Localization of enzymically enhanced heavy metal accumulation by Citrobacter sp. and metal accumulation in vitro by liposomes containing entrapped enzyme

Publisher Website
Google Scholar
Abstract
Summary: Growth of Pseudomonas aeruginosa ATCC 15692 was promoted when the strain was cultured in an iron-depleted succinate medium, supplemented with transferrin at 30%, 60% and 100% and lactoferrin at 60% and 100% iron-saturation. No significant differences between cell growth and pyoverdin production were observed when transferrin iron saturation was increased from 30% to 100%; however, cell growth and pyoverdin production were strongly dependent on lactoferrin iron saturation. Lower lactoferrin iron saturation (< 30%) resulted in more pyoverdin production and reduced cell growth. Incubation of pyoverdin (1.0 μM) with 10.0 μM transferrin (30%, 60% and 100% iron-saturated) or lactoferrin (60% and 100% iron-saturated) led to quenching of pyoverdin fluorescence. Also, 24 h incubation of pyoverdin (20.0 μM) with these two proteins (20.0 μM, 30%, 60% and 100% iron-saturated transferrin and 60% and 100% iron-saturated lactoferrin) at 25 °C resulted in increased absorbency at 460 nm. Both the fluorescence quenching and absorbance increases were iron-saturation-dependent. Taken together, these results support the conclusion that at physiological pH, P. aeruginosa pyoverdin can acquire iron from partially iron-saturated transferrin or lactoferrin.
Funding Information
  • State and Hatch funds appropriated to the University of Georgia, College of Agriculture & Environmental Sciences Experiment Stations