Viruses

potato spindle tuber disease slideshare

potato spindle tuber disease slideshare
  1. What causes potato spindle tuber disease?
  2. What is the genetic material of potato spindle tuber virus?
  3. What is the meaning of Viroids?
  4. Who discovered viroids?
  5. Is Viroids smaller than virus?
  6. Are Virusoids self replicating?
  7. Which disease is caused by Viroids?
  8. What is the difference between viroids and viruses?
  9. Are prions living?
  10. How do Viroids infect?
  11. Which plant virus is Gemini virus?
  12. Who showed that viruses are smaller than bacteria?
  13. How can prions be destroyed?
  14. Do prions have protein?
  15. How do prions infect?
  16. What is the difference between a virus viroid and prion?
  17. Which of the following is a human disease caused by prions?
  18. What does prion mean?
  19. Are viruses viroids and prions living?
  20. Who showed that viruses could be crystallized?
  21. What do all viruses have?

What causes potato spindle tuber disease?

Potato Spindle Tuber Viroid (PSTVd) is an EU listed quarantine pathogen of potatoes which causes stunting of the plant and malformation and cracking of tubers. The main host is potatoes but the disease also affects tomatoes and solanaceous ornamentals.

What is the genetic material of potato spindle tuber virus?

The Potato spindle tuber viroid ("PSTVd") was the first viroid to be identified. PSTVd is a small, single stranded circular RNA molecule closely related to the chrysanthemum stunt viroid.

What is the meaning of Viroids?

Viroid, an infectious particle smaller than any of the known viruses, an agent of certain plant diseases. The particle consists only of an extremely small circular RNA (ribonucleic acid) molecule, lacking the protein coat of a virus. ... Whether viroids occur in animal cells is still uncertain.

Who discovered viroids?

The pathogen is called a viroid by its discoverer, Dr. Theodor 0. Diener, to distinguish it from a virus.

Is Viroids smaller than virus?

Viroids are plant pathogens: small, single-stranded, circular RNA particles that are much simpler than a virus. They do not have a capsid or outer envelope, but, as with viruses, can reproduce only within a host cell. Viroids do not, however, manufacture any proteins.

Are Virusoids self replicating?

A second type of pathogenic RNA that can infect commercially important agricultural crops are the virusoids, which are subviral particles best described as non–self-replicating ssRNAs. The virusoid genomes are small, only 220 to 388 nucleotides long. ...

Which disease is caused by Viroids?

The only human disease known to be caused by a viroid is hepatitis D. This disease was previously ascribed to a defective virus called the delta agent. However, it now is known that the delta agent is a viroid enclosed in a hepatitis B virus capsid.

What is the difference between viroids and viruses?

Viroids are free RNA molecules of low molecular weight without any protein coat while viruses can have either RNA or DNA molecules encapsulated in a protein coat. Viroids are smaller in size than the viruses. Viroids infect only plants whereas virus infects all types of organisms.

Are prions living?

Prions, however, are not living organisms. Prions are infectious proteins. For unknown reasons, these proteins refold abnormally and cause a domino effect in surrounding proteins which in turn mutate into stable structures. Prions will then cause tissue damage and cell death to surrounding areas.

How do Viroids infect?

Viroids are often transmitted through vegetative propagation of plants, but can also be transmitted during agricultural or horticultural practices in which contaminated instruments are used. Some viroids can be transmitted through seeds and at least one viroid is transmitted by an aphid.

Which plant virus is Gemini virus?

Geminiviruses (family Geminiviridae) are small single-stranded (ss) DNA viruses infecting plants. Their virion morphology is unique in the known viral world – two incomplete T = 1 icosahedra are joined together to form twinned particles. Geminiviruses utilize a rolling-circle mode to replicate their genomes.

Who showed that viruses are smaller than bacteria?

This meant that something even smaller than bacteria was causing the infection. Scientists did not actually see viruses for the first time until the 1930s. That's when the electron microscope was invented. In 1915, English bacteriologist Frederick Twort discovered bacteriophage, the viruses that attack bacteria.

How can prions be destroyed?

To destroy a prion it must be denatured to the point that it can no longer cause normal proteins to misfold. Sustained heat for several hours at extremely high temperatures (900°F and above) will reliably destroy a prion.

Do prions have protein?

Prions are misfolded proteins with the ability to transmit their misfolded shape onto normal variants of the same protein. They characterize several fatal and transmissible neurodegenerative diseases in humans and many other animals.

How do prions infect?

Contaminated food is ingested. Prion infectivity is accumulated in lymphoid tissue. Prions spread throughout the lymphatic tissue and the enteric nervous system, finally reaching the CNS. There they infect the neurons and then are broadcast to other tissues for replication.

What is the difference between a virus viroid and prion?

Viroids are plant pathogens that consist of a very short stretch of circular, single-stranded RNA that does not have a protein coat. They are essentially strands of naked RNA. They are much smaller than viruses. Prions are protein particles that can cause other proteins to form abnormal shapes, which causes disease.

Which of the following is a human disease caused by prions?

The human forms of prion disease are most often the names Creutzfeldt-Jakob disease (CJD), fatal familial insomnia (FFI), Gertsmann-Straussler-Scheinker syndrome (GSS), kuru and variably protease-sensitive prionopathy (VPSPr).

What does prion mean?

The term “prions” refers to abnormal, pathogenic agents that are transmissible and are able to induce abnormal folding of specific normal cellular proteins called prion proteins that are found most abundantly in the brain. The functions of these normal prion proteins are still not completely understood.

Are viruses viroids and prions living?

They can therefore be regarded as living - and virology is indeed a branch of biology. " My understanding is that viruses and viroids (not mentioning prions) are non-living since they are metabolically inactive and unable to reproduce outside a host.

Who showed that viruses could be crystallized?

Tobacco mosaic virus was the first virus to be crystallized. It was done by Wendell Meredith Stanley in 1935. He also showed that TMV remains active even after crystallization. For his work, he was awarded the Nobel Prize in Chemistry in 1946.

What do all viruses have?

All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form, outside the cell, a virus particle is called a virion.

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