Figure 4.
Comparison of Luminescence of MAQ 6.3 Seedlings with Total Apo-Aequorin Activity at Different Times.
(A) Relative apo-aequorin activity during the first hour after the transfer from LL to DD. Seedlings had been in LL for 5 days (22 μE·m−2·s−1) before transfer to darkness. Left ordinate and open squares show in vivo luminescence of seedlings (in relative light units [RLU]); the abscissa shows time after the LL-to-DD transition in minutes.
(B) Apo-aequorin activity of seedlings that had been exposed to different durations of previous light exposure (22 μE·m−2·s−1). Left ordinate and open squares show in vivo luminescence of seedlings integrated for every minute for 90 min; left ordinate and open circles show total apo-aequorin activity of each sample extracted and assayed as for specific apo-aequorin activity (total activity, not normalized to protein concentration); the abscissa shows the duration of light exposure before the LL-to-DD transition; right ordinates and closed symbols show specific activity of apo-aequorin (normalized to protein concentration) extracted at the times indicated from seedlings under the same conditions as in the samples used for luminescence recordings.
Extracted samples (both total and specific) were prepared in triplicate, and apo-aequorin activity was measured in extracts as described in Methods. Error bars indicate standard error of mean. AQ, apo-aequorin; RLU, relative light units.