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

Verify that the transforming agent in a bacteriophage, Which of the followi...

Which of the following experimental steps permitted Hershey and Chase to verify that the transforming agent in a bacteriophage is DNA as well? A. Phage particles were mixed wit

What are important terms in accommodation and convergence, What are importa...

What are important terms in accommodation and convergence? Accommodation and Convergence In this section some important terms are included: a. How a person is able to foc

Define factors that are involved in the regulation, Describe the factors th...

Describe the factors that are involved in the regulation of respiration in a child who decides to hold his/her breath for as long as possible.

Explain differences between thrombus and embolus, Explain the differences b...

Explain the differences between a thrombus and an embolus. Include predisposing factors, mechanism of occurrence, treatment, and methods of detection with medical imaging, if any.

Fertilizers and fertilizer management, Fertilizers and Fertilizer Managemen...

Fertilizers and Fertilizer Management Fertilizers, in a broad sense, include all materials that are added to soils to supply certain elements essential to the growth of plants

What is a closed circulatory system, Q. Define a closed circulatory system?...

Q. Define a closed circulatory system? A closed circulatory system is one in which blood circulates only inside blood vessels for this reason the blood pressure is higher in so

Apex locator in retreatment cases-endodontics principles, Apex locator in r...

Apex locator in retreatment cases: -    Electronic apex locators may give misread for working length when gutta-percha is initially being removed. -    Due to that file beging

Grouping of stem cells-totipotent scs, Grouping of Stem Cells: The rang...

Grouping of Stem Cells: The range of differentiation “Potency” is an important property of Stem cells & serves as the basis for classifying cells as : Totipotent SCs -capa

Phylum annelida, sanguivarous mode of feeding in annelida

sanguivarous mode of feeding in annelida

Continuous wave doppler, In continuous wave Doppler, the transducer has tw...

In continuous wave Doppler, the transducer has two Doppler crystals, one to constantly transmit and one to continuously receive. As a result of this continuous mode of tra

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