Occurrence of ceramide digalactoside as the main glycosphingolipid in the marine sponge Halichondria japonica.

The main glycosphingolipid of the sponge Halichondria japonica was isolated and its structure was determined to be ceramide digalactoside, Gal alpha 1----4Gal beta 1----1Cer, using FAB/MS, IR, 1H-NMR and chemical methods such as permethylation analysis and degradation techniques. The ceramide moiety was composed mainly of 4-hydroxy-iso-octadecasphinganine and 2-hydroxy-docosanoic acid. Interestingly, the branched long-chain bases were comprised of 70% total long-chain bases and 17.5% 4-hydroxy-anteiso-nonadecasphinganine. Ceramide monohexoside, consisting of galactosyl ceramide (81%) and glucosyl ceramide (19%), was also isolated as a minor component. The composition of the ceramide moiety was nearly the same as that of ceramide digalactoside.

Two novel phospholipid fatty acids from the Caribbean sponge Geodia gibberosa.

The novel fatty acids (Z)-6-nonadecenoic acid (1) and (Z)-17-pentacosenoic acid (2) were characterized in the sponge Geodia gibberosa. These fatty acids were mainly found in phosphatidylethanolamine and phosphatidylcholine.

Mechanism of inotropic action of xestoquinone, a novel cardiotonic agent isolated from a sea sponge.

Xestoquinone (XQN) isolated from the sea sponge Xestospongia sapra produced dose-dependent cardiotonic effects on guinea pig left and right atria. A direct action of XQN (1-30 microM) on the contractile machinery of cardiac myofilaments was demonstrated in chemically skinned fiber preparations from guinea pig papillary muscles. In atrial preparations, the XQN-induced inotropic effect was markedly inhibited by verapamil or nifedipine, but was not affected by practolol, chlorpheniramine, cimetidine, tetrodotoxin or reserpine. The Ca++ dependence curve for the contractile response of the atria was substantially shifted to the left by XQN (10 microM), and this XQN-induced shift was reversed by verapamil. The time-to-peak tension and relaxation times of the atrial contractions were shortened by XQN, and the action potential duration was markedly prolonged. Whole-cell patch clamp recordings in left atrial strips confirmed that XQN (30 microM) increased the slow inward current. However, there was a temporal dissociation between altered tension development and prolongation of the action potential duration. Cyclic AMP phosphodiesterase activity was inhibited and tissue cyclic AMP content of guinea pig left atria was increased by XQN (0.3-10 microM) in a concentration-dependent manner, but increases in cyclic AMP content did not occur in parallel with increases in contractile response. These observations suggest that an enhancement of intracellular cyclic AMP content and Ca++ influx across the cell membrane contribute to the late phase of XQN-caused cardiotonic responses, whereas the early phase may largely be elicited through direct activation of contractile elements. XQN may provide a novel leading compound for valuable cardiotonic agents.

Xestoquinone, a novel cardiotonic agent activates actomyosin ATPase to enhance contractility of skinned cardiac or skeletal muscle fibers.

Xestoquinone (XQN), a novel cardiotonic principle from the sea sponge Xestospongia sapra, enhanced Ca+(+)-induced tension development of chemically skinned fibers from guinea pig cardiac muscle, even at both free Ca++ concentrations as low as -log molar free Ca++ (pCa) 9 to 8. In skinned fibers from guinea pig skeletal muscle, XQN (10 microM) also increased developed tension with a similar Ca++ dependence to that for cardiac fibers. In contrast to the unique Ca+(+)-dependence of XQN effects, the reference drug sulmazole enhanced Ca+(+)-induced tension development of skinned cardiac fibers at pCa 6.6 but did not affect it at pCa 8. In natural actomyosin from canine cardiac muscle, as well as in that from rabbit skeletal muscle, XQN (1-30 microM) enhanced the rate and extent of superprecipitation. Moreover, XQN produced a concentration-dependent increase in the myofibrillar ATPase activity of canine cardiac muscle, even at very low free Ca++ concentrations below the normal threshold for ATPase activation (pCa 9-8). The natural actomyosin ATPase activity of chicken smooth muscle was not influenced by XQN (up to 30 microM). In cardiac myofibrils, no significant difference was observed between the bound 45Ca+(+)-pCa relationship curves in the presence and absence of XQN (10 microM). Furthermore, XQN (30 microM) did not cause or potentiate Ca+(+)-induced Ca++ release from cardiac sarcoplasmic reticulum vesicles. These observations suggest that XQN directly activates actomyosin ATPase activity of cardiac and skeletal myofibrils, thus producing an enhanced superprecipitation activity as well as an increase in skinned fiber contractility.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and characterization of cell adhesion molecules from the marine sponge, Ophlitaspongia tenuis.

