What We Do In the Lab

This video was made by Advait Pandya and Khalidha Nasiri as their entry for the 2015 NSERC Science, Action! video contest. Their challenge was to explain their research project in 60 seconds. They didn’t make the finals, but they had a great time doing it and we think it’s a winner!

Time-Lapse of Race Tubes of Neurospora

This is the culture system we use in the lab for assaying the circadian rhythm of conidiation (spore-formation). Glass tubes (“race tubes”) about 30 cm long are filled with agar growth medium and inoculated at one end with a bit of fungus. They are then cultured in a constant temperature incubator in constant darkness, with no time-cues from the environment. The fungal mycelium advances down the length of the tube and makes a band of spores about once a day (note the clock times in the upper left). This circadian (daily) rhythm is driven by an internal clock. For routine experiments, we don’t use time-lapse, but we mark the progress of the growth front once a day under red light. (The fungus is sensitive only to blue light.) This video was made by a work/study student, Julia Ishakova, using our standard laboratory strain under red light.

Time-Lapse of Laboratory Neurospora on Corn

Agar medium in race tubes is not, of course, the natural habitat of Neurospora. It grows in nature on burned plant material and is one of the first colonizers to appear after a fire. We gave our laboratory Neurospora a more natural substrate by cooking corn, eating the kernels, and splitting the cobs. The bands of orange spores are formed as the colony expands. This video was made in the York Biology greenhouse with a natural light/dark and temperature cycle, using a flash for photography.

Time-Lapse of Wild-Type Neurospora on Corn

The laboratory strain of Neurospora we usually use carries two mutations that make the cultures easier to handle and the bands of spores easier to see. We wondered if the wild-type strain with no mutations would also make bands under natural conditions. Here it is on our corn substrate. Conclusion: No bands! But look carefully and you will see that once a day all the newly-formed mycelium (the mat of fungal hyphae) turns orange simultaneously as the spores “bloom.” So the daily rhythm of spore-formation is still functioning. (The flashing effect is from water condensing on the lens of the camera. It was very humid in the greenhouse.) This video was made using the same techniques as the laboratory strain video.

Fun with time-lapse: Leaf movements of clover, light/dark

This is a time-lapse video of common white clover (Trifolium repens) over six days. It was made in a light/dark cycle with a flash taking a photo every 10 minutes. The leaves close in the dark phase and open in the light phase, showing nyctinastic (night) movement. Are the leaves simply responding to the environment and closing in direct response to darkness? No! See the next video…

Leaf movements of clover in light/light

This time-lapse video of white clover was made in constant light conditions, immediately after the previous video ended. The leaf movements continue because they are controlled by an internal circadian clock, not by the external light/dark cycle. The leaves begin to fall out of step with each other after a few days, showing that the leaves are not synchronized with each other but are acting independently.

More Fun with Time-Lapse: Amaryllis flowering

This time-lapse video was made under a constant fluorescent light with contribution from a window. It covers about 3 days and nights. These flowers dance with a daily rhythm!

Nicholas Mrosovsky Tribute

This video was presented at the Second Conference of the Canadian Society for Chronobiology, Concordia University, Montreal, May 29-31, 2015. It is a tribute to the life and work of Nicholas Mrosovsky, an eminent Canadian chronobiologist, who passed away in February, 2015.