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Fractionation of cytotoxic extracts of specimens of a newly described sponge genus, Candidaspongia, has yielded the candidaspongiolides (3), a complex mixture of acyl esters of a macrolide related to tedanolide. The general structure of the candidaspongiolides was determined by analyses of various 2D NMR and MS data sets. The acyl ester componentswere identified by GC-MS analysis of the derived fatty acid methyl esters. The mixture could be selectively converted to the deacylated macrolide core (4) by enzymolysis with immobilized porcine lipase, with the structure of the candidaspongiolide core then secured by NMR and MS analysis. The candidaspongiolide mixture was potently cytotoxic, exhibiting a mean panel 50% growth inhibition (GI50) of 14 ng/mL in the National Cancer Institute’s 60-cell-line in Vitro antitumor screen.

The sterol chemistry of 21 species of sponges from the orders Haplosclerida and Petrosida (Porifera: Demospongiae) was examined and compared, and the results analyzed using cluster analysis and ordination. Replicate samples within some species were examined statistically to determine if variability of sterol complements was constant within a species. The results of this study did not support separation of sponge species into the two orders, Haplosclerida and Petrosida, on the basis of sterol complements. While previous analyses of species within the Petrosida revealed the presence of unconventional sterol cyclopropenes and cyclopropanes, no such sterols were found in the petrosid sponges we examined. Species within the same families failed to group on the basis of sterol chemistry, suggesting either their taxonomic allocations at this level are incorrect, or sterol complement is not a useful feature at this taxonomic level. Some species within the same genus grouped together while others did not. Sterol complements of species remained constant irrespective of geographic locality or season collected. Sponge species have both a qualitative and quantitative sterol fingerprint. The data set provided evidence of a species complex within Xestospongia muta . Three specimens of this species contained significantly different sterol complements.

A phenethylammonium salt of a new steroid sulfate, echinoclasterol sulfate (1) has been isolated from the marine sponge, Echinoclathria subhispida. The structure was determined by interpretation of spectral data including 2D NMR and FABMS. It exhibited antifungal activity against Mortierella ramannianus, and cytotoxicity against PC-9 human lung cancer cells.

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 Δ5,7-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.

α1,3-Fucosyltransferase (Fuc TVII) is a key enzyme in the biosynthesis of selectin ligands. We have isolated two inhibitors of Fuc TVII from a marine sponge Sarcotragus sp. They were characterized as octa- and nonaprenylhydroquinone sulfates on the basis of spectral data. These compounds inhibited Fuc-TVII with IC50 values of 3.9 and 2.4 μg/mL, respectively.

Six new diterpene isocyanides have been isolated from a sponge ( Adocia sp.). Their structures support the biosynthetic suggestion for the formation of diisocyanoadociane reported from the same sponge.

Five new quinones have been isolated from a sponge tentatively classified as Stelospongia conulata. Isospongiaquinone (7) has a rearranged drimane skeleton whereas spongiaquinone (19), cyclo- spongiaquinone-1 (20), cyclospongiaquinone-2 (21) and dehydrocyclospongiaquinone-1 (22) have a normal drimane skeleton. The structures of these were derived from chemical and spectral evidence.

The sponge Pseudaxinyssa sp., unique in sterol and fatty acid composition, was cellularly dissected into fractions enriched in each of the major cell types present in the sponge: microbial symbionts (cyanobacteria), small sponge cells (pinacocytes and choanocytes), and large sponge cells (archeocytes and cyanophytes). Three phototrophic microbial symbionts were also isolated from the cell fractions and grown in culture. An unsymmetrical distribution of fatty acids and sterols was observed for the sponge cells: small cells contained larger quantities of long chain fatty acids (greater than C24) and smaller quantities of sterols than were present in the larger sponge cells. Moreover, the rare sterols 24-isopropylcholesterol predominated in the smaller sponge cells, whereas its 22-dehydro analog predominated in the larger sponge cells. Long chain fatty acids and sterols were not detected in the cultured microbial symbionts. This constitutes the first report of lipid variability according to cell type for this most primitive group of Metazoa.

4-Amino-5-bromopyrrolo[2,3-d]pyrimidine has been isolated from a sponge (Echinodictyum sp.). The pharmacologically active constituent of the red alga Hypnea valendiae has been identified as 4-amino-7-(5'-deoxyribos-1'β-yl)-5-iodopyrrolo[2,3-d]pyrimidine (7). A second nucleoside, tentatively assigned as the 1'α isomer of (7), has also been isolated.

Five new quinones have been isolated from a sponge tentatively classified as Stelospongia conulata. Isospongiaquinone (7) has a rearranged drimane skeleton whereas spongiaquinone (19), cyclo- spongiaquinone-1 (20), cyclospongiaquinone-2 (21) and dehydrocyclospongiaquinone-1 (22) have a normal drimane skeleton. The structures of these were derived from chemical and spectral evidence.

Eight new sesquiterpenes, (ll), (12), (14)-(16), (18), (20) and (21), have been isolated from four separate small collections of the sponge Dysidea herbacea. The structures of these compounds, all of which contain a furan group, were derived by comparison of their spectral properties with those of known sesquiterpenes.

Five new scalarane sesterterpenes have been isolated from a Western Australian sponge (Lendenfeldia sp.). As with earlier reported examples of these compounds, several of these metabolites of this sponge are extremely potent inhibitors of platelet aggregation.

Seven novel metabolites, each originating from four bromotyrosine units, have been isolated from the sponge Ianthella basta. Bastadin-1 (2), bastadin-2(3) and bastadin-3(4) are derived from a single phenol oxidative coupling whilst the macrocyclic compounds bastadin-4(5), bastadin-5(6), bastadin-6(8) and bastadin-7(7) are formed by two phenol oxidative coupling reactions. Compounds (2)-(8) showed potent in vitro antimicrobial activity against Gram-positive organisms.