Synthesis of phosphatidylcholine through phosphatidylethanolamine N-methylation in tissues of the mussel Mytilus galloprovincialis.

We previously demonstrated the importance of upregulation of phosphatidylethanolamine N-methylation pathway in euryhaline fish and crustaceans facing hyperosmotic conditions. In marine molluscs phosphatidylcholine synthesis through N-methylation of phosphatidylethanolamine has not been described until now. In vivo labeling of the mussel Mytilus galloprovincialis with [1-(3)H]-ethanolamine showed that the digestive gland is the tissue expressing the highest incorporation into lipids.

Salinity regulates N-methylation of phosphatidylethanolamine in euryhaline crustaceans hepatopancreas and exchange of newly-formed phosphatidylcholine with hemolymph.

Phosphatidylcholine (PC), the main phospholipid in eukaryotes, is synthesized via two different routes, the phosphatidylethanolamine N-methyl transferase (PEMT) and the CDP-choline pathways. We previously showed in euryhaline fish that salinity impacts the relative contribution of the two pathways for PC biosynthesis, with PEMT pathway being activated in the liver of sea water (SW)-adapted animals. To address the occurrence of such phenomenon in other animals we performed in vivo metabolic studies in two crustacean species: the Chinese crab (Eriocheir sinensis) and the green crab (Carcinus maenas).

Interactions of free copper (II) ions alone or in complex with iron (III) ions with erythrocytes of marine fish Dicentrarchus labrax.

As a consequence of human activity, various toxicants - especially metal ions - enter aquatic ecosystems and many fish are exposed to considerable levels. As the free ion and in some complexes, there is no doubt that copper promotes damage to cellular molecules and structures through radical formation. Therefore, we have investigated the influence of copper uptake by the red blood of the sea bass (Dicentrarchus labrax), and its oxidative action and effects on cells in the presence of complexed and uncomplexed Fe3+ ions.

Correlation between changes in blood fatty acid composition and visual sustained attention performance in children with inattention: effect of dietary n-3 fatty acids containing phospholipids.

Background: Increasing evidence supports n-3 fatty acid (FA) supplementation for patients with psychiatric disorders, such as attention deficit hyperactivity disorder. However, the exact metabolic fate of dietary eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on different glyceride carriers remains unclear.

Objective: We investigated whether conjugation of EPA and DHA to phospholipid (PL-n-3) or to triacylglycerol (fish oil; FO) affects their incorporation in blood compartments and influences executive functioning.

Changes in the fatty acid composition of phospholipids in tissues of farmed sea bass (Dicentrarchus labrax) during an annual cycle. Roles of environmental temperature and salinity.

We quantified seasonal effects on fatty acid composition of tissue phospholipids in farmed sea bass. Major changes in percent phosphatidylethanolamine and phosphatidylcholine were observed in all tissues between February and March, and the phosphatidylcholine/phosphatidylethanolamine ratio was drastically reduced at this time. Different changes in the fatty acid composition of total phospholipids were observed in all tissues examined.

Plasma and muscle phospholipids are involved in the metabolic response to long-distance migration in a shorebird.

We studied: (1) concentrations and fatty acid compositions of plasma non-esterified fatty acids, neutral lipids, and phospholipids, and (2) fatty acid composition of flight muscle phospholipids in wintering, premigratory, and spring and fall migrating western sandpipers ( Calidris mauri). Plasma neutral lipid and phospholipid levels were elevated in migrants, reflecting high rates of fat deposition. An important role of phospholipids in fattening is suggested by the fact that the amount of fatty acids in plasma phospholipids was similar to, or in spring as much as twice, that of neutral lipids.

Palmitate and oleate metabolism of rainbow trout in vivo.

The turnover rates of palmitate and oleate were measured in vivo by continuous infusion of 1-[14C]palmitate and 9,10-[3H]oleate in rainbow trout. Our goals were: (1) to quantify the incorporation of a saturated and of a monounsaturated fatty acid into other classes of plasma lipids (neutral lipids, NL, and phospholipids, PL); and (2) to determine whether they could both be used as tracers to quantify fluxes of total non-esterified fatty acids (NEFA). We found that both acids play very different physiological roles because palmitate is preferentially channeled towards plasma PL, whereas oleate is mainly incorporated in circulating NL.

Effects of L-thyroxine on incorporation of (32)P into phospholipids of freshwater eels.

The effects of L-thyroxine on phospholipid biosynthesis, via (32)P incorporation, were studied in gill, kidney, liver and muscle tissue of eels acclimatized at 11 degrees C. L-thyroxine treatment had no effect on tissue content of lipid, inorganic and organic acid-soluble phosphorus. Only an increase of the specific radioactivities of lipid, inorganic and organic acid-soluble phosphorus was observed in the muscle.

Effects of zinc on lipids of erythrocytes from carp (Cyprinus carpio L.) acclimated to different temperatures.

We compared the effect of zinc (0.01, 0.1, 0.

A procedure for fractionation of sphingolipid classes by solid-phase extraction on aminopropyl cartridges.

Solid-phase extraction (SPE) methods are easy, rapid, and reliable. Their growing popularity is in part due to their operational simplicity and cost reduction in solvents, and partly because they are easier to automate. Sphingolipids are implicated in various cellular events such as growth, differentiation, and apoptosis.

