(Press-News.org) COLLEGE STATION, Sept. 9, 2010 – DNA analysis is poised to experience a significant advancement thanks to the work of a Texas A&M University chemical engineer, who has discovered a way to achieve more effective separation of DNA fragments.
Working with a widely used gelatin substance known as a hydrogel, Victor M. Ugaz, associate professor in the university's Artie McFerrin Department of Chemical Engineering, and graduate student Nan Shi have been able to determine the specific type of conditions that result in the optimum gel pore structure for separation of a wide range of DNA fragment sizes. Their findings appear in the Sept. 3 edition of the journal Physical Review Letters.
"It changes the way you think about the entire process because these findings demonstrate a rational way to connect the pore structure of the gel quantitatively to the mechanism by which the DNA moves through the gel," Ugaz explains. "Researchers can now actually design gels to specifically harness certain effects, and they will need this information we have found to do that."
The enhanced separation technique, Ugaz notes, could benefit a wide array of fields that utilize DNA analysis, including biomedical research, forensics and genetic engineering.
Key to Ugaz's findings is the manner in which DNA fragments move through a hydrogel. Employing a process called "electrophoresis," researchers who study DNA typically embed negatively charged DNA into a porous hydrogel. They then apply an electric field which causes the DNA fragments to move through the pores of the hydrogel. Naturally, smaller DNA chains move faster through the maze of pores than longer strands of DNA.
However, when DNA chains are roughly the same size as the pores through which they are attempting to pass, a process called "entropic trapping" takes place, Ugaz notes. During this process, the naturally coiled DNA fragment, in a sense, has to unthread a bit to pass through a pore, he says. Because the fragment wants to return to its coiled shape, it quickly squeezes through the smaller pore so that it can enter a larger pore where there is enough room for it to return to its natural shape.
Harnessing this entropic trapping effect for separation through a hydrogel marks a significant advancement in DNA studies, Ugaz says.
Although it has long been predicted that entropic trapping effects can potentially benefit a wide variety of applications including separation technologies, actually figuring out how to use this phenomenon previously has been difficult in hydrogels because it has not been clear how this transport mechanism is linked to the gel's porous structure, Ugaz explains.
In other words, hydrogels need to have very specific properties such as pore size distribution, and prior to these findings, there has been no way to know how to choose the right hydrogel that has the right properties, Ugaz notes.
"You want to be able to detect the smallest possible difference in size between DNA fragments," Ugaz explains. "The size of the fragments may be very close, and you may need to detect a difference of one unit in size. To do this, you would want to be able to specifically construct a hydrogel with the necessary pore structure to achieve this."
Ugaz's research provided the "instructions on how to do just that.
"We have a better picture of how to do this than what has existed," Ugaz says. "We know what the gel needs to look like and how it needs to be prepared.
"We're able to understand how to construct a gel that would allow DNA to move via an entropic trapping method that enhances separation performance and in turn leads to more effective analysis. This finding could have enormous implications by helping remove current barriers to separation efficiency"
INFORMATION:
Contact: Victor Ugaz at (979) 458-1002 or via email: ugaz@tamu.edu or Ryan A. Garcia at (979) 845-9237 or via email: ryan.garcia99@tamu.edu.
END
As speech recognition systems become more commonplace - on the computer desktop top, at the call centre and even in the car - it is increasingly important to ensure that the voice signal is as clear as possible before it is processed by a computer and acted upon. It could mean the difference between anything from a profitable financial deal to a safe vehicle or aircraft maneuver. Similarly, mobile phone conversations and even the clandestine recording of speech for security and law enforcement purposes could benefit.
Now, researchers at the University Campus in Tunis, ...
The existence of Dark Matter particles in the Sun's interior seems inevitable, despite dark matter never having been observed (there or elsewhere), despite intensive ongoing searches. Once gravitationally captured by the Sun, these particles tend to accumulate in its core.
