Fouling resistance investigations of seaweed products / Investigações de resistência à incrustação de produtos de algas marinhas

Any solid, unprotected, and undefended surface in the aquatic environment will be fouled. Fouling, on the other hand, can affect a wide range of species that can tolerate some epibiosis. Several others, on the other hand, aggressively keep the epibionts off their body surface (antifouling). Antifouling defenses are built into marine plants like seaweed and seagrass. They do have a distinctive surface structure with tightly packed needle-like peaks and antifouling coverings, which may hinder settling bacteria's ability to cling. Chemical antifouling resistance is most probably a biological reaction to epibiosis' ecological drawbacks, especially for organisms capable of performing photosynthesis. The goal of this study was to see how effective natural compounds derived from littoral seaweeds were in preventing fouling. The brown mussel, an important fouling organism, was evaluated in laboratory bioassays against fifty-one populations' crude organic extracts including fort-two macroalgae species. Antifouling activity, exhibited a distinct phylogenetic pattern, with red macroalgae having the largest share of active species, subsequently brown macroalgae. Antifouling action in green seaweeds has never been significant. Seven species showed some level of induced antifouling defense. Our findings appear to back up previous findings about secondary metabolite synthesis in seaweeds, indicating that in the hunt for novel antifoulants, researchers should concentrate their efforts on tropical red macroalgae.

Resumo contaminada. A incrustação, por outro lado, pode afetar uma ampla gama de espécies que podem tolerar alguma epibiose. Vários outros, por outro lado, mantêm agressivamente os epibiontes fora de sua superfície corporal (anti-incrustante). As defesas anti-incrustantes são construídas em plantas marinhas como algas marinhas e ervas marinhas. Elas têm uma estrutura de superfície distinta com picos semelhantes a agulhas bem compactadas e coberturas anti-incrustantes, o que pode dificultar a capacidade de fixação das bactérias. A resistência química anti-incrustante é provavelmente uma reação biológica às desvantagens ecológicas da epibiose, especialmente para organismos capazes de realizar fotossíntese. O objetivo deste estudo foi verificar a eficácia dos compostos naturais derivados de algas marinhas do litoral na prevenção da incrustação. O mexilhão-marrom, importante organismo incrustante, foi avaliado em bioensaios de laboratório contra extratos orgânicos brutos de 51 populações, incluindo duas espécies de macroalgas. A atividade anti-incrustante exibiu um padrão filogenético distinto, com macroalgas vermelhas tendo a maior participação de espécies ativas, posteriormente macroalgas marrons. A ação anti-incrustante em algas verdes nunca foi significativa. Sete espécies apresentaram algum nível de defesa anti-incrustante induzida. Nossas descobertas parecem corroborar descobertas anteriores sobre a síntese de metabólitos secundários em algas marinhas, indicando que, na busca por novos anti-incrustantes, os pesquisadores devem concentrar seus esforços em macroalgas vermelhas tropicais.

Chemical defense in developmental stages and adult of the sea star Echinaster (Othilia) brasiliensis.

To date, evidence regarding the performance of secondary metabolites from larval stages of sea stars as an anti-predation defense relates only to a few species/specimens from a few geographic ranges. Unfortunately, this hinders a comprehensive global understanding of this inter-specific predator-prey interaction. Here, we present laboratory experimental evidence of chemical defense action in the early developmental stages and adults of the sea star Echinaster (Othilia) brasiliensis from Brazil against sympatric and allopatric invertebrate consumers. Blastulae, early and late brachiolarias of E. (O.) brasiliensis were not consumed by the sympatric and allopatric crabs Mithraculus forceps. Blastulae were also avoided by the sympatric and allopatric individuals of the anemone Anemonia sargassensis, but not the larval stages. Extracts from embryos (blastula) and brachiolarias of E. (O.) brasiliensis from one sampled population (João Fernandes beach) significantly inhibited the consumption by sympatric M. forceps, but not by allopatric crabs and A. sargassensi anemone. In this same site, extracts from adults E. (O.) brasiliensis significantly inhibited the consumption by sympatric and allopatric specimens of the crab in a range of concentrations. Whereas equivalent extract concentrations of E. (O.) brasiliensis from other population (Itaipu beach)inhibited the predation by allopatric M. forceps, while sympatric individuals of this crab avoided the only the higher level tested. Then, early stages and adult specimens of E. (O.) brasiliensis can be chemically defended against consumers, but this action is quite variable, depending on the type (anemone or crab) and the origin of the consumer (sympatric or allopatric).

