Microorganisms and Disease
Type III secretion systems are used to inject "effector" proteins directly into a host cell. Salmonella uses a type III secretion system to help the pathogen to

activate T cells to proliferate and secrete cytokines
survive within macrophages
secrete LT (heat labile toxin) and ST (heat stable toxin) into the lumen of the intestine
survive the acid pH of the stomach

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Microorganisms and Disease
Cholera toxin is an A-B type toxin in which the B portions bind to a receptor on a host cell and the A portion enters the cell to cause

cleavage of rRNA that results in disruption of ribosome function
ADP ribosylation of a G protein that locks it into an active form that stimulates adenylate cyclase to make cAMP
ADP ribosylation of adenylate cyclase that stops production of cAMP
ADP ribosylation of guanylate cyclase that stimulates production of cGMP

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Microorganisms and Disease
Which of the following is common in the disease caused by Coryne-bacterium diphtheriae and Bacillus anthracis?

The most serious disease symptoms are the direct result of toxin action
Both organisms cause skin and respiratory tract infections
Both organisms are gram-positive spore formers
Diphtheria toxin and edema toxin are ADP ribosylating toxins

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