A Dhb-microcystin from the filamentous cyanobacterium Planktothrix rubescens

Sano, Tomoharu; Takagi, Hiroo; Kaya, Kunimitsu

doi:10.1016/j.phytochem.2004.03.034

Cited by 27 publications

(25 citation statements)

References 11 publications

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“…After the purification procedure, the pure major component of the microcystin exhibited molecular ion obtained by MALDI-TOF at m/z 1024.6 [M + H] + . It was consistent with three previously isolated microcystins: [ d -Asp 3 ]MC–RR (or reported as [ d -Asp 3 , M dha 7 ]MC–RR) [61,62,63], [Dha 7 ]MC–RR [62,63]) and [ d -Asp 3 ,( E )-Dhb 7 ]MC–RR [64,65,66]. The isolation of a sufficient amount of the pure compound enabled extensive NMR spectrometric analyses to differentiate between these derivatives.…”

Section: Discussionsupporting

confidence: 90%

Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

Vasas

Farkas

Borics

et al. 2013

Toxins

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Blooms of toxic cyanobacteria are well-known phenomena in many regions of the world. Microcystin (MC), the most frequent cyanobacterial toxin, is produced by entirely different cyanobacteria, including unicellular, multicellular filamentous, heterocytic, and non-heterocytic bloom-forming species. Planktothrix is one of the most important MC-producing genera in temperate lakes. The reddish color of cyanobacterial blooms viewed in a gravel pit pond with the appearance of a dense 3 cm thick layer (biovolume: 28.4 mm3 L−1) was an unexpected observation in the shallow lake-dominated alluvial region of the Carpathian Basin. [d-Asp3, Mdha7]MC–RR was identified from the blooms sample by MALDI-TOF and NMR. Concentrations of [d-Asp3, Mdha7]MC–RR were measured by capillary electrophoresis to compare the microcystin content of the field samples and the isolated, laboratory-maintained P. rubescens strain. In analyzing the MC gene cluster of the isolated P. rubescens strain, a deletion in the spacer region between mcyE and mcyG and an insertion were located in the spacer region between mcyT and mcyD. The insertion elements were sequenced and partly identified. Although some invasive tropical cyanobacterial species have been given a great deal of attention in many recent studies, our results draw attention to the spread of the alpine organism P. rubescens as a MC-producing, bloom-forming species.

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Section: Discussionsupporting

confidence: 90%

Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

Vasas

Farkas

Borics

et al. 2013

Toxins

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“…Dhb-containing MC-RR variants have been rarely reported, although they were identified in P. agardhii by Sano and Kaya (1995). According to Fastner et al (1999) (Sano et al 2004). Dominance of P. agardhii in the lakes in the present study suggested that the demethylated MC-RR detected might contain Mdha rather than Dhb amino acid residues.…”

Section: Cyanobacteria and Microcystins In Lake Samplesmentioning

confidence: 99%

Cyanobacterial hepatotoxins, microcystins and nodularins, in fresh and brackish waters of the Pomeranian Province, northern Poland

Mazur‐Marzec

Spoof

Kobos

et al. 2008

Oceanological and Hydrobiological Studies

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Microcystins (MCs) and structurally related nodularins (NODs) are hepatotoxic cyclic peptides produced by bloom-forming cyanobacteria. These toxins have been implicated in the deaths of wild and domestic animals as well as in incidents of human illness. Cyanobacterial toxins occurring in the fresh and brackish waters of the Pomeranian Province, northern Poland were characterized in this study. Water samples collected from seven lakes in August and September 2005 were analysed by high performance liquid chromatography (HPLC), enzyme linked immunosorbent assay (ELISA) and protein phosphatase inhibition assay (PPIA). Cyanobacterial toxins present in field samples and in an isolated strain of Planktothrix agardhii were also characterized by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). In most of the fresh water samples MC-LR, MC-RR and MC-3 Corresponding author.

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“…Microcystins consist of more than 100 different variants with molecular weights of 900–1100 Da [2,3,4]. The general structure of microcystins is cyclo(-D-Ala-L-X-D-erythro-β-methylAsp(iso-linkage)-L- Z -Adda-D-Glu(iso-linkage)- N -methyldehydro-Ala) where Adda stands for 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4 E ,6 E -dienoic acid, a unique β-amino acid [5,6,7,8].…”

Section: Introductionmentioning

confidence: 99%

Comparative Cellular Toxicity of Hydrophilic and Hydrophobic Microcystins on Caco-2 Cells

Vesterkvist

Misiorek

Spoof

et al. 2012

Toxins

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Microcystins (MC), cyanobacterial peptide hepatotoxins, comprise more than 100 different variants. They are rather polar molecules but some variants contain hydrophobic amino acid residues in the highly variable parts of the molecule. In MC-LF and MC-LW, the more hydrophobic phenylalanine (F) and tryptophan (W), respectively, have replaced arginine (R) in MC-LR. Depending on the structure, microcystins are expected to have different in vivo toxicity and bioavailability, but only a few studies have considered the toxic properties of the more hydrophobic variants. The present study shows that MC-LF and MC-LW have more pronounced cytotoxic effects on Caco-2 cells as compared to those of MC-LR. Treatment of Caco-2 cells with MC-LW and especially MC-LF showed clear apoptotic features including shrinkage and blebbing, and the cell–cell adhesion was lost. An obvious reduction of cell proliferation and viability, assessed as the activity of mitochondrial dehydrogenases, was observed with MC-LF, followed by MC-LW and MC-LR. Cytotoxicity was quantified by measuring lactate dehydrogenase leakage. The more hydrophobic MC-LW and MC-LF induced markedly enhanced lactate dehydrogenase leakage compared to controls and MC-LR, indicating that the plasma membrane was damaged. All of the three toxins examined inhibited protein phosphatase 1, with MC-LF and MC-LW to a weaker extent compared to MC-LR. The higher toxic potential of the more hydrophobic microcystins could not be explained by the biophysical experiments performed. Taken together, our data show that the more hydrophobic microcystin variants induce higher toxicity in Caco-2 cells.

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A Dhb-microcystin from the filamentous cyanobacterium Planktothrix rubescens

Cited by 27 publications

References 11 publications

Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

Appearance of Planktothrix rubescens Bloom with [D-Asp3, Mdha7]MC–RR in Gravel Pit Pond of a Shallow Lake-Dominated Area

Cyanobacterial hepatotoxins, microcystins and nodularins, in fresh and brackish waters of the Pomeranian Province, northern Poland

Comparative Cellular Toxicity of Hydrophilic and Hydrophobic Microcystins on Caco-2 Cells

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