Haemagglutination activity of lectins from extracts of some Vietnam marine sponges

Aqueous extracts from 16 species of Vietnam marine sponges were examined for haemagglutination activity using native and enzyme-treated different animal and human erythrocytes. Among these, extracts from 14 species were found to have haemagglutinination activities toward at least one type of erythrocyte tested meaning that 87.5% of the surveyed marine sponge species possess haemagglutination activity. Strong activity was detected in extracts from marine sponge species Acanthella cavernosa, Axinyssa sp., Cinachyrella sp., 01NT.2.4, 3.5, 3.10, 3.11 and 3.18 with enzyme-treated various animal and human erythrocytes. In a haemagglutination–inhibition test with various monosaccharides and glycoproteins, haemagglutination activity of the extract from A. cavernosa had no affinity for any of the monosaccharides, but inhibited by porcine stomach mucin and fetuin, whereas activities of the extract from Cinachyrella sp. were strongly inhibited by monosaccharides, such as D-galactose and N-acetyl-D-galatosamine, but not with glycoproteins. The activity of Stylissa flexibilis extract was inhibited by D-galactose, porcine stomach mucin, fetuin and their asialo derivatives, suggesting the presence of lectin specific for O-glycans of this species. The activities of four sponge extracts from A. cavernosa, S. flexibilis, Axinyssa sp. and Cinachyrella sp. were stable over a wide range of pH and temperature. Haemagglutination activities of A. cavernosa, Axinyssa sp. and Cinachyrella sp. extracts were independent of the presence of divalent cations, except for the haemagglutination activity of extract from S. flexibilis, which was dependent on the presence of divalent cations. The results suggest that Vietnam marine sponges may be good sources of useful lectins for biochemical and biomedical applications.

Impact of the Cultivation Technique on the Production of Secondary Metabolites by Chrysosporium lobatum TM-237-S5, Isolated from the Sponge Acanthella cavernosa

The fungi Chrysosporium lobatum TM-237-S5 was isolated from the sponge Acanthella cavernosa, collected from the mesophotic coral ecosystem of the Red Sea. The strain was cultivated on a potato dextrose agar (PDA) medium, coupling solid-state fermentation and solid-state extraction (SSF/SSE) with a neutral macroreticular polymeric adsorbent XAD Amberlite resin (AMBERLITE XAD1600N). The SSF/SSE lead to high chemodiversity and productivity compared to classical submerged cultivation. Ten phenalenone related compounds were isolated and fully characterized by one-dimensional and two-dimensional NMR and HRMS. Among them, four were found to be new compounds corresponding to isoconiolactone, (-)-peniciphenalenin F, (+)-8-hydroxyscleroderodin, and (+)-8-hydroxysclerodin. It is concluded that SSF/SSE is a powerful strategy, opening a new era for the exploitation of microbial secondary metabolites.

A comparison of prokaryote communities inhabiting sponges, bacterial mats, sediment and seawater in Southeast Asian coral reefs

In the present study, we used Illumina sequencing to explore the prokaryote communities of 17 demosponge species and how they compare with bacterial mat, sediment and seawater samples (all sampled from coral reef habitat in Taiwan and Thailand). The studied sponge species formed three clusters. OTU richness and evenness were by far highest in the sediment and bacterial mat biotopes. There were pronounced differences in OTU richness and evenness among clusters and also considerable variation among certain host species within clusters. Additionally, the relative abundance of some prokaryotic taxa also differed among clusters with Poribacteria, for example, being recorded in all sponge species, but with very low relative abundances in species of two of the three clusters. This sponge-associated phylum was, however, recorded at relatively high mean abundance in bacterial mat samples, which also housed relatively high abundances of actinobacterial and Chloroflexi members. Our results support the HMA status of the species Aaptos lobata, Hyrtios erectus, Pseudoceratina purpurea and Xestospongia testudinaria, which clustered together and LMA status of the species Acanthella cavernosa, Echinodictyum asperum, Jaspis splendens, Ptilocaulis spiculifer, Stylissa carteri and Suberites diversicolor, which also clustered together. Other species (Agelas cavernosa, Agelas nemoechinata, Acanthostylotella cornuta, Paratetilla sp., Hymeniacidon sp. and Haliclona cymaeformis) deviated somewhat from the typical HMA/LMA dichotomy and formed a strongly supported cluster.

Cytotoxic Nitrogenous Terpenoids from Two South China Sea Nudibranchs Phyllidiella pustulosa, Phyllidia coelestis, and Their Sponge-Prey Acanthella cavernosa

A detailed chemical investigation of two South China Sea nudibranchs Phyllidiella pustulosa and Phyllidia coelestis, as well as their possible sponge-prey Acanthella cavernosa, led to the isolation of one new nitrogenous cadinane-type sesquiterpenoid xidaoisocyanate A (1), one new naturally occurring nitrogen-containing kalihinane-type diterpenoid bisformamidokalihinol A (16), along with 17 known nitrogenous terpenoids (2–15, 17–19). The structures of all the isolates were elucidated by detailed spectroscopic analysis and by the comparison of their spectroscopic data with those reported in the literature. In addition, the absolute stereochemistry of the previously reported axiriabiline A (5) was determined by X-ray diffraction (XRD) analysis. In a bioassay, the bisabolane-type sesquiterpenoids 8, 10, and 11 exhibited cytotoxicity against several human cancer cell lines.