R. L. A HUH 269 



niokl biohmiiiiescent reaction did tiot result in loss of the albnmin 

 ctted. Also, neither a-tocoj^herol, a-tocopherol acetate, nor menadione 

 were fomul to stimulate light emission. Addition of antimycin A, 

 at a final concentration of 5 micrograms per milliliter, had no effect 

 on a reaction run in the jjresence of albumin. Dialysis of the bovine 

 plasma aliiinnin at pH 7.0, previous to use, had no effect on its 

 stinudatory activity. Indeed, if the light reaction is carried out with 

 the albumin contained in dialyzing tubing, there is no stimulation. 

 The actual function of the bovine albumin is unknown. Similar 

 stimulatory effects have been found in other systems upon addition of 

 amino acids, chelating agents, calcium phosphate gel, or protein 



(2, 3, 4, 7) . Such effects could be, and have been variously ascribed 

 to (a) adsorption of an inhibitor, (b) non-specific effects on the 

 steric relationship of the reactants, or (c) addition of a component 

 other than protein acting as the stimulating agent. 



As noted, both the bioluminescent systems of the bacteria and 

 firefly have presented the i^roblem of luciferase inhibition during 

 the initial stages of isolation. McElroy et al. (8) found, during the 

 purification of the bacterial system, two effects of irradiating various 

 enzyme fractions with idtraviolet light: (1) photo-destruction of 

 an inhibitor — presumably flavin mononucleotide (FMN) , and (2) 

 production of an essential factor in the 20-30% (NH4)2S04 enzyme 

 fraction. In view of these results, work was initiated concerning the 

 response of the luminous fungi to ultraviolet light. 



In Fig. 5, the response of a slant of the luminous mold Armillaria 

 mellea to ultraviolet light (Black Ray 3660A Lamp) is presented. 

 This experiment was carried out wdth the slants in a 22°C water 

 bath and with adequate controls to assure that the effects measured 

 were light, and not thermal, effects. During exposure the lumines- 

 cence decreased markedly. When the ultraviolet light source was 

 removed, there was a rapid increase in light emission, finally reach- 

 ing a value approximately 70 per cent greater than the original steady 

 state. The residts suggest that there may be present in the luminous 

 system in vivo: (a) a photo-labile component which is essential for 

 light emission; and (b) a component, also photo-labile, that nor- 

 mally inhibits the emission of light from this organism. A similar 

 experiment was carried out in which both the hot water extract 



(luciferin) and a 0-75% (NH4) 2SO4 enzyme preparation were ex- 

 posed to ultraviolet light for varying periods of time. The solutions 

 were irradiated at 5^C. In the dark controls, the enzyme and the 

 hot water extract were placed in separate beakers that had been 



