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 Kakao in Monokultur verträgt Trockenheit besser als Kakao in Mischsystemen
18.09.2017 | Georg-August-Universität Göttingen

nachricht Ultrasound sensors make forage harvesters more reliable
28.08.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

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: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>