Phylum BX. Cyanobacteria

Castenholz, Richard W.; Wilmotte, Annick; Herdman, Michael; Rippka, Rosmarie; Waterbury, John; Iteman, Isabelle; Hoffmann, Lucien

doi:10.1007/978-0-387-21609-6_27

Cited by 274 publications

(158 citation statements)

References 16 publications

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“…strain PCC 9240 is relatively large in diameter (<8 mm) and synthesizes phycoerythrin, while the other six toxin-producing strains exhibit narrower trichomes (4-5 mm diameter) and lack phycoerythrin. These morphotypes correspond respectively to Oscillatoria clusters 2 and 4 as defined previously (Rippka & Herdman, 1992;Castenholz et al, 2001), frequently found in aquatic and terrestrial environments (R. Rippka, unpublished observations) and of widespread geographical distribution. Therefore, neurotoxicity can be correlated neither with taxonomic entities nor with the geographical origin of the strains, this class of toxins having been detected in isolates from Scandinavia, The Netherlands and the USA (Tables 1 and 2).…”

Section: Discussionsupporting

confidence: 80%

Neurotoxins in axenic oscillatorian cyanobacteria: coexistence of anatoxin-a and homoanatoxin-a determined by ligand-binding assay and GC/MS

et al. 2005

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Two neurotoxic alkaloids, anatoxin-a and its homologue homoanatoxin-a, were purified from the filamentous cyanobacteria Oscillatoria sp. strain 193 (PCC 9240) and Oscillatoria formosa NIVA CYA-92 (PCC 10111), respectively, and characterized by mass spectrometry. Biological activity was determined by examining the capacity of the toxins to competitively inhibit the binding of radiolabelled bungarotoxin to acetylcholine receptors, using post-synaptic membrane fractions of Torpedo electric tissue. Inhibition was concentration dependent, with a K i of 5?4±1?1610 "8 M for anatoxin-a and 7?4±0?9610 "8 M for homoanatoxin-a. Their high affinities for the nicotinic cholinergic receptors were exploited to adapt the radioligand-binding assay for routine detection of this class of neurotoxins directly in low-molecular-mass cell extracts of cyanobacteria. Confirmation of the results and toxin identification were achieved by coupled gas chromatography-mass spectrometry (GC/MS). Seventy-six axenic strains, representative of 13 genera, were analysed. Five strains of the genus Oscillatoria, hitherto unknown for their toxicity, inhibited bungarotoxin binding. GC/MS revealed that Oscillatoria sp. strains PCC 6407, PCC 6412 and PCC 9107 synthesized exclusively anatoxin-a, whereas both anatoxin-a and homoanatoxin-a were produced by strain PCC 9029. Oscillatoria sp. strain PCC 6506, an isolate co-identic with strain PCC 9029, also produced both neurotoxins, but their respective presence depended upon growth conditions. The latter results suggest that regulatory differences in at least some of the cyanobacterial strains may account for the preferential synthesis of only one of the two neurotoxins or for their simultaneous occurrence. INTRODUCTIONWorldwide proliferation of cyanobacterial blooms constitutes a serious environmental and economic problem that menaces wildlife and human health. Bloom development, a phenomenon related to water eutrophication, is favoured by the ability of planktonic cyanobacteria to synthesize gas vesicles that allow them to float to the surface layers of the water column. The massive growth and accumulation of cyanobacteria greatly impair food-web dynamics and the physico-chemical factors inside a given aquatic ecosystem. Moreover, many cyanobacteria are able to produce potent hepatotoxins such as microcystin, cylindrospermopsin and nodularin, and/or neurotoxins such as anatoxin-a, homoanatoxin-a, anatoxin-a(s) and saxitoxin (Carmichael, 1994;Sivonen & Jones, 1999).Anatoxin-a (ANTX) (2-acetyl-9-azabicyclo[4.2.1]non-2-ene) and its methylene homologue homoanatoxin-a (HANTX) (2-(propan-1-oxo-1-yl)-9-azabicyclo[4.2.1]non-2-ene) (Devlin et al., 1977;Skulberg et al., 1992), are lowmolecular-mass bicyclic secondary amines synthesized by some planktonic and benthic strains of the genera Anabaena, Oscillatoria, Aphanizomenon and Cylindrospermum (Sivonen et al., 1989(Sivonen et al., , 1990. At nanomolar levels, ANTX is a specific cholinergic agonist whose potency relies upon its high affinity for the nicotinic acet...

