Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carnegie Mellon Physicist the First To Measure Energy Released From a Virus During Infection

08.02.2010
Within a virus's tiny exterior is a store of energy waiting to be unleashed.

When the virus encounters a host cell, this pent-up energy is released, propelling the viral DNA into the cell and turning it into a virus factory. For the first time, Carnegie Mellon University physicist Alex Evilevitch has directly measured the energy associated with the expulsion of viral DNA, a pivotal discovery toward fully understanding the physical mechanisms that control viral infection and designing drugs to interfere with the process.

"We are studying the physics of viruses, not the biology of viruses," said Evilevitch, associate professor of physics in the Mellon College of Science at Carnegie Mellon. "By treating viruses as physical objects, we can identify physical properties and mechanisms of infection that are common to a variety of viruses, regardless of their biological makeup, which could lead to the development of broad spectrum antiviral drugs."

Current antiviral medications are highly specialized. They target molecules essential to the replication cycle of specific viruses, such as HIV or influenza, limiting the drugs' use to specific diseases. Additionally, viruses mutate over time and may become less susceptible to the medication. Evilevitch's work in the burgeoning field of physical virology stands to provide tools for the rational design of less-specialized antiviral drugs that will have the ability to treat a broad range of viruses by interrupting the release of viral genomes into cells.

Evilevitch's current findings also have the potential to improve the development of gene therapy, which uses viruses to deliver functional genes directly to human cells to replace defective genes that are causing disease. Gene therapy takes advantage of viruses' modus operandi — injecting genetic material into cells. But instead of forcing in harmful, viral DNA, gene therapy delivers helpful, functional genes. Controlled packaging of the functional genes into the viral delivery system is one of the key factors involved in developing a successful gene therapy.

Many viruses, whether they infect bacteria, plants or animals, are adept at packing long stretches of nucleic acid (DNA or RNA) within their nanometer-sized protein shells. In many of the viruses that contain double-stranded DNA, the DNA gets packaged so tightly that it bends upon itself, resulting in repulsive forces that exert a tremendous amount of pressure on the virus's outer shell, indicating a great amount of stored energy. At the moment of infection, when the DNA is being shot out of the virus, the energy stored in the tightly packed DNA is released and converted into thermal energy.

Evilevitch and his colleagues from Lund University in Sweden, where Evilevitch was previously employed, and the Universite de Lyon in France used an experimental technique known as isothermal titration calorimetry (ITC) to directly measure the heat, and thus the thermal energy, released during viral genome ejection. Until now, only indirect measurements of this energy have been available. They describe this new method in the Feb. 5 issue of the Journal of Molecular Biology.

"We are the first group to use titration calorimetry to study genome release from viruses," Evilevitch said. "In this study, we looked at viruses that infect bacteria, called bacteriophages, as an experimental model system, but ITC can also be applied to other types of viruses. We're currently investigating the rotavirus, which causes stomach flu, using our new technique."

In the Journal of Molecular Biology report, Evilevitch used ITC to measure the thermal energy released during genome ejection, which is the same as the stored internal energy that results from genome packaging. His results, which agree with analytical models and computer simulations, show that the heat released increases as DNA length increases. He also discovered that the ordering of water molecules around DNA strands inside the virus (called hydration entropy) has a tremendous influence on the build up of energy. This unpredicted effect was not accounted for in the previous models.

"Understanding the energy profile for viral genome release provides information on how to interfere with the process. For example, developing ways to decrease the internal energy in viruses could prevent viruses from ejecting their genome and prevent infection," Evilevitch said.

Jocelyn Duffy | EurekAlert!
Further information:
http://www.cmu.edu

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Researchers invent tiny, light-powered wires to modulate brain's electrical signals

21.02.2018 | Life Sciences

The “Holy Grail” of peptide chemistry: Making peptide active agents available orally

21.02.2018 | Life Sciences

Atomic structure of ultrasound material not what anyone expected

21.02.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>