Science

Toxic algal bloom test takes the guesswork out of water monitoring
People and health
Summary
Understanding the mechanisms of toxin synthesis has enabled UNSW researchers to create an innovative molecular test that can predict the likelihood of algal blooms with global implications for human and ecological health.
"The test has taken much of the guesswork out of water quality monitoring and significantly reduced costs to managers and end users."

Breakthrough research to understand the mechanisms of toxin synthesis has enabled UNSW researchers to develop and successfully commercialise a molecular test that can predict the likelihood of algal blooms and indicate strategies for their prevention. 

This innovative test has been widely used by water authorities in Australia and countries including the USA, Taiwan, The Netherlands, Canada and Ireland in projects that seek to minimise damage to, and restore and remediate, soil and water in urban catchments and marine systems. 

Aquatic cyanobacteria, otherwise known as blue-green algae, are a group of photosynthetic bacteria that live in a wide variety of moist environments. They are known for their extensive, highly-visible algal blooms that release several different toxins into the water. 

It has long been recognised that the early detection of toxic cyanobacteria is critical as high concentrations of toxins pose a threat to human health, marine life and the ecology of surrounding waterways. Consumption of cyanotoxins can have serious health implications and can even be fatal in high doses. 

Major outbreaks can lead to cities cutting off the water supply, closing recreational waters and restricting commercial fisheries. For example, in the city of Toledo in the State of Ohio in 2014, more than 400,000 people were left without drinking water due to a large cyanobacterial bloom in Lake Erie. Stores sold out of bottled water, local restaurants, universities and public libraries closed and the city was forced to rely on humanitarian aid for the delivery of water.

In the past, management practice has included taking direct measurements of cyanotoxins in water samples using bioassays and chemical analytical methods. However, these are laborious and costly and require specialised chemical standards and equipment. A key limitation of these tests is that they are only applicable once the toxins are present in the water and above a certain detection threshold. 

In contrast, the UNSW team, led by Professor Brett Neilan, a molecular biologist and expert in the study of microbial chemistry and the origins and evolution of life, designed a test that identifies genetic structures specific to toxic bacteria. 

The impetus for this diagnostic test was research that informed the discovery and characterisation of the large gene clusters responsible for the biosynthesis of the most problematic cyanotoxins: microcystin, nodularin, saxitoxin and cylindrospermopsin. The research team was able to translate these discoveries into a molecular method that does not depend on the detection of secreted toxins. Rather, it is able to detect toxigenic cyanobacteria before they produce and release their toxins into the water. 

The novel diagnostic test targets the problematic cyanotoxin gene clusters based on their DNA “footprint”. The commercialised version of the test: Phytoxigene CyanoDTec, developed in collaboration with Diagnostic Technology Australia, is highly specific, sensitive and reproducible due to the inclusion of an internal control. 

The test can be used in the lab and in the field, particularly for the rapid assessment of complex bloom samples. It is designed for high-throughput applications making it ideal for continuous cost-effective monitoring of drinking and recreational water supplies. 

The key benefits of the test are that it has taken much of the guesswork out of water quality monitoring and significantly reduced costs to managers and end users. It has also had a resounding impact on national and international water security. The speed, economy and sensitivity of the methods developed have made it ideal for water quality management.

The discoveries that informed the development of the test were made through a unique collaboration between UNSW Schools of Biotechnology and Biomolecular Sciences, and Civil and Environmental Engineering. This research is a prime example of the successful transfer of laboratory data into a commercialised product with international appeal. 

Partners & Collaborators

•Diagnostic Technology Australia

•UNSW Biotechnology and Biomolecular Sciences

•UNSW Civil and Environmental Engineering

•Sydney Water

•Sydney Catchment Authority 

•Seqwater

•Melbourne Water

•CRC for Water Quality and Treatment 

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