clocks in news

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Articles curated by Prof. Stu Brody and Dr. Anna Kriebs
Write-ups produced by Dr. Anna Kriebs
 

CCB posted, Sep 2017

Body Clocks Control Metabolic Healths

Circadian clocks are crucial for maintaining metabolic health. The brain clock regulates sleep and activity cycles, as well as the timing of other behaviors, like feeding, while clocks in peripheral tissues coordinate daily rhythms of physiology and metabolism. Clocks, for example in the liver and pancreas, regulate proper responses to food consumption. Evidence suggests that meal timing, not only calorie count, affects weight gain, as discussed in the FiveThirtyEight article linked to below.

To further dissect the mechanisms underlying health benefits through restriction of food intake the laboratories of Profs. Carla Greene and Joseph Takahashi developed an automated feeder system that allows precise control of the amount, duration and timing of food availability in animal studies. Applying this system to several commonly used feeding paradigms, like temporal restriction and caloric restriction, showed that calorically restricted mice lost weight only when fed during the night, the animal’s active period, not when fed during the day. The study also revealed that calorie restriction altered running wheel activity and that activity patterns varied over the course of the study, underlining the plasticity of feeding and activity behavior. The authors hope that their new feeder system will help scientists assess the respective contributions of reduced calorie count and timing of food intake to increased longevity observed with calorie restriction regiments.

Read more here:
FiveThirtyEight article:
https://fivethirtyeight.com/features/when-should-we-eat/

Original article:
http://www.sciencedirect.com/science/article/pii/S1550413117303492?via%3Dihub

UT Southwestern news release:
http://www.utsouthwestern.edu/newsroom/news-releases/year-2017/jul/lifespan-research-takahashi.html

Food Network:
http://blog.foodnetwork.com/healthyeats/2017/09/03/why-when-you-eat-may-be-as-important-as-what-you-eat/

 


CCB posted, Sep 2017

What Sunscreen and Eating Time Have in Common

Circadian clocks are present in virtually all tissues of the body to optimally regulate tissue specific functions, e.g. the skin circadian clock protects from UV-induced DNA damage, at least in part, by increasing the expression of DNA repair machinery during the day, when skin is exposed to sunlight.

Time-telling external stimuli that enable proper circadian synchronization to the environment include light and food availability. While light received through the eyes allows the master circadian clock in the brain to tell the time-of-day and synchronize peripheral circadian clocks, circadian oscillations, especially in metabolic organs such as the liver, can be shifted relative to brain-time through time-restricted feeding.

A new study from the laboratory of Prof. Bogi Andersen at the University of California, Irvine, now shows that the skin circadian oscillator is also sensitive to feeding time. Comparing circadian rhythms of gene expression in mice that received food at different times of the day or at night showed that skin circadian phase was shifted in response to feeding time. The authors also demonstrate that animals that feed at night, like they naturally would, are more sensitive to UVB-induced damage at night compared to the day. However, day-time feeding reverses the diurnal sensitivity to UVB-induced DNA damage. While it is unclear how these results translate to humans, this study reveals an unanticipated connection between the circadian timing cue, feeding time, and the skin circadian clock.

Read more here:
Original article:
http://www.sciencedirect.com/science/article/pii/S2211124717309889

UT Southwestern news release:
http://www.utsouthwestern.edu/newsroom/news-releases/year-2017/aug/eating-affects-skin-protection.html

Quartz:
https://qz.com/1062687/late-night-snacking-increases-your-risk-of-sunburn/?mc_cid=a6b124a622&mc_eid=043754622c

 


CCB posted, Apr 2017

Night Owl Genetics

The recommendation: “Early to bed, and early to rise” is not for everyone. Preference for sleep timing, or chronotype, is determined by the circadian clock. Roughly, there are morning larks and night owls. Chronotype can determine compatibility with certain social schedules and extreme chronotypes can be very disruptive to the regular day-to-day. Recently, researchers at Rockefeller University discovered the genetic underpinnings of a slow circadian clock that caused delayed sleep phase disorder (DSPD). The study from the laboratory of Prof. Michael Young, a member of the CCB advisory board, lead by Dr. Alina Patke linked the disorder to a variant of the CRY1 gene, a component of the mammalian circadian clock. The resulting protein product was missing a small portion in the C-terminal tail. This shorter CRY1 turned out to be a more potent version of the full length form effectively slowing down circadian time. While there are currently no treatment options targeting CRY1 this finding is still highly relevant and could encourage development of the same since this gene variant is likely present in one out of 75 individuals.

