Lighting The Way

USING CURRENT TECHNIQUES, DOCTORS MUST WAIT up to 18 weeks for laboratory . results to identify which drugs effectively treat strains of tuberculosis. Now scientists have come up with an ingenious assay that promises to cut that time in half -- literally by shedding a new light on TB. Their bright new idea comes from the same gene that makes fireflies glow.

In a report to Science, researchers at the Albert Einstein College of Medicine say they insert the gene, which directs production of a light- emitting enzyme called luciferase, into tissue samples taken from TB patients. Within two hours, the cultures are aglow. Various drugs are then introduced. If the particular strain of TB is susceptible, the light dims and goes out. If the TB is resistant, the culture keeps shining.