Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers seek to clone ’mad cow disease’ resistant cattle strain

09.01.2004


Scientists in the Virginia-Maryland Regional College of Veterinary Medicine (VMRCVM) at Virginia Tech are trying to clone cattle that are genetically incapable of developing "Mad Cow Disease."

As federal and state government officials grapple with strategies to limit the economic and health risks associated with the troublesome discovery of the nation’s first case of Bovine Spongiform Encephalopathy (BSE) – or "Mad Cow Disease"-- Will Eyestone, research associate professor in Large Animal Clinical Sciences, and Bill Huckle, associate professor of biomedical science, are conducting important research with the little understood molecules believed to cause the deadly brain-wasting disease.

Eyestone, a molecular reproductive biologist who was senior research scientist for PPL Therapeutics, the organization that cloned Dolly the sheep, now heads the VMRCVM’s transgenic animal research program.



Most people think of disease as being caused by infectious organisms like bacteria, viruses, rickettsia, protozoa or fungi, explains Eyestone. Those microorganisms reproduce themselves to cause disease in fairly conventional ways, either inside a cell or elsewhere in the body.

But prions behave very differently than these more common disease-causing organisms, explains Eyestone. Prions are actually a form of protein that naturally occur in all mammals, though scientists remain uncertain about the exact purpose they serve in advanced mammals like humans. Transmissible spongiform encephalopathies like BSE and new variant Creutzfeldt-Jacob Disease (vCJD), the human form of the disease, are believed to occur when the non-pathogenic prions that normally reside in mammalian nervous systems are converted into pathogenic forms.

Proteins, the building blocks of metabolic processes, are long chains of amino acids that fold in upon themselves in predictable patterns and shapes that result from the bio-electrical relationships that exist between individual molecules, according to Eyestone. Proteins normally "fold" in only one way. But when the "normal" prions are infected by pathogenic prions, they begin to "fold" in another way that leads to disease.

In the case of BSE and vCJD, pathogenic prions introduced from contaminated food sources interact with normal prions in the body and transform them into the lethal agents that eventually create the "Swiss cheese-like" lesions in the brain that cause the devastating neurological symptoms of the disease.

The pathogenic prions that are ingested by cattle in contaminated feed do not seem to be affected by the normal enzymatic activity of the digestion process, explains Eyestone. The prions pass through the wall of the gut and are subsequently absorbed by innervated lymphatic tissues, where they eventually accumulate in the nerves, and then migrate to the spinal cord and brain. The process takes years, Eyestone says, which accounts for the five to seven year incubation period that characterizes both the animal and human forms of the disorder.

While scientists don’t know how to stop the pathogenic process once it gets underway, some, like Eyestone and Huckle, are interested in creating an animal that lacks the genomic architecture to code for the production of normal prions.

"In order to be susceptible to prion disease, the individual has to be able to express the prion," says Eyestone, who is using the same somatic cell transfer technology to clone a cow without normal prions that PPL used to create Dolly the sheep and Mr. Jefferson, the first cloned calf.

Basically, the process involves taking somatic cells harvested from an animal, and replacing the nucleus of that cell with the nucleus of another cell that possesses the desired genetic characteristics, and then implanting that embryo into the animal for a normal gestational development period.

"We know that if you knock out these prion proteins in laboratory mice that there is no apparent negative effect," said Eyestone. "We know that this prion does not appear to be required for normal functions of life. But the mouse has not been that informative to us and we are hoping that the cow will be more so."

The research is funded by the National Institutes of Health. The core objective of the NIH grant is to produce a cow that is genetically incapable of producing prions, and then determine whether or not the viability and function of the animal has been affected by the lack of the prion. Once the cow is cloned in late 2004, the researchers will conduct a number of behavioral and physiological evaluations of the animal.

If efforts to produce a normally functioning cow that lacks the genetic ability to code for the production of prions are successful, the researchers may have identified a strategy for finally containing the risks of this ominous disease.

While the prospects of "cloning" prion free cattle on the scale of America’s 100 million head cattle herd may seen daunting, Eyestone points out that with the widespread use of artificial insemination in modern agriculture, great strides could be made in as little as six or seven generations.

On a smaller scale, sub-populations of prion-free cattle could be produced for use in other tasks such as the production of pharmaceutical compounds that are eventually used in people, thereby eliminating the risk that a drug produced to promote human health and well-being might accidentally cause the deadly neurological condition.

Jeff Douglas | EurekAlert!
Further information:
http://www.technews.vt.edu/

More articles from Agricultural and Forestry Science:

nachricht Researchers discover natural product that could lead to new class of commercial herbicide
16.07.2018 | UCLA Samueli School of Engineering

nachricht Advance warning system via cell phone app: Avoiding extreme weather damage in agriculture
12.07.2018 | Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>