Endogenous rhythmicity and energy transduction

Abstract

1. All enzymes tested: malate dehydrogenase (MDH), glutamate dehydrogenase (GDH), glucose-6-phosphate dehydrogenase (G-6-PDH), and 6-phosphogluconate dehydrogenase (6-P-GDH)_behaved rhythmically during a period of continuous white light interrupted by darkness. All showed approximately the same frequency of 12-15 h. 2. The enzymes of the tricarboxylic-acid cycle (MDH and GDH) are in phase with each other but are out of phase with those of the oxidative pentose-phosphate pathway (G-6-PDH and 6-P-GDH) which are in turn in phase with each other. 3. GDH appears to be activated by the addition of Hoagland's solution which leads to an overt rhythm 24 h prior to darkness. The rhythms of MDH, G-6-PDH and 6-P-GDH cannot be demonstrated prior to the onset of darkness due to an inhibition of the MDH and pentose-phosphate cycle enzymes by light. 4. The control of the frequency and phase of these rhythms are discussed in relation to a positive correlation of the rhythms in enzyme activity presented here and the rhythms of the pyridine nucleotides presented elsewhere.

EFFECT OF LIGHT ON OSCILLATIONS OF ENZYME ACTIVITY DURING PHOTOMORPHOGENESIS IN CHENOPODIUM RUBRUM L.

“…O n e of the problems encountered when the data were compiled was the presence of an oscillation with a frequency which was higher than either circadian or the 12-15 h periods found previously (Deitzer et a[., 1974a;. For purposes of illustration the analysis of the raw data for the NADP-GPD is presented in Fig.…”

“…Samples were removed either every 1.5 h for 3 days following germination or every 0.5 h for a 24 h period between 24 and 48 h after germination and immediately frozen in liquid N2. The extraction procedures are the same as those described by Deitzer et al (1974a).…”

“…The details for the assay procedures are reported in for ( I ) and (2). Deitzer et al (1974a) for (3), (4), (6) and (7) and Deitzer er nl. (1974b) for (5).…”

“…Endogenous oscillations of enzyme activity for all pathways considered were found to be in the range of 12-15 h (Deitzer et al, 1974a;. Phytochrome was shown to interact with the Calvin cycle enzyme, (NADP) glyceraldehyde-3-phosphate dehydrogenase (NADP-GPD) and adenylate kinase (AK) but not with any of the other enzymes tested.…”

The Determination of Periodicities in Short‐term Time‐series Data in the Presence of High Frequency Noise and Long‐term Trend

“…Samples of 50 seedlings each were taken at 1.5 h intervals and immediately frozen in liquid N1. ground and extracted as previously described (Deitzer et al, 1974). The activity of the (NADP) glyceraldehyde-3-phosphate de-hydrogenase (NADP-GPD, E.C.…”