Why Circadian Timing Is Everything

Mar 3, 2017

(Editor's Note: Joanna Chiu will be featured on Capital Public Radio's "Insight with Beth Ruyak" from 9 to 10 a.m., Tuesday, March 7. See http://www.capradio.org/insight)

If you want to know more about circadian timing and why "circadian timing is everything"--from human beings to fruit flies--don't miss the Science Café session on Wednesday night, March 8 at Davis.

Molecular geneticist Joanna Chiu, vice chair of the UC Davis Department of Entomology and Nematology, will speak on "Circadian Timing Is Everything: From a Good Night's Sleep to Minimizing Insecticide Use" at the Science Café session at 5:30 p.m., Wednesday, March 8 in the G St. Wunderbar, 28 G St., Davis.

Professor Jared Shaw of the UC Davis Division of Math and Physical Science is hosting the informal session. Free and open to all interested persons, it is sponsored by the Capital Science Communicators and the UC Davis Department of Chemistry. Science Café events take place in casual settings and aim to feature an engaging conversation with a scientist about a particular topic.

Chiu, an associate professor who specializes in molecular genetics of animal behavior, joined the UC Davis Department of Entomology faculty in June 2010. She received her doctorate in molecular genetics from the Department of Biology at New York University.

"All living things on our planet, from bacteria to humans, organize their daily activities around the perpetuating 24-hour day-night cycles, the result of earth rotating on its own axis and orbiting around the sun," Chiu says. "In order for organisms to anticipate predictable variations in their environment that naturally occurs over the 24-hour cycle and coordinate their physiology and behavior to perform at their best, they rely on an internal biological clock. At the science cafe presentation, I will discuss how this internal clock, termed the circadian clock, affects many important aspects of our lives, including the timing of when we feel tired and want to go to bed, the time-of-day our immune systems are most susceptible to pathogen attack, and even when medicines should be taken to give you 'the most bang for your buck.'" In addition, I will discuss the consequences of when the circadian clock is 'broken' or 'off-kilter' because of diseases, work-schedule, jetlag, and light pollution."

Back in 2011, Chiu and colleagues from Rutgers University, the State University of New Jersey, published their work on the fruit fly, Drosophila melanogaster, describing how they identified a new mechanism that slows down or speeds up the internal clock of fruit flies. That research, published in the journal Cell, has important implications: it could lead to discoveries on alleviating human sleep disorders.

By mutating one amino acid in a single protein, “we changed the speed of the internal clock and flies now ‘think' it is 16 hours a day instead of 24 hours a day,” Chiu explained in a 2011 interview.  “Our goal, of course, is not to trick flies into thinking the day is shorter or longer, but to dissect this complex phospho-circuit (phosphorylation sites) that controls clock speed in metazoans.”

“Living organisms—plants, animals and even bacteria—have an internal clock or timer that helps them to determine the time of day," she said in that 2011 interview. "This internal clock is vital to their survival since it allows them to synchronize their activity to the natural environment, so that they can perform necessary tasks at biologically advantageous times of day.”

“A functional clock is required to generate proper circadian rhythms of physiology and behavior including the sleep-wake cycle, daily hormonal variations and mating rhythms,” Chiu said.  “Based on genetics, molecular biology and biochemical experiments performed in many different model organisms, we know that the speed of the internal clock is controlled by a core set of circadian proteins."

So if you aren't getting that good night's sleep and you're wondering about that internal clock, be sure to head over to the G St. Wunderbar on March 8. You'll learn the connection between circadian timings and minimizing insecticide use, too.