Avaliação do potencial antiparasitário de um Alcaloide Indólico isolado do Coral Marinho Tubastraea tagusensis / Evaluation of the Antiparasitic Potential of an Indole Alkaloid isolated from the Marine Coral Tubastraea tagusensis

Diante da falta de uma terapia eficaz e segura para o tratamento da doença de Chagas (DC) e da leishmaniose visceral, a busca por novos fármacos continua imprescindível. O ambiente marinho é uma rica fonte de produtos naturais bioativos, com aplicações contra parasitas, bactérias e outros patógenos que possam afetar humanos e animais. Entre as diversas classes de produtos naturais, os alcaloides têm um importante papel em aplicações terapêuticas. Neste trabalho, colônias de coral Tubastraea tagusensis foram coletadas, e a extração de seus metabolitos secundários foi realizada utilizando o solvente orgânico. Após fracionamento cromatográfico por diferentes técnicas, um alcaloide indolico foi isolado e elucidado estruturalmente por meio de técnicas espectrométricas e espectroscópicas. O alcaloide 6-bromo-2'-de-N-metillaplisinopsina (MR01), demonstrou atividade contra tripomastigotas e amastigota intracelulares de Trypanosoma cruzi, com valores de Concentração Efetiva 50% de 62 µM e 5 µM, respectivamente...(AU)

Considering the lack of effective and safe therapy for the treatment of Chagas disease (CD) and visceral leishmaniasis, the search for new chemotherapies remains indispensable. The marine environment is a well-known source of bioactive products, with applications against parasites, bacteria and other human / animal pathogenic microorganisms. Among different classes of natural products, alkaloids have a rich history of therapeutic applications. In this work, colonies of the coral Tubastraea tagusensis were collected and their secondary metabolites were extracted with ethyl acetate. Using different chromatographic techniques, an indole alkaloid was isolated and elucidated through spectroscopic and spectrometric techniques, resulting in the 6-bromo-2'-de-Nmethylaplisinopsin (MR01). The compound MR01 demonstrated activity against Trypanosoma cruzi, against both trypomastigote and amastigote forms, resulting in 50% Effective Concentration (EC50) values of 62 µM and 5 µM, respectively. The studies with Leishmania infantum amastigotes showed lack of activity. No cytotoxicity was observed for NCTC cells, to the maximal concentration of 200 µM. The mechanism of action was also explored. After incubation with the trypomastigotes, no alteration was observed in the permeability of the plasma membrane. The compound reduced the ATP and induced mitochondrial depolarization with no alterations in the reactive oxygen species levels. The intracellular calcium levels were reduced after treatment with MR01, including the pH alterations of the acidocalcisomes. Using MALDI-TOF/MS, the protein profile of the parasite was altered to a different manner to that observed for the standard drug benznidazole, suggesting a distinct mechanism of action. In silico studies of the pharmacokinetic / pharmacodynamic properties (PKPD) and physicochemical properties using the SwissADME software, suggested a good drug-like. In conclusion, this study showed for the first time the anti-T. cruzi activity of the alkaloid MR01. In addition, considering the potency and selectiveness, our study can suggest this compound to be explored as a new prototype for CD. (AU)

Genetic connectivity of the metapopulation of the coral Pocillopora verrucosa (Scleractinia: Pocilloporidae) in multi-use marine protected areas of the Gulf of California, and management implications / Conectividad genética de la metapoblación del coral Pocillopora verrucosa (Scleractinia: Pocilloporidae) en áreas protegidas multipropósito del Golfo de California, e implicaciones de manejo

Abstract Introduction: Estimates of contemporary connectivity of the broadcast spawning coral Pocillopora verrucosa between multi-use marine protected areas (MUMPAs) are required to assess MUMPA effectiveness and their ability to enhance resilience against disturbances. Objective: To determine the genetic structure and connectivity patterns between P. verrucosa demes inside the Gulf of California and evaluate the role and effectiveness of established MUMPAS in their protection and resilience. Methods: We assessed P. verrucosa connectivity along its peninsular range (∼350 km), including five locations and three MUMPAs in the Gulf of California using six microsatellite genetic markers. Results: Population structure was significant (F ST = 0.108***) when demes included clonal replicates; however, when these clones were removed from the analysis, the sexual individuals comprised a metapopulation panmixia (F ST = 0.0007 NS). To further understand connectivity patterns, an assignment test was carried out which identified ten recent between-deme migrants with a mean dispersal distance of 116.6 km (± 80.5 SE). No long-distance dispersal was detected. These results highlight the ecological importance of the Bahía de La Paz region, including Archipiélago de Espíritu Santo MUMPA. This region, located at the center of the species peninsular range, exports larva to downstream sink demes such as the Loreto (northwardly) and Cabo Pulmo (southwardly) MUMPAs. Of importance, inter-MUMPA spacing was larger than the mean larval dispersal by ~56 km, suggesting thar the designation of intermediate 'no-take' zones would enhance short-distance connectivity. Conclusion: This study contributes as a baseline for policymakers and authorities to provide robust strategies for coral ecosystem protection and suggest that protection efforts must be increased towards peninsular intermediate reefs to promote metapopulation resilience from natural and anthropogenic factors.

Resumen Introducción: La estimación de la conectividad en corales escleractinios, como P. verrucosa, dentro de una red de áreas marinas protegidas (MPA) preestablecidas es fundamental para garantizar la efectividad en su conservación e incrementar su resiliencia. Objetivo: Determinar la estructura genética y la conectividad entre los demes de P. verrucosa dentro del Golfo de California, y evaluar el papel y efectividad de la red preestablecida de áreas marinas protegidas. Métodos: Se evaluó la conectividad de P. verrucosa en cinco locaciones a lo largo del golfo incluyendo tres MPA usando seis marcadores microsatélites. Resultados: Se demostró que existe estructura poblacional adjudicada a la presencia local y heterogénea de individuos clones (F ST = 0.108***); pero al removerlos del análisis, los individuos de origen sexual conformaron una metapoblación en panmixia (F ST = 0.0007 NS). Así mismo, se identificaron 10 potenciales migrantes en la región con una dispersión promedio de 116.57 km (± 80.47 SE) y sin conexión entre localidades extremas. De relevancia, se identificó la importancia ecológica del área central o Bahía de La Paz y MPA Archipiélago Espíritu Santo, como fuente larvaria de corales a toda la región. Además, se determinó que el espacio inter-MPA fue mayor que la distancia de dispersión promedio larvaria mencionada, por lo que sería de importancia ecológica el establecimiento de MPAs intermedias que favorezcan la conectividad a distancias cortas. Conclusiones: Los resultados encontrados en el estudio son pertinentes y contribuyen como línea base para los tomadores de decisiones y autoridades, proporcionando la conectividad de la región para establecer las estrategias de protección apropiadas, sugiriendo aumentar la conservación de las subpoblaciones centrales, la cuales promueven la resiliencia metapoblacional de P. verrucosa ante factores ambientales y/o antropogénicos.

