Opisthobranch molluscs from the subtidal trawling grounds off Blanes (Girona, north-east Spain)

7 páginas, 4 tablas, 3 figuras.Studies on the opisthobranch molluscs inhabiting the continental platform in areas not accessible by SCUBA diving are rare in the subtidal bottoms of the Iberian Peninsula. Data obtained from trawls are not adequate for quantitative analysis, due to the indirect method used and the high number of variables which a¡ect the capture of the samples. However, with the aim of obtaining qualitative information on the opisthobranch molluscs inhabiting the subtidal trawling grounds o¡ Blanes, we took more than 500 samples over a two-year period, on the non-commercial fraction of the trawling fisheries, finding opisthobranchs in 306 samples. We analysed samples from 16 trawling sites, at depths between 50 and 300m, by using ten fishing boats of the ‘Confraria de Pescadors del Port de Blanes’. We obtained 4.295 specimens of opisthobranchs belonging to 29 species. From these, 4 are Cephalaspidea s.s., 1 Anaspidea, 1 Umbraculacea, 3 Pleurobranchacea and 20 Nudibranchia (3 Arminina, 3 Dendronotina and 14 Doridina). The most abundant species were Gastropteron rubrum and Scaphander lignarius, both cephalaspideans present during all seasons, and the dendronotaceanTethys ¢mbria. For Scaphander lignarius it was possible to distinguish three size-groups, from which the smallest one was usually found in summer. Other interesting species found were, among others, Armina tigrina, Baptodoris cinnabarina, Thordisa filix and Kaloplocamus ramosus. The richest trawling grounds in species numbers and abundances were La Planassa and Els Capets. The total number of opisthobranch species reported for the trawling grounds off Blanes is now 48.This study is part of the project Fauna Ibe¤rica V (subproject Mollusca, Opisthobranchia DGSIC PB98-0532) of the Science Ministry of Spain.Peer reviewe

Molluscan natural products as biological models: chemical ecology, histology, and laboratory culture

The utility of some natural products from molluscs has been known for centuries. However, only recently have modern technologies and advances in the fields of chemistry, chemical ecology, anatomy, histology, and laboratory culture allowed the exploitation of new, unprecedented applications of natural products. Recent studies have dealt with (a) the role that these compounds have in the sea in protecting the animals (e.g., chemical defense), or in mediating their intraspecific communication (e.g., pheromones), (b) the geographical differences in similar or related species (and the implications of this in chemical ecology and phylogeny), and (c) the localization of these metabolites in molluscan tissues (by means of the most modern technologies), among others. The methodology for the laboratory culture of some species has also been established, thus offering new insights into this interesting field. Further applications of all these challenging studies are currently being developed.Peer reviewe

Chemotaxis in the nudibranch Hermissenda crassicornis: Does ingestive conditioning influence its behaviour in a Y-maze?

Este artículo contiene 8 páginas, 3 tablas.The nudibranch mollusc Hermissenda crassicornis can be cultured easily in the laboratory and has been used as a biomedical model for learning and memory studies. Cultured animals whose only prey was Tubularia crocea were tested for responses to other prey. Naive slugs were conditioned with six different diets and tested for behaviour in a Y-maze. H. crassicornis was able to detect chemotactically food items which it had never been in contact with (such as Pennaria), but it did not detect some of the conditioning diets (e.g. Metridium). At least three hydroid species induce a chemotactic behaviour in the slug. It is shown that ingestive conditioning does affect their response in single-choice and double-choice experiments. As food items other than cnidarians are also detected, it is likely that different Wairomones are responsible for the nudibranch's behaviour.Peer reviewe

Catálogo preliminar de substancias naturales de moluscos opistobranquios del Mediterráneo occidental y Atlántico próximo

10 páginas, 1 figura, 1 tabla.[EN] A list of opisthobranch molluscs species from the western Mediterranean and nearby Atlantic is presented. These species have natural products that are of interest because of their chemical structure, origin and/or function in benthic ecosystems. This review contains data on the origin and activity of these molecules, collection sites of the animals, and their bibliographic references. A discussion of these subjects is also included.[ES] Se presenta un listado de especies de moluscos opistobranquios del Mediterráneo occidental y Atlántico próximo, que poseen substancias naturales de interés por su estructura química, su origen y/o su función en ecosistemas bentónicos. Se incluyen datos sobre el origen y la actividad de estas substancias, los lugares de procedencia de los animales estudiados, las referencias bilbiográficas relacionadas, así como una discusión sobre los mismos.This work has been supported by F.I. fellowship from the Generalitat de Catalunya and is part of the author's doctoral thesis. Financial support of the C.I.C.Y.T. from the Spanish Government is also acknowledged (MAR 91-0528).Peer reviewe

Chemical ecology of the nudibranch Glossodoris pallida: Is the location of diet-derived metabolites important for defense?

