EFFECTS OF HOST IRON TRANSPORT COMPOUNDS ON GROWTH-KINETICS AND OUTER-MEMBRANE PROTEIN EXPRESSION OF BILOPHILA-WADSWORTHIA

Since the environmental iron concentration has emerged as an important attribute in the expression of bacterial virulence, the purpose of th is study was to determine the effects of transferrin, lactoferrin, hem e compounds, and inorganic iron sources (ferric and ferrous sulfate) o n the growth of Bilophila wadsworthia and to study its outer membrane composition when grown under these different simulated in vivo conditi ons. Lactoferrin, transferrin, hemin and hemoglobin supported full gro wth of the bacteria in media lacking other iron sources. Bilophila wad sworthia was also capable of growing in the presence of ferrous and fe rric sulfate. Profiles obtained by SDS-PAGE showed two iron-regulated outer membrane proteins (IROMPs) of 190kDa and 88kDa. The 190kDa was s usceptible to proteinase K cleavage in whole cells, indicating its exp osure at the cell surface. These two major IROMPs were expressed in ir on-restricted media supplemented with iron-bound organic sources and r epressed by the addition of inorganic iron sources. (C) 1998 Academic Press.