Antimicrobial activity of bacteria isolated from tissue of the coral Palythoa caribaeorum (Zoantharia: Sphenopidae) from Paraíba, Brazil coastal reefs / Actividad antimicrobiana de bacterias aisladas del tejido del coral Palythoa caribaeorum (Zoantharia: Sphenopidae) de los arrecifes costeros de Paraíba, Brasil

Abstract Introduction: The coral-associated bacteria with antimicrobial activity may be important to promote the health of their host through various interactions, and may be explored as a source of new bioactive compounds. Objective: To analyze the antimicrobial activity of bacteria associated with the zoanthid Palythoa caribaeorum from the coral reefs of Carapibus, Paraiba state, Brazil. Methods: The phylogenetic analysis of the bacteria was conducted based on partial sequences of the 16S rRNA gene using molecular and bioinformatics tools. The antimicrobial activity of the 49 isolates was tested against four bacterial strains and one yeast strain: Bacillus cereus (CCT0198), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa and Candida albicans (ATCC 10231). The antibiosis and antibiogram assays were conducted and the Minimal Inhibitory Concentration (MIC) was determined by the microdilution method. Results: The bacterial isolates belonged to Firmicutes phylum (84 % of the isolates) and the Proteobacteria phylum (16 % of the isolates). Among the 49 isolates five genera were found, with the Bacillus genus being the most abundant (82 % of the isolates), followed by Vibrio (10 %), Pseudomonas (4 %), Staphylococcus (2 %) and Alteromonas (2 %). Antibiosis test revealed that 16 isolates (33 %) showed antimicrobial activity against one or more of five tested reference strains. The highest number of antagonistic bacteria were found in the Bacillus genus (12 isolates), followed by Vibrio (three isolates) and Pseudomonas (one isolate) genera. The B. subtilis NC8 was the only isolate that inhibited all tested strains in the antibiosis assay. However, antibiogram test with post-culture cell-free supernatant of NC8 isolate showed the inhibition of only B. cereus, S. aureus and C. albicans, and the lyophilized and dialyzed material of this isolate inhibited only B. cereus. The lyophilized material showed bacteriostatic activity against B. cereus, with a MIC value of 125 μg/μl, and in the cytotoxicity assay, the hemolysis value was of 4.8 %, indicating its low cytotoxicity. Conclusions: The results show the antimicrobial potential of some bacterial isolates associated with the P. caribaeourum tissue, especially those belonged to Bacillus genus.

Resumen Introducción: La actividad antimicrobiana realizada por las bacterias asociadas con los corales, además de promover la salud de su huésped, representa una fuente para obtener nuevos compuestos bioactivos. Objetivo: Analizar la actividad antimicrobiana de las bacterias asociadas con el zoantario Palythoa caribaeorum de los arrecifes de Carapibus, Paraíba, Brasil. Metodología: El análisis filogenético de la bacterias se realizó con base en secuencias parciales del gen RNAr 16S utilizando herramientas moleculares y de bioinformática. La actividad antimicrobiana de las cepas se probó contra cuatro cepas bacterianas y una cepa de levadura: Bacillus cereus (CCT0198), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa y Candida albicans (ATCC 10231), utilizando ensayos antibiosis y antibiograma, y la concentración inhibitoria mínima (CIM) que se determinó por el método de microdilución. Resultados: Las cepas bacterianas pertenecían a Firmicutes (84 %) y Gammaproteobacteria (16 %). Entre 49 cepas se encontraron cinco géneros de bacterias: Bacillus, Vibrio, Pseudomonas, Staphylococcus y Alteromonas. Un total de 19 cepas exhibieron actividad antimicrobiana, siendo el género Bacillus el responsable del mayor número de bacterias antagonistas, con 12 cepas positivas en el ensayo de antibiosis y cuatro en la prueba de antibiograma. El mayor número de bacterias antagonistas se encontró en Bacillus (12 aislamientos), seguido por Vibrio (tres aislamientos) y Pseudomonas (un aisladmiento). El NC8, clasificado como Bacillus subtilis, inhibió todas las cepas estándar en el ensayo de antibiosis y las cepas de B. cereus, S. aureus y C. albicans en la prueba de antibiograma. El material liofilizado del B. subtilis NC8 mostró acción bacteriostática contra B. cereus, con un valor de CIM de 125 μg/μl. En la prueba de citotoxicidad, el grado de hemólisis fue del 4.8 % para el material liofilizado a las concentraciones probadas, lo que indica su baja citotoxicidad. Conclusión: Los resultados muestran el potencial antimicrobiano de algunos aislamientos bacterianos asociados al P. caribaeourum, especialmente los pertenecientes al género Bacillus.

Cnidae sizes in the two morphotypes of the giant Caribbean anemone Condylactis gigantea (Actiniaria: Actiniidae) / Tamaños de cnidae en dos morfotipos de la anémona gigante del Caribe Condylactis gigantea (Actiniaria: Actiniidae)

Abstract The sea anemone Condylactis gigantea is an ecologically important member of the benthic community in coral reefs of the tropical Atlantic, and displays two morphotypes with respect to the color in their tentacular tips: the green tip morphotype and the pink/purple tip morphotype. Although some molecular and ecological differences have been found between these morphotypes, no other morphological distinctions have been reported, and currently both are still considered a single taxonomic species. In the present study, we perform an exploration on the variability in the size of cnidae between these two morphotypes and performed statistical analyses to compare the 10 categories of cnidae from specimens hosted in the Cnidarian Collection of Gulf of Mexico and Mexican Caribbean, of the Universidad Nacional Autónoma de México, which were previously collected in several coral reefs localities of the Yucatán Peninsula. Results reveal no significant variation in cnidae size between the two morphotypes, but significant variations were found within each morphotype. In addition, we update the composition of the cnidom of C. gigantea, and the utility of the size of cnidae to distinguish between morphotypes or closely related species is discussed. Rev. Biol. Trop. 66(3): 1055-1064. Epub 2018 September 01.

Resumen La anémona Condylactis gigantea es un miembro ecológicamente importante de la comunidad bentónica en arrecifes de coral del Atlántico tropical, y exhibe dos morfotipos con respecto al color de las puntas de sus tentáculos: el morfotipo de puntas verdes y el morfotipo de puntas rosadas/púrpuras. Aunque se han encontrado algunas diferencias moleculares y ecológicas entre estos morfotipos, no se han reportado otras distinciones morfológicas, y actualmente ambos siguen siendo considerados una sola especie taxonómica. En el presente estudio, realizamos una exploración sobre la variabilidad en el tamaño de los cnidocistos entre estos dos morfotipos y realizamos un análisis estadístico de 10 categorías de cnidocistos a partir de especímenes albergados en la Colección de cnidarios del Golfo de México y Caribe Mexicano, de la Universidad Nacional Autónoma de México, los cuales fueron previamente recolectados en varias localidades arrecifales de la Península de Yucatán. Los resultados no revelan variación significativa en el tamaño de los cnidocistos entre los dos morfotipos, aunque fueron encontradas variaciones significativas dentro de cada morfotipo. Adicionalmente, actualizamos la composición del cnidoma de C. gigantea, y discutimos sobre la utilidad de la talla de los cnidocistos para distinguir entre morfotipos o entre especies estrechamente relacionadas.

