Trienoic fatty acids

With the above procedure, dienoic fatty acid peroxidation products yield a conjugated triene chromophore with second-derivative absorption minima iocated at 258, 269.5 and 281 nm, whilst trienoic fatty-acid peroxidation products give rise to a conjugated tetraene chromophore with minima at 278, 289, 303 and 318 nm. The arrows in (c) denote second-derivative absorption minima corresponding to the conjugated triene adduct arising from linoleate-derived peroxidation products (conjugated hydroperoxydienes, hydroxydienes and oxodienes). 

Research concerning the structure, composition, and usefulness of cucurbit seeds (gourds, melons, squash, etc.) is reviewed. Cytological features are typical of those for oilseeds. Composition-ally, decorticated seeds contain by weight 50% oil and 35% protein. The oil is unsaturated and edible however, certain species contain conju-ated trienoic fatty acids (drying oils). 

Although all-trans-octadecatrienoate tended to elute with the cis-dienes, this was not a problem in practice with samples of hydrogenated fats containing dienoic and trienoic fatty acids. A gradient elution scheme was adapted from the isocratic mobile phase used for monoenes and polyenes for the separation of such mixtures. 

Suzuki, R., Noguchi, R., Ota, T., Abe, M., Miyashita, K., and Kawada,T. 2001. Cytotoxic effect of Conjugated trienoic fatty acids on mouse tumor and human monocytic leukemia cells. Lipids, 36,477-482. 

JAs are derived from linolenic acid via an octadecanoid pathway consisting of several enzymatic steps (Figure 36). Multiple compartments in plant cells participate in JA synthesis. The early steps of this pathway occur in chloroplasts, where linolenic acid is converted to OPDA by means of the three enzymes lipoxygenase (LOX), allene oxide synthase (AOS), and allene oxide cyclase (AOC).867-869 Linolenic acid is oxygenated by 13-LOX producing a peroxidized fatty acid 13-hydroperoxylinolenic acid. The product is subsequently metabolized by AOS to an unstable compound allene oxide. Allene oxide is sequentially converted by AOC to produce OPDA. An alternative pathway from another trienoic fatty acid, hexadecatrienoic acid (16 3), is present in chloroplasts.870 In this pathway, dinor OPDA is produced instead of OPDA. OPDA and dinor OPDA are transported into the peroxisome. An ABC transporter involved in this transport was identified in... 

Igarashi, M., and Miyazawa, T. (2000) Newly Recognized Cytotoxic Effect of Conjugated Trienoic Fatty Acids on Cultured Human Tumor Cells, Cancer Lett. 148,173-179. 

Fig. 17. Ultraviolet spectra of the trienoic fatty acids after alkali isomerization.

The common trienoic fatty acids are cis,cis,cis-9,12,15-octadecatrienoic acid (a-linolenic acid), cis,-c/s,cis-6,9,12-octadecatrienoic acid (y-linolenic acid), c/s,c/s,c/s-8,ll,14-icosatrienoic acid (dihomo-y-lino-lenic acid), 5,9,13-eicosatrienoic acid, and 5,9,13-docosatrienoic acid. An example of a tetraenoic fatty acid is ds,ds,ds,ds-5,8,ll,14-icosatetraenoic acid (arachidonic acid). The discovery of new polyunsaturated acids is an ongoing process, with the recent discovery of 5,9-heneicosadienoic acid, 5,9-do-cosadienoic acid, 5,9-tricosadienoic acid, trienoic 5,9,13-eicosatrienoic acid, and 5,9,13-docosatrienoic acid from Stoichactis helianthus. Geranoic acid (systematic name is 3,7,1 l,15-tetramethyl-2,6,10,14-hexadecatetraenoic acid) (Figure 9), nerolic and far-nesoic acids are polyunsaturated fatty acids with branches in their structures. 

