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

Chemical substances that compose the plasma membrane, What are the chemical...

What are the chemical substances that compose the plasma membrane? Ans) The major constituents of the plasma membrane are phospholipids, proteins and carbohydrates. The phosphol

Can you explain ventricular tachycardia, Q. Can you explain Ventricular Tac...

Q. Can you explain Ventricular Tachycardia? The term is usually reserved for at least four or more beats and modified by the term non sustained. Short runs of non-sustained VT

Define aerobic exercise or aerobic energy system, Define Aerobic Exercise o...

Define Aerobic Exercise or Aerobic Energy System? To produce necessary energy, the body uses an aerobic pathway and an anaerobic pathway. Exercise that relies heavily on oxygen

Which of groups is not ionizable, Which of the following groups is NOT ioni...

Which of the following groups is NOT ionizable? Select one: a. Guanidinium b. Imidazole c. Phosphoryl d. Amine e. Aldehyde

#green algae, #what characteristics of green algae that led to biologists c...

#what characteristics of green algae that led to biologists considered it as a plant?

Etiologic factor of ulcerative colitis, Q. Etiologic factor of ulcerative c...

Q. Etiologic factor of ulcerative colitis? No single etiologic factor has been identified although genetic auto-immune factors are thought to be involved. Although exacerbation

Which type of gamete do the male respectively produce, Concerning the sex c...

Concerning the sex chromosomes of the XY system which type of gamete do the male and the female individuals respectively produce? The individual of the male sex is XY so he for

Common causes related with angina pectoris, Q. Common causes related with a...

Q. Common causes related with angina pectoris? • The usual cause of angina is the narrowing of the major coronary artery due to atherosclerosis. • Systemic hypertension inc

Skeletons of radiolarians, Skeletons of radiolarians The skeletons of ...

Skeletons of radiolarians The skeletons of radiolarians and foraminiferans form a primary constituent of ocean bottoms where they form 30% or more of the sediment. It is calle

Culture negative endocarditis, In patients who have not received prior anti...

In patients who have not received prior antibiotics and who will ultimately have blood culture positive endocarditis, it is likely that 95 - 100 per cent of all cultures obtained w

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