Every year, Nikon asks photographers and scientists to enter their most magnificent microscopic photos into the Small World photomicography competition, and every year, they dazzle. Here are three of the coolest photos from among this year’s winners.
Jennifer Peters and Michael Taylor, St. Jude Children’s Research Hospital/Nikon Small World
First Place: This winning photo depicts the blood-brain barrier, the seal between capillaries and the brain, of a live zebrafish embryo. To produce the image, researchers genetically engineered components of the barrier to fluoresce under a confocal microscope, took a series of photos at 20x magnification, then combined the images to create this one. This is believed to be the first time the developing blood-brain barrier of a live animal has been captured on film.
A fruit fly in its natural habitat
In circadian rhythm research, the single best-studied organism is probably the fruit fly. It was through grinding up the heads of countless flies that scientists discovered molecular clock genes, which were then found to play similar roles in humans. But when it come to how actual fly behavior changes in a 24-hour period, a recent study questions whether conventional lab wisdom is wrong. A new paper in Nature put those same lab-bred fruit flies in a natural habitat and observed bursts of activity at unexpected times.
Two set of experiments, one in Italy and another right in the backyard of the lead researcher in England, found that flies are diurnal. That means they’re most active during the day, specifically the afternoon with small upticks in activity during dawn and dusk. While this may not sound exciting by itself, it upends decades of lab research that said fruit flies take a “siesta” during the day and have dramatic bursts of morning and evening activity. This behavior is so well-accepted that there are neuron clusters of the fly brain called morning and evening oscillators whose activity corresponds to the bursts.
Outdoors, however, temperature fluctuations and the gradual rising or setting of the sun offer much richer information than a temperature-controlled incubator where lights flick on at ZT 0 and off at ZT 12. (ZT stands for Zeitgeber Time, which means “time giver” in German.) Since the morning burst of activity comes just before sunrise, scientists had thought it was governed by an internal molecular clock. Data from this new study suggest this morning activity is actually set by warming temperatures leading up to sunrise.