The Science Behind BlueGreenTest

Future Toxin Testing

Although not as widespread, other toxins including alkaloids and endotoxins are still prevalent globally and require special attention as they induce varied physiological and ecological responses. For example, in a study of tropical Australia the species Cylindrospermopsis raciborskii accounted for 87.5% of total blooms ⁽⁴⁸⁾, whose various strains can produce the alkaloid toxins; cylindrospermopsis, anatoxin-a, and saxitoxin ⁽⁴⁹⁾.

The main toxin-producing genera and primary organs impacted are outlined in the table below, and will be targeted in the development of future cyanotoxin testing.

Molecular Testing for Cyanotoxins

Traditionally, cyanobacteria monitoring has been based on microscopic counting and identification of single organisms. However, complex bioanalytical molecular testing is necessary in order to detect and quantify potentially toxic cyanobacterial species or strains, as cyanotoxin and non-cyanotoxin producing strains of the same species cannot be discriminated under the microscope.

The largest challenge facing analysing cyanotoxin levels is the highly variable nature of toxicity, in conjunction with the undefined number of chemical species displayed in each group of toxins. In particular,the majority of current testing techniques require a significant amount of time to process before results can be analysed. However, this is problematic due to the highly time-dependent nature of cyanotoxic hazards, particularly in remote sampling areas involving drinking water units ⁽⁵⁰⁾.

There are numerous analytical methods used in the detection of MCs/Nod, including:

Each method provides different and often complementary information which can be used in conjunction with another to provide a detailed insight into the toxicological profile of the sample. The type of method employed will largely be determined by the type of data required, including the time frame and sensitivity ⁽⁹⁾

Mass spectrometry identifies chemicals present within a sample by ionizing substances and then sorting the ions based on a ratio of their mass and ionic charge. In particular, high-resolution mass-spectrometry provides a fairly reliable technique to identify cyanotoxins, as long at the toxin level is significantly high enough. However, quantitation in this method is difficult due to the lack of isotopically labelled standards for dilutions techniques ⁽⁵¹⁾

Enzyme-based protein phosphatase inhibition assays targets the protein-inhibiting properties of cyanotoxins and records the rate of these select compounds over time within a sample. PPIAs are a robust tool, and are especially useful in diagnostic testing as they have the potential to detect the presence of toxins which may escape detection in other tests ⁽⁵²⁾

High performance liquid chromatography (HPLC) uses a separation process to isolate individual components of a mixture and determine the quantities of each present. This method can be performed mass spectrometry to increase the sensitivity and accuracy of the final results ⁽⁵³⁾.

The BlueGreenTest ® utilises immunoassay techniques, explained on the next page.

References

The Basic of Immunoassay's