Health Medical Homework Help. HS 320 Purdue Global University Unit 4 Differentiate between Endo and Exotoxins Discussion
Generate 2 responses to original discussion posts, each response must be at least 300 words + 3 references no older than 5 years.
Here is the original DIscussion topic :
Toxins
Differentiate between Endo- and Exotoxins. Using specific examples of bacteria, explain how the toxins they produce contribute to the virulence of those organisms.
POST 1
According to Pommerville, endotoxins are lipopolysaccharides. They are metabolic poisons. They are produced by gram-negative bacteria that are part of the bacterial cell wall and consequently are released on cell disintegration; composed of lipid-polysaccharide-peptide complexes (Pommerville, 2018).
Example of endotoxin: Salmonella Typhi. Virulence factors are clustered in some areas of the chromosome such as adhesion, invasion, and toxin genes. A protein that permits non-phagocytic cells is also produced and excreted by the bacterium, where it is capable of intracellular living (Al-Khafaji, Al-Bayati, & Al-Dahmoshi, 2021).
Exotoxins are bacterial metabolic poisons. They are composed of protein that is released to the environment. When an exotoxin enters the human body, it can affect various organs and systems (Pommerville, 2018).
An example of an exotoxin is whooping cough. I chose this example because I am allergic to the whooping cough vaccine. According to Carbonetti, pertussis toxin is a secreted protein exotoxin. It is an important virulence factor produced exclusively by B. pertussis. Pertussis toxin is transported across the bacterial outer membrane by a type IV secretion system (Carbonetti, 2010).
One difference between endo- and exotoxins: Endotoxins are produced by Gram-negative bacteria, while exotoxins are secreted by both Gram-negative and Gram-positive bacteria.
Class, you know how some people get faint at the sight of blood? Well, this happens to me when I think of toxins being released. I don’t know why but it makes me feel woozy… ?
References
Al-Khafaji, N. S. K., Al-Bayati, A. M. K., & Al-Dahmoshi, H. O. M. (2021, January 8). Virulence factors of Salmonella typhi. Retrieved from https://www.intechopen.com/online-first/74829
Carbonetti, N. H. (2010). Pertussis toxin and adenylate cyclase toxin: key virulence factors of Bordetella pertussis and cell biology tools. Future microbiology, 5(3), 455–469. https://doi.org/10.2217/fmb.09.133
Pommerville, J. (2018). Fundamentals of microbiology (11th ed.). Jones & Bartlett Learning.
POST 2
Exotoxins are produced inside of some bacteria as part of the growth and metabolism then they are released into the surrounding media. Endotoxins are part of the outer portion of cell wall of gram-negative bacterial. Endotoxins are released during bacterial multiplication and when gram-negative bacteria die the cell walls undergo lysis (Tortora, et al., 2016).
There are a lot of differences between exotoxins and endotoxins. Bacterial source of exotoxins is mostly from gram-positive bacteria while bacterial source of endotoxins is from gram-negative bacteria. Exotoxins are metabolic product of growing cell and endotoxins present in lipopolysaccharide of outer membrane of cell wall and released with destruction of cell or during cell division. Exotoxins are proteins and usually with two parts (A-B) and endotoxins are lipid portion of lipopolysaccharide of outer membrane. The effect of exotoxins on body are specific for a particular cell structure of function in the host, mainly affects cell functions, nerves and gastrointestinal tract. Endotoxins’ effect on body are general and it includes fever, weakness, aches and shock. Exotoxins is heat-unstable and usually can be destroyed at 60-80 degrees. Endotoxins are stable and can withstand autoclaving. The toxicity of exotoxin is high and toxicity of endotoxin is low. Exotoxins do not cause fever while endotoxins cause fever (Tortora, et al., 2016).
There are three types of exotoxins, A-B toxins, membrane-disrupting toxins and superantigens. One examples of membrane-disrupting exotoxins is clostridium perfringens and other species of clostridium which cause gas gangrene and food poisoning. One exotoxin (cytotoxin) causes massive red blood cell destruction which is called hemolysis and exotoxin (enterotoxin) is related to food poisoning and causes diarrhea. All endotoxins produce the same signs and symptoms which include chills, fever, weakness, generalized aches and shock or even death. One example of endotoxins is salmonella typhi which cause typhoid fever (Tortora, et al., 2016).
Reference:
Tortora, G. J., Funke, B. R., & Case, C. L. (2016). Microbiology (12th Edition).
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