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8 páginas, 2 figuras., There is increasing evidence of the importance of herbivory in seagrass communities, but the factors that regulate seagrass–herbivore interactions remain largely unknown. Many terrestrial plants and marine algae chemically deter herbivores using secondary metabolites, yet their incidence and role on seagrasses have received little attention. Posidonia oceanica, the dominant seagrass in the Mediterranean Sea, suffers a high level of herbivory and produces phenolics, a type of compounds known to deter feeding in algae and terrestrial plants. We have experimentally quantified the chemical deterrence of P. oceanica against 3 types of sympatric consumers by comparing feeding on palatable agar-based foods containing aqueous and organic extracts of P. oceanica at natural concentrations with that on appropriate controls. The effect of plant chemistry was measured on the feeding of the sea urchins Spharechinus granularis, Paracentrotus lividus and Arbacia lixula, the mesograzer gastropod Cerithium vulgatum, and the general fish assemblage inhabiting P. oceanica meadows. Since these 5 experiments were run independently, we used meta-analysis to test the overall hypothesis that P. oceanica is chemically defended against multiple consumers and to compare the magnitude of their inhibition. Our results clearly showed that the seagrass extracts significantly deterred feeding, although inhibition varied between consumers. S. granularis was the most deterred organism, while the mesograzer C. vulgatum was the only species unaffected by P. oceanica extracts. These results represent the first experimental evidence for seagrass chemical deterrence against a range of consumers, and emphasise the potential importance of chemically mediated interactions between seagrass and herbivores., This work was supported by Grant REN- 2002-04020-C02 from the Spanish Ministry of Science and Education.

In the present paper one population of the “large” subtidal mollusc Cerithium vulgatum Bruguiere, 1792 (Gastropoda: Cerithiidae) from the Northwestern coast of Sicily was investigated from a karyological point of view. The chromosome complement was Giemsa stained, conventionally karyotyped in 18 homomorphic chromosome pairs (10 bi-armed and 8 mono-armed), and subsequently analysed using silver, CMA3 and DAPI staining, and fluorescent in situ hybridization (FISH) with three repetitive DNA probes [ribosomal DNA (rDNA), (TTAGGG)n and (GATA)n]. FISH with the rDNA probe consistently mapped major ribosomal sites (18S-28S rDNA) in the terminal region of the short arms of one small sized mono-armed chromosome pair. Ribosomal DNA was transciptionally active as indicated by its preferential impregnation with silver nitrate (Ag-NOR) and did not contain a high amount of GC base pairs as suggested by the lack of a bright CMA3 fluorescence. The (TTAGGG)n telomeric probe was hybridized to the termini of nearly all chromosomes, thus demonstrating that, in C. vulgatum, this sequence has been conserved during the genomic evolution. The finding of the telomeric hexanucleotide in six species belonging to the three high taxa of Gastropoda supports the notion that this sequence is widespread within this class. The (GATA)n probe did not label any chromosome regions except for a minute terminal area of a single bivalent at pachytene stage.

Şahin, Yeşim Müge (Arel Author), Biphasic bioceramic nanopowders of hydroxyapatite (HA) and ß-tricalcium phosphate (TCP) were prepared from shells of the sea snail Cerithium vulgatum (Bruguière, 1792) using a novel chemical method. Calcination of the powders produced was carried out at varying temperatures, specifically at 400°C and 800°C, in air for 4 hours. When compared to the conventional hydrothermal transformation method, this chemical method is very simple, economic, due to the fact that it needs inexpensive and safe equipment, because the transformation of the aragonite and calcite of the shells into the calcium phosphate phases takes place at 80°C under the atmospheric pressure. The powders produced were determined using infrared spectroscopy (FT-IR), X-ray diffraction, and scanning electron microscopy (SEM). The features of the powders produced along with the fact of their biological origin qualify these powders for further consideration and experimentation to fabricate nanoceramic biomaterials.

© 2014 Elsevier Ltd. The Banded dye-murex (Hexaplex trunculus), the main component of the Purple dye, was one of the most valued marine resources in Roman times. Its ancient exploitation appears described in the written sources. Until now, the archaeological record documenting the industry of Purple dye consisted of middens of broken shells that only allowed the identification of the harvested species and the derivation of some 14C dates, while the identity of the fishing methods used remained elusive. An integrated study of a zooarchaeological assemblage recovered at the Roman city of Pollentia (Mallorca, Western Mediterranean) has thrown light on this unknown aspect of the muricid gastropod fishery. I present sound evidence supporting that at this Roman site, the gastropod Cerithium vulgatum was used at least during the 3rd century AD as bait to collect the Banded dye-murex. This is derived from the high frequency of drilled shells - especially of shells showing incomplete drills - recorded in the deposit, suggesting that these specimens were unnaturally over-exposed to predatory gastropods. This is exactly what could be expected if these cerithids were encased as bait in traps used to collect muricids., This research is included in the Research Projects CGL2012-38087 and HAR2009-08290/HIST funded by the Direccion General de Investigación, Ministerio de Ciencia y Tecnología (Madrid). The author had a JAEPredoc fellowship from the Consejo Superior de Investigaciones Científicas of the Ministerio de Educacion y Ciencia of Spain

In the digestive glands of gastropod molluscs, metals are metabolized in the sense that they are subject to inorganic biochemical processes within the epithelial cells and lumen of the digestive tubules and the pore cells in the intervening connective tissue. These systems have been examined in the tower shell Cerithium vulgatum Bruguieres, a sediment feeder, the top shell Monodonta articulata Lam., a grazing herbivore, and in the whelk Murex trunculus L., a carnivore whose prey includes Cerithium . These animals were taken from a Mediterranean environment polluted by heavy metals. In all three species the metals are compartmentalized within mineralized granules as phosphates and within lysosomal residual bodies in association with sulphur. However, the extent to which a particular metal is accumulated and the relative proportions that are bound within the different compartments are factors that are primarily determined by the species and not the concentration available in the environment. Thus Cerithium accumulates high concentrations of a wide range of metals from the ingested sediment and these are rendered insoluble and non-toxic in the digestive gland. This unavailability is transferred to Murex when it eats Cerithium because Murex does not accumulate the full range of metals from its prey. Indeed, for some metals there appears to be bioreduction rather than bioamplification. The grazing herbivore Monodonta articulata accumulates a third distinct spectrum of metals. The accumulations in each species do not reflect the levels of all the metals in the environment. The presence of metals in the digestive glands is associated with the removal of magnesium from the phosphate granules but also with an increase in the concentration of magnesium in the tissue. It is proposed that metals induce the formation of magnesium phosphate as a source of metal-binding phosphate ions.