Prions are infectious agents that are composed of misfolded protein aggregates called PrP, lacking nucleic acid. They can cause fatal neurodegenerative diseases in humans and animals by converting normal PrP proteins into additional misfolded prions. Common prion diseases include Creutzfeldt-Jakob disease in humans, mad cow disease in cattle, and scrapie in sheep. Prions are highly resistant to sterilization by heat, chemicals, radiation, and are difficult to inactivate.

3. What are PRIONS???
•Infectious agent
•Composed of single sialoglycoproteins
called PrP 27-30
•No nucleic acid
Mass of 27000-30000Da
•145 amino acids
•Carboxyl terminus contains
phosphotidylionisitol glycolipids whose
components are ethanol,phosphate,
myoinositol and stearic acid.

5. Fig(a) and (b)
:Microscopic "holes"
are characteristic in
prion-affected tissue
sections, causing the
tissue to develop a
"spongy" architecture

6.  Cattle -Bovine spongiform encephalopathy (BSE)
or mad cow disease.
 Sheep and goat- scrapie
Humans-
1. Creutzfeldt–Jakob disease (CJD)
2. Fatal familial insomnia (FFI)
3. Kuru. etc

9.  The first symptom of CJD is rapidly
progressive dementia, leading to memory loss,
and hallucinations.
 Physical problems such as
 Stammering.
 jerky movements.
 Irritation over no issues.
 The disease has also been shown to result from
use of human growth hormone obtained from
the pituitary glands of persons who died from
Creutzfeldt–Jakob Disease.

10. •1730’s found in English sheep
•1950-kuru
•1960’s-transmittance nature
•1980’s- CJD
•1982- Dr. Stanley Prusnier coins
the term prion.
•1990s- mad cow disease
•2005- new variant of CJD from
beef.
History of prion

11.  Alcohol
 ACID
 STANDARD AUTOCLAVE
METHODS.
 BOILING
 The contaminated soil is carefully
scooped up and put through a
multistage incinerator that reaches
up to 1200 -2000degrees F and it is
further treated.

12. VIROIDS

13.  Viroids are plant pathogens.
 Viroids were discovered,
initially characterized, and
named by Theodor Otto
Diener, plant pathologist at the
Agricultural Research Service
in Maryland, in 1971.
 246-469 nucleotides
 The first viroid to be identified
was Potato spindle tuber
viroid (PSTVd). Some 33
species have been identified.

14.  Viriods multiply inside the nucleus of infected
plant cell by “rolling circle” mechanism, using
the host enzymes.
 Produce a long monomeric strand of RNA
which are cut into monomers ,each monomers
then join to form an individual circular viriod.
 After replication , the progeny RNAs move to
neighbouring healthy cells though the
connecting plasmodesmata or distinct parts of
the plants through phloem.

15.  Potato spindle tuber
disease.
 1st viroid to be identified.
 Natural hosts is potatoes
and tomatoes
 All potatoes and tomatoes
are susceptible to PSTVd
and there is no form of
natural resistance.

16.  Coconut cadang-cadang
viroid (CCCVd)
 Every year one million
coconut palms are killed
by CCCVd and over 30
million coconut palms
have been killed since
Cadang-cadang has been
discovered.

17.  Google scholars.org.in
 National Institutes of Health. (2010). NINDS
Transmissible Spongiform Encephalopathies
Information.
 Cell and molecular biology by Gerald karp.
 Boundless. “Prions.” Boundless Microbiology.
 McGraw hill animations
 Wikipedia
 http://www.eppo.org/QUARANTINE/virus/Cocon
ut_cadang_cadang_viroid/CCCVD0_ds.pdf
 Haseloff, J.; Mohamed, N.A.; Symons, R.H.
(1982) Viroid RNAs of cadang-cadang disease of coconuts.
Nature 299, 316-321.