THE EFFECT OF IRON ON THE INVASIVENESS OF ESCHERICHIA-COLI CARRYING THE INV GENE OF YERSINIA-PSEUDOTUBERCULOSIS

The effect of growth in iron-excess or iron-limitation conditions on the invasiveness for HeLa cells of Escherichia coli HB101 carrying plasmid pRI203 which bears the invasion gene of Yersinia pseudotuberculosis was examined. Iron-limitation reduced adhesion and the number of organisms internalised by HeLa cells by about 100-fold. The reduced adhesion of iron-starved bacteria correlated with reduced hydrophobicity and the reduced invasiveness appeared to depend on the plasmid copy number, which was 3.5-fold less than in bacteria grown in iron excess.