Harmful algal Blooms (HABs) develop when algal colonies grow out of control, causing toxicity or injury to humans, fish, shellfish, marine mammals, and birds. Most HABs of public health concern in saltwater generally are caused by eukaryotic dinoflagellates and diatoms. Prokaryotic cyanobacteria are usually responsible for freshwater blooms although they can contribute to saltwater and brackish blooms too. A common monitoring target of both groups is the saxitoxin-encoding genes. Saxitoxin(STX) is responsible for Paralytic shellfish poisoning, a foodborne illness developed from consumption of STX contaminated shellfish. Each cyanobacterial SXT gene cluster contains a set of core genes, common to all SXT clusters and a set of genes that vary between different clusters. In cyanobacteria, SxtA seems to be the only gene that initiates STX production and has been focused on in this study. Currently, most widely used monitoring methods require samples to be collected using specific or generalist sampling devices, then sorted and taxonomically identified individually, usually under the microscope, to derive biodiversity information from conventional morphological analysis. Molecular approaches are becoming increasingly popular as tools for measuring biodiversity and environmental management are improving. Targeted detection technologies, primarily based on PCR but increasingly incorporating novel probe-based methodologies, have ushered in a new era in rare species monitoring, such as ballast water surveillance. We hypothesized that there would be enough conserved yet divergent areas in the Saxitoxin gene cluster that can be accessed to create species specific probes that can detect only certain toxic species of concern in HABs. Through multiple sequence alignment, primer designing tools, and other bioinformatic analyses we focused on sxtA gene and identified a potential candidate region. This region now needs to be further studied in wet lab setting and real-world system and has the potential to be developed into a species-specific probe for early detection of HABs.
Ehsan, Shafqat F., "Identifying Molecular Markers for Early Detection of Toxic Cyanobacteria and Dinoflagellate" (2022). St. Mary's University Honors Theses and Projects. 13.
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