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 A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>