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The edema factor is delivered into host cells thanks to the protective antigen. When it is in the cell, the edema factor is activated by calmodulin and its enzymatic activity leads to a dramatic elevation of the cAMP range. Cyclic AMP is a second messenger that plays key roles in the signal transduction pathways and thus regulates diverse cellular responses. It binds to three families of signal transducers: cAMP-dependent protein kinases, cyclic nucleotide gated channels, and the guanine nucleotide exchange factor for Ras GTPase homologs Rap1 and Rap2. | The edema factor is delivered into host cells thanks to the protective antigen. When it is in the cell, the edema factor is activated by calmodulin and its enzymatic activity leads to a dramatic elevation of the cAMP range. Cyclic AMP is a second messenger that plays key roles in the signal transduction pathways and thus regulates diverse cellular responses. It binds to three families of signal transducers: cAMP-dependent protein kinases, cyclic nucleotide gated channels, and the guanine nucleotide exchange factor for Ras GTPase homologs Rap1 and Rap2. | ||
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| + | === Symptoms of anthrax === | ||
| + | The anthrax disease develops when the organism enters in contact with spores of ''Bacillus anthracis''. Syptoms are depending on the contamination mode. The cutaneous contamination results from a contact of spores with an injury. It leads to an ulcer and to the formation of vesicles. In 80 % of the cases the wound heals without complications. However, sometimes an oedema can develop itsel and grow. In that case, anthrax can lead to the death of the patient. | ||
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| + | A gastrointestinal contamination can result from the consumption of contaminated meat. This form of anthrax leads to ulcers, nauseas, diarrhoea and blood poisonning. It can also be lethal if it is not rapidly treated. | ||
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| + | Finally, anthrax spores can cause a pulmonary infection by inhalation. The symptoms developed are similar to those of influenza and they evolve into breathing difficulties and hypotension. Blood poisonning and meningitis can also occur. Because of the severe symptoms, the pulmonary infection remains highly lethal. | ||
Revision as of 16:01, 5 January 2013
Anthrax edema factor
Introduction
The anthrax edema factor is an 89 kDa exotoxin produced by Bacillus anthracis, the bacterium that causes anthrax. It is an adenylate cyclase [ATP pyrophospate-lyase (cyclizing)]. Its enzyme classification number is EC 4.6.1.1. The edema factor increases intracellular cyclic AMP (cAMP) concentration in eukaryotic cells. In fact adenylyl cyclases catalyze the conversion of adenosine triphosphate (ATP) into cAMP and pyrophosphate. The edema factor is produced in an inactive form and calmodulin-activated. Bacillus anthracis also secretes other proteins, in particular the protective antigen (83 kDa) and the lethal factor (90 kDa). Edema factor, protective antigen and lethal factor can also be called factor I, II and III respectively.
The edema factor is delivered into host cells thanks to the protective antigen. When it is in the cell, the edema factor is activated by calmodulin and its enzymatic activity leads to a dramatic elevation of the cAMP range. Cyclic AMP is a second messenger that plays key roles in the signal transduction pathways and thus regulates diverse cellular responses. It binds to three families of signal transducers: cAMP-dependent protein kinases, cyclic nucleotide gated channels, and the guanine nucleotide exchange factor for Ras GTPase homologs Rap1 and Rap2.
Symptoms of anthrax
The anthrax disease develops when the organism enters in contact with spores of Bacillus anthracis. Syptoms are depending on the contamination mode. The cutaneous contamination results from a contact of spores with an injury. It leads to an ulcer and to the formation of vesicles. In 80 % of the cases the wound heals without complications. However, sometimes an oedema can develop itsel and grow. In that case, anthrax can lead to the death of the patient.
A gastrointestinal contamination can result from the consumption of contaminated meat. This form of anthrax leads to ulcers, nauseas, diarrhoea and blood poisonning. It can also be lethal if it is not rapidly treated.
Finally, anthrax spores can cause a pulmonary infection by inhalation. The symptoms developed are similar to those of influenza and they evolve into breathing difficulties and hypotension. Blood poisonning and meningitis can also occur. Because of the severe symptoms, the pulmonary infection remains highly lethal.
