Serine Phosphoglycerides Research Articles

The effects of phospholipase C ( Clostridium perfringens) on purified myelin

Fragments of purified myelin, treated with crude phospholipase C (EC 3.1.4.3) from Clostridium perfringens, lost an average of 64% of the lipid-P content, comprising 81% of the sphingomyelin, 92% of the choline phosphoglyceride, 71% of the ethanolamine phosphoglyceride and 14% of the serine phosphoglyceride. The enzyme was capable of penetrating the multi-layered membranes of the myelin fragments. Small quantities of the enzyme were detectable in the treated fragments. At 5°, substantial quantities of phospholipase C activity became bound to the myelin without showing any hydrolytic action. Most of this enzyme was released into solution on incubation at 38° for 1 h. The ultrastructural morphology of myelin changed little after phospholipase C treatment, except for the appearance of large globules embedded in the membranes. The serological activity of myelin was not appreciably affected by enzyme treatment.

THE INFLUENCE OF DIETARY FATS ON PLATELETS IN MAN

Abstract. Two groups, each of 10 subjects, have been given isocaloric diets for 21 days. The diets were identical with the exception of their fat content. One group was given 40% of the calories as soybean oil, and the other the same amount as MCT oil. Platelet and serum lipids and platelet function tests were evaluated before and after the dietary period. The platelet lipid analysis included estimation of total cholesterol and phospholipids, fractionation of phospholipids by thin layer chromatography and gas liquid chromatographic estimation of the fatty acid and aldehyde composition of the various phospholipids. Platelet function tests included platelet factor‐3 (PF‐3) activity and availability, platelet aggregation induced by collagen, ADP and thrombin and platelet electrophoresis. In subjects given a soybean oil diet a significant reduction in serum total cholesterol and phospholipids occurred. No changes were observed in the platelet cholesterol and phospholipid levels, whereas a significant increase of linoleic acid in choline, ethanolamine and serine phosphoglycerides took place. The relative increase of linoleic acid was most marked in the choline phosphoglycerides. A moderate decrease in palmitic and oleic acids was seen in most phospholipid fractions. PF‐3 activity in platelet‐rich plasma showed a consistent decrease in these subjects, whereas the other platelet function tests showed insignificant changes. In subjects given MCT oil diet no significant changes were observed in serum or platelet lipids, including the phospholipid fatty acids. Increased PF‐3 activity in platelet‐rich plasma exposed to ADP was the only functional disturbance observed in this group.

The acyl and alk-1-enyl groups of the major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions.

AbstractThe major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions were separated by preparative thin layer chromatography. Alk‐1‐enyl groups from the alk‐1‐enyl acyl glycerophosphorylethanolamines were reacted with 1,3‐propanediol to form the 1,3‐dioxolane derivatives. Acyl groups were converted to the methyl ester derivatives and the acyl groups from alk‐1‐enyl acyl glycerophosphorylethanolamines and diacyl glycerophosphorylethanolamines were also determined separately. The acyl and alk‐1‐enyl group compositions of the phosphoglycerides from microsomal and mitochondrial fractions were quite similar. The ethanolamine and serine phosphoglycerides contained large amounts of 18∶0, 18∶1, 20∶4 and 22∶6 acyl groups. The choline phosphoglycerides had small amounts of polyunsaturated acyl groups and large amounts of 16∶0, 18∶1 and 18∶0 acyl groups. The mitochondrial cardiolipins contained unusual amounts of several acyl groups including 18∶1, 52%; 18∶2, 6%; and 16.1, 4%. A large portion of the mouse brain 18∶2 is in that fraction. The myelin phosphoglycerides were deficient in saturated and 22∶6 groups and markedly enriched in 18∶1 and 20∶1 groups when compared with the corresponding microsomal or mitochondrial phosphoglycerides.

Platelet phospholipids and their function in patients with juvenile diabetes and maturity onset diabetes.

