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Published on: February 7, 2017
Microcystins from Anabaena flos-aquae NRC 525-17
Abstract:
Anabaena flos-aquae NRC 525-17 produces a very potent neurotoxin, anatoxin-a(s). During isolation of the neurotoxin, we found that the strain contains four other toxic compounds which show strong hepatotoxicity. The four toxins, toxins 1, 1', 2, and 3, were successfully purified. Toxin 2, one of major toxins, was identified as 3-desmethylmicrocystin LR (1) by comparison of spectral data of the known compound. Since the three other toxins contain an unknown amino acid, GC/MS was applied and it revealed the presence of homotyrosine in toxins 1 (2) and 1' (3). Only a partial structure was obtained for toxin 3 due to the small amount present in the cells.
Insights
The cyanobacterium Anabaena flos-aquae NRC 525-17 produces anatoxin-a(s) neurotoxin and four potent hepatotoxic compounds. Researchers identified 3-desmethylmicrocystin LR and homotyrosine in these newly discovered toxins.
Area of Science:
- * Cyanobacterial toxinology and natural product chemistry.
- * Environmental microbiology and aquatic toxicology.
Background:
- * Anabaena flos-aquae NRC 525-17 is known to produce the potent neurotoxin anatoxin-a(s).
- * The presence of other co-occurring toxins in this strain was previously uncharacterized.
Purpose of the Study:
- * To investigate and characterize additional toxic compounds produced by Anabaena flos-aquae NRC 525-17 beyond anatoxin-a(s).
- * To determine the chemical structures of novel hepatotoxic compounds isolated from the cyanobacterial strain.
Main Methods:
- * Isolation and purification of toxic compounds using chromatographic techniques.
- * Structure elucidation employing mass spectrometry (GC/MS) and comparison of spectral data.
- * Identification of known compounds by matching spectral data with existing literature.
Main Results:
- * Four novel hepatotoxic compounds, designated toxins 1, 1', 2, and 3, were isolated and purified.
- * Toxin 2 was identified as 3-desmethylmicrocystin LR.
- * Homotyrosine, an uncommon amino acid, was identified in toxins 1 and 1' using GC/MS.
Conclusions:
- * Anabaena flos-aquae NRC 525-17 produces a complex mixture of toxins, including both neurotoxins and hepatotoxins.
- * The discovery of 3-desmethylmicrocystin LR and homotyrosine-containing peptides highlights the chemical diversity of cyanobacterial secondary metabolites.
- * Further research is needed to fully elucidate the structure of toxin 3 and assess the ecological and toxicological significance of these compounds.
