The CAMP effect of Actinobacillus pleuropneumoniae is caused by Apx toxins.
Actinobacillus pleuropneumoniae shows synergistic haemolysis when cocultured with Staphylococcus aureus on blood agar plates. This CAMP effect has been attributed to a discrete CAMP factor, but also to the A. pleuropneumoniae-RTX-toxins I, II, and III. We examined the CAMP effect of recombinant Escherichia coli strains that secreted each of these toxins, and of A. pleuropneumoniae mutant strains that were devoid of one or more these toxins. We found that the E. coli strains were CAMP positive, whereas the A. pleuropneumoniae strain devoid of functional toxin genes was CAMP negative. This demonstrated that the CAMP effect of A. pleuropneumoniae is caused by the toxins and that no CAMP factor per se exists.
Jansen
R
R
Department of Molecular Biology, DLO-Institute for Animal Science and Health (ID-DLO), Lelystad, The Netherlands.
Briaire
J
J
Kamp
E M
EM
Gielkens
A L
AL
Smits
M A
MA
D016977:Actinobacillus pleuropneumoniae / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D006460:Hemolysin Proteins; D006461:Hemolysis; D006462:Hemolytic Plaque Technique; D009154:Mutation
C085361:ApxII toxin, bacteria; D001426:Bacterial Proteins; D006460:Hemolysin Proteins; C087744:ApxI toxin, Bacteria