Following on from the publication of our interlaboratory performance and accuracy paper the Standard Methods Committee (SMC) and Joint Task Groups (JTGs) of Standard Methods, the mutual publication of the American Public Health Association (APHA), American Water Works Association (AWWA), and the Water Environment Federation (WEF) have approved and now published the CyanoDTec assay as Standard Method 10120; QUANTITATIVE PCR FOR CYANOBACTERIA AND CYANOTOXIN-PRODUCING GENES.
READ THE PAPER HERE: https://www.standardmethods.org/doi/abs/10.2105/SMWW.2882.266
Abstract: 10120 A:2025 INTRODUCTION TO DETECTING CYANOBACTERIA AND TOXINS WITH qPCR
Quantitative polymerase chain reaction (qPCR or real-time PCR) is a molecular technique used for amplifying and detecting specific DNA molecules. In qPCR, the accumulation and amplification of DNA molecules are measured as the reaction progresses in a thermal cycler. DNA amplification is detected by fluorescence emitted from DNA-binding fluorescent dyes or fluorescently labelled specific oligonucleotides. Fluorescence measurements are proportional to the total amount of molecules produced and are used to calculate the initial amount of DNA molecules present in the reaction. qPCR reactions are highly sensitive over a wide dynamic range of DNA concentrations.
Significant efforts have been made to establish guidelines and protocols for qPCR assay development and validation.1 As a result, qPCR has been adopted for the microbial risk assessment of drinking water.2,3,4 Unlike microbiological culture methods that may take days to produce results, samples for qPCR can be prepared and analyzed in a few hours.5 For example, several environmental samples can be tested for cyanobacteria in a single run of qPCR assays. The savings in time includes the expertise, physical resources, and classification efforts required for the microscopic identification and quantification of the samples’ nontoxic and toxic cyanobacteria species.
Phytoxigene CyanoDTec is a molecular assay for cyanobacteria and toxin-producing genes based on qPCR. Other assays that meet the performance criteria in this method are considered equivalent and may also be used. The assay designed for aquatic environmental samples detects and quantifies the presence of cyanobacteria and their genes encoding toxin-production.6,7 Not all cyanobacteria species produce toxins; therefore, the presence of cyanobacteria does not immediately indicate the presence of toxins. With a high degree of reproducibility, this qPCR test quantifies both the amount of overall cyanobacteria present in a sample along with the number of genes that are responsible for the production of certain toxins.8 Toxins associated with cyanobacteria can be hepatotoxins or neurotoxins. The hepatotoxins include microcystin, nodularin, and cylindrospermopsin, while saxitoxin, anatoxin, and guanitoxin are the primary neurotoxins produced by cyanobacteria.
Abstract: Citation
Standard Methods Committee of the American Public Health Association, American Water Works Association, Water Environment Federation. Baxter TE, Lipps WC, eds. Assessment of Aquatic Biology: 10120 Quantitative PCR of Cyanobacteria and Cyanotoxin-Producing Genes. Standard Methods for the Examination of Water and Wastewater. 25th edition. APHA Press, 2028, p. x-x.