Featured Research

from universities, journals, and other organizations

Intestinal Lymphatic Tissue Important For The Absorption And Spread Of The Scrapie Prion

Date:
January 17, 2009
Source:
Norwegian School of Veterinary Science
Summary:
Scrapie is a transmissible, degenerative and ultimately fatal disease of the nervous system of sheep. The cause of the disease is a prion protein, and absorption from the intestine is assumed to be the natural route of infection. Lymphatic tissue associated with the intestine is important for the early accumulation of prion protein and its subsequent spread to the central nervous system.

Ileal Peyer's patch of sheep. The section is stained with haematoxylin.
Credit: Lars Austbø, NVH

Scrapie is a transmissible, degenerative and ultimately fatal disease of the nervous system of sheep. The cause of the disease is a prion protein, and absorption from the intestine is assumed to be the natural route of infection. Lymphatic tissue associated with the intestine is important for the early accumulation of prion protein and its subsequent spread to the central nervous system.

Transmissible prion diseases occur in both animals and man, two well-known ones being mad cow disease of cattle and Creutzfeldt Jacobs disease of man. These diseases produce symptoms in the central nervous system, with classical scrapie being characterised by intense itching with subsequent loss of wool, smacking of the lips, abnormal gait, and eventually collapse.

Protein molecules may show different properties when their structures become altered, for example, proteins in egg white are hardened by heat treatment. The assumed cause of prion diseases is that the structure of the normal prion protein (called PrPC) becomes altered. The abnormal, disease-associated form of the prion protein (called PrPSc) is assumed to be the infectious agent.

Infection most likely occurs across the intestine, and one first sees an accumulation of PrPSc in the lymphatic tissue associated with the intestine, especially in areas of the small intestine called Peyer's patches. The infection then spreads to the central nervous system and the brain, where, in the final stages of the disease, one sees an accumulation of PrPSc and also structural changes such as sponge-like "holes" in the brain mass.

We understand as yet very little of just how the infectious PrP is absorbed from the intestine. It is assumed that infection requires the presence of the normal form of the protein PrP, and it is known that the gene for PrP is active in a series of different types of cells and tissues.

For his doctorate, Lars Austbø investigated the activity of the gene for prion protein (PrP mRNA) by looking at where in the intestinal tissue it is formed and in what quantity. He also identified other genes of possible significance for the early phase of scrapie.

Austbø used advanced gene technology and molecular biology to study both prion gene activity (PrP mRNA) and the presence of the protein PrPC in the Payer's patches of the small intestine and in the spleen - two organs where lymphoreticular tissue is assumed to be important for the absorption of the infective substance (PrPSc) and its spread to the brain.

Austbø and his colleagues have compiled new knowledge of the tissues that the PrPC protein and its mRNA is expressed in and the degree to which the gene is active. In addition, the study has shown that accumulation of the disease-related prion protein (PrPSc) is not necessarily associated with high levels of the normal prion protein. This conflicts with earlier assumptions and may force a re-evaluation of earlier theories on the absorption and distribution of the disease-related prion protein.

In addition, Lars Austbø worked with the identification of other genes that may play a role in the development of scrapie. Many genes contribute to, or are affected by, any disease progression. By mapping such genes, one can gain a better impression of the processes that are initiated and thereby a better understanding of disease development.

Cand. scient. Lars Austbø defended his Ph. D. thesis, entitled "Studies on gene expression during the lymphoreticular phase of scrapie in sheep", on June 26, 2008. The work for the thesis was done at the Department of Basal Sciences and Aquatic Medicine, the Norwegian School of Veterinary Science.


Story Source:

The above story is based on materials provided by Norwegian School of Veterinary Science. Note: Materials may be edited for content and length.


Cite This Page:

Norwegian School of Veterinary Science. "Intestinal Lymphatic Tissue Important For The Absorption And Spread Of The Scrapie Prion." ScienceDaily. ScienceDaily, 17 January 2009. <www.sciencedaily.com/releases/2009/01/090109095115.htm>.
Norwegian School of Veterinary Science. (2009, January 17). Intestinal Lymphatic Tissue Important For The Absorption And Spread Of The Scrapie Prion. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2009/01/090109095115.htm
Norwegian School of Veterinary Science. "Intestinal Lymphatic Tissue Important For The Absorption And Spread Of The Scrapie Prion." ScienceDaily. www.sciencedaily.com/releases/2009/01/090109095115.htm (accessed September 23, 2014).

Share This



More Plants & Animals News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cat Lovers Flock to Los Angeles

Cat Lovers Flock to Los Angeles

AFP (Sep. 22, 2014) — The best funny internet cat videos are honoured at LA's Feline Film Festival. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com
Washed-Up 'Alien Hairballs' Are Actually Algae

Washed-Up 'Alien Hairballs' Are Actually Algae

Newsy (Sep. 22, 2014) — Green balls of algae washed up on Sydney, Australia's Dee Why Beach. Video provided by Newsy
Powered by NewsLook.com
Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) — The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins