Highly sensitive detection and discrimination of LR and YR microcystins based on protein phosphatases and an artificial neural network

Abstract

The inhibition characteristics of three different protein phosphatases by three microcystin (MC) variants--LR, YR, and RR--were studied. The corresponding K (I) for each enzyme-MC couple was calculated. The toxicity of MC varies in the following order: MC-LR > MC-YR > MC-RR. The sensitivity of the enzymes increased in the following order: mutant PP2A < mutant PP1 < natural PP2A. The best limit of detection obtained was 21.2 pM MC-LR using the most sensible enzyme. Methanol, ethanol, and acetonitrile up to 2 % (v/v) may be used in inhibition measurements. An artificial neural network (ANN) was used to discriminate two MC variants--LR and YR--using the differences in inhibition percentages measured with mutant PP1 and natural PP2A. The ANN is able to analyze mixtures with concentrations ranging from 8 to 98 pM MC-LR and 31 to 373 pM MC-YR.

Micro-droplet Hydrodynamic Voltammetry for the Determination of Microcystin-LR Based on Protein Phosphatase

“…Mouse bioassay was the first screening method to detect MC-LR [8,9]. The commonly used methods are immunoassays [10], whole cell bioassays [11], protein phosphatase inhibition assays (PPIA) [12][13][14][15], high-performance liquid chromatography (HPLC) [16], and liquid chromatography-mass spectrometry (LC-MS) [17] etc. Mouse bioassay is suitable to get the sample toxicity indication.…”

Bioelectronic Tongues Employing Electrochemical Biosensors

“…26 Cross-response features use of protein phosphatases included in the study towards microcystins LR, YR and RR. Adapted from data in [78] Bioelectronic Tongues Employing Electrochemical Biosensors field, in the determination of emerging pollutants as it can be inhibitors of serotonin uptake receptors, that is, the new antidepressants Prozac and related drugs.…”

“…In a very recently published work during the writing of this chapter, the idea was put into practice, coupling amperometric biosensors based on lactate oxidase, sarcosine oxidase and mixture of fumarase and sarcosine oxidase that were used for monitoring of organic acids like tartaric, malic and lactic in wine samples [76], with correct comparison against standard HPLC methods. In a recent work in J. L. Marty Laboratory in Perpignan, France, a BioET system was conceived to determine high-priority pollutants, LR and YR microcystins, based on inhibition of protein phosphatases [78]. Microcystins (MC) are generated during algal blooms of toxic cyanobacteria (blue-green algae) representing a serious problem because of the potent toxins that can be released.…”

Biosensor based on inhibition of monoamine oxidases A and B for detection of β-carbolines

“…The differences between the inhibition percentages produced by different inhibitors on several enzyme isoforms may be used for the creation of an artificial neural network (ANN) that can discriminate between different analytes: e.g. two microcystin variants (LR and YR) were analyzed from mixtures using the differences in inhibition percentages measured with a mutant and the wild type protein phosphatase [24]. Even easier, the presence of an inhibitor can be discriminated in complex samples when only one enzyme is inhibited by the analyte: e.g.…”