Changes

==Description==

==Description==

 

Coronaviruses are positive RNA viruses with a diameter of approximately 80-160 nm. The name itself derives from the visual image of individual virus cells as seen by an electron microscope; these cells have a spiky appearance similar to the corona of the sun. This aspect is represented by the glycoprotein that crosses the viral envelope, reaching the protein "coat", called protein S, with hemagglutination and melting properties. The virus structure is more or less typical of coated viruses, therefore it has a helicoidal symmetry nucleocapsid and a pericapsid consisting of a double phospholipid layer of cellular origin; between these two layers, there is a protein coat consisting of the M protein (matrix or matrix). In the nucleocapsid is found the genome consisting of an ssRNA + (a single RNA strand with positive polarity) of 27-30 kilobases which codes for 7 viral proteins and is associated with the protein N.

Coronaviruses are positive RNA viruses with a diameter of approximately 80-160 nm. The name itself derives from the visual image of individual virus cells as seen by an electron microscope; these cells have a spiky appearance similar to the corona of the sun. This aspect is represented by the glycoprotein that crosses the viral envelope, reaching the protein "coat", called protein S, with hemagglutination and melting properties. The virus structure is more or less typical of coated viruses, therefore it has a helicoidal symmetry nucleocapsid and a pericapsid consisting of a double phospholipid layer of cellular origin; between these two layers, there is a protein coat consisting of the M protein (matrix or matrix). In the nucleocapsid is found the genome consisting of an ssRNA + (a single RNA strand with positive polarity) of 27-30 kilobases which codes for 7 viral proteins and is associated with the protein N.

Coronaviruses attach to the cell membrane of the target cells thanks to their S proteins that interact with the aminopeptidase N of the membrane; some coronaviruses can bind neuraminic N-acetyl acid thanks to the expression of E3 glycoprotein.  It is not clear whether cell penetration is performed by fusion of the pericapsid with the plasma membrane or by endocytosis.  Inside the cytoplasm of the cell, the coronavirus releases its positive single-stranded RNA which attaches itself to the ribosomes where it is translated.  The translation involves the production of an RNA-dependent RNA-polymerase (L protein) which transcribes a single negative-stranded RNA from which it is then possible to obtain new positive-stranded RNAs of the coronavirus as well as the seven proteins that it encodes.  Protein N is associated with each new positive RNA strand while pericapside proteins are integrated into the membrane of the endoplasmic reticulum.  A translocator transfers the new nucleocapsides into the lumen of the endoplasmic reticulum, subsequently from these gemstone vesicles which constitute the new virions that can be released by exocytosis.

Coronaviruses attach to the cell membrane of the target cells thanks to their S proteins that interact with the aminopeptidase N of the membrane; some coronaviruses can bind neuraminic N-acetyl acid thanks to the expression of E3 glycoprotein.  It is not clear whether cell penetration is performed by fusion of the pericapsid with the plasma membrane or by endocytosis.  Inside the cytoplasm of the cell, the coronavirus releases its positive single-stranded RNA which attaches itself to the ribosomes where it is translated.  The translation involves the production of an RNA-dependent RNA-polymerase (L protein) which transcribes a single negative-stranded RNA from which it is then possible to obtain new positive-stranded RNAs of the coronavirus as well as the seven proteins that it encodes.  Protein N is associated with each new positive RNA strand while pericapside proteins are integrated into the membrane of the endoplasmic reticulum.  A translocator transfers the new nucleocapsides into the lumen of the endoplasmic reticulum, subsequently from these gemstone vesicles which constitute the new virions that can be released by exocytosis.

 

Coronaviruses are believed to cause a significant percentage of all common colds in adults and children.  The most common symptoms are fever and acute adenoiditis with higher incidence during the winter and early spring.  In many cases coronaviruses can cause pneumonia, direct viral pneumonia, or secondary bacterial pneumonia; they can also lead to the development of bronchitis, direct viral bronchitis, or secondary bacterial bronchitis.  The human coronavirus discovered in 2003, SARS-CoV, causes severe acute respiratory syndrome (SARS), has unique pathogenesis because it causes upper and lowers respiratory tract infections.  

Coronaviruses are believed to cause a significant percentage of all common colds in adults and children.  The most common symptoms are fever and acute adenoiditis with higher incidence during the winter and early spring.  In many cases coronaviruses can cause pneumonia, direct viral pneumonia, or secondary bacterial pneumonia; they can also lead to the development of bronchitis, direct viral bronchitis, or secondary bacterial bronchitis.  The human coronavirus discovered in 2003, SARS-CoV, causes severe acute respiratory syndrome (SARS), has unique pathogenesis because it causes upper and lowers respiratory tract infections.