296 



LIGHT AND LIFE 



A Gonyaidax cell is about 40 microns in diameter and emits bright 

 flashes of light which last for less than one-tenth of a second (4, 5) . 

 This flashing occurs when the cell is agitated or stimulated. The 

 IDrocess of harvesting in itself, therefore, causes a large quantity of 

 light to be emitted, meaning that a considerable amount of luciferin 

 has been utilized and presumably lost. Chemical agents also stimulate 

 flashing, and attempts to block luminescence during harvesting by 



.04 



in 



z 



i .02- 



r^ 



CRUDE 

 EXTRACT 



L£ 



^: .1 ml SATURATED AMMONIUM 

 SULFATE ADDED 



BUFFER 



2 



6 



8 



TIME - MINUTES 



Fig. 2. 1 his illustrates the effect of added salt on tlic limiinescence of a cell- 

 free extract. .\t zero time 0.1 ml of a crude extract was added to 0.7 ml of water. 

 This was followed at the times indicated by 0.,') ml of 0.1 M Tris-maleate-NaOH buf- 

 fer, and 0.1 ml quantities of saturated ammonium sulfate. 



adding inhibitors have resulted only in stimulation of this sort, A 

 photograph of the luminescence of Gonyaulax taken with its own 

 light emission is shown in Fig. 1. 



A cell-free cold water extract of Gonyaulax cells contains both the 

 luciferin and the luciferase, but does not emit light unless salt is added 

 (Fig. 2) . A variety of salts are effective in stimulating light emis- 

 sion, and for each of them a relatively high concentration is required 

 for optinuun activity of the luminescent system (see below) . 



