Navigation Links
Day/night cycle even more important to life than previously suspected
Date:9/12/2011

Researchers at USC were surprised recently to discover just how much the rising and setting of the sun drives life on Earth even in unexpected places.

Their findings, which appear this month in the Proceedings of the National Academy of Sciences, "speak volumes to the evolution of life on Earth," according to USC scientist Andrew Y. Gracey.

"Everything is tied to the rotation of the planet," he said.

In all organisms, a certain amount of gene expression (the process by which products are created from the blueprint contained in genes) is rhythmic. In creatures that live on land, that rhythm is unsurprisingly tied to the 24-hour day, known as the circadian cycle.

Mussels which Gracey chose to study instead spend their entire lives in dark shells in an area between the land and the sea, submerged or exposed depending on the tide.

Most of their physical activity is based on the tidal cycle; when mussels are exposed to the air, they close their shells and switch to an anaerobic metabolism, starving for oxygen, and when submerged they breathe and feed.

"It's a really profound change in their biology as they go from sea to land," said Gracey, assistant professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences.

One would expect, then, that the tidal cycle would be the clock that drives their gene expression. But in fact, as Gracey's tests discovered, while a "tidal clock" probably does exist for mussels, the lion's share of their gene expression is instead driven by the circadian cycle.

"The circadian cycle is trumping the tidal cycle," Gracey said.

Gracey and USC graduate student Kwasi Connor constructed an aquarium with an artificial tide by pumping water in and out every six hours. For four days straight, Connor collected samples every two hours getting excellent data, but not much sleep.

"That's why this paper is so good; we have such a high resolution," Gracey said.

Connor shrugged off the sacrifice in the name of science: "It's critical that you get up and do measurements in a precise manner, otherwise you lose the value of the data," he said.

Later, Gracey and Connor ran a similar simulation in a more natural environment by suspending cages of mussels off of a dock, this time for 50 hours.

The results were unexpected. Of the genes that showed rhythmic expression, between 80 and 90 percent were driven by the circadian cycle.


'/>"/>

Contact: Robert Perkins
perkinsr@usc.edu
213-740-9226
University of Southern California
Source:Eurekalert

Related biology news :

1. Cars could run on recycled newspaper, Tulane scientists say
2. Greater seizure frequency seen in women with epilepsy during anovulatory cycle
3. For the first time, the European IVF Monitoring Group reports on cycles using frozen eggs
4. Using recycled cardboard in food packaging risks contaminating food with mineral oils
5. Athletic girls more likely to have impaired bone structure if menstrual cycle stops
6. UNH researchers receive grant for pioneering carbon cycle model
7. The urea cycle: An anabolic steroid for diatoms
8. Scientists discover animal-like urea cycle in tiny diatoms in the ocean
9. Silver cycle: New evidence for natural synthesis of silver nanoparticles
10. Antarctic icebergs play a previously unknown role in global carbon cycle, climate
11. Challenges for biofuels: New life cycle assessment report from Energy Biosciences Institute
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/21/2016)... WAKEFIELD, Massachusetts , March 22, 2016 ... and facial recognition with passcodes for superior security ... MESG ), a leading provider of secure digital communications ... pilot their biometric technology and offer enterprise customers, particularly ... provide secure facial recognition and voice authentication within a ...
(Date:3/15/2016)... New York , March 15, 2016 ... new market report published by Transparency Market Research "Digital Door ... Trends and Forecast 2015 - 2023," the global digital door ... US$ 731.9 Mn in 2014 and is forecast to grow ... 2023. Growth of micro, small and medium enterprises (MSMEs) across ...
(Date:3/14/2016)... March 14, 2016 http://www.apimages.com ... --> - Renvoi : image disponible via ... --> --> DERMALOG, le ... de nouveaux lecteurs d,empreintes digitales pour l,enregistrement des ... sera utilisé pour produire des cartes d,identité aux ...
Breaking Biology News(10 mins):
(Date:5/2/2016)... , ... May 02, 2016 , ... ... its clients in mind, the fresh look and added functionality give the agricultural ... years have seen a dynamic shift in agriculture – from precision farming via ...
(Date:4/29/2016)... (PRWEB) , ... April 29, 2016 , ... ... medical devices used in spinal surgical procedures, today announced the completion of a ... value proposition for current and future customers and partners. Kohlberg & Company, ...
(Date:4/29/2016)... -- Elekta is pleased to announce that ... treatment planning software, is available for clinical release. Real-world ... version 5.11 provides significant performance speed enhancements over prior ... four times faster than in previous versions of ... Monte Carlo algorithm, users can ...
(Date:4/28/2016)... York, NY (PRWEB) , ... April 28, 2016 ... ... QuickSTAT has made significant investments in recruiting top industry experts, and expanding its ... Platform, which provides industry-leading tools for clients to manage their clinical trial projects. ...
Breaking Biology Technology: