A circadian rhythm is any biological process that displays an endogenous, entrainable oscillation of about 24 hours.
These 24-hour rhythms are driven by a circadian clock. Circadian rhythms of living animals may be measured by recording their locomotor activity over time, and they are normally entrained by light intensity. Zantiks units can be used to measure the activity of animals, and also control (and change) the lighting regime.
Experimental set up
A 96 well plate is prepared, in the base of each well a mixture of agar and sugar is added. Drosophila adults are placed individually in each well, and an air permeable cover is put over the top of the well plate. The flies are then individually housed, have a humid environment and some available nutrition.
The well plate, loaded with flies, is inserted into the chamber of the Zantiks MWP unit, and the script is set up to control the environment (temperature and lighting) and the measurement of the distance travelled by each individual fly. The script might typically last for 6 days: during the first three days the well plate might be exposed to 12 hours Light, followed by 12 hours Dark, and then during the subsequent 3 days the plate could be exposed to continuous dark. During all this time the activity (measured as distance travelled) is measured and written to a data file at whatever frequency is required by the experimenter - 5 minute bins are often used.
Video of Drosophila in a 96 well plate during a circadian rhythm study.
Video showing tracking of Drosophila during the study, the crosshairs appear once the fly moves and the unit starts tracking distance moved.