ECOLOGIA QUÍMICA MARINHA: ORIGEM, EVOLUÇÃO E PERSPECTIVAS NO BRASIL

MARINE CHEMICAL ECOLOGY: ORIGIN, DEVELOPMENT AND PERSPECTIVES IN BRAZIL. This report reviewed the information about development of marine chemical ecology in Brazil since its origin until May 2011 through analysis of scientific publications and professional formation at different levels. Basic macroalgal studies were predominant, mainly those studies focused on the effect of crude extracts and some pure compounds evaluated as chemical defenses against consumers. The macroalgal approaches also constitute important contributions related to structure and function, intra-population variation, storage and transport of chemical defenses. The number of invertebrate chemical ecology studies although small, verified the presence and activity of secondary metabolites, chemical cues for hosts to associated and chemical defenses in exotic species. Brazilian marine chemical ecology has evolved in accordance to this science in the world, as mostly papers were published in scientific journals of broad accessing. Despite the number of professionals has increased recently, the development of national marine chemical ecology remains slow due to reduced number of PhD formed and that could be head and spread new centers for research and professional formation. Considering the contribution of environmental and genetic factors for the production of chemical cues, the expansion of researches and professional formation, essentially PhDs, must be the basis to understand the pattern of abundance and action of secondary metabolites and their roles in marine community structure. Keywords:  Marine chemical ecology; chemical interactions; chemical defenses; alellopathy.ECOLOGÍA QUÍMICA MARINA: ORIGEN, EVOLUCIÓN Y PERSPECTIVAS EN BRASIL. El presente informe analizó el desarrollo de la ecología química marina en Brasil desde su origen hasta septiembre de 2010, a través del análisis de las publicaciones científicas y de la formación profesional en diferentes niveles. Los estudios básicos con macroalgas fueron predominantes, principalmente aquéllos enfocados en el efecto de extractos y algunas sustancias puras evaluadas como defensas químicas contra consumidores. Los estudios de macroalgas también constituyen importantes contribuciones, relacionadas con la estructura y función, la variación intra-poblacional, el almacenamiento y el transporte de defensas químicas. Sin embargo, el número de estudios de ecología química de invertebrados fue reducido, éstos verificaron la presencia y actividad de metabolitos secundarios, la señalización química para hospederos y defensas químicas en especies exóticas. La ecología química marina brasileña ha evolucionado en consonancia con esta ciencia en el mundo, una vez que predominan las publicaciones en revistas científicas de amplia circulación. A pesar del aumento reciente del número de profesionales en química marina, el desarrollo nacional continua siendo lento debido al número reducido de doctores formados. Considerando la contribución de factores genéticos y ambientales para la producción de señales químicas, la expansión de la investigación y formación profesional, esencialmente de doctores, debe ser la base para la comprensión de los patrones de abundancia y de acción de los metabolitos secundarios y sus funciones en la estructura de las comunidades marinas. Palabras clave: Ecología química marina; interacciones químicas; defensas químicas; alelopatía.Este relatório analisou as informações sobre o desenvolvimento da ecologia química marinha no Brasil desde sua origem até setembro de 2010 através da análise das publicações científicas e formação profissional em diferentes níveis.  Os estudos básicos de macroalgas foram predominantes, principalmente aqueles focados no efeito de extratos e algumas substâncias puras avaliadas como defesas químicas contra consumidores. As abordagens de macroalgas também constituem importantes contribuições relacionadas com a estrutura e função, a variação intra-populacional, armazenamento e transporte de defesas químicas. No entanto, o número de estudos de ecologia química de invertebrados mostrou-se reduzido, os quais verificaram a presença e a atividade de metabólitos secundários, sinalização química para hospedeiros e defesas químicas em espécies exóticas.  A ecologia química marinha brasileira tem evoluído em consonância com esta ciência no mundo, uma vez que predominam as publicações em revistas científicas de ampla circulação. Apesar do número de profissionais da química marinha ter aumentado recentemente, o desenvolvimento nacional continua a ser lento devido ao número reduzido de doutores formados. Considerando a contribuição de fatores genéticos e ambientais para a produção de sinais químicos, a expansão de pesquisas e formação profissional, essencialmente de doutores, deve ser a base para a compreensão do padrão de abundância e de ação dos metabólitos secundários e suas funções na estrutura das comunidades marinhas

Effect of Elatol, Isolated from Red Seaweed Laurencia dendroidea, on Leishmania amazonensis

