Trihydroxy Long-chain Bases Research Articles

Lipidome and metabolome analysis of fresh tobacco leaves in different geographical regions using liquid chromatography-mass spectrometry.

The combination of the lipidome and the metabolome can provide much more information in plant metabolomics studies. A method for the simultaneous extraction of the lipidome and the metabolome of fresh tobacco leaves was developed. Method validation was performed on the basis of the optimal ratio of methanol to methyl tert-butyl ether to water (37:45:68) from the design of experiments. Good repeatability was obtained. We found that 92.2% and 91.6% of the peaks for the lipidome and the metabolome were within a relative standard deviation of 20%, accounting for 94.6% and 94.6% of the total abundance, respectively. The intraday and interday precisions were also satisfactory. A total of 230 metabolites, including 129 lipids, were identified. Significant differences were found in lipidomic and metabolomic profiles of fresh tobacco leaves in different geographical regions. Highly unsaturated galactolipids, phosphatidylethanolamines, predominant phosphatidylcholines, most of the polyphenols, amino acids, and polyamines had a higher content in Yunnan province, and low-unsaturation-degree galactolipids, triacylglycerols, glucosylceramides with trihydroxy long-chain bases, acylated sterol glucosides, and some organic acids were more abundant in Henan province. Correlation analysis between differential metabolites and climatic factors indicated the vital importance of temperature. The fatty acid unsaturation degree of galactolipids could be influenced by temperature. Accumulation of polyphenols and decreases in the ratios of stigmasterols to sitosterols and glucosylstigmasterols to glucosylsitosterols were also correlated with lower temperature in Yunnan province. Furthermore, lipids were more sensitive to climatic variations than other metabolites.

Sphingophosphonolipids, phospholipids, and fatty acids from Aegean jellyfish Aurelia aurita.

The goal of this study is to elucidate and identify several sphingophosphonolipids from Aurelia aurita, an abundant but harmless Aegean jellyfish, in which they have not previously been described. Total lipids of A. aurita were 0.031-0.036% of fresh tissue, and the lipid phosphorus content was 1.3-1.7% of total lipids. Phosphonolipids were 21.7% of phospholipids and consisted of a major ceramide aminoethylphosphonate (CAEP-I; 18.3%), as well as three minor CAEP (II, III, IV) methyl analogs at 1.3, 1.1, and 1.0%, respectively. The remaining phospholipid composition was: phosphatidylcholine, 44.5%, including 36.2% glycerylethers; phosphatidylethanolamine, 18.6%, including 4.5% glycerylethers; cardiolipin, 5.6%; phosphatidylinositol, 2.6%; and lysophosphatidylcholine, 5.0%. In CAEP-I, saturated fatty acids of 14-18 carbon chain length were 70.8% and were combined with 57.3% dihydroxy bases and 23.4% trihydroxy bases. The suite of the three minor CAEP methyl analogs were of the same lipid class based on the head group, but they separated into three different components because of their polarity as follows: CAEP-II and CAEP-III differentiation from the major CAEP-I was mainly due to the increased fatty acid unsaturation and not to a different long-chain base, but the CAEP-IV differentiation from CAEP-I, apart from fatty acid unsaturation, was due to the increased content of hydroxyl groups originated from both hydroxy fatty acids and trihydroxy long-chain bases. Saturated fatty acids were predominant in total (76.7%), polar (83.0%), and neutral lipids (67.6%) of A. aurita. The major phospholipid components of A. aurita were comparable to those previously found in a related organism (Pelagia noctiluca), which can injure humans.

