HMB202H1 Lecture Notes - Lecture 4: Endosome, Lysis, Cell Membrane
Document Summary
Whenever the bacterium reproduces, the prophage is also copied. Endotoxins are only released when the bacteria cell dies or during cell division. In addition to being classified which type of cells they infect (neurotoxin, enterotoxin, cytotoxin), they can also be classified based on their structure/function: a-b toxins, toxins that disrupt membranes, and superantigens. A-b toxins the b domain binds to a specific receptor (usually a carbohydrate) on the host cell. The entire exotoxin is then brought inside through endocytosis. Once inside the endosome, the b domain creates a pore in the endosome which allows the a domain to escape into the cytoplasm where it causes its effects (ex. inhibiting protein synthesis or interfering with host cytoskeleton). Membrane disrupting toxins they do not enter the cell but instead form pores in the host plasma membrane. Superantigens these exotoxins stimulate an excessive immune response.
