The outer-membrane protein (OMP) profile of grown under iron-replete and iron-restricted conditions was studied by polyacrylamide gel electrophoresis and immunoblotting. A serotype 1 isolate induced the synthesis of a new 77000 OMP in iron-restricted media while two other proteins of 100000 and 71000 were synthesized in increased amounts. None of these proteins were peptidoglycan-associated or heat-modifiable, and only the 100000 protein showed some degree of disulphide cross-linking. Kinetic analysis revealed that the iron-repressible proteins appeared in the outer membrane within 15 min of establishment of iron-restricted conditions. Analysis of isolates representing serotypes 1 to 12 showed that iron-repressible OMPs of 77000 and 71000 could be induced in all 12 serotypes but that there was some variability in the expression of the 100000 protein. Immunoblotting of OMPs with convalescent sera from -ifected calves indicated that antibodies directed against all three iron-repressible OMPs were present, suggesting that these proteins were expressed .


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error