Tissue specificity of glycosphingolipids as expressed in pancreas and small intestine of blood group A and B human individuals

A chemical investigation has been done on blood group active glycosphingolipids of both small intestine and pancreas from two individuals, one blood group A and one blood group B. Total non-acid glycolipid fractions were prepared and the major blood group fucolipids present were purified and structurally characterized by mass spectrometry, proton NMR spectroscopy, and degradation methods. The glycolipid structures identified were a blood group Le b hexaglycosylceramide, a B-hexaglycosylceramide with a type 1 (Galβ1 → 3GlcNAc) carbohydrate chain, A-hexaglycosylceramides with types 1 and 2 (Galβ1 → 4GlcNAc) carbohydrate chains, a B-heptaglycosylceramide with a type 1 carbohydrate chain, and A-heptaglycosylceramides with type 1 and 2 carbohydrate chains. In addition several minor glycolipids having more than seven sugar residues were detected by thin-layer chromatography. The small intestine and pancreas had some distinct differences in their expression of the major fucolipids. The small intestine contained only glycolipids based upon type 1 carbohydrate chain while the pancreas had both type 1 and type 2 structures. The intestines contained mainly difucosyl compounds while the pancreas tissues contained both mono- and difucosyl glycolipids. Monofucosylglycolipids based on both types 1 and 2 saccharides were present in one pancreas while the other one contained only monofucosylcomponents based on type 1 chain. The ceramides of the intestinal glycolipids were found to be more hydroxylated (trihydroxy long-chain base, hydroxy fatty acids) compared to the pancreas glycolipids (dihydroxy long-chain base, non-hydroxy fatty acids).

Glycolipids of rat large intestine characterization of a novel blood group B-active tetraglycosylceramide absent from small intestine

A novel blood group B-active tetraglycosylceramide has been isolated from rat large intestine. It is probably present only in the epithelial cells. Although the compound was not obtained pure, the structure was conclusively established by mass spectrometry, proton NMR spectroscopy and degradative studies to be Gal pα1→3Gal p(21 αFuc p) β1→4Glc pβ1→1Cer. The ceramide was composed of mainly trihydroxy long-chain base (18:0) and non-hydroxy fatty acids (16:0–24:0). The glycolipid was absent from small intestine.

Fatty acids and long-chain bases of gangliosides of human gastrointestinal mucosa

The fatty acid and long-chain base composition of five major gangliosides from human stomach and small and large intestine mucosa were analyzed with gas chromatography. All the gangliosides greatly resembled each other in the fatty acid pattern. The main fatty acids were C 16:0, C 18:0 and C 24:0. No hydroxy fatty acids could be detected. In all the gangliosides 4-sphingenine was the predominant long-chain base (70–75%). About 15% of the long-chain bases had 20 carbon atoms in their chain. No trihydroxy long-chain bases could be detected.

Distribution of molecular species of sphingomyelins in different parts of bovine digestive tract

Sphingomyelins were isolated from mucosal layers of bovine rennet stomach, duodenum, jejunoileum, and colon ascendens. The ceramides obtained after phospholipase degradation were characterized by thin-layer chromatography, mass spectrometry, and gas-liquid chromatography. The main ceramide group from all regions consisted of dihydroxy long-chain bases and normal fatty acids. Sphingosine was the predominant base in all these fractions, and only in rennet stomach were smaller amounts of the C17 and C20 homologs present. Normal saturated C16, C18, C22, and C24 fatty acids were most abundant. In rennet stomach there was in addition a ceramide group having dihydroxy long-chain bases in combination with hydroxy fatty acids. Sphingosine was the predominant long-chain base and the fatty acids were 2-hydroxy C16, C22, C23, and C24. From jejunoileum three minor ceramide fractions were isolated; these consisted of phytosphingosine and normal fatty acids C22-C24), sphingosine and 2-hydroxy fatty acids (C16-C24), and phytosphingosine and 2-hydroxy fatty acids (C22-C24), respectively. No branched paraffin chains were found in significant amounts. Sphingomyelins with trihydroxy long-chain bases and 2-hydroxy fatty acids found in jejunoileum were also detected in bovine kidney and have not been demonstrated before. These sphingomyelins from both kidney and jejunoileum showed a preferential combination of trihydroxy bases and fatty acids with very long chains (C22-C24).

Occurrence of phosphonosphingolipids in Bdellovibrio bacteriovorus strain UKi2.

