Investigations of microcystins (cyanobacterial peptide toxins) detection, purification and analysis.

Coyle, Sadie Maria

Abstract

Cyanobacteria (blue-green algae) occur commonly in British freshwaters sometimes producing extensive growths known as water blooms. This study was an investigation of microcystins, the cyclic heptapeptide toxins produced by cyanobacteria. The method of detection relied on high performance liquid chromatography (HPLC) analysis which led to the development of large-scale purification processes to provide material for use as standards in routine monitoring of natural waters and laboratory cultures. These methods were also employed to purify unknown microcystin variants for characterisation. The purified variants were used to constuct a spectral library, using a photodiode array detector, against which samples were screened and any microcystins present identified and quantified. The above detection method was used to monitor the occurrence of several microcystins present in loch water during a single day. This study observed considerable spatial and temporal variation in the occurrence of these microcystins but suggests how sampling techniques may help reduce this variability. Ecological studies, such as that above, require a large number of samples. This led to the development of a simple and rapid sampling and extraction method for microcystins. It was specifically designed for suspensions of cells in open water and enabled rapid sample processing prior to analysis by HPLC. This method was also used in the development of a 14 day bioassay to investigate environmental factors influencing the growth and toxin content of cyanobacteria. Once optimised the bioassay method was used to try and identify parameters limiting growth and toxin production in a selected freshwater loch.

Citation

COYLE, S.M. 1997. Investigations of microcystins (cyanobacterial peptide toxins) detection, purification and analysis. Robert Gordon University, PhD thesis. Hosted on OpenAIR [online]. Available from: https://doi.org/10.48526/rgu-wt-2807335

• Thesis Type: Thesis
• Deposit Date: Jun 27, 2025
• Publicly Available Date: Jun 27, 2025
• DOI: https://doi.org/10.48526/rgu-wt-2807335
• Public URL: https://rgu-repository.worktribe.com/output/2807335
• Award Date: May 31, 1997