THE EFFECT OF IRON LIMITATION ON THE GROWTH OF AEROMONAS-SALMONICIDA

The effects of the iron-chelating agents ethylenediamine dihydroxyphen ylacetic acid (EDDA), 2,2'-dipyridyl (Dipy) and 8-hydroxyquinoline (8H Q) on the growth of Aeromonas salmonicida were examined. In these stud ies, EDDA caused a small decrease in growth, whereas Dipy and 8HQ redu ced cell growth by 50 and 90%, respectively. The extracellular product s contained a greater proportion of the major protease (70 kD) when ce lls were grown in the presence of the chelating agents. Analysis of th e outer membrane proteins showed that the chelating agents caused a ma rked increase in the proportion of proteins in the 70-90 kD range. The effects of Dipy were compared for a number of strains of A. salmonici da.