Current Techniques for Detecting and Monitoring Algal Toxins and Causative Harmful Algal Blooms

Abstract

The detection and monitoring techniques for algal toxins and the causative harmful algal blooms (HABs) are essential for the protection of aquatic lives, shellfish safety, drinking water quality, and public health. Toward the development of fast, easy, and reliable techniques, much progress has been made during the last decade for the qualitative and quantitative analysis of algal toxins. This review highlights the recent progress and new trends of these analytical and monitoring tools, ranging from in-situ quick screening protocols for the monitoring of algal blooms to mass spectrometric analysis of trace levels of various algal toxins and structural elucidation. Solid-phase adsorption toxin tracking (SPATT) deployed in the field for the passive sampling of algal toxins has been recently validated, and improved ELISA-based methods with lower detection limits for more toxins have become commercially available for both screening and routine monitoring purposes. Liquid chromatography-mass spectrometry with several recent mass spectrometric innovations has expanded our understanding of traditional toxins, their metabolites along with newly discovered toxins of ecological importance. Several established in vivo and in vitro bioassays will continue to be used as benchmark toxicological testing of algal toxins; however, newly emerged molecular probing techniques such as real-time quantitative polymerase chain reaction (qPCR) have extended our ability to trace algal toxins from causative organisms at the molecular level. New chemical and biological sensors, lab-on-chip and remote sensing of blooms being developed will hold promise for early warning and routine monitoring to better manage and protect our freshwater, coastal and marine resources from adverse impact by harmful algal blooms.

Foodomics for investigations of food toxins

“…Further on, immunological testing by use of A c c e p t e d M a n u s c r i p t 9 commercially developed kits is a method of choice only for detection of bacterial toxin effects (antibody production) in the host organism. For example, ELISA double antibody sandwich and automated enzyme-linked fluorescent immunoassay (ELFA) are used for detection and semiquantification of Staphylococus, Clostridium exotoxins and cyanotoxin microcystin [24,27]. Although, immunological assays are officially approved they lack specificity and sensitivity and produce false positives and false negatives signal due to cross-reactions.…”

“…In the last decade rapid and sensitive screening methods for monitoring of food toxins were introduced: bioassays, molecular biology and/or immunological techniques, gel-clot technique, turbidimetric technique, biosensors and chromatographic as well as mass spectrometry-based methods [7,[22][23][24]. Bioassays are used when fast analysis of potentially contaminated food is required [25] and/or for assessment of cytotoxic action of food toxin in cell cultures.…”

Advances in Technological Research for Online and In Situ Water Quality Monitoring—A Review

“…The determination of algae and cyanobacteria in water can be conducted through numerous techniques, such as cell counting with the aid of an optical microscope or the analysis of indicator substances, such as chlorophylls [143]. Chlorophyll analysis is widespread because it is an active optical pigment capable of being determined by spectrophotometry, fluorimetry, and High-Performance Liquid Chromatography (HPLC) [35,144]. In addition, the analysis of such organisms can also be done remotely by observing different bands of satellite images [144] and by means of cytometry [145], which allows counting the number of cells.…”

“…Chlorophyll analysis is widespread because it is an active optical pigment capable of being determined by spectrophotometry, fluorimetry, and High-Performance Liquid Chromatography (HPLC) [35,144]. In addition, the analysis of such organisms can also be done remotely by observing different bands of satellite images [144] and by means of cytometry [145], which allows counting the number of cells. The following works present the development of new technologies for Algae and Cyanobacteria in water quality monitoring, as also summarized in Table 12.…”