Microbial World

Organisms Infectious agents

I Domain B^S^Ta Rua® I Viruses Viroids Prions

Prokaryotes Eukaryotes (unicellular)

Algae Protozoa Fungi Helminths

(unicellular or (unicellular) (unicellular or (multicellular multicellular) multicellular) parasites)

multicellular) parasites)

Protists

Figure 1.10 The Size of a Viroid Compared with a Molecule of DNA from a Virus that Infects Bacteria (T7) The red arrows point to the potato spindle tuber viroids (PSTV); the other arrow points to T7 DNA.

Prions are very unusual agents that are responsible for at least six neurodegenerative diseases in humans and animals; these are always fatal. Prions appear to be only protein, without any nucleic acid (figure 1.11). Although unlikely, it is possible that another agent that is very difficult to isolate might also be involved in causing the neurodegenerative diseases.

Figure 1.11 Prion Prions isolated from the brain of a scrapie-infected hamster. This neurodegenerative disease is caused by a prion.

Was this article helpful?

0 0
Getting Rid Of Warts Forever

Getting Rid Of Warts Forever

All wart sufferers, this is the day to stop the shame. How I Got Rid Of My Warts Forever and How You Can Get Rid Of Warts Naturally In 3 Days. With No Blisters, No Scars, And No Pain Without medications or expensive procedures. All by applying a simple, very natural and unbelievable FREE substance that can be found in almost every household.

Get My Free Ebook


Post a comment