The major phospholipids of two strains of Bdellovibrio bacteriovorus were characterized. Both strain UKi1, which is obligately saprophytic, and strain UKi2, which is facultatively parasitic, contained phosphatidylethanolamine and phosphatidylglycerol as their major glycerophosphatides. A branched, 15-carbon fatty acid is the major component of these alkali-labile lipids. Absent from UKi1 but present in UKi2 were three alkali-stable lipids (compounds 8, 9, and 11) which appear to be phosphosphingolipids. After acid hydrolysis, both compound 8 and 9 yield the identical phosphorus-containing substance that is water soluble, dipolar ionic, and ninhydrin positive. This substance appears to contain a C-P bond since P(i) could not be released from this substance by treatment with alkaline phosphatase or by very harsh mineral acid treatment. Based on chromatographic comparisons, this phosphonate appears to be a novel lipid constituent. Upon degradation, compound 8 yields 1 mol of dihydroxy long-chain base and compound 9 yields 1 mol of a trihydroxy long-chain base. These bases appear to have a 17-carbon, possibly branched, structure based on gas-liquid chromatography retention times. Degradation of both sphingolipids yields a mixture of hydroxy fatty acids, the major component being a branched, 15-carbon hydroxy acid.

Separation of monoglycosylceramides (cerebrosides) of bovine kidney into subgroups and characterization by mass spectrometry

Monoglycosylceramides of bovine kidney have been separated on columns of borate-impregnated silica gel G into six fractions homogeneous on thin-layer plates. The lipophilic components were identified by mass spectrometry of trimethylsilyl ethers of intact lipids, and the carbohydrate identified by gas chromatography after degradation. Dihydroxy and trihydroxy long-chain bases, normal and 2-hydroxy fatty acids, and glucose and galactose were the components of eight possible combinations. Two of these made up 90 % of the total weight, namely glucosylceramide with trihydroxy base and hydroxy fatty acid, and galactosylceramide with dihydroxy base and hydroxy fatty acid.

Mass spectra of trimethylsilyl derivatives of homogeneous cerebrosides (monoglycosylceramides)

Mass spectra of trimethylsilyl derivatives of a series of homogeneous cerebrosides have been recorded. The compounds studied had a d-galactopyranose in β-glycosidic linkage to different ceramides (containing dihydroxy or trihydroxy long-chain base and normal or hydroxy fatty acid). The composition of some fragments was established by high resolution analysis. Molecular ions were found for all compounds ( m/e 863–1265). Fragments of the silylated hexose were of relatively low intensity (at m/e 451, and 451 minus trimethylsilanol at m/e 361). Specific fragments of medium intensity were obtained from primary cleavage of the long-chain base and of a hydroxy fatty acid. Two rearrangement ions were specific for the fatty acid. Fragments of the base plus fatty acid were also obtained. Trimethylsilyl derivatives should therefore be useful in the analysis of long-chain bases and fatty acids and combinations thereof in natural mixtures of cerebrosides.

Mass spectra of acetyl derivatives of homogeneous cerebrosides (monoglyco-sylceramides)

Mass spectra of acetyl derivatives of a series of homogeneous cerebrosides have been recorded. The compounds studied had a D-galactopyranose in β-glycosidic linkage to different ceramides (containing dihydroxy or trihydroxy long-chain base and normal or hydroxy fatty acid). The composition of the major fragments was established by high resolution analysis. Molecular ions were found for all compounds ( m/ e 713–1055). Dominating fragments were obtained from the acetylated glycose residue, with a similar pattern as for acetylated simple carbohydrates. Fragments containing base plus fatty acid were of medium intensity and may be used for the analysis of natural compounds containing a mixture of fatty acids and long-chain bases. Specific fragments of the fatty acid or longchain base were not found, except for some fragments of low intensity containing part of or the complete normal fatty acid.

Trihydroxy long-chain bases in bovine milk sphingomyelin

Trihydroxy long-chain bases in bovine milk sphingomyelin

Thin-layer chromatography of ceramides

Ceramides with mono-, di-, and trihydroxy long-chain bases, and normal (saturated and unsaturated), branched-chain, and 2-hydroxy fatty acids have been analyzed by thin-layer chromatography. In most cases the compounds were also run as acetates. Borate, arsenite, and silver ions were used as complexing agents, and the effects of number, position, and stereochemistry of hydroxy groups, and of unsaturation, were studied. The results are discussed in view of analysis of natural ceramide species.