(Press-News.org) 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.
INFORMATION:
This research was funded by the National Science Foundation.
END
Researchers at University Medical Center Utrecht, the Netherlands, have discovered a substance that has an adverse effect on nearly all types of chemotherapy - making cancer cells insensitive to the treatment. Chemotherapy often loses effectiveness over time. It is often unclear how or why this happens.
It now appears that chemotherapy is made ineffective by two types of fatty acid that are made by stem cells in the blood. Under the influence of cisplatin chemotherapy, the stem cells secrete these fatty acids that induce resistance to a broad spectrum of chemotherapies. ...
EAST LANSING, Mich. --- When countries try to work together to limit the effects of climate change, the fear of being the only nation reducing greenhouse gas emissions – while the others enjoy the benefits with no sacrifice – can bring cooperation to a grinding halt.
In a commentary in the Early Edition of the Proceedings of the National Academy of Sciences, Thomas Dietz, professor of sociology and environmental science and policy and assistant vice president for environmental research at MSU, and Jinhua Zhao, director of the MSU Environmental Science and Policy Program ...
Researchers from Mount Sinai School of Medicine have for the first time used several imaging techniques to prove the efficacy of a promising new treatment for atherosclerosis—the build-up of plaque in artery walls that can lead to a heart attack. Using positron-emission tomography (PET)/computed tomography (CT) and magnetic resonance imaging (MRI), the research team showed that dalcetrapib, a novel treatment for atherosclerosis, prevented the progression of disease and reduced vascular inflammation over 24 months. The data are published in the September 12 issue of The ...
EVANSTON, Ill. --- A new Northwestern University study provides compelling evidence that human males are biologically wired to care for their offspring, conclusively showing for the first time that fatherhood lowers a man's testosterone levels.
The effect is consistent with what is observed in many other species in which males help take care of dependent offspring. Testosterone boosts behaviors and other traits that help a male compete for a mate. After they succeed and become fathers, "mating-related" activities may conflict with the responsibilities of fatherhood, ...
CHICAGO – Among patients who have had an ischemic stroke, use of cholesterol-lowering statin medications is not associated with subsequent intracerebral hemorrhage (bleeding in the brain), according to a report published Online First by Archives of Neurology, one of the JAMA/Archives journals.
According to background information in the article, after stroke or transient ischemic attack, patients are at increased risk for recurrent events. Results from the Stroke Prevention by Aggressive Lowering of Cholesterol Levels (SPARCL) trial and the Heart Protection Study (HPS) ...
CHICAGO – Intranasal insulin therapy appears to provide some benefit for cognitive function in patients with amnestic mild cognitive impairment and Alzheimer disease, according to a report published Online First today by Archives of Neurology, one of the JAMA/Archives journals.
According to background information in the article, insulin plays a role in a number of functions of the central nervous system. "The importance of insulin in normal brain function is underscored by evidence that insulin dysregulation contributes to the pathophysiology of Alzheimer disease (AD), ...
CHICAGO – Many U.S. adults believe that only extremely effective drugs without serious adverse effects are approved, but providing explanations to patients highlighting uncertainties about drug benefits may affect their choices, according to a report in the September issue of Archives of Internal Medicine, one of the JAMA/Archives journals. The article is part of the journal's Less Is More series.
Approval from the U.S. Food and Drug Administration (FDA) does not necessarily ensure that a drug has a large or important benefit, or that all serious adverse effects of the ...
CHICAGO – Long-term use of nonaspirin anti-inflammatory drugs (NSAIDs) is associated with an increased risk of renal cell cancer (RCC), according to a report in the September issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
According to background information in the article, in the United States, kidney cancer is the seventh leading type of cancer among men and the ninth leading type of cancer among women. The most common type of kidney cancer, renal cell cancer, accounts for 85 percent of all cases. Analgesics (pain-relieving medications) are ...
CHICAGO – An association has been found between infection associated with cardiovascular implantable electronic devices (CIEDs) and increases in mortality and hospital care costs, according to a report published Online First by Archives of Internal Medicine, one of the JAMA/Archives journals. The article is part of the journal's Health Care Reform series.
Therapy with CIEDs, which include pacemakers, implantable cardioverter-defibrillators and cardiac resynchronization therapy/defibrillator devices, can reduce illness and death rates in appropriately selected patients, ...
Skin Solutions Medical Spa has been serving the Denver Metro area for the past 15 years and was recently nominated for Denver 7's A-List as Denver's best Medical Spa. The spa stands out in the community by providing the highest level of customer service while producing state-of-the-art cosmetic procedures and aesthetic treatments that are safe and effective. The announcement of Express Rejuvenation Day shows the spa's commitment to provide even more quality to their clients and community.
Skin Solutions Medical Spa's new Express Rejuvenation Day was driven by the demand ...
