(Press-News.org) A Lawrence Livermore National Laboratory physicist and his colleagues have found a new application for the tools and mathematics typically used in physics to help solve problems in biology.
Specifically, the team used statistical mechanics and mathematical modeling to shed light on something known as epigenetic memory -- how an organism can create a biological memory of some variable condition, such as quality of nutrition or temperature.
"The work highlights the interdisciplinary nature of modern molecular biology, in particular, how the tools and models from mathematics and physics can help clarify problems in biology," said Ken Kim, an LLNL physicist and one of the authors of a paper appearing in the Feb. 7 issue of Physical Review Letters.
Not all characteristics of living organisms can be explained by their genes alone. Epigenetic processes react with great sensitivity to genes' immediate biochemical surroundings—and further, they pass those reactions on to the next generation.
The team's work on the dynamics of histone protein modification is central to epigenetics. Like genetic changes, epigenetic changes are preserved when a cell divides. Histone proteins were once thought to be static, structural components in chromosomes, but recent studies have shown that histones play an important dynamical role in the machinery responsible for epigenetic regulation.
When histones undergo chemical alterations (histone modification) as a result of some external stimulus, they trigger short-term biological memory of that stimulus within a cell, which can be passed down to its daughter cells. This memory also can be reversed after a few cell division cycles.
Epigenetic modifications are essential in the development and function of cells, but also play a key role in cancer, according to Jianhua Xing, a former LLNL postdoc and current professor at Virginia Tech. "For example, changes in the epigenome can lead to the activation or deactivation of signaling pathways that can lead to tumor formation," Xing added.
The molecular mechanism underlying epigenetic memory involves complex interactions between histones, DNA and enzymes, which produce modification patterns that are recognized by the cell. To gain insight into such complex systems, the team constructed a mathematical model that captures the essential features of the histone-induced epigenetic memory. The model highlights the "engineering" challenge a cell must constantly face during molecular recognition. It is analogous to restoring a picture with missing parts. The molecular properties of a species have been evolutionarily selected to allow them to "reason" what the missing parts are based on incomplete information pattern inherited from the mother cell.
INFORMATION:
The research team includes Tech graduate students Hang Zhang and Abhishek Mukhopadhyay and postdoc researcher Xiao-Jun Tian also of Virginia Tech, and Yujin Kim of Foothill High School in Pleasanton, Calif. During this research project, Xing served as a mentor to Yujin Kim.
The research is supported by National Science Foundation grants.
Founded in 1952, Lawrence Livermore National Laboratory provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
New application of physics tools used in biology
2014-02-08
ELSE PRESS RELEASES FROM THIS DATE:
Social or stinky? New study reveals how animal defenses evolve
2014-02-08
When people see a skunk, the reaction usually is "Eww," but when they see a group of meerkats peering around, they often think "Aww."
Why some animals use noxious scents while others live in social groups to defend themselves against predators is the question that biologists Tim Caro of the University of California, Davis and Theodore Stankowich of California State University, Long Beach and sought to answer through a comprehensive analysis of predator-prey interactions among carnivorous mammals and birds of prey.
Their findings appear in the online edition of the ...
Endocrine Society calls for large-scale studies to evaluate testosterone therapy risks
2014-02-08
Chevy Chase, MD—According to a statement issued today by the Endocrine Society, the risks and benefits of testosterone therapy for older men with declining levels of the hormone need to be fully evaluated.
The statement comes in response to recent studies that have raised concerns about the safety of testosterone therapy in older men with a history of heart disease. Two retrospective analyses and one randomized trial supported by the Veterans Health Care System, and the National Institutes of Health found a higher rate of cardiovascular events in men who received testosterone ...
NASA spots very heavy rainfall rates in Tropical Cyclone Edilson
2014-02-08
Imagine receiving as much as 7 inches of rain in one hour. That's about what NASA's TRMM satellite spotted falling in one area within Tropical Cyclone Edilson as it moved over the Southern Indian Ocean.
The Tropical Rainfall Measuring Mission or TRMM satellite is managed by both NASA and the Japan Aerospace Exploration Agency called JAXA. TRMM can read the rate in which rain is falling on Earth while in its orbit high above.
