Biosynthesis of 1,2‐dieicosapentaenoyl‐<i>sn‐</i>glycero‐3‐phosphocholine in <i>Caenorhabditis elegans</i>

Tanaka, Tamotsu; Izuwa, Shinya; Tanaka, Katsuhisa; Yamamoto, Daisuke; Takimoto, Tatsunori; Matsuura, Fumito; Satouchi, Kiyoshi

doi:10.1046/j.1432-1327.1999.00480.x

Cited by 17 publications

(12 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The source of vaccenic acid, dietary or de novo synthesis, that becomes incorporated in the longer second phase is not known, but its significance might be in substituting for 20:5(n-3) in the sn-1 position of di-20:5(n-3) PC. This is an unusual complex lipid that has been found in C. elegans and whose level is enhanced in long-term 15°C-reared worms compared with 25°C-reared worms (35). We found that 3 ablation by RNAi elicited no change in the cold tolerance phenotype (data not shown), suggesting that the proportion of 20:5(n-3) was not critical to cold tolerance and that other less unsaturated PUFAs can substitute.…”

Section: Discussionmentioning

confidence: 72%

An explicit test of the phospholipid saturation hypothesis of acquired cold tolerance in Caenorhabditis elegans

Murray

Hayward

Govan

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

134

105

View full text Add to dashboard Cite

Protection of poikilothermic animals from seasonal cold is widely regarded as being causally linked to changes in the unsaturation of membrane phospholipids, yet in animals this proposition remains formally untested. We have now achieved this by the genetic manipulation of lipid biosynthesis of Caenorhabditis elegans independent of temperature. Worms transferred from 25°C to 10°C develop over several days a much-increased tolerance of lethal cold (0°C) and also an increased phospholipid unsaturation, as in higher animal models. Of the three C. elegans ⌬9-desaturases, transcript levels of fat-7 only were up-regulated by cold transfer. RNAi suppression of fat-7 caused the induction of fat-5 desaturase, so to control desaturase expression we combined RNAi of fat-7 with a fat-5 knockout. These fat-5/fat-7 manipulated worms displayed the expected negative linear relationship between lipid saturation and cold tolerance at 0°C, an outcome confirmed by dietary rescue. However, this change in lipid saturation explains just 16% of the observed difference between cold tolerance of animals held at 25°C and 10°C. Thus, although the manipulated lipid saturation affects the tolerable thermal window, and altered ⌬9-desaturase expression accounts for cold-induced lipid adjustments, the effect is relatively small and none of the lipid manipulations were sufficient to convert worms between fully cold-sensitive and fully cold-tolerant states. Critically, transfer of 10°C-acclimated worms back to 25°C led to them restoring the usual cold-sensitive phenotype within 24 h despite retaining a lipid profile characteristic of 10°C worms. Other nonlipid mechanisms of acquired cold protection clearly dominate inducible cold tolerance.⌬9-acyl desaturase ͉ lipid composition ͉ RNAi

show abstract

Section: Discussionmentioning

confidence: 72%

An explicit test of the phospholipid saturation hypothesis of acquired cold tolerance in Caenorhabditis elegans

Murray

Hayward

Govan

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

134

105

View full text Add to dashboard Cite

show abstract

“…Ptdcholine concentration was found to be correlated with increased FT among 13 hardened wheat cultivars (Horváth et al, 1980). It is interesting to note that in C. elegans, where homologs of the wheat WPEAMT have been identified, LT treatment increases the level of several types of phosphatidylcholines (Tanaka et al, 1999). This finding suggests that nematodes and plants may share a common pathway for Ptd-choline biosynthesis.…”

Section: Table I In Vitro Phospho-base N-methyltransferase Activitiesmentioning

confidence: 93%

Molecular and Biochemical Characterization of a Cold-Regulated PhosphoethanolamineN-Methyltransferase from Wheat

