Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Molecular imaging may lead to earlier diagnosis of childhood respiratory virus

20.04.2006
Scientists have used a powerful molecular imaging technique to see inside living cells infected with the most pervasive and potentially fatal childhood respiratory virus known to medicine -- respiratory syncytial virus (RSV).

The technique is yielding insight on viruses – such as RSV, human influenza, hepatitis C, West Nile virus and severe acute respiratory syndrome (SARS) -- that replicate with the help of proteins encoded by ribonucleic acid (RNA) inside the cell. Ultimately, the research could to lead to early and rapid detection of viral infection and the design of new antiviral drugs.


An epi-fluorescence microscopy image shows human RSV viral RNA in aggregates, called inclusion bodies, and in filament form, growing in green monkey kidney cells, using molecular-scale probes called molecular beacons molecular beacons. Credit: Image Courtesy of Phil Santangelo


Confocal microscopy images reveal the three-dimensional structure of bovine RSV viral RNA in living, infected bovine nasal cells using molecular-scale probes called molecular beacons. Credit: Image Courtesy of Phil Santangelo

Scientists and engineers at the Georgia Institute of Technology and the University of Georgia are studying bovine and human RSV with molecular-scale probes – called molecular beacons – that are engineered oligonucleotides (short sequences of RNA or DNA) shaped like a hairpin with a fluorescent dye molecule on one end and a quencher molecule on the other end. They are designed to fluoresce only when they bind to a complementary target – in this case, RSV genomic RNA.

"For the first time, we were able to visualize an important part of the RSV virus -- its genome -- in live, infected cells," said Phil Santangelo, a research engineer in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. "Our molecular beacons attach to the virus and glow inside infected cells as the virus grows, replicates and infects other cells. We can now see that happen in real time in cultures in the lab.

"That’s very different from how scientists have studied viruses in past; they’ve looked at viruses in fixed (or preserved) cells," he added. "…. Within the first week of studying human RSV in living cells, I learned something new because I was looking at it live."

Molecular beacons were originally developed at the Public Health Research Institute in New Jersey in the late 1990s. They were initially used for in vitro assays outside cells. But Santangelo and former Georgia Tech Ph.D. student Nitin Nitin, now a postdoctoral researcher at Rice University, devised methods for getting the beacons inside the cell without destroying the probe and without changing the cells.

Santangelo will give an invited presentation on his research on April 20 at the Materials Research Society meeting in San Francisco. The research is funded under a National Institutes of Health grant to Professors Shuming Nie and Gang Bao – both in the Department of Biomedical Engineering at Georgia Tech and Emory -- to develop new, high-sensitivity live-cell probes. In this study, Santangelo, who works for Bao, collaborated with Amelia Woolums, an associate professor of large animal medicine at UGA.

They determined their molecular beacon techniques deliver high-sensitivity and high-specificity results in both bovine and human RSV strains. "The RSV genome is interesting in that it is 15,000 nucleotides long, and one of its RNA sequences repeats itself nine times," Santangelo explained. "So we were able to bind up to nine probes to that sequence, and that helped us achieve very high sensitivity to the virus. In the human virus, in fact, we were able to see a single RSV virion."

Also, researchers were able to detect virion aggregates in bovine RSV within the first day in culture, Santangelo noted. Typically, veterinarians cannot detect RSV until after five or six days of incubation.

Bovine RSV can be a major problem in cows, which represent a good animal model for human RSV. Calves have RSV symptoms similar to those in human babies, and the disease pathology is similar. So studying bovine RSV yields information about the strain that infects humans, he added. Also in this study, researchers used confocal microscopy to view very thin sections of the RSV viral genome in live, infected cells. This technique allowed them to reconstruct the viral RNA aggregates in three dimensions.

"Most pathologists look at thick sections of RSV in formaldehyde, but our 3D structures are more fluid and amorphous than the solid structures pathologists have observed," Santangelo said. "The more we know about how RSV really looks, the more we’ll understand about its pathogenesis."

RSV is the most important cause of respiratory infection in young children worldwide, infecting virtually every child in the first few years of life. Immunity is feeble and fleeting, and repeated infections are the rule. One in every 100 or 200 infected infants requires hospitalization, usually for bronchiolitis. There is not yet an effective vaccine for RSV, and current anti-viral drugs are in their infancy in terms of efficacy, Santangelo noted.

Ultimately, researchers want to conduct in vivo testing, but must first adapt their molecular beacons technology for that purpose, Santangelo said. "In the nearer term, we hope to use molecular beacons to detect RSV in clinical samples like with those taken with a nasal swab. We might be able to detect RSV in its first day of incubation and make an early diagnosis,’’ he added.

The researchers also hope their research will lead to development of a suite of anti-viral drugs for treating RSV and other viruses, including human influenza.

Jane Sanders | EurekAlert!
Further information:
http://www.gatech.edu

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Safe glide at total engine failure with ELA-inside

27.02.2017 | Information Technology

Fraunhofer IFAM expands its R&D work on Coatings for protection against corrosion and marine growth

27.02.2017 | Materials Sciences

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>