Recent developments in the methods of quantitative analysis of microcystins

Abstract

Cyanotoxins are produced by the toxic cyanobacterial species present in algal blooms formed in water bodies due to nutrient over-enrichment by human influences and natural environmental conditions. Extensive studies are available on the most widely encountered cyanotoxins, microcystins (MCs) in fresh and brackish water bodies. MC contaminated water poses severe risks to human health, environmental sustainability, and aquatic life. Therefore, commonly occurring MCs should be monitored. Occasionally, detection and quantification of these toxins are difficult due to the unavailability of pure standards. Enzymatic, immunological assays, and analytical techniques like protein phosphatase inhibition assay, enzymelinked immunosorbent assay, high-performance liquid chromatography, liquid chromatography-mass spectrometry, and biosensors are used for their detection and quantification. There is no single method for the detection of all the different types of MCs; therefore, various techniques are often combined to yield reliable results. Biosensor development offered a problem-solving approach in the detection of MCs due to their high accuracy, sensitivity, rapid response, and portability. In this review, an endeavor has been made to uncover emerging techniques used for the detection and quantification of the MCs.

Cyanotoxins and Food Contamination in Developing Countries: Review of Their Types, Toxicity, Analysis, Occurrence and Mitigation Strategies

“…Past and current techniques for (semi)quantitative analysis of cyanotoxins are based on two approaches. Chemical analytical methods which include capillary electrophoresis (CE) and liquid chromatography (LC) coupled with ultraviolet detector (UV) or photodiode array detector (PDA) or fluorescence detectors (FLD) or tandem mass spectrometry (MS/MS) [99][100][101] while the biological assays implies mouse bioassays, enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assays (PPIA) [42,65,102]. A general comparison between these techniques is outlined in Table 1.…”

Ganga river water quality assessment using combined approaches: physico-chemical parameters and cyanobacterial toxicity detection with special reference to microcystins and molecular characterization of microcystin synthetase (mcy) genes carrying cyanobacteria

“…Due to the role of algal abundance in determining the water quality in the freshwater ecosystems, cyanobacteria have been accepted as a major bioindicator of water pollution worldwide (Mateo et al 2015;Casero et al 2019). The toxic strains of cyanobacteria such as Microcystis, Planktothrix, Anabaena, Anabaenopsis, Nostoc, Oscillatoria, Aphanocapsa, Hapalosiphon, Fischerella, Gloeotrichia, Nodularia are the known producers of the hepatotoxic microcystins (MCs) (Kumar et al 2020a; Wang et al 2021). MCs are tumor promoter as they inhibit protein phosphatase type 1 and 2A in eukaryotes (Codd et al 2005) and pose a signi cant health threat for drinking, irrigation water supplies and the environment at large (Turner et al 2018; Massey et al 2020).…”

“…Although diverse communities of cyanobacteria are found in the river Ganga water, however, identi cation of toxigenic cyanobacteria that possess mcy genes as well as direct quanti cation of MCs are needed. Number of analytical techniques such as protein phosphatase inhibition assay (PPIA), enzyme-linked immunosorbent assay (ELISA), highperformance liquid chromatography (HPLC), mass spectrometry (MS) has been employed for the monitoring of different MCs in the contaminated water samples (Kumar et al 2020a; Massey et al 2020). Molecular technique such as polymerase chain reaction (PCR) based detection of mcy genes (mcyA, mcyB, mcyD, mcyE and mcyG) is rapid, cost-effective as well as facilitated the culture independent identi cation of toxic cyanobacteria in environmental samples (Genuario et al 2010; Ribeiro et al 2020).…”

“…Pandey et al content was 1.46 mg/L and 1.15 mg/L during June 2017 and March 2018, respectively. The trend of phosphate concentration in the particular region was more or less similar and not much effect of time was observed.Chloride is present naturally in all water types; however, its major contribution is the runoff of inorganic fertilizers from agricultural land and sewage discharge(Lkr et al 2020). The chloride concentration variation was 65 mg/L (at site 2 and 7) to 104 mg/L (at site 7) in two different times for two years (June 2017 and March 2018).…”

Investigation of the Occurrence of Cyanotoxins in Lake Karaoun (Lebanon) by Mass Spectrometry, Bioassays and Molecular Methods

“…In particular, the shortcomings of ELISA are its high susceptibility to matrix effects, the variable cross-reactivity of different MC congeners and the response to degradation and/or transformation products of MCs that can result in overestimations [ 26 ]. In addition, PPIA based on the assessment of enzyme activity indicating the overall toxicity, does not have the same sensitivity to the different MCs and may also interfere with other unknown compounds present in the sample, thus resulting in under- or over-estimation of the concentration of toxins [ 27 ]. Furthermore, ELISA/PPIA lack the specificity of LC-MS/MS, as they respond to structurally/functionally similar molecules in total, and not to specific MC congeners.…”