Platelet factor-3 activity and availability, platelet phospholipids and their fatty acid and aldehyde composition were examined in patients with juvenile diabetes of long duration and in patients with maturity onset diabetes. Increased coagulant activity was found in platelet rich and platelet poor plasma from patients with juvenile diabetes, whereas plasma from patients with maturity onset diabetes reacted as the control group. Platelet rich plasma exposed to ADP, kaolin or freezing and thawing three times reacted not significantly differently from the controls. Increased amount of lipid-P was present in platelets from both patient groups. In patients with juvenile diabetes the increase was mainly caused by an increase of serine phos-phoglycerides and in the other patient group all main phos-pholipid fractions were increased. The phospholipid/protein ratio of platelets was not significantly different in the three groups. Only moderate changes were observed in the fatty acid pattern of the various phospholipids.

BRAIN LIPID MODIFICATIONS INDUCED BY ESSENTIAL FATTY ACID DEFICIENCY IN GROWING MALE AND FEMALE RATS

Abstract—Essential fatty acid (EFA) deficiency initiated in rats prior to birth and continued for one year affects brain lipids to an extent which differs in the two sexes. It was found that:(1) Brain weight and lipid content were decreased in deficient conditions, especially in males.(2) Total phospholipids were present in lower concentrations, particularly in the deficient male brain, while the percentage of the major phospholipid classes‐ethanolamine phosphoglyceride (EPG), choline phosphoglyceride (CPG) and serine phosphoglyceride (SPG) did not change.(3) Brain EPG, CPG and SPG had distinctive fatty acid patterns differing greatly in polyunsaturation content. PE acids of control females had elevated monoenes and reduced saturates in comparison with control males. This sex difference was lost in the deficient animals.(4) Polyunsaturated fatty acids of EPG, CPG and SPG were markedly changed in animals lacking dietary linoleic acid. Trienoic (C20 and C22) and docosapentaenoic acids were greatly increased, whereas arachidonic, docosatetraenoic and docosahexaenoic acids were much decreased.(5) In spite of the changes in fatty acid composition each of the three phospholipid classes maintained its particular level of unsaturation during EFA deficiency.(6) EPG aldehydes did not change appreciably in deficient conditions.

PLATELET PHOSPHOLIPIDS AND THEIR FUNCTION IN PATIENTS WITH ISHEMIC HEART DISEASE

Abstract. Platelet factor‐3 activity and availability, platelet phospholipids and their fatty acid and aldehyde composition have been examined in males with non‐acute ischemic heart disease and in a control group. Increased platelet factor‐3 activity was present in platelet‐rich but not in platelet‐poor plasma from the patients. No difference in the increase of activity after exposure of PRP to ADP, kaolin or freezing and thawing three times was observed compared with the controls. Estimated per 10° platelets, increased amounts of ethanolamine glycerides, serine phosphoglycerides, choline phosphoglycerides, sphingomyeline and total lipid phosphorus were found in the patient group. The phospholipid: protein ratio was also increased. Only small changes were observed in the fatty acid pattern of the various phospholipids. A slight decrease in palmitic acid and a slight increase in oleic acid were found in most fractions.

Pathways of fatty acid metabolism in human platelets.

The metabolic fate of (14)C-labeled fatty acids which have been incubated with human platelets, has been traced. The following has been shown. (a) Intact platelets have a considerable capacity to oxidize fatty acids. (b) When tracer amounts of four of the most common fatty acids in normal plasma were incubated with platelets, each showed a distinctive pattern of uptake among neutral lipids and phospholipids. With regard to the latter, it was shown that these distribution patterns were, in most cases, similar to those of the fatty acids found in natural platelet phospholipids. (c) By increasing the time of incubation or the amount of added oleic acid, the distribution of oleic acid uptake between lecithin and other phosphoglycerides was altered so that a larger share was incorporated into the latter. (d) The effects of added lysolecithin or lysoethanolamine phosphoglycerides on oleic acid incorporation into platelet phosphoglycerides are quite variable. At low concentrations, added lysolecithin functions chiefly as a reaction partner for oleic acid. Added adenosine triphosphate and CoASH augment the incorporation of oleic acid into lecithin over a wide range of added lysolecithin (12.5-500 mumoles/liter). At higher concentrations of added lysolecithin, in the absence of ATP and CoASH, oleic acid incorporation into lecithin is considerably reduced. Also, added lysolecithin and lysoethanolamine phosphoglycerides, in the absence of ATP and CoASH, are able, at certain concentrations, to stimulate oleic acid incorporation into all except the serine phosphoglycerides. (e) Platelets appear to have a de novo pathway for renewal of lecithin.