A Review of "Polychaeta" Chemicals and their Possible Ecological Role.

Despite the many publications concerning the isolation of substances and the many reviews of marine natural products, some groups of organisms remain poorly studied, including "Polychaeta". In response, this review covers articles published through December 2016 that address marine natural products produced from polychaetes, with a focus on antipredatory strategies, competitors, fouling, and pathogens. A total of 121 compounds were isolated from 1934 to 2016, which includes halogenated aromatics, proteins, amino acids and Lumazine derivatives most notably-with a defensive function were found in the literature, most frequently in the families Sabellidae, Terebellidae, Glyceridae, and Nereididae. The period of highest discovery of natural products in defensive actions for the group was the 2000s. Polychaetes were addressed in 26 revisions of the total 51 articles analyzed and are less reported than other marine invertebrates such as sponges, cnidarians, mollusks, and tunicates. In sum, the present review provides a basis for future research on the marine chemical ecology of polychaetes.

Structuring effects of chemicals from the sea fan Phyllogorgia dilatata on benthic communities.

Despite advances in understanding the ecological functions of secondary metabolites from marine organisms, there has been little focus on the influence of chemically-defended species at the community level. Several compounds have been isolated from the gorgonian octocoral Phyllogorgia dilatata, a conspicuous species that forms dense canopies on rocky reefs of northern Rio de Janeiro State, Brazil. Manipulative experiments were performed to study: (1) the effects of live colonies of P. dilatata (physical presence and chemistry) on recruitment of sympatric benthic organisms; (2) the allelopathic effects of its chemicals on competitors; and (3) chemotactic responses of the non-indigenous brittle star, Ophiothela mirabilis. Early establishment of benthic species was influenced on substrates around live P. dilatata colonies and some effects could be attributed to the gorgonian's secondary metabolites.In addition, the gorgonian chemicals also exerted an allelopathic effect on the sympatric zoanthid Palythoa caribaeorum, and positive chemotaxis upon O. mirabilis. These results indicate multiple ecological roles of a chemically-defended gorgonian on settlement, sympatric competitors, and non-indigenous species.

Estudio de prefrrmulación para el desarrollo deun gel a base de polímeros con capacidad mucoadhesiva para ensayos de alelopatía en invertebrados mriinos. / Preformulation study for the development of a polymer-based gel with mucoadhesive propierties for its use in allelopathy assays in marine invertebrates

La investigación se desarrolló con el fin de implementar una metodología que permitiera la realización de ensayos de interacciones alelopáticas entre corales y esponjas, minimizando la interacción física provocada por el uso de dispositivos que producen roce y efecto abrasivo sobre los pólipos del coral. Se llevó a cabo un estudio de preformulación utilizando polímeros con características mucoadhesivas sobre mucus que recubre los pólipos de coral, con el fin de obtener un gel, incorporando en las formulaciones un extracto de la esponja Cliona delitrix. Se caracterizaron propiedades como extensibilidad y adherencia, así como la capacidad bioadhesiva de las formulaciones propuestas, considerando su comportamiento reológico. Estas mostraron una buena estabilidad física frente a las condiciones del medio marino tanto in vitro como in situ. De igual manera, se diseñó un dispositivo que facilitó la aplicación del gel sobre la superficie de los corales por parte de los buzos en el arrecife coralino. Finalmente se estudió el comportamiento de liberación al medio acuoso simulado del gel con el extracto de la esponja objeto de estudio.

This study was carried out with the purpose of implementing a methodology to assess allelopathic interactions assays between corals and reef sponges reducing the physical interaction caused by the use of devices that involve abrasion and harm over the coral polyps. Was carried out a preformulation study using polymers with mucoadhesive on the mucus that cover the coral polyps, with the purpose of develop a gel, incorporating an extract from Cliona Delitrix into the formulations. Obtained formulations were characterized by properties such as extensibility, adherence and mucoadhesive capacity. These formulations showed great physical stability under prevalent marine conditions both in vitro and in situ. In the same way was designed a device that let the smearing of the gel over the coral surfaces carried out for the divers in the coral reefs. Finally, was studied the releasing behavior of the gel with the sponge´s extract into the sea water conditions.