We have achieved good separation of polyunsaturated fatty acid esters from saturated, monosaturated and disaturated fatty acid esters and this has been used as a means of identifying the presence of polyunsaturates, especially fish oil, in samples (Fig. 1.2). However, if there is a considerable amount of trienoic fatty acids in the mixture, as in egg lipids, the separation is not very pronounced (Shantha and Ackman, 1991a). Nakamura, Fukuda and Tanaka (1996) have used similar TLC separation of marine lipids and were able to quantitate the amount of pol)amsaturated fatty acids by using scanning densitometry followed by Coomassie blue staining. 

Suzuki, R., R. Noguchi, T. Ota, M. Abe, K. Miyashita, T. Kawada. Cytotoxic Effect of Conjugated Trienoic Fatty Acids on Mouse Tumor and Human Monocytic Leukemia Cells. Lipids, 36 477-482 (2001). 

LACK OF TRIENOIC FATTY ACIDS IN AN ARABIDOPSIS MUTANT INCREASES TOLERANCE OF PHOTOSYNHESIS TO HIGH TEMPERATURE... 

Oxygenic photosynthesis occurs in a uniquely constructed bilayer membrane known as thylakoid. The glycerolipid molecules that form the thylakoid membranes are characterized by their sugar head groups and a very high level of unsaturation in the fatty acid chains. In Arabidopsis, trienoic fatty acids - a-linolenic (18 3) and hexadecatrienoic acids (16 3) - account for more than 70% of the total fatty acids in thylakoid lipids. Therefore, this fatty acids might have some crucial role in maintaining photosynthetic functions. 

A TRIENOIC FATTY ACID DEFICIENT MUTANT OF ARABIDOPSIS IS DEFECTIVE IN RECOVERY FROM PHOTOINHIBITION AT LOW TEMPERATURES... 

Light dependent recovery from photoinhibition involves proteolytic degradation of the reaction center protein D1 in photoinactivated PS II centers, and its replacement with newly synthesized D1 polypeptide (3). The absence of trienoic fatty acids in the thylakoid lipids of the mutant/a -2fad8 probably inhibits one or more of the steps involved... 

Lack of Trienoic Fatty Acids in an Arabidopsis Mutant Increases Tolerance of Photosynthesis to High Temperature. 

A Trienoic Fatty Acid Deficient Mutant of Arabidopsis is Defective in Recovery from Photoinhibition at Low Temperatures. 

C.,g and C20 fatty acids of the (n-9), (n-6) and (n-3) families are the most abundant trienoic fatty acids in animal tissues they elute in this order on polar stationary phases and some ECL data are contained in Table 5.3. All of the eight possible geometrical isomers of 9,12,15-octadecatrienoic acid (a-linolenic acid) have been prepared by nitrous oxide-catalysed elaidinisation [21-23,815] and by total synthesis [747]. Ackman and Hooper [21-23] were able to predict their ECL values, from data for the appropriate monoenes obtained on a WCOT column coated with Silar 5CP , by applying diethylenic... 

Figure 3.20 Formation of oligomers from trienoic fatty acids.

An important factor is the presence of reactive double bonds. Saturated fatty acids are practically stable during fat storage at normal temperatures. At temperatures around 20 °C, monoenoic fatty acids (such as oleic acid) are only oxidised very slowly, dienoic fatty acids (such as hnoleic acid) are oxidised about ten times faster and trienoic fatty acids (such as Hnolenic acid) approximately 20 times faster. Arachidonic acid, as an example of tetraenoic fatty acids, is oxidised about 30-40 times faster. At temperatures above... 

The fadD mutant of Arabidopsis thalLana L. which has a reduced amount of trienoic fatty acids provides a useful tool for the study of linolenic acid biosynthesis. The maximum reduction of trienoic fatty acids in the fadD mutant is obtained at a growth temperature of 28°C. As the growth temperature decreases the effect of the mutation decreases to the point where the amount of trienoic fatty acid content of the fadD mutant resembles that of the wildtype. In this study the differential temperature and light effects between the two genotypes are reported. 

Igarashi, M and Miyazawa, T (2000) Newly recognized cytotoxic effect of conjugated trienoic fatty acids on cultured human tumor cells. Cancer Lett., 148, 173—179. 

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