Isolation and identification of phospholipids of bovine rhodopsin

Phospholipids present in digitonin solutions of bovine rhodopsin have been identified and assayed. Digitonin interferes with extraction of lipids by the usual methods; digitonin was therefore removed from the preparation as an ergosterol digitonide, soluble in absolute ethanol but precipitated in 80% ethanol. The supernatant 80% ethanol contained one portion of the phospholipid, mainly choline and ethanolamine phosphoglycerides with traces of serine phosphoglyceride and sphingomyelin. The rhodopsin residue (free from digitonin) was extracted with chloroform-methanol 2:1; this extract contained the rest of the phospholipid, which consisted only of choline and ethanolamine phosphoglycerides. Plasmalogens were not found, but could have decomposed during the procedures.

The alk-1-enyl group content of mammalian myelin phosphoglycerides by quantitative two-dimensional thin-layer chromatography

Myelin phospholipids have been examined by a separation-reaction-separation procedure for two-dimensional thin-layer chromatography on silica gel. After separation in one dimension, alk-1-enyl groups are cleaved by exposure of the plates to HCl fumes. Development in the second dimension quantitatively separates acid-labile and acid-stable phosphoglycerides as well as the aldehydes released from the acid-labile phosphoglycerides. Myelin phospholipids from the central nervous systems of the rhesus monkey, squirrel monkey, ox, and mouse contain 32-36% acid-labile ethanolamine phosphoglycerides (ethanolamine plasmalogens) and 8-14% acid-stable ethanolamine phosphoglycerides. Acid-labile choline and serine phosphoglycerides account for less than 1% of the myelin phospholipids.

The fatty acid and aldehyde composition of the major phospholipids of mouse brain

Phospholipid classes were separated from mouse brain lipid extracts by preparative thin-layer chromatography (TLC). Methyl esters were prepared from the intact phospholipids by direct transesterification at room temperature in the presence of silica gel by using 0.5M: NaOH-methanol in order to prevent interference by aldehydes or derivatives. Dimethyl acetal derivatives of phosphoglyceride alkenyl ethers (alkenyl moiety with a double bond in 1,2-position relative to oxygen linkage) were prepared, using 5% concentrated HCl in methanol, followed by preparative TLC for isolation.The major phospholipids present were ethanolamine phosphoglycerides (EPG) 39.8%, choline phosphoglycerides (CPG) 39.7%, serine phosphoglycerides (SPG) 15.0%, and sphingomyelin (Sph) 5.4%. One-fifth of the total phospholipids (PL) were in the form of plasmalogens, mainly EPG. Choline and serine plasmalogens were present in trace quantities. The major aldehyde components of the plasmalogens were 16ratio0, 18ratio0, and 18ratio1.The EPG were rich in long-chain poly-unsaturated fatty acids, including 28.8% of 22ratio6 and 17.0% of 20ratio4, but contained only 7.2% of 16ratio0. In contrast, the CPG contained 39.6% of 16ratio0, and 31.0% of 18ratio1 with a small content of polyunsaturated fatty acids. The SPG exhibited a still different pattern containing 38.2% of 18ratio0, 23.2% of 18ratio1, 24.3% of 22ratio6, 2.9% of 16ratio0, and 3.8% of 20ratio4.