor constituent. Major HFAs include densipolic (12-OH, 18 2 (3,9)), lesquerolic (14-OH, 20 1 (9)) and auricolic (14-OH, 20 2 (3,9)) acids. 

Several tissues have been used to study the mechanism of fatty acid synthesis, particularly the avocado mesocarp, spinach and lettuce chloroplasts, and etiolated barley seedlings, but some major advances have been made from studies of maturing oil-bearing seeds, e.g. castor bean (in which 90% of the fatty acid content is ricinoleic acid) and safflower, Carthamus tine tor ius (76% linoleic and 1% oleic). Oleic acid plays a central role in plant fatty acid anabolism as the precursor of the major unsaturated fatty acids, e.g. it is the first detectable fatty acid formed when acetate is fed to the developing castor bean and is itself a precursor of ricinoleic acid. 

An initial or lag phase. This is when there is no fatty acid synthesis. The length of this phase varies from species to species (and even in the same species under varying environmental conditions [168]). In castor bean (Table 3.2) it lasts 20-25 days after pollination during which time the embryo and seed coat develop [38, 201], in rape seed for the first 4 weeks of development [136], and for the first 10-15 days in safflower [113, 169]. The delay before the initiation of fatty acid synthesis is due to the absence from the developing tissue of... 

Some of these unusual fatty acids, such as those of seed oils of castor bean, rape seed, coconut and palm kernel or tung nut have been exploited as raw materials for the chemical industry for some considerable time. They represent a stable and variable, albeit relatively minor fraction, of the world vegetable oil market. The quest for new oil seed crops which possess unusual fatty acids and are able to yield sufficient quantities of them on an economic scale have been prompted by diversification of industrial applications, changes in agricultural practices and production and, more recently, unreliable supplies of mineral oils which serve as the raw materials of the petrochemical industry. 

The seed lipases from five plant species were selected because of their differences In the fatty acid composition of the storage trlacylglycerols. Castor bean contains about 80% rlclnolelc acid maize seed possesses about... 

The above results imply that acetyl-CoA carboxylase may be the rate-limiting enzyme for de novo fatty acid synthesis. Indeed, in seeds the level of acetyl-CoA carboxylase activity correlate with the accumulation of lipid in developing castor bean and rape seeds. However, unlike the mammalian enzyme, plant acetyl-CoA carboxylase does not seem to be consistently stimulated by tricarboxylic acids c.f. . ... 

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