Sub‐cellular localization of the oleyl‐CoA desaturase activity in pea leaves

Dubacq, Jean‐Paul; Mazliak, P.; Trémolières, A.

doi:10.1016/0014-5793(76)80499-1

Cited by 23 publications

(12 citation statements)

References 13 publications

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“…9), at least after 12 hr of greening, has also been observed in isolated plastids from Hordeum vulgare leaves, although the incorporation did eventually rise after 48+ hr of greening here (14). Acetate The actual subcellular location and mechanism of desaturation are a subject of some controversy at present (5,6,9,24,25). In the present studies it was noted that both [1- …”

Section: Resultssupporting

confidence: 55%

“…Isolated chloroplasts have been shown to be incapable of synthesizing significant amounts of polyunsaturated fatty acid to date (16); the principal product of in vitro incubations with fatty acid precursors is oleate, either in free or esterified form (6,18,27). It has been proposed that further desaturation of oleate occurs in an extrachloroplastic location, possibly in a microsomal fraction, where the acyl substrate is esterified to phosphatidyl choline (6,9,25).…”

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confidence: 99%

“…It has been proposed that further desaturation of oleate occurs in an extrachloroplastic location, possibly in a microsomal fraction, where the acyl substrate is esterified to phosphatidyl choline (6,9,25). In addition, hexadecatrienoic acid (16:3 [7,10,13]) has been ' Supported in part by National Institute of General Medical Sciences 2R01 GM19213-07.…”

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confidence: 99%

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Light-dependent Induction of Polyunsaturated Fatty Acid Biosynthesis in Greening Cucumber Cotyledons

Murphy¹,

Stumpf²

1979

Plant Physiol.

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Greening cucumber ( Cucumis sativus L.) cotyledons exhibited dramatic increases in the ability to desaturate exogenously added 11-t4CIoleic acid and II_14Cllinoleic acid within 2 to 3 hours of illumination. These increases were effectively inhibited by 10 micrograms per milliliter cycloheximide. Oleate desaturation remained at a high level in constant light for 5 to 6 days after induction and then declined by about 50%; when returned to the dark, the tissue showed a sharp decrease in conversion of 114CIoleate to 114Cllinoleate. Linoleate desaturation reached a maximum about 15 hours after induction and declined immediately thereafter while the tissue still was in the light; after induction had peaked return of the tissue to the dark showed a dramatic fall of linoleate desaturation. The changes in desaturation were correlated with the conversion of the principal fatty acid in the etiolated cotyledons, linoleate, to a-linolenate, and with the assembly of the chlorophyll-containing photosynthetic membranes. The incorporation of 11-4Clacetate into lipids showed no significant light stimulation. The role of light in the regulation of certain aspects of plant metabolism during development is discussed.

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Section: Resultssupporting

confidence: 55%

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confidence: 99%

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Light-dependent Induction of Polyunsaturated Fatty Acid Biosynthesis in Greening Cucumber Cotyledons

Murphy¹,

Stumpf²

1979

Plant Physiol.

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“…The 16:O and 18:l fatty acids are then utilized by two distinct pathways for the biosynthesis of membrane glycerolipids and the coordinate desaturation of the acyl chains to produce polyunsaturated fatty acids. The basis of the twopathway hypothesis (Roughan et al, 1980;Roughan and Slack, 1982) is that fatty acids synthesized de novo in the chloroplast (Ohlrogge et al, 1979) may be used either for the production of chloroplast lipids via the prokaryotic pathway (Roughan et al, 1980) or exported as COA esters (Block et al, 1983) to enter the eukaryotic pathway at extrachloroplast sites, particularly in the ER (Slack and Roughan, 1975;Dubacq et al, 1976;Slack et al, 1976;Simpson and Williams, 1979). The DAG moiety of PC synthesized by the eukaryotic pathway can be retumed to the chloroplast, where it contributes to the production of thylakoid lipids (Slack and Roughan, 1975;Williams et al, 1976;Slack et al, 1977).…”