Previous studies suggested that cell adhesion in the marine sponge, Ophlitaspongia tenuis, is mediated by a 35 kDa cell surface protein which interacts with an extracellular sulfated polysaccharide. This paper describes a simple and efficient procedure for isolating both putative cell adhesion molecules from detergent lysates of O. tenuis cells, the procedure being based on the fortuitous affinity of the sponge polysaccharide for heparin. The purified polysaccharide inhibits O. tenuis sponge cell aggregation, is highly sulfated and represents a glycosaminoglycan containing glucuronic acid. N-sulfated glucosamine and, possibly, glucose. The purified 35 kDa protein has a high affinity for the sponge polysaccharide and also, selectively interacts with dextran sulfate, a polysaccharide that has been shown previously to both bind to the sponge cell surface and inhibit aggregation of O. tenuis cells. Collectively, the data supports the hypothesis that the 35 kDa molecule is the major cell adhesion protein in O. tenuis. Preliminary data also suggests that the sponge contains an endogenous glycan hydrolase which can cleave the sponge polysaccharide.

Identification and characterization of two new methylicosadienoic acids from Erylus formosus.

The novel fatty acids 18-methyl-5,9-icosadienoic acid [1] and 19-methyl-5,9-icosadienoic acid [2] were identified in the Caribbean sponge Erylus formosus. Other interesting fatty acids identified were the branched acids 3-methylpentadecanoic acid and 3-methylhexadecanoic acid, which are known to possess larvicidal activity. The most stable conformation of the new acid 19-methyl-5,9-icosadienoic acid is also presented as predicted by Molecular Mechanics (MM2) calculations. The sterol composition of E. formosus is also reported.

Anthelmintic polyfunctional nitrogen-containing terpenoids from marine sponges.

The study of the anthelmintic terpenoid components from the Fiji sponge Axinyssa fenestratus (senior synonym of Leucophloeus fenestratus) and two Thailand sponges, Acanthella cavernosa and Topsentia sp., has yielded several new nitrogen-containing sesqui- and diterpenes of known carbon skeletons. Amorphane sesquiterpenes from A. fenestratus included (1R, 6S, 7S, 10S)-10-isothiocyanato-4-amorphene [(+)-1] and new metabolites (1R*, 4S*, 6R*, 7S*)-4-isothiocyanato-9-amorphene [2], 10-isothiocyanato-4,6-amorphadiene [3], and (4S*, 10S*)-10-isothiocyanato-5-amorphen-4-ol [4]. The amorphene (+)-1 of this study may be antipodal to (-)-1 previously isolated from a Hawaiian sponge. A similar relationship may exist at C-1, C-6, C-7 between (+)-2 of this study and (-)-11 isolated from a Palauian sponge. Another known sesquiterpene, axisonitrile 3 [5] was obtained from Topsentia sp. The diterpenes obtained from A. cavernosa included known kalihinols X [6] and Y [8] and new kalihinols J [7] and I [9]. Those terpenoids with potent antiparasite activity include 1, 2, 3-5, and 7-9.

Identification of the new 11,15-icosadienoic acid and related acids in the sponge Amphimedon complanata.

The total phospholipid fatty acids from the Caribbean sponge Amphimedon complanata were studied, revealing the presence of the new 11,15-icosadienoic acid [1], the rare 7-methyl-6-hexadecenoic acid [2], and the recently discovered 6,11-icosadienoic acid. These acids were mainly encountered in phosphatidylethanolamine and phosphatidylcholine.