Population dynamics of Siderastrea stellata Verrill, 1868 from Rocas Atoll, RN: implications for predicted climate change impacts at the only South Atlantic atoll

ABSTRACT Coral reefs are one of the most vulnerable ecosystems to ocean warming and acidification, and it is important to determine the role of reef building species in this environment in order to obtain insight into their susceptibility to expected impacts of global changes. Aspects of the life history of a coral population, such as reproduction, growth and size-frequency can contribute to the production of models that are used to estimate impacts and potential recovery of the population, acting as a powerful tool for the conservation and management of those ecosystems. Here, we present the first evidence of Siderastrea stellata planulation, its early growth, population size-frequency distribution and growth rate of adult colonies in Rocas Atoll. Our results, together with the environmental protection policies and the absence of anthropogenic pressures, suggest that S. stellata population may have a good potential in the maintenance and recovery in the atoll. However, our results also indicate an impact on corals' recruitment, probably as a consequence of the positive temperature anomaly that occurred in 2010. Thus, despite the pristine status of Rocas Atoll, the preservation of its coral community seems to be threatened by current global changes, such as more frequent thermal stress events.

Influence of sediments and tungsten traces on the skeletal structure of Pseudodiploria: a reef building scleractinian coral from the Veracruz Reef System National Park, Mexico / Influencia de los sedimentos y trazas de tungsteno en la estructura del esqueleto de Pseudodiploria un coral escleractinio constructor de arrecifes del Parque Nacional Sistema Arrecifal Veracruzano, México

Abstract:Coral reefs are under intense conditions of stress caused by the anthropogenic activities in coastal areas and the increase of human population. Water effluents from urban and industrial areas carry large amounts of sediments and pollutants affecting corals populations, inducing bioerosion, increasing diseases and promoting the development of algae that compete for space with corals. In the Veracruz Reef System National Park (VRSNP) coral reefs are strongly affected by human activities carried out in the area. Gallega and Galleguilla reefs are among the most affected by wastewater discharges from the industrial (petrochemical and metallurgical) and urban areas in their vicinity. To assess the potential impact of this contamination on corals in the VRSNP, a chemical composition and morphology study of 76 Pseudodiploria colonies collected in reefs Gallega, Galleguilla, Isla Verde and Isla de Enmedio, was performed. Fragments of ~10 cm2 were collected and boric acid at 0.5 % was used to remove tissue from the skeleton; once clean, the morphology of each sample was determined with a scanning electron microscope (SEM). Subsequently, to test the chemical composition, an energy dispersion spectroscopy of X-ray chemical microanalysis (EDSX) was performed in the SEM. We found that corals from Gallega and Galleguilla reefs, located closer to human populations, presented high levels of tungsten and the skeleton exhibited multiple perforations. In contrast, corals from the farthest offshore reefs (Isla Verde and Isla de Enmedio) exhibited lower levels of tungsten and fewer perforations in their skeleton. These results demonstrated that anthropogenic activities in the NPVRS are affecting corals skeleton, highly damaging and promoting their bioerosion. The presence of traces of tungsten in the skeleton of corals is an evidence of the damage that waste discharges are causing to coral reefs. Discharges of large amounts of contaminants promoted the growth of harmful species that grow and develop into the corals skeleton, causing its bioerosion, and making them susceptible to disease and physical damage. This study is the first evidence of the effects of contamination on these species; therefore, further studies are necessary to determine the impact of pollution on their biology and survival. Rev. Biol. Trop. 64 (3): 1077-1089. Epub 2016 September 01.

ResumenLos arrecifes de coral se encuentran bajo condiciones intensas de estrés causado por las actividades antropogénicas y el incremento de las poblaciones humanas en las zonas costeras. Las descargas de aguas de origen urbano e industrial transportan sedimentos y contaminantes que afectan a las poblaciones de corales, induciendo la bioerosion, el aumento de enfermedades en los corales y promueven el desarrollo de algas que compiten por espacio con los corales. En el Parque Nacional Sistema Arrecifal Veracruzano (NPVRS) los arrecifes de coral son afectados fuertemente por las actividades humanas que se llevan a cabo en la zona. Los arrecifes Gallega y Galleguilla son de los más afectados por las descargas de aguas residuales provenientes de la industria (petroquímica y metalúrgica) y de áreas urbanas que desembocan sus aguas en las proximidades de los arrecifes. Para evaluar el posible impacto de las descargas de aguas en los corales del NPVRS, se realizó un estudio de la composición química y morfología de 76 colonias de Pseudodiploria en los arrecifes Gallega, Galleguilla, Isla Verde e Isla de Enmedio. Se recolectaron fragmentos de ~10 cm2, el tejido del esqueleto fue removido utilizando ácido bórico al 0.5 %. Una vez limpia la muestra, la morfología fue analizada con un microscopio electrónico de barrido (SEM), posteriormente, para analizar la composición química de las muestras, realizamos una espectroscopia de dispersión de energía o micro-análisis químico de rayos X (EDSX) en el SEM. Encontramos que los corales de los arrecifes Gallega y Galleguilla que se encuentran ubicados cerca de poblaciones humanas, presentan altos niveles de tungsteno y el esqueleto exhibe múltiples agujeros. En contraste, los corales de los arrecifes más lejanos (Isla Verde e Isla de En medio) mostraron niveles más bajos de tungsteno y un menor número de agujeros en su esqueleto. Nuestros resultados demuestran que las actividades antropogénicas en el NPVRS, están afectando el esqueleto de los corales y promueven la bioerosión. Las descargas de grandes cantidades de contaminantes hacia las zonas costeras, promueven el crecimiento de especies dañinas que crecen y se desarrollan dentro del esqueleto de los corales, causando bioerosión del esqueleto, haciéndolos susceptibles a enfermedades y daños físicos. Debido a que este estudio es la primera evidencia de los efectos de la contaminación sobre esta especie de corales, son necesarios más estudios para determinar el impacto de la contaminación sobre su biología y la supervivencia de los corales.

Coral communities condition in varying wave exposure: the gulf of Cazones, Cuba / Condición de comunidades coralinas con diferente exposición al oleaje: El Golfo de Cazones, Cuba

Abstract Wave exposure can influence community structure and distribution of shallow coral reefs, by affecting organisms both directly and indirectly. To assess the current stony coral community condition under different degrees of wave exposure at a marine protected area of the Gulf of Cazones (SW Cuba), two expeditions were carried out in May 2010 and June 2012. Four sampling sites were sampled at reef crests (1.5 m deep), and twelve at fore-reefs, at 10, 15 and 20 m deep in four geographic locations. Live coral cover, species richness and composition, colony density, and maximum diameter were assessed using the AGRRA 2001 methodology. Multivariate and non-parametric statistics were applied to compare sites. The coral community structure within reef crests was not homogenous. The observed variability of indicators apparently was determined by great coral mortality events resulting from natural disturbances that occurred in the past (hurricanes, bleaching and diseases). Forereef coral communities displayed better condition and lower coral mortality than reef crests. Species richness and coral composition varied, while multivariate and statistical methods did not reveal site grouping with regard to wave exposure. The remaining biological condition indicators were similar among sites, except in the most exposed one, where coral cover and coral size were slightly lower. Wave exposure in the gulf of Cazones seemed not to have a significant influence on differences in condition and structure of the assessed coral communities. Rev. Biol. Trop. 64 (1): 78-93. Epub 2016 March 01.

