NITRATE REDUCTASE—A KEY ENZYME IN BLUE LIGHT-PROMOTED CONIDIATION AND ABSORBANCE CHANGE OF NEUROSPORA

1979 ◽  
Vol 29 (3) ◽  
pp. 629-632 ◽  
Author(s):  
Eva Klemm ◽  
Helga Ninnemann
2006 ◽  
Vol 33 (7) ◽  
pp. 697 ◽  
Author(s):  
Wang Chang-Quan ◽  
Liu Tao

Seeds of the halophyte Suaeda salsa (L.) Pall. were cultured in 24 h dark and 14 h blue light / 10 h dark to examine the role of blue light and the blue-light-absorbing photoreceptor cryptochrome 2 (CRY2) in betacyanin accumulation, hypocotyl elongation and cotyledon opening in S. salsa seedlings. Darkness significantly promoted betacyanin accumulation and hypocotyl elongation but inhibited cotyledon opening. Blue light suppressed betacyanin accumulation and hypocotyl elongation but stimulated cotyledon opening. Betacyanin in S. salsa seedlings decomposed with time in blue light. Western blot analysis showed that CRY2 protein accumulated both in hypocotyls and cotyledons of S. salsa seedlings grown in dark, but degraded with time in blue light, which was paralleled by a decrease of tyrosine hydroxylation activity of tyrosinase, a key enzyme involved in the betalain biosynthesis pathway. These results suggest that CRY2 protein mediates betacyanin decomposition via inactivation of tyrosinase in S. salsa seedlings, and the blue-light-dependent degradation of CRY2 protein is crucial to its function.


2020 ◽  
Vol 532 (4) ◽  
pp. 633-639
Author(s):  
Yu-Fan Fu ◽  
Zhong-Wei Zhang ◽  
Xin-Yue Yang ◽  
Chang-Quan Wang ◽  
Ting Lan ◽  
...  

1974 ◽  
Vol 52 (6) ◽  
pp. 1433-1435 ◽  
Author(s):  
R. W. Jones ◽  
R. W. Sheard

Under conditions in which the light requirement for phytochrome mediation was inferred to be above saturation, white and blue lights enhanced the extractable nitrate reductase activity of etiolated pea terminal buds above the levels engendered by red and far-red lights. The regulation of nitrate reductase by light in the terminal buds appears to involve both phytochrome and a blue-sensitive high-energy reaction.


1976 ◽  
Vol 70 (4) ◽  
pp. 1071-1077 ◽  
Author(s):  
Pedro J. Aparicio ◽  
JoséM. Roldán ◽  
Fernando Calero

1992 ◽  
Vol 19 (6) ◽  
pp. 625 ◽  
Author(s):  
A Corzo ◽  
X Niell

The regulation by light (especially blue light) and NO3- of the nitrate reductase (NR) activity was studied in the marine green macroalga Ulva rigida C. Agardh. NR activity was measured in situ as no available in vitro method exists for Ulva rigida. The effectiveness spectrum of NR-enhancement by light was determined. Blue light was clearly the most effective wavelength, being more effective than white or red light. Blue light enhancement of NR was strictly dependent on photosynthesis since it was inhibited by 95% in presence of 5 × 10-5 M DCMU. The time course of NR enhancement by blue light was hyperbolic in shape, the semimaximal level of increase was reached in 24 min in N-sufficient algae. Blue light activation of NR is dependent upon photo flux density in a sigmoidal manner; 95% of the maximum increase was reached at 137 μmol m-2 s-1. Blue light enhancement of NR is linearly dependent on the amount of KNO3 available in the medium at the beginning of the experiment. Increase in NO3- by itself, in dark or without a concomitant increase in photon flux density, only increases NR activity by 12% (darkness) or 25% (white light, 4 μmol m-2 s-1) with respect to a blue light control. The blue light enhancement of NR was inhibited by actinomycin D (33%), rifampicin (32%) and cycloheximide (88%). Therefore, in Ulva rigida the blue light enhancement of NR occurs mainly by induction of de novo synthesis.


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