Prusiner's Prion Hypothesis - Bio-Medicine

The Virion Hypothesis states that TSEs are caused by a replicable informational molecule (which is likely to be a nucleic acid) bound to PrP. Many TSEs, including Scrapie and BSE, show strains with specific and distinct biological properties, a feature which supporters of the Virion hypothesis feel is not explained by prions. The presence of a nucleic acid bound to the protein would explain the strains observed. It has also been shown that TSEs including BSE retain their host-specific properties after passage through many different species. [42]

The bony structures of the skull itself can cause contusions in surprising places.

NAEGLERIA, acquired byhealthy people who swim in stagnant ponds, enters the CSF via the nose, and causes necrosis of the olfactory bulbs and nearby frontal and temporal lobes ("primary amebic meningoencephalitis").

Researchers have isolated infectious prion proteins ..

This may be under the scalp, or in the neck; the latter may be a surprisingcause of airway obstruction (J.

Was a particular conformation of bovine PrPSc selected for heat resistance during the rendering process and then reselectedmultiple times as cattle infected by ingesting prion-contaminatedMBM were slaughtered and their offal rendered into more MBM? Recentstudies of PrPSc from the brains of patients who died of vCJD show a pattern ofPrP glycoforms different from those found for sporadic or iatrogenicCJD (). However, the utility of measuring PrP glycoforms isquestionable in trying to relate BSE to vCJD () because PrPSc is formed after the protein is glycosylated () and enzymaticdeglycosylation of PrPSc requires denaturation (). Alternatively, it may be possibleto establish a relation between the conformations of PrPSc from cattle with BSE and those from humans with vCJD by usingTg mice, as was done for strains generated in the brains of patientswith FFI or fCJD ().

STOCKHOLM, Sweden (Reuter) - Stanley Prusiner, a U.S

Our results provide a plausible mechanism for explaining diversity in a pathogen that lacks nucleic acid; the biological properties of prion strains seem to be encrypted in the conformation of PrP-Sc. Because prion strains produce different disease phenotypes, such findings raise the possibility that deviations in the phenotypes of other degenerative disorders may also reflect conformational variants in pathologic proteins. Variations in the conformation of PrP-Sc are reproduced through templating of the PrP-Sc in the inoculum onto the substrate PrP-C. Deciphering the molecular events by which the conformation of one protein is imparted to another and the mechanism responsible for the apparently high degree of fidelity associated with this process should be of considerable interest. Indeed, the foregoing data violate the widely and long-held idea that amino acid sequences are the sole determinants of the tertiary structures of biologically active proteins ().

Prion Diseases and the BSE Crisis - Science | AAAS

Prusiner's pioneering work has opened new avenues for understanding thepathogenesis of more common dementia-type illnesses. For example, thereare indications that Alzheimer's disease is caused when certain, non-prion,proteins undergo a conformational change that leads to the formation ofharmful deposits or plaques in the brain. Prusiner's work has also establisheda theoretical basis for the treatment of prion diseases. It may be possibleto develop pharmacological agents that prevent the conversion of harmlessnormal prion proteins to the disease-causing prion conformation.

Prusiner Bovine spongiform encephalopathy (BSE ..

Bovine spongiform encephalopathy (BSE) and human Creutzfeldt-Jakob disease (CJD) are among the most notable central nervoussystem degenerative disorders caused by prions. CJD may presentas a sporadic, genetic, or infectious illness. Prions are transmissibleparticles that are devoid of nucleic acid and seem to be composedexclusively of a modified protein (PrPSc). The normal, cellular prion protein (PrPC) is converted into PrPSc through a posttranslational process during which it acquiresa high -sheet content. It is thought that BSE is a result ofcannibalism in which faulty industrial practices produced prion-contaminatedfeed for cattle. There is now considerable concern that bovineprions may have been passed to humans, resulting in a new formof CJD.