ResumenEl oleaje es una perturbación natural que puede inferir en la estructura y condición de los arrecifes de coral someros, afectando los organismos directa e indirectamente. Para evaluar la condición de comunidades de corales con diferente exposición al oleaje, se realizaron dos expediciones al Área Marina Protegida del Golfo de Cazones durante mayo 2010 y junio 2012. Se escogieron cuatro arrecifes (localidades) ubicados en posiciones diferentes del golfo. Se ubicaron cuatro sitios en la zona de cresta (1.5 m de profundidad) y 12 en la zona de arrecife frontal (en cuatro localidades a 10, 15 y 20 m de profundidad) donde se replicaron transectos lineales (10 m de largo) de muestreo. Se evaluó la cobertura de coral vivo, riqueza y composición por especies, densidad y diámetro máximo de las colonias mediante la metodología AGRRA 2001. Para la comparación entre sitios se aplicaron métodos evaluativos multivariados y análisis estadísticos no paramétricos. La estructura y condición de la comunidad de corales en las crestas fue distinta pero la variabilidad observada parece responder a grandes eventos de mortalidad producto de huracanes, blanqueamientos y enfermedades del pasado. La condición de los arrecifes frontales fue más favorable observándose menor mortalidad coralina. La riqueza y composición por especies fue variable y los métodos estadísticos y multivariados no definieron grupos de sitios con similitud respecto a la exposición al oleaje. Los demás indicadores biológicos de condición fueron parecidos entre sitios, excepto en el más expuesto al oleaje, donde la cobertura y la talla de los corales fueron ligeramente inferiores. En general, la diferente influencia del oleaje dentro del golfo de Cazones, parece no afectar significativamente la estructura y condición de las comunidades coralinas.

Composition and biological activities of the aqueous extracts of three scleractinian corals from the Mexican Caribbean: Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea

Scleractinian corals (stony corals) are the most abundant reef-forming cnidarians found in coral reefs throughout the world. Despite their abundance and ecological importance, information about the diversity of their toxins and their biological activities is very scarce. In this study, the chemical composition and the biological activities of the aqueous extracts of Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea, three scleractinian corals from the Mexican Caribbean, have been assessed for the first time. Methods: Toxicity of the extracts was assessed in crickets; the presence of cytolysins was detected by the hemolysis assay; the vasoconstrictor activity was determined by the isolated rat aortic ring assay; the nociceptive activity was evaluated by the formalin test. The presence of phospholipases A2 (PLA2), serine proteases, and hyaluronidases was determined by enzymatic methods. Low-molecular-weight fractions were obtained by gel filtration chromatography and ultrafiltration. Results: Extracts from the three species were toxic to crickets, induced hemolysis in human and rat erythrocytes, produced vasoconstriction on isolated rat aortic rings, and presented phospholipase A2 and serine-protease activity. Despite the fact that these corals are not considered to be harmless to humans, the extracts generated significant nociceptive responses. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of the low-molecular-weight fractions revealed the presence of peptides within a mass range of 3000 to 6000 Da. These fractions were toxic to crickets and two of them induced a transitory vasoconstrictor effect on isolated rat aortic rings. Conclusion: This study suggests that scleractinian corals produce low-molecular-weight peptides that are lethal to crickets and induce vasoconstriction.

Alcanivorax dieselolei, an alkane-degrading bacterium associated with the mucus of the zoanthid Palythoa caribaeorum (Cnidaria, Anthozoa) / Alcanivorax dieselolei, uma bactéria degradadora de alcanos associada ao muco do zoantídeo Palythoa caribaeorum (Cnidaria, Anthozoa)

Analyses of 16S rDNA genes were used to identify the microbiota isolated from the mucus of the zoanthid Palythoa caribaeorum at Porto de Galinhas on the coast of Pernambuco State, Brazil. This study is important as the first report of this association, because of the potential biotechnological applications of the bacterium Alcanivorax dieselolei, and as evidence for the presence of a hydrocarbon degrading bacterium in a reef ecosystem such as Porto de Galinhas.

Análises dos genes 16S rDNA foram empregadas para identificar a microbiota isolada do muco do zoantídeo Palythoa caribaeorum de Porto de Galinhas, litoral do estado de Pernambuco, Brasil. Este estudo é importante pelo ineditismo dessa associação, pelas relevantes aplicações biotecnológicas da bactéria Alcanivorax dieselolei e pela indicação da presença de uma bactéria degradadora de hidrocarbonetos em um ecossistema recifal como o de Porto de Galinhas.

Alcanivorax dieselolei, an alkane-degrading bacterium associated with the mucus of the zoanthid Palythoa caribaeorum (Cnidaria, Anthozoa) / Alcanivorax dieselolei, uma bactéria degradadora de alcanos associada ao muco do zoantídeo Palythoa caribaeorum (Cnidaria, Anthozoa)

Analyses of 16S rDNA genes were used to identify the microbiota isolated from the mucus of the zoanthid Palythoa caribaeorum at Porto de Galinhas on the coast of Pernambuco State, Brazil. This study is important as the first report of this association, because of the potential biotechnological applications of the bacterium Alcanivorax dieselolei, and as evidence for the presence of a hydrocarbon degrading bacterium in a reef ecosystem such as Porto de Galinhas.

Análises dos genes 16S rDNA foram empregadas para identificar a microbiota isolada do muco do zoantídeo Palythoa caribaeorum de Porto de Galinhas, litoral do estado de Pernambuco, Brasil. Este estudo é importante pelo ineditismo dessa associação, pelas relevantes aplicações biotecnológicas da bactéria Alcanivorax dieselolei e pela indicação da presença de uma bactéria degradadora de hidrocarbonetos em um ecossistema recifal como o de Porto de Galinhas.

Cytolytic and systemic toxic effects induced by the aqueous extract of the fire coral Millepora alcicornis collected in the Mexican Caribbean and detection of two types of cytolisins

Background Millepora alcicornis is a branching hydrocoral common throughout the Caribbean Sea. Like other members of this genus, this species is capable of inducing skin eruptions and blisters with severe pain after contact. In the present study, we investigated the toxicity of theM. alcicornis aqueous extract on several animal models. Considering that some cnidarian hemolysins have been associated to local tissue damage, since they also induce lysis of other cell types, we also made a partial characterization of the hemolytic activity of M. alcicornis aqueous extract. This information is important for understanding the defense mechanisms of the fire corals.Methods The effects of pH, temperature, and some divalent cations on the hemolytic activity of the extract were assayed, followed by a zymogram analysis to detect the cytolysins and determine their approximate molecular weight. The toxicity of the aqueous extract was assayed in mice, by intravenous administration, and histopathological changes on several tissues were analyzed by light microscopy. The toxicity of the extract was also tested inArtemia salina nauplii, and the damages caused on the crustaceans were analyzed by transmission and scanning electron microscopy.Results The hemolytic activity of the hydrocoral extract was enhanced in the presence of Ca 2+ (2 mM), Mg 2+ (6 mM), and Ba2+ (0.1 mM); however, it was reduced in the presence of Cu2+(0.1 mM), Zn 2+ (6 mM), and EDTA (0.34 mM). Differences in the pH did not affect the hemolytic activity, but it was temperature-sensitive, since preincubation at 50 °C sharply reduced hemolysis. The zymogram showed the presence of two types of hemolysins: ~ 2830 kDa proteins with phospholipase A 2 activity and ~ 200 kDa proteins that do not elicit enzymatic activity. The aqueous extract of this cnidarian was lethal to mice (LD 50 = 17 g protein/g), and induced kidney, liver, and lung damages. Under denaturing conditions, the aqueous extract completely lost its toxic and hemolytic activities.Conclusions The results showed that the M. alcicornis aqueous extract contains two types of thermolabile hemolysins: proteins of approximately 2830 kDa with PLA 2 activity, while the others are larger proteins of approximately 200 kDa, which do not possess PLA 2activity. Those thermolabile cytolysins, which are stable to pH changes and whose activity is calcium dependent, are capable of inducing damage in lung, kidney and liver tissues, resulting in a slow death of mice. M. alcicorniscytolysins also provoke tissue dissociation inArtemia salina nauplii that might be attributed to pore forming mechanisms.

