The modification of mammalian membrane polyunsaturated fatty acid composition in relation to membrane fluidity and function

Stubbs, Christopher D.; Smith, Anthony D.

doi:10.1016/0304-4157(84)90005-4

Cited by 1,521 publications

(672 citation statements)

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“…with age, whereas synthesis-secretion rates (product of conversion coefficient and unesterified plasma Introduction Docosahexaenoic acid (22:6n-3, DHA), a long-chain n-3 polyunsaturated fatty acid (PUFA), is enriched in brain and retina phospholipids, where it modulates membrane fluidity, regulates functions of membraneassociated proteins (Stubbs and Smith 1984;Salem et al 2001;Kim 2007), and participates in calciumindependent phospholipase A 2 mediated neurotransmission (Strokin et al 2003). DHA may be obtained directly from dietary sources, such as fish or fish products, or it can be synthesized from its nutritionally essential plant-derived precursor, α-linolenic acid (18:3n-3, α-LNA), through a series of elongation and desaturation steps (Sprecher 2000).…”

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confidence: 99%

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Gao

Taha

et al. 2012

AGE

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Docosahexaenoic acid (DHA,, an n-3 polyunsaturated fatty acid (PUFA) found at high concentrations in brain and retina and critical to their function, can be obtained from fish products or be synthesized from circulating α-linolenic acid (α-LNA, 18:3n-3) mainly in the liver. With aging, liver synthetic enzymes are reported reduced or unchanged in the rat. To test whether liver synthesis-secretion of DHA from α-LNA changes with age, we measured whole-body DHA conversion coefficients and rates in unanesthetized adult male Fischer-344 rats aged 10, 20, or 30 months, fed an eicosapentaenoic acid (EPA, 20:5n-3)-and DHAcontaining diet. Unesterified [U-13 C]α-LNA bound to albumin was infused intravenously for 2 h, while [ 13 C]-esterified n-3 PUFAs were measured in arterial plasma, as were unlabeled unesterified and esterified PUFA concentrations. Plasma unesterified n-3 PUFA concentrations declined with age, but esterified n-3 PUFA concentrations did not change significantly. Calculated conversion coefficients were not changed significantly with age, whereas synthesis-secretion rates (product of conversion coefficient and unesterified plasma α-LNA concentration) of esterified DHA and n-3 DPA were reduced. Turnovers of esterified n-3 PUFAs in plasma decreased with age, whereas half-lives increased. The results suggest that hepatic capacity to synthesize DHA and other n-3 PUFAs from circulating α-LNA is maintained with age in the rat, but that reduced plasma α-LNA availability reduces net synthesis-secretion. As unesterified plasma DHA is the form that is incorporated preferentially into brain phospholipid, its reduced synthesis may be deleterious to brain function in aged rats.

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confidence: 99%

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Gao

Taha

et al. 2012

AGE

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“…From these results, we can conclude that in our in vitro culture conditions, developed embryos accumulate intracellular lipid droplets. A similar situation has been described in tissue culture cells which tend to form lipid inclusion bodies, containing triacylglycerols, when they are growing in lipid rich culture media containing either flee fatty acid or plasma protein (35,34). Moreover, many types of cells modify the composition of their membrane phospholipid fatty acids during short-term culture if the type of lipid in the culture medium is restricted or enriched with a particular fatty acid (3,33).…”

Section: Discussionmentioning

confidence: 54%

Delipidating in vitro-produced bovine zygotes: Effect on further development and consequences for freezability

Díez

Heyman

Bourhis³

et al. 2001

Theriogenology

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To study the effect of partial removal of intracytoplasmatic lipids from bovine zygotes on their in vitro and in vivo survival, presumptive zygotes were delipidated by micromanipulation and cocultured with Veto cells in B2+10% FCS. Blastocyst rates of delipidated (n=960), sham (centrifuged but not delipidated, n=830) and control embryos (n=950) were 42.1, 42.3 and 39.9% respectively (P > 0.05). Day 7 blastocysts derived from delipidated zygotes had a mean of 123.9 + 45.6 nuclei compared to 137.5 + 32.9 for control blastocysts (P > 0.05). The full-term development of delipidated blastocysts after single transfer to recipients was similar to that of control IVF blastocysts (41.2% vs 45.4% respectively). To assess the effect of delipidation on the embryo tolerance to freczing/thawing, delipidated (n=73), control (n=67) and shmn (n=50) Day 7 blastocysts were frozen in 1.36 M glycerol + 0.25 M sucrose in PBS. After thawing, embryos were cocultured for 72 h with Vero cells in B2+10% FCS. Survival rates at 24 h were not significantly different between groups. However, in the delipidated group, the survival rate after 48 h in culture was significantly higher than in the control group (56.2 vs 39.8, P < 0.02), resulting in a higher hatching rate after 3 days in culture (45.2 vs 22.4, P < 0.02). Pregnancy rates for delipidated and control frozen/thawed embryos were respectively 10.5 and 22.2% (P > 0.05). Electron microscopic observations showed much fewer lipid droplets (and smaller) in delipated blastocysts than in controls. Taken together, our data show that delipidation of one cell stage bovine embryos is compatible with their normal development to term and has a beneficial effect on their tolerance to freezing and thawing at the blastocyst stage. This procedure, however, alters the developmental potential of such blastocysts, suggesting that maternally inherited lipid stores interfere with metabolic recovery after thawing.

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“…Introduction of subsequent unsaturated bonds has a progressively smaller effect than the introduction of the first one (Stubbs and Smith, 1984). The presence of saturated molecular species at high levels in biological membranes seems to be lethal irrespective of growth temperature in Synechocystis (Tasaka et al, 1996).…”

Section: Biological Importance Of Different Ways Of Temperaturedependmentioning

confidence: 96%

Differences in the control of the temperature‐dependent expression of four genes for desaturases in Synechocystis sp. PCC 6803

Los

Ray

Murata

1997

Molecular Microbiology

150

120

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SummaryCyanobacteria are capable of desaturating the fatty acids in their membrane lipids in response to decreases in temperature. The cyanobacterium, Synechocystis sp. PCC 6803, contains four desaturases, which specifically catalyse desaturation at the ⌬6, ⌬9, ⌬12 and 3 positions of fatty acids. The levels of the mRNAs transcribed from the genes that encode the ⌬6, ⌬12 and 3 desaturases increased about 10-fold, but at different rates, upon a decrease in temperature from 34ЊC to 22ЊC, whereas the level of the mRNA for the ⌬9 desaturase remained constant. The increases in the levels of mRNAs were caused both by the enhanced transcription and by the increased stability of the mRNAs at the low temperature. Western blotting analysis demonstrated that levels of the ⌬6, ⌬12 and 3 desaturases increased at different rates at the low temperature, while that of the ⌬9 desaturase remained constant. These observations indicate that the expression of the genes for the four desaturases is regulated by temperature in different ways.

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The modification of mammalian membrane polyunsaturated fatty acid composition in relation to membrane fluidity and function

Cited by 1,521 publications

References 455 publications

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

Delipidating in vitro-produced bovine zygotes: Effect on further development and consequences for freezability

Differences in the control of the temperature‐dependent expression of four genes for desaturases in Synechocystis sp. PCC 6803

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