Read more here:
CBC News
http://www.cbc.ca/news/technology/night-owl-gene-1.4069398

NBC News
http://www.nbcnews.com/health/health-news/gene-mutation-affects-sleep-turning-people-martians-n743526

Live Science
https://www.livescience.com/58573-delayed-sleep-phase-disorder-linked-to-gene-mutation.html

Original article:
http://www.cell.com/cell/pdf/S0092-8674(17)30346-X.pdf

 


CCB posted, Mar 2017

Dreams of Sounds that Enhance Memory

Anecdotally, a good night’s sleep is one of the most frequently prescribed remedies. In fact, sleep is crucial for physical and mental well-being. Among other things, memories are solidified during sleep. As both sleep and memory change over the course of a lifetime, researchers are exploring the interconnection between sleep, memory, and aging. Scientists at Northwestern University Medical School focused on decreasing slow wave activity, a sleep stage associated with the ability to recall factual information and experiences, in adults 60 years and older. The team of CCB advisory board member Prof. Phyllis Zee reports that sound stimulation during certain parts of the slow wave activity improved test subjects’ performance in memory tests the next day. This exciting new finding could lead to easy, non-invasive interventions to prevent age-related memory decline.

Read more here:
WTTW (Chicago PBS):
http://chicagotonight.wttw.com/2017/03/08/study-waterfall-sounds-enhance-deep-sleep-memory-older-adults

Original article:
http://journal.frontiersin.org/article/10.3389/fnhum.2017.00109/full

 


CCB posted, Feb 2017

The Sunflower Circadian Clock: A Head Turner

Plants are often perceived as immobile. However, circadian biologists, dating back to the French scientist Jean-Jaques de Mairan in the 1700(s), knew that plants show daily rhythms of movement. More recently, in an elegant study, the team of Prof. Stacey Harmer from UC Davis, a CCB Associate member, showed that the east to west rotation of young sunflower plants over the course of the day is controlled by an internal circadian clock and helped the young flowers to grow bigger than their sibling plants whose movement was impeded. While young sunflowers rotated their heads to follow the sun, this behavior stopped in adult sunflowers, which faced perpetually east. Adult flowers have evolved to face the rising sun because the warmth helps them to attract pollinators. This study was published in the journal Science and featured in the Los Angles Times in August of 2016.

Read more here:
LA Times article:
http://www.latimes.com/science/sciencenow/la-sci-sn-sunflowers-direction-20160804-snap-story.html

Original article:
http://science.sciencemag.org/content/353/6299/587

 


CCB posted, Feb 2017

Reset Your Circadian Clock by Going Camping

The expression “to go to bed with the chickens” refers to a time when people’s sleep wake cycle was dictated by the natural day. In modern society this is no longer the case. We often stay up long after dusk, since we don’t have to rely on natural light to do our work. As a consequence our biological night, as defined by elevated levels of the sleep hormone melatonin, begins long after dark. Therefore, when it is time to rise in the morning melatonin levels may still be high, making getting out of bed a challenge. The team of Prof. Kenneth Wright from the University of Colorado, Boulder, reports that camping might help. Their unique study, published in the journal Current Biology and featured in this Los Angles Times article, shows that a weekend camping trip in the Rocky Mountains, away from electric lighting, was sufficient to shift the melatonin profile of campers more than an hour earlier compared with the control group that stayed home. Additionally, the researchers showed that the melatonin profiles mirror seasonal changes in day length. Therefore, maximizing light exposure during the day as well as minimizing it during the night is key to changing sleep patterns

Read more here:
LA Times article:
http://www.latimes.com/science/sciencenow/la-sci-sn-camping-better-sleep-20170202-story.html

Original article:
http://www.cell.com/current-biology/fulltext/S0960-9822(16)31522-6