Protopalythoa is a zoanthid that, together with thousands of predominantly marine species, such as hydra, jellyfish, and sea anemones, composes the oldest eumetazoan phylum, i.e., the Cnidaria. Some of these species, such as sea wasps and sea anemones, are highly venomous organisms that can produce deadly toxins for preying, for defense or for territorial disputes. Despite the fact that hundreds of organic and polypeptide toxins have been characterized from sea anemones and jellyfish, practically nothing is known about the toxin repertoire in zoanthids. Here, based on a transcriptome analysis of the zoanthid Protopalythoa variabilis, numerous predicted polypeptides with canonical venom protein features are identified. These polypeptides comprise putative proteins from different toxin families: neurotoxic peptides, hemostatic and hemorrhagic toxins, membrane-active (pore-forming) proteins, protease inhibitors, mixed-function venom enzymes, and venom auxiliary proteins. The synthesis and functional analysis of two of these predicted toxin products, one related to the ShK/Aurelin family and the other to a recently discovered anthozoan toxin, displayed potent in vivo neurotoxicity that impaired swimming in larval zebrafish. Altogether, the complex array of venom-related transcripts that are identified in P. variabilis, some of which are first reported in Cnidaria, provides novel insight into the toxin distribution among species and might contribute to the understanding of composition and evolution of venom polypeptides in toxiferous animals.

Long non-coding RNAs (lncRNAs) have been shown to play regulatory roles in a diverse range of biological processes and are associated with the outcomes of various diseases. The majority of studies about lncRNAs focus on model organisms, with lessened investigation in non-model organisms to date. Herein, we have undertaken an investigation on lncRNA in two zoanthids (cnidarian): Protolpalythoa varibilis and Palythoa caribaeorum. A total of 11,206 and 13,240 lncRNAs were detected in P. variabilis and P. caribaeorum transcriptome, respectively. Comparison using NONCODE database indicated that the majority of these lncRNAs is taxonomically species-restricted with no identifiable orthologs. Even so, we found cases in which short regions of P. caribaeorum’s lncRNAs were similar to vertebrate species’ lncRNAs, and could be associated with lncRNA conserved regulatory functions. Consequently, some high-confidence lncRNA-mRNA interactions were predicted based on such conserved regions, therefore revealing possible involvement of lncRNAs in posttranscriptional processing and regulation in anthozoans. Moreover, investigation of differentially expressed lncRNAs, in healthy colonies and colonial individuals undergoing natural bleaching, indicated that some up-regulated lncRNAs in P. caribaeorum could posttranscriptionally regulate the mRNAs encoding proteins of Ras-mediated signal transduction pathway and components of innate immune-system, which could contribute to the molecular response of coral bleaching.

No abstract

In Brazilian reefs, zoanthids, especially Palythoa caribaeorum are fundamental for structuring the local benthic community. The objective of this study was to determine the growth rate of P. caribaeorum, and to assess the influence of the site (different beaches), season (dry and wet), location (intertidal or infralittoral zones), and human pressure associated with tourism. For one year we monitored the cover of P. caribaeorum in transects and focused on 20 colonies. We cut off a square (100 cm 2 ) from the central part of the colony and monitored the bare area for four months in each season. The average growth rates varied from 0.015 and 0.021 cm.day -1 . The rate was homogeneous in all localities, and there was no influence from colony site, location, or touristic visitation, showing that the growth velocity may be an intrinsic characteristic of the species, with a strong genetic component. The growth rate of P. caribaeorum differed among months, and peaked in the first month after injury. The average cover varied from 6.2 to 22.9% and was lower on the reef visited by tourists. The present study corroborates the hypothesis that P. caribaeorum is important for coastal reef dynamics due to its fast and continuous growth.

No abstract

No abstract

Octocorals are common components of sublittoral benthic communities in temperate, tropical and polar areas. However, their natural diets and feeding rates are poorly known. The aim of this study was to determine qualitatively–quantitatively the diet of the octocoral Carijoa riisei (snowflake coral) and analyse the distribution and diet composition throughout a whole year at two different depths of the same environment. Hence, 30 colonies were haphazardly sampled for gastric content analysis from 2 and 6 m deep (surface and bottom) at Porto de Galinhas beach, Pernambuco, Brazil, in January, June and October 2006, and March 2007. Relative and absolute abundance, richness and occurrence frequency per gastric cavity were assessed. Shannon–Wiener index (H′) and evenness were also calculated. Items were classified according to the occurrence frequency. The biovolume of preys was estimated from meristic data, and from the biovolume were then estimated wet weight, dry weight and organic carbon. Weighed biovolume (WBV), which relates biomass and abundance, was assessed to estimate the real contribution of preys to octocoral diet. Results attested the presence of 102 phytoplankton and 25 zooplankton taxa. Mean prey size was 112.7 µm. Diatoms showed the greater richness with 88 morphotypes. Only cyanophytes and diatoms, from phytoplankton, were very common (>70%). As a whole, phytoplankton was also the most abundant group (83%), followed by crustacean fragments (5%). Thus, although having low biovolume (<0.09 mm3×10−3), the phytoplankton showed the highest WBV (44.5%). Feeding items richness was homogeneous throughout the study year and in both depths, while abundance showed significant seasonal and bathymetric fluctuation. The t-test (Hutchinson) found significant differences for prey item diversity related to depth and season. From the analysis, it is possible to conclude that the C. riisei population of the Brazilian north-eastern coast is polyphagous, but shows preference for phytoplanktonic elements and small prey. Therefore, the species behaves as a passive suspensivorous feeder with equitable biomass contribution from phytoplankton and zooplankton.

This is the first record of the starlet sea anemone, Nematostella vectensis Stephenson, 1935, in Southern Hemisphere waters. Specimens of N. vectensis were collected in the surroundings of the Port of Recife, Pernambuco, Brazil. The species is native to the Atlantic coast of the United States of America; populations along the Pacific coast of the USA and the coasts of England are the result of anthropogenic introduction, probably associated with ships and boats used in oyster commerce (Sheader et al. 1997; Pearson et al. 2002; Reitzel et al. 2008). The present study extends the latitudinal distribution of this species, and we discuss the presence on the Brazilian coast of this exotic species.