Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The protein that makes you mad

21.06.2006
In recent years our feeding habits have been the focus of ongoing polemics. Everybody will remember the "mad cow" crisis when the sales of veal plummeted for fear of contagion, thousands of animals were sacrificed and beef imports, especially from the United Kingdom – the focus of the epidemic – were curtailed.

The origin of the crisis was the feeding of cattle with animal feed that was contaminated by a new pathogenic agent – a prion. These cows, after a long incubation period, died of dementia. The prion entered the human food chain without evident symptoms being observed - the pathogen was able to jump the species gap to humans. This created unprecedented alarm amongst the public at large and gave rise to great interest in these diseases - Transmissible Spongiform Encephalopathies (TSEs) and in the great protagonist of the story, the prion.

Prions are proteins – without DNA – capable of causing rare neurodegenerative diseases, currently without a cure, by means of a novel process different from that of the “classic” virus and bacteria. The prion presents two distinct forms: a “healthy” one present in all animals (PrPc) and another, pathogenic one (PrPsc) which is the causative agent of the ailment. When PrPsc enters a living being, through feeding, it looks for the PrPc as a host and transforms it into a new PrPsc. So, the PrPc disappears and the PrPsc accumulates.

Although the PrPc exists in practically all the tissues of the body, the TSEs only appear in the brain. This is why neurones die and spaces or cavities appear which give rise to the typically “spongy” appearance. What route does the prion follow from the mouth to the brain? This is the great mystery. The first obstacle it encounters is the acidity of the gastric juices, then the action of the enzymes that break up the foods we swallow and then it has to pass through the digestive tract wall. The cells containing the PrPc could be the entry gate but … what cells are they? Are the same in different animal species? Nobody knows.

Answering these questions has been the aim of this thesis and, in order to achieve this objective, we carried out a “sweep” along the digestive tract of rats, primates and of Pyrenean cows – the most affected breed in Navarre. We employed a number of techniques enabling the location of PrPc – using antibodies specifically targeting it. These antibodies, amongst other items, were marked with fluorescent molecules so the positive cells could be subsequently visualised with a microscope.

The results showed that PrPc appears in the endocrine cells that are dispersed throughout the digestive tract. Endocrine cells produce hormones, biochemical messengers that are secreted into the blood and control the correct functioning of the body. This suggests that the conversion of PrPc to PrPsc may occur in these cells and arrive at the brain in the blood. But, in the digestive tract there are dozens of different endocrine cells and not all have PrPc. To identify which ones have and which do not, we detected, simultaneously, the PrPc and another substance, characteristic of each cell type and observed if the marking appeared in the same cells or not. By means of this system we were able to confirm that, curiously, the PrPc appeared in the same cells in all three animal species.

Finally, we also detected PrPc in the nervous system of the wall of the digestive tract. In this case, the disorder may be propagated to the brain through the signals between neurones – the synapses - that link both organs.

Irati Kortabitarte | alfa
Further information:
http://www.basqueresearch.com/berria_irakurri.asp?Gelaxka=1_1&hizk=I&Berri_Kod=988

More articles from Life Sciences:

nachricht Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)

nachricht CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>