BIOCHEMICAL CHARACTERISTICS OF ALDEHYDE AND LUCIFERASE MUTANTS OF LUMINOUS BACTERIA

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Abstract
A culture of Achromobacter fischeri was exposed to UV and biochemical mutant colonies separated by replica plating. Non- luminous or dark" mutants, detected by observing individual colonies in the dark, grow equally well on complete and minimal media. The photomultiplier apparatus shows that 2 of the dark mutants have a low but measurable luminescence from living cells, which can be stimulated to light emission within 5 seconds by adding saturated aqueous dodecyl aldehyde to a suspension of the mutants. Five other dark mutants are not stimulated to luminescence by any known factor. Both cell-free extracts and intact cells of dark mutants are stimulated by a variety of long-chain aldehydes; the time for light emission apparently depends on rate of penetration of the aldehyde. Dark mutants which emit light immediately upon addition of an aldehyde have a higher lucif-erase content. Mutants which did not yield light in the presence of aldehyde, diphosphopyridine and riboflavin phosphate may be blocked in the synthesis of flavoprotein luciferase. It is suggested that light emission in luminous bacteria is controlled by at least 2 genetic factors which do not affect growth.