FRANK H. JOHNSON 285 



level before applying pressure, according to whether the temperature 

 is below, near, or above the normal optimum temperature of the 

 system, and (5) the steady-state level of luminescence intensity after 

 releasing pressure is the same as the steady-state level before apply- 



250 



34' 



6000 psi ON < 

 6000 psi OFF \ 



I I I 



Fig. 12. Influence of pressure at different temperatures on the luminescence of 

 cell-free extracts of A. fischeri with added DPNH2, FMN, and decaldehyde 

 (saturated system). Arrows pointing upwards indicate the time when pres- 

 sure was applied; arrows pointing downwards, when it was released. The 

 cur\es for rising intensity after release of pressure (except the curve for 

 34° C) have been arbitrarily displaced to the right on the abscissa, to avoid 

 intersecting hnes. The intensity at normal pressure, just before raising the 

 pressure, is arbitrarily taken equal to 100 at each temperature, and all other 

 points computed relatiNe to this value. Allowance was made for the amount 

 of decay when it was significant during the periods involved, as at the 

 higher temperatures. The increased pressure was 6000 psi at each tempera- 

 ture except 3° C where it was 6500 psi. Data obtained with intact cells of 

 A. fischeri at 16° C are included for purposes of comparison. (After Strehler 

 and Johnson, 1954.) 