In a paper to be published in the scientific journal " Science", Dr. Ilidio Lopes and Professor Joseph Silk propose that the presence of dark matter in the Sun's interior causes a significant drop in its central temperature. Their calculations have shown that, in some dark matter scenarios, an isothermal ...
A survey in the latest issue of the Hastings Center Report found that most hospices in Oregon, the first state to legalize physician-assistance in dying, either do not participate in or have limited participation in requests for such assistance. Both legal and moral reasons are identified.
This finding is significant because hospices are considered important for assuring that physician-assisted death is carried out responsibly, write the authors, Courtney S. Campbell, the Hundere Professor of Religion and Culture at Oregon State University, and Jessica C. Cox, the Hundere ...
Ghent, 9 September 2010 – Factoring the planet's multi-trillion dollar ecosystem services into policy-making can help save cities and regional authorities money while boosting the local economy, enhancing quality of life, securing livelihoods and generating employment.
This is the finding from a major international study, launched in a report by TEEB for Local and Regional Policy Makers, being released in Belgium, Brazil, India, Japan and South Africa.
In the Framework of the Belgian Presidency of the European Union, the Flemish Ministry of Environment, Nature and ...
New Rochelle, NY, September 8, 2010—Pediatric-onset obsessive compulsive disorder (OCD) and Tourette's disorder (TD) share similarities in their underlying genetic and environmental factors, psychiatric features, and treatment methods. Advances in understanding the neurobiological basis of these disorders and discovering new and more effective therapies are highlighted in a special issue on OCD and TD in Journal of Child and Adolescent Psychopharmacology, a peer-reviewed journal published by Mary Ann Liebert, Inc. (www.liebertpub.com). The entire issue is available free ...
(SACRAMENTO, Calif.) — Among Asian-Americans living in California, Laotian/Hmong-Americans have the lowest survival rates for the most common type of liver cancer, a new study by researchers with the UC Davis School of Medicine has found.
The study, the largest population-based examination of liver cancer rates among Asian-Americans, highlights a profound disparity that calls for targeted outreach to detect and treat the disease earlier among Laotian/Hmong-Americans, said Moon Chen Jr., a professor of hematology and oncology in the UC Davis School of Medicine.
"We ...
(SACRAMENTO, Calif.) — In an unanticipated finding, researchers at the UC Davis School of Medicine have discovered that, during early adulthood, the brain produces new excitatory neurons, and that these neurons arise from non-neuronal support cells in an area of the brain that processes smell.
The study, conducted in mice, is the first to demonstrate that pyramidal neurons in the mature brain stem are generated by precursors of glial cells — non-neuronal support cells — and that these new neurons likely are capable of transmitting information to widespread regions of ...
The widespread use of a simplified clinical tool to estimate future coronary risk could lead to the classification of millions of Americans into different risk groups than when using the original, "gold-standard" tool. Millions of patients may have been misclassified into higher-risk groups and therefore potentially over-treated, while others may have ended up in lower-risk groups and therefore potentially under-treated for heart disease. The study¹, led by William Gordon from Weill Cornell Medical College in the US and colleagues, is published in the Journal of General ...
A method that is widely used to predict the risk of a major coronary event may over- or underestimate risk for millions of Americans, according to a study directed by a researcher at the San Francisco VA Medical Center and the University of California, San Francisco.
The method in question is the simplified version of the so-called Framingham model, which is used to estimate a patient's 10-year risk of a heart attack, stroke, or other coronary event based on risk factors such as age, cholesterol levels, blood pressure, and smoking. National guidelines recommend using ...
Rosemont, Ill. – The American Academy of Orthopaedic Surgeons (AAOS) recently approved and released an evidence-based clinical practice guideline on the diagnosis of periprosthetic joint infections of the hip and knee. Clinical practice guidelines are one avenue the Academy uses to ensure that patients receive high quality care. A periprosthetic joint infection occurs when bacteria or other foreign organisms enter the wound during or at any point following joint replacement surgery, sometimes even years after surgery. An infection can cause the joint to be painful or cause ...
