INFLUENCE OF INTRACELLULAR PH ON LIGHT-EMISSION FROM A LUXA B DERIVATIVE OF LACTOCOCCUS-LACTIS SUBSP DIACETYLACTIS/

High levels of constitutive aldehyde-dependent light emission were obt ained from non-growing cells of Lactococcus lactis subsp. diacetylacti s F712 transformed with luxA/B when they were suspended in buffered so lutions. Inductions of light emission was time-dependent and was not d ue to growth, synthesis of luciferase or stimulation of metabolism by fermentable carbohydrate. The major factor controlling light emission in such cells appears to be the intracellular pH value. Experiments wi th ionophores indicated that a transmembrane pH gradient was not essen tial for light emission.