Localization of long-chain fatty acids and unconventional sterols in spherulous cells of a marine sponge

Brominated compounds from marine sponges of the genus Aplysina and a compilation of their 13C NMR spectral data

Aplysina is the best representative genus of the family Aplysinidae. Halogenated substances are its main class of metabolites. These substances contribute greatly to the chemotaxonomy and characterization of the sponges belonging to this genus. Due to their pharmacological activities, these alkaloids are of special interest. The chemistry of halogenated substances and of the alkaloids has long been extensively studied in terrestrial organisms, while the number of marine organisms studied has just started to increase in the last decades. This review describes 101 halogenated substances from 14 species of Aplysina from different parts of the world. These substances can be divided into the following classes: bromotyramines (A), cavernicolins (B), hydroverongiaquinols (C), bromotyrosineketals (D), bromotyrosine lactone derivatives (E), oxazolidones (F), spiroisoxazolines (G), verongiabenzenoids (H), verongiaquinols (I), and dibromocyclohexadienes (J). A compilation of their (13)C NMR data is also part of the review. For this purpose 138 references were consulted.

Lectin histochemistry and ultrastructure of microgranular cells in Cinachyra tarentina (Porifera, Demospongiae)

A histochemical study is described that characterizes microgranular cells of the demosponge Cinachyra tarentina (C. tarentina) with the use of routine staining methods for mucosubstances, lectin histochemistry and electron microscopy. Microgranular cells are rare or absent in other species of sponges, but abundant in this species. Microgranular cells are present in both ectosome and mesohyl, particularly along the canal of the aquiferous system and around spicule holes. Inclusions of microgranular cells and the extracellular matrix were particularly positive for acidic glycoproteins with abundant sulfated ester groups and glycosidic residues containing GalNAc and Galbeta1,3GalNAc. Terminal L-fucose bound to the penultimate GalNAc residues and/or difucosylated oligosaccharides were present as well. Our results suggest that soybean lectin (SBA), peanut lectin (PNA), and winged pea lectin (WPA) are valuable markers for identifying microgranular cells of C. tarentina. Electron microscopy revealed some of the microgranular cells to contain small smooth cytoplasmic vesicles originating from the Golgi complex and few electron-dense granules, others were characterized by numerous secretory granules and vacuoles formed by vesicle fusion and connected with the plasma membrane. Our results suggest that microgranular cells in C. tarentina contribute to the synthesis of glycoprotein components of the extracellular matrix.

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

The tropical marine sponge Amphimedon 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-tetramethyl-hexadecanoic (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 ectosomal (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 of A. 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.(ABSTRACT TRUNCATED AT 250 WORDS)

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

Preliminary investigation of the phospholipid fatty acid composition of the tropical marine sponge Amphimedon 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 delta 5,9 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.

Cell separation of Tethya aurantia, an analytical study of embryonic and differentiated sponge cells

The cells of the sponge Tethya aurantia var. californiana were separated on a Ficoll density gradient and the fractions analyzed for cell types and their lipids. Major cell types were choanocyte, archeocyte, and symbiont. Major differences in archeocyte and choanocyte fatty acid composition were noted for 20:4, 26:1 and 26:2. The fatty acids 26:1, 26:2, and 28:3 were dominant in the phosphatidylcholine fraction. Archeocytes had highest concentrations of 4,7,10,13-20:4 and 5,8,11,14-20:4 (arachidonic) acids which could be derived from symbionts, as odd-chain and methyl-branched fatty acid were also present. Sterol analyses showed cholesterol as a major sterol of the sponge cell fractions and clionasterol (or its 24-isomer) as a major sterol in symbiont cells.

Cholesterol interactions with tetracosenoic acid phospholipids in model cell membranes: role of the double-bond position

The synthesis and thermotropic properties of 1,2-di-(9Z)-9-tetracosenoylphosphatidylcholine [delta 9-PC(24:1,24:1), 1], 1,2-di-(5Z)-5-tetracosenoylphosphatidylcholine [delta 5-PC(24:1,24:1), 2], and 1,2-di-(15Z)-15- tetracosenoylphosphatidylcholine [delta 15-PC(24:1,24:1), 3] are reported. Liposomes prepared from these phospholipids differ from those of the natural sponge phospholipids, 1,2-di-(5Z,9Z)-5,9-hexacosadienoylphosphatidylcholine (4a) and the corresponding ethanolamine (4b), both of which virtually exclude cholesterol from their bilayers. The behavior of 1 and 2 is similar to that of 1,2-di-(6Z,9Z)-6,9-hexacosadienoylphosphatidylcholine (5), which exhibits a partial molecular interaction with cholesterol. In the case of 3, cholesterol appears to interact with the saturated acyl chain regions of this phospholipid in a manner similar to that of its interaction with DPPC acyl chains. This study delineates the effect of the double-bond location in long fatty acyl chains of phospholipids on their interactions with cholesterol.