Diterpenes from the Pohnpeian marine sponge Chelonaplysilla sp.

Nine diterpenes have been isolated from the marine sponge Chelonaplysilla sp. collected in Pohnpei, Federated States of Micronesia. These include the known diterpenes 1-bromo-8-ketoambliol A acetate, dendrillolide A, dendrillolide D, norrisolide, 12-desacetoxyshahamin C, and aplyviolene. Three novel rearranged spongian diterpenes, chelonaplysins A, B, and C, were identified by interpretation of spectral data and chemical correlation with known compounds. Aplyviolene, chelonaplysin B, and chelonaplysin C exhibited antimicrobial activity against the bacterium Bacillus subtilis. The secondary metabolite composition of this collection of Chelonaplysilla sp. is compared to the composition previously reported for samples from Palau.

New avarone and avarol derivatives from the marine sponge Dysidea cinerea.

Six new avarol and avarone derivatives, 3'-hydroxyavarone [3], 3',6'-dihydroxyavarone [4], 6'-hydroxyavarol [5], 6'-acetoxyavarol [6], 6'-acetoxyavarone [7], and 6'-hydroxy-4'-methoxyavarone [8], are reported from the Red Sea sponge Dysidea cinerea. The structures of the new compounds were determined by spectroscopic data, mainly 1D and 2D nmr measurements. The absolute configurations of 5, 6, and 7, and most likely also of 3, 4, and 8, were established on the basis of cd measurements to be the same as that of avarol. Several of the new compounds are cytotoxic, possess antimicrobial activities, and have anti-HIV-1 reverse transcriptase activities; the most active is compound 8.

[Further characterization of the orange carotenoid protein extracted from the marine demosponge Axinella verrucosa]. / Ulteriore caratterizzazione della carotenoproteina arancio estratta dalla demospongia marina Axinella verrucosa.

The orange coloration of the marine sponge A. verrucosa is provided by some carotenoids widespread in the ectosome and mesohyl of this sponge. These carotenoids are bound to a glyco(lipo)protein forming a non covalent complex. Six carotenoids are bound to the glyco(lipo)protein, but only alpha-carotene was identified by HPLC. The aminoacid composition is quite different from those previously reported in Porifera. The content of Ser and Gly and the total polar residues are high. The presence of Met and Pro was not evidenced. Some unusual aminoacids were detected, of which only Taurine was probably identified.

Identification of naturally occurring trans, trans delta 5,9 fatty acids from the sponge Plakortis halichondroides.

The first trans fatty acids from a sponge have been isolated from Plakortis halichondroides. The sponge was shown to contain the iso acids (5E,9E)-19-methyl-5,9-eicosadienoic, (5E,9E)-20-methyl-5,9-heneicosadienoic and (5E,9E)-21-methyl-5,9-docosadienoic acid, as well as the anteiso acids (5E,9E)-19-methyl-5,9-heneicosadienoic and (5E,9E)-20-methyl-5,9-docosadienoic acid together with the straight chain (5E,9E)-5,9-docosadienoic acid. The acids were shown by gas chromatography, Fourier transform infrared and 13C nuclear magnetic resonance to contain the trans configuration. An eicosadienoic acid, namely (6E,14E)-6,14-eicosadienoic acid, and 12-methyl-5-octadecenoic acid were also identified in a sponge for the first time. The fatty acids were shown to be the principal constituents of phosphatidylethanolamine and phosphatidylcholine. No sterols were found in the sponge. The results presented in this work should be helpful in taxonomy of Homoscleromorpha.

Cytotoxic metabolites from the sponge Ianthella basta collected in Papua New Guinea.

Two new cytotoxic metabolites, bastadin 8 [1] and bastadin 9 [2], have been isolated from the marine sponge Ianthella basta collected in Papua New Guinea.

Marine natural products. XXIII. Three new cytotoxic dimeric macrolides, swinholides B and C and isoswinholide A, congeners of swinholide A, from the Okinawan marine sponge Theonella swinhoei.