In the present study, we investigated the antileishmanial activity of sesquiterpene elatol, the major constituent of the Brazilian red seaweed Laurencia dendroidea (Hudson) J.V. Lamouroux, against L. amazonensis. Elatol after 72 h of treatment, showed an IC50 of 4.0 μM and 0.45 μM for promastigote and intracellular amastigote forms of L. amazonensis, respectively. By scanning and transmission electron microscopy, parasites treated with elatol revealed notable changes compared with control cells, including: pronounced swelling of the mitochondrion; appearance of concentric membrane structures inside the organelle; destabilization of the plasma membrane; and formation of membrane structures, apparently an extension of the endoplasmic reticulum, which is suggestive of an autophagic process. A cytotoxicity assay showed that the action of the isolated compound is more specific for protozoa, and it is not toxic to macrophages. Our studies indicated that elatol is a potent antiproliferative agent against promastigote and intracellular amastigote forms, and may have important advantages for the development of new anti-leishamanial chemotherapies

Molecular Mechanisms for Microbe Recognition and Defense by the Red Seaweed Laurencia dendroidea

ABSTRACT The ability to recognize and respond to the presence of microbes is an essential strategy for seaweeds to survive in the marine environment, but understanding of molecular seaweed-microbe interactions is limited. Laurencia dendroidea clones were inoculated with the marine bacterium Vibrio madracius. The seaweed RNA was sequenced, providing an unprecedentedly high coverage of the transcriptome of Laurencia, and the gene expression levels were compared between control and inoculated samples after 24, 48, and 72 h. Transcriptomic changes in L. dendroidea in the presence of V. madracius include the upregulation of genes that participate in signaling pathways described here for the first time as a response of seaweeds to microbes. Genes coding for defense-related transcription activators, reactive oxygen species metabolism, terpene biosynthesis, and energy conversion pathways were upregulated in inoculated samples of L. dendroidea, indicating an integrated defensive system in seaweeds. This report contributes significantly to the current knowledge about the molecular mechanisms involved in the highly dynamic seaweed-bacterium interactions. IMPORTANCE Marine bacteria are part of the healthy microbiota associated with seaweeds, but some species, such as Vibrio spp., are frequently associated with disease outbreaks, especially in economically valuable cultures. In this context, the ability of seaweeds to recognize microbes and, when necessary, activate defense mechanisms is essential for their survival. However, studies dedicated to understanding the molecular components of the immune response in seaweeds are rare and restricted to indirect stimulus. This work provides an unprecedentedly large-scale evaluation of the transcriptional changes involved in microbe recognition, cellular signaling, and defense in the red seaweed Laurencia dendroidea in response to the marine bacterium Vibrio madracius. By expanding knowledge about seaweed-bacterium interactions and about the integrated defensive system in seaweeds, this work offers the basis for the development of tools to increase the resistance of cultured seaweeds to bacterial infections

Trypanocidal action of (−)-elatol involves an oxidative stress triggered by Mitochondria dysfunction

Submitted by Franciele Moreira ([email protected]) on 2018-06-13T15:44:25Z No. of bitstreams: 2 Artigo - Vânia Cristina Desoti - 2012.pdf: 10300592 bytes, checksum: e08312a8af0cb537931b7e8dc2330e95 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2018-06-14T11:39:32Z (GMT) No. of bitstreams: 2 Artigo - Vânia Cristina Desoti - 2012.pdf: 10300592 bytes, checksum: e08312a8af0cb537931b7e8dc2330e95 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-06-14T11:39:33Z (GMT). No. of bitstreams: 2 Artigo - Vânia Cristina Desoti - 2012.pdf: 10300592 bytes, checksum: e08312a8af0cb537931b7e8dc2330e95 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2012Natural compounds have shown good potential for the discovery of new chemotherapeutics for the treatment of Chagas’ disease. Recently, our group reported the effective trypanocidal activity of (−)-elatol, extracted from the red macroalgae Laurencia dendroidea present in the Brazilian coast against Trypanosoma cruzi. However, the mechanism of action of this compound has remained unclear. There are only hypotheses concerning its action on mitochondrial function. Here, we further investigated the mechanisms of action of (−)-elatol on trypomastigotes of T. cruzi. For this, we evaluated some biochemical alterations in trypomastigotes treated with (−)-elatol. Our results show that (−)-elatol induced depolarization of the mitochondrial membrane, an increase in the formation of mitochondrial superoxide anion and loss of cell membrane and DNA integrity. Additionally, (−)-elatol induced formation of autophagic vacuoles and a decrease in cell volume. All together, these results suggest that the trypanocidal action of (−)-elatol involves multiple events and mitochondria might be the initial target organelle. Our hypothesis is that the mitochondrial dysfunction leads to an increase of ROS production through the electron transport chain, which affects cell membrane and DNA integrity leading to different types of parasite death