Phage ​Technology ​Detects ​Contaminated ​Water Faster ​Than Standard ​Tests

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Phage ​Technology ​Detects ​Contaminated ​Water Faster ​Than Standard ​Tests

A team of researchers at Cornell University, Iowa State University, and the organization Global Good/Intellectual Ventures has developed a sensitive, bacteriophage-based technique to detect one particular E. coli strain in water in less than half a day.

Study coauthor Sam Nugen of Cornell presented the work during a talk in the Division of Agricultural and Food Chemistry at the American Chemical Society national meeting in Boston.

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Found in great numbers all over our bodies, bacteriophage viruses are harmless to humans yet lethal to bacteria, Nugen said. Bacteriophages prey on bacteria by hijacking the bacteria’s internal machinery to express the phage’s own DNA and then forcing them to self-destruct.

To adapt phages’ bacteria-killing abilities for bacteria detection, the researchers inserted the gene for a reporter enzyme into a bacteriophage called T7NLC. The reporter enzyme, a luciferase known as NanoLuc, glows when expressed by bacterial cells, thus detecting E. coli. Fused to the enzyme is a module that binds to cellulose to provide a way to collect the enzymes for analysis.

When researchers added the engineered bacteriophages to E. coli contaminated water along with insoluble cellulose pellets, the phages infected the bacterial cells. After the bacteria expressed the luminescent reporter enzyme, the cells disintegrated, freeing the enzyme, which clung to the cellulose pellets. Decanting off the water quickly concentrated samples. Using a laboratory plate counter or normal camera set to 30-second exposure time, scientists quantitatively measured the presence of under 10 colony forming units of E. coli per 100 mL within three hours.

Read full article: Chemical & Engineering News

Reference Paper:  Reporter bacteriophage T7NLC utilizes a novel NanoLuc::CBM fusion for the ultrasensitive detection of Escherichia coli in water

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