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1.
Harmful Algae ; 96: 101846, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32560831

RESUMO

Harmful algae blooms (HABs) are characterized for the coexistence of phytoplankton species with dynamic and complex biotic interactions (e.g., competition, symbiosis, predation, parasitism, allelopathy), that occur at fine temporal and spatial scales, and are relevant to understand the role that different species of phytoplankton play in the regulation of HABs. In this work the allelopathic effects of Margalefidinium polykrikoides (=Cochlodinium polykrikoides) and Gymnodinium impudicum on Gymnodinium catenatum were evaluated. The allelopathic abilities of M. polykrikoides and G. impudicum were investigated in bi-algal culture experiments and in trials in which target species were co-cultured, separated by a 10 µm membrane to prevent a direct cell-to-cell contact; and also by the addition of different volumes of culture media without cells. For all trials, cells of each species were harvested during exponential phase and cultured together by triplicate at three relative abundances: 1:1 (200 Cells mL-1 of each species, G. catenatum and M. polykrikoides or G. impudicum), 2:1 (400 Cells mL-1 of G. catenatum and 200 Cells mL-1 of M. polykrikoides or G. impudicum), and 1:2 (200 cells mL-1 of G. catenatum and 400 Cells mL-1 of M. polykrikoides or G. impudicum). All bioassays were carried out by triplicate in 250 mL Erlenmeyer flasks with 150 mL of modified GSe medium with an initial inoculum of 200 or 400 Cells mL-1. During experiments G. catenatum abundances were enumerated daily. In bi-algal culture experiments mortalities of G. catenatum were from 50% to 100% after 48 h of cell contact with M. polykrikoides or G. impudicum. In the case of culture media without cells, only M. polykrikoides caused a decrease in the cell abundance and growth rate of G. catenatum. Morphological changes occurred in G. catenatum when in contact with M. polykrikoides and G. impudicum, such as membrane shedding, prominent nucleus, loss of flagella, cell lysis, as well as the separation of long chains into individual cells. These results suggest that in the natural environment M. polykrikoides and G. impudicum have allelopathic interactions in G. catenatum, which could negatively affect its growth and survival, indicating that these species could displace blooms of G. catenatum.

2.
Harmful Algae ; 51: 1-9, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28003057

RESUMO

The allelopathic effect of the raphidophyte Chattonella marina var. marina on the dinoflagellate Gymnodinium catenatum was determined. Both species are harmful algal bloom forming algae, produce toxic metabolites, and can co-exist in the environment. In general, raphidophytes tend to dominate over dinoflagellates, which may indicate an allelopathic effect of the former algae. Strains of C. marina var. marina and G. catenatum isolated from Bahía de La Paz were cultured in bi-algal cultures with and without cell contact. Additionally, cultures of G. catenatum were exposed to cell-free culture filtrates of the raphidophyte to test whether soluble allelopathic molecules are active. During late stationary phase, both species were cultivated in mixed cultures for 72h using the following cell abundance proportions: 20×103cellsL-1: 20×103cellsL-1 (1:1; G. catenatum: C. marina); 10×103cellsL-1: 20×103cellsL-1 (1:2), and 20×103cellsL-1: 10×103cellsL-1 (2:1). Cells of G. catenatum were also exposed to different volumes of cell filtrates of C. marina (10, 20, and 50mL) using the same cell abundance proportions for 24h. Samples were taken daily for cell counts and microscopic observations. Growth inhibition was higher when there was cell contact between both species, however mortality of G. catenatum was also observed without direct cell contact, indicating that toxic metabolites are liberated to the culture medium. Changes in cell morphology of G. catenatum occurred in the presence of cells and filtrates of C. marina, such as loss of flagella and motility, swelling, loss of girdle and sulci, prominent nucleus, rupture of cell membrane, and cell lysis. Induction of temporary cysts was also observed. These results suggest that toxic metabolites are liberated to the medium by C. marina, affecting G. catenatum by inhibiting its growth and causing changes in its life history, providing new insights of interactions between raphidophytes and dinoflagellates that could happen in the natural environment when both species are present.

3.
Methods Mol Biol ; 1308: 421-35, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26108522

RESUMO

The development of novel environmentally friendly antifouling (AF) solutions is a very active field in fundamental and applied research. An attractive option in producing such material resides in biomimetic studies: living organisms have evolved well-adapted structures and materials over geological times through natural selection. In this chapter, we explain the experimental procedure to be followed for the preparation of macroalgal extracts and to assess their AF efficiency towards key species. All bioassays described here have the advantage of being fast, reliable, and standardized.


Assuntos
Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Incrustação Biológica/prevenção & controle , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/farmacologia , Alga Marinha/química , Animais , Bactérias/efeitos dos fármacos , Aderência Bacteriana/efeitos dos fármacos , Bioensaio/métodos , Microalgas/efeitos dos fármacos , Testes de Sensibilidade Microbiana/métodos , Mytilus edulis/efeitos dos fármacos , Mytilus edulis/fisiologia , Ulva/efeitos dos fármacos , Ulva/fisiologia
4.
J Nat Prod ; 71(4): 608-14, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18288806

RESUMO

The chemical study of a sponge of the genus Axinyssa collected in the Gulf of California has led to the isolation of the new bicyclic sesquiterpenes axinisothiocyanates A-L ( 1- 12) together with the known compounds (1 R,6 S,7 S,10 S)-10-isothiocyanato-4-amorphene ( 13), (4 R*,5 R*,7 S*,10 R*)-4-isocyanoeudesm-11-ene, (-)-epipolasin A, and (+)-aristolone. The structures of the new metabolites have been established by spectroscopic techniques, including the analysis of pyridine-induced 1H NMR chemical shifts. The cytotoxic activity has been tested against three human tumor cell lines.


Assuntos
Antineoplásicos/isolamento & purificação , Isotiocianatos/isolamento & purificação , Poríferos/química , Sesquiterpenos/isolamento & purificação , Animais , Antineoplásicos/química , Antineoplásicos/farmacologia , California , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Isotiocianatos/química , Isotiocianatos/farmacologia , Estrutura Molecular , Oceanos e Mares , Sesquiterpenos/química , Sesquiterpenos/farmacologia
5.
Bioorg Med Chem ; 15(15): 5275-82, 2007 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-17512741

RESUMO

The chemical study of the sponge Aplysina gerardogreeni collected at the Gulf of California has led to the isolation of four new dibromotyrosine-derived metabolites, aplysinones A-D, whose structures were determined by spectroscopic analysis and chemical methods. The new compounds and four semisynthetic analogues prepared in this study have shown cytotoxic activity against human tumor cell lines.


Assuntos
Antineoplásicos/farmacologia , Poríferos/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo , Animais , Antineoplásicos/química , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Humanos
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