Colorimetric test for the monitoring of microcystins in cyanobacterial culture and environmental samples from southeast - Brazil

Abstract

Microcystins are hepatotoxic heptapeptides produced by some cyanobacterial genera under determined physico-chemical conditions in the environment, which are responsible for the intoxication and death of animals and humans. The detection of microcystins in potable water or recreational water is not carried out routinely in the majority of Brazilian states. The protein phosphatase 1 (PP1) inhibition test is a simple, rapid and reproducible colorimetric method. The applicability of the PP1 inhibition test was tested using Microcystis aeruginosa (strain 1, UFRJ-toxin producer) grown under controlled light and temperature condition (12/12h light/dark using 30 μE.m 2 .s -1 at 23ºC) in a bioreactor. The total concentrations of P (24, 6 and 4 μM) and Fe (4 and 1 μM) were varied in ASM-1medium and their effects on the growth rates and toxin production were analyzed. A standard curve of PP1 inhibition by microcystin-LR reached detection limit of 0.01 ng.mL . Under the highest concentrations of P (24 μM) and Fe (4 μM), the production of microcystin was detected throughout the growth experiment. The highest concentration of microcystin was observed at 6 μM P while at 1 μM Fe, PP1 inhibition was not detected. Samples from environmental blooms in water reservoirs used for human and animal consumption, from southeast Brazil (Belo Horizonte/MG), were tested and quantified for microcystin presence by the PP1 colorimetric test. The concentration of microcystin varied from undetectable to 100 ng.mL -1 in the environmental samples with Microcistis flos-aquae as the predominant cyanobacterial strain.

Emerging (Bio)Sensing Technology for Assessing and Monitoring Freshwater Contamination - Methods and Applications

“…They are presented in table 2 (Almeida et al, 2006;Allum et al, 2008;Dawan et al, 2011;Ding & Mutharasan, 2010;Gregora & Marsálek, 2005;Hu et al, 2008;Lindner et al, 2009;Long et al, 2009Long et al, , 2010Loypraseta et al, 2008;Pyo et al, 2005Pyo et al, , 2006Pyo & Jin, 2007;Queirós et al, 2011;Sheng et al, 2007;Xia et al, 2010Xia et al, , 2011Zhang et al, 2007). Optical immuno-based techniques are by large the most widely techniques that have been developed for the detection of MCs Hu et al, 2008;Long et al, 2010;Loypraseta et al, 2008;Pyo et al, 2005Pyo et al, , 2006Pyo & Jin, 2007;Sheng et al, 2007;Xia et al, 2010).…”

“…The Adda (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid) group of MCs is responsible by the infiltration of toxins in the liver cells where MCs irreversibly bind to serine/threonine protein phosphatases type 2A enzymatic activity (Almeida et al, 2006;. These enzymes are involved on the dephosphorylation of proteins.…”

Degradation of cyanotoxins (microcystin) in drinking water using photoelectrooxidation

“…The main toxic cyanobacteria genera are Anabaena, Aphanizomenon, Nodularia and Microcystis, which produce a hepatotoxin that is hazardous for human beings and responsible for animal deaths (Moreira et al, 2011). Microcystins are cyclic-heptapeptides, characterised by an unusual amino acid residue, which is affects the toxicity of the heptapeptide (Almeida et al, 2006).…”

“…This limit in treated drinking water has been globally accepted. Brazil included this limit in legislation in 2004 (Almeida et al, 2006). In this scenario, several techniques have been developed to remove cyanobacterial cells and to degrade cyanotoxins.…”

In situ bacterial mitigation of the toxic cyanobacterium Microcystis aeruginosa: implications for biological bloom control

“…Cyanobacterial blooms can also lead to the production of microcystins (MCs) that can be toxic to aquatic organisms including fish, birds, wild animals, livestock, waterfowl, as well as to humans (Carmichael et al 1975;Codd et al 1989;Jacquet et al 2004;Ernst et al 2006;Palikova et al 2007). MCs are also associated with allergies, irritant reactions, gastroenteritis, liver disease, and tumors in humans (An and Carmichael 1994;Bell and Codd 1994;Dawson 1998;Almeida et al 2006). Direct application of chemicals to control algal blooms can harm aquatic ecosystems by killing beneficial organisms such as plankton and fish (McGuire et al 1984;Reynolds 1984;Reyssac and Pletikosic 1990).…”