Firefly power lights up labs

THE GLOW of fireflies is lighting the path for a Cambridge biotechnology company to develop a new way of detecting and identifying bacteria. It will replace the 110-year-old method of taking samples and seeing if they grow.

The old technique of growing bacteria in dishes containing a nutrient-rich medium - Agar plates - until they can be identified visually, takes two to seven days. Celsis International says its method is much more sensitive and takes around eight hours. In the Celsis system, bacteria are detected by recording the light- emitting reaction when luciferase - the enzyme causing fireflies to glow - reacts with molecules in the bacteria.

Cutting the time taken to test for bacteria will produce cost savings in a variety of industries that are subject to stringent quality control and hygiene standards. In the pharmaceutical industry, for example, drugs have to be tested for contamination before they leave the factory. This may mean expensive products being stockpiled for up to a week.

According to Tony Martin, chief executive of Celsis, the pharmaceutical industry worldwide holds up to dollars 1bn ( pounds 660m) of inventory at any time, awaiting the results of contamination testing. In the cosmetics industry, bacteria in shampoos and creams can produce enough carbon dioxide to make the container explode.

Independent research commissioned by Celsis indicates that in the UK alone, more than 100 million tests for microbial contamination are carried out each year, with production lines on hold and goods stockpiled while the results come through. 'There is no doubt that there is a growing worldwide demand for faster methods of measuring and identifying microbial contaminants,' Dr Martin said. 'This is driven by regulatory controls, environmental concerns and economic pressure.'

The mechanism of bioluminescence was discovered 30 years ago, and it has been applied in other tests such as diagnosing thyroid disease and testing new types of tuberculosis drugs. The gene that produces luciferase has been identified, and suggested applications include inserting the gene into plants, making them glow in the dark to save on street lighting.

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