Sulfate reducing bacteria as secondary and necessary pathogens in black band disease of corals / Bacterias reductoras de sulfato como patógenos secundarios y necesarios en la enfermedad de la banda negra de coral

Black band disease (BBD) is a complex, polymicrobial disease that consists of cyanobacteria, sulfide-oxidizing and sulfate-reducing bacteria (SRB), and heterotrophic bacteria. The cyanobacterium Roseofilum reptotaenium has been implicated as the primary pathogen of BBD, but other consortium members may be secondary pathogens that are necessary to the development of the disease. It is known that populations of the sulfate-reducing bacterium Desulfovibrio are present in BBD and that these populations generate sulfide within the band as a byproduct of dissimilatory sulfate reduction. It is also known that exposure of healthy corals to sulfide leads to cell lysis and coral tissue death. Previous work showed that when freshly collected BBD, which easily infects healthy corals, is exposed to sodium molybdate, a specific inhibitor of sulfate reduction, infection does not occur. In this study we examined the effect of sodium molybdate on infection of corals by a unialgal culture of R. reptotaenium. Coral fragments of Montastraea cavernosa and Siderastrea siderea were transferred into two experimental aquaria, one a control with only artificial seawater (ASW) and the second containing ASW and 2mM sodium molybdate. Small mats of cultured R. reptotaenium were inoculated onto the surface of experimental coral fragments. Both M. cavernosa (n = 6) and S. siderea (n=4) became infected and developed BBD-like infections in the control tank, while there were temporary attachments to, but no successful infection of M. cavernosa (n=3) or S. siderea (n=2) in the experimental tank containing sodium molybdate. The results of this study reveal that a secondary pathogen is essential to the infection process and development of BBD in scleractinian corals. Specifically, SRB such as Desulfovibrio are required for the development of BBD on the coral host. This is the first step in understanding the roles of secondary pathogens in a complex, polymicrobial coral disease.

La enfermedad de la Banda Negra (BBD) es una enfermedad polimicrobiana compleja, que consiste en las cianobacterias, sulfuro oxidante y bacterias reductoras de sulfato (SRB) y bacterias heterotróficas. La cianobacteria Roseofilum reptotaenium se considera como el principal patógeno de BBD, pero otros miembros del consorcio pueden ser patógenos secundarios que son necesarios para el desarrollo de la enfermedad. Se conoce que las poblaciones de la bacteria reductora de sulfato Desulfovibrio están presentes en BBD y que estas poblaciones generan sulfuro dentro de la banda como un subproducto de la reducción del sulfato. También se conoce que la exposición de los corales sanos a sulfuro conduce a la lisis celular y la muerte del tejido de coral. Trabajos previos muestran que cuando recién colectado el tejido con BBD, que infecta fácilmente corales sanos, se expone al molibdato de sodio, un inhibidor específico de la reducción del sulfato, la infección no se produce. En este estudio analizamos el efecto del molibdato de sodio sobre la infección de los corales en un cultivo unialgal de R. reptotaenium. Fragmentos de coral de Montastraea cavernosa y Siderastrea siderea se transfirieron a dos acuarios experimentales, uno control con solo agua de mar artificial (ASW) y el segundo que contenía ASW y molibdato de sodio 2mM. Pequeñas esteras de cultivo R. reptotaenium se inocularon en la superficie de fragmentos experimentales de coral. Tanto M. cavernosa (n=6) y S. siderea (n=4) se infectaron y desarrollaron infecciones BBD- como en el tanque de control, mientras que había adjuntos temporales, sin infección exitosa en M. cavernosa (n=3) o S. siderea (n=2) en el tanque experimental con molibdato de sodio. Los resultados de este estudio revelan que un patógeno secundario es esencial para el proceso de infección y el desarrollo de BBD en corales escleractíneos. Específicamente, SRB como Desulfovibrio son necesarios para el desarrollo de BBD en el coral hospedero. Este es el primer paso en la comprensión de las funciones de los patógenos secundarios en una enfermedad polimicrobiana compleja de coral.

Status of the coral reefs in Foul and Folly Bays, Morant Wetlands, south-eastern Jamaica, with emphasis on corals and macroalgae / Estado de los arrecifes de coral en Foul and Folly Bays, Morant Wetlands, sureste de Jamaica, con énfasis en corales y macroalgas

Foul and Folly Bays are located within the Morant Wetlands near the eastern tip of Jamaica. They have never been investigated but were believed to be important for larval productivity because of the extent of benthic habitats, absence of major coastal developments and remote location. The study was aimed at providing baseline data on the spatial distribution and status of corals and associated benthos. We investigated coral reefs and associated areas with phototransects at eight stations analysed with the Coral Point Count software. Most areas were dominated by algae, evidence of a phase shift from coral to algal reefs. Coral cover varied significantly across the bays (ANOVA, p= 0.0342) with a maximum of 27.03% at the deepest station and a mean of 5.6% at all other stations combined. Mean cover of macroalgae was 39% and varied significantly across stations (α= 0.05, F= 7.472, p= 0.005). The deepest station also had the highest percentage of calcareous algae and live coral while dead coral with algae (DCA) was a significant variable across all other stations (ANOVA, p<0.001). Gorgonians (ANOVA, p<0.001), sponges and urchins were also assessed. Diadema antillarum was not observed at any station. Overall the status of the reefs was poor, probably due to overfishing, absence of urchins and the resultant algal proliferation.