The TRMM satellite had an excellent early morning look at Edilson on February 7, 2014 at 0237 UTC/06:28 local time when it passed directly above ...
Diaphragm pacing in spinal cord injury successful in weaning patients from ventilators
2014-02-08
CLEVELAND – A new study published in the Journal of Trauma and Acute Care Surgery finds that diaphragm pacing (DP) stimulation in spinal cord-injured patients is successful not only in weaning patients from mechanical ventilators but also in bridging patients to independent respiration, where they could breathe on their own without the aid of a ventilator or stimulation.
The stimulation is provided by the Diaphragm Pacing System (DPS), a technology providing electrical stimulation to nerves running through the diaphragm, the major muscle involved in breathing. When stimulated, ...
NASA spots fourteenth tropical cyclone of Southern Indian Ocean season
2014-02-08
The fourteenth tropical cyclone of the Southern Indian Ocean season was born as NASA's Terra satellite passed overhead.
On February 7 at 0900 UTC/4 a.m. EST, Tropical Cyclone 14S had maximum sustained winds near 35 knots/40 mph/62 kph. It was located about 814 nautical miles/936.7 miles/1,508 km east-northeast of Port Louis, Mauritius near 14.8 south and 70.4 east. At that time, 14S was moving to the south near 8 knots/9.2 mph/14.8 kph.
The Joint Typhoon Warning Center noted that multispectral satellite imagery showed that the low-level center is exposed to outside ...
Thinking skills take biggest hit from anxiety in midlife women with HIV
2014-02-08
CLEVELAND, Ohio (Friday, February 7, 2014)—Hot flashes, depression, and most of all, anxiety, affect the thinking skills of midlife women with HIV, so screening for and treating their anxiety may be especially important in helping them function, according to a study just published online in Menopause, the journal of The North American Menopause Society (NAMS). The reproductive stage, whether it was premenopause, perimenopause or postmenopause, did not seem to be related to these women's thinking skills.
The conclusions come from a new analysis of data on 708 HIV-infected ...
WASP gives NASA's planetary scientists new observation platform
2014-02-08
Scientists who study Earth, the sun and stars have long used high-altitude scientific balloons to carry their telescopes far into the stratosphere for a better view of their targets. Not so much for planetary scientists. That's because they needed a highly stable, off-the-shelf-type system that could accurately point their instruments and then track planetary targets as they moved in the solar system.
That device now exists.
NASA's Wallops Flight Facility in Wallops Island, Va., has designed a new pointing system — the Wallops Arc Second Pointer (WASP) — that can point ...
Study provides surprising new clue to the roots of hunger
2014-02-07
BOSTON – While the function of eating is to nourish the body, this is not what actually compels us to seek out food. Instead, it is hunger, with its stomach-growling sensations and gnawing pangs that propels us to the refrigerator – or the deli or the vending machine. Although hunger is essential for survival, abnormal hunger can lead to obesity and eating disorders, widespread problems now reaching near-epidemic proportions around the world.
Over the past 20 years, Beth Israel Deaconess Medical Center (BIDMC) neuroendocrinologist Bradford Lowell, MD, PhD, has been untangling ...
New method developed for ranking disease-causal mutations within whole genome sequences
2014-02-07
Seattle, Wash. and Huntsville, Ala.—Researchers from the University of Washington and the HudsonAlpha Institute for Biotechnology have developed a new method for organizing and prioritizing genetic data. The Combined Annotation–Dependent Depletion, or CADD, method will assist scientists in their search for disease-causing mutation events in human genomes.
The new method is the subject of a paper titled "A general framework for estimating the relative pathogenicity of human genetic variants," published in Nature Genetics.
Current methods of organizing human genetic variation ...
Study identifies protein to repair damaged brain tissue in MS
2014-02-07
Vittorio Gallo, PhD, Director of the Center for Neuroscience Research at Children's National Health System, and other researchers have found a "potentially novel therapeutic target" to reduce the rate of deterioration and to promote growth of brain cells damaged by multiple sclerosis (MS). Current therapies can be effective in patients with relapsing MS, but have little impact in promoting tissue growth.
The brain produces new cells to repair the damage from MS years after symptoms appear. However, in most cases the cells are unable to complete the repair, as unknown ...