The alkyl moieties in wax esters and alkyl diacyl glycerols of sharks

The alkyl moieties in wax esters and alkyl diacyl glycerols from the liver of the dogfish, soupfin shark, and silky shark are almost exclusively saturated and monounsaturated, the main alkyl moieties being the C(16) and C(18) chains in both lipid classes. However, the alkyl moieties in wax esters occur in a wider range of chain lengths. The unsaturated alkyl moieties in the two classes of lipids are mixtures of isomers. The distribution of isomeric octadecenyl moieties in wax esters and alkyl diacyl glycerols is almost the same.     

Preparation of labeled alkyl acyl glycerophosphorylcholine

A method for the preparation of 1-alkyl 2-acyl glycero-3-phosphorylcholine, labeled in the 2-position with oleic acid-1-(14)C is described. This method, based on the acylation of a 1-alkyl glycero-3-phosphorylcholine-CdCl(2) complex which is, in turn, formed from 1-alk-1-enyl glycero-3-phosphorylcholine by hydrogenation and subsequent reaction with cadmium chloride, offers a relatively simple means of preparing a labeled saturated ether phospholipid suitable for use in metabolic studies.     

Gas-liquid chromatography of hyocholic acid

Partial derivatives of hyocholic acid were formed under the usual conditions for trifluoroacetylation of bile acids (trifluoroacetic anhydride, 35 degrees C for 20 min). Complete trifluoroacetylation of hyocholic acid was achieved at 80 degrees C for 30 min, or at 60 degrees C for 30 min when a trace of pyridine was added to the reaction mixture.     

Phospholipid (diacyl, alkylacyl, alkenylacyl) and fatty acyl chain composition in murine mastocytoma cells

The phospholipids from murine mastocytoma FMA3 and P-815 clone cells were quantitatively analyzed, and the major glycerophospholipids were examined for their fatty acyl chain distribution. In these cells, the content of histamine was less than 1/100 of normal mouse mast cells, and FMA3 cells had 1.5-fold as much histamine content as P-815 cells. The predominant phospholipid species of both mastocytoma FMA3 and P-815 were choline-containing glycerophospholipids (48%) and ethanolamine-containing glycerophospholipids (29%). The remaining minor constituents were sphingomyelin (6%, 7%), phosphatidylinositol (7%, 5%), phosphatidylserine (2%, 5%), cardiolipin (4%, 3%), and phosphatidic acid (2%, 1% for FMA3 and P-815, respectively). The choline-containing glycerophospholipids consisted of high amounts of 1-O-alkyl-2-acyl type (31%, 25%) and 1,2-diacyl type (63%, 66%) and a smaller amount of 1-O-alk-1'-enyl-2-acyl type (7%, 8%). In contrast, ethanolamine-containing glycerophospholipids were characterized by high contents of 1-O-alk-1'-enyl-2-acyl type (36%, 31%) and 1,2-diacyl type (55%, 58%), and a lower level of 1-O-alkyl-2-acyl type (12% and 11% for FMA3 and P-815, respectively). Unlike choline-containing glycerophospholipids and sphingomyelin that were rich in palmitic acid, ethanolamine-containing glycerophospholipids, phosphatidylserine and phosphatidylinositol showed a high proportion of stearic acid in the overall fatty acid composition. The content of arachidonic acid was highest in phosphatidylinositol. Sphingomyelin had a large amount of long chain and polyunsaturated fatty acids. In both choline- and ethanolamine-containing glycerophospholipids, the predominant fatty acids in the sn-1-position were palmitic, stearic, and oleic acid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Archaeal and bacterial glycerol dialkyl glycerol tetraether lipids in hot springs of yellowstone national park