Las bahías Foul y Folly se encuentran dentro de los Humedales Morant cerca de la punta oriental de la isla de Jamaica. Estos dos bahías nunca han sido investigadas pero se cree que son áreas importantes para la productividad larvaria debido a la extensión de los hábitats bentónicos, ausencia de desarrollos importantes a lo largo de la costa y la ubicación remota de la zona. El estudio tuvo como objetivo proporcionar datos de referencia sobre la distribución espacial y el estado de los corales y del bentos asociado. Investigamos los arrecifes coralinos y áreas asociadas utilizando fototransectos en ocho estaciones analizadas con el programa Coral Point Count. La mayoría de las áreas tuvieron predominio algal, mostrando evidencia del desplazamiento de fase de coral a algas. La cobertura de coral varió significativamente a través de las bahías (ANOVA , p= 0.0342), con un máximo de 27.03% en la estación estación más profunda y una media de 5.6% en todas las demás estaciones combinadas. La media de porcentaje de cobertura de macroalgas fue de 39% y varió significativamente entre las estaciones (α= 0.05, F= 7.472, p= 0.005). La estación mas profunda presentaba el mayor porcentaje de algas calcáreas y coral vivo, mientras que el coral muerto con algas (DCA) fue una variable significativa en todas las demás estaciones (ANOVA , p<0.001). También se evaluaron las gorgonias (ANOVA , p<0.001), esponjas y erizos de mar. No se observó Diadema antillarum en todas las estaciones dentro de los transectos. En general, el estado de los arrecifes era pobre, probablemente debido a la pesca excesiva, la ausencia de erizos y la proliferación de algas resultante.

Octocoral densities and mortalities in Gorgona Island, Colombia, Tropical Eastern Pacific / Densidades y mortalidades de octocorales en Isla Gorgona, Colombia, Pacífico Oriental Tropical

Owing to the decrease of reef organisms in general, it has become essential to study populations that are prone to marine diseases, with the purpose of developing accurate survivorship predictions and in turn alarm on triggers and drivers of disease outbreaks. In this study, we quantified the octocorals of Gorgona island, Tropical Eastern Pacific (Colombia), during 2007 and 2009 documenting a mass mortality occurred during 2008. We recorded 16 octocoral species with densities that ranged between 2 and 30 colonies m-2. Most abundant octocorals were Leptogorgia alba and Pacifigorgia spp. (Gorgoniidae: Octocorallia). During 2009 we noticed a mass mortality involving Pacifigorgia irene, P. adamsi, P. rubicunda and P. eximia, with a reduction of 70% of the colonies between 12 and 20 m in water depth. Around 5% of seafans during 2007 had an epizootic disease similar to aspergillosis, which seems the cause of the mass octocoral mortality. This disease outbreak observed in Gorgona island, and other nearby areas of the Colombian Pacific during 2007-2010, corresponded to extended periods of anomalous elevated seawater surface temperatures and thermal anomalies during the upwelling season of 2008. Constant monitoring of seawater temperatures and octocoral populations are urgently needed in this area to understand the nature of this new disease outbreak. Rev. Biol. Trop. 62 (Suppl. 1): 209-219. Epub 2014 February 01.

Debido a la disminución de los organismos de los arrecifes en general, es fundamental conocer las poblaciones de organismos propensos a enfermedades marinas, con el propósito de desarrollar predicciones precisas de supervivencia y a su vez dar la alarma sobre los motivos y las causas de los brotes de las enfermedades. En este estudio, hemos cuantificado los octocorales de la Isla Gorgona, Pacífico Oriental Tropical (Colombia), durante 2007 y 2009, y documentamos una mortalidad masiva que se produjo durante el año 2008. Se registraron 16 especies de octocorales con densidades que oscilan entre 2 y 30 colonias m-2. Los octocorales más abundantes fueron Leptogorgia alba y Pacifigorgia spp. (Gorgoniidae: Octocorallia). Durante el año 2009 nos dimos cuenta de una mortalidad masiva que afectaba a Pacifigorgia irene, P. adamsi, P. rubicunda y P. eximia, con una reducción del 70% de las colonias entre 12 y 20 m de profundidad. Alrededor del 5% de los abanicos de mar durante el año 2007 tenían una epizootia similar a la aspergilosis, que parece ser la causa de la mortalidad masiva de octocorales. Este brote de la enfermedad observada en la Isla Gorgona, y otras zonas cercanas del Pacífico colombiano durante el período 2007-2010, corresponden a períodos prolongados de altas temperaturas superficiales del mar y de anomalías térmicas durante la temporada de surgencia durante 2008. Se necesita con urgencia un monitoreo constante de las temperaturas marinas y de las poblaciones de octocorales en esta área para comprender la naturaleza de este nuevo brote de enfermedad marina.

The invasive snowflake coral (Carijoa riisei) in the Tropical Eastern Pacific, Colombia / El coral copo de nieve invasivo (Carijoa riisei) en el Pacífico Oriental Tropical, Colombia

Carijoa riisei (Octocorallia: Cnidaria), a western Atlantic species, has been reported in the Pacific as an invasive species for nearly forty years. C. riisei has been recently observed overgrowing native octocorals at several rocky-coral littorals in the Colombian Tropical Eastern Pacific-(TEP). C. riisei has inhabited these reefs for at least 15 years but the aggressive overgrowth on other octocorals have been noted until recently. Here, we surveyed for the first time the distribution and inter-specific aggression by C. riisei in both coastal and oceanic areas colonized in the Colombian TEP (Malpelo, Gorgona and Cabo Corrientes), including preliminary multiyear surveys during 2007-2013. We observed community-wide octocoral mortalities (including local extinction of some Muricea spp.) and a steady occurrence of competing and overgrowing Pacifigorgia seafans and Leptogorgia seawhips. In Gorgona Island, at two different sites, over 87% (n=77 tagged colonies) of octocorals (Pacifigorgia spp. and Leptogorgia alba) died as a result of C. riisei interaction and/or overgrowth between 2011 and 2013. C. riisei overgrows octocorals with an estimate at linear growth rate of about 1cm m-1. The aggressive overgrowth of this species in TEP deserves more attention and regular monitoring programs. Rev. Biol. Trop. 62 (Suppl. 1): 199-207. Epub 2014 February 01.

Carijoa riisei (Octocorallia: Cnidaria), una especie nativa del Atlántico Occidental. Sin embargo, se ha reportado como especie exótica invasora en el Pacífico desde hace unos cuarenta años y en la costa occidental de Colombia hace 15-20 años. Recientemente C. riisei se ha observado sobrecreciendo octocorales nativos en varios litorales rocosos coralinos en el Pacífico Oriental Tropical-(POT) de Colombia. C. riisei ha habitado estos arrecifes durante al menos 15 años, pero este comportamiento agresivo frente a otros octocorales no se habían notado hasta hace unos pocos años. En este estudio, se evalúa por primera vez, en las zonas costeras y oceánicas, la distribución e incidencia C. riisei en otros octocorales del POT colombiano (Malpelo, Gorgona y Cabo Corrientes), incluyendo información observaciones entre 2007-2013. Hemos observado mortalidad en toda la comunidad de octocorales (incluyendo la extinción local de algunas especies de Muricea) y una constante competencia y cubrimiento de abanicos de mar Pacifigorgia y gorgonáceos Leptogorgia. C. riisei presento una tasa lineal de crecimiento sobre otros octocorales de aproximadamente 1 cm m-1. El comportamiento agresivo de C. riisei en el POT merece más atención y programas regulares de monitoreo.

