pH-Dependent hydrophobicity of the cyanobacteria toxin microcystin-LR

Maagd, P. Gert-Jan de; Hendriks, A. Jan; Seinen, Willem; Sijm, Dick T.H.M.

doi:10.1016/s0043-1354(98)00258-9

Cited by 175 publications

(97 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Consequently, the combination of these six amino acids within the two variable L amino acid residues would predict the following grading of increasing hydrophobicity: MC RR < MC YR, MC LR < MC LA < MC LW < MC LF, and increasing adhesion capability: MC RR, MC LA, MC LR < MC YR << MC LW < MC LF. The latter theoretical considerations are corroborated by experimentally determined 1 octanol/water partition coeffi cients (log P) for MC LR, LW and LF of 2.16, 3.46 and 3.56, respec tively [26,27] and more importantly by HPLC [28]. (6) MC LF, as also confirmed in this laboratory.…”

Section: Discussionsupporting

confidence: 81%

Pitfalls in microcystin extraction and recovery from human blood serum

Heussner

Altaner

Kamp

et al. 2014

Chemico-Biological Interactions

View full text Add to dashboard Cite

a b s t r a c tBackground: Microcystins (MCs) contaminate water bodies due to cyanobacterial blooms all over the world, leading to frequent exposure of humans to MCs through consumption of meat, fish, seafood, blue green algal products and water, accidental ingestion of contaminated water and scum during recre ational activities and inhalation of cyanobacterial aerosols. For monitoring of human exposure, sensitive screening methods are needed. However, during the analytical process of various matrices, such as human serum, some problems appear to regularly occur during sample preparation and storage, leading to MC loss and thus to underestimation of the true MC concentration. The aim of the current study was therefore to assess the pitfalls of the MC extraction method from human serum with more detail. Methods: Six MC congeners (MC LR, YR, RR, LA, LW, LF) and defined equimolar MC mixtures thereof were spiked into human serum, and quantified using the commercially available Adda ELISA subsequent to standard extraction (methanol extraction with subsequent SPE). To detect the potential influence of sample storage and preparation/storage materials, different types of material such as glass, standard polypropylene and surface treated polypropylene were compared. Results: Loss of MC during preparation and storage is largely dependent on (1) the handling of the stored material, (2) the 'surface' of the storage material and (3) the hydrophobicity of the MCs. Conclusions: The pitfalls described for MC analysis with the ELISA are primarily associated with sample preparation and clean up and thus also apply to other analytical techniques for MC detection beyond the ELISA used. It can be concluded that ELISA based methods are suitable tools for the detection of MCs in human sera and other samples.

show abstract

Section: Discussionsupporting

confidence: 81%

Pitfalls in microcystin extraction and recovery from human blood serum

Heussner

Altaner

Kamp

et al. 2014

Chemico-Biological Interactions

View full text Add to dashboard Cite

show abstract

“…This corresponds to the changes in microcystin hydrophobicity, which was reported to increase as pH decreases (14). These findings clearly demonstrate that hydrophobicity is a contributory factor influencing the initial adsorption of microcystins to the surface of TiO 2 .…”

Section: Resultssupporting

confidence: 61%

Processes influencing surface interaction and photocatalytic destruction of microcystins on titanium dioxide photocatalysts

Lawton

Robertson

Cornish

et al. 2003

Journal of Catalysis

115

View full text Add to dashboard Cite

Microcystins are a family of hepatotoxic peptides produced by freshwater cyanobacteria. Their occurrence in drinking water is of concern since chronic exposure to these toxins causes tumour promotion. It is therefore essential to establish a reliable treatment strategy that will ensure their removal from potable water. We have previously described the rapid destruction of microcystin-LR using TiO 2 photocatalysis, however, since there are at least 70 microcystin variants it is essential that the destruction of a number of microcystins be evaluated. In this study the dark adsorption and destruction of four microcystins was followed over a range of pH. All four microcystins were destroyed although the efficiency of their removal varied. The two more hydrophobic microcystins (-LW and -LF) were found to have high dark adsorption (98 and 91% at pH 4) in contrast to microcystin-RR, which was found to have almost no (only 2-3%) dark adsorption across all pH.

show abstract

“…Lahti and Hiisvirta (1989) indicated that the concentrations of MCs hardly changed when small doses of powdered ACs were added, but Donati et al (1994) reported that the removal of MCs was a direct proportionality of ACs mesopore volume. Furthermore the decrease of pH was found to cause the increase in the adsorption of MCs by ACs (Pendleton et al, 2001), which is in accordance with the properties that the solubility of MC-LR in water was decrease with the increase of pH (De Maagd et al, 1999). In order to keep the stable pH, the phosphate buffer (pH 7.0) solution was adopted as reaction solution in the experiment.…”

Section: Adsorption Of Mcs By Cnts Acs and Clayssupporting

confidence: 69%

Adsorption of microcystins by carbon nanotubes

et al. 2006

View full text Add to dashboard Cite

The production of cyanobacterial toxins microcystins (MCs) by cyanobacterial bloom which may promote the growth of tumor in human liver is a growing environmental problem worldwide. In this paper, the adsorption of MC-RR and LR, which were extracted from cyanobacterial cells in Dianchi Lake in China, by carbon nanotubes (CNTs), wood-based activated carbon (ACs) and clays were investigated. Compared with ACs and clay materials of sepiolite, kaolinite and talc tested, CNTs were found to have a strong ability in the adsorption of MCs. At the concentrations of 21.5 mg l À1 MC-RR and 9.6 mg l À1 MC-LR in 50 mmol phosphate buffer solution (pH 7.0), the adsorption amounts of MCs by CNTs with the range of outside diameter from 2 to 10 nm were 14.8 and 5.9 mg g À1 , which were about four times higher than those by other adsorbents tested. It was shown that with the decrease of CNTs outside diameters from 60 to 2 nm, the adsorption amount of MCs was apparently increased, however the size of CNTs particles formed in solution declined. This result implies that the size of CNTs tube pore that is fit for the molecular dimension of MCs plays a dominant role. Furthermore the specific surface area of CNTs was also found to be a factor in the adsorption of MCs. The results suggested that the selection of suitable size of CNTs as a kind of adsorbent is very important in the efficient eliminating MCs from drinking water in future.

show abstract

pH-Dependent hydrophobicity of the cyanobacteria toxin microcystin-LR

Cited by 175 publications

References 19 publications

Pitfalls in microcystin extraction and recovery from human blood serum

Pitfalls in microcystin extraction and recovery from human blood serum

Processes influencing surface interaction and photocatalytic destruction of microcystins on titanium dioxide photocatalysts

Adsorption of microcystins by carbon nanotubes

Contact Info

Product

Resources

About