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Until 1970, viruses were thought to be the simplest creatures that could reproduce themselves in nature. In 1971, TO Diener of the United States Department of Agriculture found that the potato root-knuckle disease agent was a small RNA in a circular structure without a specific protein coat. As a result of further studies, such naked RNA fragments were identified in plants with a number of disease-causing plaques and Diener's name viroyites. Although they have such a simple structure, virolytic RNA can self-match and in this case a double helix structure is formed. This self-mapping ensures that the tRNA, rRNA and mRNA tail are more stable.
The viroid genome is very short (about 10 times shorter than the shortest viral chromosome). The largest can contain only 100 amino acids of protein and there is no evidence of the presence of any enzyme or product formed by virolys. Virolyses have enough information to create an RNA polymerase that will only allow them to replicate themselves.
Yes, but how does viroyites cope? The RNA polymerase is found only in the nuclei of eukaryotes, in which case it is believed that a signal sequence in virolyte RNA is transported into and out of the nucleus. Then, the RNA polymerase recognizes a promoter in the DNA of the nucleus, and the virolyte sequence is somewhat similar to the target DNA promoter. This double helix structure of the Viroyites protects them enzymatically and imparts the physical structures described in chapter 11. This structure is necessary for the polymerase binding of regulatory proteins to the promoter region during transcription of the transporter.
In short, virolysses are not capable of forming a protein "message" with the knowledge necessary to reproduce within the complex eukaryotic genetic system, ie they are like a hollow letter envelope stamped with the correct address on it.
Since the discovery of virolyses, the most valid thing we know about them is that they cause disease in very important plants (eg they form tumors in the pathology).
The basis for their pathogenicity is a 40-base region of a small ribosomal RNA of 45-70 nucleotides. Virolyses are believed to bind to rRNA as they concentrate on the nucleus synthesized by the rRNA and thus inhibit the regulation of the ribosomes.
Virolysis is quite common in nature, but it is difficult to be noticed because they do not lyse host cells. For this reason there is very little information about their spread.

Priyonlar

Ivanovsky argued that something similar (a self-replicating protein) could be important in diseases after giving up the bacterial toxin hypothesis in viral events. For example, sheep and goats are responsible for the scrapie's disease, which causes significant damage to the central nervous system. Today it is not known how such an isolated protein agent, called prion, produces more infectious proteins. The effect of two rare neurological diseases in humans is the same group (Crevtzfeldt-Jakob disease and Gerstmann-Strassler syndrome).
A system that leads to the production of an infectious protein by another infected protein may be in the form of producing a new version of itself in the host cell, a precursor product of the protein origin, such as a step catalysis of the digestive enzyme chymotrypsin itself. Scrapie-infected animals also have such a protein that is similar to a product encoded by the exon of the host gene other than two amino acids. This phenomenon, which occurs to catalyze the conversion of the prion polypeptide to a prion version of a normal protein (a receptor found in neural regulation), occurs without allowing the affected cell to bind its normal receptor to its own membrane. There are other possible mechanisms for the movements of the prions, and some researchers believe that the prions have returned to receive nucleic acid after all. In any case, these seem to keep the mystery of the smallest biological beings for a while longer.
Source: poxox.com learn

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