Acidobacteria appear to dominate the microbiome of two sympatric Caribbean Sponges and one Zoanthid

BACKGROUND: Marine invertebrate-associated microbial communities are interesting examples of complex symbiotic systems and are a potential source of biotechnological products. RESULTS: In this work, pyrosequencing-based assessment from bacterial community structures of sediments, two sponges, and one zoanthid collected in the Mexican Caribbean was performed. The results suggest that the bacterial diversity at the species level is higher in the sediments than in the animal samples. Analysis of bacterial communities' structure showed that about two thirds of the bacterial diversity in all the samples belongs to the phyla Acidobacteria and Proteobacteria. The genus Acidobacteriumappears to dominate the bacterial community in all the samples, reaching almost 80% in the sponge Hyrtios. CONCLUSIONS: Our evidence suggests that the sympatric location of these benthonic species may lead to common bacterial structure features among their bacterial communities. The results may serve as a first insight to formulate hypotheses that lead to more extensive studies of sessile marine organisms' microbiomes from the Mexican Caribbean.

Species composition and bathymetric distribution of gorgonians (Anthozoa: Octocorallia) on the Southern Mexican Pacific coast / Composición de especies y distribución batimétrica de gorgonios (Anthozoa: Octocorallia) en la costa sur del Pacífico mexicano

Gorgonians are important components of coastal ecosystems, as they provide niches, natural compounds with medical applications and are used as bioindicators. Species composition and assemblage structure of gorgonians (Anthozoa: Octocorallia) were studied along a bathymetric profile in the Southern Mexican Pacific coast. Species composition was based on specimens collected within a depth range of 0-70m in 15 sites. The relative abundance of species was determined in six sites at four depths (5, 10, 20 and 25m) using three 10m2 transects at each depth level. Twenty-seven species of gorgonians belonging to six genera and three families were registered. The species composition varied with depth: 11 species were distributed between 0-25m depth, while 17 species were found between 40-70m depth interval. The shallow zone is characterized by a relatively large abundance of gorgonians, dominated by colonies of Leptogorgia cuspidata and L. ena. In contrast, the deepest zone was characterized by relatively low abundance of gorgonians, dominated by L. alba, the only species observed in both depth intervals. The similarity analysis showed differences in the composition and abundance of species by depth and site, suggesting that the main factor in determining the assemblage structure is depth. Results of this study suggest that the highest richness of gorgonian species in the study area may be located at depths of 40-70m, whereas the highest abundances are found between 5 and 10m depth. This study represents a contribution to the poorly known eastern Pacific gorgonian biota.

La composición de especies y estructura de la comunidad de gorgonáceos se determinó a lo largo de un perfil batimétrico en la costa suroeste del Pacífico Mexicano. La composición de especies se realizó a través de una revisión y recolecta de especímenes entre 0 y 70m de profundidad en 15 sitios de muestreo. La caracterización de la estructura de la comunidad se realizó en seis sitios, en los cuales se colocaron tres transectos de 10m² cada uno a 5, 10, 20 y 25m de profundidad. Se encontraron 27 especies de gorgonáceos pertenecientes a seis géneros y tres familias; aunque seis especies requieren ser confirmadas. La mayor riqueza de especies se registró entre 40 y 70m. La estructura de la comunidad entre 5 y 25m de profundidad mostró la existencia de dos zonas con la misma composición de especies pero con diferente abundancia relativa: una somera entre 5 y 10m de profundidad, caracterizada por una mayor abundancia de gorgonáceos y dominado por colonias de Leptogorgia cuspidata y Leptogorgia ena y una zona profunda entre 20 y 25m de profundidad, caracterizada por una baja abundancia de gorgonáceos y dominada por colonias de Leptogorgia alba.

Estructura comunitaria de corales zooxantelados (Anthozoa: Scleractinia) en el arrecife coralino de Carrizales, Pacífico Mexicano / Community structure of zooxanthellate corals (Anthozoa: Scleractinia) in Carrizales coral reef, Pacific coast, Mexico

Coral reefs in the Mexican Pacific and notably those of the continental coastline of Colima state are still poorly studied. Fortunately, recent efforts have been carried out by researchers from different Mexican institutions to fill up these information gaps. The aim of this study was to determine the ecological structure of the rich and undisturbed coral building communities of Carrizales by using the point transect interception method (25m-long). For this, three survey expeditions were conducted between June and October 2005 and September 2006; and for comparison purposes, the reef was subdivided according to its position in the bay, and depth (0 to 5m, and 6 to 10m). Thirteen coral species were observed in the area, with Pocillopora verrucosa as the most abundant, contributing up to 32.8% of total cover, followed by Porites panamensis and Pocillopora capitata with 11% and 7%, respectively. Other species, Pocillopora damicornis, Pavona gigantea, Pocillopora eydouxi and Pocillopora inflata accounted for 1.5% to 2% of coral cover whereas the remaining five species had cover of less than 1%. Seven of the observed species represented new records for Colima state coast- line: Pocillopora eydouxi, P. inflata, P. meandrina, Pavona duerdeni, P. varians, Psammocora stellata and P. contigua. This last species is a relevant record, because it has never been observed before in the Eastern Pacific. Although there was no significant difference (ANOVA, p=0.478) neither in the abundance between the sides of the bay, nor between the depths considered, and the shallow zone observed the higher coral cover. Live coral cover was up to 61%, one of the highest ever reported for the Mexican Pacific, including the Gulf of California. The observed values of diversity (H´=0.44±0.02), uniformity (J´=0.76±0.02), and taxonomic distinctness index (Δ*=45.87±3.16), showed that currently this is the most important coral reef of Colima coastline. Currently, this region does not show any disturbance effects, but the increasing economic development of Manzanillo, as one of the main commercial ports of Mexico, its proximity to the reef, and the burgeoning number of tourists, may have some ecosystem impacts, for which management and conservation plans for Colima coastline are highly recommended.

El conocimiento ecológico de corales arrecifales en el Pacífico mexicano es escaso, por lo que el objetivo de este trabajo fue determinar la estructura de la comunidad de corales hermatípicos en el arrecife de Carrizales, Colima, mediante el uso de transectos y buceo autónomo (junio y octubre 2005, septiembre 2006). De las 13 especies de corales encontradas, Pocillopora verrucosa fue la más abundante y siete representan nuevos registros, sobresaliendo Psammocora contigua, primer registro para el Pacífico Oriental. No hubo diferencias significativas de abundancia entre profundidades, pero la zona somera presenta una mayor cobertura. Este sitio presenta una de las riquezas y cobertura de coral más alta (61%) en el Pacífico Mexicano y valores de diversidad (H´=0.44±0.02), uniformidad (J´=0.76±0.02), y de diferenciación taxonómica (Δ*=45.87±3.16) relativamente altos. Actualmente la región no presenta grandes perturbaciones pero el creciente desarrollo económico de Manzanillo, uno de los principales puertos comerciales del país, además del creciente número de turistas, podrían afectar al arrecife, por lo que se sugiere implementar medidas de protección con el fin de mantener al arrecife más importante del litoral de Colima.

