Isoswinholide B and swinholide K,potently cytotoxic dimeric macrolides from Theonella swinhoei

Chemical investigation of an Indonesian specimen of Theonella swinhoei afforded the new dimeric macrolides isoswinholide B (5) and swinholide K (6), along with the known swinholides A (1), B (2) and D (3) and isoswinholide A (4). Isoswinholide B showed an unprecedented 21/19′ lactonization pattern, while swinholide K included an sp² methylene attached at C-4 and an additional oxymethine group at C-5, whose configuration has been determined through application of J-based configuration analysis. The isolated swinholides (1–6), with the exception of isoswinholide B, showed a cytotoxic activity on HepG2 (hepatocarcinoma cell line) in the nanomolar range.     

Molecular Cloning of Silicatein Gene from Marine Sponge <Emphasis Type="Italic">Petrosia ficiformis</Emphasis> (Porifera,Demospongiae) and Development of Primmorphs as a Model for Biosilicification Studies

In some sponges peculiar proteins called silicateins catalyze silica polymerization in ordered structures, and their study is of high interest for possible biotechnological applications in the nanostructure industry. In this work we describe the isolation and the molecular characterization of silicatein from spicules of Petrosia ficiformis, a common Mediterranean sponge, and the development of a cellular model (primmorphs) suitable for in vitro studies of silicatein gene regulation. The spicule of P. ficiformis contains an axial filament composed of 2 insoluble proteins, of 30 and 23 kDa. The 23-kDa protein was characterized, and the full-length cDNA was cloned. The putative amino acid sequence has high homology with previously described silicateins from other sponge species and also is very similar to cathepsins, a cystein protease family. Finally, P. ficiformis primmorphs express the silicatein gene, suggesting that they should be a good model for biosilicification studies.     

Implementation of a molecular epidemiology approach to human pleural malignant mesothelioma

The carcinogenic effect of asbestos has been reported in the literature since 40 years, and early studies describing the epidemic occurrence of malignant mesothelioma (MM) in asbestos workers, have become a paradigm of occupational cancer research. Research on MM was abandoned for many years since MM was considered as an asbestos-related disease, interesting only from a perspective of disease control and preventive policies. The introduction of new biological endpoints in the epidemiological studies has boosted research in the field, providing new tools for the study of emerging priority in cancer research and in public health. This approach, known as molecular epidemiology has a great potential in the study of MM, contributing to the understanding of susceptibility factors, to the evaluation of cancer risk in people occupationally or environmentally exposed to carcinogens, and to the enhancement of diagnosis and therapy. A comprehensive approach based on the use of banks of biological samples is presented and its advantages discussed here. The application of innovative endpoints, such as oncoproteins in biologic fluids, genetic polimorphisms, or gene function is discussed, and relevant literature reviewed.     

Gold coral (<Emphasis Type="Italic">Savalia savaglia</Emphasis>) and gorgonian forests enhance benthic biodiversity and ecosystem functioning in the mesophotic zone

The twilight or mesophotic zone is amongst the less explored marine regions. In coastal areas, investigations and manipulative experiments on benthic biodiversity and ecosystem functioning at depths up to >50 m have been recently made possible by the progress of SCUBA techniques. In this study, we tested the effects of the presence of a gorgonian forest characterised by a large and dense population of the gold coral Savalia savaglia (Bertoloni 1819) on the benthic biodiversity (nematode species richness, and meiofauna community structure and richness of taxa), trophic guilds state (molluscs) and ecosystem functioning in the surrounding sediments. The S. savaglia colonies create elevated and complex tertiary structures. Our results indicate that the presence of these colonies was associated with a significantly increased deposition of bioavailable substrates and enhanced biodiversity, when compared with soft bottoms at the same depth but without gold corals. The higher biodiversity and altered trophic conditions resulted in higher rates of ecosystem functioning (e.g., higher benthic biomasses). These results suggest that S. savaglia should be particularly protected not only for its specific rarity, endemism and vulnerability but also because it has a prominent role in sustaining high levels of biodiversity and ecosystem functioning in the surrounding benthos of the twilight zone.     

Organism–quartz interactions in structuring benthic communities: towards a marine bio-mineralogy?

Abiotic and biotic factors determine the distribution and structure of marine benthic communities but the processes invoked to explain such patterns are often inadequate. We demonstrate that the presence of quartz grains in sediments inhibits animal colonization on marine soft-bottoms. We suggest that this phenomenon may be related to the oxidant properties of the quartz crystal surface derived by the generation of silicon-based radicals due to water movement. The interaction between organisms and the crystallographic structure of substrata might play a neglected but important role in structuring coastal benthic communities.     