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Section: Discussionsupporting

confidence: 80%

Neurotoxins in axenic oscillatorian cyanobacteria: coexistence of anatoxin-a and homoanatoxin-a determined by ligand-binding assay and GC/MS

et al. 2005

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“…3) (Castenholz, 2001). clustering within the Nostocales, of which several genera were 312 paraphyletic (Fig.…”

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confidence: 99%

Polyphasic identification of cyanobacterial isolates from Australia

Lee¹,

Ryan²,

Monis³

et al. 2014

Water Research

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22Reliable identification of cyanobacterial isolates has significant 23 socio-economic implications as many bloom-forming species 24 affect the aesthetics and safety of drinking water, through the 25 production of taste and odour compounds or toxic metabolites. 26The limitations of morphological identification have promoted 27 the application of molecular tools, and encouraged the adoption 28 of combined (polyphasic) approaches that include both 29 microscopy-and DNA-based analyses. In this context, the 30 rapid expansion of available sequence data is expected to allow 31 increasingly reliable identification of cyanobacteria, and 32 ultimately resolve current discrepancies between the two 33 approaches. 34In the present study morphological and molecular 35 characterisations of cyanobacterial isolates (n=39), collected 36 from various freshwater sites in Australia, were compared. 37Sequences were obtained for the small ribosomal subunit RNA 38 gene (16S rDNA) (n=36), the DNA-dependent RNA 39 polymerase gene (rpoC1) (n=22), and the phycocyanin operon, 40 with its intergenic spacer region (cpcBA-IGS) (n= 19).

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“…(Castenholz, 2001; Komárek et al, 2003) A phylogenetic analysis, using a 1.2 kb partial sequence of 16S rDNA, was performed to assist the taxonomic identification and indicated that UIC 10445 was a member of the Lyngbya wollei clade. A very recently published report revealed that cyanobacteria previously identified as L. wollei were distinct from the other freshwater species of the genus Lyngbya and that these cyanobacteria should be considered a separate genus described as Microseira .…”

Section: Resultsmentioning

confidence: 99%

Microseiramide from the freshwater cyanobacterium Microseira sp. UIC 10445

Luo

Krunić

Chlipala

et al. 2015

Phytochemistry Letters

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Microseiramide (1), a cyclic heptapeptide, was isolated from a sample of the freshwater cyanobacterium Microseira sp. UIC 10445 collected in a shallow lake in Northern Indiana. Taxonomic identification of UIC 10445 was performed by a combination of morphological and phylogenetic characterization. Phylogenetic analysis revealed that UIC 10445 was a member of the recently described genus Microseira, which is phylogenetically distinct from the morphologically similar genera. Moorea and Lyngbya. The planar structure of microseiramide (1) was determined by extensive 1D and 2D NMR experiments as well as HRESIMS analysis. The absolute configurations of amino acid residues were determined using acid hydrolysis followed by the advanced Marfey's analysis. microseiramide (1) is the first cyclic peptide reported from a Microseira sp., and the structure of microseiramide (1) is distinct from the previously known metabolites from cyanobacteria of the genera Moorea and Lyngbya.

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Phylum BX. Cyanobacteria

Cited by 274 publications

References 16 publications

Neurotoxins in axenic oscillatorian cyanobacteria: coexistence of anatoxin-a and homoanatoxin-a determined by ligand-binding assay and GC/MS

Neurotoxins in axenic oscillatorian cyanobacteria: coexistence of anatoxin-a and homoanatoxin-a determined by ligand-binding assay and GC/MS

Polyphasic identification of cyanobacterial isolates from Australia

Microseiramide from the freshwater cyanobacterium Microseira sp. UIC 10445

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