Glycerol dialkyl glycerol tetraethers (GDGTs) are core membrane lipids originally thought to be produced mainly by (hyper)thermophilic archaea. Environmental screening of low-temperature environments showed, however, the abundant presence of structurally diverse GDGTs from both bacterial and archaeal sources. In this study, we examined the occurrences and distribution of GDGTs in hot spring environments in Yellowstone National Park with high temperatures (47 to 83 degrees C) and mostly neutral to alkaline pHs. GDGTs with 0 to 4 cyclopentane moieties were dominant in all samples and are likely derived from both (hyper)thermophilic Crenarchaeota and Euryarchaeota. GDGTs with 4 to 8 cyclopentane moieties, likely derived from the crenarchaeotal order Sulfolobales and the euryarchaeotal order Thermoplasmatales, are usually present in much lower abundance, consistent with the relatively high pH values of the hot springs. The relative abundances of cyclopentane-containing GDGTs did not correlate with in situ temperature and pH, suggesting that other environmental and possibly genetic factors play a role as well. Crenarchaeol, a biomarker thought to be specific for nonthermophilic group I Crenarchaeota, was also found in most hot springs, though in relatively low concentrations, i.e., <5% of total GDGTs. Its abundance did not correlate with temperature, as has been reported previously. Instead, the cooccurrence of relatively abundant nonisoprenoid GDGTs thought to be derived from soil bacteria suggests a predominantly allochthonous source for crenarchaeol in these hot spring environments. Finally, the distribution of bacterial branched GDGTs suggests that they may be derived from the geothermally heated soils surrounding the hot springs.     

Purification of glycerol dialkyl nonitol tetraether from Sulfolobus acidocaldarius

A modified procedure for extraction and purification of hydrolyzed archaebacterial lipids is described. Lipids were extracted from Sulfolobus acidocaldarius using a Soxhlet extraction procedure followed by trichloroacetic acid solvent-extraction of the residue. The yield of total extractable material by this protocol was 14% which, after a two-phase wash, yielded 10% lipid. Modifications to the published steps for purifying the subsequently hydrolyzed lipids were developed to purify glycerol dialkyl nonitol tetraether (GDNT). The nearly colorless final macrocyclic product was characterized by TLC, IR, NMR, and mass spectrometry.     

2H-NMR comparative study of phosphocholine group conformation in bilayers composed of diacyl and dialkyl phosphatidylcholines

Model membranes formed from 1,2-dihexadecyl-, 1,2-dipalmitoyl-, 1,2-ditetradecyl- or 1,2-dimyristoyl-rac-glycero-3-phosphocholine, deuterium-labelled at choline groups, in an excess of water were compared using 2H-NMR spectroscopy. The dynamics and conformation of the labelled choline segments were estimated based on spin-lattice relaxation time and residual quadrupole splittings. The trimethylammonium group of dialkyl phosphatidylcholine was shown to be more distant from the bilayer surface as compared with that of the diacyl analogues.     

Gas-liquid chromotography of trimethylsilyl and alkyl oxime-trimethylsilyl derivatives of some prostaglandins

TMS (trimethylsilyl), MO-TMS (methyl oxime-TMS), and EO-TMS (ethyl oxime-TMS) derivatives of several prostaglandins (A, B1, B2, E1, 8-iso-E1, E2 and 8-iso-E2) were prepared and their gas chromatographic properties examined on a moderately polar (OV-17) and a relatively non-polar (SE-30) stationary phase. Combined gas chromatography-mass spectrometry (GC-MS) using an LKB 9000 instrument was used to identify the different derivatives. Although the TMS derivatives are more easily prepared, the TMS derivatives of the PgE series are thermally somewhat unstable. Thus, MO-TMS and EO-TMS derivatives which exhibit more regular retention increments are more useful for analytical work. The EO-TMS derivatives may be useful in determining mass spectral fragmentation modes of the prostaglandin derivatives.     

Hormonal control of diacyl glycerol mobilization from fat body of the desert locust,Schistocerca gregaria

The action of adipokinetic hormone in stimulating mobilization of diacyl glycerol from locust fat body was studied in vitro. For optimum lipid mobilization haemolymph protein and calcium ions were required, and the amount and time course of release were dependent on the hormone concentration. Dibutyryl cyclic AMP or theophylline mimicked the action of the hormone and a synergistic effect of theophylline with hormone was found. Purified adipokinetic hormone with theophylline increased the concentration of cyclic AMP in fat body and stimulated the incorporation of [³H]-adenine into cyclic AMP.A lipase was present in fat body extracts which hydrolysed triacyl glycerol mainly to diacyl glycerol plus fatty acid. The activity of this enzyme was low, and attempts to activate it with hormone were unsuccessful.     

