Viriods and prions, Biology

Assignment Help:

Viriods and Prions

Viroids 

      In 1971, T.O.Diener reported that the  spinde tuber disease of potato causing gnarling and cracking of the tuber, is caused by multiplication of a pathogen much smaller than viruses and present in tuber cells themselves, This pathogen found to be a free short and circular RNA strand of about 300nucleotides. Diener  named it viroid. It was found that viroids are infectious because, after multiplying  in a plant cell, these disperse in the tissue and invade new cells. About a dozen plant diseases have since been shown to be caused by viroids.it is also possible that the causative agents of some more plant and animals diseases turn out to be viroides.

Prions

While searching for the cause of a mental disease kuru widespread in a tribe of New Guinea, D,C Gajdusek(1968) discovered that the disease is caused  by a slow virus infection. He shared the 1976 Nobel Prize this work. Later he suspected that other neurological disorders. Like mad cow disease in cows and human dementia and Parkinson disease might also be of this  category, Prisoner (1985) speculated that Creulzfeldt Jacob disease extremely   minute (4-6 nm in diameter ) protein particles which are coded by the genome of certain brain cells, and act as infectious pathogens, These particles have been named prions.


Related Discussions:- Viriods and prions

Define nutritional management of eating disorders, Define Nutritional Manag...

Define Nutritional Management of Eating Disorders? In the last unit, we focused on weight management. It is important to understand that the problems associated with too much d

Deforestation - degradation of ecosystem, Deforestation - Degradation of Ec...

Deforestation - Degradation of Ecosystem The deforestation is a broad term. It means the removal/destruction of the forest cover or the vegetation of an area. It includes repe

How are the male gametes of gymnosperms formed, Q. How are the male gametes...

Q. How are the male gametes of gymnosperms formed? What is the relationship between the pollen grains and the concept of alternation of generations? In the male strobiles (cone

Ecotone - nature and structure of community, Ecotone - Nature and Structure...

Ecotone - Nature and Structure of Community The zone of vegetation separating two different types of communities is called ecotone. It is also known as a transition zone. The

Diagnosis, D i a g no s i s Diagnosis, the key for successful ma...

D i a g no s i s Diagnosis, the key for successful management of the disease problem, refers to identification of the cause of a disease. The process of diagnosis requir

Quantitative real-time pcr, 1. You are given a pair of primers that has bee...

1. You are given a pair of primers that has been shown amplify a 125 bp DNA of interest specifically by a end point PCR- as there was only one PCR product with a size of 125 bp det

Ratios of different samples of nucleic acid, Ratios of the bases in differe...

Ratios of the bases in different samples of nucleic acid yielded the following results: a.  A + C    =   0.6         b.     A  +  C    =  1            c.       A  + G    =  1.2

What is passive transport, What is Passive Transport? Passive Transpor...

What is Passive Transport? Passive Transport :  Specialized proteins called permeases also move specific substances across the cell membrane in a process called carrier transp

How to determines the actual availability of nutrients, How to determines t...

How to determines the actual availability of nutrients The amount of a particular nutrient determined analytically does not necessarily represent what is available but is merel

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd