Isolation of brominated long-chain fatty acids from the phospholipids of the tropical marine spongeAmphimedon terpenensis

Preliminary investigation of the phospholipid fatty acid composition of the tropical marine spongeAmphimedon terpenensis by gas chromatography/mass spectrometry revealed the presence of some novel brominated fatty acids. Two new brominated fatty acids, (5E, 9Z)-6-bromo-5,9-tetracosadienoic acid (2a) and (5E, 9Z)-6-bromo-5,9-pentacosadienoic acid (3a) were subsequently isolated from a chloroform/methanol (3∶1, vol/vol) extract of the sponge and characterized as their methyl esters 2b and 3b. The known brominated fatty acid (5E, 9Z)-6-bromo-5,9-hexacosadienoic acid (4a) was also isolated. The new fatty acid methyl esters were confirmed as brominated δ5,9 acid derivatives by chemical ionization mass spectrometry. The position of the bromine substituent was determined to be C-6 by nuclear magnetic resonance techniques while the stereochemistry of the two double bonds was deduced by nuclear Overhauser enhancement difference spectroscopy. The biosynthetic implications of the co-occurrence of the three brominated acids are discussed.     

The distribution of brominated long-chain fatty acids in sponge and symbiont cell types from the tropical marine spongeAmphimedon terpenensis

The tropical marine spongeAmphimedon terpenensis (family Niphatidae, order Haplosclerida) has previously been shown to possess unusual lipids, including unusual fatty acids. The biosynthetic origin of these fatty acids is of interest as the sponge supports a significant population of eubacterial and cyanobacterial symbionts. The total fatty acid composition of the sponge was analyzed by gas chromatography/mass spectrometry of the methyl esters. Among the most abundant of the fatty acids in intact tissue were 16∶0, 18∶0 and 3,7,11,15-tetramethylhexadecanoic (phytanic) acid. In addition, three brominated fatty acids, (5E,9Z)-6-bromo-5,9-tetracosadienoic acid (24∶2Br), (5E,9Z)-6-bromo-5,9-pentacosadienoic acid (25∶2Br) and (5E,9Z)-6-bromo-5,9-hexacosadienoic acid (26∶2Br) were also present. The three brominated fatty acids, together with phytanic acid, were isolated from both ectosomoal (superficial) and choanosomal (internal) regions of the sponge. Analysis of extracts prepared from sponge/symbiont cells, partitioned by density gradient centrifugation on Ficoll, indicated that phytanic acid and the three brominated fatty acids were associated with sponge cells only. Further, a fatty acid methyl ester sample from intact tissue ofA. terpenensis was partitioned according to phospholipid class, and the brominated fatty acids were shown to be associated with the phosphatidylserine and phosphatidylethanolamine fractions that are commonly present in marine sponge lipids. The phosphatidylcholine and phosphatidylglycerol fractions were rich in the relatively shorter chain fatty acids (16∶0 and 18∶0). The association of brominated long-chain fatty acids (LCFA) with sponge cells has been confirmed. The findings allow comment on the use of fatty acid profiles in chemotaxonomy and permit further interpretation of LCFA biosynthetic pathways in sponges. The assignment of the sponge studied, which is currently placed asA. terpenensis, is being supported to some extent, but the species is unusual in having C₂₅ fatty acids as the major constituent in this group. Other factors, such as season or microenvironmental conditions, may influence observed fatty acid composition which tends to reduce the usefulness of fatty acid profiles as markers in sponge chemotaxonomy.     

Physico-chemical studies on the composition and stability of copper chelates of 2-hydroxystearic and 2-hydroxydocosanoic acids

The complex formation of copper (II) with 2-hydroxystearic and 2-hydroxydocosanoic acids has been investigated at pH 8.0 in a medium ofm-xylene-ethanol (75:25 v/v). The formation of only one complex metal: ligand (1:2) is detected by three independent methods, viz. Job’s method of continuous variation, conductometric titration and chemical analysis of the isolated complexes. The logarithm of the formation constants (log K) as calculated by the method of Turner and Anderson are 6.30 and 5.73 and the free energy change of combination are, −8.590 kcal and −7.814 kcal respectively. A chelate structure for both the complexes, in which the ligand molecules act as a bidentate chelating species involving the weakly coordinating hydroxyl group in bond formation has been suggested by analogy with the copper derivatives of amino acids.     

