PRIONS AND VIROIDS , Diseases caused by Prions General properties , REPLICATION OF VIROIDS , viorids is 2 types

1. PADMASHREE INSTITUTE OF
MANEGMENTAND SCIENCE.
Seminar topic on;
 PRIONS AND VIROIDS.
Presented by;
Shylesh murthy I .A
2nd yr Msc biotechnology
PIMS

2. Prions
 Stannelly B pruisher American biochemist and Neuro
coslt discovered Prions .
 He got Nobel prize in 1977
 Mainly infect the animals calf, cow, sheep ,human
beings etc..
 These Prions effect brain cell .
 Prions are infectious agent differ from virus .

3.  A/c to stannely Prions are infectious self
reproducing pathogen mainly composed of
protein
 These Prions are very difficult to discover
 In this Prions the genetic material is DNA

4. Diseases caused by Prions
 Scarpie disease in sheep
 Transmissible mink encephalopathy(TMF)
 Chronic wasting diseases in male
 Cows causes bowine spongy form
encephalopathy (Mad cow disease)

6. Causes of Prions diseases
 CANNABOLISM eating of 1 human by
another human .
 People in New Guinea used to suffer from kuru,
which they got from eating the brains of their
enemies
 These diseases can spread due to use of
product of one animal to feed another
 Mechanism of these spread of diseases is not
fully understand

7. Viroids
 They are smaller than viruses
 It was first time discover in potato plant
Diseases called potato spindle tubular viroids
(pstv)
 T.O Diener and W.B Raymer

8. General properties
 Viriods are phatogens invivo as encapsulated in
Rna
 Like viruses don’t have specific structures .
 Rna is genetic material of viroids
 These have low Molecular weight
 Like viruses they can replicate(like no media
required , it depend on any factors)
 They will effect to plants
 Ex; cucumber plant

10. viorids is 2 types ;
1. Pospi Viroidae
2. Avsun viroidae
REPLICATION OF VIROIDS ;-
Till now no coviency replication are not there
 Pospi Viroidae ,Avsun viroidae replication inside the nucleus of host
 2 possibilities are Rna dependent , Dna dependent type of replication
 Rna polymerase help in replication

11. Diseases
 Causes stunting of plants, shelling of bark
 May result in little yield loss

13. .Thankyou ……….