Differential Gene Expression in a Marine Sponge in Relation to Its Symbiotic State

The molecular mechanisms involved in the establishment and maintenance of sponge photosymbiosis, and in particular the association with cyanobacteria, are unknown. In the present study we analyzed gene expression in a common Mediterranean sponge (Petrosia ficiformis) in relation to its symbiotic (with cyanobacteria) or aposymbiotic status. A screening approach was applied to identify genes expressed differentially in symbiotic specimens growing in the light and aposymbiotic specimens growing in a dark cave at a short distance from the illuminated specimens. Out of the various differentially expressed sequences, we isolated two novel genes (here named PfSym1 and PfSym2) that were up-regulated when cyanobacterial symbionts were harbored inside the sponge cells. The sequence of one of these genes (PfSym2) was found to contain a conserved domain: the scavenger receptor cysteine rich (SRCR) domain. This is the first report on the expression of sponge genes in relation to symbiosis and, according to the presence of an SRCR domain, we suggest possible functions for one of the genes found in the sponge-cyanobacteria symbiosis.     

The assessment of DNA from marine organisms via a modified salting-out protocol

We developed a rapid, practical and non-toxic salting-out method for the extraction of DNA from marine organisms, and tested it on two representative species of Porifera and Cnidaria, both living in association with symbiotic zooxanthellae. We tested the efficiency of the protocol by comparing the output of the method for fresh tissue, frozen tissue and tissue stored in ethanol. It proved to be effective for extracting DNA in the case of the methods of preservation considered here, and for obtaining quantities of DNA comparable to those obtained via the traditional approach. The DNA from both species was of good quality. The DNA obtained was amplified by PCR using specific primers for the large ribosomal subunit, allowing the identification of the presence of both the host and symbiont genomes.     

Biosilica deposition in the marine sponge Petrosia ficiformis (Poiret, 1789): the model of primmorphs reveals time dependence of spiculogenesis

Biomineralization is a phenomenon that spreads across all taxonomic kingdoms and has numerous potential applications in biotechnology. Using cell cultures (primmorphs) of Porifera as a model to study biosilicification, we hypothesised that different culture media can modulate siliceous spicule production both quantitatively and qualitatively. Long-term primmorph cultures of Petrosia ficiformis allowed comparing four experimental conditions: (1) natural seawater (SW) medium containing 5 μM silicate as control; (2) SW-Si 120 μM; (3) SW-Fe 5 μM; (4) SW-Si 60 μM Fe 2.5 μM evidencing several patterns of spiculogenesis. Here we have provided the first demonstration of how spiculogenesis processes are time-dependent and how spicules increase in number and size over time. The addition of dissolved silicon and low iron concentrations to the culture media produces larger spicules in greater numbers, affecting the proportions among spicule types as well. In particular, silicate seems to facilitate the production of fusiform oxeas, while iron stimulates the production of strongyloxeas. Considering the key role of spicules in taxonomic studies, our results point out the importance of environmental conditions in skeletal phenotypic plasticity, modulating the norm of reaction of the species.     

Polyhydroxylated sterols from the Indonesian soft coral Sinularia sp. and their effect on farnesoid X-activated receptor

Chemical investigation of the Indonesian soft coral Sinularia sp. resulted in the isolation of three known (1, 2 and 7) and five new (3-6 and 8) sterols, characterized by either 24-methylcholestane or gorgostane skeletons. The stereostructures of the new compounds have been elucidated by application of HR-MS and 2D NMR techniques. The isolated steroids have been evaluated for their interaction with the farnesoid X-activated receptor (FXR) and some of them, including the new compound 3 and gorgosterol (7), showed a consistent antagonistic activity, potentially useful for the treatment of cholestasis. The FXR antagonistic activity of gorgosterol (7) was also supported by gene expression experiments. Our results represent the first evaluation of soft coral steroids for interaction with nuclear receptors and qualify gorgosterol (7) as a new chemotype of FXR antagonist.     

The aquiferous system of two <Emphasis Type="Italic">Oceanapia</Emphasis> species (Porifera,Demospongiae) studied by corrosion casts

The aquiferous systems of two Indopacific Oceanapia species (Oceanapiidae) were studied by corrosion casts: O. amboinensis living in shallow lagoons and O. fistulosa living at the base of the reef slope. Both species show a massive, entirely buried body, emerging from the sediment only by long, completely close fistules. Particularly in O. fistulosa the corrosion casts revealed a complex, grape-like structure of the choanosome organised in anatomical and functional units composed by an incurrent web whose anastomosed meshes are crossed by a central excurrent canal. A system of thin canals connects the two systems giving rise to an area of choanocyte chambers. The corrosion casts revealed that in both species incurrent water penetrates into the sponge body by the fistules and that it is expelled through specialised structures buried in the sediment. This observation is in accordance with field experiments performed on O. fistulosa. In some specimens of this species, a solution of china ink injected into plastic bags enveloping the external fistules was observed, after waiting for a while, to flow through the buried structures.