Osmoregulation in tropical zoanthid Protopalythoa variabilis (Cnidaria: Anthozoa) / Osmorregulação no zoantídeo tropical Protopalythoa variabilis (Cnidaria: Anthozoa)

This study evaluated the physiological, morphological and ethological effects of salinity variations on the tropical zoanthid Protopalythoa variabilis. This zoanthid was submitted to different salinity levels to probe the hypothesis of osmoregulation. Specimens collected in beach rocks from Northeastern Brazil were taken alive to the laboratory in their original water. The osmoregulatory ability of P. variabilis can be determined by measuring the hemolymph osmolality under various salinity conditions and comparing with the osmolality of the medium. The zoanthid P. variabilis is a "weak regulator", as it only osmoregulates within a narrow range of external salinity values, and its hemolymph osmolality drops, approximately in parallel with the isosmotic line, when the medium salinity falls below a certain limit. Ethological and morphological modifications under different salinities are discussed. This experiment shows for the first time the importance of osmotic regulation in the tropical zoanthid P. variabilis.

Este estudo avaliou os efeitos fisiológicos, morfológicos e etológicos no zoantídeo tropical Protopalythoa variabilis em diferentes níveis de salinidade. Para testar a hipótese de osmorregulação, o zoantídeo foi submetido a diferentes variações de salinidade. Os indivíduos foram coletados em recifes de arenito no Nordeste brasileiro e foram levados vivos para o laboratório na água em que foram recolhidos. A capacidade osmorregulatória de P. variabilis foi determinada pela medição da osmolaridade da hemolinfa em diferentes condições de salinidade e comparadas com a osmolaridade do meio. O zoantídeo P. variabilis é um "regulador fraco" visto que osmorregula dentro de uma estreita faixa de valores de salinidade externa e quando a salinidade do meio cai abaixo de um certo limite, ocorre redução da osmolaridade da hemolinfa, aproximadamente em paralelo com a linha isosmótica. As mudanças etológicas e morfológicas em diferentes salinidades são discutidas. Este experimento demonstra pela primeira vez a importância da regulação osmótica no zoantídeo tropical P. variabilis.

High genotypic diversity of the reef-building coral Porites lobata (Scleractinia: Poritidae) in Isla del Coco National Park, Costa Rica / Alta diversidad genotípica del coral constructor de arrecifes Porites lobata (Scleractinia: Poritidae) en el Parque Nacional Isla del Coco, Costa Rica

The isolated Isla del Coco experiences periodic, extreme disturbances which devastate coral reefs surrounding the island. Scleractinian corals build the physical structure of the reef therefore ecosystem recovery relies on coral species recovery. Coral recruits can be of sexual or asexual origin, and the relative success of the two recruit types influences the speed and spread of recovery processes. Here we focus on the massive coral, Porites lobata, because it is the main reef-builder around Isla del Coco to describe the relative contribution of asexual and sexual recruits to population maintenance. P. lobata samples were collected using a spatially explicit random sampling design in three plots at Isla del Coco: Punta Ulloa (n=17), Bahía Weston (n=20) and Punta María (n=20) and samples were genotyped with 11 microsatellite markers. Additional sampling was conducted at three “coastal” sites near the Costa Rican mainland (Isla del Caño Biological Reserve): Caño1 (n=8), Caño2 (n=10), Caño5 (n=11) to compare the contributions of asexual and sexual recruits at Isla del Coco sites to coastal sites. Isla del Coco sites were characterized by small colony size (>60% of colonies <0.5m2) and high sexual reproduction. Sites were either mostly or entirely sexual,consisting of only unique genotypes (N G/N= 0.90-1.00; G O/G E=0.83-1.00; D=0.99-1.00). Although there were no significant differences in genetic diversity (number of alleles per locus, number of private alleles) or colony size between Isla del Coco and the coastal sites, the coastal sites exhibited a greater range of genotypic diversity from moderately asexual (N G/N=0.5; G O/G E=0.36; D=0.8) to purely sexual (N G/N=1.0; G O/G E=1.0; D=1.0). The mode of asexual reproduction in P. lobata is likely fragmentation of adult colonies rather than asexual larval production because ramets of P. lobata occurred close together and asexually produced larvae have not been reported in gonochoric broadcast spawners like P. lobata. Frequent sexual reproduction at Isla del Coco National Park might represent a resource for rapid recovery following extreme El Niño-Southern Oscillation (ENSO) disturbance events. In contrast, larger, asexually-produced fragments rather than smaller, sexually-produced larvae appear to have the advantage at some coastal sites. The high frequency of sexual reproduction at Isla del Coco indicates that not only are sexual partners available but also current conditions are favorable for the delivery of larvae and the rate of predation on small larval recruits must be moderate.

Los ambientes marinos del Parque Nacional Isla del Coco experimentan perturbaciones extremas periódicamente como por ejemplo El Niño-Oscilación del Sur (ENOS) que han devastado las comunidades coralinas. La cobertura coralino se redujo drásticamente durante El Niño de 1982-83. Los corales escleractinios construyen la estructura física de los arrecifes así que la recuperación de estos ecosistemas depende de que los corales se recuperen. Los corales pueden reproducirse sexual y asexualmente, y el éxito relativo de cada forma de reproducción va a guiar el proceso de recuperación con implicaciones potenciales a la diversidad de las comunidades asociadas. En la mayoría de los arrecifes alrededor de la Isla del Coco, el coral masivo, Porites lobata, es la especie constructora predominante. Si la diversidad genotípica (clonal) de esta especie es alta, la diversidad de individuos va a ser más alta resultando en mayor resilencia frente a condiciones ambientales extremas. Alternativamente, una diversidad genotípica baja es indicativo de una estrategia reproductiva asexual posiblemente resultando en el mantenimiento de genotipos bien adaptados aunque la población decline. Aquí, usamos 11 marcadores microsatélite para investigar la contribución relativa de la reproducción sexual o asexual en la recuperación de los arrecifes en el Parque Nacional Isla del Coco. En la Isla del Coco se recolectaron muestras en: Punta Ulloa (n=17), Bahía Weston (n=20) y Punta María (n=20), y para comparar, se recolectaron muestras en localidades cerca de o en la costa continental de Costa Rica; Reserva Biológica Isla del Caño: Caño1 (n=8), Caño2 (n=10) y Caño5 (n=11), y Tres Hermanas, Parque Nacional Marino Ballena (n=4), utilizando un diseño de muestreo espacialmente explícito. Las colonias de la Isla del Coco son generalmente pequeñas (>60% de las colonias <0.5m2) y se observó poca reproducción asexual. En la mayoría de los sitios la reproducción era mayormente sexual (NG/N= 0.90-0.94; GO/GE =0.63-0.74; D=0.99) o totalmente sexual (N G/N= 1.0; G O/G E =1.0; D=1.0), por lo que consiste decolonias con genotipos únicos. En contraste, los sitios costeros tenían un ámbito de predominantemente asexual y genotípicamente pobre (N G/N =0.5; G O/G E =0.11; D=0.5) a totalmente sexual (N G/N= 1.0; G O/G E =1.0; D=1.0). No hubo diferencia en diversidad genética (número de alelos por locus, número de alelos privados) o distribución de tamaño por región. La alta diversidad genotípica del Parque Nacional Isla del Coco indica reproducción sexual frecuente y el potencial para la recuperación rápida de los arrecifes después de perturbaciones severas. En los sitios costeros, la fragmentación asexual de colonias grandes (>2.5m2) y por lo tanto, potencialmente colonias bien adaptadas, puede aumentar las resistencia y resilencia de los sistemas.