Differential labelling of sphingolipids by [3H]serine and ([3H]methyl)-methionine in fish leukocytes.

Long chain bases are constituents of all sphingolipids and their biosynthesis is presumed to occur via the initial condensation of serine with palmitoyl-CoA. The biosynthesis of phytosphingosine, a long chain base containing three hydroxyl groups, has been less studied than sphingosine but is assumed to occur by hydroxylation of sphinganine. We report in this paper that the label from ([3H]methyl)-methionine is preferentially incorporated into phytosphingosine bases of neutral glycosphingolipids, whereas the label from [3H]serine is mainly incorporated into the sphingoid base of sphingomyelin.

Phytosphingosine biosynthesis differs from sphingosine in fish leukocytes and involves a transfer of methyl groups from [3H-methyl]methionine precursor.

We have studied the incorporation of radioactivity from either [3-3H]serine as the direct or [3H-methyl]methionine as the indirect precursor into sphingoid bases of free ceramides in lymphocytes from fish. Radioactivity from serine was incorporated mostly in the sphingosine moiety of ceramides. In contrast, the radioactivity from methionine was exclusively incorporated into phytosphingosine base (i.

A two-dimensional thin-layer chromatography procedure for simultaneous separation of ceramide and diacylglycerol species.

We have developed a novel, simple, and rapid, two-dimensional thin-layer chromatography method to separate 1,2-, 1,3-diacylglycerols and ceramides containing alpha-hydroxy and normal fatty acids from other neutral lipids on one 10 x 10 cm precoated silica gel plate. The three solvent systems used in succession leave the phospholipids at the origin and separate neutral lipids of interest into component species. We have applied this method to incorporation of 9,10-[3H]myristic acid into lipids of gills from sea bass and obtained results that are similar and comparable to those obtained by described methods.

Design of the oxygen and substrate pathways. IV. Partitioning energy provision from fatty acids.

This paper quantifies the fluxes of fatty acids through the pathways supplying muscle mitochondria with oxidative fuel in exercising dogs and goats. We used continuous infusions of 1-[14C]palmitate and indirect calorimetry to measure fatty acid supply from two sources: the circulation and the triglyceride stores within the muscle cells. Our goal was to determine maximal flux through these two branches of the lipid pathway as key functional parameters for testing the principle of symmorphosis, i.

Design of the oxygen and substrate pathways. I. Model and strategy to test symmorphosis in a network structure.

This first paper in a series develops a model of structure-function relationships for the oxygen and substrate pathways of oxidative metabolism in working muscle. This will be used in the subsequent experimental papers in asking how biological structures are designed if they serve more than one function and whether one function can be served by more than one structural pathway. We have used the concept of symmorphosis to address this question; in its original form, it postulates that no more structure is built and maintained at each step in a pathway than is required to meet functional demands.

Sphingomyelin metabolism is linked to salt transport in the gills of euryhaline fish.

By in vivo and in vitro studies of L-(3-3H)serine and [9,10(n)-3H]palmitic acid incorporation into phospholipids, we show a change in the renewal of the ceramide moiety of sphingomyelin in the gills of euryhaline fish (sea bass and eels) when the animals were subjected to abrupt alterations in environmental salinity. In vivo, decrease of the salinity from sea water (salinity 3.7%) to diluted sea water (salinity 1%) induced an increase of label incorporation into gill sphingomyelin.

Interferon alpha/beta induces changes in the metabolism of polyenoic phospholipids and diacylglycerols in the livers of suckling mice.

Suckling mice were injected daily from birth for 10 days with potent preparations of mouse interferon alpha/beta. Interferon treatment resulted in a markedly lower concentration of polyunsaturated fatty acids (20:4 omega 6 and 22:6 omega 3) in the two principal liver phospholipids, phosphatidylcholine and phosphatidylethanolamine, than in livers of control-treated mice. This effect appeared to correlate with a low level of synthesis of polyunsaturated phospholipids in the livers of interferon-treated mice.

Imprints of virus infection: can paramyxoviruses permanently modify triacylglycerol metabolism?

We have examined whether the passage of a paramyxovirus in a cell (BGM, African green monkey kidney) or animal (Swiss mouse) can permanently modify its metabolism. In an in vitro model in which cells had been cured of a measles virus persistent infection, the cells retained the modifications affecting lipid metabolism and composition induced during the infection. In a canine distemper virus mouse model, the same virus-induced modifications were observed in mice after the virus had been eliminated.

[Influence of the acclimation temperature on the phospholipid metabolism of the fresh water ell (Anguilla anguilla) (author's transl)].

Lowering of the acclimation temperature of the eel induced a reduction of 32P incorporation into the lipid phosphorus of various tissues. This effect was partly the result of a slight decrease of the inorganic phosphate exchange and metabolism of tissues. 2.

[Comparative metabolism of phospholipids of osmoregulation effector organs in European eel (Anguilla anguilla)].

The phospholipid composition from various organs of the fresh water eel, such as gill, kidney, gut, liver and muscle, were determined by thin-layer chromatography. The major phosphatides found in these tissues were PC, PE and SPH and minor constituents PS, PI, DPG, AP and also LPC in the gut. A greater percentage of PS and SPH occurs in the osmoregulatory effector organs such as gill, kidney, and gut.