Degree Name

MS (Master of Science)



Date of Award


Committee Chair or Co-Chairs

Ranjan N. Chakraborty

Committee Members

Bert C. Lampson, Lee M. Pike


Many gram-negative bacteria produce and secrete siderophores under iron-deficient conditions. Siderophores are low molecular weight compounds (600-1500 Daltons), which chelate ferric iron with an extremely high affinity, and the complex is actively transported across the outer and inner membranes of gram-negative bacteria. There are two main classes of siderophores: catechol and hydroxamate. Catechol-type siderophores chelate ferric iron via hydroxyl groups, and hydroxamate-type siderophores chelate ferric iron via a carbonyl group with an adjacent nitrogen. Rhizobia fix atmospheric nitrogen symbiotically in leguminous plants using the iron-containing enzyme nitrogenase. To satisfy their iron requirements, many rhizobia are known to produce siderophores. Rhizobium leguminosarum Strain IARI 312 is known to infect pigeon pea plants. R. leguminosarum Strain IARI 312 produces both a catechol-type and a hydroxamate-type siderophore when grown under iron deficient conditions. The catechol-type siderophore has been purified and chemically characterized, and is consistent with that of enterobactin.

Document Type

Thesis - unrestricted


Copyright by the authors.

Included in

Biology Commons