Distribution of intact and core membrane lipids of archaeal glycerol dialkyl glycerol tetraethers among size-fractionated particulate organic matter in hood canal, puget sound

There is great interest in the membrane lipids of archaea (glycerol dialkyl glycerol tetraethers [GDGTs]) as tracers of archaeal biomass because of their utility as paleoproxies and because of the biogeochemical importance of archaea. While core GDGTs (formed by hydrolysis of polar head groups of intact GDGTs after cell death) are appropriate for paleostudies, they have also been used to trace archaeal populations. Also, despite the small size (0.2 by 0.7 μm) of cultivated marine archaea, 0.7-μm glass-fiber filters (GFFs) are typically used to collect GDGTs from natural waters. We quantified both core and intact GDGTs in free-living (0.2- to 0.7-μm), suspended (0.7- to 60-μm), and aggregate (>60-μm) particle size fractions in Puget Sound (Washington State). On average, the free-living fraction contained 36% of total GDGTs, 90% of which were intact. The intermediate-size fraction contained 62% of GDGTs, and 29% of these were intact. The aggregate fraction contained 2% of the total GDGT pool, and 29% of these were intact. Our results demonstrate that intact GDGTs are largely in the free-living fraction. Because only intact GDGTs are present in living cells, protocols that target this size fraction and analyze the intact GDGT pool are necessary to track living populations in marine waters. Core GDGT enrichment in larger-size fractions indicates that archaeal biomass may quickly become attached or entrained in particles once the archaea are dead or dying. While the concentrations of the two pools were generally not correlated, the similar sizes of the core and intact GDGT pools suggest that core GDGTs are removed from the water column on timescales similar to those of cell replication, on timescales of days to weeks.     

Gas-liquid chromatography for the determination of acetylcholinesterase activity

Method has been modified and used for quantitative gas chromatographic determination of microtraces in a large volume of test mixture under study. The method can be applied for the differentiated determination of genuine and false blood cholinesterase by final products of specific substrate hydrolysis.     

Altered acyl chain compositions of alkylacyl, alkenylacyl, and diacyl subclasses of choline and ethanolamine glycerophospholipids in rat heart by dietary fish oil

The effects of dietary fish oil containing n - 3 polyunsaturated fatty acids on the fatty acid compositions of the alkylacyl and alkenylacyl species of choline glycerophospholipids (CGP) and ethanolamine glycerophospholipids (EGP) were studied in rat heart and compared with the corresponding diacylglycerophospholipids. After a 7 week feeding period, all phospholipid classes from the fish oil group exhibited much higher levels of the n - 3 polyunsaturated fatty acids including eicosapentaenoic acid (20:5(n - 30)), docosapentaenoic acid (22:5(n - 3)) and docosahexaenoic acid (22:6(n - 3)), as well as lower levels of the n - 6 series (18:2, 20:4, 22:4 and 22:5), relative to animals given sunflower seed oil-enriched in 18:2(n - 6). However, the docosahexaenoic acid rather than eicosapentaenoic acid provided a much greater contribution to the n - 3 accumulation (fish oil group) in the ether-containing CGP, as indicated by the 20:5(n - 3)/22:6(n - 3) molar ratios of 0.32, 0.26 and 0.56 in the alkylacyl, alkenylacyl and diacyl classes, respectively. In addition to accumulating very high levels of docosahexaenoic acid (e.g., 47.2 mol% of fatty acids in alkenylacylglycerophosphoethanolamine of fish oil group), both ether-linked classes of EGP exhibited significantly higher levels of docosapentaenoic acid than the diacylglycerophosphoethanolamine (GPE) and all classes of CGP. These findings may bear relevance to possible beneficial effects of dietary fish oil on pathophysiological states (including myocardial ischemia) in cardiac tissue and their mediation via platelet-activating factor, 1-alkyl-2-acetylglycerophosphocholine (PAF) and arachidonic acid (20:4(n - 6))-derived eicosanoids.