Toxic Peptide From Palythoa caribaeorum Acting on the TRPV1 Channel Prevents Pentylenetetrazol-Induced Epilepsy in Zebrafish Larvae

PcActx peptide, identified from the transcriptome of zoantharian Palythoa caribaeorum, was clustered into the phylogeny of analgesic polypeptides from sea anemone Heteractis crispa (known as APHC peptides). APHC peptides were considered as inhibitors of transient receptor potential cation channel subfamily V member 1 (TRPV1). TRPV1 is a calcium-permeable channel expressed in epileptic brain areas, serving as a potential target for preventing epileptic seizures. Through in silico and in vitro analysis, PcActx peptide was shown to be a potential TRPV1 channel blocker. In vivo studies showed that the linear and oxidized PcActx peptides caused concentration-dependent increases in mortality of zebrafish larvae. However, monotreatment with PcActx peptides below the maximum tolerated doses (MTD) did not affect locomotor behavior. Moreover, PcActx peptides (both linear and oxidized forms) could effectively reverse pentylenetetrazol (PTZ)-induced seizure-related behavior in zebrafish larvae and prevent overexpression of c-fos and npas4a at the mRNA level. The excessive production of ROS induced by PTZ was markedly attenuated by both linear and oxidized PcActx peptides. It was also verified that the oxidized PcActx peptide was more effective than the linear one. In particular, oxidized PcActx peptide notably modulated the mRNA expression of genes involved in calcium signaling and γ-aminobutyric acid (GABA)ergic-glutamatergic signaling, including calb1, calb2, gabra1, grm1, gria1b, grin2b, gat1, slc1a2b, gad1b, and glsa. Taken together, PcActx peptide, as a novel neuroactive peptide, exhibits prominent anti-epileptic activity, probably through modulating calcium signaling and GABAergic-glutamatergic signaling, and is a promising candidate for epilepsy management.

Branqueamento de corais e outros cnidários bentônicos no costão rochoso da Praia do Forno (Arraial do Cabo, RJ) durante as anomalias térmicas das águas superficiais do oceano ocorridas nos meses de fevereiro e maio de 2019

O presente estudo objetiva descrever as ocorrências de branqueamentos dos corais e de outros cnidários bentônicos no costão rochoso da Praia do Forno (Arraial do Cabo, RJ), observadas em fevereiro (verão) e maio (outono) de 2019, relacionando-as com possíveis eventos de aquecimento das águas superficiais do oceano. As cartas de anomalias térmicas foram obtidas pelo INMET e os trabalhos de campo foram desenvolvidos baseados no Protocolo AGRRA. Foram utilizados dois transectos de 10 m de comprimento, colocados de forma contínua e paralelos ao eixo maior do costão rochoso, onde foram distribuídos quadrats de 36X36 cm, nas posições demarcadas em: 1, 3, 5, 7 e 9 m ao longo destes transectos e fotografados para obtenção dos dados. Foram calculados: o número total de colônias, número de colônias branqueadas e a média da área de cada espécie de cnidário bentônico afetada por diferentes intensidades de branqueamento (fraco ou forte). Quatro espécies de cnidários bentônicos foram identificadas, dentre estas, Millepora alcicornis e Palythoa caribaeorum sofreram branqueamento forte e fraco, com aumento principalmente do branqueamento forte no mês de maio – período antecedido, por anomalia térmica de valor 2,0 oC durante todo o mês de março e na segunda quinzena de abril; enquanto Siderastrea stellata e Zoanthus sp. não sofreram branqueamento.

Antimicrobial activity of bacteria isolated from tissue of the coral Palythoa caribaeorum (Zoantharia: Sphenopidae) from Paraíba, Brazil coastal reefs

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.

The impacts of competitive interactions on coral colonies after transplantation: a multispecies experiment from the Florida Keys, US

Reef restoration programs in Florida, US, focused initially on Acropora, but there is now a need to include other species that have also experienced declines. An outplanting experiment using Acropora cervicornis, Montastraea cavernosa, and Orbicella faveolata was conducted to compare performance among species and evaluate the impacts of contact interactions with macroalgae and the zoanthid Palythoa caribaeorum. Montastraea cavernosa and O. faveolata showed high survivorship (78% and 92%, respectively) over 18 mo. However, surviving colonies had limited growth and lost tissue due to factors like predation and disease. In contrast, A. cervicornis showed exponential growth. Colonies in contact with macroalgae showed the lowest survivorship. Removing macroalgae provided no long-term benefits in growth and a slight improvement in colony survivorship. Acropora cervicornis in contact with Palythoa grew 45% less than controls. Our study showed that: (1) coral taxa with massive morphologies (40–130 cm2) can be transplanted with low colony mortality but that their slow growth is not enough to balance partial tissue mortality caused by multiple chronic stressors; (2) removal of macroalgae at the time of outplanting improves colony survivorship; (3) periodic removal of macroalgae does not enhance growth; and (4) contact with Palythoa should be avoided. The impacts of contact competition were variable among species with different colony morphologies, with A. cervicornis showing the highest susceptibility to competition from algae and Palythoa. While restoration can rapidly increase coral abundance, long-term success will require a multifaceted approach to reduce the impacts of chronic reef stressors on wild and outplanted corals alike.

Registro de petróleo em poríferos e cnidários durante o impacto agudo de derramamento no Nordeste brasileiro em 2019

Toneladas de petróleo atingiram centenas de localidades ao longo da costa nordestina brasileira entre agosto e dezembro de 2019. A mídia enfatizou o impacto apenas para os vertebrados de grande porte ou com apelo midiático, e algumas pesquisas acadêmicas foram feitas com foco em espécies de interesse comercial, não contemplando outras espécies que também podem ter sido afetadas, em especial os invertebrados bentônicos sésseis ou de pouca mobilidade. Este trabalho teve como objetivos conferir a existência de resquícios de óleo em uma praia urbana da cidade após a limpeza feita por voluntários e funcionários de órgãos governamentais e investigar a ocorrência de petróleo em algumas espécies de poríferos e cnidários comuns nos afloramentos rochosos do litoral de Salvador. Após a limpeza feita por voluntários e órgãos governamentais. Os exemplares coletados foram identificados e necropsiados sob lupa. Como resultado das observações de campo verificou-se que, mesmo após a limpeza, a praia continuava apresentando diversos vestígios de óleo na areia, nas rochas e também nas algas. Foram identificadas quatro espécies de Porifera (Amphimedon viridis, Cinachyrella apion, Cliona varians e Desmapsamma anchorata) e quatro de Cnidaria (Bellactis ilkaliaseae, Bunodosoma cangicum, Palythoa caribaeorum e Zoanthus sociatus), sendo encontrados vestígios de petróleo na espongiocele de D. anchorata e na faringe de B. ilkaliaseae. Tais registros ampliam o número de taxa afetados pelo impacto agudo após o evento de derramamento de óleo no Nordeste em 2019.