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Are known cyanotoxins involved in the toxicity of picoplanktonic and filamentous North Atlantic marine cyanobacteria?

Frazão B, Martins R, Vasconcelos V - Mar Drugs (2010)

Bottom Line: Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones.Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain.The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal. bmfrazao@gmail.com

ABSTRACT
Eight marine cyanobacteria strains of the genera Cyanobium, Leptolyngbya, Oscillatoria, Phormidium, and Synechococcus were isolated from rocky beaches along the Atlantic Portuguese central coast and tested for ecotoxicity. Strains were identified by morphological characteristics and by the amplification and sequentiation of the 16S rDNA. Bioactivity of dichloromethane, methanol and aqueous extracts was assessed by the Artemia salina bioassay. Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. Molecular analysis of the genes involved in the production of known cyanotoxins such as microcystins, nodularins and cylindrospermopsin was also performed. Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones. Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.

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Mortality of Artemia salina (%) after 24 and 48 h exposure to dichloromethane extracts at a concentration of 100 mg/mL (C: control).
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f2-marinedrugs-08-01908: Mortality of Artemia salina (%) after 24 and 48 h exposure to dichloromethane extracts at a concentration of 100 mg/mL (C: control).

Mentions: The results concerning the percentage of A. salina mortality exposed to the dichloromethane (Figure 2), the methanolic (Figure 3) and the aqueous extracts (Figure 4), showed that for the dichloromethane extract only the strain LEGE 06008 revealed mortality higher than 50%. Results concerning the methanolic and the aqueous extract were more pronounced for most of the strains, with strains LEGE 06005, LEGE 06010, LEGE 06015 and LEGE 06018 reaching 100% mortality with the aqueous extract. The average 24 h and 48 h LC50 for the methanolic extract were 50.8 mg/mL and 50.2 mg/mL, and the 24 h and 48 h LC50 for aqueous extract were on average 50.7 mg/mL and 50.5 mg/mL, respectively (Table 4).


Are known cyanotoxins involved in the toxicity of picoplanktonic and filamentous North Atlantic marine cyanobacteria?

Frazão B, Martins R, Vasconcelos V - Mar Drugs (2010)

Mortality of Artemia salina (%) after 24 and 48 h exposure to dichloromethane extracts at a concentration of 100 mg/mL (C: control).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2901829&req=5

f2-marinedrugs-08-01908: Mortality of Artemia salina (%) after 24 and 48 h exposure to dichloromethane extracts at a concentration of 100 mg/mL (C: control).
Mentions: The results concerning the percentage of A. salina mortality exposed to the dichloromethane (Figure 2), the methanolic (Figure 3) and the aqueous extracts (Figure 4), showed that for the dichloromethane extract only the strain LEGE 06008 revealed mortality higher than 50%. Results concerning the methanolic and the aqueous extract were more pronounced for most of the strains, with strains LEGE 06005, LEGE 06010, LEGE 06015 and LEGE 06018 reaching 100% mortality with the aqueous extract. The average 24 h and 48 h LC50 for the methanolic extract were 50.8 mg/mL and 50.2 mg/mL, and the 24 h and 48 h LC50 for aqueous extract were on average 50.7 mg/mL and 50.5 mg/mL, respectively (Table 4).

Bottom Line: Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones.Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain.The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biologia, Faculdade de Ciências da Universidade do Porto, Porto, Portugal. bmfrazao@gmail.com

ABSTRACT
Eight marine cyanobacteria strains of the genera Cyanobium, Leptolyngbya, Oscillatoria, Phormidium, and Synechococcus were isolated from rocky beaches along the Atlantic Portuguese central coast and tested for ecotoxicity. Strains were identified by morphological characteristics and by the amplification and sequentiation of the 16S rDNA. Bioactivity of dichloromethane, methanol and aqueous extracts was assessed by the Artemia salina bioassay. Peptide toxin production was screened by matrix assisted laser desorption/ionization time of flight mass spectrometry. Molecular analysis of the genes involved in the production of known cyanotoxins such as microcystins, nodularins and cylindrospermopsin was also performed. Strains were toxic to the brine shrimp A. salina nauplii with aqueous extracts being more toxic than the organic ones. Although mass spectrometry analysis did not reveal the production of microcystins or other known toxic peptides, a positive result for the presence of mcyE gene was found in one Leptolyngbya strain and one Oscillatoria strain. The extensive brine shrimp mortality points to the involvement of other unknown toxins, and the presence of a fragment of genes involved in the cyanotoxin production highlight the potential risk of cyanobacteria occurrence on the Atlantic coast.

Show MeSH
Related in: MedlinePlus