Following the characterization of swinholide A (1), the major cytotoxic dimeric macrolide, three new congeneric dimeric macrolides, named swinholide B (2), swinholide C (3) and isoswinholide A (10), have been isolated from the Okinawan marine sponge Theonella swinhoei. The structures of these dimeric macrolides have been elucidated on the basis of chemical and physicochemical evidence. These dimeric macrolides were shown to exhibit potent cytotoxicities toward KB cell lines.

cDNA structure and expression of calpactin, a peptide involved in Ca2(+)-dependent cell aggregation in sponges.

Aggregation of cells of the marine sponge Geodia cydonium is mediated by an aggregation factor (AF) particle of Mr 1.3 X 10(8). It is now reported that the AF particle is associated with calpactin, which was ascribed a role in the cell-adhesion process. In order to identify the sequence similarity to other members of the lipocortin family, the cDNA of sponge calpactin was cloned and found to display an 80% sequence similarity to vertebrate calpactin II but only a 47% similarity to calpactin I. The calpactin gene, which contains the consensus sequence coding for the amino acids G-T-D-E, was expressed in Escherichia coli and subsequently purified to a 37000-Mr polypeptide. Both the p32 and the p37 are provided with approximately two Ca2+ ions/molecule and the property to bind to phospholipids. The dissociation constant (calpactin-Ca2+) was in the absence of phospholipids in the range 500-700 microM-Ca2+ but in their presence about 20-30 microM-Ca2+. On the basis of (i) inhibition studies with antibodies to calelectrin and (ii) competition experiments with soluble phospholipids (both chemically defined as well as total homologous membrane lipids) we conclude that the AF-associated calpactin and plasma-membrane-bound phospholipid(s) are involved in cell-cell aggregation in sponges.

The inhibition of human immunodeficiency virus type 1 reverse transcriptase by avarol and avarone derivatives.

We have analyzed the effects of several natural compounds related to avarols and avarones on the catalytic functions of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). The most potent substances, designated as avarone A,B and E and avarol F, inhibited indiscriminately the enzymatic activities of HIV-1 RT, namely the RNA-dependent and DNA-dependent DNA polymerase as well as the ribonuclease H. The inhibition of the DNA polymerase activity was found to be non-competitive with respect to either the template-primer or the deoxynucleotidetriphosphate. These studies suggest that the hydroxyl group at the ortho position to the carbonyl group at the quinone ring is involved in blocking the RT activity. The identification of the active site of the inhibitors will hopefully lead to the rational design of new potent anti-HIV drugs.

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.

Novel marine sponge amino acids, 10. Xestoaminols from Xestospongia sp.

The study of the anthelminthic components from a Fiji sponge Xestospongia sp. has yielded new amino alcohols, xestoaminols A-C. Xestoaminol B, (2S*)-aminotetradeca-11, 13-dien-(3R*)-ol [2], is isomeric to known Xestospongia products, (2S)-aminotetradeca-5,7-dien-(3R)-ol [6] and (2S)-aminotetradeca-5,7-dien-(3S)-ol [7], recently reported by Gulavita and Scheuer. Xestoaminols A [1] and C [3] are, respectively, the dihydro and tetrahydro derivatives of xestoaminol B. A combined nmr and molecular mechanics study on the oxazolidinone of xestoaminol A provided the basis for the relative stereochemistry assigned at C-2 and C-3 in xestoaminol A. This compound was extremely active in assays testing for action against parasites, microbes, and reverse transcriptase.

Identification of the new 18-hexacosenoic acid in the sponge Thalysias juniperina.

The phospholipid fatty acids from the sponge Spheciospongia cuspidifera were studied revealing the presence of the rare 10-octadecenoic acid (10-18:1) and a new 2-methoxyhexadecenoic acid. The phospholipid fatty acids from Thalysias juniperina were also studied revealing the presence of the hitherto unreported 18-hexacosenoic acid (18-26:1). These results tend to indicate that the biosynthetic pathway from 10-18:1 to 18-26:1 may be operative in nature. The phospholipid mixture from the sponges was also analyzed by 31P-NMR and shown to mainly consist of phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and phosphatidylglycerol. Phosphatidylcholine was not found in the sponges analyzed in this work.