et al. 2002

View full text Add to dashboard Cite

A cDNA that encodes a methyltransferase (MT) was cloned from a cold-acclimated wheat (Triticum aestivum) cDNA library. Molecular analysis indicated that the enzyme WPEAMT (wheat phosphoethanolamine [P-EA] MT) is a bipartite protein with two separate sets of S-adenosyl-l-Met-binding domains, one close to the N-terminal end and the second close to the C-terminal end. The recombinant protein was found to catalyze the three sequential methylations of P-EA to form phosphocholine, a key precursor for the synthesis of phosphatidylcholine and glycine betaine in plants. Deletion and mutation analyses of the two S-adenosyl-l-Met-binding domains indicated that the N-terminal domain could perform the three N-methylation steps transforming P-EA to phosphocholine. This is in contrast to the MT from spinach (Spinacia oleracea), suggesting a different functional evolution for the monocot enzyme. The truncated C-terminal and the N-terminal mutated enzyme were only able to methylate phosphomonomethylethanolamine and phosphodimethylethanolamine, but not P-EA. This may suggest that the C-terminal part is involved in regulating the rate and the equilibrium of the three methylation steps. Northern and western analyses demonstrated that both Wpeamt transcript and the corresponding protein are up-regulated during cold acclimation. This accumulation was associated with an increase in enzyme activity, suggesting that the higher activity is due to de novo protein synthesis. The role of this enzyme during cold acclimation and the development of freezing tolerance are discussed.Winter survival and crop productivity are influenced by many different winter stresses, such as freezing temperature, length of freezing period, ice encasement, flooding, and oxidative stress caused by low temperature (LT)-induced photoinhibition (Fowler et al., 1999). Exposure of plants to LT produces morphological, physiological, and biochemical changes that are often highly correlated with plant freezing tolerance (FT) and winter survival. These changes are regulated by LT at the gene expression level. Cold-regulated genes and their products have been identified and characterized in many species (Thomashow, 1999). The complexity of the LT response has made it difficult to separate genes responsible for LT acclimation and cold hardiness from those associated with metabolic adjustments to LT. To characterize the genetic components associated with LT response, a better understanding of the LTresponsive genes responsible for adaptation to winter stresses and their interaction with the environment is needed (Fowler et al., 1999).

show abstract

“…The assay was conducted as described previously [29]. Each incubation contained 32 nmol of 1‐acyl‐2‐lyso‐PtdCho or 1‐acyl‐2‐lyso‐PtdIns, 0.5 m m nicotinamide, 1.5 m m glutathione, 0.15 m KCl, 5 m m MgCl 2 , 0.25 m sucrose, 3.0 m m ATP, 0.1 m m CoA, 50 m m potassium phosphate buffer (pH 7.4), 0.2 mg protein of the microsomal fraction of HepG2 cells, and 50 nmol of fatty acid in a total volume of 1.0 mL.…”

Section: Methodsmentioning

confidence: 99%

Metabolic characterization of sciadonic acid (5c,11c,14c‐eicosatrienoic acid) as an effective substitute for arachidonate of phosphatidylinositol

Tanaka

Morishige

Takimoto

et al. 2001

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

Sciadonic acid (20:3 Δ‐5,11,14) is an n‐6 series trienoic acid that lacks the Δ8 double bond of arachidonic acid. This fatty acid is not converted to arachidonic acid in higher animals. In this study, we characterized the metabolic behavior of sciadonic acid in the process of acylation to phospholipid of HepG2 cells. One of the characteristics of fatty acid compositions of phospholipids in sciadonic acid‐supplemented cells is a higher proportion of sciadonic acid in phosphatidylinositol (PtdIns) (27.4%) than in phosphatidylethanolamine (PtdEtn) (23.2%), phosphatidylcholine (PtdCho) (17.3%) and phosphatidylserine (PtdSer) (20.1%). Similarly, the proportion of arachidonic acid was higher in PtdIns (35.8%) than in PtdEtn (29.1%), PtdSer (18.2%) and PtdCho (20.2%) in arachidonic‐acid‐supplemented cells. The extensive accumulation of sciadonic acid in PtdIns resulted in the enrichment of newly formed 1‐stearoyl‐2‐sciadonoyl molecular species (38%) in PtdIns and caused the reduction in the level of pre‐existing arachidonic‐acid‐containing molecular species. The kinetics of incorporation of sciadonic acid to PtdEtn, PtdSer and PtdIns of cells were similar to those of arachidonic acid. In contrast to sciadonic acid, neither eicosapentaenoic acid (20:5 Δ‐5,8,11,14,17) nor juniperonic acid (20:4 Δ‐5,11,14,17) accumulated in the PtdIns fraction. Rather, these n‐3 series polyunsaturated fatty acids, once incorporated into PtdIns, tended to be excluded from PtdIns. In addition, the level of arachidonic‐acid‐containing PtdIns molecular species remained unchanged by eicosapentaenoic‐acid‐supplementation. These results suggest that sciadonic acid or sciadonic‐acid‐containing glycerides are metabolized in a similar manner to arachidonic acid or arachidonic‐acid‐containing glyceride in the biosynthesis of PtdIns and that sciadonic acid can effectively modify the molecular species composition of PtdIns in HepG2 cells. In this regard, sciadonic acid will be an interesting experimental tool to clarify the significance of arachidonic acid‐residue of PtdIns‐origin bioactive lipids.

show abstract

Biosynthesis of 1,2‐dieicosapentaenoyl‐sn‐glycero‐3‐phosphocholine in Caenorhabditis elegans

Cited by 17 publications

References 34 publications

An explicit test of the phospholipid saturation hypothesis of acquired cold tolerance in Caenorhabditis elegans

An explicit test of the phospholipid saturation hypothesis of acquired cold tolerance in Caenorhabditis elegans

Molecular and Biochemical Characterization of a Cold-Regulated PhosphoethanolamineN-Methyltransferase from Wheat

Metabolic characterization of sciadonic acid (5c,11c,14c‐eicosatrienoic acid) as an effective substitute for arachidonate of phosphatidylinositol

Contact Info

Product

Resources

About