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IDENTIFICATION OF MICROCYSTIN TOXINS FROM A STRAIN OF MICROCYSTIS AERUGINOSA
Citation:
DIEHNELT, C., S. M. PETERMAN, N. DUGAN, AND W. L. BUDDE. IDENTIFICATION OF MICROCYSTIN TOXINS FROM A STRAIN OF MICROCYSTIS AERUGINOSA. Presented at 53rd Annual Conference American Society for Mass Spectrometry, San Antonio, TX, June 07, 2005.
Impact/Purpose:
The purpose of this research project is to develop a strong qualitative and quantitative "gold standard" laboratory reference analytical method for the simultaneous selective and sensitive identification and measurement of those cyanobacteria toxins that are of the highest priority to EPA and state and local drinking water authorities. These toxins are on the drinking water candidate contaminant list (CCL), but the specific toxins that are the most likely to occur, and which are the potentially most hazardous, are not defined on the CCL. Six toxins were recommended for highest consideration by an EPA workshop in May, 2001. These are the alkaloids anatoxin-a and cylindospermopsin, and the four microcystins abbreviated RR, LR, YR , and LA (these characters are the standard single-character designations for four natural aminoacids). There are no published analytical methods that have been demonstrated to have the ability to detect and reliably measure the concentrations of these six compounds in a single drinking or source water sample. The purpose of this research is to not only develop and demonstrate this capability with real environmental samples, but also to do it in a single economical laboratory analytical method that requires about one hour from initial sample preparation to obtaining the results. It is expected that some other toxins will be found in the real environmental samples tested, and perhaps even new toxins may be discovered in this work. The techniques employed in this work, have the capability of tentatively identifying known and unknown toxins even when standards are not available.
Description:
Microcystin toxins are cyclic heptapeptides produced by several genera and species of cyanobacteria that are responsible for the "green scum" frequently observed on eutrophic surface waters. These toxins, which are a million times more toxic than cyanide ion, have caused deaths of farm animals, humans, pets, and wildlife through exposures from drinking and recreational waters. Over 65 microcystin structural variants are known, and all of them contain some standard and some unusual bacterial amino acid residues. The toxins produced by a strain of Microcystis aeruginosa that had not been investigated previously were separated and identified by microbore liquid chromatography (LC)/mass spectrometry (MS), LC/MS/MS, LC/MS/MS/MS, and exact m/z measurements. This research could be considered an example of "environmental proteomics".