The document discusses prions, infectious protein particles that cause various diseases in humans and animals, such as Creutzfeldt-Jakob disease and mad cow disease, and are characterized by their inability to contain nucleic acid. It covers their structure, transmission methods, symptoms, and the lack of effective treatments, emphasizing the importance of sterilization to prevent spread. Additionally, the document notes the historical context of prion research and provides references for further reading.

1. Department of Microbiology
Midnapore College (Autonomous)
Seminar 2017-2018
Made By : Sourav Pan

2. Contant
 Introduction
 Structure
 Difference from Simple Protein
 Diseases
 Symptoms
 Replicati0n
 Transmission
 Difference from bacteria and virus
 Diagnosisi
 Treatment
 Preventation

3. Introduction
Pronounced“pree-on“.Prions are the infectious proteinous
particle without nucleic acid which cause disease in humans
and animals,
Prions composed of the prion protein (PrP) are
believed to be the cause of transmissible spongiform
encephalopathies (TSEs) among other diseases.
In 1960 two researches found two type of diseases
which were Scrapie and Mad Cow Diseases ,after research
they found an interesting information about these diseases
that these diseases are not caused by any Bacteria or Virus,
Hence this diseases are caused by a Misfold Protein which is
called prion.

4. In 1982, Stanley B. Prusiner first coined these
disease causing agent as a prion.
for research on prion protein he got Nobel prize
in 1997,accroding to Prusiner Prions are the ‘Infectious,
Portentous particles which devoid nucliec acid’

5. Structure
 Prions are consist of PrPSC Proteins(Here “PrP” means
‘Prion Protein’ and “sc” means “scrapie”)it is a abnormal
protein.
 Prions are don’t contain any Nucleic Acid(RNA & DNA).
 They are not effected by the UV ray, heat, enzyme.
 Normal prions are contain about 200-250 amino acids
twisted into three telephone chord-likes coils known as
helices, with tail of more amino acids.
 They are 100 times smaller then viruses.
 Prion proteins are misfold protein

6. Difference from Simple Protein
Simple Protein Prion Protein
 There amino acids are show
alpha helix structure.
 This Proteins are structurally
well-defined
 There amino acids show beta
helix structure.
 They are structurally
abnormal or misfolded
protein.

8. Diseases
Prions mainly infect animals and humans, they cause
several type of diseases they are-
In Human : Creutzfeldt-Jakob disease (CJD),
Kuru

9. Diseases
In animal: Scrapie, Bovine spongiform
encephalopathy (BSE) or mad Cow Diseases.

10. Symptoms
 Rapidly developing dementia
 Difficulty walking and changes in gait
 Muscle stiffness
 Confusion
 Weakness
 Difficulty speaking
 Paralysis and death

11. Replication
 After injection inside the host cell prion proteins
(PrPsc) are catalyze the normal proteins(PrPc) to
transform into infectious prion protein.
 After transformation this newly formed prion proteins
catalyze more simple protein into infectious prion
proteins(PrPsc).

13. Transmission
 Prions are transmitted through the contaminated food
particles.
 Prions are transmitted into human by the eating of
beef of infected cow.
 Prions are transmitted through the contaminated
medical instrument.
 They are transmitted while transplant of infected
organs.

14. Difference From Bacteria and Virus
 Prion does not contain any nucleic acid (DNA &
RNA).
 They are extremely resistant in heat and Chemical.
 They cannot mutate .

15. Diagnosis
 Prion diseases are confirmed by taking a sample of
brain tissue during a biopsy or after death.
 There are present several type of test for diagnosis
of prion protein such as - MRI (magnetic resonance
imaging) scans of the brain, Samples of fluid from
the spinal cord, Blood tests etc.

16. Treatment
 No effective medical treatment is known. Prion
diseases can't be cured, it is a fatal diseases , but
certain medicines may help slow their progress.

17. Preventation
Properly cleaning and sterilizing medical
equipment may prevent the spread of
the disease. If you have or may have
CJD, do not donate organs or tissue.
Newer regulations that govern the
handling and feeding of cows may help
prevent the spread of prion diseases.

18. References
 https://www.hopkinsmedicine.org/healthlibrary/cond
itions/nervous_system_disorders/prion_diseases_134,5
6
 https://www.evolvingsciences.com/Prions.html
 https://www.sciencealert.com/scientists-might-
finally-understand-how-prions-become-so-dangerous
 https://en.m.wikipedia.org/wiki/Prion