Lower Concentrations Of Phosphatidylcholine Research Articles

High lysophosphatidylcholine and low phosphatidylcholine concentrations in HDL phospholipids are associated with atherosclerosis in relation to decreased cholesterol efflux capacity

High lysophosphatidylcholine and low phosphatidylcholine concentrations in HDL phospholipids are associated with atherosclerosis in relation to decreased cholesterol efflux capacity

Biochemical phenotyping of multiple myeloma patients at diagnosis reveals a disorder of mitochondrial complexes I and II and a Hartnup-like disturbance as underlying conditions, also influencing different stages of the disease

The aim of this study was to identify novel plasma metabolic signatures with possible relevance during multiple myeloma (MM) development and progression. A biochemical quantitative phenotyping platform based on targeted electrospray ionization tandem mass spectrometry technology was used to aid in the identification of any eventual perturbed biochemical pathway in peripheral blood plasma from 36 MM patients and 73 healthy controls. Our results showed that MM cases present an increase in short and medium/long-chain species of acylcarnitines resembling Multiple AcylCoA Dehydrogenase Deficiency (MADD), particularly, associated with MM advanced International Staging System (ISS). Lipids profile showed lower concentrations of phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and sphingomyelins (SM) in the MM patients and its respective ISS groups. MM cases were accompanied by a drop in the concentration of essential amino acids, especially tryptophan, with a significant inverse correlation between the progressive drop in tryptophan with the elevation of β2-microglobulin, with the increase in systemic methylation levels (Symmetric Arginine Dimethylation, SDMA) and with the accumulation of esterified carnitines in relation to free carnitine (AcylC/C0). Serotonin was significantly elevated in cases of MM, without a clear association with ISS. Kynurenine/tryptophan ratio demonstrates that the activity of dioxigenases is even higher in the cases classified as ISS 3. In conclusion, our study showed that MM patients at diagnosis showed metabolic disorders resembling both mitochondrial complexes I and II and Hartnup-like disturbances as underlying conditions, also influencing different stages of the disease.

NMR study of lipid changes in organs of jirds infected with Echinococcus multilocularis

Proton NMR spectroscopy was used to investigate changes in composition of lipids in the liver, kidneys and adrenal glands of Meriones unguiculatus infected with Echinococcus multilocularis. It was found that all three organs of infected animals had less total glycerophospholipid and CH 2 in the fatty acid (FA) component CHCH(CH 2CHCH) n than the corresponding organs of uninfected animals. The concentrations of other lipids in these organs were variable in their response to infection. The livers of infected jirds had lower concentrations of phosphatidylcholine (PTC), phosphatidylinositol, cholesterol (CTL) and the FA component CH 2CH 2COO, but more phosphatidylethanolamine (PTE). Kidneys of infected animals had less PTC, PTE and arachidonic acid. The adrenal glands, which were most affected by E. multilocularis infection, had lower concentrations of PTE, CTL, total FA, triacylglycerol, linoleic acid, and the FA components CH 2CH 2COO, CH 2COO, CH 2 in (CH 2) n , CHCH and CH 2CHCH.

Calcium is not required for 5-lipoxygenase activity at high phosphatidyl choline vesicle concentrations.

5-Lipoxygenase (5-LO) catalyzes the formation of 5-hydroperoxy-eicosatetraenoic acid (5-HPETE) and leukotriene A4 (LTA4) from arachidonic acid. Following a rise in intracellular calcium, 5-LO translocates to a membrane where it reacts with arachidonic acid via an 18 kD protein (FLAP). In vitro studies using a vesicle system of phosphatidylcholine (PC) and purified 5-LO were conducted under varying concentrations of PC and calcium. At high PC concentrations, 5-LO partitioned onto the vesicle containing arachidonic acid, resulting in product formation in the absence of calcium. Addition of calcium increased the initial rate of the reaction with a small increase in product accumulation. Dilution experiments in the absence of calcium at high PC concentrations indicated that binding of 5-LO to the vesicles is rapidly reversible. In the presence of calcium, this binding is much more favorable than without calcium. Stimulation of 5-LO activity by dithiothreitol (DTT) was more pronounced at high PC concentrations than at low PC concentrations. The requirement for ATP for maximal activity was independent of vesicle concentration. Inhibitors that functioned in the conditions of low PC with calcium present also inhibited under high PC without calcium. In the presence of PC and calcium and without substrate, the enzyme was unstable and was rapidly and irreversibly inactivated. In high PC without calcium, the enzyme was much more stable but it was still subject to turnover-dependent inactivation. Fluorescence energy-transfer experiments confirmed the kinetic findings that 5-LO could bind to the vesicle in the absence of calcium. These results show that in the absence of calcium, 5-LO can reversibly bind to the vesicle containing arachidonic acid and produce the same amount of product by a similar mechanism as observed with low PC and calcium. Calcium likely causes a conformational change that increases the affinity of the enzyme for the vesicle, but it is not strictly required for enzymatic activity and has no effect on the function of the catalytic site.

Cobalt-Vitamin B-12 Deficiency Decreases Methionine Synthase Activity and Phospholipid Methylation in Sheep

Two groups of lambs were fed either a Co-deficient or a Co-sufficient whole barley-based diet for 28 wk to induce a severe Co-vitamin B-12 deficiency. Holo and apo methionine synthase activities were significantly lower in the liver, kidney and spinal cord of Co-deficient animals compared with controls. Neither form of this enzyme in the brain was affected by Co deficiency. The ratio of the tissue concentrations of S-adenosyl methionine to S-adenosyl homocysteine was significantly lower only in the liver of Co-deficient animals, suggesting that the activity of hepatic SAM-dependent methyltransferase enzymes would be impaired. Measurements of tissue concentrations of phosphatidyl choline and phosphatidyl ethanolamine revealed lower concentrations of phosphatidyl choline and a lower phosphatidyl choline:phosphatidyl ethanolamine ratio in both liver and brain of the Co-deficient animals. The latter finding occurred in the absence of changes in either methionine synthase activity or the methylation ratio and may result from impaired availability of hepatic phosphatidyl choline for transport into the brain.

Increasing productivity by removing choline in conversion of phosphatidylcholine to phosphatidylserine by phospholipase D

Abstract The conversion of phosphatidylcholine (PC) to phosphatidylserine (PS) was examined in the presence of l -serine (3.4 M, solubility of serine) using two phospholipase D (PLD) preparations of Streptomyces origin. A biphasic reaction was carried out at 30°C using an aqueous phase containing both PLD and serine and a solvent (ethyl acetate or diethyl ether) phase containing PC. With an increase in the PC concentration from 17.8 mM to 106.8 mM, the conversion decreased from 85% to 36% in 30 min. The effect of choline inhibition was investigated in two ways—by the addition of choline chloride at low PC concentrations and by removing choline enzymatically or physically during the progress of the reaction at high PC concentrations. The addition of various concentrations of choline chloride decreased the reaction rate, conversion and selectivity. The unreacted PC decreased from 36% to 17.6% and further to 1.6% by the addition of choline oxidase and a mixture of choline oxidase and catalase, respectively. There were no decreases in either the selectivity or the final PS content for the ten repeated batches examined when choline released was washed out from the PLD gels immobilized in Octyl-Sepharose CL-4B after each run.