A Johns Hopkins biologist has been selected by the Partnership for Undergraduate Life Sciences (PULSE) as one its new Vision and Change Leadership Fellows, a group charged with spending a year identifying and recommending ways to improve undergraduate life sciences education. Joel Schildbach, a biology professor and director of undergraduate studies at Johns Hopkins’ Krieger School of Arts and Sciences, is one of 40 faculty members selected from 250 applicants from 24 states and the U.S. Virgin Islands by PULSE, a joint initiative of the National Science Foundation, the Howard Hughes Medical Institute and the National Institutes of Health.
Recent news from The Johns Hopkins University
This section contains regularly updated highlights of the news from around The Johns Hopkins University. Links to the complete news reports from the nine schools, the Applied Physics Laboratory and other centers and institutes are to the left, as are links to help news media contact the Johns Hopkins communications offices.
The old adage “Looks can be deceiving” certainly rings true when it comes to people. But it is also accurate when describing special, light-sensing cells in the eye, according to a Johns Hopkins University biologist. In a study recently published in Nature, a team led by Samer Hattar of the Department of Biology at the Krieger School of Arts and Sciences and Tudor Badea at the National Eye Institute found that these cells, which were thought to be identical and responsible for both setting the body’s circadian rhythm and the pupil’s reaction to light and darkness, are actually two different cells, each responsible for one of those tasks.
We run our modern lives largely by the clock, from the alarms that startle us out of our slumbers and herald each new workday to the watches and clocks that remind us when it’s time for meals, after-school pick-up and the like. In addition to those ubiquitous timekeepers, though, we have internal “clocks” that are part of our biological machinery and which help set our circadian rhythms, regulating everything from our sleep-wake cycles to our appetites and hormone levels. Light coming into our brains via our eyes set those clocks, though no one is sure exactly how this happens. Johns Hopkins biologist Samer Hattar, in collaboration with scientists at the University of Southern California and Cornell University, however, has unlocked part of that mystery recently in a study that found that rod cells – one of three kinds of exquisitely photosensitive cells found in the retina of the eye – are the only ones responsible for “setting” those clocks in low light conditions. What’s more, the study found that rods – which take their name from their cylindrical shape – also contribute (along with cones and other retinal cells) to setting internal clocks in bright light conditions. The study appeared in a recent issue of Nature Neuroscience.
It would make the perfect question for the popular television show “Are You Smarter than a 5th Grader:” What parts of the eye allow us to see? The conventional wisdom: rods and cones. The human retina contains about 120 million rods, which detect light and darkness, shape and movement, and about 7 million cones, which in addition detect color. Without them, or so we are taught, our eyesight simply would not exist. But that might not be true, according to a study — published July 15 in the journal Neuron and led by Johns Hopkins biologist Samer Hattar — that provides new hope to people who have severe vision impairments or who are blind.