These results also must reflect the exposure to continuous light
for EL cells that likely leads to loss or impairment of the circadian
clock in C. reinhardtii that is reset by blue/green and red light [42–
44]. To test this idea, we searched for significant gene expression
differences among a number of clock-related genes in this alga
[42]. These included RHYTHM OF CHLOROPLAST (ROC)
genes [43], cryptochromes (CPH1), phototropins, phytochromes,
and casein kinases (CK1, CK2B). Clock-related genes that showed
significant down-regulation were CPH1 that encodes a cryptochrome
related to DNA photolyases that act as photoreceptors
degraded in light [45]. A serine/threonine-kinase domain