C. Devijver

5-Hydroxytryptamine-Derived Alkaloids from Two Marine Sponges of the Genus Hyrtios

Indonesian specimens of the marine sponges Hyrtios erectus and H. reticulatus were found to contain 5-hydroxytryptamine-derived alkaloids. Their structures were determined on the basis of their spectral properties. H. erectus contained hyrtiosulawesine (4), a new beta-carboline alkaloid, together with the already known alkaloids 5-hydroxyindole-3-carbaldehyde (1), hyrtiosin B (2), and 5-hydroxy-3-(2-hydroxyethyl)indole (3). H. reticulatus contained the novel derivative 1,6-dihydroxy-1,2,3,4-tetrahydro-beta-carboline (11) together with serotonin (5), 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-beta-carboline (7), and 6-hydroxy-3,4-dihydro-1-oxo-beta-carboline (9).

Primary cultures from the marine sponge Xestospongia muta (Petrosiidae, Haplosclerida)

In the context of the investigations on the origin and in vitro production of bioactive compounds, primary cultures were developed from ectosomal and choanosomal cell suspensions from the sponge Xestospongia muta. Dissociated cells aggregated and reorganized into a striking reticulated network of cells, typical for X. muta. Moreover, in some cultures an isotropic reticulation of small spicules, very similar to that found in the ectosome of adult sponges, was observed. Phytohaemagglutinin promoted aggregation and the reorganization of the cells. HPLC analyses revealed that straight-chain acetylenic compounds were recovered from short-term cultures and that they were synthesized during culture. Heterotrophic bacteria were assumed to be involved in the process. Together our results established that X. muta would be an excellent experimental model to study, in laboratory conditions, the differentiation of the skeleton and the in vitro biosynthesis of straight-chain acetylenic compounds.

Preliminary Ecological Studies on Sponges of the Genus Agelas Spp.

The influence of environmental factor, namely depth and sponge-coral interactions as well as the effects of infliction of standardized damages on the production of bromopyrrolic alkaloids isolated from the sponges Agelas dispar and Agelas conifera were analysed.

Preliminary Antifungal Activity of Some Sponges from Indonesia and Oman

80 methanolic extracts from sponges of Indonesia and Oman were screened for antifungal activity against ten strains fungi: Botrytis cinerea, Cladosporium cucumerinum, Fusarium oxysporum, Penicillium expansum, Rhizopus oryzae, Trichoderma harzianum, Aspergillus niger, Mucor pusillus, Absidia corymbifera and Absidia ramosa. The bromopyrrolic alkaloids hymenidin and sceptrin isolated from the sponges Agelas dispar and Agelas conifera, respectively, were also tested against the above fungi.

Biosynthesis of tetraponerine-6. Evidence that two different pathways are operating in the biosynthesis of the two tetraponerine skeletons

Evidence is presented showing that tetraponerine-6 2a from Tetraponera sp. ants is biosynthesized from two molecules of putrescine and a seven-carbon moiety coming from an eight-carbon polyacetate chain through decarboxylation, in contrast with tetraponerine-8 1a, which derives from one putrescine unit and a twelve-carbon polyacetate precursor.