The nudibranch mollusc Glossodoris pallida possesses the diet-derived terpenoid compounds scalaradial, desacetylscalaradial, and deoxoscalarin. In this study, we determined whether the compounds were located strategically in the nudibranch body for defense against predators, as well as whether they were present in mucus secreted by the nudibranch. Analysis of the distribution of metabolites in the different body parts indicated an accumulation of compounds in the border of the mantle (where the mantle dermal formations are located), as well as in the mucus secretion. Several experiments were conducted in order to establish a relationship between the location of the compounds and the chemical defense of the nudibranch, using artificial diets as well as animals with and without the borders of their mantles. The compounds from the mantle border deterred feeding by crabs (Leptodius spp.) and reef fishes when tested at their natural concentrations. When the mantle borders were removed from some nudibranchs, these animals were significantly more susceptible to predation by reef fishes than were animals with their mantle borders intact. While we were able to demonstrate that the diet-derived compounds in the mantle border function in the defense of the nudibranch, both in the laboratory against the crabs and in the field against natural assemblages of predatory reef fishes, our experiments with artificial diets did not indicate that the location of the compounds was critical for defense. Food cubes with pieces of mantle border tissue or extracts of mantle border tissue distributed uniformly throughout the cubes or along one border were equally effective at deterring feeding by reef fishes relative to control cubes. The location of diet-derived compounds in the mantle borders may also serve other functions in addition to defense.Peer reviewe

The growth of Peltodoris atromaculata Bergh, 1880 (Gastropoda: Nudibranchia) in the laboratory

The growth of Peltodons atromaculata Bergh, 1880, measured as total dorsal body area, was followed in the laboratory for 15 months. The growth of dorsal brown patches was compared to the total area of the mantle, and was shown to be approximately constant over time in the different animals. This numerical approach can be useful to quantify the body pigmentation cline previously described for Mediterranean specimens. P atromaculata has an annual life-cycle in the laboratory, reaching its maximum size before opposition. Post-spawning mortality followed a decrease in size for all specimens. Mantle margin autotoray in P atromaculata seems not to be related to defence against predation, but it is a process that takes place before death in laboratory.Peer reviewe

A new tritoniid species (Mollusca : Opisthobranchia) from Bouvet Island

9 páginas, 6 figuras, 3 tablasTritoniid sea slugs (Mollusca, Gastropoda, Opisthobranchia) are reported for the first time from Bouvet Island. Tritonia dantarti sp. n. shows morphological and anatomical differences with regard to the two previously known tritoniids reported from Antarctica and Sub-Antarctica, Tritonia vorax (Odhner 1926) and Tritonia challengeriana Bergh, 1884. Regarding the external morphology, T. dantarti sp. n. is characterized by a very bright orange coloration in the dorsum, white dorsal crests, highly ramified dendritic gills (the largest vertically orientated and the rest laterally orientated), and a quadrangular cross section. The radula presents very long, thin lateral teeth and the jaws present mainly unicuspidate, striated denticles. The seminal receptacle is large, pear-shaped and its grey pigmentation differs from the rest of the genital system. The Antarctic species T. challengeriana was also found in waters off Bouvet Island, while the Subantarctic species T. vorax was not found.We are thankful for the support of the ECOQUIM projects (REN2003-00545 and REN2002-12006-E ANT).Peer reviewe

The Phylum Bryozoa as a Promising Source of Anticancer Drugs

Special Issue Antitumor Compounds from Marine Invertebrates.-- 23 pages, 2 figures, 1 tableRecent advances in sampling and novel techniques in drug synthesis and isolation have promoted the discovery of anticancer agents from marine organisms to combat this major threat to public health worldwide. Bryozoans, which are filter-feeding, aquatic invertebrates often characterized by a calcified skeleton, are an excellent source of pharmacologically interesting compounds including well-known chemical classes such as alkaloids and polyketides. This review covers the literature for secondary metabolites isolated from marine cheilostome and ctenostome bryozoans that have shown potential as cancer drugs. Moreover, we highlight examples such as bryostatins, the most known class of marine-derived compounds from this animal phylum, which are advancing through anticancer clinical trials due to their low toxicity and antineoplastic activity. The bryozoan antitumor compounds discovered until now show a wide range of chemical diversity and biological activities. Therefore, more research focusing on the isolation of secondary metabolites with potential anticancer properties from bryozoans and other overlooked taxa covering wider geographic areas is needed for an efficient bioprospecting of natural productsB.F. was supported by a Juan de la Cierva-incorporación Postdoctoral Fellow (IJCI-2017-31478). Support for this work was provided by a BLUEBIO grant to C.A. (CTM2016-78901/ANT)Peer Reviewe

The Understudied Phylum Bryozoa as a Promising Source of Anticancer Drugs

Preprint Figuerola, Blanca; Àvila, Conxita. The Phylum Bryozoa as a Promising Source of Anticancer Drugs. Marine Drugs 17(8): 477 (2019). doi: 10.3390/md17080477Recent advances in sampling and novel techniques in drug synthesis and isolation have promoted the discovery of anticancer agents from marine organisms to combat this major threat to public health worldwide. Bryozoans, filter-feeding, sessile aquatic invertebrates often characterized by a calcified skeleton, are an excellent source of pharmacologically interesting compounds including well-known chemical classes such as alkaloids and polyketides. This review covers the literature for secondary metabolites isolated from marine cheilostome and ctenostome bryozoans that have shown potential as cancer drugs. Moreover, we highlight examples such as bryostatins, the most known class of marine-derived compounds from this animal phylum, which is advancing through anticancer clinical trials due to their low toxicity and antineoplastic activity. The bryozoan antitumour compounds discovered until now show a wide range of chemical diversity and biological activities. Therefore, more research focusing on the isolation of secondary metabolites with potential anticancer properties from bryozoans and other overlooked taxa covering wider geographic areas is needed for an efficient bioprospecting of natural productsPeer reviewe

Histology of epithelia and mantle glands of selected species of doridacean mollusks with chemical defensive strategies

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