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

Botany., the evolution of gamatophyte in pteridophyte

the evolution of gamatophyte in pteridophyte

Define the food and nutrition security, Define the Food and Nutrition Secur...

Define the Food and Nutrition Security? In the previous section, we learnt about the trends in production of food grains in the country and their relationship to population gro

Silver point extended below canal orifice, Silver point extended below cana...

Silver point extended below canal orifice -    Ultra-sonic tip -    Microtube tape: The post removal system (PRS) Trephine bur Masserann kit - Do trimming by

Explain cooperative behaviours of social animal group, Explain Cooperative ...

Explain Cooperative behaviours of social animal group Group living, specialist roles, eg bees, ants Altruism, eg social insects, meerkats Group defence, eg social

Functions of ovary, Functions of Ovary The ovary of vertebrates perfor...

Functions of Ovary The ovary of vertebrates performs the following functions:   Production of eggs, Synthesis of hormones needed for the chemical coordination of repr

What are the uses of whey protein concentrates, What are the uses of whey p...

What are the uses of whey protein concentrates? Whey protein concentrates are used extensively in the manufacture of baked goods, where they increase the effectiveness of short

What is calvin cycle, What is Calvin Cycle? The dark reactions of photo...

What is Calvin Cycle? The dark reactions of photosynthesis are also known as the Calvin cycle. This process synthesizes glucose molecules using carbon dioxide from the atmosphe

Meaning of behaviour change communication, Meaning of Behaviour Change Comm...

Meaning of Behaviour Change Communication Now day's very common term used for giving health education to people and for giving information to bring change in behaviour is Behav

What do you mean by pericardium, Q. What do you mean by Pericardium? Pe...

Q. What do you mean by Pericardium? Pericardium is the sac covering the heart. Pericardium consists of two layers-the visceral pericardium (epicardium) and the parietal pericar

How are poriferans characterized, Concerning digestion how are poriferans c...

Concerning digestion how are poriferans characterized? Sponges are dissimilar from other animals since they present only intracellular digestion. They do not have a digestiv

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