水溶性藻多糖的提取分离

热水浸提螺旋藻多糖最佳的提取条件为:液料比(mL∶g)=30∶1,提取温度80℃,提取时间4 h,多糖提取率为56.24%。用PFS处理后,提取液的粘度下降了41.1%,杂质絮凝率、脱色率、蛋白质去除率分别达到80.32%,75.48%,50.30%,糖含量保存率为85.40%。处理后提取液再经醇沉复溶,所得的糖纯度为0.89 g/g总固形物。     

2-Hydroxy fatty acids from marine sponges 2. The phospholipid fatty acids of the caribbean spongesVerongula gigantea andAplysina archeri

The α-hydroxy fatty acids 2-hydroxy-eicosanoic (1) acid, 2-hydroxyheneicosanoic (2) acid, 2-hydroxydocosanoic (3) acid, 2-hydroxytetracosanoic (4) acid, 2-hydroxy-23-methyl-tetracosanoic acid and 2-hydroxypentacosanoic (5) acid were isolated from the Caribbean spongesVerongula gigantea andAplysina archeri. The very long chain fatty acids 5,9-nonacosadienoic acid (29∶2) and 5,9,23-tricontatrienoic acid (30∶3) were also identified together with theiso-prenoid fatty acid 3,7,11,15-tetramethylhexadecanoic (phytanic) acid that seems to be common in the Aplysinidae.A. archeri contained an extremely long chain fatty acid tentatively characterized as dotricontaenoic (32∶1) acid. These acids were found to occur in phosphatidylserine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylcholine and traces of phosphatidylglycerol.     

On the isolation of the new fatty acid 6,11-eicosadienoic (20∶2) and related 6,11-dienoic acids from the spongeEuryspongia rosea

The phospholipid fatty acids from the spongeEuryspongia rosea were studied revealing the presence of the new 6,11-eicosadienoic (20∶2) acid and the rare 6,11-octadecadienoic acid (18∶2). The isolation of these 6,11-dienoic acids reveals the presence of new biosynthetic possibilities in sponges and suggests the presence of an active Δ6 desaturase inE. rosea. Other acids isolated fromE. rosea include 12-eicosenoic (20∶1) and 17-tetracosenoic acid (24∶1). The major phospholipids encountered in the sponge were phosphatidylethanolamine (PE), phosphatidylserine (PS), and phosphatidylcholine (PC).     

Terpenes in sponge cell membranes: Cell separation and membrane fractionation studies with the tropical marine spongeAmphimedon sp.

The differing sponge and symbiotic microbial cell types in the tropical marine spongeAmphimedon sp. were fractionated according to density, investigated by electron microscopy, and analyzed by high-performance liquid chromatography and nuclear magnetic resonance for the presence of the terpene metabolite diisocyanoadociane (1) and Δ^5,7-sterols (2–7). A sample of whole sponge was dissected into superficial ectosome and deeper choanosome. The superficial tissue was found to be enriched in sterol relative to choanosome; however, extracts from both tissues contained terpene. Dissociation of whole sponge followed by Ficoll density gradient fractionation showed that there are two chemically distinct types of sponge cells inAmphimedon sp.—small non-nucleolated cells of low density contain terpene 1 together with sterols, while larger nucleolated cells contain significant levels of terpene, but only traces of sterol. Membrane fractionation studies were undertaken to establish whether the terpene components were located specifically in the cell membranes of these two cell types. A membrane vesicle pellet spun down at 100,000×g from small sponge cells contained sterols, but only traces of terpene, whereas the membrane vesicle preparation from heavier cells contained both terpenes and sterols. Subsequently, the presence of terpenes together with sterols was demonstrated in a membrane vesicle preparation of purity >90% prepared from bacteria-free sponge cells. These results provide the first experimental evidence that terpenes are associated with sponge cell membranes, where they may function as structural components. Part of this work has been published in preliminary form (ref. 1)     

New phospholipid fatty acids from the marine spongeCinachyrella alloclada uliczka

The fatty acid composition of phospholipids from the Senegalese spongeCinachyrella alloclada was examined. Two new fatty acids not hitherto found in nature, namely 10,13-octadecadienoic acid and 16-tricosenoic acid, were identified. 8-Hexadecenoic, 13-nonadecenoic and 5,9,13-trimethyltretradecanoic fatty acids were also found for the first time in sponges. The latter compound (1.4% of the total fatty acid mixture), an isoprenoid fatty acid, accompanies the major fatty acid 4,8,12-trimethyltridecanoic acid (19.7%). The monomethyl branched fatty acids (22%) identified include 23-methylpentacosanoic acid (anteiso-26∶0), not previously observed in sponged. The major long-chain fatty acids encountered were the known 17-tetracosenoic 19-heptacosadienoic and 5,9,23-tricontatrienoic acid. Some sixty fatty acids were identified as methyl esters andN-acyl pyrrolidides by gas chromatography and gas chromatography/mass spectrometry.     

15,18,21,24-triacontatetraenoic and 15,18,21,24,27-triacontapentaenoic acids: New C30 fatty acids from the marine spongeCliona celata

The marine sponseCliona celata contains 3.5% 30∶4ω6 and 7.0% 30∶5w3 in its total fatty acids. These C₃₀ polyunsaturated structures are unknown in other living organisms. Both acids occur mainly as phosphatidylserine esters.     

Structure and biosynthesis of novel conjugated polyene fatty acids from the marine green algaAnadyomene stellata

Novel polyunsaturated fatty acids with four conjugated double bonds were found in extracts of the green macroalga,Anadyomene stellata. The isolation of five of these with different chain lengths and varying degrees of unsaturation −16∶5, 18∶4, 20∶5, 20∶6, and 22∶7—was accomplished by organic extraction followed by a combination of vaccum and high-performarce liquid chromatography. One of these that was a novel substance (22∶7) was characterized as 4ZZ,7Z,9E,13Z,16Z,19Z-docosaheptaenoic acid and assigned the trivial name stellaheptaenoic acid. The structure of this new compound, isolated as its methyl ester derivative, was deduced from detailed nuclear magnetic resonance, gas chromatography/mass spectrometry (GC/MS), and other spectroscopic methods. Incubation of a chloroplast preparation, isolated from a crude algal homogenate by differential centrifugation, with six unsaturated fatty acids (palmitoleic, 6Z,9Z,12Z,15Z-octadecatetraenoic acid, arachidonic acid, eicosapentaenoic acid, 7Z,10Z,13Z,16Z-docosatetraenoic acid, and 4Z,7Z,10Z,13Z,16Z,19Z-docosahexaenoic acid) resulted in substantially increased synthesis of unique tetraene compouds as detected by ultraviolet spectrophotometry and tentatively identified by GC/MS.     

Seasonal fat and fatty acids variations of seven marine fish species from the Mediterranean Sea

Seasonal variations of proximate compositions, muscle lipids and fatty acids (FA) of seven seawater species (Silllago sihoma, Upeneus pori, Sparus aurata, Saurida undosquamis, Epinephelus auneus, Mullus barbatus, Solea solea) from the Mediterranean Sea, were determined in all seasons. The results showed that the fatty acid compositions of each species ranged from 26.41 to 38.70% saturated (SFA), 13.78 to 26.52% monounsaturated (MUFAs) and 25.02 to 50.83% PUFAs. The highest proportions of EPA were obtained from M. barbatus (8.34%) in spring, S. sihoma (7.54%), U. pori (6.75%), S. aurata (6.31%), S. undosquamis (5.12%), E. auneus (5.10%) in summer, and also S. solea (6.19%) in spring. The highest proportions of DHA were found in spring, ranging from 25.14% for M. barbatus to 34.87% for S. aurata, except for S. solea (30.44%) in winter and S. sihoma (15.83%) in summer. The results showed that from a quality point of view, all species were suitable for human nutrition, since muscle lipids are rich in EPA + DHA in all seasons. Practical application : The American and Canadian Dietetic Associations recommend two servings of fatty fish per week and a daily combined intake of EPA and DHA of 500 mg. This follows a trend of numerous publications and other guidelines recognizing the health benefits of long‐chain n‐3 PUFA from fish or marine microbial sources with respect to cardiovascular health, neurological diseases, infant health and development, inflammation and cancer and other health effects. The seven species analyzed here provide muscle lipids that are rich in EPA and DHA. Only minor season‐to‐season changes in the total content of n‐3 and n‐6 PUFA were observed for the same species. The results provide valuable information for preparing diet tables.     

Synthesis and isolation of methyl esters ofa-branched acids

A series of esters ofa-branched fatty acids containing 28–38 carbon atoms has been synthesized by free radical-catalyzed addition of saturated aliphatic esters to terminal aliphatic olefins. Methods of purification of methyla-decyloctadecanoate have been studied. The structure of methyla-decyloctadecanoate has been established by nuclear magnetic resonance and by independent synthesis. Presented at AOCS Meeting, Houston, April 1965. E. Utiliz. Res. Dev. Div., ARS, USDA.     

A simple method for the quantitative isolation and resolution of unesterified fatty acids from fats and oils

The unesterified fatty acids (UFA) present in fats and oils are isolated cleanly and without the formation of detectable artifacts due to saponification. The lipid (≤0.5 g) dissolved in 5 ml of n-hexane is passed over a 300-mg bed of Celite impregnated with saturated, aqueous Na₃PO₄ so that the solution passes through the bed in 3–4 min. After the bed has been washed, the UFA are freed from their salts by pumping of HC1 vapor over the bed. The acids are eluted with CH₂Cl₂ and subsequently separated underivatized by gas liquid chromatography. The C₁₀ through C_18.3 acids are separated in <15 min. Recovery of the C₁₀-C_18∶0 and C_18∶1, C_18∶2 and C_18∶3 acids added to fatty acid-free fats and oils in several concentrations was nearly 100%     

Isoprenoid fatty acids from marine sponges. Are sponges selective?

The burrowing spongesAnthosigmella varians andSpheciospongia vesparium were found to be rich in the isoprenoid phospholipid fatty acid 4,8,12-trimethyltridecanoic (5.2% and 23%, respectively, of the total fatty acid composition), while the burrowing spongeChondrilla nucula and the demospongeAgelas dispar contained the acid 3,7,11,15-tetramethylhexadecanoic (13.8% and 8.6%, respectively, of the total phospholipid fatty acid composition). No other isoprenoid fatty acid was found, and the two acids described in this work did not occur concomitantly in the same sponge.     

GC-MS structural characterization of fatty acids from marine aerobic anoxygenic phototrophic bacteria

The FA composition of 12 strains of marine aerobic anoxygenic phototrophic bacteria belonging to the genera Erythrobacter, Roseobacter, and Citromicrobium was investigated. GC-MS analyses of different types of derivatives were performed to determine the structures of the main FA present in these organisms. All the analyzed strains contained the relatively rare 11-methyloctadec-12-enoic acid, and three contained 12-methyl-octadec-11-enoic acid, which has apparently never been reported before. High amounts of the very unusual octadeca-5,11-dienoic acid were present in 9 of the 12 strains analyzed. A FA containing a furan ring was detected in three strains. Analytical data indicated that this FA was 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid. A very interesting enzymatic peroxidation of the allylic carbon 10 of cis-vaccenic acid was observed in three strains. Deuterium labeling and GC-MS analyses enabled us to demonstrate that this enzymatic process involves the initial dioxygenase-mediated formation of 10-hydroperoxyoctadec-11(cis)-enoic acid, which is then isomerized to 10-hydroperoxyoctadec-11(trans)-enoic acid and converted to the corresponding hydroxy-acids and oxoacids. Different biosynthetic pathways were proposed for these different compounds.     

The origin of the marine polyunsaturated fatty acids. Composition of some marine plankton

Summary and Conclusions Shrimp, crabs, the marine diatomNitzschia closterium, Platymonas sp., and the fresh water algaChlorella pyrenoidosa were maintained or cultured in the laboratory. The crustacea were fed low-fat, cottonseed oil, and menhaden oil rations. The fatty acid composition of all groups, as well as that of native phytoplankton and zooplankton catches, were determined as the extinction coeffcients, (E _1% ^1cm. ), at wavelengths of maximum absorption. It was found that both shrimp and crabs lost much of their polyunsaturated acids on the fat-free diet and regained it again by ingestion, as do fish. The shrimp however appeared to synthesize more highly unsaturated acids from cottonseed oil than did other aquatic animals. Phytoplankton do produce a high level of polyunsaturated fatty acids. The importance of the determination of the structure of aquatic plant and animal fatty acids in the problem of the origin of the acids and their mechan ism of synthesis was discussed. Contribution from the Departments of Oceanography and Meteorology and of Biochemistry and Nutrition of the Agricultural and Mechanical College System of Texas, Oceanography and Meteorology Series No. 137; supported in part by Grant No. A-777 from the National Institutes of Health and Grant No. A-020 from the Robert A. Welch Foundation.     

Polymers from 2-oxazolidone and dicarboxylic acids

Summary 2-Oxazolidone was reacted at elevated temperature with adipic, isophthalic or sebasic acid. The reaction products were polymeric in nature and range in color from light tan to dark brown. The polymers were not soluble in most common laboratory solvents with the exception of DMF and DMSO. The polymers had moderate inherent viscosities and ¹H-NMR and infrared spectra consistent with a polyester-amide chain structure.     

The phospholipid fatty acids of the marine spongeXestospongia muta

The rare phospholipid fatty acids 3,7,11-trimethyldodecanoic (1), 5,9-hexadecadienoic (2) and 12-methyl-hexadecanoic (3) were identified in the marine spongeXestospongia muta. Branched fatty acids inX. muta accounted for 35% of the total fatty acid mixture. It was observed that the occurrence of the 5,9-hexadecadienoic acid (2) coincides with the complete absence of the very long chain fatty acid 5,9-hexacosadienoic. The acid 5,9,19-octacosatrienoic seems to be found in mostXestospongia species.     

On the syntheses of triacylglycerols from branched saturated fatty acids

A number of triacylglycerols with branched acyl groups were prepared via 1,2-isopropylidene glycerol for the purpose of studying three different physical properties: gel point, refractive index, and density. The monoacid triacylglycerols were prepared either via the corresponding acids or the acyl chlorides.