UTILIZATION OF TRANSFERRIN-BOUND IRON BY LISTERIA-MONOCYTOGENES

It has been demonstrated that under iron-restricted conditions, Lister ia monocytogenes can utilize iron-loaded transferrin (Tf) from a range of species as its sole source of iron for growth. Human transferrin c onjugated to horseradish-peroxidase (HRP-Tf) bound directly to whole c ells of L. monocytogenes. This binding was blocked by apotransferrin i ndicating that the receptor can bind transferrin in either the iron-bo und or iron-free form. Transferrin-binding was not host specific becau se both bovine and equine transferrin, inhibited the binding of HRP-co njugated human transferrin. SDS-PAGE and Western blotting of bacterial surface extracts revealed the presence of a transferrin-binding prote in of approximately 126 kDa.