Structure/function of the flu
What are the H and N in the flu? What are their functions for the virus?
Most recent threat is H5N1. What does this name imply?
Shannon Holfoth, Rachel Francis, Caitlin Moreland, Teresa Castiglione, and Katie VanUden write: H5N1 is the avian bird flu. It does not affect humans but puts worries that it is changing or shifting and may soon infect humans. The H stands for Hemagglutinin which is a type of protein on the virus which attaches to the infected cells. There are currently 16 different type of H variants. The N stands for Neuraminidase which is also a protein found on the virus. This protein helps in the efficiency of releasing the virus into the cell. There are 9 known N variants.
Khadeeja & Sara write: The H in the flu is the protein haemagglutinin and the N in the flu is the protein neuraminidase . The function of H for the virus is to let the virus grab onto cells and infect them. The function of N for the virus is to let the virus get out of cells that it has infected. H5N1 is a strand of the disease, avian influenza and is a type of influenza virulent in birds.
Rob Schnitzius writes: The H and the N in the flu are glycoprotein molecules. The H being hemagglutinin and the N being neuraminidase. When the flu consists of N and H, it is considered type A. Influenza type A is mostly found in animals and not humans, although it is able to cross the species barrier if the virus undergoes genetic re-assortment.
Hemagglutinin allows the virus to infect the outside as well as the inside of cells of the upper respiratory tract. It does this by attaching itself (adsorption) to cells through receptors on the cell containing sialic acid, it then blends the cell membrane with the membrane of the virus, which lets the RNA of the virus get inside the cell where it multiplies inside of the cell to make thousands of new virus particles. After this viral replication, the progeny virions must be released from the cell to repeat the cell cycle of infection.
Neuraminidase (NA) cleaves the terminal sialic acid receptors from the host cell and other recently made virus particles by division of -glycosidic bonds. This lets the virus escape from the cell in which it grew and spread in the body to infect other cells. The action of NA may also assist viral mobility through the mucus of the respiratory tract.
H5N1 is the Bird Flu, or Avian Virus. It is a type A influenza virus that occurs mainly in birds, but can also affect humans due to genetic re-assortment. This virus carries a pandemic threat. The threat is due to the high mortality rate and virulence to date, its endemic presence, large and increasing biological host reservoir, and its significant ongoing mutations. The H5 in H5N1 stands for the fifth of several known types of the protein hemagglutinin, while the N1 stands for the first of several known types of the protein neuraminidase.