Begin by placing four adult worms on an nematode growth medium or NGM agar plate seeded with E.coli OP50. Grow the first generation worms to starvation on the NGM plate at a temperature of 23 degrees Celsius for seven days. Next, transfer small amounts of dog food agar or DFA medium to the center of a new NGM plate seeded with E.coli OP50.
For optogenetic experiments, pour 40 microliters of all-trans-retinal onto the DFA prior to worm inoculation. Next place, 0.5 milligrams of dog food on the DFA medium, about two millimeters away from the plate lid. Avoid contamination by irradiating the NGM plate with ultraviolet light for 15 minutes.
Gather the starved worms from the NGM plates using sterilized water. Then inoculate the gathered worms onto the DFA medium located on the NGM. Propagate the worms at 23 degrees Celsius, enabling them to climb towards the plate lid over 10 to 14 days.
Increased humidity exhibited larger compartment sizes of the worm network patterns before ultimately collapsing, leaving dormant worm clusters on the inner surface of the lid.