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Laboratory analysis of cyanobacterial toxins and bioassays
Published in Ingrid Chorus, Martin Welker, Toxic Cyanobacteria in Water, 2021
Linda A. Lawton, James S. Metcalf, Bojana Žegura, Ralf Junek, Martin Welker, Andrea Törökné, Luděk Bláha
The analysis of saxitoxins has been fraught with many difficulties as saxitoxins do not contain a chromophore (do not adsorb light) nor natural fluorescence; hence, typical HPLC detectors cannot be used to identify or quantify them. Further, they are very polar molecules that are not easily retained by reverse-phase chromatography (e.g., using C18 columns). Derivatisation to form a fluorescent analyte has proven valuable, with both precolumn and postcolumn (i.e., the saxitoxins are first chromatographically separated and then mixed with the derivatisation reagents before detection) methods developed and the precolumn method becoming an AOAC Official Method (AOAC, 2005b; 2011). While this method is validated for the analysis of paralytic shellfish poisoning in shellfish, it is also suitable for the analysis of saxitoxins from cyanobacteria in cells, water and tissues.
Detection of Food, Agricultural and Aquatic Contaminants
Published in Richard O’Kennedy, Caroline Murphy, Immunoassays, 2017
Marie Le Berre, Caroline Viguier, Caroline Murphy, Niamh Gilmartinb
Although predominately considered a marine toxin, saxitoxin can also be produced by cyanobacteria in fresh water. The multiplex detection of freshwater toxins microcystin, saxitoxin and other major cyanotoxins, was demonstrated by Zhang et al. [111]. In less than 25 minutes, multiple samples for these three cyanotoxins could be analysed in a simple microfluidic chip that has the potential to be fully automated. Similarly, a novel multiplex microarray was developed for the detection of five toxins: domoic acid (DA), okadaic acid (OA, and analogues), saxitoxin (STX, and analogues), cylindrospermopsin (CYN) and microcystins (MC, and analogues) [112]. Detection limits for the 15 min assay were 0.37, 0.44, 0.05, 0.08, and 0.40 ng mL−1 for DA, OA, STX, CYN, and MC, respectively. Due to the rapid, easy-to-use and highly sensitive features of this assay it could potentially be used as a screening tool for the aforementioned toxins in water.
New Trends in Biosensors for Food and Water Safety Monitoring
Published in Sibel A. Ozkan, Bengi Uslu, Mustafa Kemal Sezgintürk, Biosensors, 2023
Maroua Hamami, Sondes Ben Aissa, Noureddine Raouafi
Among marine biotoxins, saxitoxin (STX) is one of the major toxins of paralytic shell-fish poison and can cause shock, asphyxia and even death to fisheries and humans. Qi et al. developed a facile label-free electrochemical aptasensor assembled with nanotetrahedron and DNA triplex for the sensitive detection of STX (Figure 8.7) (49). The innovative combination between aptamer, DNA triplex and DNA nanotetrahedron scaffold was advantageous to assist the aptamer orientation and protect it from adsorption to the surface of screen-printed electrodes, allowing its full accessibility to STX. The aptasensor showed high sensitivity with a LOD of 0.92 nM and demonstrated good applicability to detect STX in seawater samples, with a recovery ranging from 94.4% to 111%.
A review of algal toxin exposures on reserved federal lands and among trust species in the United States
Published in Critical Reviews in Environmental Science and Technology, 2022
Zachary R. Laughrey, Victoria G. Christensen, Robert J. Dusek, Sarena Senegal, Julia S. Lankton, Tracy A. Ziegler, Lee C. Jones, Daniel K. Jones, Brianna M. Williams, Stephanie Gordon, Gerald A. Clyde, Erich B. Emery, Keith A. Loftin
Saxitoxins are neurotoxins produced by several species of freshwater cyanobacteria and marine algae (Supplemental Table 1). Saxitoxin acts as a sodium channel blocker that can affect gastrointestinal, neurological, and neuromuscular function that may lead to respiratory paralysis and death (Christensen & Khan, 2020; Cusick & Sayler, 2013). Saxitoxin producing organisms have been found along the Atlantic, Pacific, and Gulf coasts of the United States. Saxitoxin exposure has been documented in 22 Trust species including: 12 species of marine mammals, 8 species of birds, and 1 reptile and 1 fish species (Supplementary Tables 8 and 9) in 5 states (Supplementary Table 10 and Figure 2). Exposure to saxitoxins is primarily by consumption of contaminated prey species (Deeds et al., 2008).