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confidence: 99%

A Mutant of Arabidopsis with Increased Levels of Stearic Acid

1994

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A mutation at the fab2 locus of Arabidopsis caused increased levels of stearate in leaves. l h e increase in leaf stearate in fab2 varied developmentally, and the largest increase occurred in young leaves, where stearate accounted for almost 20% of total leaf fatty acids. The fatty acid composition of leaf lipids isolated from the fab2 mutant showed increased stearate in all the major glycero-lipids of both the chloroplast and extrachloroplast membranes. Although the stearate content was increased, the fab2 mutant still contained abundant amounts of 18:1, 182, and 1 8 3 fatty acids. lhese results are consistent with the expectations for a mutation partially affeding the action of the stromal stearoyl-acyl carrier protein desaturase. Positional analysis indicated that the extra 18:O is excluded with high specificity from the sn-2 position of both chloroplast and extrachloroplast glycerolipids. Although stearate content was increased in all the major leaf membrane lipids, the amount of increase varied considerably among the different lipids, from a high of 25% of fatty acids in phosphatidylcholine to a low of 2.9% of fatty acids in monogalactosyldiacylglycerol. The membrane lipid composition of plants differs from that of animals and fungi primarily in the composition of the chloroplast membranes and in a higher overall leve1 of un-saturation. The chloroplast membranes are composed almost entirely of the uncharged galactolipids MGD and DGD, which make up about 75% of the total chloroplast thylakoid lipid (Webb and Green, 1991). Depending upon the plant species, trienoic fatty acids (18:3 and 16:3) constitute up to 80% of the fatty acids in this organelle (Murphy, 1986). Although these features are common to a11 higher plants, it remains unclear how these characteristic lipid components are important to the physiology and cell biology of plants. In plants, de novo fatty acid synthesis occurs exclusively in the plastids (Ohlrogge and Kuo, 1985). The plant fatty acid synthase is composed of individual proteins (Shimakata and Stumpf, 1982), and the primary products of this type I1 synthase are 16:O-ACP and 18:O-ACP (Roughan et al., 1979). The 18:O-ACP is normally desaturated with high efficiency '

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“…Palmitic and oleic acids are synthesized in the plastids. It is assumed at present that further desaturation of this last fatty acid to linoleate takes place in the microsomal fraction (Dubacq et al 1976;Slack et al 1976), probably in the endoplasmic reticulum. The substrate is oleoylgly-cerophosphocholine (Slack et al 1976) via oleoyl-CoA (Trrmolirres et al 1980.…”

Section: Discussionmentioning

confidence: 99%

Correlation between the endogenous circadian rhythmicity in growth rate and fluctuations in oleic acid content in expanding stems of Chenopodium rubrum L.

Lecharny

Trémolières²,

Wagner

1990

Planta

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Chenopodium rubrum L. plants exhibit an endogenous circadian rhythm in their instantaneous stem extension rate in continuous light (A. Lecharny and E. Wagner, 1984, Physiol. Plant. 60, 447-453). Stem extension rate and fatty-acid composition of two stem parts were measured in plants kept in continuous light for 90 h following a 12-h dark period. Fluctuations in the relative size of the oleic acid pool were evidenced in the stem tissues. The peaks (minima and maxima) of the oleic acid content occurred at the same times after the end of the 12-h dark periods as the peaks of the stem extension rate. This rhythmic behaviour ceased when growth was completed. No significant rhythmic changes were observed in any other fatty acid pools. Lipids in which the oleate content is rhythmically modified were exclusively phosphatidylcholine and phospha-tidylethanolamine. Thus, there was a specific correlation between the relative amount of oleic acid in phosphatidylcholine and phosphatidylethanolamine and the rate of instantaneous growth in the same tissue. The rhythmic variations in the oleic acid may be linked to the endomembrane flow in relation to the rate of growth.

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Sub‐cellular localization of the oleyl‐CoA desaturase activity in pea leaves

Cited by 23 publications

References 13 publications

Light-dependent Induction of Polyunsaturated Fatty Acid Biosynthesis in Greening Cucumber Cotyledons

Light-dependent Induction of Polyunsaturated Fatty Acid Biosynthesis in Greening Cucumber Cotyledons

A Mutant of Arabidopsis with Increased Levels of Stearic Acid

Correlation between the endogenous circadian rhythmicity in growth rate and fluctuations in oleic acid content in expanding stems of Chenopodium rubrum L.

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